Radiation therapy of optico-hypothalamic gliomas (OHG)--radiographic response, vision and late toxicity.

BACKGROUND: Management strategies for optic pathway gliomas include observation, surgery, irradiation, chemotherapy and a combination of these modalities. It has been the policy of our University Hospital to consider radiation as the standard treatment for progressive optic pathway gliomas. This report describes the clinical presentation, treatment patterns and outcome with special emphasis on the long term functional status of patients with optico-hypothalamic gliomas (OHG). PATIENTS AND METHODS: Between 1975 and 1997, 25 patients with OHG were treated by radiation therapy (RT) following surgery or biopsy. All patients received a local RT with a 0.5-1 cm margin around the lesions as depicted on CT or MRI scans. Age adjusted radiation doses ranged from 45 to 60 Gy with a single fraction size of 1.6-2 Gy. Endpoints of the study were: radiographic response, survival, progression-free survival and time to endocrinologic toxicity as well as the visual function during follow-up. The median follow-up time was 9 years (range, 1.5-23 years). RESULTS: A partial response was noted in six (24%) of the patients, 13 (52%) patients had a stable tumour throughout the observation period and six (24%) patients had a tumour progression. Overall survival and progression-free survival rates were 94 and 69% at 10 years, respectively. A significant influence on progression-free survival was noted for age at diagnosis (P=0.04) and total dose (P=0.05). Nine out of 13 (69%) patients aged below 10 years compared with 3/12 (25%) patients aged above 10 years experienced hypothalamic-pituitary deficiency (P=0.008) during follow-up. As for visual acuity, nine patients had an improvement, another 13 patients a stable situation and three patients a measurable deterioration. Visual field deficits improved in three, remained unchanged in 16 patients and worsened in only one patient. CONCLUSION: Postoperative RT with a total dose above 45 Gy should be considered as standard treatment in OHG with documented progression. Close radiographic monitoring and lifelong yearly evaluation for the need of possible hormone replacement are strongly recommended.

[Optical sector iridectomy: an alternative to perforating keratoplasty in Peters' anomaly]. / Optische Sektoriridektomie: Eine Alternative zur perforierenden Keratoplastik bei Petersscher Anomalie.

BACKGROUND: The penetrating keratoplasty as an early surgical procedure to present deep irreversible amblyopia in patients suffering from Peters' anomaly has shown an extremely high risk for transplantat failure. PATIENTS AND METHODS: From 1980 to 1992 20 sectoriridectomies (6 bilateral, 1 twice because of progressive corneal opacification in the area of sectoriridectomy) were performed in 13 patients with Peters' anomaly (diameter of corneal opacification greater than half of the corneal diameter). The mean age at surgery was 1 year and 9 months, the mean follow-up was 3 years and 6 months. Preoperatively the visual function was uncertain light perception in all eyes with marked horizontal nystagm. Except for two eyes (24 mm Hg) the intraocular pressure (IOP) was normal. RESULTS: In 9 (47%) eyes the visual acuity was 20/500 to 20/200. One eye showed certain light fixation, one eye hand movement. In one eye the visual function remained uncertain light perception "after combined lens aspiration." One eye developed a phthisis after combined anterior vitrectomy and lens aspiration for PHPV. In three eyes, the visual outcome could not be determined certainly, in three eyes, the follow-up failed. In two eyes the IOP was regulated under topical antiglaucomatous eye drops, in the other eyes the IOP was normal. CONCLUSIONS: In contrast to penetrating keratoplasty sectoriridectomy seems not to be followed by secondary glaucoma postoperatively. The visual outcome is comparable to that after early keratoplasty. We recommend "optical" sectoriridectomy as an alternative surgical approach to early penetrating keratoplasty in patients suffering from Peters' anomaly.

[Sensitivity of refraction measurement with the infrared videorefractometer VRB 200]. / Sensitivität der Refraktionsmessung mit dem Infrarot-Videorefraktometer VRB 200.

