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The surgical reconstruction of severe corneal ulcers is a common and crucial component of the clinical practice of veterinary ophthalmology. Numerous surgical techniques are used in dogs for corneal reconstruction, and these techniques may be categorized by the material used to repair the corneal lesion. The first part of the present review described procedures that utilize autogenous ocular tissues, homologous donor tissues, and heterologous donor tissues. In this second part of the review, the categories of biomaterials and keratoprosthetics will be summarized. Biomaterials that are reported for use in dogs include amniotic membrane, porcine urinary bladder acellular matrix, porcine small intestinal submucosa, acellular porcine corneal stroma, and other miscellaneous soft tissue and cartilage grafts (e.g., preserved equine renal capsule, autologous omentum, autologous buccal mucosa membrane, bovine pericardium, and homologous peritoneum). Descriptions of keratoprosthesis surgery in dogs are currently limited, but the use of artificial corneal transplants hold promise for dogs with severe, vision‐compromising corneal disease that is not amenable to other reconstruction techniques. This review describes the results of experimental studies evaluating these graft materials in dogs, and it will summarize the findings and outcomes of the clinical articles published in each material category. Reporting inconsistencies and areas where additional research is required will be highlighted to help guide future studies in this area. A major aim of this review is to help identify potential subjects that could be evaluated in future investigations and that might lead to refinements in clinical practice. [ABSTRACT FROM AUTHOR]

Background: This study aimed to observe corneal and retinal thicknesses at 5 years after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) for myopia, investigate the effect of epithelial remodeling on refractive status and visual quality, and compare retinal thicknesses among fundus tessellation grades. Methods: Patients who received FS-LASIK or SMILE 5 years before were enrolled in this cross-sectional study. After 1:1 propensity score matching, each surgical group obtained 177 patients (177 eyes). Examinations including visual acuity, refraction, corneal and retinal thicknesses, corneal higher-order aberrations (HOAs), and fundus photography were performed in this visit at 5 years after surgery. The Quality of Vision (QoV) questionnaire was used to assess visual symptoms and overall satisfaction. Corneal and retinal thicknesses between groups were compared, contributing factors were analyzed, and correlations with postoperative refractive status, HOAs, QoV scores and overall satisfaction were evaluated. Results: The discrepancy of epithelial thickness between central and pericentral zones in FS-LASIK group was larger than that in SMILE group, which was negatively correlated with postoperative spherical equivalent (SE), positively correlated with spherical aberration (all P < 0.05), but not correlated with QoV scores and overall satisfaction (all P > 0.05) in both surgical groups. There was no statistical difference in stromal thickness and total corneal thickness (all P > 0.05). Most annuluses of epithelial and stromal thicknesse were linearly related to preoperative SE (all P < 0.05). The macular thickness, ganglion cell complex thickness, and retinal nerve fiber layer thickness exhibited comparable values between two surgical groups and four fundus tessellation grades, with no significant association observed with postoperative SE (all P > 0.05). Conclusion: The tendency that epithelial thickness in central zone was thicker than peripheral zone was more obvious at 5 years after FS-LASIK compared to SMILE. This uneven distribution of epithelial thickness might play a role in myopic regression and the changes in HOAs, especially in patients with high myopia, but it had little effect on patients' subjective visual quality and satisfaction. Retinal thicknesses were not affected by these two surgical methods, and they did not appear to be the clinical indicators for myopic regression or fundus tessellation progression. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of the study was to explore the possible correlations between the anterior segment parameters derived from anterior segment swept-source optical coherence tomography (AS-SS-OCT) with the surgically induced corneal astigmatism (CSIA) calculated from total keratometry (TK) measured by AS-SS-OCT. Methods: Seventy-one eyes of 67 patients with age-related cataract who underwent phacoemulsification combined with intraocular lens implantation with 2.2-mm incision were included. The CSIA values were calculated from anterior keratometry (CSIAKant) and TK (CSIATK) measured by AS-SS-OCT, respectively. Hotelling's T2 test was used to evaluate the difference. The correlation of CSIA with various parameters derived from AS-SS-OCT was tested with the Spearman correlation coefficient. Results: The centroid of CSIAKant and of CSIATK were 0.31 ± 0.55 D @ 54° and 0.41 ± 0.59 D @ 51°, with no significant difference (F = 1.283, p = 0.281, Hotelling's T2). The mean absolute CSIAKant and CSIATK were 0.58 ± 0.24 D and 0.65 ± 0.28 D. Spearman test showed that the magnitude of CSIAKant was negatively correlated with preoperative peripheral corneal thickness (PCT, p = 0.045) and the magnitude of anterior keratometry (p = 0.044). The magnitude of CSIATK was negatively correlated with preoperative central corneal thickness (CCT, p = 0.003) and preoperative PCT (p = 0.015). Conclusions: The increased thickness of the peripheral cornea is correlated with the decrease in the magnitude of the CSIA. The correlation we identified between the corneal thickness and the CSIA indicated that certain preoperative parameters should be considered for the prediction of CSIA for a more precise refractive outcome. [ABSTRACT FROM AUTHOR]

To determine the efficacy of sodium chloride (NaCl) 5% drops in comparison to 6% ointment and study tear Osmolarity as an objective measure correlating with clinical findings in the treatment of corneal edema. This is a prospective, randomized, interventional, open-label, crossover study of 40 eyes of 40 patients with corneal edema due to Bullous keratopathy and Fuchs endothelial dystrophy. Subjects were divided into 2 groups by simple randomization: group A received NaCl 5% drops and group B received NaCl 6% ointment. Both treatments were administered four times daily for seven days. Subsequently, after a 1-week wash-out period, switch over of treatment was done. Central corneal thickness (CCT) and tear osmolarity were primarily efficacy variables. Baseline parameters were comparable. The median reduction in CCT from baseline (706.7 ± 58.41 μm), at 6 hours with NaCl 5% drops was 23 μm (-27, 74) and that with NaCl6% ointment was 37.5 μm (-7, 85). The reduction in CCT was more with 6% ointment (p = 0.013). The difference in reduction in CCT between two treatments at one week was not statistically significant, although there was a substantial reduction in thickness with each treatment individually. The change in tear osmolarity from the baseline at 2 Hours with both NaCl5% drops and 6% ointment was significant, and it remained so till 6 h. Side-effects such as stickiness, stinginess, blurring, and foreign body sensation were more with 6% eye ointment. Topical NaCl 6% eye ointment in QID dosage is more effective than NaCl 5% drops in the medical management of corneal edema. In patients symptomatically intolerant to ointment, NaCl 5% eye drops may be prescribed as an effective option. [ABSTRACT FROM AUTHOR]

One of the main causes of visual impairment in children is visual impairment (myopia, hypermetropia, astigmatism), which are associated with refraction, and affect visual performance and school performance of children, as well as have a negative impact of binocular vision disorders.Purpose: To study the peculiarities of the development of individual eye structures in preschool and school-age children.Materials and methods. 5896 children (11 582 eyes) of preschool and school age (1–14 years old) were examined. Healthy children were examined. All children underwent a comprehensive clinical and instrumental ophthalmological examination, which included: visometry, biomicroscopy, refractometry, ophthalmoscopy, tonometry, pachymetry, ultrasound biometry and ophthalmometry.Results. As a result of the study, the dynamics of eye development in children was studied depending on age, the eye parameters, clearly change and the growth of the eyeball ends by the age of 14. It was found that in children aged from 1 to 14 years vision, refraction, anterior-posterior axis length, lens thickness, anterior chamber depth and vitreous volume significantly increased, and accurate indicators were obtained.Conclusion. The data obtained make it possible to understand the dynamics of the development of the eyeball in preschool children and help in predicting the occurrence of various pathologies and their prevention. The conducted studies have shown some differences in the anatomical and optical environments of the eyes in children of Turkmenistan, whose climatic conditions in evolution led to the development of an adaptive mechanism that determined the corresponding parameters of the organ of vision and its ethnic peculiarity. Based on a large number of studies (5896 children), specific sizes of anatomical and optical eye media in children of Turkmenistan have been established.

