Interobserver Reliability and Sensitivity to Change of a Composite Ocular Inflammatory Activity Index: UVEDAI©.

INTRODUCTION: This was a multicenter, prospective, longitudinal, observational study involving eight Spanish tertiary hospitals to determine the interobserver reliability of an uveitis disease activity index, (UVEDAI) and assess its sensitivity to change in patients with receiving pharmacologic treatment. METHODS: Patients aged ≥ 18 years diagnosed with active noninfectious uveitis were included. A complete baseline assessment was performed by two ophthalmologists who determined ocular inflammatory activity using the UVEDAI index independently of each other. The principal ophthalmologist made a new visit at 4 weeks to determine the change in inflammatory activity. The interobserver reliability analysis was performed by calculating the intraclass correlation coefficient (ICC), with the values of the variables and the UVEDAI obtained by both ophthalmologists in the more active eye at the baseline visit. Sensitivity to change in the UVEDAI index was assessed at 4 weeks from the start of pharmacologic treatment by determining the clinically relevant change, defined as a change in UVEDAI of ≥ 0.8 points over baseline. The mean change between both measures was compared using the repeated-measures t-test. RESULTS: A total of 111 patients were included. In the interobserver reliability analysis, the ICC for the UVEDAI value was 0.9, and, when compared with the mean UVEDAI values obtained by the ophthalmologists, no statistically significant differences were found (p value > 0.05). As for the sensitivity to change in UVEDAI, statistically significant differences (p value = 0.00) were found for the mean values of the index compared with baseline. In all cases, the index value decreased by > 1 point at the 4-week visit. CONCLUSIONS: The interobserver reliability of the UVEDAI was high in the total sample. Furthermore, the index was sensitive in determining the change in inflammatory activity after treatment. We believe that UVEDAI is a disease activity index that enables objective comparison of results in clinical practice and trials.

Validation of UVEDAI: An Index for Evaluating the Level of Inflammatory Activity in Uveitis.

INTRODUCTION: Uveitis is the inflammation of the middle layer of the eye, the uvea, and is a major cause of blindness. None of the instruments used in clinical practice are, in themselves, sufficient to evaluate the course of uveitis. Therefore, it is necessary to develop instruments enabling standardized measurement of inflammatory activity. We developed a composite disease activity index for patients with uveitis known as UVEDAI, which considers the overall activity of the eye. The objective of this study was to validate the composite index of ocular inflammation, UVEDAI. METHODS: A multicenter cross-sectional study involving eight Spanish tertiary hospitals. Sixty-two patients aged ≥ 18 years with acute uveitis were recruited. Participants gave informed consent before participating in the study. A full ophthalmological examination was performed by two ophthalmologists to determine inflammatory activity: one used the UVEDAI score and the other used clinical judgment. The ophthalmologists did not share their findings with each other to avoid introducing bias into the analysis. Construct validity was established by means of factor analysis. The criterion validity of the index was determined using an ordinal multivariate regression model, in which the dependent variable was the degree of uveal inflammation (mild, moderate, or high/severe). Cut-off points were determined for the UVEDAI and for the receiver operating characteristic (ROC) curves. RESULTS: Sixty-two patients were included. Total variance with the three components accounted for 80.32% of the construct validity. Each of the three components identified one type of eye involvement. The discriminatory capacity of UVEDAI was 0.867 (95% CI 0.778; 0.955 p < 0.001) for mild versus moderate-high and 0.946 (95% CI 0.879; 1.000 p < 0.001) for high versus mild-moderate. CONCLUSIONS: The variables included in UVEDAI enable ocular inflammatory activity to be described with a high degree of accuracy. The index may be used to evaluate and classify this activity with considerable discriminatory power.

Therapeutic Response After Immunosuppressive Drug Prescription in Non-infectious Uveitis: A Survival Analysis.

