Chronic Primary Angle-closure Glaucoma Eyes Research Articles

Safety and efficacy of incisional goniotomy as an adjunct with phacoemulsification in primary angle-closure glaucoma.

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of incisional goniotomy as an adjunct to phacoemulsification in primary angle-closure glaucoma (PACG) patients. Consecutive patients with PACG (high or borderline IOP) deemed fit for phacoemulsification were enrolled. After phacoemulsification, incisional goniotomy was performed with or without goniosynechialysis. Patient demographic profile, clinical data, and adverse events, if any, were analyzed during at least a 6-month follow-up period. Success was defined as IOP of 18 mm Hg or lesser with or without medications. Tertiary care Ophthalmic hospital. Prospective interventional case series. Of 46 eyes (38 patients) included, 69.6% eyes were classified as having advanced glaucoma. The mean treated IOP decreased by 7.3 ± 1.0 (SE) mm Hg (95% CI, 5.2-9.3) from 21.4 ± 6.6 to 14.2 ± 3.7 mm Hg at a mean duration of 11.7 ± 5.5 months (6-22 months) postoperatively (P < .001, paired t test). There was 66.6% reduction in median number of hypotensive medications (P < .001, Wilcoxon signed-rank test). Observed complications included hyphema (13 eyes [28%]), IOP spike (3 eyes [6.5%]), and cyclodialysis (1 eye [2.17%]). High treated IOP and number of medications were significantly associated with failure in univariate analysis (P < .05, Fisher exact test). The cumulative survival probability for qualified success at 22 months was 87.8% ± 0.07 (95% CI, 0.65-0.96). Incisional goniotomy as an adjunct with phacoemulsification resulted in a significant and sustained reduction in IOP along with decrease in number of glaucoma medications in chronic PACG eyes, irrespective of the disease stage.

Biometric indicators of eyes with occult lens subluxation inducing secondary acute angle closure

BackgroundTo compare the anterior biometrics in eyes with secondary acute angle closure induced by occult lens subluxation (ASAC-LS), misdiagnosed as acute primary angle closure (APAC) at the first visit with APAC, chronic primary angle closure glaucoma (CPACG), and cataract.MethodsThis retrospective case study included 17 eyes with angel closure due to occult LS, who were misdiagnosed as APAC on their first visit, 56 APAC eyes, 54 CPACG eyes, and 56 cataract eyes. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AD) and lens thickness (LT) were recorded. Lens position (LP), relative lens position (RLP), corrected lens position (CLP) were calculated. Quantitative data were subject to one-way analysis of variance and correlation analysis. Categorical data were analyzed using the chi-squared test. Receiver operating characteristic (ROC) curves were plotted to obtain a suitable cutoff value of ocular biometrics.ResultsThe ASAC-LS patients had a longer ocular axial length than APAC and CPACG patients. Central corneal thickness of the ASAC-LS patients was not significantly different from APAC patients, but was significantly different from CPACG and cataract patients. The APAC patients had the smallest ACD, while the ASAC-LS patients had the smallest AD. The ASAC-LS patients had the largest lens thickness. According to ROC curve analysis, RLP, ACD, AD, CLP, LP had high power of discrimination.ConclusionsThis study revealed that LS secondary PAC patients had a shallower AD, thicker CCT comparing to those of APAC, CPACG and cataract patients. For patients with acute angle-closure glaucoma, it is necessary to exclude lens zonula relaxation.Trial registrationNCT03752710, retrospectively registered.

Morphological features of parapapillary beta zone and gamma zone in chronic primary angle-closure glaucoma.