AIM: To synthesize the current body of research regarding the diurnal variations in intraocular pressure (IOP) and corneal biomechanical and morphological parameters, highlighting their significance in various eye conditions. METHODS: A comprehensive review of studies on the diurnal variations of IOP and corneal parameters was conducted. Tonometry findings from various studies were assessed, including the Goldmann applanation tonometry (GAT) and non-contact tonometers. Data on the variations in central corneal thickness (CCT), corneal curvature, and corneal biomechanics measured by the Ocular Response Analyzer system across different population groups was extracted and analyzed. RESULTS: In both healthy subjects and those with Fuchs dystrophy, IOP and CCT demonstrate marked diurnal declines. GAT remains the gold standard for tonometry, with the highest reliability. However, its measurements are influenced by CCT. Keratoconus patients and those with pseudoexfoliation showed significant diurnal variations in IOP. The biomechanical parameters, especially corneal hysteresis (CH) and the corneal resistance factor (CRF), largely remain stable throughout the day for most of eye conditions, with some exceptions. Notably, the corneal morphology diurnal variation, particularly curvature, yielded mixed conclusions across studies. CONCLUSION: Circadian rhythms significantly influence various corneal parameters, most notably IOP and CCT. Further studies should emphasize standardized approaches larger sample sizes, and delve deeper into less-explored areas, such as the effects of orthokeratology lenses on diurnal biomechanical shifts.

Background: Keratoconus (KCN) is considered a bilateral corneal ectatic disorder characterized by cone-like steepening of the cornea and irregular stromal thinning, which can lead to decreased visual acuity. This study aimed to assess the prevalence and risk factors for the KCN development in Kosovo. Methods and Results: This retrospective study was conducted in the Department of Ophthalmology at the University Clinical Center of Kosovo. The study included 131 respondents, with a total of 262 eyes. Keratometry basis parameters, such as flat keratometry (K1), and steep keratometry (K2), and maximal corneal curvature (Kmax) were determined. Corneal pachymetry was applied to measure the thickness of the cornea. Staging of KCN was done according to the adapted Amsler-Krumeich staging classification system (AK) for anterior data and corneal thickness (CT). Of 262 examined eyes, 240 (91.6%) were KCN eyes, 2(0.8%) were suspect for KCN, and 20(7.6%) were normal. KCN Stage 1 on the AK classification was predominant (P

Abstract Background This study aimed to observe corneal and retinal thicknesses at 5 years after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) for myopia, investigate the effect of epithelial remodeling on refractive status and visual quality, and compare retinal thicknesses among fundus tessellation grades. Methods Patients who received FS-LASIK or SMILE 5 years before were enrolled in this cross-sectional study. After 1:1 propensity score matching, each surgical group obtained 177 patients (177 eyes). Examinations including visual acuity, refraction, corneal and retinal thicknesses, corneal higher-order aberrations (HOAs), and fundus photography were performed in this visit at 5 years after surgery. The Quality of Vision (QoV) questionnaire was used to assess visual symptoms and overall satisfaction. Corneal and retinal thicknesses between groups were compared, contributing factors were analyzed, and correlations with postoperative refractive status, HOAs, QoV scores and overall satisfaction were evaluated. Results The discrepancy of epithelial thickness between central and pericentral zones in FS-LASIK group was larger than that in SMILE group, which was negatively correlated with postoperative spherical equivalent (SE), positively correlated with spherical aberration (all P 0.05) in both surgical groups. There was no statistical difference in stromal thickness and total corneal thickness (all P > 0.05). Most annuluses of epithelial and stromal thicknesse were linearly related to preoperative SE (all P 0.05). Conclusion The tendency that epithelial thickness in central zone was thicker than peripheral zone was more obvious at 5 years after FS-LASIK compared to SMILE. This uneven distribution of epithelial thickness might play a role in myopic regression and the changes in HOAs, especially in patients with high myopia, but it had little effect on patients’ subjective visual quality and satisfaction. Retinal thicknesses were not affected by these two surgical methods, and they did not appear to be the clinical indicators for myopic regression or fundus tessellation progression.

AIM: To evaluate the reliability of measurements of corneal changes with accommodation in healthy eyes using a Scheimpflug imaging-based system and how these measurements distribute in the normal population.METHODS: Prospective, non-randomized, comparative study including 27 healthy subjects(54 eyes), including emmetropia(13 eyes), myopia(17 eyes), hyperopia(4 eyes)and astigmatism(20 eyes)groups. In all cases, a complete eye examination was performed, including the analysis of corneal changes with different accommodative stimuli(+2.00, 0.00 and -3.00 D)using the Pentacam AXL system. The investigation was structured in 2 phases: repeatability analysis and characterization of accommodation-related corneal changes in healthy populations.RESULTS: In the repeatability analysis, the index of height asymmetry(IHA)showed the greatest variability with the three accommodative stimuli, being the results for the rest of parameters acceptable. The group of emmetropes showed significant differences with accommodative changes in the position of maximum keratometry(Kmax; P

The global surge in refractive surgeries, particularly among myopic individuals, has elicited concerns regarding potential inaccuracies in the measurement of intraocular pressure (IOP) post surgery, primarily associated with central corneal thinning. The incidence of elevated IOP after intraocular refractive surgeries is higher than expected and is multifactorial. Myopic eyes have a higher susceptibility to both primary and secondary glaucoma. Consequently, meticulous preoperative screening for glaucoma is imperative, coupled with systematic postoperative follow-up and evaluation. This comprehensive review analyses the etiology, mechanisms, and therapeutic strategies for managing elevated IOP following refractive surgery. We propose an algorithm to summarize the causative factors of elevated IOP and formulate effective interventions in these instances.

Abstract Introduction The purpose of the study was to explore the possible correlations between the anterior segment parameters derived from anterior segment swept-source optical coherence tomography (AS-SS-OCT) with the surgically induced corneal astigmatism (CSIA) calculated from total keratometry (TK) measured by AS-SS-OCT. Methods Seventy-one eyes of 67 patients with age-related cataract who underwent phacoemulsification combined with intraocular lens implantation with 2.2-mm incision were included. The CSIA values were calculated from anterior keratometry (CSIAKant) and TK (CSIATK) measured by AS-SS-OCT, respectively. Hotelling’s T 2 test was used to evaluate the difference. The correlation of CSIA with various parameters derived from AS-SS-OCT was tested with the Spearman correlation coefficient. Results The centroid of CSIAKant and of CSIATK were 0.31 ± 0.55 D @ 54° and 0.41 ± 0.59 D @ 51°, with no significant difference (F = 1.283, p = 0.281, Hotelling’s T 2). The mean absolute CSIAKant and CSIATK were 0.58 ± 0.24 D and 0.65 ± 0.28 D. Spearman test showed that the magnitude of CSIAKant was negatively correlated with preoperative peripheral corneal thickness (PCT, p = 0.045) and the magnitude of anterior keratometry (p = 0.044). The magnitude of CSIATK was negatively correlated with preoperative central corneal thickness (CCT, p = 0.003) and preoperative PCT (p = 0.015). Conclusions The increased thickness of the peripheral cornea is correlated with the decrease in the magnitude of the CSIA. The correlation we identified between the corneal thickness and the CSIA indicated that certain preoperative parameters should be considered for the prediction of CSIA for a more precise refractive outcome.

