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Purpose: To compare central corneal thickness (CCT) measured by standard ultrasound pachymetry (USP), and three non-contact devices in healthy eyes. Methods: A cross-sectional study of CCT measurement in 52 eyes of 52 healthy volunteers was done by a single examiner at Ocular Surface and Contact Lens Laboratory. Three consecutive measurements were done by standard USP, non-contact tono-pachymeter, Pentacam corneal topographer, and Anterior Segment Optical Coherence Tomography (AS-OCT). The mean values were used for assessment. The results were compared using multivariate ANOVA, linear regression, and Pearson correlation. Agreement among the devices was analyzed using mean differences and Bland–Altman analysis with 95% limits of agreement (LoA). Finally, reliability was analyzed using intraclass correlation coefficient (ICC). Results: Mean CCT by ultrasound pachymeter, tono-pachymeter, corneal topographer and AS-OCT were 558.9 ± 31.2 µm, 525.8 ± 43.1 µm, 550.4 ± 30.5 µm, and 545.9 ± 30.5 µm respectively. There was a significant positive correlation between AS-OCT and USP (Pearson correlation = 0.957, p < 0.001), corneal topography and USP (Pearson correlation = 0.965, p < 0.001), and corneal topography and AS-OCT (Pearson correlation = 0.965, p < 0.001). There was a lower correlation between CT-1P tono-pachymeter and the other three modalities. Intraclass correlation coefficients show an excellent reliability between pairs except for CT-1P against the other three instruments that were found moderate. Conclusions: CT-1P tono-pachymeter underestimates CCT measurements compared to Scheimpflug system, AS-OCT device, and USP. Mean CCT among USP, Pentacam and AS-OCT were comparable and had significant linear correlations. In clinical practice, these three modalities could be interchangeable in healthy patients, info:eu-repo/semantics/publishedVersion

Purpose: to compare the rebound tonometer ICare® (RT) with the Goldmann applanation tonometer (GAT) in cataract surgery and to assess the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements. Design: retrospective, comparative study. Methods: a total of 472 patients underwent IOP measurement using RT (time 0 = RTa). GAT IOP measurement was performed 5 minutes later, followed by a second RT IOP measurement after other 5 minutes (RTa + 10 min = RTb). CCT was obtained by ultrasound pachymetry. In 106 patients IOP was measured by means of RT and GAT before clear corneal cataract surgery (RT1 and GAT1) and at one day postoperatively (RT2 and GAT2). Results: RT IOP values > 5 mmHg were overestimated, while RT IOP values < 15 mmHg were underestimated. Every 100 µm of CCT an increase of 0.97 mmHg and 0.33 mmHg was found for RT and GAT respectively. The difference between RT1 and RT2, GAT1 and GAT2, RT1 and GAT1 was not statistically significant; while the difference between RT2 and GAT2 was statistically significant (p < 0.04). The difference between RTa and RTb was not statistically significant whereas the difference between RTa and GAT and RTb and GAT was statistically significant (p < 0.001). Conclusion: our results showed a good agreement between measurements obtained with RT and GAT in pre and postoperative cataract surgery, although a significant statistically difference was found between RT and GAT measurements performed postoperatively. Moreover, CCT is a parameter to be considered for the IOP measurement, especially for values obtained with RT.

WOS: 000444817100007 PubMed ID: 29509052 Background: To determine the agreement of central corneal thickness (CCT) measurements taken with ultrasonic pachymetry (USP), spectral domain optical coherence tomography (SD-OCT) and noncontact specular microscopy (NSM). Methods: A prospective, observational, cross-sectional study was performed in the outpatient ophthalmology clinic. CCT was measured in a total of 147 eyes of 147 consecutive healthy patients with USP, NSM, and SD-OCT. Same examiner performed all examinations. Bland-Altman plots were used to evaluate the agreement between instruments. Results: The average CCT values obtained by USP, NSM, and SD-OCT were 555 +/- 37 mu m, 554 +/- 34 mu m, and 546 +/- 34 mu m, respectively. There was a strong correlation between instruments: USP with SD-OCT (r = 0.937, p

ResumenObjetivoComparar los valores de grosor corneal central obtenidos mediante el tomógrafo de cámara de Scheimpflug con anillos de plácido (Sirius®), y la paquimetría ultrasónica; y conocer la repetibilidad intraobservador de ambos equipos.Material y métodosSe realizaron estudios de grosor corneal central con ambos equipos en 30 personas sanas. Para evaluar la repetibilidad, se realizaron 3 mediciones para cada individuo con cada equipo y se evaluó el coeficiente de variación, la desviación estándar y el coeficiente de correlación intraclase. Para conocer la concordancia entre ambos equipos, se calculó la diferencia de medias con la t de Student pareada y se realizaron gráficas de Bland y Altman.ResultadosPara el equipo Sirius®, el coeficiente de variación fue del 0.291% y para el paquímetro ultrasónico del 0.238%. La desviación estándar fue 0.123μm y 0.101μm para el Sirius® y el paquímetro ultrasónico respectivamente, y el coeficiente de correlación intraclase fue mayor de 0.95 en todas las mediciones. El paquímetro ultrasónico midió sistemáticamente valores más altos y estadísticamente significativos que el Sirius® (media 543.867 vs. 558.267μm, Sirius® y paquímetro ultrasónico respectivamente), sin embargo, esta diferencia no es clínicamente significativa.ConclusionesEn la evaluación de córneas normales, la medición del grosor corneal central con ambos equipos mostró una alta repetibilidad y adecuada concordancia. Aunque la medición del grosor corneal central fue sistemáticamente más baja con el Sirius® que con el paquímetro ultrasónico, esta diferencia carece de significación clínica.AbstractObjectiveTo assess the repeatability and comparability of the central corneal thickness measurements obtained from a novel Scheimpflug camera with a Placido-disc topographer (Sirius®) and ultrasound pachymetry.Material and methodsIn a sample of thirty unoperated eyes of healthy subjects, the central corneal thickness was analyzed by a single examiner using the Sirius® and the ultrasound pachymeter. Repeatability of three sets of measurements from each device were evaluated using the coefficient of variation, standard deviation, and intraclass correlation coefficient. T-test with Bonferroni adjustment and Bland and Altman plots were used to assess agreement between devices.ResultsFor the Sirius® the coefficient of variation was 0.291%, and for the ultrasound pachymeter was 0.238%. The standard deviation was 0.123μm and 0.101μm for Sirius® and US respectively and the intraclass correlation coefficient was higher than 0.95 in all measurements. Ultrasound pachymetry systematically yielded higher values and statistically significant (mean 543.867 vs 558.267μm Sirius® and ultrasound pachymeter respectively), but the difference was not clinically significant.ConclusionIn the assessment of normal corneas, central corneal thickness measured with both devices showed high repeatability and good agreement. Even though central corneal thickness measurements obtained by Sirius® were systematically lower than those obtained by ultrasound pachymeter, they do not have clinical significance.

