Impaired nitric oxide production in patients with primary open-angle glaucoma.

BACKGROUND: Glaucoma is an optic neuropathy induced by many factors. Vascular dysfunction is involved in the mechanism underlying glaucoma. AIM: To determine the involvement of nitric oxide (NO), which is implicated in the regulation of ocular blood flow, in primary open angle glaucoma (POAG). Furthermore, lactate and uric acid (UA) levels were investigated. METHODS: Concentrations of NO, UA and lactate in plasma and aqueous humor (AH) were measured in 214 Tunisian patients (100 patients with POAG and 114 subjects with cataract as control group). NO metabolites, nitrate and nitrite (NOx) production were determined using the Griess reaction. UA and lactate concentrations were measured using enzymatic- colorimetric methods. RESULTS: NOx concentrations in patients with POAG were significantly lower compared to cataract group in plasma (5.23±1.55 µmol/L vs 18.35±6.87 µmol/L, p=0.01) and AH (20.54±7.41 µmol/L vs 45.25±10.92 µmol/L, p=0.02). Plasma and AH levels of lactate and UA were significantly higher in glaucoma patients than in control subjects. CONCLUSIONS: In the present study, decreased NO and increased UA and lactate levels were found in the AH and plasma of POAG patients compared to control subjects. These data suggest a possible involvement of these factors in glaucoma.

The Role of Genetic Variants (rs869109213 and rs2070744) Of the eNOS Gene and BglII in the α2 Subunit of the α2ß1 Integrin Gene in Diabetic Retinopathy in a Tunisian Population.

Purpose: In this study, we investigated the association of two polymorphisms (rs869109213 and rs2070744) in the eNOS gene and one polymorphism BglII in the α2ß1 integrin gene (ITGA2) with the risk of diabetic retinopathy (DR) in a Tunisian population. Methods: The study investigated of 110 type 2 diabetes mellitus (T2DM) and 127 DR patients. The genotypes of the eNOS 4b/4a (rs869109213) and -786T/C (rs2070744) polymorphisms and of the BglII polymorphism of ITGA2 were studied using the PCR or PCR-RFLP method. Results: The genotype distributions of the two polymorphisms in eNOS 4b4a and eNOS (-786T/C) were significantly different between T2DM and DR patients (p < .004 and p = .033, respectively). These polymorphisms were associated with the risk of DR (OR = 2.65, 95%CI [1.45-4.84], p = .002) for the eNOS 4b4a genotype and (OR = 2.43, 95%CI [1.06 - 5.56], p = .036) for the CC genotype of the eNOS gene (-786T/C). Similarly, the genotype distribution of the BglII polymorphism was significantly different between the two groups studied (p = .037). This polymorphism was associated with an increased risk of DR (OR = 4.03, 95% CI [1.17 - 7.85], p = .022) for BglII(+/+). Conclusion: The present study suggests that the polymorphisms 4b4a and -786T/C in the eNOS gene might be associated with DR. In addition, the BglII polymorphism in the ITGA2 gene was a risk factor for DR.

[Laser contribution in angle closure glaucoma]. / Apport du laser dans les glaucomes aigus par fermeture de l'angle.

BACKGROUND: A better understanding of angle-closure glaucoma mechanisms is necessary to indicate the appropriate treatment. AIM: the aim of our study is to discuss the laser indication in various type of angle-closure glaucoma. METHODS: The study investigate 25 eyes of 22 patients who had an angle-closure glaucoma. The mechanisms are an anterior chamber angle blockage in 19 eyes, a plateau iris structure in 4 eyes and a nanophthalmos in 2 eyes. RESULTS: Laser peripheral iridotomy is the most used technic; it was practised in 19 eyes. Argon laser iridoplasty was practised in 4 cases of plateau iris structure and in 2 patients who had a residual angle closure with a functional iridotomy. CONCLUSION: Laser is an effective alternative in the treatment of angle-closure glaucoma and can alleviate the need for high-risk filtering surgery.

Efficacy of the Ahmed glaucoma valve implant in eyes with refractory glaucoma.

BACKGROUND: Implantation of glaucoma drainage devices is currently considered as a good alternative to the traditional treatment of refractory glaucoma. AIM: To evaluate the efficacy and safety of the Ahmed glaucoma valve implant in eyes with refractory glaucoma. METHODS: This retrospective study included 27 eyes from 27 patients with refractory glaucoma treated with the Ahmed glaucoma valve implant between February 1995 and January 2000. We reviewed the final intraocular pressure and incidence of complications in all patients. RESULTS: The most common aetiology of refractory glaucoma was open-angle glaucoma (48.1%) followed by neovascular glaucoma (29.6%). After a mean follow-up of 35.74 months (range 9-52 months), the mean intraocular pressure decreased from 35.66 mm Hg before surgery to 14 mm Hg on the last follow-up visit after surgery. Thus, the procedure was successful in 69.23% of cases. Nine patients (33.33%) achieved reduced intraocular pressure without additional antiglaucomatous medication. Transient postoperative hypotony of < 5 mm Hg occurred in 14.8 % of patients. This was, with transient hyphaema, the most common postoperative complication. CONCLUSION: The Ahmed glaucoma valve implant seems to be effective and safe for the management of refractory glaucoma. However, it is less effective in case of neovascular glaucoma.

Congenital retinal arterial macrovessel and congenital hamartoma of the retinal pigment epithelium.

We describe a 15-year-old girl with congenital simple hamartoma of the retinal pigment epithelium associated with congenital retinal arterial macrovessel crossing the macular region. To our knowledge, there are no reports of this association.