Abstract Background This study assessed the agreement of ocular parameters of patients with myopia measured using Colombo intraocular lens (IOL) 2 and IOLMaster 700. Methods Eighty patients (male, 22; average age, 29.14 ± 7.36 years) with myopia (159 eyes) were included in this study in May 2023. The participants’ axial length (AXL), central corneal thickness (CCT), lens thickness (LT), white-to-white distance (WTW), front flat (K1), steep (K2), mean (Km) corneal keratometry, astigmatism (Astig), J0 vector, and J45 vector were measured using the IOLMaster 700 and Colombo IOL 2. The measurements from both devices were compared using the generalized estimating equation, correlation analysis, and Bland-Altman plots. Results With the Colombo IOL 2, lower values for K2 and J0 (odds ratio [OR] = 0.587, p = 0.033; OR = 0.779, p

Background: The prevalence of myopia in the 5–15-year age group in India has been 7.5% over the past four decades. While ocular growth and physical growth occur simultaneously during early life, the existence of a common regulatory system for both is still debated. Aims and Objectives: This study aims to analyze the ocular biometry and anthropometric values of young myopes and emmetropes aged 18–25 years. Materials and Methods: This case–control study involved a sample size of 86 participants. Corneal curvature was measured using keratometry, while A-scan ultrasonography was utilized to measure axial length, lens thickness, anterior chamber depth, and vitreous chamber depth. Results: The results indicated that there were no significant differences in ocular biometry and anthropometric values between the case and control groups, except for corneal thickness and axial length. The mean corneal thickness was found to be 549.64 μm in the case group and 566.05 μm in the control group, while the mean axial length was 24.70 mm in the case group and 23.41 mm in the control group. An increase in height was correlated with longer axial length in myopes. Conclusion: There was no difference in anthropometry and ocular biometry in emmetropes and myopes in the age group of 18–25 years of age. Myopes tend to have thinner corneas, which should be taken into consideration before performing refractive surgeries. The presence of thin corneas in individuals with myopia can result in inaccurately low measurements of intraocular pressure, potentially hampering the early detection of glaucoma within this high-risk demographic.

Background: This study assessed the agreement of ocular parameters of patients with myopia measured using Colombo intraocular lens (IOL) 2 and IOLMaster 700. Methods: Eighty patients (male, 22; average age, 29.14 ± 7.36 years) with myopia (159 eyes) were included in this study in May 2023. The participants' axial length (AXL), central corneal thickness (CCT), lens thickness (LT), white-to-white distance (WTW), front flat (K1), steep (K2), mean (Km) corneal keratometry, astigmatism (Astig), J0 vector, and J45 vector were measured using the IOLMaster 700 and Colombo IOL 2. The measurements from both devices were compared using the generalized estimating equation, correlation analysis, and Bland-Altman plots. Results: With the Colombo IOL 2, lower values for K2 and J0 (odds ratio [OR] = 0.587, p = 0.033; OR = 0.779, p < 0.0001, respectively), and larger values for WTW, Astig, and J45 (OR = 1.277, OR = 1.482, OR = 1.1, all p < 0.0001) were obtained. All ocular measurements by both instruments showed positive correlations, with AXL demonstrating the strongest correlation (r = 0.9996, p < 0.0001). The intraclass correlation coefficients for AXL and CCT measured by both instruments was 0.999 and 0.988 (both p < 0.0001), and Bland-Altman plot showed 95% limits of agreement (LoA) of -0.078 to 0.11 mm and − 9.989 to 13.486 μm, respectively. The maximum absolute 95% LoA for LT, WTW, K1, K2, and J0 were relatively high, achieving 0.829 mm, 0.717 mm, 0.983 D, 0.948 D, and 0.632 D, respectively. Conclusions: In young patients with myopia, CCT and AXL measurements obtained with the Colombo IOL 2 and IOLMaster 700 were comparable. However, WTW, LT, corneal refractive power, and astigmatism values could not be used interchangeably in clinical practice. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Pterygium is a common ocular surface disorder characterized by a fibrovascular growth extending onto the cornea, often leading to visual impairment through induced astigmatism and corneal distortion. Surgical excision is the primary treatment, with Amniotic Membrane Grafts (AMG) and Conjunctival Autografts (CAG) being the prevalent techniques. This study aims to compare the autorefractive changes post-pterygium excision using AMG versus CAG. MATERIALS AND METHODS: This prospective comparative study included 25 eyes from 25 patients with nasal pterygium, who underwent excision surgery at the Sree Mookambika Institute of Medical Sciences between July 2022 and December 2023. Patients were divided into two groups: 13 underwent AMG and 12 underwent CAG. Preoperative and postoperative assessments included Best Corrected Visual Acuity (BCVA), autorefractometry, pachymetry, and anterior segment examination. Statistical analysis was performed using the Student t-test, with significance set at p < 0.05. RESULTS: Both AMG and CAG groups showed significant reductions in astigmatism postoperatively, though differences between the two techniques were not statistically significant (AMG: p = 0.34; CAG: p = 0.28). Vision improved significantly from a mean BCVA of 0.47 ± 0.36 to 0.68 ± 0.25 (p = 0.01), and central corneal thickness increased from 516.16 ± 38.03 µm to 533.44 ± 34.32 µm (p = 0.02). The recurrence rate was lower in the CAG group (5.3%) compared to the AMG group (10.5%). CONCLUSION: Both AMG and CAG techniques effectively reduce postoperative astigmatism and improve visual outcomes following pterygium excision. Despite similar refractive outcomes, CAG may offer advantages in terms of recurrence rates. Further research with larger sample sizes and longer follow-up periods is warranted to delineate the long-term benefits of each technique. [ABSTRACT FROM AUTHOR]

Background: The prevalence of myopia in the 5–15-year age group in India has been 7.5% over the past four decades. While ocular growth and physical growth occur simultaneously during early life, the existence of a common regulatory system for both is still debated. Aims and Objectives: This study aims to analyze the ocular biometry and anthropometric values of young myopes and emmetropes aged 18–25 years. Materials and Methods: This case–control study involved a sample size of 86 participants. Corneal curvature was measured using keratometry, while A-scan ultrasonography was utilized to measure axial length, lens thickness, anterior chamber depth, and vitreous chamber depth. Results: The results indicated that there were no significant differences in ocular biometry and anthropometric values between the case and control groups, except for corneal thickness and axial length. The mean corneal thickness was found to be 549.64 μm in the case group and 566.05 μm in the control group, while the mean axial length was 24.70 mm in the case group and 23.41 mm in the control group. An increase in height was correlated with longer axial length in myopes. Conclusion: There was no difference in anthropometry and ocular biometry in emmetropes and myopes in the age group of 18–25 years of age. Myopes tend to have thinner corneas, which should be taken into consideration before performing refractive surgeries. The presence of thin corneas in individuals with myopia can result in inaccurately low measurements of intraocular pressure, potentially hampering the early detection of glaucoma within this high-risk demographic. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of pregnancy on the anterior chamber, corneal parameter, and intraocular pressure measurements; and compare the results between trimesters, postpartum and non-pregnant healthy age-matched women. Methods: This prospective study included 41 pregnant women and 53 non-pregnant women. Four measurements were taken from the pregnant women, in each trimester and postpartum third month, and once from the control group. Of the individuals included in the study, anterior chamber depth (ACD), anterior chamber volume (ACV), K1 (flat keratometry), K2 (steep keratometry), Kmean (mean value of K1 and K2), anterior chamber angle (ACA), central corneal thickness (CCT), thinnest corneal thickness (TCT), astigmatism value (AST), corneal volume (CV), biometry, axial length (AL), spherical equivalent (SFEQ), intraocular lens power (ILP), VA (visual acuity) datas were recorded. Results: We observed a statistically significant decrease in K2, CCT, ACD, AL and CV in the postpartum period (p = 0.025, p < 0.001, p = 0.029, p = 0.005, p = 0.004 respectively) and a statistically significant increase in ACV, CCT, and TCT as the gestational week progressed in the pregnant group (p = 0.007, p < 0.001, p = 0.025, respectively). A statistically significant decrease in IOP towards to the third trimester, and an increase in the postpartum period was observed (p < 0.001). We did not observe statistically significant changes in K1, Kmean, AST, ACA, VA, ILP, and SFEQ values. Conclusion: It is important to investigate the physiological changes that may occur during pregnancy, distinguish them from pathological changes, and avoid unnecessary treatment. We consider that it's also important to guide the timing of anterior segment surgeries such as cataract and refractive surgery and to prescribe glasses/contact lenses. [ABSTRACT FROM AUTHOR]

Abstract Background The precision of anterior segment biometric measurements in eyes has become increasingly important in refractive surgery. The purpose of this study is to assess the repeatability of the automatic measurements provided by a new spectral-domain optical coherence tomograph (SD-OCT)/Placido topographer (MS-39, CSO) and its agreement with a swept-source OCT (SS-OCT) biometer (CASIA SS-1000, Tomey) in patients with myopia. Methods The right eye of 235 subjects was scanned 3 times with both devices. The evaluated parameters included central corneal radius of the steep meridian, central corneal radius of the flat meridian, mean central corneal radius, thinnest corneal thickness, central corneal thickness, anterior chamber depth, corneal volume and diameter. The intraobserver repeatability of the MS-39 measurements was calculated using intraclass correlation coefficient (ICC), within subject standard deviation, coefficient of repeatability, coefficient of variation and repeated-measures analysis of variance of the 3 repeated measurements. The agreement between the two devices was evaluated by 95% limits of agreement (LoA). Results The majority of the parameters acquired from MS-39 showed high repeatability. The repeatability of corneal diameter was slightly lower than the other measurements, although the ICC remained high. Agreement with the CASIA SS-1000 was good, indicated by the Bland-Altman plots with narrow 95% LoA values for all parameters assessed. Conclusions The high repeatability of automatic measurements by the new device supports its clinical application in eyes with myopia, and the good agreement between the two devices indicates they could be used interchangeably for the parameters evaluated.

