Role of the Apolipoprotein E Polymorphisms in the Development of Retinal Vein Occlusion in a Tunisian Population: A Case-Control Study.

Apolipoprotein E ( APOE) is a member of the apolipoprotein gene family. APOE is polymorphic with 3 main allelic types: ∊2, ∊3, and ∊4. Certain of these alleles have been associated with higher vascular risk. However, the association of APOE genotypes with retinal biomarkers and risk of retinal stroke is less clear. This study evaluated the role of APOE polymorphisms in retinal vein occlusion (RVO). In the present study, 2-point mutations coding amino acid residues 112 and 158 were amplified using the polymerase chain reaction (PCR) from DNA extracted from Tunisian participants. APOE genotypes were determined by multiplex PCR followed by molecular hybridization. Eighty-eight patients (26 women and 62 men) and 100 age- and gender-matched healthy participants were enrolled. The statistical study revealed a higher frequency of the ∊4 allele in patients as compared to controls (27.3% vs 9%) with a significant association of the ∊4 allele with the disease ( P < 10-3, Pa < 10-3, odds ratio [OR] = 3.8, 95% confidence interval [CI] = 2.1-6.8). The frequency of the ∊3 allele was significantly lower in the patients with RVO compared to the controls (60.2% vs 82.5%, respectively; P < 10-3, Pa < 10-3, OR = 0.32, 95% CI = 0.19-0.53). The ∊3 allele seems to be protective against the disease. There was no association between the APO ∊2 allele and RVO. The association of APOE allele and genotype with RVO requires further investigation in different populations.

Ozil® versus conventional ultrasound phacoemulsification: a randomized comparative study.

The purpose of this study is to compare and assess the performance and the postoperative outcomes of torsional mode and ultrasound (US) mode performed in the phacoemulsification of cataract with different nuclear densities. This is a randomized comparative clinical study. Two groups of 75 eyes (the first operated by Ozil(®) and the second by US) were comparable in age, gender, cataract density, corneal incision size, and intraocular lens type. We assessed peroperative parameters: US time (UST) and cumulative dissipated energy (CDE). Postoperative outcome measures were corneal edema and final best-corrected visual acuity. The UST was significantly lower in the ozil(®) group for all nucleus grades (73.43 s ± 8.3 with US vs. 46.02 s ± 23 with Ozil(®)) (p = 0.0003). The CDE was lower in the Ozil(®) group for grade III and IV cataract (p = 0.005). However, no significant difference was noted for grade II cataract (p = 0.07). Immediate postoperative corneal edema was significantly harder in the US group (p = 0.00002). The mean one month postoperative visual acuity was 0.2 ± 0.03 logMAR and 0.15 ± 0.07 logMAR, respectively, in the US group and the Ozil(®) group (p = 0.06). Ozil(®) mode seems to dissipate less energy in the eye than US mode. The visual outcome at one month is comparable in the two groups.

Thrombophilic risk factors in different types of retinal vein occlusion in Tunisian patients.

BACKGROUND: Retinal vein occlusion (RVO) is the second most common cause of vision loss because of retinal vascular disease. There are 2 types of RVO: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). The pathogenesis of RVO is multifactorial. The role of factor V Leiden (FVL) and prothrombin mutations was examined in patients with CRVO and BRVO. METHODS: FVL and prothrombin were investigated by extracting DNA of 88 patients with RVO. Sixteen of the patients were diagnosed with CRVO, 4 with hemispheric retinal vein occlusion, and 68 with BRVO. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Significant differences were found in the frequencies of the genotypes for both the FVL (G1691A) (P<10(-3), odds ratio [OR]=17.4, confidence interval [CI]=6.20-59) and prothrombin (G20210A) (P=.007, OR=5.11, CI=1.30-29) polymorphisms between RVO patients and healthy controls. Additionally, the frequency of the GA genotype for the G1691A polymorphism was significantly higher among the patients in a subset of BRVO compared with controls (P<10(-3), OR=21.4, CI=7.34-74.2). However, no statistically significant differences were found in the frequencies of the prothrombin G20210A polymorphism between the BRVO group and healthy controls (P=.09, OR=3.13, CI=64-19.9). The frequency of both G1691A and G20210A genotypes among the patients of a CRVO subgroup was significantly higher compared with controls (P<10(-3), OR=11.4, CI=2.94-44.2; P=.007, OR=10.8, CI=2.15-54.1, respectively), suggesting an association between these polymorphisms and CRVO. CONCLUSIONS: Large study would be required to understand completely the contribution of these markers in the risk of all types of RVO.

Association of methylenetetrahydrofolate reductase (A1298C and C677T) polymorphisms with retinal vein occlusion in Tunisian patients.

The role of two polymorphisms C677T and A1298C of the methylenetetrahydrofolate reductase (MTHFR) gene in the etiology of retinal vein occlusion (RVO) has not been adequately clarified. The aim of this study was to examine the prevalence of these polymorphisms among RVO Tunisian patients with and without systemic risk factors. Seventy-two patients with retinal vein occlusion (RVO) were studied. The control group included140 people matched for age, sex, and risk factors. Participants in the study were genotyped for the MTHFR C677T and A1298C polymorphisms. The genotyping was performed by PCR-RFLP. No significant differences were found in the frequencies of the three genotypes (AA, AC, CC) of the MTHFR A1298C polymorphism between RVO patients and healthy controls. However, the prevalence of the group of mutated genotypes (AC+CC) of the missense variant MTHFR A1298C was significantly different between patients and controls (16.67% vs. 6.42%, p=.01). Additionally, the frequency of the CT genotype as well as the group of combined mutated genotypes (CT+TT) for the C677T variant was significantly higher among RVO patients compared with controls (p<10(-3), p<10(-3)). This suggests an association between this polymorphism and RVO. Large study populations would be required to understand more completely the contribution of these markers in the risk of RVO.