To investigate the morphological features of parapapillary beta zone and gamma zone and their associated factors in eyes with chronic primary angle-closure glaucoma (CACG). The observational cross-sectional study included 65 CACG eyes and 65 non-myopic control eyes. On enhanced depth imaging of optical coherent tomography images, the area of parapapillary beta zone and gamma zone, and the peripapillary choroidal thickness at 6 sectors were measured. The optic disc ovality index and Bruch's membrane opening (BMO) shape were further calculated. Beta zone was present in 103 (79.2%) eyes and gamma zone in 29 (22.3%) eyes. Compared to control eyes, CACG was associated with larger parapapillary beta zone, female gender, and older age (P < 0.01). No significant difference was observed in axial length and peripapillary choroidal thickness between both groups (P > 0.05). In multivariate analysis, beta zone area was positively associated with older age and higher prevalence of CACG (P < 0.01), while a larger gamma zone area was associated with a smaller disc ovality index and a higher BMO ovality ratio (P < 0.01). The peripapillary choroidal thickness at six sectors was decreased with older age (P < 0.01). In mainly non-myopic subjects with or without CACG, larger parapapillary beta zone was correlated with older age and presence of glaucoma, while a larger parapapillary gamma zone was correlated with disc ovality but not with glaucoma. Parapapillary beta zone and gamma zone may play different roles in physiological and glaucomatous changes around optic nerve head.

Anterior Segment Features in Nanophthalmos With Secondary Chronic Angle Closure Glaucoma: An Ultrasound Biomicroscopy Study.

We compare anterior segment parameters and the risk of malignant glaucoma between nanophthalmos with secondary chronic angle closure glaucoma (NSCACG) and chronic primary angle-closure glaucoma (CPACG). This retrospective case-control study included 32 NSCACG (32 eyes) and 36 CPACG (36 eyes) patients. Anterior segment parameters, including anterior chamber depth (ACD) and width (ACW), pupil diameter (PD), lens vault (LV), ciliary process-ciliary process distance (CCD), angle opening distance500 (AOD500), trabecular-iris angle (TIA), trabecular-ciliary processes distance (TCPD), ciliary body max thickness (CBMT), iris convexity (IC), peripheral iris thickness (PIT), iris-zonule distance (IZD), trabecular ciliary process angle (TCPA), and anterior vault (AV), were measured by ultrasound biomicroscopy. A-scan ultrasonography measurements, including lens thickness (LT) and axial length (AL), also were reviewed. ACD, ACW, CCD, TCPD, and AL were smaller, whereas the LV, LT/AL, LV/LT, LV/ACD, LT/ACD, LV/AV, and AV/AL were larger in NSCACG compared to CPACG eyes (all Bonferroni-corrected P < 0.05). Eyes with NSCACG had a higher risk of malignant glaucoma postoperatively than eyes with CPACG (P = 0.018). Characterized by narrower anterior segment, forward movement of larger lens, more anteriorly rotated ciliary bodies, and smaller CCD, NSCACG eyes have a higher risk of malignant glaucoma than CPACG eyes.

Measurement of Structural Parameters of the Lamina Cribrosa in Primary Open-Angle Glaucoma and Chronic Primary Angle-Closure Glaucoma by Optical Coherence Tomography and Its Correlations with Ocular Parameters

Purpose: To measure lamina cribrosa thickness (LCT) and anterior lamina cribrosa surface depth (ALCSD) in primary open-angle glaucoma (POAG), chronic primary angle-closure glaucoma (CPACG), and control patients using spectral-domain optical coherence tomography (SD-OCT) and examine its association with relevant ocular parameters. Methods: In this cross-sectional study, 61 healthy volunteers (61 eyes), 65 POAG patients (65 eyes), and 55 CPACG patients (55 eyes) were recruited to obtain radial B-scans of the optic nerve head by way of enhanced depth imaging using Heidelberg SD-OCT. The obtained LCT and ALCSD were compared among the control, POAG, and CPACG groups. In addition, we evaluated the relationships of mean lamina cribrosa (LC) parameters with visual field (VF) mean deviation (MD), retinal nerve fiber layer (RNFL) thickness, intraocular pressure (IOP), and axial length. Results: The mean LCT of CPACG eyes was greater than that of POAG eyes (p = 0.003), but less than that of normal eyes (p < 0.001). The mean ALCSD of POAG and CPACG eyes was greater than that of normal control eyes (both p < 0.001). However, the mean ALCSD showed no significant difference between the POAG and CPACG groups (p = 0.073). Among all eyes, lower MD and thinner RNFL thickness were associated with a deeper and thinner LC (all p < 0.001). Conclusion: LCT is thinner in POAG compared to CPACG eyes. This is compatible with less deformation and compression of the LC in CPACG eyes, implying that the mechanisms of glaucomatous damage are different between POAG and CPACG eyes. Furthermore, VF MD and RNFL thickness were related to LCT and ALCSD in all patients.

