Possible Modifying Effect of Hemoglobin A1c on Genetic Susceptibility to Severe Diabetic Retinopathy in Patients With Type 2 Diabetes.

Purpose: Glycemic control has been recognized as an important modifiable risk factor for diabetic retinopathy (DR). Whether hemoglobin A1c (HbA1c), as an indicator of glycemic control, could modify the genetic susceptibility to severe DR remains to be investigated. This study aimed to investigate whether HbA1c could modulate the genetic susceptibility to severe DR in Chinese patients with type 2 diabetes. Methods: A total of 3,093 Chinese individuals with type 2 diabetes were included in the cross-sectional case-control study: 1,051 with sight-threatening DR (STDR) and 2,042 without STDR. Sixty-nine top-ranked single nucleotide polymorphisms (SNPs) identified from previous genome-wide association studies were examined for their associations with STDR and proliferative DR as a subgroup analysis. SNPs showing suggestive associations with DR were examined in the stratified analysis by dichotomized HbA1c (<7% vs. ≥7%). An interaction analysis was performed by including an interaction term of SNP × HbA1c in the regression model. Results: Four SNPs showed suggestive associations with STDR. In the stratified analysis, patients with adequate glycemic control (HbA1c <7%) had a 42% lower risk of STDR for carrying each additional protective C allele of COL5A1 rs59126004 (P = 1.76 × 10-4; odds ratio, 0.58; 95% confidence interval, 0.44-0.77). rs59126004 demonstrated a significant interaction with dichotomized HbA1c on the risk of STDR (Pinteraction = 1.733 × 10-3). In the subgroup analysis for proliferative DR, the protective effect of rs59126004 was even more pronouncedly demonstrated (P = 8.35 × 10-5; odds ratio, 0.37; 95% confidence interval, 0.22-0.60) and it showed similar interactions with dichotomized HbA1c (Pinteraction = 1.729 × 10-3). Conclusions: Our data provided evidence for possible interactions between HbA1c and COL5A1 rs59126004 on the risk of severe DR. These findings may provide new insight into the pathophysiologic mechanism of DR.

Awareness of diabetic retinopathy and its association with attendance for systematic screening at the public primary care setting: a cross-sectional study in Hong Kong.

OBJECTIVE: To assess the association between awareness of diabetic retinopathy (DR) and actual attendance for DR screening. DESIGN: Cross-sectional study. SETTING: Two public general outpatient clinics. PARTICIPANTS: The subjects were people with diabetes mellitus (DM) who participated in a randomised controlled trial, set up in 2008, to test the impact of a copayment on attendance for DR screening. PRIMARY AND SECONDARY OUTCOME MEASURES: The subjects' awareness of DR was evaluated using a structured questionnaire conducted via a telephone interview. The attendance for screening was from the actual attendance data. Association between awareness and attendance for screening was determined using multivariate logistic regression model and was reported as ORs. RESULTS: A total of 2593 participants completed the questionnaire. A total of 42.9% (1113/2593) said they would worry if they had any vision loss and 79.6% (2063/2593) knew that DM could cause blindness. Only 17.5% (453/2593) knew that treatment was available for DR and 11.5% (297/2593) knew that early DR could be asymptomatic. The importance of having a regular eye examination was acknowledged by 75.7% (1964/2593), but 34% (881/2593) did not know how frequently their eyes should be examined. Worry about vision loss (OR=1.72, P<0.001), awareness of the importance of regular eye examination (OR=1.83, P=0.002) and awareness of the frequency of eye examinations ('every year' (OR=2.64, P<0.001) or 'every 6 months' (OR=3.27, P<0.001)) were the most significant factors associated with attendance. CONCLUSIONS: Deficits in knowledge of DR and screening were found among subjects with DM, and three awareness factors were associated with attendance for screening. These factors could be targeted for future interventions.

ONE-YEAR RESULTS OF HALF- VERSUS STANDARD-DOSE PHOTODYNAMIC THERAPY COMBINED WITH RANIBIZUMAB FOR POLYPOIDAL CHOROIDAL VASCULOPATHY.

