Heredity in primary open-angle glaucoma

The past years have seen considerable progress in the characterization of hereditary factors in primary open-angle glaucoma. Epidemiologic studies strengthened our knowledge of the hereditary factors in this multifactorial disease. Several loci in the human genome have been described, which segregate with different glaucoma phenotypes. Mutations of the MYOC/TIGR (myocilin/trabecular meshwork inducible glucocorticoid response) gene on chromosome 1q account for most, but probably not all, cases of glaucoma linked to chromosome 1q, and other additional pathologic factors may be implicated. The properties of the normal myocilin protein point to a crucial role in the regulation of intraocular pressure. However, in spite of the knowledge obtained so far, routinely performed genetic screening of patients at risk for primary open-angle glaucoma is not yet clinically useful.     

Phacoviscocanalostomy in pseudoexfoliation glaucoma versus primary open-angle glaucoma

Objective: To compare the outcome of phacoviscocanalostomy in Pseudoexfoliation glaucoma (PEXG) versus that in primary open-angle glaucoma (POAG).Design: Prospective comparative study.Participants: Sixty eyes of 60 patients who underwent phacoviscocanalostomy for cataract and medically uncontrolled PEXG (30 eyes) or POAG (30 eyes).Methods: Success rate was based on intraocular pressure (IOP) reduction and need for antiglaucoma medication. Visual acuity (VA) and complication rates were secondary outcomes.Results: The mean follow-up was 19.7 months (range, 12–36 months). The mean IOP values in both groups were significantly less than the preoperative values at all postoperative intervals (p < 0.001). From 1 month onward, the decrease in IOP was more dramatic in PEXG eyes than in POAG eyes (p < 0.05). At last visit, the mean percentage of IOP reduction was 49.7% in the PEXG group and 30.9% in the POAG group. All study eyes required decreased antiglaucoma medications and showed improved VA postoperatively. Transient complications included Descemet's membrane microperforations, macroperforation, zonular dehiscence, and postoperative IOP spike. No eyes developed trabeculectomy-type bleb, hyphema, fibrin exudation, or bleb-related complications.Conclusions: Phacoviscocanalostomy achieved excellent IOP control and VA improvement in both PEXG and POAG groups. PEXG demonstrated greater IOP reduction and fewer postoperative medications than POAG. The complication rate was low and did not affect surgical outcome. Phacoviscocanalostomy can be an effective and safe surgical alternative to phacotrabeculectomy in both groups of patients.     

Hypothyroidism and primary open-angle glaucoma

OBJECTIVE: To test if there is an association between hypothyroidism and primary open-angle glaucoma (POAG) and the utility of routine study of thyroid function in these patients. METHODS: The study was conducted in a case-control fashion. Seventy-five consecutive patients with a previous diagnosis of POAG and 75 control patients were prospectively evaluated for hypothyroidism. The levels of thyroid-stimulating hormone and free thyroxin were measured. RESULTS: Hypothyroidism was revealed in only 2 patients with previous diagnosis of POAG (2.67%) and 3 patients of the control group (4%). CONCLUSIONS: As we have not been able to demonstrate the previously reported relationship between hypothyroidism and POAG, we cannot recommend the systematic screening for hypothyroidism in patients with POAG.     

Oxidative stress in primary open-angle glaucoma

PURPOSE: To analyze oxidative stress in primary open-angle glaucoma (POAG). MATERIAL AND METHODS: A case-control study including 90 eyes of 90 patients who needed antiglaucomatous surgery in the course of POAG (glaucoma group, n=50) and from patients who were operated of nonpathologic cataracts (cataract group, n=40). Free radical formation via lipid peroxidation by malondialdehyde-thiobarbituric acid reactive substances (MDA-TBARS) test and total antioxidant status in the aqueous humor samples of both groups were determined. Statistical analyses were carried out in relation to MDA-TBARS and total antioxidant status and their correlations with glaucoma risk factors. RESULTS: Significantly higher MDA-TBARS were detected in the POAG with respect to the comparative group of cataract subjects (P<0.001). Antioxidant activity was significantly lower in the POAG than in the cataract group (P<0.001). CONCLUSIONS: Aqueous humor samples may be used for determining oxidative and antioxidant status in pathologic processes. Glaucomatous eyes had a significant increase in oxidative status and decreased antioxidant activity in the aqueous humor than the cataract eyes. Oxidative stress may play a pathogenical role in the POAG.     

Blood viscosity in primary open-angle glaucoma

To determine whether hemorrheologic factors play a part in optic nerve cupping and visual field loss in glaucoma, blood viscosity was measured at three shear rates in 27 patients with primary open-angle glaucoma and 18 healthy control subjects matched for sex, mean arterial blood pressure and smoking habits. The study was conducted between 1984 and 1986. The mean viscosity was significantly higher in the glaucoma group than in the control group at all three shear rates. The possible relevance of raised blood viscosity as a causal factor in optic nerve cupping in patients with glaucoma is discussed.     