INTRODUCTION: To identify factors affecting the response rate to immunosuppressive drugs (ISDs) in patients with non-infectious uveitis (NIU). METHODS: This longitudinal retrospective cohort study included patients from the Hospital Clinico San Carlos Uveitis Clinic diagnosed with NIU from 1992 to 2016. Subjects were followed up from ISD prescription until the achievement of good therapeutic response (GTR), ISD treatment change, or up to 12 months. GTR was defined as the complete resolution of the eye inflammatory manifestations with a corticosteroid dose ≤ 10 or ≤ 5 mg per day of prednisone or equivalent (GTR10 and GTR5, respectively) maintained for at least 28 days. Kaplan-Meier curves were estimated for GTR. Demographic, clinical, and treatment-related factors were analyzed using Cox robust regression. RESULTS: A total of 73 patients (100 episodes of ISD prescription) were analyzed. In 44 and 41 episodes, GTR10 and GTR5 were achieved, respectively. A lower hazard for both GTRs was associated with uveitic macular edema at prescription and with a higher "highest oral corticosteroid dose prescribed in the year before ISD prescription". GTR10 was higher if cyclosporine was prescribed (compared to other ISDs), and if a higher number of ISDs had been previously prescribed. GTR5 hazard was lower for patients with posterior uveitis or if the ISDs were prescribed before 2008, and higher if periocular corticosteroids had been administered before ISD prescription, or if the duration of the posterior segment activity was shorter. CONCLUSIONS: Factors associated with GTR to ISDs may help to identify patients with NIUs who could benefit from a thorough follow-up.

Corneal Biomechanics in Non-infectious Uveitis Measured by Corvis ST: A Pilot Study.

PURPOSE: To assess differences between corneal biomechanical properties in patients with non-infectious uveitis and healthy subjects using CorVis. METHODS: 77 patients with non-infectious uveitis and 47 control subjects were recruited. Biomechanical parameters were measured: deformation amplitude (DA), A-1 length and A-2 length (L1, L2), A-1 velocity and A-2 velocity (V1, V2), peak distance (PD) and HC radius (highest concavity radius). AUC ROC and correlation between clinical variables and biomechanical properties were determined. RESULTS: Lower HC Radius and IOPb and higher DA and V1 was found in uveitis group. Statistical differences between cases using systemic medications and those with topical treatment were found in L1. Differences were showed between those cases with active and inactive uveitis in PD, DA, V2 and L2. The biomechanical parameter with the best discriminatory capacity of uveitis disease was HC Radius. CONCLUSION: Differences in corneal biomechanical properties between non-infectious uveitis and healthy eyes were found.

Inflammatory Relapses after Immunosuppressive Drug Discontinuation in Uveitis Patients: A Survival Analysis.

Purpose: To estimate the incidence rate (IR) and identify risk factors associated to inflammatory relapse after immunosuppressive drug (ISD) discontinuation in noninfectious uveitis patients.Methods: Multicenter longitudinal retrospective study, including patients from four uveitis clinics followed-up until December 2018. Hazard ratios for different variables were estimated using multivariable Cox models.Results: 32 patients (34 episodes of ISD discontinuation) were analyzed (median and maximum follow-up time: 2.4 and 19.2 years, respectively). Fourteen patients presented at least one relapse: anterior (8 patients), intermediate (5) and posterior (8). IR (95% confidence interval) of the first relapse was 14.3 (8.6-23.8) episodes per 100 patient-years (median survival time: 4.8 years). Early use of ISDs, panuveitis, and higher oral corticosteroid dosage at discontinuation were associated with higher hazards of relapse in multivariable analysis.Conclusions: Relapse is a frequent and early event after ISD discontinuation. Identifying relapse risk factors could support the physician's decision regarding ISD discontinuation.

Visual acuity loss and development of ocular complications in white dot syndromes: a longitudinal analysis of 3 centers.

PURPOSE: To compare the clinical prognosis among selected white dot syndromes (WDS) (birdshot chorioretinopathy (BRC), multifocal choroiditis, serpiginous choroidopathy (SC), and others) and to identify risk factors of poor visual prognosis. METHODS: Retrospective longitudinal cohort study including 84 patients (143 affected eyes) diagnosed with WDS between 1982 and July 2017, followed up until loss of follow-up or December 2017, and recruited from three Uveitis Clinics (Madrid Community, Spain). Our main outcome measures were temporary or permanent moderate (corrected visual acuity in the Snellen scale < 20/50) or severe (< 20/200) vision losses, and development of new ocular complications. Incidence rates (IR) of the main outcome measures were estimated per 100 eye-years. Bivariate and multivariate Cox robust regression models analyzed the association of demographic- and clinical-related variables with vision loss. RESULTS: SC exhibited the greatest IR of vision loss, even in the multivariate models. Previous events of vision loss, presence of choroidal neovascularization, and cataracts exhibited worse visual prognosis. Monotherapy with immunosuppressive drugs but not combine therapy was also associated with higher IR of visual loss. Regarding new ocular complications, BRC showed the highest IR of epiretinal membrane and macular edema. CONCLUSIONS: SC presents the worst visual prognosis. Some ocular manifestations can identify patients with WDS at risk of a worse clinical evolution.