Wassia A Khaja, Sandeep Grover, Amy T Kelmenson, Lee R Ferguson, Kumar Sambhav, Kakarla V Chalam Department of Ophthalmology, University of Florida, College of Medicine, Jacksonville, FL, USA Background: Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound pachymetry (US pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US pachymetry with SL-OCT, specular microscopy, and Orbscan. Method: This is a prospective, comparative study done in an institutional setting. Thirty-two eyes of 32 subjects with no known ocular disease and best-corrected visual acuity of 20/20 were enrolled. CCT measurements were obtained using SL-OCT, specular microscopy, scanning slit topography (Orbscan), and US pachymetry. Three measurements were made with each instrument by the same operator. Mean, standard deviation, and coefficient of variation were calculated for CCT measurements acquired by the four measurement devices. Bland–Altman plot was constructed to determine the agreements between the CCT measurements obtained by different equipment. Results: The mean CCT was 548.16±48.68 µm by US pachymetry. In comparison, CCT averaged 546.36±44.17 µm by SL-OCT, 557.61±49.92 µm by specular microscopy, and 551.03±48.96 µm by Orbscan for all subjects. Measurements by the various modalities were strongly correlated. Correlations (r2) of CCT, as measured by US pachymetry compared with other modalities, were: SL-OCT (r2=0.98, P

Purpose: The aim of this study was to investigate the relationship between central corneal thickness and intraocular pressure measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry. Patients and Methods: The study included 45 persons (90 eyes), divided into 4 groups: a) 10 normal volunteers (20 eyes); b) 16 patients (32 eyes) with primary open-angle glaucoma; c) 8 patients (16 eyes) with normal-tension glaucoma; and d) 11 patients (22 eyes) with ocular hypertension. Intraocular pressure was measured by Goldmann applanation tonometry and Pascal dynamic contour tonometry, and central corneal thickness was measured by ultrasound pachymetry. The relationship between intraocular pressure and central corneal thickness was evaluated. Results: Intraocular pressure was correlated positively but not strongly enough with central corneal thickness when it was measured by Goldmann applanation tonometry. On the contrary, there was no correlation between intraocular pressure and central corneal thickness when intraocular pressure was measured by Pascal dynamic contour tonometry. Conclusion: Central corneal thickness is an important variable in the evaluation of intraocular pressure by Goldmann applanation tonometry. This factor does not interfere with the intraocular pressure measurements taken by Pascal dynamic contour tonometry.

The purpose of this study is to determine the influence of post-surgical corneal edema on the reliability and reproducibility of central corneal thickness (CCT) measurements by a Scheimpflug camera (Pentacam), ultrasound pachymetry (USP), and anterior-segment spectral-domain optical coherence tomography (AS-OCT). Thirty-two patients planned for cataract surgery (n = 16) or vitrectomy (n = 6) were included in a prospective study. The non-surgery eye was used as control. Two investigators acquired two measurements each, with the Pentacam (Oculus, Germany) and the AS-OCT (Heidelberg Engineering, Germany) in a randomized order, followed by USP (Tomey SP-100, Germany). CCT was evaluated using the apex value for Pentacam, the corneal apex cut in AS–OCT and averaging eight single measurements for USP. Coefficients of variation (COV) and intra-class correlation coefficients (ICC) were determined. Post-surgery corneas showed a thickness of (investigators 1 and 2): Pentacam (615.9 ± 58.02 μm and 615.1 ± 60.17 μm), USP (601.4 ± 63.77 μm and 614.5 ± 70.91 μm), AS-OCT (608.8 ± 65.67 μm and 606.9 ± 64.41 μm) ,with no significant difference (ANOVA p > 0.99). The COVs (investigators 1 and 2) for control eyes were: Pentacam (0.78 ± 0.52 and 0.70 ± 0.76), USP (0.66 ± 0.29 and 0.98 ± 0.44), AS-OCT (0.59 ± 0.61 and 0.59 ± 0.40). The COVs (investigators 1 and 2) for post-surgical eyes were: Pentacam (0.98 ± 1.25 and 0.97 ± 0.73), USP (0.73 ± 0.64 and 1.35 ± 0.85), AS-OCT (1.34 ± 1.57 and 1.19 ± 1.18).The ICC was determined in post-surgery corneas (ICC > 0.96) and control corneas (ICC > 0.95). USP measurements have the highest user dependence. Post-surgical corneal edema leads to higher intraobserver variability. All methods reached a high level of agreement in CCT determination in edematous as well as healthy corneas.

ObjectiveTo obtain normative data for the canine cornea and conjunctiva using high-resolution time- and Fourier-domain optical coherence tomography (TD-OCT and FD-OCT) and ultrasound pachymetry (USP).AnimalsOne hundred sixty-eight eyes of 133 healthy young intact laboratory beagles.ProceduresThe cornea and conjunctiva of 16 eyes of 8 healthy young intact female beagles were imaged using FD-OCT. Corneal thickness was measured with FD-OCT and USP, while corneal epithelial thickness and conjunctival epithelial thickness were measured with FD-OCT. The central corneal thickness (CCT) was determined in 152 eyes of 125 healthy young adult intact female (35) and male (90) beagles using TD-OCT. Mixed effects linear regression was used for statistical analysis.ResultsThe CCT was (mean±standard deviation) 497.54±29.76, 555.49±17.19, and 594.81±33.02μm as measured by FD-OCT, USP, and TD-OCT, respectively. The central, superior paraxial, superior perilimbal corneal epithelial thickness and superior bulbar conjunctival epithelial thickness were 52.38±7.27, 56.96±6.47, 69.06±8.84 and 42.98±6.17μm, respectively. When comparing techniques used for measuring CCT (USP vs. FD-OCT and FD-OCT vs. TD-OCT), USP and TD-OCT generated significantly greater values in comparison with FD-OCT (both P&nbsp

Purpose.To assess the reliability and comparability of measuring central corneal thickness (CCT) and thinnest corneal thickness (TCT) using a new Scheimpflug-Placido analyzer (TMS-5, Japan) and ultrasound (US) pachymetry.Methods.Seventy-six healthy subjects were prospectively measured 3 times by 1 operator using the TMS-5, 3 additional consecutive scans were performed by a second operator, and ultrasound (US) pachymetry measurements were taken. The test-retest repeatability (TRT), coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were calculated to evaluate intraoperator repeatability and interoperator reproducibility. Agreement among the devices was assessed using Bland-Altman plots and 95% limits of agreement (LoA).Results.The intraoperators TRT and CoV were μm and 2.0%, respectively. The interoperators TRT and CoV were μm and 1.0%, respectively, and ICC was >0.90. The mean CCT and TCT measurements using the TMS-5 were 15.97 μm (95% LoA from −26.42 to −5.52 μm) and 20.32 μm (95% LoA from −30.67 to −9.97 μm) smaller, respectively, than those using US pachymetry.Conclusions.The TMS-5 shows good repeatability and reproducibility for measuring CCT and TCT in normal subjects but only moderate agreement with US pachymetry results. Caution is warranted before using these techniques interchangeably.

Ziel der Arbeit Analyse zur Genauigkeit und Reproduzierbarkeit der Augeninnendruckmessung sowie Pachymetrie mittels Corvis ST® (CST).

PurposeTo assess the repeatability, reproducibility, and agreement of central corneal thickness (CCT) measured by non-contact Fourier domain optical coherence tomography (FD-OCT; OptoVue) with the other two contact devices, ocular response analyzer (ORA; Reichert Ophthalmic Instruments) and Ultrasound Pachymetry (USP; DGH Technologies).MethodsThis observational cross-sectional study measured CCT sequentially using FD-OCT, ORA and USP. The first 16 volunteers (32 eyes) received three measurements by two independent examiners in a single session to determine intra-observer repeatability and inter-observer reproducibility. An additional 27 volunteers (54 eyes) received one measurement by the same examiner. The measurements of all 86 eyes were analyzed for the difference, correlation, and agreement among the three devices.ResultsFD-OCT measured the thinnest while USP measured the thickest CCT (548.6 ± 28.3 μm, 556.9 ± 28.8 μm, and 560.0 ± 28.8 μm by FD-OCT, ORA, and USP, respectively, p

