Parapapillary retinal vessel diameter in normal and glaucoma eyes. II. Correlations

The juxtapapillary diameters of the superior temporal and inferior temporal retinal artery and vein have been shown to be significantly smaller in glaucomatous eyes than in normal eyes. They had been measured in 473 eyes of 281 patients with chronic primary open-angle glaucoma and in 275 eyes of 173 normal subjects. In the current study the vessel diameters were correlated with intra- and parapapillary morphometric data and visual field indices. Only one eye per patient and subject was taken for statistical analysis. The retinal vessel calibers were significantly (P less than 0.001) correlated with: (1) the area of the neuroretinal rim as a whole and in four different optic disc sectors; (2) the rim width determined every 30 degrees; (3) the optic cup area and diameters; (4) the horizontal and vertical cup/disc ratios and (5) the quotient of them; (6) the retinal nerve fiber layer score; (7) the area of the parapapillary chorioretinal atrophy; and (8) the visual field indices. In the same eye the vessel caliber was smaller in that sector where the neuroretinal rim loss was highest and the retinal fiber layer score lowest. In intraindividual comparison the vessels were smaller in that eye with less neuroretinal rim tissue and lower nerve fiber layer score. No significant correlations were found with the form of the optic disc, the area of the peripapillary scleral ring, side, sex and refraction. The correlation coefficients were not significantly different when the control group was matched for age. The parapapillary retinal vessel diameter decreases with advancing glaucomatous optic nerve damage. It is correlated with morphometric intra- and parapapillary glaucomatous changes and perimetric defects.     

Parapapillary chorioretinal atrophy in normal and glaucoma eyes. II. Correlations

The parapapillary chorio-pigment-epithelio-retinal atrophy in glaucomatous eyes is significantly larger than in normal eyes. In a previous study its area and frequency have been measured in 582 eyes of 321 patients with chronic primary open-angle glaucoma and in 390 eyes of 231 normal subjects. In the current study the parapapillary changes were correlated with intrapapillary morphometric data and with perimetric indices. The parapapillary chorioretinal atrophy was significantly correlated with the neuroretinal rim area, the horizontal and vertical cup/disc ratios, the quotient of horizontal to vertical cup/disc ratio, the retinal nerve fiber layer score, and the mean visual field loss. It was larger in the same sector where the neuroretinal rim loss was more marked. The correlation coefficients were generally higher for zone "Beta," characterized by complete chorioretinal atrophy with visible large choroidal vessels and sclera, than for zone "Alpha," which showed irregular hypo- and hyperpigmentation. The parapapillary chorioretinal atrophy was correlated in location and time with the intrapapillary glaucomatous changes. It deserves attention in glaucoma diagnosis and follow-up. Its evaluation is especially valuable in eyes with small optic nerveheads (disc size less than 1.6 mm2) in which the intrapapillary glaucomatous changes occur later than the parapapillary ones.     

Small neuroretinal rim and large parapapillary atrophy as predictive factors for progression of glaucomatous optic neuropathy

PURPOSE: To evaluate which morphologic features of the optic disc are predictive factors for progressive neuroretinal rim loss in chronic open-angle glaucoma. DESIGN: Prospective, observational case series. PARTICIPANTS: The study included 394 eyes of 257 white patients with chronic open-angle glaucoma. Mean follow-up time was 31.8 months (median, 39.7 months). Progression of glaucoma was defined as loss of neuroretinal rim as detected by disc photographs. Presence of optic disc hemorrhages was not taken into account. METHODS: All patients underwent repeated qualitative and morphometric evaluation of color stereo optic disc photographs. Statistical analysis included Kaplan-Meier curves, and bivariate and multivariate Cox regression analysis adjusted for patients' ages. Dependency of left and right eyes from the same subject was taken into account. MAIN OUTCOME MEASURES: Qualitative and quantitative morphologic optic nerve head parameters. RESULTS: Progression of glaucomatous optic nerve changes was detected in 42 eyes (11%). At baseline of the study, neuroretinal rim area (total area, P = 0.03) was significantly smaller, and beta zone of parapapillary atrophy (total area, P = 0.04) was significantly larger in the progressive study group compared with the nonprogressive study group. Neither study group varied significantly in size and shape of the optic disc, optic cup depth, alpha zone of parapapillary atrophy, and diameter of the retinal arteries and veins (P > 0.05). Multiple Cox regression analysis revealed that the progression of glaucoma depended significantly on the area of the neuroretinal rim (temporal sector, P = 0.003) and beta zone of parapapillary atrophy (temporal inferior sector, P = 0.02). CONCLUSIONS: Important morphologic predictive factors for progression of the glaucomatous appearance of the optic nerve head in white persons are small size of neuroretinal rim and large area of beta zone of parapapillary atrophy. Progression of glaucomatous optic nerve head changes is independent of size and shape of the optic disc, size of alpha zone of parapapillary atrophy, retinal vessel diameter, and optic cup depth.     