Multiplex Cytokine Analysis of Aqueous Humor from the Patients with Chronic Primary Angle Closure Glaucoma

ABSTRACTPurpose: To compare the levels of cytokines and growth factor in aqueous humor of the patients with chronic primary angle closure glaucoma (PACG) and cataract.Methods: Aqueous humor samples were collected from 19 chronic PACG patients and compared with 14 nonglaucomatous controls presenting for cataract surgery. The levels of 27 cytokines and growth factors were measured in the aqueous samples using multiplex bead immunoassay and compared across groups.Results: Significantly higher levels of interleukin (IL)-8 (p < 0.001), eotaxin (p < 0.001), interferon gamma-induced protein (IP)-10 (p < 0.001) and macrophage inflammatory protein-1-beta (MIP-1β; p < 0.001) were observed in aqueous of chronic PACG patients compared to controls. In comparison to controls, significantly lower levels of IL-9 (p = 0.001), IL-17 (p < 0.001), tumor necrosis factor-alpha (TNF-α; p < 0.001), granulocyte–macrophage colony-stimulating factor (GM-CSF; p < 0.001), and IL-5 (p = 0.001) were observed in chronic PACG eyes. All other assayed cytokines—IL-1β, interleukin-1 receptor antagonist (IL-1rα), IL-6, IL-7, IL-10, IL-12, IL-13, IL-15, fibroblast growth factor-basic (FGF-basic), granulocyte colony-stimulating factor (G-CSF), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1-alpha (MIP-1α), and vascular endothelial growth factor (VEGF) —showed no significant difference between the groups.Conclusions: These results suggest that the aqueous cytokine levels of chronic PACG eyes differ significantly from nonglaucomatous eyes. This is the first study reporting significantly increased levels of eotaxin, MIP-1β, and IP-10 and lower levels of TNF-α, IL-5, IL-9, IL-17, and GM-CSF in chronic PACG patients, suggesting a plausible role of these inflammatory cytokines in its pathogenesis.

Long-Term Evaluation of Specular Microscopic Changes Following Nd: YAG Iridotomy in Chronic Primary Angle-Closure Glaucoma Eyes.

The aim of this study was to evaluate specular microscopy of chronic primary angle-closure glaucoma (CPACG) eyes at least 1 year after Nd:YAG iridotomy, and compare them with CPACG eyes without an iridotomy and age-matched, normal eyes. Consecutive patients of CPACG at the Glaucoma service were screened. All patients underwent slit-lamp biomicroscopy, +90 D examination, and applanation tonometry. A total of 100 eyes of 100 consecutive patients of CPACG with an Nd:YAG iridotomy performed ≥1 year before, who met all inclusion/exclusion criteria, 60 consecutive CPACG eyes without an iridotomy, and 60 age and refraction-matched control eyes were enrolled. A specular microscopy was performed in one eye of each patient by an observer masked to diagnosis. CPACG patients had a mean age of 62±8 years, a mean intraocular pressure of 18±5.3 mm Hg, a mean specular count of 2536±224 cells/mm, and mean duration after iridotomy of 3.2±2 years. There was a significant correlation of specular endothelial counts with age (r=-0.39; P<0.001) and interval after iridotomy (r=-0.25; P=0.01). CPACG eyes without an iridotomy had a mean age of 62±5 years and a mean specular count of 2469±199 cells/mm. Normal control eyes with a mean age of 61±6 years had a mean specular count of 2729±299 cells/mm. There was no significant difference in specular count between CPACG eyes with or without an iridotomy (P=0.19); however, both CPACG groups had a specular count significantly lower than controls (P=0.01 and 0.02, respectively). There was no statistically significant difference seen in polymegathism (coefficient of variation) and pleomorphism (% of hexagonal cells) in endothelial cells among the 3 groups. An Nd:YAG iridotomy in CPACG eyes did not lead to any significant changes in central corneal specular microscopy in the long term as compared with patients who did not undergo iridotomy. Eyes with CPACG, without and after an iridotomy, had a lower specular count compared with age-matched controls.

