Meta-analysis of genome-wide association studies in multiethnic Asians identifies two loci for age-related nuclear cataract.

Age-related cataract is a leading cause of blindness worldwide, especially in developing countries where access to cataract surgery remains limited. Previous linkage and candidate gene studies suggested genetic influences on age-related nuclear cataract but few genetic markers have been identified thus far. We conducted genome-wide association studies on 4569 Asians (including 2369 Malays and 2200 Indians), and replicated our analysis in 2481 Chinese from two independent cohorts (1768 Chinese in Singapore and 803 Chinese in Beijing). We confirmed two genome-wide significant loci for nuclear cataract in the combined meta-analysis of four cohorts (n = 7140). The first locus was at chromosome 3q25.31 in KCNAB1 (rs7615568, fixed-effect Pmeta = 2.30 × 10(-8); random-effect Pmeta = 1.08 × 10(-8)). The second locus was at chromosome 21 in the proximity of CRYAA (rs11911275, fixed-effect Pmeta = 2.77 × 10(-8); random-effect Pmeta = 1.98 × 10(-9)), a major protein component of eye lens. The findings were further supported by up-regulation and down-regulation of KCNAB1 and CRYAA in human lens capsule, respectively, as the severity of nuclear cataract increases. The results offer additional insights into the pathogenesis of nuclear cataract in Asians.

Visual acuity outcomes with SA60D3, SN60D3, and ZM900 multifocal IOL implantation after phacoemulsification.

PURPOSE: To assess the near and distance visual acuity achieved with implantation of the ReSTOR SA60D3 and SN60D3 (Alcon Laboratories Inc) and Tecnis ZM900 (Abbott Medical Optics [AMO]) multifocal intraocular lens (IOL) after cataract surgery. METHODS: This is a retrospective study of 108 eyes of 54 patients who underwent uneventful bilateral phacoemulsification of cataract and IOL implantation at an ophthalmic center in Singapore by a single surgeon. Inclusion criteria were visually significant cataracts, corneal astigmatism <2.00 diopters, and no other ocular diseases. Patients received the SA60D3, SN60D3, or ZM900 multifocal IOL in both eyes. Binocular near and distance visual acuity outcomes were assessed 3 months after second-eye surgery. RESULTS: No difference in mean postoperative uncorrected and best spectacle-corrected visual acuity for distance among the groups was noted. The ZM900 lens was significantly better than both ReSTOR lenses for uncorrected near vision with 96.7% achieving N5 compared to 75% of SA60D3 patients and 83.3% of SN60D3 patients (P=.003). For distance corrected near vision, 100% of ZM900 patients achieved N5 compared to 83.3% for each the SA60D3 and SN60D3 IOLs (P=.005). No significant difference between both ReSTOR lenses for near vision was noted. CONCLUSIONS: All three IOLs provide similar uncorrected and best corrected distance visual acuity. However, the ZM900 IOL provides better binocular distance corrected and uncorrected near acuity than the SA60D3 or SN60D3. The ZM900 IOL group was more myopic preoperatively compared to the other two groups, which may be a contributing factor.

High-definition imaging of trabeculectomy blebs using spectral domain optical coherence tomography adapted for the anterior segment.

BACKGROUND: The aim of this work was to image trabeculectomy blebs using spectral domain optical coherence tomography (SDOCT). METHODS: In this prospective cross-sectional study, patients who had undergone trabeculectomy with at least 3 months of follow up were included. Blebs were imaged using an adapted SDOCT system (Cirrus HD-OCT, Carl Zeiss Meditec Inc., Dublin, CA, USA) and time domain anterior segment optical coherence tomography (ASOCT) (Visante OCT, Carl Zeiss Meditec Inc.). An observer masked to clinical data assessed the utility of SDOCT and ASOCT in visualizing structures in successful and failed blebs. RESULTS: Fifty-one eyes were imaged, of which 43 (84.3%) were successful. SDOCT showed wall thickening (93.0% vs. 67.4%, P = 0.006) and discrete hyporeflective spaces in the wall (88.4% vs. 14.0%, P < 0.0001) in a greater proportion of successful blebs than ASOCT. SDOCT showed the bleb cavity (23.3% vs. 48.8%, P = 0.02), scleral flap (34.9% vs. 90.7%, P < 0.0001), subflap space (20.9% vs. 72.1%, P < 0.0001) and ostium (9.3% vs. 88.4%, P < 0.0001) in fewer successful blebs than ASOCT. The internal ostium was not visualized in any failed bleb using SDOCT, whereas ASOCT showed the ostium in 87.5% of failed blebs (P = 0.001). SDOCT showed cystic spaces in the bleb wall in a greater proportion of successful blebs than failed blebs (88.4% vs. 37.5%, P = 0.005). CONCLUSIONS: SDOCT imaging was able to show fine superficial features in the bleb wall. However, SDOCT had limited clinical utility in that it did not provide useful information about deep features such as flap position, bleb cavity formation or patency of the subflap space and internal ostium.