AIM OF THE STUDY: This study investigates the sensitivity of a computerised videorefractor (VRB 200) for refractive errors, especially amblyopiogenic, in babies and infants. PATIENTS AND METHODS: Videopictures from 312 eyes of 156 babies and infants were taken, evaluated and compared with the current measurements (skiaskopy or refractometry) of the university eye hospital Erlangen-Nürnberg. RESULTS: 255 (81.7%) of 312 eyes were evaluable. The VRB 200 achieves a sensitivity of 96.1% in hyperopic eyes (219 of 228 eyes) and 94.7% in myopic eyes respectively (18 of 19 eyes). Of 8 emmetropic eyes 6 were recognized correctly negative. Astigmatism could be estimated coarsely quantitatively in power and qualitativ in the axis with a sensitivity of 80% (92 of 115 eyes) and a specificity of 86% (121 of 140). Anisometropia over 2 dpt was recognized in 5 of 6 patients. A general statement concerning the specificity is not possible with this study, because it is not a mass screening procedure. CONCLUSION: This videorefractor is able to recognize semi-quantitatively ambylopiogenic refractive errors with high sensitivity.

[Ocular motility disorder as a primary symptom of temporal arteritis]. / Augenbewegungsstörung als Primärsymptom einer Arteriitis temporalis.

UNLABELLED: HISTORY AND METHODS: Six weeks after onset of a monocular elevation paresis of the left eye a 78-year-old man presented with an anterior ischemic optic neuropathy of the right eye. This time a monocular elevation paresis was observed in the right eye. The diagnosis of arteritis temporalis was confirmed histologically. THERAPY AND CLINICAL COURSE: Systemic steroid therapy was administered. Five days later the patient developed signs of an acute vertebrobasilar insufficiency. After further steroid therapy the neurologic signs and the motility disorder resolved. The visual acuity of the right eye improved from 1/20 to 6/20, but the visual field remained poor. CONCLUSION: In retrospect the monocular elevation paresis was the initial sign of the temporal arteritis. The combination of the affected muscles and the change of the affected eye were hints at a prenuclear origin of the paresis. General signs of an acute vertebrobasilar ischemia supported this supposed localisation.

[Congenital nystagmus and intermittent exotropia. Suppression of nystagmus by fusional convergence]. / Kongenitaler Nystagmus und intermittierende Exotropie. Nystagmushemmung durch fusionale Konvergenz.

We report on a patient with a combination of congenital nystagmus and intermittent exotropia. When the exotropia became manifest, a gross nystagmus appeared. When, however, the exotropia was overcome by fusinal convergence, the nystagmus was largely suppressed. The angle of squint was surgically reduced by such an amount that the exodeviation was just compensated, and the fusional convergence required to overcome the remaining angle sufficed to suppress the nystagmus.

Correlation of the blind spot size to the area of the optic disk and parapapillary atrophy.

We evaluated the relationship between the optic disk and the blind spot area. Using kinetic Goldmann perimetry in 23 patients with open-angle glaucoma and 19 normal subjects, the blind spot size was correlated significantly with the total area of the optic disk, peripapillary scleral ring, and parapapillary chorioretinal atrophy. Zone beta of the parapapillary atrophy with a visible sclera was attributed to an absolute scotoma, and zone alpha with irregular pigmentation was attributed to a relative scotoma. The blind spot was significantly larger in the glaucomatous eyes than in the normal eyes, which corresponded with a larger zone beta in the glaucomatous eyes. The intrapapillary and parapapillary region of the optic nerve head correlated to the size of the blind spot, which included the parapapillary chorioretinal atrophy and a significant size difference between normal and glaucomatous eyes.

[Retinal vascular occlusions are independent of optic disk size. A morphometric study of 140 patients]. / Retinale Gefässverschlüsse sind unabhängig von der Papillengrösse. Eine morphometrische Untersuchung von 140 Patienten.

The size of the optic nerve head influences the prevalence of optic disk anomalies and diseases. The authors investigated whether this also holds true for retinal vessel occlusions. The optic disks of 140 patients with central or branch occlusions of the retinal veins and arteries were measured, using photographs of the optic disk and correcting the photographic enlargement by Littmann's method. There were no significant differences in size and shape (Mann-Whitney Test) between the disks thus studied and 457 nonselected optic nerve heads. The incidence of retinal vessel occlusions appears to be unrelated to the shape and size of the optic disk.

Parapapillary chorioretinal atrophy in normal and glaucoma eyes. I. Morphometric data.