Dynamic changes of anterior segment in patients with different stages of primary angle-closure in both eyes and normal subjects.

PurposeTo compare changes in anterior segment parameters under light and dark (light-to-dark) conditions among eyes with chronic primary angle-closure glaucoma (CPACG), fellow eyes with confirmed or suspect primary angle-closure (PAC or PACS), and age-matched healthy eyes.MethodsConsecutive patients with CPACG in one eye and PAC/PACS in the fellow eye, as well as age-matched healthy subjects were recruited. Anterior segment optical coherence tomography measurements were conducted under light and dark conditions, and anterior chamber, lens, and iris parameters compared. Demographic and biometric factors associated with light-to-dark change in iris area were analyzed by linear regression.ResultsFifty-seven patients (mean age 59.6±8.9 years) and 30 normal subjects matched for age (60.6±9.3 years) and sex ratio were recruited. In regards to differences under light–to-dark conditions, angle opening distance at 500 μm (AOD500μm) and iris area during light-to-dark transition were smaller in CPACG eyes than fellow PACS/PAC eyes and normal eyes (P<0.017). Pupil diameter change was largest in normal eyes, and larger in PACS/PAC eyes than CPACG eyes (P<0.017). There was an average reduction of 0.145 mm2 in iris area for each millimeter of pupil diameter increase in CPACG eyes, 0.161 mm2 in fellow PAC/PACS eyes, and 0.165 mm2 in normal eyes. Larger iris curvature in the dark and diagnosis of PACG were significantly associated with less light-to-dark iris area changes.ConclusionsDynamic changes in iris parameters with light-to-dark transition differed significantly among CPACG eyes, fellow PAC/PACS eyes, and normal eyes. Greater iris curvature under dark conditions was correlated with reduced light-to-dark change in iris area and pupil diameter, which may contribute to disease progression.

Comparing the lamina cribrosa in eyes with primary open angle glaucoma and chronic primary angle closure glaucoma

Objective To compare the lamina cribrosa parameters between primary open angle glaucoma (POAG) and chronic primary angle closure glaucoma (CPACG) eyes. Methods A total of 73 POAG eyes (73 subjects), 64 CPACG eyes (64 subjects), and 40 normal control eyes (40 subjects) with matched ages were included in this cross-sectional observational study. No significant difference was found in sex (χ2=2.07) and age (F=0.38) among three groups (P>0.05). The intraocular pressure, average retinal nerve fiber layer (RNFL) thickness and average visual field defect were not significantly different between POAG and CPACG patients (F=15.67, 21.15, 44.40, 27.99; P<0.05). All subjects underwent spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging (EDI). The optic nerve head was scanned radially at the angle of 20; six high resolution B-scan images were obtained from each eye. The center and para-center lamina cribrosa thickness (LCT) and anterior lamina cribrosa surface depth (ALCSD) were measured in each image. The mean LCT and ALCSD were recorded as the average of the LCT and ALCSD of the 6 images and compared among POAG, CPACG and normal control eyes. Results The average LCT of normal control eyes were (211.48±12.07) μm, while those of the POAG eyes were (145.43±34.33) μm, CPACG eyes were (156.79±33.66) μm. The mean LCT of the POAG and CPACG eyes were thinner than those of the control eyes (t=-11.76, -9.88; P<0.01). All LCT of the POAG eyes were significantly thinner than those of the CPACG eyes (t=-1.96, P=0.03). The average ALCSD of normal control eyes were (390.73±84.40) μm, while those of the POAG eyes were (558.51±176.66) μm, CPACG eyes were (539.39±177.30) μm, respectively. The average ALCSD of the POAG and CPACG eyes were deeper than those of the control eyes (t=5.65, 4.96; P<0.01). But no significantly different ALCSD was shown between POAG and CPACG eyes (t=0.63, P=0.49). Conclusions POAG and CPACG eyes have thinner LCT and deeper ALCSD than normal eyes. POAG eyes have thinner LCT than CPACG eyes when their visual field defect and damage of RNFL were in the same degree. Key words: Glaucoma, open-angle/diagnosis; Glaucoma, angle-closure/diagnosis; Tomography, optical coherence

