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Purpose: To investigate the efficacy and safety of a modified dual-incision ophthalmic viscosurgical device-free (OVD-free) method for implantable collamer lens (ICL) implantation in high myopic eyes. Methods: A total of 68 participants were enrolled in this prospective randomized clinical trial, including 33 in the OVD-free group and 35 in the standard group. Operation time and intraocular pressure (IOP) at 2 hours postoperatively were recorded. Visual acuity, refractive power, IOP, corneal endothelium parameters, and anterior segment parameters were assessed at 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. Postoperative subjective visual quality at 3 months was recorded through a Quality of Vision (QoV) questionnaire. Results: No significant differences in visual acuity, refractive outcomes, and corneal endothelial parameters were found, while the operation time was significantly shorter in the OVD-free group. Both groups showed a significant increase in IOP at 2 hours after surgery, but the increase in the OVD-free group was significantly smaller than that in the standard group. In addition, the frequency of ring-shaped dysphotopsia in the OVD-free group (15.15%) was significantly lower than that in the standard group (40%), and the severity and annoyance of this symptom were also significantly lower in the OVD-free group. Conclusion: The modified OVD-free ICL implantation is a safe, effective, and predictable method for myopia correction, which could be a better choice for short surgery time, better subjective visual perception, and low occurrence of IOP elevation.

Purpose: To investigate the efficacy and safety of a modified dual-incision ophthalmic viscosurgical device-free (OVD-free) method for implantable collamer lens (ICL) implantation in high myopic eyes. Methods: A total of 68 participants were enrolled in this prospective randomized clinical trial, including 33 in the OVD-free group and 35 in the standard group. Operation time and intraocular pressure (IOP) at 2 hours postoperatively were recorded. Visual acuity, refractive power, IOP, corneal endothelium parameters, and anterior segment parameters were assessed at 1 day, 1 week, 1 month, 3 months, and 6 months postoperatively. Postoperative subjective visual quality at 3 months was recorded through a Quality of Vision (QoV) questionnaire. Results: No significant differences in visual acuity, refractive outcomes, and corneal endothelial parameters were found, while the operation time was significantly shorter in the OVD-free group. Both groups showed a significant increase in IOP at 2 hours after surgery, but the increase in the OVD-free group was significantly smaller than that in the standard group. In addition, the frequency of ring-shaped dysphotopsia in the OVD-free group (15.15%) was significantly lower than that in the standard group (40%), and the severity and annoyance of this symptom were also significantly lower in the OVD-free group. Conclusion: The modified OVD-free ICL implantation is a safe, effective, and predictable method for myopia correction, which could be a better choice for short surgery time, better subjective visual perception, and low occurrence of IOP elevation. [ABSTRACT FROM AUTHOR]

Research conducted over the years has established that artificial light at night (ALAN), particularly short wavelengths in the blue region (~400–500 nm), can disrupt the circadian rhythm, cause sleep disturbances, and lead to metabolic dysregulation. With the increasing number of people spending considerable amounts of time at home or work staring at digital screens such as smartphones, tablets, and laptops, the negative impacts of blue light are becoming more apparent. While blue wavelengths during the day can enhance attention and reaction times, they are disruptive at night and are associated with a wide range of health problems such as poor sleep quality, mental health problems, and increased risk of some cancers. The growing global concern over the detrimental effects of ALAN on human health is supported by epidemiological and experimental studies, which suggest that exposure to ALAN is associated with disorders like type 2 diabetes, obesity, and increased risk of breast and prostate cancer. Moreover, several studies have reported a connection between ALAN, night-shift work, reduced cognitive performance, and a higher likelihood of human errors. The purpose of this paper is to review the biological impacts of blue light exposure on human cognitive functions and vision quality. Additionally, studies indicating a potential link between exposure to blue light from digital screens and increased risk of breast cancer are also reviewed. However, more research is needed to fully comprehend the relationship between blue light exposure and adverse health effects, such as the risk of breast cancer.