PURPOSE: To explore the efficacy of half-dose verteporfin photodynamic therapy (hd-PDT) and standard-dose photodynamic therapy (sd-PDT), when combined with ranibizumab in the treatment of polypoidal choroidal vasculopathy. METHODS: Subjects were allocated to either the hd-PDT arm or the sd-PDT arm. All subjects received an injection of ranibizumab and PDT treatment (dosage according to allocation) at baseline. Subjects were followed up monthly for 12 months, and re-treatment were given at each visit if criteria were met. RESULTS: There were 26 subjects in the hd-PDT arm and 32 in the sd-PDT arm. Overall mean age was 69.3 ± 9.4 years. Baseline demographics and ocular features did not differ significantly between the two arms. Improvement in vision and reduction in central retinal thickness were similar between the two arms. When presenting, visual acuity was better than 20/50 (logarithm of the minimum angle of resolution 0.4), or when there were three or less polyps angiogram, those treated with hd-PDT tended to perform better than those treated with sd-PDT. CONCLUSION: In general, hd-PDT was able to produce similar results as sd-PDT. Subgroup analysis revealed superior results with hd-PDT when baseline vision was 20/50 or better, or when there were three or less polyps on indocyanine green angiography.

Health-related quality of life and health preference of Chinese patients with diabetes mellitus managed in primary care and secondary care setting: decrements associated with individual complication and number of complications.

BACKGROUND: Health-related quality of life (HRQoL) and health preference of patients with diabetes mellitus (DM) are essential in health economic evaluations but data on Chinese population is rare. This study aims to evaluate HRQoL and health preference of diabetic patients with different diabetic complications in Chinese population. METHODS: A cross-sectional study was conducted in 1275 patients with DM, including 518 subjects with various DM-related complications. HRQoL and health preference were estimated using SF-12 and SF-6D questionnaires, respectively. Disease status of DM and complications were identified from documented clinical diagnosis. Multivariable regression was used to investigate the effects of specific complications on HRQoL and health preference, adjusting for socio-demographic and clinical parameters. RESULTS: The presence of any diabetic complication was associated with lower physical component summary (-3.81 points, P < 0.01), and end-stage renal disease (ESRD) showed greatest reduction (-7.05 points, P < 0.01). Mental component summary and mental health (MH) scores were not decreased in any of the diabetic complications. The health preference score for diabetic subjects without complications was 0.882 (95% CI, 0.778 to 0.989). The reductions of health preference score were significant for stroke (-0.042, 95% CI -0.072 to -0.012), ESRD (-0.055, 95% CI -0.093 to -0.017), and sight-threatening diabetic retinopathy (STDR) (-0.043, 95% CI -0.075 to -0.010), while heart disease had an insignificant reduction (-0.017, 95% CI -0.042 to 0.008). CONCLUSIONS: The presence of any of the four major diabetic complications (heart disease, stroke, ESRD and STDR) was associated with lower HRQoL and health preference scores. Findings of this study facilitated the cost-effectiveness studies of alternative management strategies for prevention of diabetic complications in Chinese population.

Impact of Genetic Loci Identified in Genome-Wide Association Studies on Diabetic Retinopathy in Chinese Patients With Type 2 Diabetes.

