Cataract diagnosis by measurement of backscattered light.

We present a portable optical cataract assessment technology which measures with a circular photodetector the fraction of light scattered backwards by the human eye lens when illuminated by a laser diode. As our signal arises directly from the fundamental pathology-increased scattering in the lens-it directly assesses cataract extent and progression. Initial clinical results in undilated human eyes show device reading correlations in agreement with clinical examination and Scheimpflug photography.

Variability in the kinesin light chain 1 gene may influence risk of age-related cataract.

PURPOSE: Kinesin-mediated cargo vesicle transport is fundamental to the maintenance of a proper lens fiber structure, which is essential for the transparency of the lens. Here, we test the hypothesis that the rs8702 polymorphism in the kinesin light chain 1 gene (KLC1), previously linked to Alzheimer disease (AD), may play a role in cataractogenesis. METHODS: Patients with nuclear (n=76), cortical (n=154), posterior subcapsular (n=117), and mixed (n=148) cataract as well as 183 controls were analyzed for the KLC1 rs8702 polymorphism using the dynamic allele-specific hybridization (DASH) technique. RESULTS: The GG genotype of rs8702 was significantly over-represented among cataract patients as compared to controls (63% versus 52%, respectively, p=0.008) and associated with an age-adjusted odds ratio for cataract development of 1.61 (95% confidence interval 1.12-2.31). This association was not confined to any particular cataract type. CONCLUSIONS: The KLC1 gene may be a novel susceptibility gene for age-related cataract.

Apolipoprotein E polymorphisms in patients with primary open-angle glaucoma.

PURPOSE: To investigate apolipoprotein E (APOE) polymorphisms, which are known to influence the risk of Alzheimer disease (AD), in patients with primary open-angle glaucoma (POAG). DESIGN: Retrospective case-control association study. METHODS: Patients with POAG (n = 242) and controls (n = 187) were analyzed for the APOE epsilon 2/epsilon 3/epsilon 4 polymorphisms using minisequencing technique. RESULTS: The Alzheimer-associated APOE epsilon 4 allele had similar frequencies in the POAG group and in the control group. There was no difference between cases and controls with regard to APOE genotypes. CONCLUSIONS: If a common pathogenic mechanism exists for the two age-related neurodegenerative diseases, POAG and AD, it does not involve APOE polymorphisms.

Methylenetetrahydrofolate reductase genetic polymorphisms in patients with cataract.

PURPOSE: Hyperhomocysteinemia is commonly associated with polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene. The level of homocysteine can be lowered by dietary intake of folate. A protective effect of folate supplementation has been reported against cataract. Here we investigate MTHFR polymorphisms in human cataract. DESIGN: Retrospective case-control association study. METHODS: Patients with nuclear (n = 77), cortical (n = 155), posterior subcapsular (n = 119), and mixed (n = 151) cataract, and 187 controls were analyzed for the MTHFR 677C-->T and 1298A-->C polymorphisms using minisequencing technique. RESULTS: The wild-type MTHFR 677CC/1298AA genotype was strongly overrepresented among cataract cases (P = .003). This effect was most pronounced in the mixed cataract group (P < .001). Hyperhomocysteinemia-associated genotypes had similar frequencies in cataract and control groups. CONCLUSIONS: The previously reported protective effect of folate against cataract is not due to overrepresentation of hyperhomocysteinemia-associated MTHFR genotypes. Instead, the strong predominance of wild-type MTHFR in cataract may suggest impaired DNA synthesis as a cataractogenic factor.

Prevalence of exfoliation syndrome in Estonia.