Parapapillary region in normal and glaucoma eyes. II. Correlation of planimetric findings to intrapapillary, perimetry and general data

The planimetric values of the parapapillary region in 312 unselected eyes with chronic primary open-angle glaucoma and 125 normal eyes of an age-/and refraction-matched control group were correlated to the intrapapillary, perimetric, and general data of these eyes. High myopics (less than -8.00 D) and "ocular hypertensives" were excluded. Zone "Alpha" and "Beta" incipient to advanced or subtotal to total parapapillary chorio-pigmentepithelioretinal atrophy) were significantly correlated (p less than 0.001) to: 1) area and width of the neuroretinal rim as a whole and in four different optic disk sectors; 2) cup area; 3) horizontal and vertical c/d ratios; 4) glaucoma stage; 5) age, and 6) refraction. Zone "Beta" was additionally correlated to the perimetric indices. Its correlation coefficients were generally higher than those of zone "Alpha." Sex and side showed no significant relationships. Divided into four different radial sectors, both zones "Alpha" and "Beta" were significantly larger (p less than 0.001) the smaller the neuroretinal rim area (intrapapillary) in the same sector was. Additionally, zone "Beta" was significantly (p less than 0.001) most often largest in the sector where the rim area was smallest. Thus, besides the temporal there was also a spatial correlation between the intrapapillary and parapapillary glaucomatous alterations. "Conus pigmentosus" and the peripapillary scleral rim showed no significant glaucoma-associated correlations and are thus without importance for quantified optic disk evaluation in glaucoma. Zones "Alpha" and "Beta", as regions of early to advanced of subtotal to total parapapillary, chorio-pigmentepithelioretinal atrophy, are not only chronologically but also spatially correlated to intrapapillary glaucomatous changes and are important in optic disk evaluation in glaucoma.     

Ranking of optic disc variables for detection of glaucomatous optic nerve damage

PURPOSE: To describe optic disc variables assessed by evaluation of clinical optic disc photographs and to compare sensitivity and specificity of these optic disc parameters in identifying patients with ocular hypertension who have nerve fiber layer defects and normal visual fields and patients with visual field defects. METHODS: The study included 500 normal subjects, 132 patients with ocular hypertension with retinal nerve fiber layer defects and normal visual fields (preperimetric glaucoma), and 840 patients with glaucomatous visual field defects. Color stereo optic disc photographs were morphometrically evaluated. RESULTS: Highest diagnostic power for the separation between the normal group and the preperimetric glaucoma group had the vertical cup-to-disc diameter ratio corrected for its dependence on the optic disc size, total neuroretinal rim area, rim-to-disc area ratio corrected for disc size, and cup-to-disc area ratio corrected for disc size. Diagnostic power was lower for rim area in the temporal inferior and temporal superior disc sector, cup area corrected for disc size, and horizontal cup-to-disc diameter ratio corrected for disc size. Less useful for the differentiation between the normal subjects and the preperimetric glaucoma group were size of zones alpha and beta of parapapillary chorioretinal atrophy, and ratios of neuroretinal rim width and rim area comparing various optic disc sectors with each other. CONCLUSIONS: In subjects with ocular hypertension with retinal nerve fiber layer defects and normal conventional achromatic visual fields, the vertical cup-to-disc diameter ratio corrected for optic disc size, total neuroretinal rim area, rim-to-disc area ratio, and cup-to-disc area ratio corrected for disc size are the most valuable optic disc variables for early detection of glaucomatous optic nerve damage. Correction for optic disc size is necessary for optic disc variables directly or indirectly derived from the optic cup. Parapapillary atrophy is less important in the early detection of glaucoma.     