PURPOSE: Diabetic retinopathy (DR) is a common microvascular complication of type 2 diabetes (T2DM). Genome-wide association studies (GWAS) had identified novel DR-susceptibility genetic variants in various populations. We examined the associations of these DR-associated single nucleotide polymorphisms (SNPs) with severe DR in a Chinese T2DM cohort. METHODS: Cross-sectional case-control studies on sight-threatening DR (STDR) and proliferative DR (PDR) were performed. We genotyped 38 SNPs showing top association signals with DR in previous GWAS in 567 STDR cases, including 309 with PDR and 1490 non-DR controls. Multiple logistic regression models with adjustment for conventional risk factors, including age, sex, duration of diabetes, and presence of hypertension, were employed. RESULTS: The strongest association was found at INSR rs2115386, an intronic SNP of INSR: Padjusted = 9.13 × 10-4 (odds ratio [OR],1.28; 95% confidence interval [95%CI], 1.11-1.48) for STDR, and Padjusted= 1.12 × 10-4 (OR [95%CI],1.44 [1.20-1.74]) for PDR. rs599019 located downstream of COLEC12 (Padjusted = 0.019; OR [95%CI],1.19 [1.03-1.38]) and rs4462262 located at an intergenic region between ZWINT and MRPS35P3 (Padjusted = 0.041; OR [95%CI],1.38[1.01-1.89]) also were significantly associated with STDR, but not with PDR alone. On the other hand, MYT1L-LOC729897 rs10199521 (Padjusted = 0.022; OR [95%CI],1.25 [1.03-1.51]) and API5 rs899036 (Padjusted = 0.049; OR [95%CI],1.36 [1.00-1.85]) showed significant independent associations only with PDR. Similar results were obtained when hemoglobin A1c also was included in the adjustment models. CONCLUSIONS: We demonstrated the significant and independent associations of several GWAS-identified SNPs with DR in Chinese T2DM patients with severe DR. The findings on INSR rs2115386 are supportive of the role of insulin resistance, or the compensatory hyperinsulinemia, in the pathogenesis of DR.

Detection of preperimetric glaucoma using Bruch membrane opening, neural canal and posterior pole asymmetry analysis of optical coherence tomography.

We analysed retinal nerve fibre layer (RNFL) defects in eyes with normal circumpapillary RNFL (cpRNFL) thickness using posterior pole asymmetry analysis (PPAA) and investigated the parameters of Bruch membrane opening (BMO) and neural canals using enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT). A total of 112 preperimetric glaucomatous eyes of 92 patients were examined to obtain cpRNFL thickness using SD-OCT. Posterior pole asymmetry analysis (PPAA) and central cross-sectional images of the optic nerve head (ONH) were obtained using EDI-SDOCT. Minimal and horizontal distances between the BMO and ONH surfaces (BMOM, BMOH) and the terminal of retinal pigment epithelium (RPE) and ONH surfaces (RPEM, RPEH) were measured. The distribution of the absolute black cells in PPAA was more concentrated in eyes with "U"-shaped neural canals (p < 0.0001). The area under the receiver operating characteristic curve of the ratio of RPEM to RPEH (RPE-R, 0.771 ± 0.08) was significantly larger than the ratio of BMOM to BMOH (BMO-R, 0.719 ± 0.009) for PPAA results. A U-shaped neural canal, lower ratio of RPEM to RPEH, and lower ratio of BMOM to BMOH were considered early indicators of RNFL defects in preperimetric glaucomatous eyes with normal cpRNFL.

Systematic screening for diabetic retinopathy (DR) in Hong Kong: prevalence of DR and visual impairment among diabetic population.

PURPOSE: To determine the prevalence of diabetic retinopathy (DR), sight threatening DR (STDR), visual impairment and other eye diseases in a systematic DR screening programme among primary care Chinese patients with diabetes mellitus (DM) in Hong Kong. METHODS: Screening for DR was provided to all subjects with DM in public primary care using digital fundus photography according to the English national screening programme. STDR was defined as preproliferative DR (R2), proliferative DR (R3) and/or maculopathy (M1). The presence of other eye diseases was noted. Visual impairment was classified as none (visual acuity in the better eye of 6/18 or better), mild (6/18 to >6/60) and severe (6/60 or worse). RESULTS: Of 174 532 subjects screened, most had never been screened before. The prevalence of DR was 39.0% (95% CI 38.8% to 39.2%) and STDR 9.8% (95% CI 9.7% to 9.9%). The most common DR status was R1 (35.7%), followed by M1 (8.6%), R2 (3.0%) and R3 (0.3%). The prevalence of mild and severe visual impairment was 4.2% and 1.3%, respectively. Subjects with STDR had a higher prevalence (9.8%) of visual impairment than those without (3.5%). CONCLUSIONS: DR was prevalent in this population and one in 10 had STDR. This suggests the need for systematic screening to ensure timely referral to an ophthalmologist for monitoring and/or treatment.

Detection of Glaucoma and Its Association With Diabetic Retinopathy in a Diabetic Retinopathy Screening Program.