Teberik, Kuddusi/0000-0003-3141-0531 WOS: 000451676200016 PubMed: 29022163 BackgroundTo compare the consistency between the average scores of the contact central corneal thickness measurements from ultrasound pachymetry devices still gold standard, such as iPac((R)) and Echoscan US-500, and noncontact measurements via Pentacam HR and Sirius topography.MethodsThis prospective study, subsequently admitted to the ophthalmology department, 76 healthy individuals were performed. The measurements were repeated three times for each eye, and average scores were statistically analyzed on the same day and almost at the same time. While measuring the eyes, Pentacam HR, Sirius topography, iPac((R)), and Echoscan US-500 were used, respectively. The inter-rater agreement of measurements from the devices was assessed with intraclass correlation coefficient, and 95% Confidence Interval and p values demonstrating statistically significance were also presented. In the graphical assessment of the agreement, the Bland-Altman graph was used.ResultsAmong 76 study participants, 43 (56.6%) were composed of women, and age level was 38.612.5years, ranging between 18 and 69. It was observed that the highest agreement was between the measurements obtained from Echoscan US-500 and iPac((R)) devices, but the agreement between the measurements of different devices was higher than 0.90. Bland-Altman graphics were also investigated; the results of four different devices were seen to be consistent with one another.ConclusionsTherefore, the devices we compared in the study can be used as alternatives to one another due to the higher consistency between CCT measurements provided with through UP devices of Echoscan US-500 and iPac((R)), and Pentacam HR and Sirius topography devices. p id= Par5 Clinical Trial Registration number: 2016/112

PURPOSE To evaluate and compare central corneal thickness (CCT) values measured with anterior segment optical coherence tomography (AS-OCT), noncontact specular microscopy (NCSM), and ultrasound pachymetry (USP). MATERIALS AND METHODS CCT was measured in 182 healthy eyes without ocular abnormalities other than refractive errors. Three consecutive measurements of CCT by the same examiner were obtained during the same session. The testing sequence of AS-OCT and NCSM was randomly selected. The USP always was performed after the noncontact examinations. RESULTS The average CCT measured by AS-OCT, NCSM, and USP were 535.8±35.5, 547.7±38.2, and 537.4±37.5 μm, respectively. The mean differences between modalities were 11.8±14.7 μm (P

Objective To determine the central corneal thickness (CCT) by ultrasonic pachymetry and the effect of these values on the measurements of intraocular pressures (IOP) with rebound tonometry (TonoVet®) in a captive flock of black-footed penguins (Spheniscus dermersus). Variations in CCT by age and weight, and variations in IOP by age were compared. Animal studied Both eyes of 18 clinically normal black-footed penguins (Spheniscus dermersus) were used. Procedure The IOP was measured by the TonoVet® in both eyes of all the penguins. CTT measurements were performed 5 min later in all eyes using an ultrasound pachymeter. Results The mean IOP values ± SD were 31.77 ± 3.3 mm Hg (range of mean value: 24–38). The mean CCT values were 384.08 ± 30.9 μm (range of mean value: 319–454). There was no correlation between IOP and CCT values (P = 0.125). There was no difference in CCT measurements by age (P = 0.122) or weight (P = 0.779). A correlation was observed (P = 0.032) between IOP values and age. The coefficient of correlation was negative (ρ = −0.207). Conclusions Ultrasound pachymetry has shown to be a reliable and easy technique to measure CCT in penguins. No correlation was observed between IOP and CCT values in this study. IOP showed a significant but weak decrease as age increased in the black-footed penguin.

Purpose To compare intraocular pressure (IOP) between the new non-contact tonometer Corvis ST (CST), the Goldmann applanation tonometry (GAT) and Icare Pro rebound tonometer (PRO). Methods A total of 178 eyes of 178 healthy subjects were selected for the study. Measurements of IOP were made in a random order with GAT, PRO and CST. Central corneal thickness (CCT) was determined by ultrasound pachymetry. The mean of three valid measurements of each variable was used in the statistical analysis. The relationship between the tonometers was established using Bland–Altman plots. Results Mean IOP was 15.5 ± 2.8 mmHg for GAT, 15.4 ± 2.8 mmHg for CST, and 14.6 ± 2.3 mmHg for PRO. The mean differences between pairs of tonometers were: GAT-PRO = 0.9 ± 1.7 mmHg ( p p = .398), and PRO-CST: −0.8 ± −0.7 mmHg, p r = 0.325, p r = 0.385, p r = 0.428; p Conclusions The differences found between PRO and GAT were significantly higher than those found between CST and GAT, which showed non-significant differences. The measurements of the three tonometers were affected by the CCT.

The aim of this study was to evaluate the repeatability of central corneal thickness (CCT) measurements in normal eyes using 2 new noncontact specular microscopes (NCSMs) EM-3000 (Tomey, Japan) and SP-02 (CSO, Italy) and to compare the results with those obtained from an SP-3000P NCSM (Topcon, Japan) and ultrasound pachymetry (USP).Seventy subjects were enrolled in a prospective study. A single experienced ophthalmologist performed tests with each of the 4 instruments. Measurements were obtained in the right eye during the same session. The testing sequence of the NCSM was randomly selected. After performing noncontact examinations, the USP was performed to derive the CCT measurements. Intraoperator repeatability was analyzed using within-subject coefficient of variation and intraclass correlation coefficients. The agreement between NCSMs or NCSM and USP was assessed with Bland-Altman plots and 95% limits of agreement (LoA).The mean CCT values measured by SP-3000P, EM-3000, SP-02, and USP were 513.66 ± 33.14 μm, 529.12 ± 33.22 μm, 549.06 ± 40.27 μm, and 539.01 ± 35.73 μm, respectively. All coefficients of variation were1.3%, and the intraclass correlation coefficients were0.95. There were statistically significant differences between any 2 devices as determined by CCT measurements. The mean difference between paired comparisons was9 μm. The 95% LoA ranges were broad, and the greatest 95% LoA was found to exist between SP-3000P and SP-02.The new NCSMs and USP all show a high intraoperator repeatability for CCT measurements in normal eyes. However, interdevice agreement was poor and prevented the comparison of CCT measurements taken with different instruments.

Significance of central corneal thickness has been increasing in ophthalmology practice. It is an important clinical evaluation tool especially prior to refractive surgery and in diagnosis of glaucoma and keratoconus. Refractive surgery is planned according to preoperative central corneal thickness measurements. Besides, in order to determine actual intraocular pressure, central corneal thickness is measured and corrected eye pressure is obtained. Today, devices used in measurement of central corneal thickness do the measurement according to two principles. First and relatively older method is ultrasonic method. Optic method is the second and more recent method. In daily practice, the most commonly used clinical method in measurement of central corneal thickness is ultrasound pachymeter. However, this measurement technique requires contact between cornea and probe and gives thinner measurement results compared to the methods that use optic principle. Recently, several technologic methods based on optics have been put in use; they provide advantages of non-contact technique and objective determination of central corneal thickness. Of these methods, most commonly used include Specular Microscopy, Optical coherence tomography, Laser Doppler Interferometry, Optical low coherence reflectometry pachymetry, Optic based topographic mapping (also called screening section pachymetry) and Pentacam. In this article, it was aimed to evaluate importance of central corneal thickness in clinical use and compare measurement methods. J Clin Exp Invest 2014; 5 (1): 153-158

Purpose: To compare central corneal thickness (CCT) values obtained by Lenstar (LE), Pentacam (PC), specular microscopy (SM) and ultrasound pachymetry (UP) in healthy corneas and study their influence on intraocular pressure (IOP) readings determined by Goldmann applanation tonometry (GAT). Methods: CCT was measured in 76 healthy subjects by LE, PC, SM and UP. We established Lin's concordance correlation coefficient (ρ-C) between different techniques. The influence of CCT on GAT was established through univariate linear regression models, IOP being the dependent variable. Results: The highest ρ-C was found between LE and SM at 0.94 (95% CI: 0.91-0.96) and between LE and UP at 0.95 (95% CI: 0.94-0.97). IOP readings showed less variability when CCT was determined using LE (7.7%, B = 0.16; 95% CI: 0.004-0.28). Conclusions: Although CCT values obtained with UP, PC, SM and LE show good correlation, these methods are not completely interchangeable. The amount of IOP variation differs when CCT is determined using LE or SM.