Disease Remission in Children and Adolescents with Intermediate Uveitis: A Survival Analysis.

PURPOSE: To report the incidence rate (IR) of remission in pediatric noninfectious intermediate uveitis (IU). METHODS: Longitudinal retrospective cohort study, including 19 patients (32 eyes) between 1985 and 2014, followed-up until loss or January 2016. Remission was defined following the Standardization of Uveitis Nomenclature workshop criteria, prolonged remission as a remission spanning 12 months and until the end of follow-up, and relapse as recurrence of inflammatory activity in an eye in remission. RESULTS: Median follow-up time was 6.3 years. IRs (95% confidence interval) for remission, relapse, and prolonged remission were 18.6 (13.1-26.5), 32.3 (20.6-50.7), and 6.7 (3.8-11.9) episodes per 100 eye-years, respectively. 48% of eyes relapsed in the first year following remission. 25 and 50% of eyes achieved prolonged remission after 5 and 10 years of follow-up, respectively. CONCLUSIONS: Inflammatory relapses may be frequent in noninfectious IU affecting children and adolescents, appearing early after remission. Also, prolonged remission seems infrequent, being achieved late during follow-up.

Dependence of dynamic contour and Goldmann applanation tonometries on peripheral corneal thickness.

AIM: To determine the effects of peripheral corneal thickness (PCT) on dynamic contour tonometry(DCT) and Goldmann applanation tonometry (GAT). METHODS: A cross-sectional study. We created a software which calculates the corneal contour (CC) as a function of the radius from the corneal apex to each pixel of the contour. The software generates a central circumference with a radius of 1 mm and the remainder of the cornea is segmented in 5 rings concentric with corneal apex being its diameter not constant around the corneal circumference as a consequence of the irregular CC but keeping constant the diameter of each ring in each direction of the contour. PCT was determined as the mean thickness of the most eccentric ring. Locally weighted scatterplot smoothing (LOWESS) regression was used to determine the pattern of the relationship between PCT and both DCT and GAT respectively. Thereafter, two multivariable linear regression models were constructed. In each of them, the dependant variable was intraocular pressure (IOP) as determined using GAT and DCT respectively. In both of the models the predictive variable was PCT though LOWESS regression pattern was used to model the relationship between the dependant variables and the predictor one. Age and sex were also introduced control variables along with their first-degree interactions with PCT. Main outcome measures include amount of IOP variation explained through regression models (R2) and regression coefficients (B). RESULTS: Subjects included 109 eyes of 109 healthy individuals. LOWESS regression suggested that a 2nd-degree polynomial would be suitable to model the relationship between both DCT and GAT with PCT. Hence PCT was introduced in both models as a linear and quadratic term. Neither age nor sex nor interactions were statistically significant in both models. For GAT model, R2 was 17.14% (F=9.02; P=0.0002), PCT linear term B was -1.163 (95% CI: -1.163, -0.617). PCT quadratic term B was 0.00081 (95% CI: 0.00043, 0.00118). For DCT model R2 was 14.28% (F=9.29; P=0.0002), PCT linear term B was -0.712 (95% CI: -1.052, -0.372), PCT quadratic term was B=0.0005 (95% CI: 0.0003, 0.0007). CONCLUSION: DCT and GAT measurements are conditioned by PCT though this effect, rather than linear, follows a 2nd-degree polynomial pattern.

The Icare-Pro Rebound Tonometer Versus the Hand-held Applanation Tonometer in Congenital Glaucoma.

