Association of ocular pressure and optic disc cup volume with red blood cell sodium-potassium ATPase inhibition.

PURPOSE: To determine if there were significant differences between the number of red blood cell ouabain binding sites in normals and untreated ocular hypertensives plus one open-angle glaucoma patient. METHODS: We measured the binding of (3)H ouabain to erythrocyte membranes of 23 normals, 25 ocular hypertensives and one open-angle glaucoma. We also measured the levels of plasma cortisol and digoxin in these subjects. Characteristics of cupping of the optic disc and thickness of the retinal nerve fiber layer, as well as area of optic disc pallor of these subjects were measured by stereophotogrammetry and by computerized image analysis from single and stereo photographs. RESULTS: The number of (3)H ouabain binding sites was observed to be significantly less in the ocular hypertensives and one glaucoma compared to the normals (p = 0.0009). In multi-variate analyses, to determine what other factors affected this difference, there was a significant negative association with mean intraocular pressure (p = 0.003) (average of both eyes) and total cup volume (average of both eyes) (p = 0.005), diagnosis of ocular hypertension and glaucoma (p = 0.0005) and male gender (p = 0.019). There was a significant positive association with plasma cortisol levels (p = 0.048), and diastolic blood pressure (p = 0.037). CONCLUSIONS: The number of (3)H ouabain binding sites in red blood cells decreases significantly with increasing ocular pressure and increasing cup volume indicating the possible presence of an increased systemic endogenous digoxin-like inhibitor and/or difference in the isozymes of Na(+), K(+)-ATPase which may be associated with increased levels of plasma cortisol in ocular hypertensives and glaucomas.

Decrease of optic disc cupping and pallor of ocular hypertensives with timolol therapy.

PURPOSE: The purpose of this study was to determine whether timolol drops compared to placebo drops had a significant effect on optic disc cupping and pallor in ocular hypertensives. METHODS: Thirty-seven ocular hypertensives were randomly assigned to placebo or 0.5% timolol drops to both eyes in a double masked clinical trial. Measurements of ocular pressure and photographs of the optic disc for cupping by photogrammetry and pallor by computerized image analysis were made at about 3 month intervals, for 18 to 24 months of follow-up. RESULTS: None of the subjects developed visual field loss when tested with the Goldmann perimeter by kinetic and static means at six month intervals. Subjects treated with timolol developed a significant decrease in ocular pressure and a significant decrease in optic disc cupping with a smaller decrease in pallor compared to subject treated with placebo. Multivariate analyses indicated that the decrease of optic disc cupping and pallor was not associated with the ocular pressure on treatment or the decrease in ocular pressure during the trial. CONCLUSION: Timolol treatment was associated with a decrease in optic disc cupping and pallor. The effect of timolol appears to be related to mechanisms other than the decrease in ocular pressure.

Reversal of optic disc cupping and pallor in patients with ocular hypertension using timolol therapy.

OBJECTIVES: We studied the quantitative effects on optic disc cupping and pallor in a double-masked, prospective clinical trial in which patients were randomized to timolol and placebo groups.

Increased preferential optic disc asymmetry in ocular hypertensive patients compared with control subjects.

The authors determined asymmetrical differences in optic disc cupping and pallor between the right and left eyes of 57 control subjects and 75 patients with ocular hypertension. Photogrammetry was used to measure the optic disc cup, and computerized image analysis was used to measure the optic disc pallor for the total disc and its quadrants. Generally, for control and ocular hypertensive eyes, the median values of cupping and pallor were significantly larger in the left eye than in the right, except for depth in the inferior quadrant (right eye minus left eye = 9.3%, P = 0.000) and pallor in the nasal quadrant (right eye minus left eye = 21.3%, P = 0.01), which were preferentially larger in the right eye than in the left in ocular hypertensive eyes. Ocular hypertensive eyes also showed a greater difference between the right and left eyes compared with control eyes for inferior depth (P = 0.06) and nasal pallor (P = 0.02). Detection of optic disc differences as a sign of ocular hypertension between the right eye and the left should evaluate the inferior and nasal quadrants of the disc.

