Videographic measurements of optic nerve topography in glaucoma

Topographic measurements of the optic nerve head were made with computerized videographic image analysis (Rodenstock Analyzer) in one eye each of 36 normal controls, 41 glaucoma suspects and 46 glaucoma patients matched for age. Glaucoma suspects had elevated intraocular pressures and normal visual fields in both eyes. Glaucoma patients had typical visual field defects. Disc measurements were corrected for the optical dimensions of individual eyes. One-way analysis of variance revealed statistically significant differences among the diagnostic groups for cup-disc ratio (P = 0.0006), disc rim area (P less than 0.0001) and cup volume (P = 0.0001). Mean (+/- SEM) disc rim area was 1.14 +/- 0.04 mm2 for controls, 1.10 +/- 0.04 mm2 for glaucoma suspects and 0.87 +/- 0.05 mm2 for glaucoma patients. Mean (+/- SEM) optic nerve cup volume was 0.35 +/- 0.02 mm3 for controls, 0.44 +/- 0.04 mm3 for glaucoma suspects and 0.60 +/- 0.05 mm3 for glaucoma patients. Planimetric measurements of disc rim area were made from manual tracings of stereoscopic disc photographs of the same eyes. There was a statistically significant correlation between the computerized videographic measurements and the manual photographic measurements of disc rim area (r = 0.73, P less than 0.0001). The broad range of values for these optic nerve structural parameters in normal eyes and their overlap with values in glaucomatous eyes prevents their use to reliably predict which patients are normal and which have glaucomatous visual field loss. New parameters are required to fully describe the depth information generated with new quantitative techniques.     

Optic nerve blood flow is diminished in eyes of primary open-angle glaucoma suspects.

PURPOSE: The purpose of this study was to evaluate optic nerve blood flow in primary open-angle glaucoma suspect eyes with normal automated visual fields, in an attempt to elucidate how early in the glaucomatous disease process changes in optic nerve blood flow become apparent. METHODS: Twenty-one eyes (21 patients) suspected of having primary open-angle glaucoma were studied prospectively and compared with a previously reported cohort of 22 eyes (22 patients) with primary open-angle glaucoma and 15 eyes (15 subjects) of age-matched controls. Primary open-angle glaucoma suspect eyes had untreated intraocular pressure greater than 21 mm Hg and normal visual fields using Humphrey program 24-2 or 30-2 with a full threshold strategy. Laser Doppler flowmetry was used to measure optic nerve head blood velocity, volume, and flow at four quadrants in the optic nerve, in the cup, and in the foveola of one eye of each patient. The mean flow from the superotemporal rim, inferotemporal rim, and cup was calculated (Flow(3)) and identified as the main outcome measure. Measurements from primary open-angle glaucoma suspect eyes were compared with corresponding measurements from controls and eyes with primary open-angle glaucoma; a Student t test was employed with a Bonferroni corrected P value of.025 to account for comparisons of primary open-angle glaucoma suspects both to controls and to eyes with primary open-angle glaucoma. RESULTS: Compared with controls, Flow(3) was 24% lower in primary open-angle glaucoma suspect eyes (P <.0003). In primary open-angle glaucoma suspect eyes, flow was 16% lower in the superotemporal rim (P <.007), 35% lower in the cup (P <.007), and 22% lower in the inferotemporal neuroretinal rim (P <.029) compared with controls. No significant difference between primary open-angle glaucoma suspect and control eyes was seen in the inferonasal rim, superonasal rim, or foveola. No significant difference was detected at any location between primary open-angle glaucoma suspect eyes and eyes with primary open-angle glaucoma. CONCLUSIONS: Laser Doppler flowmetry detected circulatory abnormalities in primary open-angle glaucoma suspects who did not have any manifest visual field defect. Decreases in flow in glaucoma suspects were similar in magnitude to those of subjects with primary open-angle glaucoma. These data suggest that impaired optic nerve blood flow develops early in the glaucomatous process and does not develop solely as a result of glaucoma damage.     