AIM: To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty (SLAK) with corneal crosslinking (CXL) on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis (FS-LASIK). METHODS: A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo. The lenticules were collected from patients undertaking small incision lenticule extraction (SMILE) for the correction of myopia. Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength. RESULTS: All surgeries were conducted successfully with no significant complications. Their best corrected visual acuity (BCVA) ranged from 0.05 to 0.8-2 before surgery. The pre-operational total corneal thickness ranged from 345-404 μm and maximum keratometry (Kmax) ranged from 50.8 to 86.3. After the combination surgery, both the corneal keratometry (range 55.9 to 92.8) and total corneal thickness (range 413-482 μm) significantly increased. Four out of 5 patients had improvement of corneal biomechanical parameters (reflected by stiffness parameter A1 in Corvis ST). However, 3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze. Despite the onset of corneal edema right after SLAK, the corneal topography and thickness generally stabilized after 3mo. CONCLUSION: SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia. Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.

AIM:To investigate the effect of wearing corneoscleral contact lens on visual acuity, and corneal parameters in keratoconus patients.METHODS:In this prospective study, 43 cases(83 eyes)with keratoconus were included and examined. A corneoscleral contact lens was fitted, and thorough exams were carried out at baseline, 3 and 6 mo after wearing lenses, including slit lamp examination, objective and subjective refraction, uncorrected visual acuity(UCVA), and best-corrected visual acuity(BCVA), keratometry(Kmax, K1 and K2), central corneal thickness and endothelial cells count.RESULTS: Mean BCVA(LogMAR)improved from 0.34±0.23 with the spectacles to 0.03±0.05 with the corneoscleral contact lenses in 6 mo(P

Abstract Background Several studies have previously reported the normal values of corneal volume (CV) in various populations, whereas little is known about the CV distribution in healthy young Chinese adults. Our study aimed to investigate the distribution of CV and its relationships with other ocular biometric parameters among healthy young Chinese adults. Methods A total of 1645 eyes from 1645 students at Dali University in Yunnan Province, China, were analyzed. Pentacam was used to measure CV. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated by Corvis-ST. Other biometrical parameters, including axial length (AL), keratometry, and white-to-white (WTW) distance, were measured using IOL Master. Results The mean age of the study population was 19.01 ± 0.92 years, and 68.81% of them were women. The CV was normally distributed in the whole sample, with a mean value of 61.23 ± 3.22 mm3. CV and CCT were significantly smaller in the Yi ethnic group than in the Han ethnic group (p

Background: The precision of anterior segment biometric measurements in eyes has become increasingly important in refractive surgery. The purpose of this study is to assess the repeatability of the automatic measurements provided by a new spectral-domain optical coherence tomograph (SD-OCT)/Placido topographer (MS-39, CSO) and its agreement with a swept-source OCT (SS-OCT) biometer (CASIA SS-1000, Tomey) in patients with myopia. Methods: The right eye of 235 subjects was scanned 3 times with both devices. The evaluated parameters included central corneal radius of the steep meridian, central corneal radius of the flat meridian, mean central corneal radius, thinnest corneal thickness, central corneal thickness, anterior chamber depth, corneal volume and diameter. The intraobserver repeatability of the MS-39 measurements was calculated using intraclass correlation coefficient (ICC), within subject standard deviation, coefficient of repeatability, coefficient of variation and repeated-measures analysis of variance of the 3 repeated measurements. The agreement between the two devices was evaluated by 95% limits of agreement (LoA). Results: The majority of the parameters acquired from MS-39 showed high repeatability. The repeatability of corneal diameter was slightly lower than the other measurements, although the ICC remained high. Agreement with the CASIA SS-1000 was good, indicated by the Bland-Altman plots with narrow 95% LoA values for all parameters assessed. Conclusions: The high repeatability of automatic measurements by the new device supports its clinical application in eyes with myopia, and the good agreement between the two devices indicates they could be used interchangeably for the parameters evaluated. [ABSTRACT FROM AUTHOR]

Purpose: To determine the absorbance coefficient of the thin porcine cornea to ultraviolet-A radiation (365 nm) submitted for crosslinking. Methods: This in vitro, benchtop experiment using cadaver tissue study analyzed 12 porcine corneal lamellas, which were obtained using a microkeratome after mechanical de-epithelization and separated into three thickness groups: 180, 300, and 360 µm. The corneal thickness values were measured by anterior-segment optical coherence tomography. All lamellas had ultraviolet-A (365 nm) absorbance measured with a 96-well plate spectrophotometer using an ultraviolet transparent microplate before riboflavin instillation and pre- and post-crosslinking according to the Dresden protocol. Results: The ultraviolet absorbance profiles of the 180, 300, and 360 µm groups were obtained as α-coefficients of 12.85, 76.55, and 120.27, respectively. A theoretical formula was calculated though a statistical analysis that demonstrated the correlation between stromal lamellar thickness and ultraviolet absorbance. Conclusions: Corneal thickness and ultraviolet-A spectral absorbance of corneal lamellas showed linear correlation. These findings can potentially contribute to the optimization of ultraviolet-A application during crosslinking, making the treatment of corneas with thickness <400 µm safe and personalized energy delivery for each corneal thickness. [ABSTRACT FROM AUTHOR]

Simple Summary: The problem addressed in this study is the development of pigmentary keratitis (PK) in Pug-breed dogs, a condition characterized by corneal pigmentation and associated with ocular manifestations and vision loss. The aim of the study was to assess the occurrence of PK in Pug dogs, identify predisposing factors, and evaluate the tear film quantity and quality in affected dogs. The study found that the prevalence of PK was high in dogs, with 94.5% of eyes showing PK. The severity of corneal pigmentation varied, with very mild (20.3%), mild (16.4%), moderate (38.2%), and severe (25.1%) categories observed. Age and previous ocular diseases were identified as potential risk factors for the development of severe PK. The main conclusion of the study is that PK in Pug-breed dogs in the Canary Islands has a high prevalence and may have a genetic basis. Our most relevant contribution is the evaluation based on the Tear Break-Up Time (TBUT) test and the Tear Ferning Test (TFT). This information can be valuable to society by helping veterinarians diagnose and treat PK in Pugs and potentially prevent the disease through genetic screening and breeding practices. This study investigated the prevalence of pigmentary keratitis (PK) in Pug-breed dogs and described the ocular surface characteristics associated with this disease. A total of 219 eyes from 110 dogs were examined, with 94.5% of them affected by PK. Age, previous ocular diseases, corneal vascularization, and corneal sensitivity were significantly associated with the presence of PF and the severity of corneal pigmentation. The study also found that low tear production and blinks incomplete with tear signs, as well as reduced corneal sensitivity, were linked to more severe forms of corneal pigmentation. The Tear Ferning Test (TFT) was identified as a valuable tool for evaluating tear quality in dogs, with worse test results indicating a higher risk of severe PK. A lower mean Tear Break-Up Time (TBUT) test was observed in dogs with PK. Additionally, the study observed a statistically significant difference in corneal thickness between the nasal and temporal zones, with the nasal zone being thicker. It was also suggested that sex and fertility status may influence the incidence of PK and the severity of corneal pigmentation. Overall, these findings provide insight into the underlying causes of PK in Pugs and can inform future treatment strategies for this breed. [ABSTRACT FROM AUTHOR]