Intraocular pressure and the rate of visual field loss in chronic open-angle glaucoma.

We measured the rate of change of visual field threshold values over time (mean follow-up, 44.9 +/- 17.4 months) by trend analysis in 40 eyes of 40 patients with chronic open-angle glaucoma. Twenty-eight eyes had stable visual fields, and two eyes had significant visual field improvement. Ten eyes had significant visual field deterioration and showed a correlation between indices of intraocular pressure (standard error of the mean, P = .02; standard deviation, P = .04; and range, P = .05) and the rate of visual field loss in the superonasal region of the visual field, such that the greater the variation of intraocular pressure the greater the rate of loss. The group losing visual fields had a higher mean visual field threshold value and significantly less optic disk pallor and cupping at the start of the study than the stable visual field group. Thus, a significant rate of visual field loss occurred at an earlier stage of the disease and showed a correlation with intraocular pressure in this stage.

Glaucomalike disks without increased intraocular pressure or visual field loss.

We studied 48 patients who had glaucomalike disks with increased cupping and pallor, superior or inferior extension of cupping and pallor and asymmetry of cupping and pallor between eyes without increased intraocular pressure or visual field loss, and open angles. We compared these patients with a randomly selected group of 48 patients with primary open-angle glaucoma. The mean age of the patients with glaucomalike disks (45.1 +/- 16.1 years) was significantly younger than the group with open-angle glaucoma (63.8 +/- 11.3 years). Of the patients with glaucomalike disks, 11 (23%) had a family history of glaucoma, 75% of 22 eyes with optic disk fluorescein angiograms had abnormal readings, and 59% of 43 eyes with retinal nerve fiber layer defects had abnormal readings. Photogrammetric measurements of the left disk cups were compared in 22 of the patients with glaucomalike disks to 16 matched patients with primary open-angle glaucoma. The only statistically significant difference was that the patients in the glaucoma group showed a larger cup area (surface opening) of the inferior quadrant. Our findings suggest that some glaucomalike disks may be one variant of primary open-angle glaucoma.

Optic disk cupping and pallor measurements of patients with a disk hemorrhage.

We evaluated whether the rate of occurrence of glaucomatous disk damage in eyes with an optic disk hemorrhage differed from the rate of occurrence in control eyes. We compared 24 patients with a disk hemorrhage to 24 control patients, who had been matched for diagnosis, disk appearance, and visual fields. Cup volume and cup-to-disk area ratio of the optic disk were measured using the stereophotogrammetric technique, and area of pallor was measured using computerized image analysis. We found that diabetes increased the probability that a patient would have a disk hemorrhage, and that a hemorrhage was associated with progression of glaucomatous disk changes in half of the cases during the mean 3.1-year follow-up period. However, the mean rate of glaucomatous disk damage in patients with a hemorrhage was not different from matched control patients. A disk hemorrhage is a sign of later disk damage, but it does not alter the rate of glaucomatous disk progression.

Measurements of reversibility of optic disc cupping and pallor in ocular hypertension and glaucoma.

Four cases are presented of young and elderly glaucoma patients who had both surgical and medical therapy and showed reversal of cupping and pallor of the optic disc. The cupping was measured by photogrammetry and the pallor by computerized image analysis from photographs of the optic disc. Two patients showed regression of visual field loss. The optic disc and visual field changes corresponded to the changes in ocular pressures, generally showing worsening with an increase in ocular pressure. With a decrease in ocular pressure there was regression of visual field loss and a decrease in cupping; pallor did not decrease consistently. The changes in cupping and pallor in some patients followed similar courses but in others behaved in an independent manner. It is proposed that these new sensitive and reproducible techniques for measuring changes in the optic disc may allow the detection of disc changes early in the disease, prior to visual field loss. If treatment is begun at this time, reversal of optic disc changes may occur.