Ultrasound pachymetry (UP) is currently the most common technique used to evaluate central corneal thickness (CCT). New devices which allow assessment of CCT without corneal contact have been compared, but there are discrepancies among instruments. The aim of this study was to compare CCT measurements obtained by UP and ultrasound biomicroscopy (UBM) in 28 eyes of 14 healthy Beagles dogs. Mean CCT±standard deviation (SD) were 552±63μm for UP and 551±55μm for UBM. UBM showed both a fixed and proportional bias when compared to ultrasound pachymetry, but this was not considered to be clinically important. Measured CCT did not differ between UP and UBM (P=0.796). The intra-class correlation coefficient indicated a strong agreement between methods (0.990). The CCT measurements between left (548±61μm) and right (555±59μm) eyes did not differ (P=0.760). Male dogs had higher CCT measurements than female dogs (P=0.038).

Background To determine the difference between corrected intraocular pressure (IOP), based on the central corneal thickness (CCT), measured by the noncontact anterior segment anterior segment optical coherence tomography (AS-OCT), versus contact ultrasound pachymetry (USP) in the management of glaucoma patients. Patients and methods Ophthalmology Department, Ain Shams University, Cairo, Egypt. The study is a prospective, nonrandomized case series. Fifty patients were diagnosed with open-angle glaucoma and controlled with medical treatment with prostaglandin analogs and β-blockers fixed combination, controlled under medical treatment. CCT is measured by two methods, the AS-OCT and by the USP of ocular response analyzer. IOP was measured by applanation tonometry. Corrected IOP was calculated adjustment factor using Ehler’s correction nomogram, statistical analysis of the adjusted IOP with the contact and noncontact methods was done in relation to the CCT measurements. Results The mean age was 60.5±5.24 years, 54% of the studied patients were men while 46% were women. The mean CCT using AS-OCT for the right eye was 529.86±43.52 μm and for the left eye was 530.28±43.57 μm, while CCT using USP for the right eye was 534.88±43.59 μm and for the left eye was 533.34±44.33 μm. Highly significant correlation between CCT was measured by AS-OCT and ultrasound; 0.94 (P

To compare central corneal thickness (CCT) measurements with a rotating Scheimpflug camera (RSC), noncontact specular microscopy (SM), optical low-coherence reflectometry (OLCR), and ultrasonic pachymetry (UP) in keratoconus (KC) patients.In this prospective study, four CCT measurements taken with an RSC, SM, OLCR, and UP were compared in 81 eyes of 44 consecutive KC patients. The KC patients were divided into four subgroups according to Amsler-Krumeich's KC classification.The RSC and UP measurements of the CCT were not statistically significant in all the groups. Comparison of the SM vs. the OLCR measurements yielded statistically significant differences in all the KC patients and in all KC stages. In all the KC patients, RSC and OLCR showed a high correlation coefficient factor (r = 0.87, p = 0.000).CCT measurements with RSC are comparable to those achieved with UP. Compared with the other devices, according to SM measurements, the central cornea is thicker in all keratoconic eyes and in all KC grades, and it is thinner according to OLCR. RSC, UP, SM, and OLCR should not be used interchangeably in keratoconic eyes.

Purpose To evaluate repeatability within and between examiners and to assess agreement in corneal thickness measurements obtained by anterior segment optical coherence tomography (ASOCT) and ultrasonic pachymetry (USP). Methods This was a prospective, observational study. Fifty-one patients who visited a glaucoma service with suspected glaucoma, glaucoma, or cataract were enrolled. Patients with a history of corneal surgery or abnormalities and those who were uncooperative for examinations were excluded. Each patient underwent ASOCT followed by USP, with each test performed by two different examiners. Measurement repeatability was evaluated using intraclass correlation coefficient (ICC) values. Agreement in corneal thickness measurements was evaluated by the Bland and Altman plot method. Linear regression analysis was used to assess the relationship between ASOCT and USP measurements. Results USP and ASOCT corneal thickness measurements revealed high intraexaminer and interexaminer repeatability (ICCs ≥ 0.978). ASOCT corneal thickness measurements of a central 2-mm zone showed higher intraexaminer (ICC = 0.999) and interexaminer (ICC = 0.999) repeatability than USP measurements or ASOCT measurements of the vertex. The 95% limit of agreement (LoA) between the vertex-centered ASOCT and the USP scan was between 3.68 and 24.76 μm. The 95% LoA between the central 2-mm zone ASOCT and the USP scan was between 3.75 and 23.39 μm. Average ASOCT corneal thickness was less than USP measurements, but ASOCT thickness could be converted to USP thickness through linear regression equations. Conclusion Both devices have good intraexaminer and interexaminer repeatability, though ASOCT has slightly better interexaminer repeatability. ASOCT accurately and reliably measures corneal thickness in a noninvasive manner.

To compare the effect of nonpreserved oxybuprocaine and preserved artificial tears on central corneal thickness (CCT) obtained by 2 pachymeters.In this prospective, placebo-controlled study, involving a random sample of 100 eyes of 50 subjects, aged 24±2.3 years, CCT readings were obtained in 2 separate sessions with the Topcon SP-3000P and ultrasound pachymetry (USP), respectively, before, 5 and 10 min after instillation of a drop each of either oxybuprocaine hydrochloride (oxybuprocaine HCl) (group 1) or carboxymethylcellulose sodium, thera tears (group 2), and placebo.The baseline mean CCT for SP-3000P was 509±38 μm and 542±36 μm for USP. No statistical significant differences between baseline CCTs (P0.05 for both devices) in both groups. In both group experimental eyes, neither SP-3000P nor USP-measured CCTs varied significantly from the control eyes at 5 (P0.05) and 10 (P0.05) mins postinstillation of drops in both sessions. In group one, the 95% confidence intervals (CIs) for the SP-3000P CCTs were similar at 5 (-16 to 17 μm) and 10 min (-16 to 17 μm), but in the USP-measured CCTs, it was wider at 10 min (-41 to 46 μm) than at 5 min (-30 to 41 μm) postinstillation. In group two, the 95% CIs at 5 and 10 mins postinstillation, respectively, ranged between -20 and 47 μm, -21 and 43 μm (SP-3000P) and -29 and 23 μm, -26 and 23 μm (USP). Within groups and between groups, variations in CCT were similar at both times intervals in all comparisons.Although oxybuprocaine HCl and thera tears consistently did not affect the mean CCT obtained by both devices at both time intervals, variation in SP-3000P measured CCT was more consistent in both sessions and narrower in relation to USP-measured CCT. It may be reasonable to suggest that measurements of CCT in normal patients be taken before examinations requiring instillation of anesthetics or such measurements when obtained postinstillation of either oxybuprocaine or preserved artificial tears be interpreted with caution.