Glaucomatous optic nerve damage is associated with alterations of the intra- and parapapillary optic disc area. We measured and compared the parapapillary region in 582 eyes of 321 patients suffering from chronic primary open-angle glaucoma and in 390 eyes of 231 normal subjects. Only one randomly assessed eye per patient and subject was taken for statistical analysis. Highly mopic eyes with a myopic refractive error of more than -8.00 diopters had been excluded. The parapapillary chorioretinal atrophy was divided into a peripheral zone "Alpha" with irregular hyper- and hypopigmentation, and a more central zone "Beta" characterized by whitish colour, visible large choroidal vessels and visible sclera. In the normal eyes both zones were significantly (P less than 0.001) largest and most common in the temporal horizontal sector, followed by the inferior temporal sector, the superior temporal sector and finally the nasal sector. In the glaucoma group both zones were significantly larger (P less than 0.0001; Mann-Whitney test) and more frequent than in the normal eyes (0.40 +/- 0.32 mm2 versus 0.65 +/- 0.49 mm2 for zone Alpha, 0.13 +/- 0.42 mm2 versus 0.79 +/- 1.17 mm2 for zone Beta). The differences were significant also for the earliest glaucoma stage of this study. They were most marked for the nasal parapapillary sector. Significant differences (P less than 0.001) between the normal group and the earliest glaucoma stage were: zone Alpha larger than 0.20 mm2 or broader than 0.20 mm in the temporal horizontal sector, total area of zone Alpha larger than 0.30 mm2, occurrence of zone Alpha in the nasal sector, and occurrence of zone Beta anywhere.

Pseudoglaucomatous physiologic large cups.

Using planimetric analysis of stereoscopic optic disk photographs, we studied 21 optic nerve heads of 11 subjects who shared the common feature of optic cups that were larger than the mean + 2 S.D. within the normal population. A comparison of these findings to those of 571 normal optic disks and 706 optic nerve heads in eyes with chronic primary open-angle glaucoma showed the following morphologic characteristics: (1) abnormally large optic disk area (mean +/- S.D., 4.49 +/- 0.56 mm2), (2) large cup/disk ratios with the horizontal ratio (0.78 +/- 0.03) significantly (P less than .001) larger that the vertical (0.71 +/- 0.03), (3) increased incidence of cilioretinal arteries, (4) normal neuroretinal rim area (2.06 +/- 0.35 mm2), (5) normal neuroretinal rim configuration, inferiorly (0.43 +/- 0.08 mm) broader (P less than .001, Wilcoxon test) than superiorly (0.33 +/- 0.06 mm), smallest (P less than .0001) temporally (0.20 +/- 0.04 mm), (6) normal form of zone alpha (irregular hypopigmentation and hyperpigmentation) of the parapapillary chorioretinal atrophy with its widest extension in the temporal horizontal area, (7) no zone beta (visible large choroidal vessels and sclera), (8) normal caliber of the parapapillary retinal vessels, and (9) normal parapillary retinal nerve fiber layer. These characteristics are helpful in the differentiation of primary and secondary large cups.

[Correlation of intra- and para-papillary glaucomatous changes--a planimetric study of 200 normal and 450 glaucoma eyes]. / Korrelationen zwischen den intra- und parapapillären glaukomatösen Veränderungen--eine planimetrische Studie über 200 Normal-und 450 Glaukomaugen.

The zone "alpha" (irregular hypo- und hyperpigmentation) and "beta" (visible large choroidal vessels and visible sclera) of parapapillary chorioretinal atrophy had been measured in 450 eyes of 330 patients suffering from chronic primary open-angle glaucoma and in 200 normal eyes of 161 subjects. In the present study, the results were correlated with intrapapillary and other parapapillary parameters. Significant correlations (p less than 0.001) were found with: (1) the neuroretinal rim size; (2) the horizontal and vertical cup/disc ratios and the quotient; (3) the frequency of bared circumlinear and cilioretinal vessels and of optic disc hemorrhages, respectively; (4) the retinal vessel diameter; (5) the visibility of the retinal nerve fiber bundles; (6) the glaucoma stage. The parapapillary changes were most marked in the sector in which the neuroretinal rim notch was the largest and the narrowness of the retinal vessel caliber the most pronounced. The parapapillary glaucomatous changes in time and location correlated with the intrapapillary and other parapapillary alterations. They deserve special attention in the diagnosis of glaucoma.