Background: Several studies have previously reported the normal values of corneal volume (CV) in various populations, whereas little is known about the CV distribution in healthy young Chinese adults. Our study aimed to investigate the distribution of CV and its relationships with other ocular biometric parameters among healthy young Chinese adults. Methods: A total of 1645 eyes from 1645 students at Dali University in Yunnan Province, China, were analyzed. Pentacam was used to measure CV. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated by Corvis-ST. Other biometrical parameters, including axial length (AL), keratometry, and white-to-white (WTW) distance, were measured using IOL Master. Results: The mean age of the study population was 19.01 ± 0.92 years, and 68.81% of them were women. The CV was normally distributed in the whole sample, with a mean value of 61.23 ± 3.22 mm3. CV and CCT were significantly smaller in the Yi ethnic group than in the Han ethnic group (p < 0.01). CCT (coefficient: 0.085; p < 0.001) and keratometry (coefficient: 0.422; p < 0.001) were positively correlated with CV, while AL (coefficient: -0.204; p < 0.001), WTW distance (coefficient: -0.236; p < 0.001) and bIOP (coefficient: -0.06; p < 0.001) were inversely associated with CV. Conclusions: Our study provides an age-specific distribution of CV among healthy young Chinese adults. CCT, keratometry, AL, WTW distance and bIOP were important factors associated with CV. [ABSTRACT FROM AUTHOR]

Keratoconus is a corneal disease which results in progressive thinning and protrusion of the cornea leading to irregular astigmatism. The purpose of this study was to evaluate longitudinal changes in corneal volume (CV) occurring over time in keratoconus eyes. Consecutive patients affected by keratoconus were evaluated by means of anterior segment-optical coherence tomography (AS-OCT) at two different time points: baseline (T0) and after 1 year (T1). Anterior and posterior refractive value; corneal thickness at the thinnest point (TP) and corneal volume (CV) calculated within discs of 3, 5 and 8 mm of diameter; anterior chamber depth (ACD); and anterior chamber volume (ACV) were obtained. Enrolled patients were divided into 3 groups (groups 1, 2, 3) according to the increasing disease severity and into 2 groups (groups A, B) according to the progression or stability of the disease. Overall, 116 eyes of 116 patients (76 males and 40 females, mean age 34.76 ± 13.99 years) were included. For the entire group of keratoconus patients, in comparison with T0, mean TP decreased at T1 from 458.7 ± 52.2 µm to 454.6 ± 51.6 µm (p = 0.0004); in parallel, mean value of CV calculated at 5 mm and 8 mm decreased significantly (from 10.78 ± 0.8 at T0 to 10.75 ± 0.79 at T1 (p = 0.02), and from 32.03 ± 2.01 mm3 at T0 to 31.95 ± 1.98 at T1 (p = 0.02), respectively). Conversely, there were no statistically significant differences in CV at 3 mm from T0 to T1 (p = 0.08), as well as for ACD and ACV. Regarding the course of the disease, patients belonging to group A showed statistically significant differences from T0 to T1 for TP, and for CV at 3 mm, 5 mm and 8 mm (p < 0.0001, p < 0.0001, p < 0.001 and p = 0.0058 respectively). There were no statistically significant differences for ACD (p = 0.6916) and ACV calculated at 3, 5 and 8 mm (p = 0.7709, p = 0.3765, p = 0.2475, respectively) in group A. At the same time, no statistically significant differences for ACD (p = 0.2897) and ACV calculated at 3, 5 and 8 mm (p = 0.9849, p = 0.6420, p = 0.8338, respectively) were found in group B. There were statistically significant positive correlations between changes of TP and CV at 3 mm (r = 0.6324, p < 0.0001), 5 mm (r = 0.7622, p < 0.0001) and 8 mm (r = 0.5987 p < 0.0001). In conclusion, given the strong correlation with TP, CV might be considered an additional AS-OCT parameter to be used in association with conventional parameters when detecting longitudinal changes in keratoconic eyes. [ABSTRACT FROM AUTHOR]

Purpose: To assess the corneal parameters in rheumatoid arthritis (RA) patients. Methods: We enrolled 64 patients with RA (32 receiving biologic and 32 receiving conventional drugs) and 32 healthy subjects. Keratometric values (anterior flat [K1], steep [K2], and mean keratometry [Km]), corneal thickness from the pupil center (CCT), apex (ACT), and the thinnest point (TCT), and corneal volume (CV) were measured and compared between the groups. Results: K1, K2, and Km values were significantly higher in the RA group (P = 0.013, P = 0.048, P = 0.027, respectively). The means of CCT, ACT, TCT, and CV were significantly lower in RA patients (P < 0.001, P < 0.001, P < 0.001, P = 0.011, respectively). When we divided RA patients into two groups according to the treatment and compared them to controls, the differences in K1, CCT, ACT, TCT and CV were significant (P = 0.030, P = 0.005, P = 0.001, P = 0.001, P = 0.034, respectively). K1 and CV values of RA-biologic group were similar to the control group (P = 0.205 and P = 0.127, respectively). Conclusion: Biologic agents contribute to the improvement of K1 and CV values in patients with RA. [ABSTRACT FROM AUTHOR]

PurposeTo define the normal range of central corneal thickness (CCT) and corneal endothelial cell density (ECD) in rhesus macaques (Macaca mulatta) and the effects of age, body weight, sex, and intraocular pressure (IOP) on these parameters.MethodsOphthalmic examinations were performed on 144 rhesus macaques without anterior segment pathology. The CCT was measured via ultrasound pachymetry (USP) and specular microscopy, and the ECD was semiautomatically and manually counted using specular microscopy. Rebound tonometry was used to measure IOP. Linear regression and mixed-effects linear regression models were used to evaluate the effects of age, body weight, sex, and IOP on CCT and ECD.ResultsWe included 98 females and 46 males with an age range of 0.2 to 29.4 years. The mean CCT by USP and specular microscopy were 483 ± 39 and 463 ± 33 µm, respectively, and were statistically different (P < 0.001). The ECDs were 2717 ± 423 and 2747 ± 438 cells/mm2 by semiautomated and manual analysis, respectively. Corneal endothelial degeneration was identified in one aged rhesus macaque.ConclusionsThe mean USP and specular microscopy CCT values differed significantly, whereas the semiautomatic and manual ECD did not. The CCT was associated with the IOP and sex, whereas the ECD was associated with body weight and age (P < 0.05). As in humans, corneal disease in rhesus macaques is uncommon.Translational relevanceEstablishing reference values is fundamental to use rhesus macaques as a model for corneal disease or to identify toxicity in studies of ocular drugs or devices.

Background: Various demographic and ocular factors influence central corneal thickness (CCT). Studies on the relationships between these parameters have shown conflicting results. We aim to investigate the correlation of CCT with different types of refractive error, axial length (AL), and corneal curvature. Materials and Methods: An observational study was undertaken in the Department of Ophthalmology, recruiting patients from 18 to 40 years of age with myopia (−0.5 D to −6 D) or hypermetropia (≤ +3 D) or emmetropia (−0.25 D to +0.25 D). All participants underwent comprehensive ophthalmic examination, including refraction, slit lamp examination and fundoscopy, followed by CCT, corneal curvature, and AL measurement. Result: A total of 1224 eyes of 612 patients (260 males and 352 females) were enrolled in the study. Out of them, 31.5% (n = 386) had emmetropia, 28.6% (n = 350) had hypermetropia, and 39.9% (n = 488) had myopia. The mean (±standard deviation [SD]) keratometry (K), CCT and AL were found to be 44.08 (±1.55) D, 528.46 (±29.78) μm, and 22.75 (±1.21) mm, respectively. With increasing age, CCT was found to be decreased (P < 0.001). Compared to myopia, a significantly higher CCT was noted in hypermetropia (P < 0.001). There was a negative correlation between CCT and corneal curvature among the entire study population, irrespective of their refractive status (P < 0.001). This correlation was more significant among emmetropes and hypermetropes as compared to myopes. However, we found no correlation between CCT and AL in any groups. Conclusion: CCT is found to be thicker in hypermetropia and thinner in myopia as compared to emmetropia. With increasing age, the cornea tends to become steeper and thinner.