Correlation of structure and function in glaucoma. Quantitative measurements of disc and field

The relationship between quantitative structural measurements of the optic nerve head and quantitative measurements of the visual field in glaucoma was studied. Computerized videographic image analysis (Rodenstock Analyzer) was used to obtain cup-disc ratio, disc rim area, and cup volume in 50 glaucoma suspects and 37 glaucoma patients. The visual field indices, mean defect and loss standard deviation, were calculated from Octopus Program 32. There were statistically significant linear correlations between each of the optic nerve structural parameters and visual field mean defect and loss standard deviation. The strongest correlation was between disc rim area and visual field mean defect (r = -0.49), which are both global measures of glaucomatous damage. The correlations were not strong enough to readily allow the recognition of early nerve damage by the parameters analyzed thus far. Closer correlations may be evident if structural parameters can be found that more accurately reflect the number of surviving axons in the optic nerve head.     

Disc and field damage in patients with unilateral visual field loss from primary open-angle glaucoma

To assess the temporal relationship between field and disc change in early glaucoma, 24 patients with unilateral visual field loss from primary open angle glaucoma were identified for planimetric optic disc measurements. Cross-sectional analysis of disc rim area was performed and compared to 25 age-matched normal controls. The mean (±SD) disc rim area in eyes with normal visual fields (1.10 ± 0.31 mm²) was slightly larger than that of eyes with visual field loss (0.90 ± 0.33 mm²). The mean disc rim area in the control group (1.49 ± 0.19 mm²) was significantly different from both sets of eyes in the asymmetric primary open angle glaucoma patients (p = 0.000). These findings support the hypothesis that loss of the optic disc rim can be detected before perimetric abnormalities develop in patients with glaucoma.     

Morphology of the optic papilla in glaucoma. II. Secondary chronic open angle glaucoma

Previous studies have shown that the chronic open-angle glaucomas form a heterogeneous spectrum of diseases which have in common an open anterior chamber angle and glaucomatous optic nerve damage. Purpose of this study was to evaluate whether the appearance of the optic disc shows specific features among various types of secondary chronic open-angle glaucoma. METHODS: Clinical data and color-stereo optic disc photographs of 126 patients with pseudoexfoliative glaucoma and 47 patients with pigmentary glaucoma were compared with those of 501 patients with primary open-angle glaucoma (POAG) and of 481 normal subjects. The glaucoma groups did not differ in neuroretinal rim nor in perimetric mean defect. RESULTS: Mean optic disc area was significantly smaller in the pseudoexfoliative glaucoma eyes (2.54 +/- 0.51 mm2 vs. 2.71 +/- 0.63 mm2, p = 0.03) than in the primary open-angle glaucoma eyes. The pigmentary glaucoma group did not vary significantly from the primary open-angle glaucoma group in size of the optic disc. No significant differences were found for neuroretinal rim area, configuration of neuroretinal rim, depth of optic cup and diameters of the retinal arterioles and venules at the disc border between the secondary glaucoma groups and the POAG group respectively. Size of zone beta of the parapapillary atrophy was slightly, but not significantly smaller in the secondary glaucoma groups than in POAG. In the secondary glaucoma groups, the maximal intraocular pressure measurements were significantly (p < 0.001) higher than in the group with POAG. All glaucoma groups had a significantly smaller neuroretinal rim, significantly smaller retinal arterioles, and significantly larger parapapillary atrophy compared to the normal group. CONCLUSIONS: Except of a slightly smaller optic disc in eyes with pseudoexfoliative glaucoma, eyes with secondary glaucoma due to pseudoexfoliation or due to pigmentary dispersion do not vary significantly in their optic disc morphology compared to POAG and do not show pathognomonic features of the optic disc despite marked changes in the anterior segment of the eye.     