Research conducted over the years has established that artificial light at night (ALAN), particularly short wavelengths in the blue region (~400--500 nm), can disrupt the circadian rhythm, cause sleep disturbances, and lead to metabolic dysregulation. With the increasing number of people spending considerable amounts of time at home or work staring at digital screens such as smartphones, tablets, and laptops, the negative impacts of blue light are becoming more apparent. While blue wavelengths during the day can enhance attention and reaction times, they are disruptive at night and are associated with a wide range of health problems such as poor sleep quality, mental health problems, and increased risk of some cancers. The growing global concern over the detrimental effects of ALAN on human health is supported by epidemiological and experimental studies, which suggest that exposure to ALAN is associated with disorders like type 2 diabetes, obesity, and increased risk of breast and prostate cancer. Moreover, several studies have reported a connection between ALAN, night-shift work, reduced cognitive performance, and a higher likelihood of human errors. The purpose of this paper is to review the biological impacts of blue light exposure on human cognitive functions and vision quality. Additionally, studies indicating a potential link between exposure to blue light from digital screens and increased risk of breast cancer are also reviewed. However, more research is needed to fully comprehend the relationship between blue light exposure and adverse health effects, such as the risk of breast cancer. [ABSTRACT FROM AUTHOR]

According to World Health Organization (WHO), 314 million individuals worldwide suffer from some degree of vision impairment. Yoga is an effective intervention for the purification and preparation of the body. The leading cleaning practices such as yoga postures, breathing control, and meditation, among others. These techniques include a yogic visual concentration technique known as Trataka. According to certain studies, yogic visual concentration improves eyesight. However, the immediate effect of trataka on visual acuity in adolescents with the visually impaired has not been investigated. Purpose. The present study investigated the effect of 6 weeks of trataka training on visual acuity in visually impaired adolescents. Material & Methods. The study used a single group, before/after design, with ten visually challenged adolescents (Mage=16.5 years; SD=1.5; range 15-18 years) participating in a 6-week trataka training. In clinical settings, the Snellen chart is the most used tool for determining a participant's level of visual acuity. Results. The outcome score for left eyesight (44.44 per cent) and right eyesight (50.43 per cent) improved significantly. Furthermore, paired t-test findings revealed significant improvement in both left eyesight (p

Correction of chromatic and spherical aberration using different hybrid multifocal intraocular lenses (MIOLs) was investigated. In this study, hybrid multi-focal length MIOLs of different types; hologram/refractive (H/R); hologram/diffractive (H/D); refractive/hologram (R/H); diffractive/hologram (D/R); refractive/diffractive (R/D); and diffractive/refractive (D/R) were implanted. Visual performance was assessed in a white and green light, with a pupil diameter of 4 mm and a field of view of 5 degrees. Chromatic focal shift (LCA) and longitudinal spherical aberrations (LSA) were measured and compared. There was an average improvement in visual performance associated with the correction with the longitudinal chromatic aberration of 45-74% and longitudinal aberration of 48-65% for all hybrid MIOL implanted within the eye model as compared with that of the healthy eye model. Similarly, the average polychromatic MTF and PSF measurements improved in white light. Results show that the vision for all hybrid MIOLs implanted in the eye is better than the healthy eye model. All hybrid-hologram and hybrid(R/D & D/R) MIOLs proposed model sharp vision was achieved within range (25-108 cm). A hybrid MIOLs model [(R/D) and (D/H)] {a refractive or diffractive posterior surface and diffractive or hologram surface before surface, respectively} provide the best vision performance (i.e. maximum aberration correction and better MTF). [ABSTRACT FROM AUTHOR]

The most effective treatment for cataracts is to remove the cloudy crystalline natural lens and implant an intraocular lens (IOL) in its place. These refractive (IOL) provide the same focusing as do the natural lens. Two refractive IOLs are designed and analyzed in this paper—these IOL are made of (PMMA, and Acrylic). The quality of the retinal image is analyzed and compared with the healthy eye, which is based on the (Liou-Brennan) eye model) LBEM). Polychromatic Point Spread Function (PSF), Modulation Transfer Function (MTF), spot diagram, Encircled Energy (EE), and monochromatic aberration are used as acceptable criteria within the Zemax software.

Abstract Background Aiming at spectacle independence, conventional pseudophakic monovision has been widely used in myopia patients with bilateral monofocal intraocular lens implantation. However, the crossed monovision, which is to correct the dominant eye for near vision and the non-dominant eye for distant vision, has been mentioned preferable for high myopic cataract patients by some studies. We have conducted this study to compare clinical results to assess the feasibility of conventional and crossed monovision for high myopic pseudophakic patients by comparing patient satisfaction, visual function and spectacle independence. Method Forty-sixth high myopia patients were divided into two groups: 22 in crossed monovision group with patients whose refraction targeted to − 2.00 diopters (D) in the dominant eye and − 0.50D in the non-dominant eye; 24 in conventional monovision group with patients whose refraction targeted to − 0.50D in the dominant eye and − 2.00D in the non-dominant eye. Binocular uncorrected distance visual acuity (BUDVA), binocular uncorrected near visual acuity (BUNVA), binocular corrected distant visual acuity (BCDVA), binocular corrected near visual acuity (BCNVA), contrast visual acuity and stereoacuity were examined at postoperative 2 weeks, 1 month and 3 months. Questionnaires were completed by patients 3 months after binocular surgery to evaluate patients’ satisfaction and spectacle independence. Results The conventional monovision and the crossed monovision group showed no significant differences of mean BUDVA, BUNVA, BCDVA, BCNVA 2 weeks, 1 month or 3 months postoperatively (P > 0.05). There was no difference in the bilateral contrast sensitivity or stereoscopic function between the convention conventional and crossed monovision groups (P > 0.05). Patient satisfaction with near and distant vision, as well as spectacle dependence did not differ significantly between the two groups (P > 0.05). Conclusion Crossed pseudophakic monovision exhibited similar visual function when compared with conventional monovision technique, which indicates that it is an effective option to improve the visual functionality and quality of life for high myopic patients who considering bilateral cataract surgery. Trial registration The Institutional Review Board and Ethics committee of the First Affiliated Hospital of Chongqing Medical University, Chongqing, China. The trial registration was submitted in September 2018 and passed on March 18, 2020, and the registration number is: ChiCTR2000030935 .