[Planimetry of glaucomatous, para-papillary, chorio-pigment epithelial retinal atrophy]. / Planimetrie der glaukomatösen, parapapillären, chorio-pigmentepithelio-retinalen Atrophie.

Glaucomatous optic nerve damage is associated with changes in the parapapillary region. These changes were measured on 15 degrees color stereo slides of the optic nerve head. We examined 450 eyes of 330 patients suffering from chronic primary open-angle glaucoma and 200 eyes of 161 normal subjects. The glaucoma group was divided into five stages according to the neuroretinal rim configuration. In the parapapillary region, the "alpha" zone characterized by irregular hypo- and hyperpigmentation, and the "beta" zone (large visible choroidal vessels and visible sclera) were differentiated. Zone "beta" was located between the optic disc and zone "alpha". Both zones were significantly larger in the total glaucoma group (p less than 0.00001, Mann-Whitney-test), and in each of the five glaucoma stages, than in the normal subjects. Zone "beta" increased in size more than zone "alpha". The parapapillary region deserves special attention in the diagnosis of glaucoma.

[Qualitative morphologic characteristics of normal and glaucomatous optic papillae]. / Qualitative morphologische Charakteristika von Normal- und Glaukompapillen.

Using optic disk photographs, qualitative morphologic characteristics of the optic nerve head were determined in 251 nonselected normal eyes and 308 eyes with chronic primary open-angle glaucoma. These characteristics were correlated to morphometric (both intra- and parapapillary) and perimetric data. The highest degree of accuracy in distinguishing normal from glaucomatous optic disks was found with the characteristics "localization of narrowest point of neuroretinal rim outside the temporal horizontal optic disk sector" (85.5%) and "changes in the parapapillary retinal nerve fiber layer" (87.9%). The signs "baring of circumlinear vessels," "baring of cilioretinal arteries," "epipapillary flame-shaped hemorrhages," and "bridging of the vessel trunk" were highly specific for glaucomatous optic nerve damage (94.4%-100%) and less sensitive (5.8%-25.3%). Bayonetlike vessel kinking," "prevalence of cupping nasal to the main vessel trunk," "baring of the lamina cribrosa pores," and "undermining of the cup border" were less useful in qualitative evaluation of the optic disk. The location of the central artery in relation to the central vein (nasal in 98.4%), prevalence of the cilioretinal arteries, and the total number of circumlinear vessels were not significantly correlated to changes associated with glaucoma and are therefore of no importance for optic disk evaluation in glaucoma.

Optic disc, cup and neuroretinal rim size, configuration and correlations in normal eyes.

Four hundred and fifty-seven unselected normal human optic nerve heads of 319 subjects (163 men, 156 women, mean age 42.7 +/- 19.6 years) were evaluated by magnification-corrected morphometry of optic disc photographs. Mean optic disc surface measured 2.69 +/- 0.70 mm2 (0.80-5.54 mm2), mean diameter horizontally 1.76 +/- 0.31 mm (0.91-2.61 mm), and vertically 1.92 +/- 0.29 mm (0.96-2.91 mm). The form was slightly vertically oval. Optic cup area averaged 0.72 +/- 0.70 (0.00-3.41 mm2), mean horizontal cup diameter 0.83 +/- 0.58 mm (0.00-2.08 mm) and mean vertical diameter 0.77 +/- 0.55 mm (0.00-2.13 mm). The cup was significantly (P less than 0.0001) larger in discs with steep "punched-out" cups (1.37 +/- 0.62 mm2) compared to discs having cups with temporal flat slopes (0.59 +/- 0.39 mm2). Neuroretinal rim area ranged from 0.80 to 4.66 mm2 (mean 1.97 +/- 0.50 mm2), and was significantly correlated (P less than 0.00001) to the optic disc area. It was broadest in the inferior optic disc region (P less than 0.001), followed by the superior, nasal and temporal (P less than 0.001) regions. Horizontal cup/disc ratio (mean 0.39 +/- 0.28, minimum 0.00, maximum 0.87) was larger in 426 (93.2%) optic discs than the vertical one (mean 0.34 +/- 0.25, minimum 0.00, maximum 0.85). Concerning optic disc area, side differences of 0.10 mm2 or less were detected in 28%, of 0.2 mm2 or less in 46% and of 0.50 mm2 or less in 80% (cumulative frequencies). Concerning neuroretinal rim area, side differences of 0.10 mm2 or less were found in 31%, of 0.20 mm2 or less in 52% and of 0.50 mm2 or less in 84%.(ABSTRACT TRUNCATED AT 250 WORDS)