Anisometropia and degree of optic nerve damage in chronic open-angle glaucoma

PURPOSE: To address the question of whether the refractive error plays a role in the amount of optic nerve damage in glaucoma, we intraindividually compared inter-eye differences in refractive error with inter-eye differences in parameters indicating the degree of glaucomatous optic nerve damage, and we interindividually correlated refractive error with neuroretinal rim area and visual field loss.DESIGN: Comparative clinical observational study.METHODS: This comparative clinical observational study was conducted in a university eye hospital. The study included 1,444 eyes of 876 patients with primary or secondary chronic open-angle glaucoma. Patients with a highly myopic refractive error (> or = -8 diopters) were excluded, owing to differences in the anatomy of the optic nerve head. Color stereo optic disk photographs were taken and morphometrically evaluated. The main outcome measures were refractive error, neuroretinal rim area, horizontal and vertical cup/disk diameter ratios, and visual field loss.RESULTS: In an interindividual statistical analysis, area of neuroretinal rim, horizontal and vertical cup/disk diameter ratios, and mean visual field loss were not significantly (P >.10) correlated with refractive error. In an intraindividual comparison, inter-eye differences in refractive error were not significantly (P >.05) correlated with inter-eye differences in neuroretinal rim area and mean visual field defect. The eye with the more myopic refractive error and the contralateral eye with the less myopic refractive error did not vary significantly in neuroretinal rim area and mean visual field defect.CONCLUSIONS: For nonhighly myopic (< -8 diopters) patients with primary or secondary chronic open-angle glaucoma, the refractive error may not play a major role for the amount of glaucomatous optic neuropathy. For nonhighly myopic (< -8 diopters) patients with primary or secondary chronic open-angle glaucoma, myopia may not be an important risk factor for glaucoma.     

Intraocular pressure-related pattern of optic disc cupping in adult glaucoma patients

The pattern of glaucomatous optic disc cupping was investigated in 67 eyes of 67 primary open-angle glaucoma patients with early-to-moderate visual field loss and a wide range of intraocular pressure. We determined the position of the deepest point of the optic disc cup using the Rodenstock Analyzer. This position correlated significantly with intraocular pressure: the deepest point tended to be located below the center of the optic disc at high intraocular pressure and above the center at low intraocular pressure. There was no significant correlation between the position of the deepest cup point along the horizontal axis and intraocular pressure. The position of the deepest point of the cup also correlated significantly with the severity of glaucoma, albeit less strongly than with intraocular pressure: it tended to be in the inferior portion of the disc at an early stage of glaucoma and in the superior portion of the disc at a more advanced stage of glaucoma. Therefore, the inferior portion of the optic nerve head appears to be most yielding to changes of intraocular pressure. These findings are consistent with histologic evidence of the least connective tissue support in the inferoperipheral region of the lamina cribrosa and with greater prevalence of inferior rim loss and corresponding superior visual field defects in early to moderately advanced primary open-angle glaucoma patients.Presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology, Sarasota, Florida, 28 April–3 May 1991; the authors have no proprietary interest in the Rodenstock Optic Nerve Head Analyzer Correspondence to: D.H. Shin     

Topography and fluorescein angiography of the optic nerve head in primary open-angle and chronic primary angle closure glaucoma.

PURPOSE: The purpose of this study is to correlate optic nerve head topography with fluorescein angiography of the optic nerve head in patients with primary open-angle glaucoma (POAG), chronic primary angle closure glaucoma (CPACG), and normal controls. METHODS: This was an institution-based, cross-sectional, case-control study of 30 consecutive patients each with POAG or CPACG, which were compared with 30 age- and sex-matched controls. The fluorescein angiograms undertaken in one eye of each of the 90 subjects were then analyzed both qualitatively and quantitatively. RESULTS: The mean age of controls (group 1) was 51.73 +/- 9.6 years, patients with CPACG (group II) was 53.26 +/- 9.5 years, and patients with POAG (group III) was 54.5 +/- 10.4 years. The mean deviation and corrected pattern standard deviation on Humphrey visual field analyzer, respectively, were -1.51 +/- 2.01 dB and 2.09 +/- 1.04 dB the in control group, -9.4 +/- 9.3 dB and 5.32 +/- 4.02 dB in the CPACG group, and -11.27 +/- 7.7 dB and 7.57 +/- 5.34 dB in the POAG group. There was no significant difference in the disc areas between the three groups (analysis of variance [ANOVA], p = 0.157). All circulatory parameters were delayed in both glaucoma groups compared with controls with the disc filling time (ANOVA, p = 0.001) and the choroidal filling time being significantly delayed (ANOVA, p = 0.006). The Moorfield regression analysis showed good correlation with the pattern of disc fluorescence in all quadrants in cases of CPACG and POAG. CONCLUSION: The optic nerve head and choroidal circulation was delayed in both patients with POAG and those with CPACG, which correlates with loss of neuroretinal rim and retinal nerve fiber layer on the Heidelberg Retina Tomograph II (HRT). Patients with POAG showed diffuse damage with significant rim loss, whereas patients with CPACG showed marked sectorial abnormalities (superotemporal and the inferior-temporal) on fluorescein angiography and HRT. One possible reason for this discrepancy could be sectorial ischemia occurring in cases of CPACG as a result of a sudden rise of intraocular pressure causing disc and visual field damage.     