Dry eye disease (DED) is increasingly prevalent, resulting in higher morbidity among children. This study evaluates the impact of DED severity on visual quality using double-pass technology, focusing on dynamic observation of the ocular light scatter in pediatric DED cases. In this non-interventional, cross-sectional study, a mild DED group (37 cases, 37 eyes), a moderate DED group (40 cases, 40 eyes), and a control group of healthy children (35 cases, 35 eyes) were examined. Measurements included the Schirmer I test, tear film break-up time (BUT), and vision-related quality of life assessments using the Modified Ocular Surface Disease Index (OSDI) questionnaires. Participants underwent visual quality analysis using double-pass technology, which measured the modulation transfer function cut-off frequency value, Strehl ratio, objective scatter index (OSI), and OQAS-II value (OQAS-II value 100%, OQAS-II value 20%, and OQAS-II value 9%) under natural conditions. Additionally, dynamic changes in OSI post-blinking, Tear film mean-OSI , and the corresponding standard deviation OSI were recorded. Statistically significant differences were observed among the groups in modulation transfer function cutoff, Strehl ratio, OSI, OQAS-II value 100 %, OQAs-II value 20 %, OQAs-II value 9 %, tear film mean OSI, and standard deviation OSI (P < 0.05). As DED severity increased, tear film mean OSI significantly rose, while modulation transfer function cutoff, strehl ratio, OQAS-II value 100 %, OQAS-II value 20 %, OQAS-II value 9 % notably declined. All optical quality parameters were correlated with BUT, with no association observed with age, sex, or Schirmer I test. Dual-channel technology objectively assesses visual quality in pediatric DED, demonstrating that tear film scattering significantly affects retinal imaging and visual quality in children with DED. [ABSTRACT FROM AUTHOR]

Higher Order Aberrations (HOAs) are complex refractive errors in the human eye that cannot be corrected by regular lens systems. Researchers have developed numerous approaches to analyze the effect of these refractive errors; the most popular among these approaches use Zernike polynomial approximation to describe the shape of the wavefront of light exiting the pupil after it has been altered by the refractive errors. We use this wavefront shape to create a linear imaging system that simulates how the eye perceives source images at the retina. With phase information from this system, we create a second linear imaging system to modify source images so that they would be perceived by the retina without distortion. By modifying source images, the visual process cascades two optical systems before the light reaches the retina, a technique that counteracts the effect of the refractive errors. While our method effectively compensates for distortions induced by HOAs, it also introduces blurring and loss of contrast; a problem that we address with Total Variation Regularization. With this technique, we optimize source images so that they are perceived at the retina as close as possible to the original source image. To measure the effectiveness of our methods, we compute the Euclidean error between the source images and the images perceived at the retina. When comparing our results with existing corrective methods that use deconvolution and total variation regularization, we achieve an average of 50% reduction in error with lower computational costs. [ABSTRACT FROM AUTHOR]