Advances in the assessment of optic disc changes in early glaucoma

Looking for early glaucomatous changes in the morphology of the optic disc and retinal nerve fiber layer, ocular hypertensive subjects should be checked to determine 1) whether the neuroretinal rim has its characteristic physiologic form with its largest parts in the inferior and superior disc regions and its smaller part in the temporal disc sector; 2) whether zone beta of the parapapillary chorioretinal atrophy is present or whether zone alpha is abnormally large; 3) whether the visibility of the retinal nerve fiber layer is diffusely reduced; and 4) whether localized defects of the retinal nerve fiber layer can be detected. Usually not occurring in normal eyes, an optic disc hemorrhage also indicates abnormality. These variables can be evaluated in every routine ophthalmoscopic examination, or by applying sophisticated techniques such as the scanning laser tomography and measurement of the height and contour of the parapapillary retinal nerve fiber layer.     

Optic disc morphology after arteritic anterior ischemic optic neuropathy

OBJECTIVE: To evaluate the appearance of the nerve head in patients after giant cell arteritis-induced arteritic anterior ischemic optic neuropathy (A-AION). DESIGN: Noncomparative clinical case series. PATIENTS: The study comprised 29 patients who presented with unilateral A-AION and temporal artery biopsy-proven giant cell arteritis. Stereoscopic optic disc photographs, taken of both the affected and unaffected eyes at the onset of the disease and after a follow-up period of 20.10 +/- 25.36 months (median, 11 months; range, 2-102 months), were morphometrically evaluated. MAIN OUTCOME MEASURES: Size and shape of the optic disc, neuroretinal rim, optic cup, and alpha and beta zones of parapapillary atrophy. RESULTS: In the eyes after A-AION, at the end of the study, the neuroretinal rim was significantly (P = 0.002) smaller, and the optic disc cup area was significantly (P = 0.001) larger than those of the contralateral unaffected eyes. Alpha zone and beta zone of parapapillary atrophy did not vary significantly (P > 0.50). CONCLUSIONS: A-AION, like glaucomatous optic neuropathy, results in neuroretinal rim loss and optic disc cupping. However, in contrast to glaucoma, A-AION is not associated with an enlargement of parapapillary atrophy. The reasons and mechanisms responsible for these similarities and dissimilarities are discussed. Marked clinical, morphologic, and histopathologic similarities in optic disc cupping and loss of neuroretinal rim between A-AION and glaucomatous optic neuropathy are highly suggestive of a common mechanism for the development of the two diseases (i.e., ischemia of the optic nerve head). The subject is discussed at length.     

Optic disk morphology in experimental central retinal artery occlusion in rhesus monkeys.

PURPOSE: To evaluate longitudinally the optic disk morphology of nonglaucomatous optic nerve damage secondary to retinal nerve fiber damage, using experimental central retinal artery occlusion in rhesus monkey eyes as a model. METHODS: This prospective study included 24 eyes of 16 monkeys. In eight eyes of eight animals, central retinal artery occlusion was produced by clamping the central retinal artery in the retrobulbar space. Occlusion was verified by fluorescein fundus angiography. The same eyes at baseline as well as the eight contralateral healthy eyes and eight monkey eyes with experimental high-pressure glaucoma served as control groups. Serially taken optic disk photographs were morphometrically evaluated. RESULTS: The area and shape of the neuroretinal rim and alpha zone and beta zone of parapapillary chorioretinal atrophy of eyes after central retinal artery occlusion did not vary significantly (P > .30) from the same eyes before central retinal artery occlusion nor from the normal contralateral eyes. In the glaucomatous eyes, the neuroretinal rim was significantly (P < .001) smaller and parapapillary atrophy significantly (P = .01) larger than in the eyes after central retinal artery occlusion. CONCLUSIONS: Experimental central retinal artery occlusion, in contrast to glaucoma, does not markedly change the size and shape of parapapillary atrophy and neuroretinal rim; this confirms previous clinical studies. Thus, assessment of parapapillary atrophy and neuroretinal rim may be helpful to differentiate between glaucomatous optic neuropathy and nonglaucomatous optic neuropathy secondary to retinal nerve fiber damage. Parapapillary atrophy is independent of decreased retinal blood perfusion and development of nonglaucomatous optic nerve atrophy following experimental central retinal artery occlusion.     