原发性开角型青光眼HRT视盘参数和视野缺损的关系

目的 :探讨原发性开角型青光眼视盘参数和视野平均缺损之间的关系。方法 :用海德堡视网膜断层扫描仪和自动视野计测定 5 5名原发性开角型青光眼患者的视盘参数 (杯盘面积比、盘沿面积、盘沿容积、视杯容积、视杯形态测量、视杯高度变异轮廓和平均神经纤维层厚度 )和静态光阈值。视盘参数与视野平均缺损作相关分析和多元线性回归分析。结果 :盘沿面积与平均缺损显著相关 (r =0 3 5 0 ,P <0 0 5 )。盘沿面积每减少 1mm2 ,视野缺损绝对值增加 8 0 81dB。本研究没有发现其它 6个参数与平均缺损相关关系的显著性。结论 :盘沿面积在HRT众多参数中最能反映青光眼的视野平均缺损程度。     

Predictive factors of the optic nerve head for development or progression of glaucomatous visual field loss

PURPOSE: To evaluate which morphologic features of the optic disc are predictive factors for the development or progression of visual field loss in chronic open-angle glaucoma. METHODS: The prospective observational clinical study included 763 eyes of 416 white subjects with ocular hypertension and chronic open-angle glaucoma. During the follow-up time (mean, 67.4 months; median, 65.1; range, 6.2-104.5), all patients underwent repeated qualitative and morphometric evaluation of color stereo optic disc photographs and white-on-white visual field examination. Progression of glaucomatous visual field damage was defined by point-wise regression analysis for each of the 59 locations in the visual field. Outcome measures were qualitative and quantitative morphologic optic nerve head parameters. RESULTS: Development or progression of glaucomatous visual field defects was detected in 106 (13.9%) eyes. At baseline of the study, neuroretinal rim area was significantly (P < 0.002) smaller, the beta zone of parapapillary atrophy (P < 0.003, nasal sector) was significantly larger, and age was significantly higher (P < 0.003) in the progressive study group than in the nonprogressive study group. Both study groups did not vary significantly in size of the optic disc and the alpha zone of parapapillary atrophy. Cox proportional hazard regression analysis revealed that the progression of glaucomatous visual field loss depended significantly on the area of the neuroretinal rim (P < 0.001) and age (P < 0.001), but was independent of diameter of the retinal arterioles and veins. CONCLUSIONS: Morphologic predictive factors for development or progression of glaucomatous visual field defects in whites are small neuroretinal rim area and large beta zone of parapapillary atrophy. Age is an additional nonmorphologic parameter. Progression of glaucomatous optic nerve head changes is independent of the size of the optic disc and alpha-zone of parapapillary atrophy and retinal vessel diameter.     

Intravascular oxygen saturation in retinal vessels in normal subjects and open-angle glaucoma subjects