Objectives: To compare early subjective and objective vision quality of postoperative patients undergoing phacoemulsification cataract surgery combined with implantation of refractive segmental multifocal intraocular lens (MIOL) SBL-3 and apodized diffractive MIOL SN6AD1. Methods: As a prospective study, it enrolled 53 patients (53 eyes) to undergo phacoemulsification cataract surgery combined with MIOL implantation. According to differences in MIOL implanted, patients were divided into a SBL-3 group (25 eyes) and a SN6AD1 group (28 eyes). Ophthalmological evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, uncorrected intermediate (UIVA) and near (UNVA) visual acuities, distance-corrected intermediate (DCIVA) and near (DCNVA)visual acuities and corrected near(CNVA) visual acuity, contrast sensitivity, modulation transfer function (MTF) and high order aberration (4 mm pupil diameter) at three months postoperatively. Moreover, a questionnaire survey was carried out to assess near spectacle independence, patient satisfaction and symptoms of visual disturbance. Results: At three months after surgery, UIVA and UNVA in the SBL-3 group are statistically significantly superior to those of the SN6AD1 group (P<0.05). There was statistical difference in contrast sensitivity at four spatial frequencies (3, 6, 12, 18cycles/degree) under mesopic conditions and mesopic conditions with glare (P<0.05). The total ocular high order aberration, coma and trefoil were statistically significantly larger in the SBL-3 group than in the SN6AD1 group with 4.0 mm pupil diameters (P<0.05). Statistical differences were found in the MTF at spatial frequencies of 5, 10 and 15 cycles/degree between the groups. There were no significant differences in spectacle independence, patient satisfaction and visual disturbance between the groups (P>0.05). Conclusions: Both the two multifocal intraocular lens provided an excellent level of quality of vision three months postoperatively. However, the application effect of SBL-3 MIOL is superior to that of SN6AD1 MIOL as far as intermediate vision, near vision and contrast sensitivity are concerned. [ABSTRACT FROM AUTHOR]

To improve visual quality and embedding rate of existing difference expansion reversible image watermarking algorithm, a reversible image watermarking algorithm was proposed based on bit plane decomposition. The carrier image was decomposed by bit plane, and the low 6 bit planes were combined together to form a new image. The new image was divided into non overlapping blocks. The entropy of each block was calculated, and the image blocks with small entropy were selected to embed into watermark by the generalized difference expansion algorithm. The overflow graph and the relevant auxiliary information were embedded into the selected original image blocks of the corresponding image blocks with large entropy by difference quantization method. The 8 bit gray scale images of Lena and Barbara were used to test the reversible watermarking algorithm. The results show that the algorithm has high embedding rate and high visual quality, and the original image can be fully restored. When Lena is used as host image, the payload reaches 0.93 bpp. Compared with other algorithms, the watermark embedding rate is improved with good visual quality. [ABSTRACT FROM AUTHOR]

Highlights: [•] We compare wave optical simulations of multifocal intraocular lenses in different eye models. [•] Prototypes of bifocal and trifocal intraocular lenses were manufactured and characterized. [•] Field tracing will become an important tool for future intraocular lens development. [•] Vision quality depends on the eye model applied for intraocular lens design. [ABSTRACT FROM AUTHOR]

Objectives: To compare early subjective and objective vision quality of postoperative patients undergoing phacoemulsification cataract surgery combined with implantation of refractive segmental multifocal intraocular lens (MIOL) SBL-3 and apodized diffractive MIOL SN6AD1., Methods: As a prospective study, it enrolled 53 patients (53 eyes) to undergo phacoemulsification cataract surgery combined with MIOL implantation. According to differences in MIOL implanted, patients were divided into a SBL-3 group (25 eyes) and a SN6AD1 group (28 eyes). Ophthalmological evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, uncorrected intermediate (UIVA) and near (UNVA) visual acuities, distance-corrected intermediate (DCIVA) and near (DCNVA)visual acuities and corrected near(CNVA) visual acuity, contrast sensitivity, modulation transfer function (MTF) and high order aberration (4 mm pupil diameter) at three months postoperatively. Moreover, a questionnaire survey was carried out to assess near spectacle independence, patient satisfaction and symptoms of visual disturbance., Results: At three months after surgery, UIVA and UNVA in the SBL-3 group are statistically significantly superior to those of the SN6AD1 group (P>0.05). There was statistical difference in contrast sensitivity at four spatial frequencies (3, 6, 12, 18cycles/degree) under mesopic conditions and mesopic conditions with glare (P>0.05). The total ocular high order aberration, coma and trefoil were statistically significantly larger in the SBL-3 group than in the SN6AD1 group with 4.0 mm pupil diameters (P>0.05). Statistical differences were found in the MTF at spatial frequencies of 5, 10 and 15 cycles/degree between the groups. There were no significant differences in spectacle independence, patient satisfaction and visual disturbance between the groups (P>0.05)., Conclusions: Both the two multifocal intraocular lens provided an excellent level of quality of vision three months postoperatively. However, the application effect of SBL-3 MIOL is superior to that of SN6AD1 MIOL as far as intermediate vision, near vision and contrast sensitivity are concerned., Competing Interests: Conflicts of Interest: None., (Copyright: © Pakistan Journal of Medical Sciences.)