A prospective comparison of chronic primary angle-closure glaucoma versus primary open-angle glaucoma in Singapore

To describe the optic disc, visual field and ocular characteristics of a consecutive cohort of Asian patients with chronic primary angle-closure glaucoma (CPACG), and compare them with those having primary open-angle glaucoma (POAG). In a prospective comparative case series of new patients with POAG or CPACG in Singapore, all patients underwent visual acuity assessment, slit-lamp examination, tonometry, gonioscopy, refraction, Heidelberg Retina Tomograph (HRT) and Humphrey visual field (HVF) assessment. 98 patients were enrolled (POAG n = 48; CPACG n = 50). CPACG patients were significantly older (66.5 ± 9.2 years vs. 64.1 ± 13.5 years; p = 0.027) and mostly female (p = 0.004). CPACG eyes had significantly higher intraocular pressure (26.9 ± 6.9 mmHg vs. 24.5 ± 3.3 mmHg; p = 0.03), shorter axial length (22.89 ± 0.97 mm vs. 24.26 ± 1.79 mm; p < 0.001) and shallower anterior chamber depth (2.60 ± 0.25 mm vs. 3.16 ± 0.48 mm; p < 0.001). HVF mean deviation or pattern standard deviation (PSD) did not differ significantly between POAG and CPACG eyes, but the latter had a lower PSD for a given mean deviation. HRT parameters between the two groups were not significantly different. In this study, CPACG eyes had significantly higher presenting intraocular pressure than POAG eyes, but there were no significant differences in optic disc topography. A majority of the patients in both groups had moderate field defects at the time of presentation, followed by severe and then mild defects. The field loss in CPACG eyes was more diffuse than that in POAG eyes.

The damage patterns of retinal nerve fiber layer in acute and chronic intraocular pressure elevation in primary angle closure glaucoma.

To observe the differences of damage patterns of retinal nerve fiber layer (RNFL) between acute and chronic intraocular pressure (IOP) elevation in primary angle closure glaucoma (PACG) using optical coherence tomography (OCT). Twenty four patients (48 eyes) with unilateral acute PACG (APACG) attack in the 6 months after remission and 36 patients (64 eyes) with chronic PACG (CPACG) were included in this prospective study. For all cases, IOP has been controlled less than 21 mm Hg after treatment. Using stratus OCT, the RNFL thickness was assessed in eyes with PACG within 3 days, 2 weeks, 1, 3 and 6 month after IOP controlled. Repeated measures ANOVA was used to examine the time course of changes after IOP controlled in RNFL thickness in both acute attack and unaffected fellow eyes of APACG and eyes with CPACG. The mean RNFL thickness (μm) for the APACG-attacked eyes increased significantly within 3 days (121.49±23.84) after acute strike and then became thinner along with time (107.22±24.72 at 2 week, 93.58±18.37 at 1 month, 84.10±19.89 at 3 month and 78.98±19.17 at 6 month). In APACG-attacked eyes, there were significant differences of average RNFL thickness among 5 different times after IOP was controlled (P ＜ 0.001). In the APACG unaffected fellow eyes and CPACG eyes, there were no significant differences in mean RNFL thickness among 5 different times (F = 0.450, P = 0.104 in APACG unaffected fellow eyes and F = 1.558, P = 0.200 in CPACG eyes). There was significant difference for interaction between time periods and groups (F = 1.912，P = 0.003). RNFL damage patterns are different under different IOP elevated courses. In APACG, RNFL was found to be swollen and thickening right after acute attack and then becomes thinning and atrophy along with the time, while RNFL was found to be diffused thinness in CPACG.