Optic disc morphometry in simple optic nerve atrophy

This study was undertaken to evaluate the optic disc changes in eyes with non-glaucomatous optic nerve damage. The intra- and parapapillary region was evaluated morphometrically in 106 eyes of 56 patients with simple optic nerve atrophy (SONA) and in 107 normal eyes of 57 subjects. Colour stereo optic disc diapositives were used. Only one randomly chosen eye per subject and patient was taken for statistical analysis. Characteristics of SONA were: decreased visibility of the parapapillary retinal nerve fibers, diminished retinal vessel diameter, and area with pallor larger than area with cupping. Size and form of the optic disc, neuroretinal rim, peripapillary scleral ring, and zone Alpha and Beta of the parapillary chorioretinal atrophy were not significantly different. Also, distinctness of a tesselated fundus, frequency of optic disc haemorrhages and frequency of bared circumlinear or bared cilioretinal vessels did not differ significantly. These morphologic features are helpful in the diagnosis and differential diagnosis of SONA.     

Study of the optic papilla and nerve fiber layer in glaucoma]

BACKGROUND: For diagnosis and follow-up of glaucoma an exact evaluation of the optic nerve disc and the nerve fiber layer is necessary. METHODS: The slit-lamp evaluation of the optic nerve disc and nerve fiber layer is presented as well as the evaluation with the Nerve Fiber Analyzer and the Heidelberg Retina Tomograph. RESULTS: Signs of a glaucomatous optic disc include a difference of more than 0.2 in the vertical cup to disc (CD) ratio between the eyes, a vertical CD ratio exceeding more than 0.1 the horizontal, larger CD ratios in small optic discs, notching of the neuroretinal rim, an enlarged zone beta of parapapillary chorioretinal atrophy, and peripapillary hemorrhages. Atrophy of the nerve fiber layer may be localized or diffuse. Both types of atrophy may be present at the same time. CONCLUSIONS: Knowledge of all signs of the glaucomatous optic disc and forms of nerve fiber layer atrophy allows an earlier diagnosis of glaucoma and an earlier recognition of progression.     

Monitoring of morphometric changes of optic discs with morphologic progression of glaucomatous optic atrophy by means of laser scanner tomography

AIM: Aim of this study was to measure morphometric changes in optic discs with laser-scanning tomography (HRT, Heidelberg-Retina-Tomograph, Heidelberg) in eyes with early glaucomatous morphologic progression. PATIENTS AND METHODS: 61 eyes of 36 patients with marked neuroretinal rim loss or its early morphologic signs (1. optic disc hemorrhages, 2. reduced visibility of the retinal nerve fiber layer (RNF), 3. appearance of narrowing of retinal vessels, 4. enlargement of the choroidal, parapapillary atrophy) were compared to 74 normal eyes of 39 probands. 15 degrees stereographs of the optic discs were evaluated for morphologic changes. The morphometric variables of the neuroretinal rim and excavation measured by the HRT were examined in the course of the disease. RESULTS: In the group of normals no significant changes of the neuroretinal rim in the course of 2.0 +/- 1.2 years were found. In the group of glaucomatous eyes (3.0 +/- 1.5 years follow-up) 34 eyes showed marked neuroretinal rim loss, 17 disc hemorrhages, 4 vessel narrowing, 3 an increased chorioidal atrophy, 3 a decreased visibility of the retinal nerve fiber layer. In these eyes a significant loss of rim area (p = 0.01) and an increase of excavation area (p = 0.0001) and volume (p = 0.003) was measured by the HRT. Only three eyes showed a perimetric loss of sensitivity (0.8-3.4 db) in Octopus static perimetry. CONCLUSIONS: Laser-scanning tomography of the optic disc seems to be able to measure morphometric changes in eyes with morphologic progression of glaucomatous optic atrophy, even before perimetric changes occur.     

Five rules to evaluate the optic disc and retinal nerve fiber layer for glaucoma.

A systematic approach for the examination of the optic disc and retinal nerve fiber layer is described that will aid in the detection of glaucoma. This approach encompasses 5 rules: evaluation of optic disc size, neuroretinal rim size and shape, retinal nerve fiber layer, presence of parapapillary atrophy, and presence of retinal or optic disc hemorrhages. A systematic process enhances the ability to detect glaucomatous damage as well as the detection of progression, and facilitates appropriate management.     