[The parapapillary region of normal and glaucoma eyes. I. Planimetric values of 312 glaucoma and 125 normal eyes]. / Die parapapilläre Region in Normal- und Glaukomaugen. I. Planimetrische Werte von 312 Glaukom- und 125 Normalaugen.

Magnification-corrected planimetry of the parapapillary region was performed according to Littmann's method in 312 unselected eyes with chronic primary open-angle glaucoma and in 125 normal eyes of an age- and refraction-matched control group using optic disk photographs. The glaucoma group was divided into five pathomorphologic subgroups. High myopics (less than -8.00 D) and "ocular hypertensives" had been excluded. The coefficient of variation ranged intraindividually from 0.0 to 0.17 and interindividually from 0.0 to 0.16. Two different morphologic variants were defined and examined: 1) Zone "Alpha" with incipient to advanced parapapillary chorio-pigmentepithelio-retinal atrophy - characterized by irregular hypo- and hyperpigmentation - was statistically proven in the control group (0.60 +/- 0.44 mm2; p less than 0.05; Wilcoxon-Mann-Whitney test) to be smaller than in the glaucoma group (0.81 +/- 0.70 mm2). It increased significantly (p = 0.0000) with advancing glaucoma stage. In the glaucoma and normal group it was broadest in the temporal horizontal sector (p less than 0.001; Wilcoxon test), followed by the temporal lower (p less than 0.001), temporal upper (p less than 0.001) and nasal sectors (p less than 0.001). There was no significant difference in prevalence between the two groups. 2) Zone "Beta" with subtotal to total parapapillary chorio-pigment-epithelio-retinal atrophy was also smaller in the normal eyes (0.18 +/- 0.52 mm2, prevalence: 20.0%; p = 0.0000) than in the glaucomatous ones (0.85 +/- 1.42 mm2, prevalence 66.7%) and was also, in both groups, broadest in the temporal horizontal sector, followed by the temporal lower, temporal upper and nasal sectors. In the control group it was smaller than zone "Alpha" (p less than 0.00001), while in the glaucoma group there was no difference. 3) The difference between normal eyes and earliest glaucoma stage I was for zone "Beta" (p = 0.0000); the difference between the normal eyes and those of glaucoma stage II was significant for both zones (p = 0.0000 and p less than 0.05, respectively). In both groups and in all glaucoma stages both zones were larger in the lower half of the optic disk than in the upper half. 4) "Conus pigmentosus" and the peripapillary scleral rim in normal and glaucomatous eyes showed no significant difference as regards their area and frequency. The parapapillary chorio-pigmentepithelio-retinal alterations are precursors of, or are equivalent to the so-called "halo glaucomatosus".(ABSTRACT TRUNCATED AT 400 WORDS)

[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)]. / Parapapillärer retinaler Gefässdurchmesser. II. Kaliberverminderung in Glaukomaugen (Eine papillometrische Studie von 309 Augen mit Glaucoma chronicum simplex gegenüber 264 Normalaugen).

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.

Pseudopapilledema associated with abnormally small optic discs.

Using Littmann's method for correcting the magnification of central fundus photographs, we determined the absolute size of 35 unselected optic discs with pseudopapilledema. The optic disc area (1.95 +/- 0.33 mm2 (mean and SD)) was significantly (P less than 0.001, Student's t-test ) smaller than standard values of normal unselected optic nerve heads (2.73 +/- 0.76 mm2). There was no cupping in the discs with pseudopapilledema. Coefficients of variation for intraobserver re-evaluation were 0.045, and for interobserver re-evaluation 0.08. The markedly reduced optic disc size coincide with an abnormally small optic nerve scleral canal may inhibit the intraaxoplasmatic flow with secondary swelling of the juxtapapillary optic nerve fibers. This may lead t o prominence and indistinct borders of the optic disc. Pseudopapilledema might be related to optic nerve head drusen, which are also associated with abnormally small optic discs.