Damage patterns of retinal nerve fiber layer in acute and chronic intraocular pressure elevation in primary angle closure glaucoma.

To observe the differences of damage patterns of retinal nerve fiber layer (RNFL) between acute and chronic intraocular pressure (IOP) elevation in primary angle closure glaucoma (PACG) using optical coherence tomography (OCT). Twenty-four patients (48 eyes) with unilateral acute PACG (APACG) attack in the 6 months after admission and 36 patients (64 eyes) with chronic PACG (CPACG) were included in this prospective study. For all cases, IOP has been controlled under 21mmHg after treatment. Using stratus OCT, the RNFL thickness was assessed in eyes with PACG within 3 days, 2 weeks, 1, 3 and 6 months after IOP was controlled. Repeated measures ANOVA was used to examine the changes of RNFL thickness at different time after IOP being controlled in both acute attack eyes and unaffected fellow eyes of APACG and eyes with CPACG. The mean RNFL thickness for the APACG-attacked eyes increased significantly within 3 days (121.49±23.84)µm after acute onset and then became thinner along with time [(107.22±24.72)µm at 2 weeks,(93.58±18.37)µm at 1 month, (84.10±19.89)µm at 3 months and (78.98±19.17)µm at 6 months]. In APACG-attacked eyes, there were significant differences of average RNFL thickness at 5 different times after IOP was controlled (P<0.001). In the APACG unaffected fellow eyes and CPACG eyes, there were no significant differences in mean RNFL thickness at 5 different times(F=0.450, P=0.104 in APACG unaffected fellow eyes and F=1.558, P=0.200 in CPACG eyes). There was significant difference for interaction between time periods and groups (F=1.912, P=0.003). RNFL damage patterns are different under different IOP elevated courses. In APACG, RNFL was found to be swollen and thickening right after acute attack and then becomes thinning and atrophy along with the time, while RNFL was found to be diffused thinness in CPACG.

Recovery of Corneal Hysteresis After Reduction of Intraocular Pressure in Chronic Primary Angle-Closure Glaucoma

To measure corneal hysteresis (CH) in unilateral chronic primary angle-closure glaucoma (CPACG) patients to determine if it was affected by high intraocular pressure (IOP). Prospective interventional case series. CH and Goldmann-correlated IOP (IOPg) were obtained with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Dephew, New York, USA) and central corneal thickness (CCT) was measured by optical coherence tomography. Baseline CH, IOPg, and CCT were measured in 40 CPACG eyes and compared to the fellow eyes and 40 normal controls. Reduction of IOPg in CPACG eyes was achieved medically, followed by trabeculectomy and peripheral iridectomy. Measurements were repeated at 2 and 4 weeks posttherapy. IOPg decreased significantly from 31.55 +/- 10.48 mm Hg (mean +/- standard deviation) before therapy to 11.47 +/- 4.71 mm Hg, and CH increased significantly from 6.83 +/- 2.08 mm Hg to 9.22 +/- 1.80 mm Hg at 2 weeks, with no further changes after that. However, the CH in the treated eyes remained significantly lower compared with that of fellow and normal eyes. Before treatment, CH was negatively correlated with IOPg; however, there was no correlation after treatment. CCT was not affected by the reduced IOPg in the CPACG eyes. CH was significantly lower in CPACG patients, and partial recovery occurred after successful IOP-lowering therapy. Alternations affecting corneal biomechanical properties appear to occur during glaucoma development.