To compare the effect of tetracaine 1% on central corneal thickness (CCT) measurements obtained by the ultrasound pachymetry (USP) and Topcon SP-3000P specular microscope.In the following sequence, SP-3000P before anesthesia, USP before anesthesia, SP-3000P 10 mins after anesthesia, USP 10 mins after anesthesia, CCT measurements were obtained from 100 randomly selected eyes of 50 oculo-visually young adults in 2 measurement sessions.The CCT before instilling anesthetic did not vary significantly in each technique within session (P0.05) and between sessions (P0.05). Baseline CCT measurements obtained by the USP were significantly (P0.0001) higher than that of SP-3000P by about 28 μm and 29 μm in sessions 1 and 2, respectively. A small but statistically insignificant increase in CCT (P0.05) was observed 10 mins after instilling one drop of 1% tetracaine in both sessions of SP-3000P, whereas a statistically significant increase (P0.05) in CCT in both sessions of USP was observed. The precision of the effects of anesthesia in the USP for sessions 1 and 2 was±15 μm and±31 μm, and in SP-3000P sessions 1 and 2, respectively, was±16 μm and±13 μm.Topical anesthetic might have an effect on CCT measurements made with the ultrasound pachymeter. Such an effect could be due to instability of the tear film caused by the anesthetic, and this effect was not measurable with the SP-3000P suggesting that the difference in the principles of operation of both pachymetry devices might play a significant role in the detection of changes in CCT induced by topical anesthetic and the difference in CCT measurements observed between techniques.

Aim: To study the correlation between central corneal thickness (CCT) measured by ultrasound pachymetry and Frequency Doubling Technology Perimetry (FDT) in patients aged more than or equal to 40 years with high IOP and normal discs. Materials and Methods: This research work has two arms, the rural arm is an eye care centre in Hooghly District of West Bengal (Village: Kuliapara, P.O. Dhobapara, P.S. Balagarh)and the urban arm is a tertiary eye hospital in Kolkata, West Bengal. People aged 40 years and above or those turning 40 in the calendar year with high IOP and normal discs and not on any topical or systemic medications underwent complete ophthalmological examination including CCT assessment by ultrasound pachymetry (Ocuscan RxP) and FDT (Humphrey, Carl Zeiss) . Patients with history of intraocular surgery, ocular trauma, corneal opacities preventing accurate applanation tonometry and media haze dense enough to preclude adequate fundal view were not enumerated. Results: One hundred and eighty subjects fulfilled the laid down study inclusion criteria. Average CCT for the right eye(RE) is 530.74 µ and that for the left eye(LE) is 531.32µ(p=0.61, not statistically significant). IOP in the RE varied from 18 to 32 mm Hg with an average value of 23 mm Hg and that in the LE varied from 14 to 32 mm Hg with an average value of 22 mm Hg. Abnormal FDT in either eye was present in eighteen subjects of whom nine subjects had bilateral abnormal FDT and eight subjects had only RE affection and one subject had only LE affection. Conclusion: Our study concludes that the included subjects with abnormal FDT had thinner CCTs as compared to those with a normal FDT. Extending this relation further, we conclude that among subjects with a higher IOP and normal discs or patients grouped as ocular hypertensives, thicker corneas lower the risk for development of early glaucomatous functional damage as picked up by FDT, as compared to patients with thinner corneas.

Objetivo: Determinar la relación entre el tonómetro de contorno dinámico (TCD), Goldmann (TG) y neumotonómetro (NT) en pacientes con hipertensión ocular (HTO) y su relación con el grosor central de la córnea (GCC) y amplitud del pulso ocular (APO). Método: Se han incluido 60 pacientes (101 ojos) con presión intraocular (PIO)>21mmHg con TG y sin alteraciones glaucomatosas en disco óptico y campo visual. Se ha medido la PIO con TG, TCD y NT, la APO con el TCD y el GCC con paquímetro de ultrasonido. Se ha estudiado la diferencia de PIO entre los tres tonómetros mediante el test no paramétrico de Wilconxon y la relación de la APO con el GCC y la PIO con el coeficiente de correlación de Spearman. Resultados: La mediana de PIO con NT fue de 24mmHg (RIC: 22-26), con TG de 22mmHg (RIC: 22-24)y con TCD de 28,2mmHg (rango intercunatílico [RIC]:24,1-30,7). En comparación con el TG la PIO fue mayor con el NT y con el TCD, siendo la diferencia de medianas de 2,0 y de 6,2mmHg respectivamente. La media del GCC fue de 594,5μm (DE 30,0), encontrándose una asociación estadísticamente significativa entre esta y la PIO con TG (r:0,209; p=0,036) y de magnitud similar aunque sin ser significativa con el TCD (r:0,195; p=0,051). No se encuentra asociación entre GCC y NT (r:0,15; p=0,12). La APO fue de 4,8mmHg (RIC: 3,6-6,1), incrementándose significativamente con la PIO tomada por el TG (r:0,388; p21mmHg using GAT and normal appearing optic nerve heads and normal visual fields were included. The following tests were performed simultaneously during a single visit: IOP using DCT, GAT and PNT, OPA using DCT and CCT using ultrasound pachymetry. We studied the difference IOP between these 3 tonometers using Wilcoxon non-parametric test and the effect of CCT on IOP and OPA, as well as the relationship between OPA and IOP using Spearman correlation coefficient. Results: The median PNT IOP was 24mmHg (Inter-quartile range [IQR]: 22-26), median GAT IOP was 22mmHg (IQR: 22-24), and median DCT IOP was 28.2mmHg (IQR: 24.1-30.7). PNT and DCT had higher IOP values than GAT (median 2mmHg and 6.2mmHg, respectively). Mean CCT was 594.5μm (SD 30.0). GAT IOP and DCT IOP showed an increase with increased corneal thickness (r:0.209; P=.036 and r:0.195; P=.051, respectively). PNT IOP did not change with CCT (r:0.15; P=.12). The median OPA was 4.8mmHg (IQR: 3.6-6.1), and significantly increased with GAT IOP (r:0,38; P

Purpose To evaluate the clinical usefulness of anterior segment (AS) optical coherence tomography (OCT) in diagnosis and follow-up of children with congenital corneal opacities. Design Noncomparative case series. Participants Seven consecutive patients with bilateral congenital corneal opacity between 2 days and 2.5 years of age. Methods In addition to basic outpatient examination, eyes were imaged using AS OCT. Anterior segment structures and corneal thicknesses were evaluated from the images. Three children also underwent evaluation under anesthesia, including measurement of corneal thickness with ultrasound pachymetry. Main Outcome Measures Evaluation of the type and severity of the congenital corneal opacity based on the findings in AS OCT. Results Thirteen of the 14 eyes could be imaged using AS OCT. The youngest patient studied was only 2 days old. Three distinct phenotypes were found based on the AS OCT findings. Three patients with iridocorneal adhesions were deduced to have type 1 Peters' anomaly, and 2 patients with lenticulocorneal adhesions were deduced to have type 2 Peters' anomaly. The 2 youngest patients had complete corneal opacity with features of corneal staphyloma and marked changes in the AS structures during the first months of life. Conclusions Anterior segment OCT was a valuable method in the diagnosis and follow-up of patients with congenital corneal opacities. As a fast and noncontact technique, it was applicable even for neonates. It allowed early characterization of the type and the extent of the AS disorder. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

PURPOSE To compare the accuracy of optical low-coherence reflectometry (Lenstar LS 900; Haag Streit, Koniz, Switzerland) and conventional ultrasound pachymetry (UP) (US 4000; Nidek, Japan) for measuring central corneal thickness and to assess the interexaminer reproducibilities of both devices. METHODS Department of Ophthalmology, Selcuklu Faculty of Medicine, Selcuk University was the study setting. Central corneal thickness (CCT) was measured in both eyes of 65 emmetropic patients by the same examiner using Lenstar LS 900 noncontact biometry and UP. To assess the interexaminer reproducibility, 2 different examiners consecutively obtained CCT measurements in 16 eyes with Lenstar LS 900 noncontact biometry and UP. RESULTS Mean CCT measurements with Lenstar LS 900 noncontact biometry and ultrasound biometry were 541.09 ± 33.8 and 545.69 ± 34.0, respectively. Significant correlation was present between these 2 measurements; intraclass correlation coefficient was found to be 95.8% (95% confidence interval: 93.2%-97.4%)(P < 0.001). Interexaminer reproducibility with Lenstar was high, and the intraclass correlation was found to be 99.3% (95% confidence interval: 98.0%-99.7%). We have also investigated the interexaminer reproducibility with UP in these 16 patients, and the results showed a 99.2% (95% confidence interval: 97.7%-99.7%) intraclass correlation. CONCLUSIONS The results of Lenstar LS 900 noncontact biometry correlated with the results of UP. It may be used as an alternative method to UP for measuring CCT. Because of the mild underestimation of CCT by Lenstar, the measurements should be carefully evaluated in patients whose intraocular pressure must strictly be monitored.