Race and primary open-angle glaucoma

A comparison of racial distributions for three groups of patients showed that 115 of 140 patients (81.6%) with open-angle glaucoma, 221 of 392 patients (56.4%) with ocular hypertension, and 1,028 of 2,109 patients (48.7%) in a random sample were black. Average age at diagnosis was significantly (P = .006) higher for whites than for blacks (69.1 years vs 63.7 years). Black patients with primary open-angle glaucoma had a significantly larger mean cup-disk ratio (P less than or equal to .002) and a higher but not significantly higher mean intraocular pressure at the time of diagnosis. Advanced glaucomatous visual field loss was more frequent at the time of diagnosis in blacks (43 of 129 patients or 33.3%) than in whites (five of 27 patients or 18.5%), but this difference was not significant.     

Genetic markers in primary open-angle glaucoma

Purpose: To investigate possible associations between genetic markers and Primary Open-Angle Glaucoma (POAG). Methods: A number of genetic markers were typed in 84 unrelated patients with POAG and compared with a random sample of healthy individuals. The markers were Transferrin, Group Specific Component, G1m (1), G1m (2) and G3m (5) Allotypes, Adenylate Kinase, Adenosin Deaminase, Glyoxalase I and Acid Phosphatase and PCR-based markers HLA-DQA1 and D1S80. Results: No significant differences were found except the strong association between the group of POAG patients and Acid Phosphatase ACP^*C allele (² = 32.86; p < 0.0001). Conclusions: Since Acid Phosphatase gene is localized to chromosome 2p23, this result could be a first comprehensive step in the localization of POAG genes.     

False-negative responses in primary open-angle glaucoma

To determine the false-negative response rate in patients with primary open-angle glaucoma (POAG) and its relationship with the mean deviation, we evaluated 286 visual fields of patients with POAG. A high false-negative response rate was found in glaucomatous patients compared with healthy controls. When the mean derivation was compared with the false-negative response rate, a logarithmic correlation was found with Pearson correlation analysis.     

Immunopathogenesis of primary open-angle glaucoma

By means of direct immunofluorescence technique the trabecular meshwork of patients with primary open-angle glaucoma, obtained at the time of filtering surgery, and the trabecular meshwork of controls were investigated for the presence of immunoglobulins and the complement component C3. In neither group were such deposits found; this indicates a lack of immunogenic mechanisms in primary open-angle glaucoma.     

Retinal oximetry in primary open-angle glaucoma

PURPOSE. To determine whether retinal vessel oxygen saturation is affected in primary open-angle glaucoma (POAG) patients. METHODS. Retinal oxygen saturation in patients with POAG was measured in retinal vessels with a spectrophotometric retinal oximeter in darkness, and visual fields were obtained. Oxygen tension (Po(2)) was calculated from oxygen saturation values. Statistical analysis was performed using Pearson's correlation and Student's t-test. RESULTS. Mean oxygen saturation in venules was higher in persons with poor visual fields (68% ± 4%, mean ± SD) than in those with good visual fields (62% ± 3%; P = 0.0018). The mean arteriovenous difference in oxygen saturation was lower in persons with poor visual fields (30% ± 4%, n = 9) than in those with good visual fields (37% ± 4%; P = 0.0003; n = 12). No correlation was found between saturation in retinal arterioles and visual field mean defect (n = 31; r = -0.16; P = 0.38). Oxygen saturation in retinal venules correlated positively with worsening visual field mean defect (r = 0.43; P = 0.015). Arteriovenous difference in oxygen saturation decreased significantly as the visual field mean defect worsened (r = -0.55; P = 0.0013). Mean Po(2) in venules was 38 ± 3 mm Hg. It was significantly higher in persons with poor visual field fields (40 ± 3 mm Hg) than in those with good visual fields (36 ± 2 mm Hg; P = 0.0016). CONCLUSIONS. Deeper glaucomatous visual field defects are associated with increased oxygen saturation in venules and decreased arteriovenous difference in retinal oxygen saturation. The data suggest that oxygen metabolism is affected in the glaucomatous retina, possibly related to tissue atrophy.     

正常眼压型青光眼与高眼压型原发性开角型青光眼是否为同一类型疾病

基于临床考虑,在《我国原发性青光眼诊断和治疗专家共识》中,将正常眼压型青光眼与高眼压型原发性开角型青光眼同归类为原发性开角型青光眼,归属于一类疾病的两个亚型,分界点在于眼压是在正常范围还是高于21 mm Hg(1 mm Hg=0.133 kPa)。但是正常眼压型青光眼与高眼压型原发性开角型青光眼是否应属同一类型疾病,眼...     

原发性开角型青光眼血流动力学研究

目的：探讨原发性开角型青光眼（primary open angle glaucoma,POAG)眼血流动力学的变化, 分析眼血流与视野、视力、眼压、杯盘比的关系。方法：利用彩色多普勒成像（color Doppler imaging,CDI)技术检测POAG患者与正常人各30例59眼的球后血流状态,其中10例,10眼行眼底荧光血管造影（fundus fluorescein angiography,FFA)检测。结果：POAG眼血流速度明显降低（P＜0．01）,血流速度与视功能具有相关性。POAG组表现FFA异常：早期视盘弱荧光,相对性、绝对性视盘局部充盈缺损, 后期视盘强荧光。结论：POAG患者视盘及视网膜血液供应不良,与视神经损害和视野缺损密切相关,首次提出CDI技术检测标准化,实现检测结果的可比性。