Changes of serum calcium, phosphorus, and parathyroid hormone concentrations and ocular findings among patients undergoing hemodialysis.

There are various reports of ocular abnormalities in metabolic disorders. This study was done with the aim to investigate the relationships between the amounts of serum calcium, phosphorus, and parathyroid hormone concentrations and ocular findings in patients undergoing hemodialysis. Fifty eight patients with end stage renal failure undergoing hemodialysis were randomly selected and enrolled in this prospective study. Demographic data, history of diabetes mellitus and hypertension, and duration of hemodialysis were recorded. Serum calcium, phosphorus, alkaline phosphatase (ALP), and parathyroid hormone (PTH) concentrations were measured. Also, blood urea nitrogen (BUN) and weight of the patient was measured just before and three minutes after the hemodialysis. Patients also underwent a complete ocular examination including visual acuity, intraocular pressure (IOP), biomicroscopic examination, and fundoscopy. In univariate analysis, adverse relationships were found between the ocular hypertension and ALP concentration (P = 0.017) and also between the visual acuity and phosphorus concentration (P = 0.033). However, in multivariate regression analysis and with regard to the patients' characteristics and medical history in a multivariate model, no relationships were found between ocular findings and serum calcium, phosphorus, ALP, and PTH concentrations. No relationships were found between the serum concentrations of calcium, phosphorus, ALP, and PTH and ocular findings in patients with end stage renal failure undergoing hemodialysis.

Decreased response of plasma cortisol to intravenous metyrapone in ocular hypertension and primary open-angle glaucoma.

PURPOSE: To determine if there is a difference in response to metyrapone, which blocks the conversion of 11-deoxycortisol to cortisol in the adrenal gland between normals and ocular hypertensives (OH) plus primary open-angle glaucomas (POAG) without pigmented angles. METHODS: Intravenous metyrapone was given to 20 normals and 15 ocular hypertensives plus primary open-angle glaucomas without pigmented angles. Blood samples were obtained at 4, 6, and 8 hours after administration of intravenous metyrapone for analyses of 11-deoxycortisol and cortisol. RESULTS: The ocular hypertensives plus primary open-angle glaucoma group showed significantly lower cortisol values compared with the normal group at 6 hours (P = 0.002) but not at 4 or 8 hours. There were no significant differences between the two groups for 11-deoxycortisol values at 4, 6, or 8 hours. The percent decrease of plasma cortisol from baseline was significantly greater for the ocular hypertensives plus open-angle glaucoma group compared with the normals at 4 hours (P = 0.010) and 6 hours (P = 0.0004). Significant negative correlations were observed for the total group of subjects between levels of plasma cortisol at 6 hours and intraocular pressure, worse eye (P = 0.029), percent area of cupping, worse eye (P = 0.045), pallor, worse eye (P = 0.001), and visual field loss, worse eye (P = 0.048), so that the less the plasma cortisol, the greater the abnormality of the glaucomatous parameters. Multivariate analyses with the 6-hour plasma cortisol level as the dependent variable showed that the only significant (P = 0.0004) independent variable was the percent area of pallor, worse eye, associated with a smaller level of plasma cortisol at 6 hours. Similarly, the multiple regression models using the percent change from baseline of the 6-hour plasma cortisol value showed a significant association of larger percent decreases of plasma cortisol in the ocular hypertensives plus open-angle glaucoma compared with the normals. CONCLUSIONS: The ocular hypertensives plus primary open-angle glaucoma subjects show greater adrenal inhibition to metyrapone in the synthesis of cortisol from 11-deoxycortisol compared with normals. This observation suggests an adrenal abnormality in the ocular hypertensive plus primary open-angle glaucoma subjects.

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.