Purpose We compared the SLc Original (SLc) and One-Use Plus (OUP) microkeratomes for ultrathin Descemet's stripping automated endothelial keratoplasty (DSAEK) lamella preparation and storage, vis-a-vis accuracy, endothelial cell loss (ECL) and lamellar surface roughness (LSR). Methods Twenty-five human corneas were dissected with single-use heads of different sizes aiming for a posterior lamella (PL) thickness of 85 μm, after which they were incubated for 6 days in a 5% dextran medium. Before preparation (0 hr) and 1, 24, and 144 hr after dissection, ECL and corneal thickness (CCT) were measured by ultrasound pachymetry (USP) and optical coherence tomography (OCT). Lamellar surface roughness (LSR) was assessed by scanning electron microscopy (SEM) and evaluated by two masked observers. Results Prior to cutting, CCTs did not differ between OCT and USP measurements, with a high correlation between the two modalities (r2 = 0.8; p

Purpose. To evaluate corneal thickness changes during pulsed accelerated corneal cross-linking (CXL) for keratoconus using a new isotonic riboflavin formula.Methods. In this prospective, interventional, clinical study patients with grades 1-2 keratoconus (Amsler-Krumeich classification) underwent pulsed accelerated (30 mW/cm2) CXL after application of an isotonic riboflavin solution (0.1%) with HPMC for 10 minutes. Central corneal thickness (CCT) measurements were taken using ultrasound pachymetry before and after epithelial removal, after riboflavin soaking, and immediately after completion of UVA treatment.Results. Twenty eyes of 11 patients (4 males, 7 females) were enrolled. Mean patient age was26±3(range from 18 to 30 years). No intraoperative or postoperative complications were observed in any of the patients. Mean CCT was507±35 μm (range: 559–459 μm) before and475±40 μm (range: 535–420 μm) after epithelial removal (P<0.001). After 10 minutes of riboflavin instillation, there was a statistically significant decrease of CCT by 6.2% from475±40 μm (range: 535–420 μm) to446±31 μm (range: 508–400) (P<0.005). There was no other statistically significant change of CCT during UVA irradiation.Conclusions. A significant decrease of corneal thickness was demonstrated during the isotonic riboflavin with HPMC application while there was no significant change during the pulsed accelerated UVA irradiation.

Purpose We sought to compare the intraocular pressure (IOP) measured by RKT-7700 and CT-80 noncontact tonometers (NCTs) with that measured by Goldmann applanation tonometry (GAT). We also examined the influence of central corneal thickness (CCT) on the agreement between both NCTs and GAT in a sub-population of healthy, young normals. Methods Triplicate IOP and CCT measurements were obtained twice from one randomized eye of 49 subjects (28 males and 21 females) aged 22.2 ± 1.3 (mean ± S.D.) years. Goldmann tonometry was performed subsequent to assessment with the RKT-7700 and CT-80, to negate the ‘ocular massage effect’, followed by ultrasound pachymetry. The results from each method were compared and assessed for repeatability and between-observer reproducibility. Analysis was performed to determine the correlation between the differences in IOP measurements and corneal thicknesses. Results The mean differences (±S.D.) in sessions 1 and 2 respectively between RKT-7700 and GAT (2.6 ± 2.0 and 2.7 ± 1.4 mmHg), between CT-80 and GAT (2.8 ± 2.0 and 3.2 ± 1.3 mmHg) were statistically significant (p

Purpose: To assess accuracy and repeatability of central corneal thickness (CCT) measurements obtained by swept-source anterior segment optical coherence tomography (AS-OCT), spectral-domain retinal OCT with corneal module and ultrasound pachymetry (USP), and to assess repeatability of pachymetric mapping with AS-OCT. Methods: 50 healthy volunteers were recruited. A single, experienced operator analysed the right eye of each participant twice in the same session with AS-OCT (‘corneal map’ routine), retinal OCT and USP. CCT measurements were compared using repeated-measures analysis of variance, Bonferroni test, Pearson correlation and Bland-Altman plots. Repeatability of thickness maps and CCT measurements were assessed using Alpha of Cronbach, intraclass correlation coefficient (ICC) and coefficient of repeatability. Results: Mean CCT ± SD was 540 ± 28.9 μm for AS-OCT, 544 ± 29.5 μm for retinal OCT and 549.3 ± 31.7 μm for USP; the differences were statistically significant (p

Resume Objectif Determiner la capacite de l’epaisseur de la cornee centrale mesuree par pachymetrie ultrasonore ou par Pentacam (l’epaisseur dans l’axe pupillaire et l’epaisseur minimum corneenne) pour differencier les temoins sains et les patients avec glaucome primaire a angle ouvert. Patients et methodes Les mesures ont ete determinees dans les yeux gauches de 123 temoins et de 128 patients glaucomateux. Les differences entre les ensembles de donnees pour chaque variable ont ete identifiees en utilisant un test t pour deux echantillons independants. Trois modeles de regression logistique binaire univariee (pour discriminer glaucome et temoins sains) ont ete construits, ou les variables predictives ont ete les determinations d’epaisseur corneenne. Resultats La distribution des variables etait normale. Les groupes des temoins et des patients n’ont pas differe de maniere significative en termes de pachymetrie ultrasonore, mais different dans l’epaisseur dans l’axe pupillaire (difference moyenne 22,01 μm en faveur des temoins 95 % IC : 5,61–34,15) et de l’epaisseur minimum corneenne (difference moyenne 21,65 μm en faveur des temoins 95 % IC : 3,05–32,25). Le modele de regression logistique pour la pachymetrie ultrasonore n’a pas ete significatif (p = 0,051), mais une capacite de discrimination significative a ete montree par l’epaisseur dans l’axe pupillaire (expB = 0,987 ; 95 % IC : 0,99–0,993 ; sensibilite : 58,5 % ; specificite : 64,8 %) et l’epaisseur minimum corneenne (expB = 0,987 ; 95 % IC : 0,981–0,994 ; sensibilite : 61,9 % ; specificite 63,1 %). Conclusions Les mesures de l’epaisseur de la cornee centrale determinees en utilisant le Pentacam ont montre une capacite non negligeable de differencier entre temoins et patients glaucomateux, sans etre un test diagnostic ad hoc.