Purpose: To assess the corneal parameters in rheumatoid arthritis (RA) patients. Methods: We enrolled 64 patients with RA (32 receiving biologic and 32 receiving conventional drugs) and 32 healthy subjects. Keratometric values (anterior flat [K1], steep [K2], and mean keratometry [Km]), corneal thickness from the pupil center (CCT), apex (ACT), and the thinnest point (TCT), and corneal volume (CV) were measured and compared between the groups. Results: K1, K2, and Km values were significantly higher in the RA group (P = 0.013, P = 0.048, P = 0.027, respectively). The means of CCT, ACT, TCT, and CV were significantly lower in RA patients (P < 0.001, P < 0.001, P < 0.001, P = 0.011, respectively). When we divided RA patients into two groups according to the treatment and compared them to controls, the differences in K1, CCT, ACT, TCT and CV were significant (P = 0.030, P = 0.005, P = 0.001, P = 0.001, P = 0.034, respectively). K1 and CV values of RA-biologic group were similar to the control group (P = 0.205 and P = 0.127, respectively). Conclusion: Biologic agents contribute to the improvement of K1 and CV values in patients with RA.

Abstract Purpose: This study aimed to compare the thickness profile and the endothelial cell density (ECD) of donated corneas maintained in Optisol-GS with those preserved in Sinasol over seven days. Methods: Twenty paired donor corneas were received from the Central Eye Bank of Iran. After recording the osmolarity of each medium, one of each of the cornea pairs was preserved in either Optisol-GS or Sinasol media. Then, slit-lamp biomicroscopy and specular microscopic examinations were performed at the baseline and on day seven. Visante optical coherence tomography (V-OCT) was also performed at 1 hour (h), 24h, 72h, and one week post-preservation. The specular microscopic and V-OCT values were then compared between the two groups. Results: The mean osmolarity of the Sinasol group was significantly less than the Optisol-GS group (296 vs. 366 mOsm/L, P = 0.0008). The mean central corneal thickness at the measurement points was comparable between the two groups. However, the increase of thickness one week post-preservation in the Sinasol group was remarkably lower than those in the Optisol-GS group ( P = 0.027). The mean ECD was comparable between the groups at the baseline and on day seven. However, the mean change of ECD from baseline to day seven was considerably higher in the Optisol-GS group than in the Sinasol group ( P = 0.019). Conclusion: Corneal storage in Sinasol over seven days provides better and superior maintenance and preservation of corneal tissue deturgescence and a lower rate of ECD loss over Optisol-GS.

ObjectiveTo determine corneal thickness (CT) and axial anterior chamber depth (ACD) using ultrasound biomicroscopy (UBM) in normal adult horses. To compare corneal thickness measurements between UBM and ultrasonic pachymetry.Animals studiedSixty eyes of 30 healthy adult horses aged 8-24 years.ProceduresUltrasonic pachymetry (velocity of 1640 m/s) was utilized to obtain measurements of the central, superior, temporal, inferior, and nasal cornea. Triplicate images of the same corneal locations were acquired using UBM (50 MHz). Images of the axial anterior chamber were used to measure ACD. Intraocular pressure (IOP) was estimated using rebound tonometry, and axial globe length was measured using ultrasonographic biometry.ResultsCT (mean ± SD µm) measured by UBM was 854 ± 61 (central), 994 ± 58 (superior), 930 ± 57 (temporal), 979 ± 55 (inferior), and 898 ± 48 (nasal). CT measured by UBM was greater than that measured by ultrasonic pachymetry at all locations and was statistically significant at all locations except inferior (p = 0.0006-0.048). No sex nor age effect was detected for CT at any location. The repeatability of ultrasonic pachymetry was superior to that of UBM. Mean ± SD ACD was 5.74 ± 0.41 mm. A weak positive correlation was identified between central CT and IOP and between central CT and axial globe length.ConclusionsNormal data for CT and ACD of the adult horse obtained using UBM are provided. CT determined by UBM was greater relative to pachymetry at all corneal locations.

Accurate thickness measurement of corneal layers using anterior segment OCT can be used to improve visual outcomes. Understanding its applications is essential for optometric practices to enhance eye care procedures. To evaluate the thicknesses of different corneal layers for identifying keratoconus (KCN) and subclinical keratoconus (SKCN) using spectral-domain optical coherence tomography (SD-OCT). This prospective study analyzed 60 eyes with KCN, 48 eyes with SKCN, and 53 normal eyes. The central corneal thickness (CCT) and thicknesses of the epithelium, Bowman, stroma, and Descemet-endothelium layers were measured using SD-OCT. One way analysis of variance and the area under the curve (AUC) were used to evaluate the parameters. The Delong method was used to compare AUCs. In KCN, CCT and thicknesses of epithelium, Bowman, stroma, and Descemet-endothelium layers were 495.5 ± 41.7, 52.6 ± 6.4,11.5 ± 1.4, 415.5 ± 38.9, and 12.3 ± 1.7 µm, respectively. These thickness values were respectively 524.5 ± 33.3, 56.8 ± 6.8, 11.5 ± 1.6, 439.8 ± 30.6, and 12.4 ± 1.7 µm in SKCN and 563.8 ± 37.9, 57.7 ± 6.9, 12.2 ± 1.6, 469.5 ± 33.7, and 12.8 ± 2.1µm in normal group. Total cornea and stroma in KCN and SKCN, and epithelium in KCN were significantly thinner compared to the normal group (P < 0.001). The highest AUC values were observed for CCT in KCN (AUC 0.90) and SKCN (AUC 0.782). The diagnostic accuracy was significantly higher for stromal thickness in KCN (sensitivity 81.7%, specificity 73.6%, AUC 0.871) and SKCN (sensitivity 80.0%, specificity 56.6%, AUC 0.751) than other individual corneal layers (Delong, P < 0.001). CCT can accurately distinguish keratoconus from normal eyes. However, central corneal stromal thinning was the most sensitive diagnostic index for early detection of SKCN. Developing standardized stromal maps may be helpful for detecting SKCN. [ABSTRACT FROM AUTHOR]

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The aim of this study is to analyze the anterior and posterior corneal surface shape and the corneal thickness difference outcomes between before and after scleral lens (ScCL) wear in post-LASIK ectasia subjects for one year. Twenty eyes with post-LASIK ectasia wearing scleral lenses were evaluated in a visit before contact lens and after 1, 6, and 12 months. The study variables analyzed included the apex, nasal, temporal, inferior, and superior corneal thickness; the anterior and posterior surface corneal at corneal diameters of 8, 6, 4, and 2 mm, and high-contrast visual acuity. A statistically significant increment of corneal thickness (p < 0.05) was observed in the inferior area after 6 months and in the superior area in the 12-month follow-up after wearing ScCLs. The anterior corneal curvature presented a flattening and a statistically significant steepening (p < 0.05) in the central and peripheral radii, respectively, after one year. The posterior corneal curvature showed a significant (p < 0.05) steepening, which mainly affected the central region after one year. Despite these changes, high-contrast visual acuity with ScCL correction remained at the same values. The prolonged use of scleral lenses in post-LASIK subjects showed significant changes in the corneal curvature and thickness. These outcomes recommend more detailed and periodic topographic and vision quality checks to monitor the wear in ScCL patients. [ABSTRACT FROM AUTHOR]

Chia-Wen Hsiao,1 Hang Cheng,1 Rana Ghafouri,2 Nicole C Ferko,2 Brandon D Ayres3 1Alcon, Fort Worth, TX, USA; 2Eversana, Burlington, ON, Canada; 3Thomas Jefferson University Hospital, Philadelphia, PA, USACorrespondence: Nicole C Ferko, Eversana Life Science Services, 3228 S Service Road, Burlington, ON, Canada, Tel +1 (905) 978-3111, Email nicole.ferko@eversana.comBackground: Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT).Methods: MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT®, DuoVisc® or DisCoVisc®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs.Results: A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: − 4.10%; 95% CI: − 5.81 to − 2.40; p < 0.0001; 9 studies) and HPMC (MD: − 6.47%; 95% CI: − 10.41 to − 2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: − 3.22%; 95% CI: − 6.24% to − 0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: − 0.43% to 0.95%; p = 0.4; 2 studies).Conclusion: CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.Keywords: cataract, ophthalmic viscosurgical device, endothelial cell density, corneal thickness, endothelial protection