PURPOSE: To determine the type of glaucoma in subjects with diabetes mellitus detected during a diabetic retinopathy screening program and to determine any association between diabetic retinopathy (DR) and glaucoma. MATERIALS AND METHODS: This is a population-based prospective cross-sectional study, in which subjects with diabetes mellitus underwent screening for DR in a primary care outpatient clinic. Digital fundus photographs were taken and graded for presence/absence and severity of DR. During this grading, those fundus photographs showing increased cup-to-disc ratio (CDR) (≥0.6) were identified and these patients were referred to the specialist ophthalmology clinic for detailed examination. The presence of glaucoma was established based on CDR and abnormal visual field (VF) defects according to Hodapp-Parrish-Anderson's criteria. An elevation of intraocular pressure was not required for the diagnosis of glaucoma. The patients said to have definite glaucoma were those with vertical CDR>/=0.6, glaucomatous defects on VF examination, or retinal nerve fiber thinning if VF was unreliable. RESULTS: Of the 2182 subjects who underwent screening, 81 subjects (3.7%) had increased CDR and 40 subjects (1.8%) had confirmed glaucoma. Normal-tension variant of primary open-angle glaucoma was the most prevalent type (1.2%) We did not find any evidence that DR is a risk factor for glaucoma [odds ratio for DR vs. no DR=1.22 (95% confidence interval, 0.59-2.51)]. CONCLUSION: The overall prevalence of glaucoma in this diabetic population, based on finding increased cupping of optic disc in a teleretinal screening program was 1.8% (95% confidence interval, 1.0-3.0).

Cost-Effectiveness of Screening for Intermediate Age-Related Macular Degeneration during Diabetic Retinopathy Screening.

PURPOSE: To determine whether screening for age-related macular degeneration (AMD) during a diabetic retinopathy (DR) screening program would be cost effective in Hong Kong. DESIGN: We compared and evaluated the impacts of screening, grading, and vitamin treatment for intermediate AMD compared with no screening using a Markov model. It was based on the natural history of AMD in a cohort with a mean age of 62 years, followed up until 100 years of age or death. PARTICIPANTS: Subjects attending a DR screening program were recruited. METHOD: A cost-effectiveness analysis was undertaken from a public provider perspective. It included grading for AMD using the photographs obtained for DR screening and treatment with vitamin therapy for those with intermediate AMD. The measures of effectiveness were obtained largely from a local study, but the transition probabilities and utility values were from overseas data. Costs were all from local sources. The main assumptions and estimates were tested in sensitivity analyses. MAIN OUTCOME MEASURES: The outcome was cost per quality-adjusted life year (QALY) gained. Both costs and benefits were discounted at 3%. All costs are reported in United States dollars ($). RESULTS: The cost per QALY gained through screening for AMD and vitamin treatment for appropriate cases was $12,712 after discounting. This would be considered highly cost effective based on the World Health Organization's threshold of willingness to pay (WTP) for a QALY, that is, less than the annual per capita gross domestic product of $29,889. Because of uncertainty regarding the utility value for those with advanced AMD, we also tested an extreme, conservative value for utility under which screening remained cost effective. One-way sensitivity analyses revealed that, besides utility values, the cost per QALY was most sensitive to the progression rate from intermediate to advanced AMD. The cost-effectiveness acceptability curve showed a WTP for a QALY of $29,000 or more has a more than 86% probability of being cost effective compared with no screening. CONCLUSIONS: Our analysis demonstrated that AMD screening carried out simultaneously with DR screening for patients with diabetes would be cost effective in a Hong Kong public healthcare setting.

1-year results of combined half-dose photodynamic therapy and ranibizumab for polypoidal choroidal vasculopathy.