PURPOSE: To compare intraocular pressure (IOP) measurements obtained using the new rebound tonometer Icare-Pro and the hand-held version of Goldmann Applanation Tonometer (Perkins tonometer) in children with primary congenital glaucoma (PCG) under general anesthesia. MATERIALS AND METHODS: Using both tonometers, 3 IOP measurements were prospectively determined in 1 single session. Icare-Pro was always used first, and then Perkins. All measurements were recruited in 50 eyes of 50 patients with PCG under general anesthesia. Central corneal thickness, anterior chamber depth, and axial length were also measured in each patient. Data were compared by determining interclass correlation coefficient for each tonometer and representing the differences detected as Bland-Altman plots. RESULTS: Good linear correlation was observed between IOP readings obtained using the Perkins and Icare-Pro (r=0.75, P<0.001), although the Icare-Pro readings were slightly higher (mean IOP difference 0.42 ± 3.69 mm Hg, P=0.41). A Bland-Altman plot revealed the 95% limits of agreement between the 2 methods: 7.7 to -6.8 mm Hg (slope=0.109, P=0.32). Intraclass correlation coefficient was 0.74 (95% confidence interval, 0.59-0.84) showing good agreement. For both tonometers, no correlation was detected between IOP measurements and central corneal thickness and axial length, but positive relation was found with anterior chamber depth. CONCLUSIONS: IOP measurements determined using the new Icare-Pro rebound tonometer showed good correlation with those obtained using the hand-held Perkins applanation tonometer in children with PCG under general anesthesia.

Correlations between corneal and optic nerve head variables in healthy subjects and patients with primary open angle glaucoma.

AIM: To correlate corneal variables (determined using the Pentacam) with optic nerve head (ONH) variables determined using the Heidelberg retina tomograph (HRT) in healthy subjects and patients diagnosed with primary open angle glaucoma (POAG). METHODS: Measurements were made in 75 healthy eyes and 73 eyes with POAG and correlations examined through Pearson correlation coefficients between the two sets of variables in the two subject groups. The corneal variables determined were corneal volume (CVol), central corneal thickness (CCT), overall corneal thickness (OvCT), the mean thickness of a circular zone centered at the corneal apex of 1 mm radius (zone I) and the mean thickness of several concentric rings, also centered at the apex until the limbus, each of 1 mm width (zones II to VI respectively). The ONH variables were determined using the HRT. RESULTS: The following pairs of variables were correlated in the control group: CCT-disc area (DAr) (-0.48; P<0.0001), Zone I-DAr (-0.503; P<0.0001) and Zone II-DAr (-0.443; P<0.0001); and in the POAG group: CCT-cup-to-disc area ratio (CDRa) (-0.402; P<0.0001), Zone I-CDRa (-0.418; P<0.0001), Zone II-CDRa (-0.405; P=0.006), Zone I-cup shape measure (CSM) (-0.415; P=0.002), Zone II-CSM (-0.405; P=0.001), Zone IV-height variation contour (HVC) (0.378; P=0.002); Zone V-HVC (0.388, P<0.0001). CONCLUSIONS: In the healthy subjects, significant negative correlation was detected between central and paracentral corneal thickness and optic disc area. In contrast, the POAG patients showed significant negative correlation between central and paracentral corneal thickness and the cup-disc ratio and CSM, and positive correlation between peripheral corneal thickness and HVC.

Interferon-associated retinopathy in a patient with metastatic melanoma.

We present the unusual case of a 35 year-old woman with stage IV melanoma and widespread metastases, who was undergoing treatment with interferon alpha-2b and who presented with interferon-associated retinopathy. The patient, who had been taking interferon treatment for three months, complained of a sudden loss of visual acuity in the left eye. An ocular examination revealed multiple cotton wool spots along the retina and macular involvement. Interferon treatment was suspended. Although rare, retinopathy represents a potentially serious adverse effect of interferon treatment. Although normally patients are asymptomatic, complications derived of its use may arise, which can lead to significant visual impairment. We therefore suggest that before initiating treatment with this drug, patients should be informed of its potential ocular risks, and that regular eye examinations are conducted along with the treatment.