Ossama Mahmoud,1,2 Chris Andrews,1 Timothy Soeken,1 Sudha Nallasamy,3,4 Nambi Nallasamy1,5 1Kellogg Eye Center Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA; 2School of Medicine, Wayne State University, Detroit, MI, USA; 3The Vision Center, Children’s Hospital Los Angeles, Los Angeles, CA, USA; 4USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, LA, California, USA; 5Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USACorrespondence: Nambi Nallasamy, Kellogg Eye Center, University of Michigan, 1000 Wall St, Ann Arbor, MI, 48105, USA, Tel +1 734 763-5506, Fax +1 734 936-2340, Email nnallasa@med.umich.eduBackground: Orthokeratology has been shown to suppress progressive myopia in some children. We examine the changes in optical biometry parameters in orthokeratology (Ortho-K) patients, in a retrospective longitudinal study at a tertiary eye care center in Ann Arbor, MI, USA.Methods: Optical biometry measurements obtained with the Lenstar LS 900 (Haag-Streit USA Inc, EyeSuite software version i9.1.0.0) were aggregated from 170 patients who had undergone Ortho-K for myopia correction between 5 and 20 years of age. Pre-intervention biometry measurements were compared with follow-up measurements done 6– 18 months after initiation of Ortho-K. Linear mixed models were used to quantify associations in biometry changes with age of intervention allowing for correlation between measurements on two eyes of the same patient.Results: A total of 91 patients were included in the study. Axial length increased through the age of 15.7 ± 0.84 years for Ortho-K patients at our center. The growth curve in our Ortho-K population was comparable to previously published normal growth curves in Wuhan and Germany populations. Corneal thickness and keratometry decreased at a stable rate regardless of age of intervention (− 7.9 μm, 95% CI [− 10.2, − 5.7], p < 0.001).Conclusion: In our population, Ortho-K did not appear to affect the overall trajectory of axial length progression when compared to normal growth curves, despite showing a previously described reduction in corneal thickness. As Ortho-K has been shown to have varying effects that differ from individual to individual, it continues to be important to reassess its effects on new populations to better understand its ideal uses.Keywords: orthokeratology, biometry, pediatrics, axial length, corneal thickness

AIM: To investigate the difference, correlation, and consistency of corneal thickness and the thinnest point position detected by Pentacam HR corneal topography map and RTVue optical coherence tomography(OCT)in patients with keratoconus.METHODS: Cross-sectional comparative study. The corneal curvature map, corneal thickness map, thinnest point position, and thinnest point thickness were detected by Pentacam HR and RTVue OCT. Paired sample t-test was used for data consistent with normal distribution, and paired sample rank sum test was used for data inconsistent with normal distribution. Spearman correlation analysis and Bland-Altman analysis were used for the correlation and consistency of the two measurement methods.RESULTS: A total of 63 patients(105 eyes)with keratoconus were included in this study, including 49 males(77.8%)and 14 females(22.2%), aged 22.24±6.19 years; among them, relevant data of Pentacam HR topographic map: Km was 47.85±4.73D and Kmax was 55.43±8.72D. In measuring central corneal thickness and the thinnest point thickness of keratoconus, the Pentacam HR was 4.70μm and 19.46μm thicker than the mean value measured by RTVue OCT(P0.05). The central corneal thickness and the thinnest point thickness measured by the two devices were highly correlated, the horizontal coordinate of the thinnest point was moderately correlated, and the vertical coordinate of the thinnest point was weakly correlated. Bland-Altman analysis showed that the central corneal thickness, the thinnest point thickness, the horizontal coordinate of the thinnest point, and the vertical coordinate of the thinnest point were 95.2%(100/105)and 93.3%(98/105), 95.2%(100/105), 95.2%(100/105)respectively, which were within the 95% consistency limit, while the consistency ranges were -36.00～+26.62μm, -42.27～+3.36μm, -0.80～+0.84mm, and -1.95～+1.06mm, respectively.CONCLUSION: In keratoconus, the central corneal thickness and the thinnest point thickness measured by Pentacam HR were higher than those measured by RTVue OCT. It is not recommended that the central corneal thickness and the thinnest point thickness measured by the two instruments be interchangeable in clinical use because of the wide range of consistency between the two instruments' results. The position of the thinnest corneal point measured by the two instruments is similar and consistent, so it could be considered to replace the measured values of the two instruments in clinical use.

Purpose: To compare the central corneal thickness (CCT), minimum corneal thickness (MCT) and corneal power measured using the Scheimpflug-Placido device and optical coherence tomography (OCT) in healthy eyes. Study Design: Descriptive observational. Place and Duration of Study: Al-Kindy college of medicine/university of Baghdad, from June 2021 to April 2022. Methods: A total of 200 eyes of 200 individuals were enrolled in this study. CCT and MCT measurements were carried out using spectral-domain optical coherence tomography (Optovue) and a Scheimpflug-Placido topographer (Sirius). The agreement between the two approaches was assessed using Bland-Altman analysis in this study. Results: Mean age was 28.54 ± 6.6 years, mean spherical equivalent of refraction was -3.57 ± 3.35 D. Mean CCT by Optovue, and Sirius were 534.13 ± 27.88 μm, and 540.2 ± 27.85 μm, respectively. Mean CCT differences between them were -6.070 ± 6.593 μm, (p < 0.05). Minimum thickness by Optovue was 526.79 ± 27.81, and by Sirius was 537.44 ± 27.56, mean difference between the two devices was 10.66 ± 6.89, p = 0.00. The net power by OCT was 43.44 ± 1.456, mean K by Sirius was 43.597 ± 1.408, with p = 0.000. Maximum level of agreement between the two devices is -18.99 to 6.85 for CCT, is widest for minimum thickness -24.166 to 2.85 and narrowest for differences between net corneal power by OCT and mean K By Sirius is -0.87 to 1.18. Conclusion: In clinical practice, the two devices cannot be used interchangeably. CCT and keratometry should be evaluated and followed up using the same device. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the thickness profile and the endothelial cell density (ECD) of donated corneas maintained in Optisol-GS with those preserved in Sinasol over seven days. Methods: Twenty paired donor corneas were received from the Central Eye Bank of Iran. After recording the osmolarity of each medium, one of each of the cornea pairs was preserved in either Optisol-GS or Sinasol media. Then, slit-lamp biomicroscopy and specular microscopic examinations were performed at the baseline and on day seven. Visante optical coherence tomography (V-OCT) was also performed at 1 hour (h), 24h, 72h, and one week post-preservation. The specular microscopic and V-OCT values were then compared between the two groups. Results: The mean osmolarity of the Sinasol group was significantly less than the Optisol- GS group (296 vs. 366 mOsm/L, P = 0.0008). The mean central corneal thickness at the measurement points was comparable between the two groups. However, the increase of thickness one week post-preservation in the Sinasol group was remarkably lower than those in the Optisol-GS group (P = 0.027). The mean ECD was comparable between the groups at the baseline and on day seven. However, the mean change of ECD from baseline to day seven was considerably higher in the Optisol-GS group than in the Sinasol group (P = 0.019). Conclusion: Corneal storage in Sinasol over seven days provides better and superior maintenance and preservation of corneal tissue deturgescence and a lower rate of ECD loss over Optisol-GS. [ABSTRACT FROM AUTHOR]