Purpose We present an evaluation of corneal pachymetry measurements by Galilei dual Scheimpflug camera by comparing central corneal thickness measured by Galilei with Orbscan II and ultrasonic pachymetry. Setting Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences and Negah Eye Center, Tehran, Iran. Materials and methods Central corneal thickness (CCT) was measured in 184 eyes of 92 healthy subjects using Galilei, Orbscan II, and ultrasonic (US) pachymetry. Considered as a benchmark, the measurements by US pachymetry were compared with those measured by the other 2 systems. Results Mean CCT was 544.4 ± 33.4 µm, 546.7 ± 37.9 µm, and 555.8 ± 29.6 µm as measured by US pachymetry, Orbscan II, and Galilei systems, respectively. The mean difference of readings measured by US pachymetry with those measured by Orbscan II (acoustic coefficient 0.96) and Galilei were 2.3 µm and 10.2 µm, respectively. In spite of this discrepancy, the Galilei system had better agreement with US pachymetry than Orbscan II and US pachymetry (correlation coefficient 0.947 vs 0.817) and considering 0.98 as acoustic coefficient for Galilei CCT reading, makes its measurements identical to ultrasound pachymetry. Conclusions Galilei measurements of CCT are well correlated with ultrasound pachymetry in normal eyes. After considering an acoustic coefficient equal to 0.98 for Galilei, its measurements will become equal to ultrasound values.

Purpose To evaluate the modulatory effect of various riboflavin 0.1% and 0.2% compositions on the central corneal thickness (CCT) in fresh porcine corneas. Setting Department of Ophthalmology, Johannes Gutenberg University of Mainz, Mainz, Germany. Design Experimental study. Methods The CCT in freshly enucleated porcine globes was measured by ultrasound pachymetry before and after (if applicable) deepithelialization and every 10 minutes thereafter during 120 minutes of eyedrop application. In Groups 1 and 2 (controls), no eyedrops were applied. In Groups 3 and 4, isotonic riboflavin eyedrops were used. In Groups 5 to 9, hypotonic riboflavin eyedrops were given. In Groups 10 and 11, preparations for transepithelial crosslinking were applied. In Groups 2 to 9, deepithelialization was performed. The final CCT in the groups was compared by analysis of variance. Results One hundred ten freshly enucleated porcine globes were used. The mean final CCT compared with preoperative values was 97% ± 4% (SD) in Group 1, 91% ± 4% in Group 2, 66% ± 5% in Group 3, 151% ± 13% in Group 4, 65% ± 2% in Group 5, 105% ± 3% in Group 6, 120% ± 4% in Group 7, 130% ± 4% in Group 8, 132% ± 4% in Group 9, 114% ± 2% in Group 10, and 114% ± 4% in Group 11. The differences between Group 1 and each of Groups 3, 4, 5, 7, 8, and 9 were statistically significant (P Conclusion There was considerable variation in the final CCT as a result of varying riboflavin eyedrop compositions. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

To evaluate optical coherence tomography (OCT) in the measurement of donor corneas in preparation for endothelial keratoplasty.Donor corneas were imaged by OCT while immersed in preservation medium. Central corneal thickness (CCT) was measured by OCT from the Bowman layer to the endothelium. The corneas were then mounted on an artificial anterior chamber, and the epithelium was removed. Ultrasound pachymetry (USP) was used to measure CCT just before sectioning with a microkeratome. The central graft thickness (CGT) was measured by USP. The graft was then returned to the medium and imaged by OCT.The study included 154 donor corneas. The average CCT measured by OCT (550 ± 63 μm) was thicker (P0.001) than that measured by USP (507 ± 54 μm). Similarly, the CGT measured by OCT (158 ± 41 μm) was thicker (P = 0.0005) than that measured by USP (153 ± 38 μm). The predictability of cut depth, as assessed by pooled standard deviation (SD), was better (P = 0.023) for USP (41 μm) compared with OCT (48 μm). The graft was thicker (P0.001) peripherally than centrally in OCT images. The predictability of cut depth by OCT was better (P0.001) for corneas thinner than 600 μm (SD = 45.6 μm) compared with those thicker than 600 μm (SD = 86.9 μm).The donor corneal measurements by OCT were not as predictable as those by USP. The predictability of graft thickness, however, could be optimized using OCT to select for corneas thinner than 600 μm and then using immediate precut USP to set the microkeratome depth. A graft thickness profile measured by OCT could be useful to the surgeon.

To assess central corneal thickness (CCT) and corneal haze in keratoconus eyes following corneal cross-linking (CXL).Prospective noncomparative case series.Forty patients (44 eyes) with keratoconus that had serial evaluation for CCT, following CXL, using high-definition optical coherence tomography (HD-OCT), ultrasound pachymetry (USP), and dual Scheimpflug tomography. CCT was measured at baseline, then at 2 weeks and 1, 3, 6, and 12 months postoperatively.The mean baseline CCT measurements were 470.02 μm, 469.79 μm, and 466.66 μm using the HD-OCT, the USP, and dual Scheimpflug tomography, respectively (P = .91). Following CXL, the mean CCT measurements by dual Scheimpflug, at all follow-up periods, were lower compared to mean baseline reading (P.003). The mean CCT measurements by the HD-OCT and USP were similar to baseline readings except for the thicker readings at the 2-week follow-up visit. Overall, the mean CCT obtained by the USP was similar to that obtained by the HD-OCT throughout the 12-month period. However, the mean CCT measurements obtained by dual Scheimpflug tomography were statistically and clinically significantly lower than those obtained by both HD-OCT and USP at all follow-up visits.USP and HD-OCT showed better agreement in CCT readings at all visits, and may better estimate the true CCT following CXL as compared to dual Scheimpflug tomography. The lower mean CCT post-CXL as measured by the latter seems to be correlated with the amount of haze that develops after cross-linking.

The aim of this study is to report surgical outcomes in patients undergoing phacoemulsification surgery (PE) with versus without ophthalmic viscosurgical devices (OVDs). This is a comparative case series study. In total, 145 patients who performed PE with OVDs in 68 eyes (Group 1) and without OVD in 77 eyes (Group 2) were enrolled. A comprehensive ophthalmological examination was performed including slit-lamp, fundus examination. Best-corrected visual acuity (BCVA), intraocular pressure (IOP) specular endothelial microscopy (SM), and ultrasound pachymetry (UP) were also measured before surgery and at four-time points postoperatively. The differences in baseline characteristics as well as in outcomes were compared between the two groups. The mean BCVA was 0.41 ± 0.26 logMAR in Group 1 and 0.54 ± 0.34 in Group 2 at postoperative first day, with a significant difference (p

To compare specular microscopy (Topcon SP-3000P, Topcon Corporation, Tokyo, Japan) and ultrasound (US) technology when evaluating central corneal thickness (CCT) prior to and after phacoemulsification. Corneal edema was assessed in phacoemulsification patients due to senile cataract by measuring CCT preoperatively and 1 day, 1 month, and 3 months postoperatively. Bland–Altman analysis was performed to assess interchangeability between pachymetry techniques for each visit. Repeated measures analysis of variance was performed to evaluate variation in CCT agreement depending on the degree of corneal edema. One hundred and eighteen patients aged 73.9 ± 10.1 years were recruited. Topcon SP-3000P provided significant (p

To assess flap-thickness predictability with a pendular microkeratome (130 μm head).Eye Institute of Thrace, Democritus University of Thrace, Alexandroupolis, Greece.Clinical trials.The study comprised 263 eyes (132 patients). Laser in situ keratomileusis was performed using the 130 μm head of the Carriazo pendular microkeratome; right eyes were treated first. Ultrasound pachymetry and topography were used for central corneal thickness (CCT) and keratometry (K) measurements. Evaluation included flap thickness, flap diameter, and flap shape.The mean flap thickness was 125 μm ± 22 (SD) (range 74 to 187 μm) in right eyes and 112 ± 21 μm (range 61 to 190 μm) in left eyes. Flap thickness was significantly correlated with preoperative CCT (r = 0.271; P.001) but not with K values or the manifest refraction spherical equivalent (P.15). Right eyes had thicker flaps than left eyes (P.001); both were significantly below the 130 μm head thickness (mean flap thickness 119.2 ± 22.8 μm; P.001). The mean achieved flap diameter was 9.2 mm using the 9.0 ring and 9.8 mm using the 10.0 mm ring. Flap-thickness stabilization and convergence between right eyes and left eyes occurred after 100 consecutive flap cuts.Flap-thickness predictability was influenced by preoperative CCT only. All cuts were significantly thinner than the head thickness regardless of the suction ring size. Second surgical eyes had thinner flaps, possibly from blade deterioration from the first cut. Approximately 100 flaps were required as a learning curve.