Interferon-associated retinopathy in a patient with metastatic melanoma / Retinopatia relacionada ao interferon em paciente com melanoma metastático

We present the unusual case of a 35 year-old woman with stage IV melanoma and widespread metastases, who was undergoing treatment with interferon alpha-2b and who presented with interferon-associated retinopathy. The patient, who had been taking interferon treatment for three months, complained of a sudden loss of visual acuity in the left eye. An ocular examination revealed multiple cotton wool spots along the retina and macular involvement. Interferon treatment was suspended. Although rare, retinopathy represents a potentially serious adverse effect of interferon treatment. Although normally patients are asymptomatic, complications derived of its use may arise, which can lead to significant visual impairment. We therefore suggest that before initiating treatment with this drug, patients should be informed of its potential ocular risks, and that regular eye examinations are conducted along with the treatment.

Apresentamos o caso de uma mulher de 35 anos com melanoma em estágio IV e metástases generalizadas tratados com interferon alpha-2b, que proporcionou uma retinopatia associada ao interferon. Mulher de 35 anos de idade tratados com interferon durante os últimos três meses apresentou uma perda súbita da acuidade visual no olho esquerdo. Exame ocular revelou vários pontos de algodão ao longo da retina e mácula. Tratamento com interferon foi parado. Retinopatia associada ao uso de interferon está entre os possíveis efeitos colaterais, embora rara, não deve ser subestimada. Embora geralmente assintomática, complicações decorrentes de seu uso podem levar à perda visual significativa. Consideramos, portanto, que antes de iniciar o tratamento com este medicamento, os pacientes devem ser informados sobre os riscos potenciais e os exames oftalmológicos são recomendados durante cada tratamento.

Anatomical characterization of central, apical and minimal corneal thickness.

AIM: To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center) in relation to the corneal apex. METHODS: Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT), minimum corneal thickness (MT) and corneal thickness at the pupil center (PT) were determined using the pentacam. Distances from the corneal apex to MT (MD) and PT (PD) were calculated and their quadrant position (taking the corneal apex as the reference) determined: point of minimum thickness (MC) and point of central thickness (PC) depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam) and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models. RESULTS: MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant). PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI: -0.043 to -0.004). No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC. CONCLUSION: MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.

Characterization of the thickness of different corneal zones in glaucoma: effect on dynamic contour, Goldmann and rebound tonometries.

PURPOSE: To characterize five models of corneal thickness circular zoning in a sample of healthy controls and a sample of patients with primary open-angle glaucoma (POAG) and to determine their effect on Goldmann (GAT), dynamic contour (DCT) and rebound tonometers (RT). METHODS: The study participants were 122 controls and 129 cases. Five corneal thickness zoning models (A, B, C, D and E) were constructed. The partitioning pattern consisted of a circle centred at the corneal apex and several concentric rings, until the limbus; the contours of each ring followed the geometry of the corneal contour of each participant. In Model A, the central circle was 1 mm in diameter and five concentric rings were established. Mean was obtained for each zone for both samples and compared between them using a t-test. The effect on the tonometers of central cornel thickness (CCT) and mean thickness of the zones generated was determined through several linear regression models (one per tonometer and per sample). RESULTS: According to a t-test, cases and controls differ in zones I [mean difference (MD): 17.93 µm], V (MD: 25.52 µm) and VI (MD: 31.78 µm) of model A (higher values in the cases sample). RT was affected by CCT (controls: B = 0.089; cases: B = 0.081). DCT was affected by zone IV of model A (controls: B = -0.029; cases: B = -0.012). GAT was affected by CCT (controls: B = 0.043; cases: B = 0.025) and zone III of model A (controls: B = -0.045; cases: B = -0.033). CONCLUSION: Our results highlight the importance of the thickness of other regions of the cornea different from its main centre in discriminating between healthy controls and patients with POAG and in IOP measurements made using DCT, GAT and RT.

Effect of corneal morphometry on dynamic contour and Goldmann applanation tonometry.