To compare the central corneal thickness (CCT) treated with small incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), or laser-assisted subepithelial keratomileusis (LASEK) for myopia correction. This was a retrospective case series study. Patients who had completed 1-year follow-up after receiving SMILE, FS-LASIK, or LASEK at our hospital from January 2019 to July 2021 were included. Pentacam pachymetry was performed to measure the CCT. The predicted CCT reduction was obtained through laser platform. The measured CCT reduction was defined as the difference between the preoperative and postoperative CCT using Pentacam pachymetry. There were 100 eyes treated by SMILE, 100 eyes by FS-LASIK, and 100 eyes by LASEK. There was a significant difference in predicted CCT reduction among the three surgeries (P < 0.001), but no significant difference in measured CCT reduction postoperatively (PGroup = 0.373). At 1 year postoperatively, the CCT reduction was overestimated by 17.85 ± 5.36 µm in the SMILE group, underestimated by 4.31 ± 7.08 µm in the FS-LASIK group, and underestimated by 7.60 ± 8.28 µm in the LASEK group (PGroup < 0.001, PTime < 0.001). In the FS-LASIK group, the difference between predicted and measured CCT reduction was not related to the predicted CCT reduction (P = 0.095). The laser platform may overestimate the CCT reduction for SMILE and underestimate it for FS-LASIK and LASEK. FS-LASIK has a much higher level of accuracy in CCT reduction, which is not influenced by refractive correction. [ABSTRACT FROM AUTHOR]

This study investigated the prevalence of pigmentary keratitis (PK) in Pug-breed dogs and described the ocular surface characteristics associated with this disease. A total of 219 eyes from 110 dogs were examined, with 94.5% of them affected by PK. Age, previous ocular diseases, corneal vascularization, and corneal sensitivity were significantly associated with the presence of PF and the severity of corneal pigmentation. The study also found that low tear production and blinks incomplete with tear signs, as well as reduced corneal sensitivity, were linked to more severe forms of corneal pigmentation. The Tear Ferning Test (TFT) was identified as a valuable tool for evaluating tear quality in dogs, with worse test results indicating a higher risk of severe PK. A lower mean Tear Break-Up Time (TBUT) test was observed in dogs with PK. Additionally, the study observed a statistically significant difference in corneal thickness between the nasal and temporal zones, with the nasal zone being thicker. It was also suggested that sex and fertility status may influence the incidence of PK and the severity of corneal pigmentation. Overall, these findings provide insight into the underlying causes of PK in Pugs and can inform future treatment strategies for this breed.

Purpose: To evaluate the effects of topical 0.1% cyclosporin treatment on topographic, pachymetric, and densitometric maps of the cornea in severe pediatric cases of vernal keratoconjunctivitis (VKC). Materials and Methods: Thirty eyes of 30 pediatric patients with severe VKC were included in this study. The symptom and sign scores of these VKC patients were calculated and examinations were performed before and 6 months after topical 0.1% cyclosporin treatment. Pre and post-treatment values of flat keratometry (K1), steep K (K2), maximum K (Kmax), central corneal thickness (CCT), corneal volume (CV), anterior, center, posterior and total densitometry values (in two corneal concentric zones: 0-2-mm and 2-6-mm) were compared. Results: The mean CCT and CV values decreased from 546.85±28.20 to 539.85±25.21 µm and 60.9±3.2 to 60.1±3.0 mm3, respectively (p<0.001, both of them). Keratometry values (K1, K2, and Kmax) did not change after treatment (p:0.787, p:0.464 and p:0.963, respectively). The anterior, center, and total densitometry values in the 0-2-mm and 2-6-mm concentric corneal zones were significantly decreased after treatment (p<0.001, for all values). Conclusions: In severe pediatric VKC patients, topical cyclosporine therapy provides reduction in densitometric (increased corneal transparency), CCT and CV values and also improves symptoms and findings. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to assess the normative macular choroidal thickness (ChT) in healthy children with spectral domain optical coherence tomography (SD‐OCT) and study its correlations with age, intraocular pressure, axial length, corneal thickness, cup‐to‐disc ratio, and spherical equivalent. Methods: This study recruited 89 healthy children. Macular ChT was measured in five locations, subfoveal, 1500 μm and 3000 μm nasal, and temporal to the fovea via the Optopol REVO80® SD‐OCT. Results: The mean age was 11.17 years. The mean subfoveal ChT was 332.33 ± 73.07 μm, ChT 1500 μm nasal to the fovea; 281.19 ± 66.67 μm, ChT 1500 μm temporal to the fovea; 293.25 ± 71.11 μm, ChT 3000 μm nasal to the fovea; 219.55 ± 67.4 μm, ChT 3000 μm temporal to the fovea; 264.31 ± 70.8 μm. A correlation of subfoveal ChT was not observed with the variables. Conclusions: This study illustrates the normative pediatric macular ChT profile. [ABSTRACT FROM AUTHOR]

Objective: To evaluate anterior segment parameters in obese children. Methods: Fifty-five obese and 30 control group children subjects participated. All participants and the control group were examined and anthropometric measurements were made. The measurements of fasting blood glucose (FBG), systolic blood pressure (SBP) triglyceride (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), lowdensity lipoprotein-cholesterol (LDL-C), and insulin values were performed. The homeostasis model assessment of insulin resistance (HOMA IR) was calculated. Each participant underwent a detailed ophthalmic examination and intraocular pressure (IOP), central corneal thickness (CCT), anterior chamber depth (ACD) and lens thickness (LT) were measured. Results: The gender distribution of the groups was similar (p=0.893). The mean of CCT and LT were significantly higher in the obese group (572.9 ± 14.5 vs. 559.5 ± 10.1 µm, p=0.001; 3.6 ± 0.14 vs. 3.48 ± 0.25 mm, p=0.007). No significant difference was found between the obese and control groups in terms of other parameters. Body mass index (BMI) and waist circumference (WC) had a significant negative correlation with LT control groups. The obese group showed a significant positive correlation between IOP and TG (r=0.276, p=0.042), and a significant negative correlation with HDL-C (r=-0.273, p=0.043). In the control group, there was a significant positive correlation between IOP and BMI (r=0.389, p=0.034), WC (r=0.497, p=0.005), HOMA-IR (r=0.384, p=0.036), Insulin (r=0.407, p=0.026), and a significant negative correlation with TC (r=-0.511, p=0.004). A significantly positive correlation between ACD and LDL-C (r=0.371, p=0.043) and a significantly negative correlation between HOMA-IR in the control group were detected (r=-0.682, p=0.000). Conclusions: The obese group had higher CCT and LT than the control groups. [ABSTRACT FROM AUTHOR]

Purpose: To observe the changes in corneal thickness during phacoemulsification cataract surgery and to analyze the influencing factors. Methods: One hundred two patients (102 eyes) with cataracts undergoing phacoemulsification cataract surgery at Shandong Eye Hospital between July and October 2021 were included. Intraoperative OCT was applied to capture real-time images preoperatively, before and after ultrasonic emulsification, at the end of irrigation aspiration and the end of surgery. Then, the corneal thickness at the above time points was measured using Photoshop software. Results: The corneal thickness of 102 cataract patients was 511.79 ± 31.46 μm before operation and 512.71 ± 31.51 μm at the beginning of phacoemulsification, which increased by 0.91 ± 1.48 μm (0.2%). At the end of ultrasonic emulsification, the corneal thickness was 521.58 ± 32.75 μm and 8.87 ± 8.71 μm (1.7%) thicker than that before the procedure. After irrigation aspiration, the corneal thickness reached 528.09 ± 33.87 μm, which increased by 6.52 ± 6.38 μm (1.3%) compared with that of the previous step. At the end of the operation, the corneal thickness was 539.19 ± 33.88 μm, 11.09 ± 10.92 μm, and 27.37 ± 13.64 μm thicker than that of the previous step and the preoperative thickness, respectively, with an overall increase of 5.3%. The differences were statistically significant at all time points (all P < 0.001). Correlation analysis showed that postoperative corneal thickness changes were correlated with age, cataract lens nuclear grade, actual phacoemulsification time (APT), effective phacoemulsification time (EPT), average phacoemulsification energy (APE), total surgery time (TST), cell density (CD), maximum cell area (MAX), and cell area standard deviation (SD) (all P < 0.05), while the changes in thickness were not correlated with gender, cell area coefficient of variation (CV), percentage of hexagonal cells (6A), average cell area (AVE), or minimum cell area (MIN) (all P > 0.05). Conclusions: During phacoemulsification cataract surgery, corneal thickness gradually increases in real time with the increase of perfusion pressure and intraocular manipulation time. The real-time magnitude of intraoperative corneal thickness change is closely related to lens nucleus hardness, corneal endothelial cell density, ultrasound energy, and time for emulsification. [ABSTRACT FROM AUTHOR]