PURPOSE: To measure the oxygen saturation (SO(2)) in retinal arterioles and venules in patients with glaucomatous optic neuropathy. METHODS: We examined SO(2) in retinal arterioles and venules simultaneously by imaging spectrometry. Oxygen saturation was evaluated according to the difference of the extinction spectra of haemoglobin and oxyhaemoglobin. The arterio-venous difference (avD) was calculated by (SO(2art) - SO(2ven)). The optic nerve head topography was estimated by Heidelberg retinal tomography and the visual field using the Octopus G1. We examined one eye in each of 58 healthy persons (mean age 58.6 +/- 10.7 years; mean rim area 1.52 +/- 0.33 mm(2); mean defect 0.65 +/- 1.31 dB; mean intraocular pressure [IOP] 18.5 +/- 2.7 mmHg), 49 patients with normal-tension primary open-angle glaucoma (NTG) (mean age 63.0 +/- 8.5 years; mean rim area 0.89 +/- 0.34 mm(2); mean defect 5.4 +/- 4.1 dB; mean IOP 19.2 +/- 2.9 mmHg), and 45 patients with high-tension primary open-angle glaucoma (POAG) (mean age 62.6 +/- 10.3 years; mean rim area 0.97 +/- 0.47 mm(2); mean defect 7.1 +/- 6.4 dB; mean IOP 31.6 +/- 10.8 mmHg). RESULTS: The intraclass correlation coefficients of the SO(2) measurement were 0.82 (arteriole) and 0.59 (venule). In normal eyes, the SO(2art), SO(2ven) and avD were 92.3 +/- 3.4%, 55.7 +/- 6.8% and 36.6 +/- 7.0%, respectively. Equivalent data were 89.7 +/- 5.4%, 56.0 +/- 8.3% and 33.7 +/- 10.6%, respectively, in NTG eyes and 91.4 +/- 4.0%, 58.3 +/- 10.5% and 33.1 +/- 11.5%, respectively, in POAG eyes. Over all examined eyes, the arteriolar SO(2) and the retinal arterio-venous difference correlated significantly with the rim area. CONCLUSION: Eyes with NTG showed significantly decreased arteriolar SO(2). These changes were not seen in POAG patients.     

Iris colour, optic disc dimensions, degree and progression of glaucomatous optic nerve damage

PURPOSE: To evaluate whether iris colour influences size and shape of the optic nerve head and risk for glaucoma progression. METHODS: The hospital-based observational study included 1973 eyes of 1012 Caucasian subjects with ocular hypertension or chronic open-angle glaucoma. For all patients, colour stereo optic disc photographs were evaluated, and corneal pachymetry and achromatic perimetry were performed. Main outcome measures were optic nerve head parameters, the development or progression of visual field defects and iris colour. RESULTS: In most of the study groups, size of the optic disc, neuroretinal rim, alpha zone and beta zone of parapapillary atrophy, retinal vessel diameter and central corneal thickness did not differ significantly between eyes with blue, green, brown and mixed iris colour. In the normal-pressure glaucoma group, neuroretinal rim area was smallest in the population with mixed-coloured eyes and largest in the group of eyes with brown irides (P = 0.001 after correction for inter-eye dependency and multiple testing). For the ocular hypertensive subjects and glaucoma patients with follow-up examinations, the rate of development or progression of glaucomatous visual field loss was not significantly associated with iris colour (P = 0.060). CONCLUSIONS: In Caucasian subjects, iris colour does not have a major association with the size of the optic nerve head structures, central corneal thickness and retinal arterial diameter. In Caucasian patients with ocular hypertension or chronic open-angle glaucoma, an influence of iris colour on the risk for development or progression of glaucomatous visual field defects could not be confirmed.     

Inter-eye differences in chronic open-angle glaucoma patients with unilateral disc hemorrhages

OBJECTIVE: Flame-shaped optic disc hemorrhages are a hallmark of glaucomatous optic neuropathy. The purpose of this study was to evaluate which parameters differ between companion eyes with and without an optic disc hemorrhage in patients with chronic open-angle glaucoma. DESIGN: Comparative (companion eye) observational case series. PATIENTS: The study included 99 white patients with bilateral chronic open-angle glaucoma and unilateral flame-shaped optic disc hemorrhages. METHODS: All patients underwent qualitative and morphometric evaluation of color stereo optic disc photographs. MAIN OUTCOME MEASURES: Size and shape of the optic disc, neuroretinal rim and parapapillary atrophy, diameter of the retinal vessels, intraocular pressure measurements, and both mean value and loss variance value of the visual field examination. RESULTS: In an intraindividual inter-eye comparison, the eyes with disc hemorrhages and the contralateral eyes without disc bleeding did not vary significantly (P > 0.20) in size and shape of the optic disc and neuroretinal rim, optic cup depth, size of alpha and beta zone of parapapillary atrophy, retinal vessel diameter, intraocular pressure measurements, refractive error, and perimetric indices. CONCLUSIONS: In bilateral chronic open-angle glaucoma, the development of unilateral optic disc hemorrhages does not depend on inter-eye differences in size and shape of the optic disc, neuroretinal rim and parapapillary atrophy, diameter of the retinal vessels, intraocular pressure measurements, or visual field loss.     