OBJECTIVES: To determine the effects on dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) of the power of the flattest and steepest corneal meridians, their orientation, central corneal thickness (CCT), mean overall corneal thickness, and the mean thickness of a circular zone centered at the corneal apex of 1 mm radius (zone I) and the mean thicknesses of several concentric rings also centered at the apex of width 1 mm (zones II to VI, respectively). METHODS: A total of 136 consecutive healthy eyes were examined. Two multivariate linear regression models were constructed, 1 for each tonometry system. In both models, the predictive variables were: keratometric power of the flattest and steepest axes, flattest axis (as one of the categories 0 to 30, 30 to 60, 60 to 90, 90 to 120, 120 to 150, and 150 to 180 degrees), CCT, mean overall corneal thickness (determined using the Pentacam), and mean thicknesses of corneal zones I, II, III, IV, V, and VI (determined using the Pentacam). RESULTS: The multivariate regression analysis (adjusted R=0.11; P=0.04) revealed that GAT was influenced by CCT [B=0.042; 95% confidence interval (CI), 0.002-0.085] and the mean thicknesses of zones I (B=0.996; 95% CI, 0.105-1.729), II (B=-1.688; 95% CI, -3.171 to -0.204), and III (B=0.718; 95% CI, 0.028-1.407), whereas DCT was solely affected by the mean thickness of zone II (B=-0.372; 95% CI, -0.728 to -0.016) (adjusted R2=0.13; P=0.02). CONCLUSIONS: Although DCT is only affected by the mean thickness of zone II, GAT is influenced by CCT and the mean thickness of zones I, II, and III.

Effect of lubricating eyedrops on ocular light scattering as a measure of vision quality in patients with dry eye.

PURPOSE: To determine light scattering by the eye as a measure of optical quality using the Optical Quality Analysis System in patients with mild to moderate dry-eye disease and to examine change patterns after lubricating eyedrop use. SETTING: Hospital Clínico San Carlos, Madrid, Spain. DESIGN: Evaluation of diagnostic test or technology. METHODS: Eyes with mild to moderate dry-eye disease (study group) and healthy eyes (control group) were examined in a single visit. All patients completed a questionnaire to assess dry-eye disease symptoms (ocular surface disease index [OSDI]). Signs of dry eye were recorded as the tear breakup time, Schirmer I test, and corneal staining score. Scattered light was measured as the objective scatter index (OSI) at 0.5-second intervals over 20 seconds without blinking. The measurements were repeated 5, 10, 20, 30, 45, and 60 minutes after eyedrop instillation, and the OSI change rate was calculated. RESULTS: The OSI was significantly higher in the study group (25 eyes) than in the control group (10 eyes). After eyedrop instillation in the study group, the OSI change rate decreased significantly from baseline at each time point (P<.001, 45 minutes; P<.01, 60 minutes). No significant differences in the OSI change rate were detected between time points except between 45 minutes and 60 minutes (P<.01). A correlation was observed in all the dry-eye variables except the corneal staining score. CONCLUSION: Lubricating eyedrops improved ocular scattering in patients with mild to moderate dry eye for at least 60 minutes after instillation. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Comparing corneal variables in healthy subjects and patients with primary open-angle glaucoma.

PURPOSE: This study was designed to identify possible differences between healthy subjects and patients with primary open-angle glaucoma (POAG) in keratometry, central corneal thickness, overall corneal thickness, mean thickness of a circular zone centered at the corneal apex of 1-mm radius (zone I), and mean thickness of several concentric rings also centered at the apex of 1-mm width (zones II to VI, respectively). METHODS: These variables were recorded in 126 healthy subjects and 130 patients with POAG. Corneal thicknesses and the power of the flattest and steepest axes were compared between the two populations using a t-test and the position of the flattest axis using a Mann-Whitney U test. A binary logistic regression procedure was used to determine the diagnostic capacity of the corneal variables using the area under the receiver operator characteristic curve (AUC) to select the best regression equation. RESULTS: Significant differences between subjects and patients were detected in mean corneal thickness and in mean thicknesses of zones I to VI. The logistic regression model included as predictors the mean corneal thickness and the mean thicknesses of zones IV and VI; for this model, the AUC was 0.711, sensitivity was 67.7%, and specificity was 65.5%. CONCLUSIONS: Healthy subjects and glaucoma patients differ significantly in terms of mean overall corneal thickness and thicknesses of the corneal zones I to VI defined here. The variables mean corneal thickness and mean thicknesses of zones IV and VI are able to discriminate between subjects with or without glaucoma.