Optic nerve head appearance in juvenile-onset chronic high-pressure glaucoma and normal-pressure glaucoma

OBJECTIVE: To evaluate the appearance of the optic nerve head in chronic high-pressure glaucoma and normal-pressure glaucoma. DESIGN: Clinic-based cross-sectional study. PARTICIPANTS: The study included 52 eyes with normal-pressure glaucoma and 28 eyes with juvenile-onset primary open-angle glaucoma that served as models for chronic high-pressure glaucoma. METHODS: Color stereo optic disc photographs and wide-angle retinal nerve fiber layer photographs were morphometrically examined. MAIN OUTCOME MEASURES: Localized retinal nerve fiber layer defects; parapapillary chorioretinal atrophy; disc hemorrhages; optic cup shape; retinal arteriole narrowing. RESULTS: Both study groups did not vary significantly in count of localized retinal nerve fiber layer defects, size of parapapillary atrophy, optic cup depth, steepness of disc cupping, rim/disc area ratio, diameter of retinal arterioles, and frequency and degree of focal retinal arteriole narrowing. In normal-pressure glaucoma versus juvenile open-angle glaucoma, localized retinal nerve fiber layer defects were significantly broader, disc hemorrhages were found significantly more often and were larger, and neuroretinal rim notches were present more frequently and were deeper. CONCLUSIONS: Chronic high-pressure glaucoma and normal-pressure glaucoma show morphologic similarities in the appearance of the optic nerve head. The lower frequencies of detected disc hemorrhages and rim notches in high-pressure glaucoma may be due to a smaller size of hemorrhages and localized retinal nerve fiber layer defects in high-pressure glaucoma. Both glaucoma types have morphologic features in common, suggesting that they may possibly belong to a spectrum of the same pathologic process.     

Parapapillary retinal vessel caliber. II. Caliber reduction in eyes with glaucoma (a papillometric study of 309 eyes with chronic simple glaucoma compared with 264 normal eyes)

The diameter of the temporal superior or inferior artery and vein was measured at the optic disk border and 2 mm from the disk center in 309 nonselected eyes with chronic primary open-angle glaucoma. The values obtained were compared with those of 264 nonselected normal eyes. The calibers of both vessels were significantly larger in the normal eyes than in the glaucomatous ones (p = 0.000 or p less than 0.01; Wilcoxon-Mann-Whitney test). Their diameters diminished significantly (p less than 0.001) with decreasing width and area of the neuroretinal rim as a whole and when divided into different optic disk sectors, and with increasing optic cup area, horizontal and vertical cup/disk ratios, area of the subtotal to total parapapillary choriopigmentepithelioretinal atrophy, perimetric loss, and glaucoma stage. Thus, the caliber of the parapapillary retinal vessels decreases significantly with increasing glaucomatous optic nerve damage.     

Morphologic predictive factors for development of optic disc hemorrhages in glaucoma

PURPOSE: To evaluate which optic disc parameters are predictive factors for the development of disc hemorrhages in chronic open-angle glaucoma. METHODS: The prospective comparative clinical observational study included 432 eyes of 281 white patients with chronic open-angle glaucoma. Mean follow-up time was 38.8 months (median, 31.5). Eyes in the whole study group were divided into those with an optic disc hemorrhage during the follow-up period (hemorrhagic group; n = 38; 8.8%), those without disc hemorrhages and with neuroretinal rim loss as sign of progression of glaucoma (rim loss group; n = 42; 9.7%), and those with neither disc hemorrhages nor neuroretinal rim loss (stable group; n = 352; 81.5%). Color stereo optic disc photographs were obtained repeatedly in all patients and subjected to qualitative and morphometric evaluation. RESULTS: At baseline, neuroretinal rim area was significantly (P < 0.03) smaller and the beta zone of parapapillary atrophy (temporal lower sector) was significantly (P < 0.03) larger in the hemorrhagic group than in the stable group. Both study groups did not vary significantly (P > 0.05) in optic disc size and shape, optic cup depth, alpha zone of parapapillary atrophy, and retinal vessel diameter. In multivariate analysis, the neuroretinal rim area was the only significant predictor of hemorrhages. The hemorrhagic group and the rim loss group did not differ significantly (P > 0.05) in any optic disc parameter measured. CONCLUSIONS: In chronic open-angle glaucoma, morphologic predictive factors for the development of disc hemorrhages are small size of neuroretinal rim and, possibly, a large parapapillary beta zone. Development of disc hemorrhages is independent of optic disc size and shape, size of alpha zone of parapapillary atrophy, retinal vessel diameter, and optic cup depth. Optic nerve heads in eyes with eventual development of disc hemorrhages and in eyes with eventual progressive rim loss without observed disc hemorrhages do not differ markedly in appearance.     