PURPOSE: To estimate the prevalence of exfoliation syndrome (XFS) in Estonia. METHODS: A total of 766 residents, representing the demographics of Tartu, Estonia, were chosen by random sampling from the Estonian Population Database, and invited to participate in this study. Each patient underwent careful slit-lamp examination including applanation tonometry before and after pupil dilatation. Presence of XFS was confirmed after mydriasis as typical white-gray fluffy material on the anterior lens surface, and on the pupillary border as well on the corneal endothelium. RESULTS: A total of 424 subjects, 277 female and 147 male, participated in this study. The median age was 70 years (70 years in women and 71 years in men). The overall prevalence of XFS among the study participants in 1 or both eyes was 25.5% (25.2% in men and 25.6% in women). Intraocular pressure measured before and after dilatation was significantly higher in the XFS group. Glaucoma was significantly more frequent in the XFS group than the non-XFS group; 35.7% and 11.3%, respectively. Fifty percent of all patients with glaucoma had exfoliative glaucoma. Cataract was detected in 57.0% of cases in the XFS group compared to 39.5% in the non-XFS group (p=0.002). We found similar prevalence of systemic diseases in both groups for both genders. There was no difference between the 2 groups in visual acuity. CONCLUSIONS: In this population-based cross-section study, XFS was found to be a frequent finding in Estonia. Exfoliation syndrome is a risk factor for glaucoma and cataract formation.

Exfoliation syndrome as a risk factor for corneal endothelial cell loss in cataract surgery.

PURPOSE: To compare the influence of various cataract surgery pre-, intra-, and postoperative characteristics to cornea endothelium and thickness in patients with and without exfoliation syndrome (PEX). METHODS: In this prospective study 27 consecutive patients with and 26 patients without PEX as a control group scheduled for cataract surgery were studied. The corneal endothelial cells were evaluated preoperatively and postoperatively at 1 day and 1 month after surgery using noncontact specular microscopy. Intraoperative parameters of operation time, phacoemulsification (phaco) time, phaco power and amount of balanced salt solution (BSS) were recorded. The effects of age, axial length, anterior chamber depth (ACD), and lens thickness were evaluated. RESULTS: There were no significant preoperative differences in endothelium morphology between the two groups. The mean endothelial cell loss 1 month after surgery was 18.1% in the PEX group and 11.6% in the control group (p = 0.06). Phaco time and used BSS values were significantly higher in patients with PEX but had no significant influence on endothelial cell loss. In regression analysis phaco power (p = 0.02) and age (p = 0.004) had a significant influence on endothelial cell loss. PEX in interaction with overall phaco impact had a negative influence on endothelial cell loss (p = 0.05). CONCLUSIONS: PEX as a main effect was not found to have a negative influence on endothelial cell loss. However, PEX in cases of high phaco impact significantly increases the risk of endothelial cell loss.

Optic disc biomorphometry with the Heidelberg Retina Tomograph at different reference levels.

PURPOSE: The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser tomograph that produces high resolution optical section images of the optic disc and central retina. Measurement accuracy and reproducibility is good. Several of the stereometric variables depend on the definition of a reference plane level. The purpose of the present study was to evaluate the four different reference levels in terms of their advantages and disadvantages in clinical work. METHODS: Sixty-seven randomly chosen eyes belonging to 67 subjects were included in this study. Forty of the eyes were healthy and 27 had glaucoma. The HRT with software versions 1.09 and 1.11 was used to acquire and evaluate topographic measurements of the optic disc. Image analysis was performed at four different reference levels: 320 microm fixed offset reference level (REFd) (version 1.09), an individually determined reference level (REFi), a papillo-macular reference level (REFm) and a flexible reference level (REFf) (version 1.11). ANOVA was used to determine differences in the topographic parameters between the reference levels. RESULTS: In terms of the healthy eyes, all the variables using different reference levels give rather similar results. However, with advanced glaucoma the measurement values provided with REFd are clearly different to those of the other reference levels. The measurement values using REFm and REFf provide fairly similar results in all clinical groups. REFf indicates the lowest point in the segment between 350 degrees and 356 degrees along the contour line and thus provides the most stable and clinically useful reference level at present. CONCLUSION: At present, the flexible reference level REFf gives the most reliable and adequate HRT measurement values, both in normal and in glaucomatous eyes.