PURPOSE To determine the correlation between the intraoperative donor lenticule thickness in Descemet stripping automated endothelial keratoplasty (DSAEK) and both the best-corrected visual acuity (BCVA) and endothelial cell density (ECD) at 6 months. To describe relevant surgical considerations with regard to the choice of microkeratome head. DESIGN Prospective case series. METHODS Thirty-five patients (37 eyes) undergoing DSAEK were included in this prospective case series. Intraoperative donor lenticule thickness, assessed by ultrasound pachymetry, was compared with BCVA and ECD 6 months postoperatively. RESULTS Mean BCVA logarithm of the minimal angle of resolution (logMAR) was 0.58 preoperatively and 0.29 6 months postoperatively. Three eyes were excluded from BCVA analysis. The average donor lamellae thickness was 175 μm. Mean ECD loss was 39% 6 months postoperatively compared with that preoperatively. There was no correlation between donor lamella pachymetry and BCVA logMAR and ECD at 6 months in this series (P = 0.13 and P = 0.09, respectively). Analogous to our findings, a review of published reports on donor pachymetry in DSAEK did not provide data to suggest a correlation between donor corneal thickness and postoperative BCVA or ECD. CONCLUSIONS Donor lenticule thickness does not have a direct effect on 6-month postoperative visual acuity or endothelial cells. Efforts should be made to reduce surgical trauma to the lenticule rather than adhering to a strict depth when cutting the graft. We propose using the Moria 350 μm microkeratome head for corneal thickness more than 600 μm and the 300 footplate for corneal thickness less than 600 μm.

To obtain the central corneal thickness (CCT) of healthy eyes using the rotating Scheimpflug imaging system and compare these results with conventional ultrasound pachymetry values. Interoperator reliability and repeatability of the different techniques were also determined.CCT was measured on the right eye of 46 healthy subjects with the Pentacam HR (Pentacam High Resolution; Oculus, Wetzlar, Germany) and contact ultrasound pachymetry (AL-2000; Tomey, Tennenlohe, Germany) by 2 independent investigators.Both observers obtained significantly higher CCT readings with the Pentacam HR imaging system (572 ± 33 and 575 ± 31 μm) than with the ultrasound device (546 ± 27 and 548 ± 28 μm) (P0.0001, paired Student t test). Strong and significant correlation was found between the 2 pachymetry techniques regardless of the investigator (r = 0.845 and 0.831, Spearman correlation coefficient) (P0.0001). For the Pentacam HR values, statistically significant difference was detected between the observers (P = 0.033). For both pachymetry methods, the degree of agreement between the investigators was reflected by the high interoperator intraclass correlation coefficient value (ICC = 0.96). No significant difference was disclosed between the 3 consecutive readings of either instrument (P0.05, analysis of variance).Significant difference in CCT values between the high-resolution Pentacam imaging system and the ultrasound pachymeter suggests that the 2 techniques cannot be used interchangeably in clinical practice.

Aim The aim of this study was to evaluate measurements of the central corneal thickness using OLCR and ultrasound pachymetry (IOPac). Materials and methods In a retrospective observational study, fifty patients were assessed. Central corneal thickness was measured using OLCR and ultrasound. Results The IOPac system shows results for the central corneal thickness between 419 µm and 613 µm. The OLCR values ranged between 421 and 598 µm. The coefficient of variation was 1.12 % in the case of the IOPac and 0.97 % in the case of the OLCR. The paired Student's t-test showed no significant differences between the two methods. The agreement between the two methods was high with r = 0.929. Conclusions The agreement between the results for the central corneal thickness using OLCR and ultrasound is high. The OLCR is a non-touch technology that does not require local anaesthesia, thus further reducing the risk of infection or mechanical trauma. Especially in surgical applications or glaucoma assessments, movement artefacts need to be ruled out, which potentially could cause wrong values and thus lead to wrong decisions.

This study evaluates aqueous humor dynamics in rhesus monkeys from the University of Florida inbred colony with ocular normotension and naturally occurring ocular hypertension. Eight monkeys with untreated intraocular pressures (IOPs) of less than 18 mmHg in one eye (ONT group) and seven with untreated IOPs of greater than or equal to 18 mmHg in one eye (OHT group) were included in the study. Assessments included central cornea thickness by ultrasound pachymetry, IOP by tonometry, aqueous flow and outflow facility by fluorophotometry, and uveoscleral outflow by mathematical calculation. Animals were sedated with ketamine for all measurements. Values from the two eyes of each animal were averaged, with the exception of one animal that had only one good eye. Comparisons between groups were made by Student's two-tailed unpaired t-tests. Compared to the ONT group, the OHT group had higher IOPs at all times measured (4:00 PM the day before the study, 21.2 ± 6.5 versus 14.4 ± 1.5 mmHg, p = 0.01; 9:00 AM the day of the study, 20.7 ± 6.6 versus 14.8 ± 1.2 mmHg, p = 0.03; 11:00 AM the day of the study, 16.0 ± 1.6 versus 13.3 ± 2.9 mmHg, p = 0.05) and lower aqueous flow (2.12 ± 0.40 versus 4.54 ± 1.11 μl/min, p = 0.0001), outflow facility (0.17 ± 0.10 versus 0.33 ± 0.07 μl/min/mmHg, p = 0.01) and uveoscleral outflow (p < 0.05). The elevated IOP in inbred Florida rhesus monkeys is a result of significantly reduced outflow facility and uveoscleral outflow. These animals also have slower aqueous flow than the ONT animals which does not contribute to the higher IOP.

Purpose: To compare the repeatability and reproducibility of central corneal thickness (CCT) measurements by high-resolution (HR) rotating Scheimpflug imaging and Fourier-domain optical coherence tomography (FD-OCT). CCT measurements were compared to those determined by ultrasound pachymetry (UP). Methods: In 35 healthy eyes, intra-observer repeatability for HR Scheimpflug (Pentacam) and FD-OCT (RTVue) systems was determined in consecutive images taken by an observer in the shortest time possible. Imaging was repeated again by a second observer to evaluate inter-observer reproducibility. The CCT measurements were compared among Scheimpflug, FD-OCT and UP images. Results: Mean coefficients of repeatability were 0.48% for Scheimpflug and 0.26% for FD-OCT. For Scheimpflug, the coefficient of inter-operator reproducibility was 0.87%. For FD-OCT, the coefficient of inter-operator reproducibility was 0.45%. The CCT measurements by Scheimpflug, OCT and UP images were (mean ± standard deviation) 521.7 ± 27.6 μm, 510.8 ± 28.6 μm and 516.5 ± 27.6 μm, respectively. The differences between instruments were statistically significant. The 95% limits of agreement in CCT were −0.7 to 22.5 μm for Pentacam-OCT, −13.4 to 24.0 μm for Pentacam-UP and −26.7 to 15.4 μm for OCT-UP. There was a high degree of correlation between CCT measured by all 3 methods. Conclusion: Noncontact measurements of CCT with HR Scheimpflug and FD-OCT systems yielded excellent repeatability and reproducibility and can be used interchangeably. Although both devices were comparable with UP; in clinical practice, the measurements acquired by optical modalities are not directly interchangeable with UP measurements.