Lens Opacities Classification System III: cataract grading variability between junior and senior staff at a Singapore hospital.

PURPOSE: To test the reliability of the Lens Opacities Classification System III (LOCS III) cataract grading between observers at different levels of ophthalmology experience. SETTING: Ophthalmology Department, National University Hospital, Singapore, Singapore. METHODS: In this comparative study, a non-ophthalmology trainee, a basic ophthalmology trainee, and an ophthalmology consultant graded cataracts in 28 patients preoperatively. The observers had a meeting to discuss their interpretations of the LOCS III manual to standardize the grading system and then graded 37 additional patients. RESULTS: There was a statistically significant increase in inter-observer agreement in all 3 LOCS III categories after standardization of the LOCS III system. The kappa values after standardization fell in the moderate (0.41 to 0.60) to substantial (0.61 to 0.80) range. There was no statistically significant relationship between the observer's experience and the kappa values. CONCLUSIONS: There was an increase in inter-observer agreement in all categories after standardization between operators.

Risk factors for early-onset corneal haze after photorefractive keratectomy in an Asian population: Outcomes from the Singapore Armed Forces Corneal Refractive Surgery Programme 2006 to 2013.

PURPOSE: To assess the incidence and risk factors for early corneal haze after myopic photorefractive keratectomy (PRK). SETTING: Tertiary eye center, Singapore. DESIGN: Retrospective case series. METHODS: The refractive results and corneal haze severity 3 months after PRK were analyzed. Eyes were categorized into 4 groups based on haze severity. Multivariate ordinal logistic regression analysis adjusting for age, ethnicity, sex, use of intraoperative mitomycin-C (MMC), preoperative sphere, and preoperative cylinder was performed. RESULTS: The study reviewed data from 177 patients (347 eyes) with a mean age of 22.6 years ± 4.1 (SD). The majority of the patients were Chinese (98.3%) and men (98.3%). The mean preoperative spherical equivalent (SE) was -3.34 ± 1.19 diopters (D). One hundred thirty-five eyes (38.9%) had PRK with MMC. Ten eyes (2.9%) had enhancement surgery. The overall efficacy index was 0.88 and the safety index was 1.07. At 3 months, 187 eyes (53.9%) had no haze, 76 eyes (21.9%) had a haze grade of more than 0 and less than 1, 76 eyes (21.9%) had a haze grade of 1 or more and less than 2, and 8 eyes (2.3%) had grade 2 haze. Higher degrees of myopia (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.13-1.63; P = .001) and astigmatism (OR, 1.56; 95% CI, 1.09-2.24; P = .014) were associated with increased severity of corneal haze, whereas older age (OR, 0.94; 95% CI, 0.88-0.99; P = .023) had a protective effect. CONCLUSION: Myopia and astigmatism were associated with increased severity of haze, and older age was protective against early corneal haze development after PRK in an Asian population. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.

Additive effect of unoprostone and latanoprost in patients with elevated intraocular pressure.

AIMS: To assess the additive effect of unoprostone and latanoprost in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT) METHODS: 32 patients with POAG or OHT were randomised to receive either latanoprost once daily or unoprostone twice daily for 4 weeks. After 4 weeks, all patients received both latanoprost and unoprostone for another 4 weeks. The IOP was measured at 9 am and 5 pm on the baseline, day 28, and day 56 visits, and at 9 am on day 14 and day 42 visits. The medications were given to the patients in an open label fashion. The observer was masked to the treatment given. The mean of the measurements was calculated. Safety parameters were also recorded. The additive effect of the medications was assessed by the reduction in intraocular pressure (IOP) when both medications were used, compared with when one medication was used. RESULTS: 28 patients completed both treatment periods and had IOP data available for evaluation. After 1 month of treatment, latanoprost significantly reduced IOP (mean by 6.1 (SEM 0.8) mm Hg (p<0.001) and unoprostone by 4.9 (1.0) mm Hg (p<0.001) from the baseline of 24.4 (0.6) mm Hg and 24.4 (1.1) mm Hg respectively (p = 0.18). When latanoprost once daily was given to patients treated with unoprostone, there was additional IOP lowering of 1.9 (0.6) mm Hg (p = 0.012). However, adding unoprostone to those being treated with latanoprost produced an IOP change of +0.4 (0.5) mm Hg (p = 0.42). Ocular symptoms and findings were mild and equally distributed between treatment groups, and after combined therapy. Hyperaemia and ocular irritation were the most frequently reported events. Over a third of patients experienced ocular irritation with the combination of medications. CONCLUSIONS: Latanoprost once daily causes additional IOP lowering in eyes which were being treated with unoprostone twice a day. However, there was no additional IOP lowering when unoprostone was added to eyes which were being treated with latanoprost. Both drugs were well tolerated together with few ocular adverse events.