Is the ISNT rule violated in early primary open-angle glaucoma--a scanning laser tomography study

AIMS: To evaluate the relevance of the ISNT rule with reference to the optic nerve head, in differentiating normal and early glaucoma eyes and neuroretinal rim (NRR) area ratios as measures of glaucomatous optic neuropathy by confocal scanning laser ophthalmoscopy (Heidelberg retina tomography (HRT) II). METHODS: The study included 136 control eyes and 63 eyes of early primary open-angle glaucoma. Each patient underwent a complete ophthalmic examination, HRT II (software 2.01) and achromatic automated perimetry using the Humphrey field analyzer Full threshold program 30-2 or 24-2. Topographic HRT parameters (disc area and rim area) were compared between the groups. To assess the statistical significance of differences between the study groups, the Student's t-test was used. RESULTS: The ISNT rule was applicable in 71% of normal eyes and 68% of early glaucoma eyes. The superior to inferior area ratio was 0.96+/-0.01 in the normal group and 0.90+/-0.02 in the glaucoma group. There was a loss of approximately a quarter of the NRR in the inferotemporal and superotemporal quadrants. The inferonasal sector showed the least loss of NRR (4.34%). CONCLUSION: The inferior NRR is marginally wider than the superior NRR in about 2/3 of normal eyes, but could not be clinically appreciated in many of these. The characteristic configuration of a normal optic disc with the rim width being greatest in the inferior disc region followed by the superior disc region was maintained even in most patients with early glaucoma.     

Patterns of early visual field loss in open-angle glaucoma

We examined two groups of patients with primary open-angle glaucoma with distinctly different patterns of early visual field loss using two visual field indices: mean defect and loss variance. Patients were selected on the basis of visual field criteria only. Eight patients were selected for diffuse depression of the differential light sensitivity without localized scotomas (mean defect greater than 3.0 decibels, loss variance less than 10.0 decibels). Seven patients were selected for localized scotomas without diffuse depression of the differential light sensitivity (mean defect less than or equal to 3.0 decibels, loss variance greater than or equal to 20.0 decibels). Patients with diffuse depression manifested intraocular pressures that were higher (mean peak pressure +/- S.E.M., 27.6 +/- 1.2 mm Hg) than those with localized defects (22.4 +/- 1.4 mm Hg). The optic disk rim area of the localized loss group (mean +/- S.E.M., 1.02 +/- 0.15 mm2) was significantly smaller (P less than .05) than the disk rim area of the diffuse loss group (1.33 +/- 0.07 mm2). This difference was largely because of thinner temporal disk rims in the localized loss group. Different patterns of visual field loss may be caused by different mechanisms of glaucomatous optic nerve damage.     

Optic nerve damage in highly myopic eyes with chronic open-angle glaucoma

PURPOSE: To compare the amount of optic nerve damage in relation to intraocular pressure in highly myopic eyes with chronic open-angle glaucoma versus non-highly myopic eyes with chronic open-angle glaucoma. METHODS: The comparative clinical observational study included 1841 eyes of 1100 patients with chronic open-angle glaucoma. The highly myopic study group consisted of 25 eyes with a myopic refractive error equal to or higher than -8 diopters. It was subdivided into eyes with an optic disc size larger than 2.7 mm2 and eyes with an optic disc smaller than 2.7 mm2. The control group included the remaining, non-highly myopic eyes (n=1816). For all patients, a morphometric analysis of color stereo optic disc photographs was performed. Main outcome measures were morphometric optic disc measurements and intraocular pressure. RESULTS: In the highly myopic, large-optic-disc study group compared with the control group, maximal and minimal intraocular pressure readings were significantly (p<0.05) lower and neuroretinal rim area corrected for optic disc size was slightly (p=0.16) smaller. Comparing the total highly myopic study group with a control group adjusted for optic disc area, neuroretinal rim area was significantly (p=0.039) smaller in the study group with no significant difference in intraocular pressure measurements between the groups. CONCLUSIONS: At a given intraocular pressure in chronic open-angle glaucoma, optic nerve damage may be more pronounced in highly myopic eyes with large optic discs than in non-highly myopic eyes. This may suggest a higher susceptibility for glaucomatous optic nerve fiber loss in highly myopic eyes than in non-highly myopic eyes.     