Correlation of previous acute angle-closure attack with extent of synechial angle closure in chronic primary angle-closure glaucoma patients

To document any correlation between previous acute angle-closure attack and the extent of synechial angle closure in chronic primary angle-closure glaucoma (PACG) patients. Consecutive cases of chronic PACG with patent peripheral iridotomy had gonioscopy performed. The extents of synechial angle closure of those chronic PACG eyes with previous documented acute angle-closure attack were compared to those eyes without such a history. A total of 102 chronic PACG eyes of 102 patients were recruited. Twenty-seven eyes (26.5%) had a previous documented acute angle closure, while 75 eyes (73.5%) did not. The mean extent of synechial angle closure +/-1 SD was 307+/-68 degrees (range, 150-360 degrees) in those chronic PACG eyes with a history of previous acute angle closure, compared to 266+/-89 degrees (range, 90-360 degrees) in those chronic PACG eyes without such a history (P=0.03, Student's t-test). There were no statistically significant differences between the two groups in age, LogMAR visual acuity, intraocular pressure (IOP), number of glaucoma eye drops, vertical cup-to-disk ratio, mean deviation or pattern SD in Humphrey automated perimetry, and anterior chamber depth (P>0.05). Previous acute angle-closure attack correlated with more extensive synechial angle closure in chronic PACG patients in this study.

Comparing glaucomatous optic neuropathy in primary open angle and chronic primary angle closure glaucoma eyes by optical coherence tomography

To comparatively evaluate the optic nerve head (ONH) using Optical Coherence Tomography (OCT) in normal subjects, primary open angle glaucoma (POAG) and chronic primary angle closure glaucoma (CPACG) patients. A total of 138 normal eyes (138 subjects) and 139 glaucomatous eyes (139 patients), were evaluated in this cross-sectional observational study. The ONH was imaged on OCT using the optic disc scan. Disc area, cup area, rim area, vertical integrated rim area (VIRA), rim volume (horizontal integrated rim volume), average cup/disc ratio, horizontal and vertical cup/disc ratios, and cup volume were evaluated. Additionally, cup depth and slope of the temporal ONH were also measured. These ONH parameters were compared between normal subjects and eyes with early POAG and CPACG. Correlation of mean deviation and corrected pattern standard deviation on full threshold 30-2 perimetry, with measured ONH parameters was carried out amongst the two groups. There was a significant difference in disc area (2.38 +/- 0.5, 2.77 +/- 0.4, 2.62 +/- 0.4 mm(2), p < 0.01), cup area (0.88 +/- 0.6, 1.99 +/- 0.7, 1.60 +/- 0.7 mm(2), p < 0.01), rim area (1.48 +/- 0.4, 0.86 +/- 0.4, 0.96 +/- 0.4 mm(2), p < 0.01), VIRA (1.64 +/- 0.3, 1.23 +/- 0.3, 1.22 +/- 0.4 mm(2), p < 0.01), rim volume (0.34 +/- 0.2, 0.1 +/- 0.1, 0.15 +/- 0.1 mm(3), p < 0.01) and cup/disc ratio (0.36 +/- 0.2, 0.69 +/- 0.1, 0.63 +/- 0.2, p < 0.01) in normal vs POAG vs CPACG eyes respectively. A comparison of ONH parameters between early POAG and early CPACG showed a significant difference in the disc area (2.85 +/- 0.3, 2.57 +/- 0.4 mm(2), p = 0.03), cup area (2 +/- 0.5, 1.34 +/- 0.5 mm(2), p < 0.01), rim area (0.96 +/- 0.4, 1.21 +/- 0.5 mm(2), p = 0.009), rim volume (0.12 +/- 0.1, 0.18 +/- 0.1 mm(3), p < 0.01) and cup/disc ratio (0.67 +/- 0.1, 0.53 +/- 0.2, p < 0.01). The parameters with the highest area under the receiver operator characteristic (AROC) curves for differentiating normal and early POAG eyes were rim volume, 0.89, VIRA, 0.84, and rim area, 0.76. The AROC values (normal vs early CPACG eyes) were 0.75 for rim volume, 0.72 for VIRA, and 0.66 for rim area. OCT may serve as a useful diagnostic modality in distinguishing a normal optic disc from a glaucomatous one, even in the early stages of glaucoma. Rim volume, VIRA and rim area can be used to differentiate normal from early glaucoma (both early POAG and CPACG), and most efficiently early POAG eyes. CPACG eyes have smaller discs, a smaller cup, smaller cup/disc ratio, and a larger rim area when compared with eyes with POAG.