[Parapapillary diameter of retinal vessels. I. Estimating the size of the optic papilla (a papillometric study of over 264 normal eyes)]. / Parapapillärer retinaler Gefässdurchmesser I. Abschätzung der Papillengrösse (Eine papillometrische Studie über 264 Normalaugen).

The diameter of the temporal superior and inferior retinal artery and vein were measured at the optic disk border and 2 mm from the disk center in 264 nonselected normal eyes on the basis of photographs, with correction of magnification. Additionally, the individual ocular magnification factor was determined by Littmann's method. The mean caliber of the artery was 0.113 +/- 0.019 mm at the disk border and 0.118 +/- 0.023 2 mm from the disk center. The corresponding values for the vein were 0.149 +/- 0.026 mm and 0.159 +/- 0.026 mm. The correlations between vessel caliber and disk size were not significant, but the relationship between disk size and the quotient of vessel diameter divided by disk size was highly significant (p less than 0.0001). Vessel diameter can therefore be taken as an independent unit for determining optic disk size in relative and approximately also in absolute units. Thus, mean horizontal disk diameter (1.77 +/- 0.33 mm) corresponded to 16.3 +/- 3.5 artery and 12.3 +/- 2.6 vein diameters (measured at the optic disk border). The mean individual ocular magnification factor was 0.302 +/- 0.017, with a Gauss standard distribution. If the optical characteristics of a photographed eye are not known and the ocular magnification factor is assumed to be 0.302, then 68.3% of all eyes will be covered with an inaccuracy of 5.6% and 95.5% of all eyes with an inaccuracy of 11.2%.

Anterior ischemic optic neuropathy: nonarteritic form in small and giant cell arteritis in normal sized optic discs.

By estimating cup/disc ratios in fellow eyes it has been assumed that nonarteritic anterior ischemic optic neuropathy (AION) occurs more often in small optic nerve heads. Correcting the photographic magnification we used absolute size units to measure 33 affected and 25 fellow optic discs with nonarteritic AION and 7 affected and 7 fellow optic nerve heads with arteritic AION. The affected and fellow discs with nonarteritic AION (2.37 + -0.29 mm2 and 2.31 + -0.31 mm2) were significantly (p less than 0.001, Mann-Whitney-test) smaller than 457 normal optic nerve heads (2.69 + -0.70 mm2). They were significantly (p less than 0.001; Mann-Whitney-test) larger than optic nerve heads with pseudopapilledema or drusen. Affected and fellow optic nerve heads with arteritic AION were not significantly different in size from normal discs but significantly (p less than 0.005) larger than the discs affected by nonarteritic neuropathy. There were no significant form differences between the pathologic and normal discs. Optic disc morphometry can be helpful in the differentiation of nonarteritic and arteritic AION: Nonarteritic AION occurs more often in small optic discs, arteritic AION is more often in normal sized optic nerve heads.

Optic disc morphometry in chronic primary open-angle glaucoma. I. Morphometric intrapapillary characteristics.

Four hundred twenty-seven optic discs of 233 unselected patients suffering from chronic primary open-angle glaucoma were morphometrically evaluated and compared with the optic nerve heads of 253 unselected normal subjects. Only one randomly chosen eye per patient was taken into consideration. We found that glaucoma leads to a change in the characteristic configuration of the neuroretinal rim that in normal eyes is significantly (P less than 0.001) largest at the lower disc pole, smaller at the upper and nasal disc side, and smallest in the temporal disc region. Based on this information, significant (P less than 0.001) morphometric differences between "early" glaucomatous and normal discs are: (a) the neuroretinal rim area in the lower temporal disc sector is smaller than in the upper temporal disc sector; the smallest rim width is outside the horizontal temporal disc sector ("pathognomonic"); the quotient of horizontal to vertical c/d ratio is lowered; and (d) the lower temporal, upper temporal, and total rim area are decreased. No significant difference in overall optic disc size and form exists between normal and glaucomatous eyes. Smaller optic nerve heads are not more susceptible to glaucoma.