Biomedical subjects

G C Gusek

Publications and source records attributed to G C Gusek.

At least 19 recordsLinked to original sources

PubMed1991

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.

Adolescent↗

PubMed1990

[Retinal vascular occlusions are independent of optic disk size. A morphometric study of 140 patients].

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.

Aged↗

PubMed1989

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.

Adult↗

PubMed1989

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.

Adolescent↗

PubMed1989

[Planimetry of glaucomatous, para-papillary, chorio-pigment epithelial retinal atrophy].

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.

Adult↗

PubMed1989

[Correlation of intra- and para-papillary glaucomatous changes--a planimetric study of 200 normal and 450 glaucoma eyes].

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.

Choroid↗

PubMed1988

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.

Aged↗

PubMed1988

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.

Adolescent↗

PubMed1988

Optic disc morphometry in chronic primary open-angle glaucoma. II. Correlation of the intrapapillary morphometric data to visual field indices.

The intrapapillary morphometric data of 290 optic nerve heads of 158 patients with chronic primary open-angle glaucoma and of 253 unselected normal subjects were correlated with the visual field indices of Octopus program 32,34-Delta. Only one eye per patient was considered. Significant correlations (P less than 0.001) were revealed for the neuroretinal rim (NRR) area as a whole and in four defined disc sectors, the ratio of lower temporal to upper temporal rim area, the rim width, the optic cup area and diameters, the horizontal and vertical cup/disc (c/d) ratios, and the quotient of horizontal to vertical c/d ratio. Correlation coefficients ranged between 0.30 and 0.77. They were highest for the rim area of the inferior temporal disc sector, followed by the superior temporal, nasal, and temporal sectors. There were no correlations for the optic disc size and form. The topographic morphometry of the intrapapillary optic disc structures was unremarkable in four glaucomatous eyes with small discs.

Adolescent↗

PubMed1988

Optic disk morphometry in high myopia.

The optic nerve head in highly myopic eyes is distinctly different from normal optic disks. We performed magnification-corrected morphometry of photographs of 51 optic nerve heads in highly myopic eyes (myopic refraction of more than -8.00 diopters). Mean refraction was -15.49 +/- 5.76 diopters (range, -8.00 to 28.00 diopters), mean age 63.0 +/- 12.1 years (range, 27-87 years). The disks were significantly (P less than 0.000001; Wilcoxon-Mann-Whitney test) larger and more ovally configurated than 457 unselected normal optic nerve heads with a myopic refraction of less than -8.00 diopters. Refraction, size of the disk, and area of the parapapillary region with chorioretinal atrophy were significantly (P less than 0.00001) correlated with each other. The parapapillary vessel diameter was independent from the disk size. Highly myopic disks can be regarded as secondary acquired macrodisks, the size of which is correlated with refraction and possibly age. They should be differentiated from secondary, acquired macrodisks in congenital glaucoma and from primary macrodisks. As in normal eyes, the parapapillary vessel caliber can be used to estimate the optic disk size in relative and approximately absolute units.

Aged↗

PubMed1988

Variability of the real dimensions of normal human optic discs.

Using Littmann's method for correcting the magnification of central fundus photographs, we evaluated planimetrically the color slides of 88 unselected optic discs without evidence of any optic nerve disease. High myopes (less than -8.00 diopters) had been excluded. Mean optic disc area measured 2.89 +/- 0.76 mm2 (minimum 0.86 mm2, maximum 5.39 mm2), mean cup area 0.63 +/- 0.64 mm2 (minimum 0.00 mm2, maximum 3.10 mm2) and mean neuroretinal rim area 2.26 +/- 0.58 mm2 (minimum 0.86 mm2, maximum 3.84 mm2). Horizontal disc diameter ranged from 0.91 mm to 2.42 mm (mean 1.79 +/- 0.27 mm) and vertical diameter from 1.08 mm to 2.76 mm (mean 1.97 +/- 0.29 mm). Coefficients of variation of the method's reproducibility were 0.03 for intraobserver and 0.03 for interobserver determination. Regarding the Gaussian distribution curve based on these preliminary data, microdiscs can be defined as being smaller than 1.4 mm2 (mean minus two standard deviations) and macrodiscs as being larger than 4.4 mm2 (mean plus two standard deviations).

Adolescent↗

PubMed1988

Size of the optic nerve scleral canal and comparison with intravital determination of optic disc dimensions.

Diameters, area, and form of the optic nerve scleral canal were measured in 107 freshly enucleated, unfixed, human donor eyes. Macrophotographs of the sectioned posterior fundus pole were provided with a millimeter scale and evaluated planimetrically. They revealed a surprising variation: area: 2.59 +/- 0.72 mm2 (minimum 0.68 mm2, maximum 4.42 mm2); minimal diameter: 1.67 +/- 0.72 mm; maximal diameter: 1.92 +/- 0.32 mm. The mean form factor was 0.92 +/- 0.11 and the quotient of minimal to maximal diameter 0.86 +/- 0.11, indicating a slightly oval nearly round form. The coefficients of variation of the method's reproducibility were 0.005 for intraobserver and 0.02 for interobserver determination. The size values of these optic nerve scleral canals were not significantly (Wilcoxon-Mann-Whitney test) different from than those of 100 unselected optic discs that had been determined intravitally using Littmann's method. This indicates the reliability of Littmann's method for the intravital measurement of the optic nerve head in absolute dimensions.

Adult↗

PubMed1988

[Parapapillary diameter of retinal vessels. I. Estimating the size of the optic papilla (a papillometric study of over 264 normal eyes)].

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%.

Adolescent↗

PubMed1988

[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.

Adolescent↗

PubMed1988

[The parapapillary region of normal and glaucoma eyes. I. Planimetric values of 312 glaucoma and 125 normal eyes].

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)

Adolescent↗

PubMed1988

[Qualitative morphologic characteristics of normal and glaucomatous optic papillae].

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.

Adolescent↗

PubMed1988

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.

Adolescent↗

PubMed1988

Correlations of the neuroretinal rim area with ocular and general parameters in normal eyes.

The neuroretinal rim as equivalent of the retinal nerve fibers is the target in the evaluation of glaucomatous optic nerve heads. Its area was measured in absolute size units using photographs of 234 normal optic disks and correcting the photographic magnification according to Littmann's method. High myopic eyes (less than -8.00 dptr) were excluded. The mean rim area was 2.09 +/- 0.60 (0.80-3.80 mm2). It was significantly correlated (p less than 0.00001) to the optic disk area. In optic disks without cupping, the neuroretinal rim area was identical with the disk area (r = 1.0, slope of the regression line = 1.0). In disks having cups with temporal flat slopes, the rim area increased by a factor of 0.71 with the disk size, in disks with circular steep cups, by a factor of 0.26. This interindividual variability and the correlations between rim and disk area might be clinically important for morphometry of glaucomatous optic nerve heads. There were no significant correlations between rim area and age, sex, refraction or axial length.

Adolescent↗