Background: Laser-Assisted in situ Keratomileusis (LASIK) can induce corneal aberrations that can impact vision and patient satisfaction. Recent developments in laser technologies have helped minimise these aberrations., Objective: To assess the quality of vision and change in Higher-Order Aberrations (HOAs) following wavefront-optimized LASIK in low-myopic astigmatic patients., Methods: LASIK was performed on a total of 76 eyes in patients with myopia <4.0 D and cylinder <2.0 D using the WaveLight® EX500 excimer and FS200 femtosecond laser platform. Visual acuity, contrast sensitivity and HOAs were measured at 1 and 3 months postoperatively and compared to preoperative values. Subjective quality of vision was assessed pre- and postoperatively using a VF14 questionnaire., Results: Mean postoperative Spherical Equivalent (SE) was -0.09 ± 0.26 µm with 95% of patients within ± 0.5 D of attempted SE. Postoperative uncorrected distance visual acuity was 20/20 or better for 96% of patients. Contrast sensitivity increased against horizontal and vertical gratings at all spatial frequencies except for vertical gratings at 18 cycles/degree. Spherical aberration and total HOA increased by 0.085 µm and 0.13 µm respectively. The mean VF14 score increased from 89.2 ± 16.7% to 99 ± 1.4% postoperatively., Conclusion: LASIK performed using the WaveLight® EX500 excimer and WaveLight® FS200 laser platform provided improved contrast sensitivity and visual acuity with minimal introduction of HOAs, making it a suitable platform for low myopic astigmatic patients.

Purpose: To compare and analyze changes in vision quality, subjective symptoms, and psycho-social satisfaction in keratoconus and myopic patients following the wearing of contact lenses., Methods: This study enrolled 25 keratoconus and 25 myopic patients with corrected vision over 0.8 according to the Snellen chart due to treatment with contact lenses. Patients were surveyed prior to the wearing of contact lenses, and again after three months of contact lens usage with a questionnaire about quality of vision and life. The changes in visual function, visual symptoms, and psycho-social well-being before and after contact lens usage were analyzed., Results: The keratoconus patients' overall degree of satisfaction was higher than the overall degree of satisfaction of myopic patients, and the motivation for contact lens usage and purpose of contact lens treatment were different in the two groups. Keratoconus patients experienced greater changes in satisfaction, particularly in satisfaction during night activities, short-distance work, and the reading of fine print. Furthermore, they experienced fewer dry eye symptoms but greater foreign body sensations than patients with myopia following treatment with contact lenses. No statistically significant differences in social role functions existed between the two groups. Keratoconus patients had a lower expectation of visual acuity recovery before treatment with contact lenses (Mann-Whitney U-test, p = 0.049) compared to myopic patients, and more anxiety about vision loss following treatment (Wilcoxon signed-rank test, p = 0.018) compared to their level of anxiety about vision loss before treatment with contact lenses., Conclusions: Although the same treatment was applied, keratoconus and myopic patients experienced different types of discomfort and areas of improvement in contact lens corrected vision. Therefore, not only corrected vision, but also subsequent improvement and discomfort outcomes should be considered by patients when choosing contact lens treatment. For patients with mild keratoconus, contact lens treatment may be an efficacious first treatment modality., Competing Interests: No potential conflict of interest relevant to this article was reported., (© 2017 The Korean Ophthalmological Society)

Purpose: To assess the functional impact of the severity of dry eye on the quality of vision by measuring an Objective Scatter Index (OSI) using double pass aberrometry., Patients and Methods: Twenty-eight patients (56 eyes) with dry eye syndromes of varying severity participated in this study. A double-pass aberrometer was used to measure the dynamic changes in the OSI for 20 seconds. The mean and standard deviations of the OSI and the number of blinks occurring during the examination were compared as a function of the clinical severity of dry eye disease., Results: The mean OSI increased with the severity of dry eye syndrome with a significant difference for stages 3 (P<0.01) and 4 (P<0.001) compared to stages 1 and 2, without a significant difference based on age (P>0.8) or visual acuity (P>0.2). Standard deviation of the OSI also increased with the severity of dry eye disease, with a significant difference for stages 3 (P<0.01) and 4 (P<0.0001) compared to stages 1 and 2, with no significant increase in the number of blinks (P>0.2). The values of the OSI standard deviation represented the dynamic nature of aberrometric changes related to the instability of the tear film., Conclusion: Quality of vision of patients deteriorated in relation to the severity of their dry eye. The analysis of OSI standard deviation appears to be an objective way to assess the intensity of subjective visual disturbances reported by patients with dry eye syndrome. It also provides a new tool to assess the severity of damage to the ocular surface., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)