Correlation of the optic disc size to glaucoma susceptibility

Previous studies have suggested that a larger optic disc size in blacks as compared with whites is related to the increased glaucoma susceptibility in blacks. In an intraindividual bilateral comparison of 245 white patients with open-angle glaucoma, the authors evaluated whether the glaucomatous optic nerve damage was greater or less in the eye with the larger optic nerve head. Highly myopic eyes were excluded. The difference in optic disc area of one eye as compared with the contralateral eye was not significantly correlated to the differences in visibility of retinal nerve fiber bundles and mean visual field defect between the two eyes. Mean perimetric loss and the retinal nerve fiber layer index were not significantly higher in the eye with the larger or smaller optic nerve head. This indicates that in whites, high myopes excluded, the susceptibility to glaucomatous optic nerve fiber loss may be independent of the optic disc size.     

Central corneal thickness correlated with glaucoma damage and rate of progression

PURPOSE: To evaluate whether the amount of glaucomatous optic nerve damage at presentation of the patient and the rate of progression of glaucoma during follow-up are related to central corneal thickness. METHODS: The prospective observational clinical study included 861 eyes of 454 white subjects (239 normal eyes of 121 subjects, 250 ocular hypertensive eyes of 118 patients, 372 eyes of 215 patients with chronic open-angle glaucoma). For 567 eyes (304 patients) with ocular hypertension or chronic open-angle glaucoma, follow-up examinations were performed, with a mean follow-up time of 62.7 +/- 33.2 months (median, 60.8; range, 6.2-124.9). All patients underwent qualitative and morphometric evaluation of color stereo optic disc photographs and white-on-white visual field examination. Central corneal thickness was measured by corneal pachymetry. RESULTS: Central corneal thickness correlated significantly (P < 0.001) and positively with the area of the neuroretinal rim and negatively with the loss of visual field. Development or progression of glaucomatous visual field defects detected in 119 (21.0%) eyes was statistically independent of central corneal thickness, in univariate (P = 0.99) and multivariate Cox regression analyses (P = 0.19). CONCLUSIONS: At the time of patient referral, the amount of glaucomatous optic nerve damage correlated significantly with a thin central cornea. Progression of glaucomatous optic nerve neuropathy was independent of central corneal thickness, suggesting that central corneal thickness may not play a major role in the pathogenesis of progressive glaucomatous optic nerve damage.     

Relationship between optic nerve head microcirculation and visual field loss in glaucoma

PURPOSE: To study the relationship between optic nerve head blood flow velocity and visual field loss in patients with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). METHODS: This study included 44 eyes of 44 patients with POAG and 44 eyes of 44 patients with NTG. To evaluate optic nerve head blood flow velocity, the square blur rate (SBR) was measured by means of laser speckle flowgraphy. The correlation between SBR and Humphrey visual field indices was evaluated with linear regression analysis. RESULTS: In the NTG group, the average SBR at the superior and inferior temporal neuroretinal rim was positively correlated with mean deviation (MD) (r = 0.349, p = 0.020). The SBR at the superior or inferior temporal neuroretinal rim was positively correlated with the sum of the total deviations in the corresponding hemifields (r = 0.299, p = 0.049; r = 0.354, p = 0.019, respectively). The correlations between SBR and MD did not differ statistically between the NTG and POAG groups; however, no significant correlation between SBR and visual field indices was observed in the POAG group. CONCLUSION: These results suggested that the change in the circulation of the optic nerve head may be related to visual field damage in the NTG group but may be less involved in visual field damage in the POAG group.