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.     

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.     

Ophthalmoscopic appearance of the normal optic nerve head in rhesus monkeys

PURPOSE: To evaluate the ophthalmoscopic appearance of the normal optic disc, parapapillary region, and retinal nerve fiber layer in rhesus monkeys. METHODS: Color stereo fundus photographs of 17 normal eyes of 17 rhesus monkeys aged between 13 and 23 years were morphometrically evaluated. RESULTS: The neuroretinal rim was significantly (P: < 0.008) broadest in the inferior disc region followed by the superior disc region, the nasal region, and the temporal region. Retinal nerve fiber layer visibility was significantly highest in the inferior temporal fundus region followed by the superior temporal fundus region, the superior nasal fundus region, and the inferior nasal fundus region. It decreased significantly (P: < 0.001) with increasing age. The retinal arterioles were significantly (P: < 0.01) wider in the inferior temporal and superior temporal fundus regions than in the superior nasal and inferior nasal fundus regions. The alpha zone of parapapillary atrophy (14/17 or 82.4%) occurred significantly (P: < 0.001) more often than the beta zone (2/17 or 11.8%). In 15 eyes (88. 2%), the foveola was located inferior to a horizontal line drawn through the center of the optic disc. Neuroretinal rim shape and area and size of alpha and beta zones of parapapillary atrophy were independent of age. CONCLUSIONS: As in humans, in normal rhesus monkeys the neuroretinal rim has a typical physiologic configuration that spatially correlates with the retinal arteriole diameter, retinal nerve fiber layer visibility, and position of the foveola inferior to the center of the optic disc. Neuroretinal rim shape is independent of age. Retinal nerve fiber layer visibility decreases significantly with increasing age. These findings may be useful for the early detection and differentiation of experimental optic nerve damage in rhesus monkeys.     

Central retinal vessel trunk exit and location of glaucomatous parapapillary atrophy in glaucoma

OBJECTIVE: To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma. DESIGN: Clinic-based, observational, cross-sectional study. PATIENTS: Color stereo optic disc photographs of 95 patients with primary or secondary open-angle glaucoma and 65 healthy persons were morphometrically evaluated. The intrapapillary and parapapillary region was divided into four quadrants. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy and neuroretinal rim in the four quadrants. MAIN OUTCOME MEASURES: The area of neuroretinal rim and parapapillary atrophy and the position of the central retinal vessel trunk exit. RESULTS: Comparing measurements between opposite disc quadrants showed that beta zone of parapapillary atrophy was significantly (P < 0.05) larger and that the neuroretinal rim was significantly smaller when beta zone and neuroretinal rim were measured in the disc quadrant most distant to the central retinal vessel trunk exit, than if the beta zone and neuroretinal rim were measured in the quadrant containing the vessel trunk exit. Comparing measurements in the disc quadrants between eyes with different positions of the central retinal vessel trunk exit revealed that, in the respective disc quadrant, the beta zone was significantly larger and the neuroretinal rim was smaller in eyes with the vessel trunk exiting in the opposite disc quadrant than in eyes with the vessel trunk exit located in the respective disc quadrant where the measurements were obtained. CONCLUSIONS: Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy and the smaller is the neuroretinal rim. This relationship agrees with the spatial relationship between glaucomatous neuroretinal rim loss and enlarged parapapillary atrophy in glaucoma. Diagnostically, it may indicate that, in eyes with an abnormal configuration of parapapillary atrophy or with an abnormal position of the central retinal vessel trunk exit, early glaucomatous rim changes should be looked for in the disc sector that is most distant to the central retinal vessel trunk exit and where parapapillary atrophy may be relatively large.