BACKGROUND: To evaluate the efficacy and safety of half-dose photodynamic therapy (PDT combined with ranibizumab for polypoidal choroidal vasculopathy (PCV). PCV is commonly treated with a combination of anti-vascular endothelial growth factor and standard-dose photodynamic therapy (PDT). Choroidal ischemia and visual loss can be resulted from the standard-dose PDT. Half-dose PDT has proved to produce similar results and safety profile in treating central serous chorioretinopathy. Half-dose PDT may offer an alternative for PCV cases where the damage to choroidal vasculature maybe less. Here, we report the efficacy of treating PCV cases with combination of ranibizumab and half-dose PDT. METHODS: In this prospective, non-comparative, interventional case series, 19 treatment-naive eyes were treated with combined half-dose PDT and ranibizumab. All subjects were followed up for 12 months with measurement of best-corrected visual acuity (BCVA), central foveal thickness (CFT) by optical coherence tomography. Indocyanine green angiogram (ICG) was performed every 3-monthly, and subjects assessed in terms of polyp regression rates, changes in vision and central foveal thickness, need to repeat half-dose PDT. Subgroup analysis was performed based on ICG features. RESULTS: The mean logMAR BCVA improved from 0.64 at baseline to 0.41 at 12 months. The mean CFT improved from 459.6 mum at baseline to 384.2 mum at 12 months. The difference between baseline BCVA and CFT and that at 12 months were statistically significant (both P = 0.03). Polyp regression rate after one half-dose PDT was 42.1 %. This was 61.5 % in the polyp-only group, while that in the branching-vascular-network (BVN) group was 0 % (P = < 0.01). CONCLUSION: Half-dose PDT combined with intravitreal ranibizumab was able to induce high polyp regression rate in PCV cases that had one single polyp.

The Correlation of Retinal Nerve Fiber Layer Thickness With Blood Pressure in a Chinese Hypertensive Population.

To investigate the association between retinal nerve fiber layer (RNFL) thickness and blood pressure (BP) in subjects with systemic hypertension. Subjects with systemic hypertension on anti-hypertensive medications were screened by fundus photography and referred for glaucoma work-up if there was enlarged vertical cup-to-disc (VCDR) ratio ≥0.6, VCDR asymmetry ≥0.2, or optic disc hemorrhage. Workup included a complete ophthalmological examination, Humphrey visual field test, and RNFL thickness measurement by optical coherence tomography. The intraocular pressure (IOP) and RNFL thicknesses (global and quadrant) were averaged from both eyes and the means were correlated with: the systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) using Pearson correlation. Among 4000 screened hypertensive subjects, 133 were referred for glaucoma workup and 110 completed the workup. Of the 4000 screened subjects, 1.3% had glaucoma (0.9% had normal tension glaucoma [NTG], 0.2% had primary open angle glaucoma, and 0.2% had primary angle closure glaucoma), whereas 0.3% were NTG suspects. The SBP was negatively correlated with the mean superior RNFL thickness (P = 0.01). The DBP was negatively correlated with the mean global (P = 0.03), superior (P = 0.02), and nasal (P = 0.003) RNFL thickness. The MAP was negatively correlated with the mean global (P = 0.01), superior (P = 0.002), and nasal (P = 0.004) RNFL thickness while positively correlated with the mean IOP (P = 0.02). In medically treated hypertensive subjects, glaucoma was present in 1.3%, with NTG being most prevalent. MAP control may help with IOP lowering and RNFL preservation, although future prospective studies will be needed.

Protocol-driven adjustment of ocular hypotensive medication in patients at low risk of conversion to glaucoma.

AIM: To investigate the safety and potential savings of decreasing medication use in low-risk patients with ocular hypertension (OH). METHODS: Patients with OH receiving pressure-lowering medication identified by medical record review at a university hospital underwent examination by a glaucoma specialist with assessment of visual field (VF), vertical cup-to-disc ratio (vCDR), central corneal thickness and intraocular pressure (IOP). Subjects with estimated 5-year risk of glaucoma conversion <15% were asked to discontinue ≥1 medication, IOP was remeasured 1 month later and risk was re-evaluated at 1 year. RESULTS: Among 212 eyes of 126 patients, 44 (20.8%) had 5-year risk >15% and 14 (6.6%) had unreliable baseline VF. At 1 month, 15 patients (29 eyes, 13.7%) defaulted follow-up or refused to discontinue medication and 11 eyes (5.2%) had risk >15%. The remaining 69 patients (107 eyes, 50.7%) successfully discontinued 141 medications and completed 1-year follow-up. Mean IOP (20.5±2.65 mm Hg vs 20.3±3.40, p=0.397) did not change, though mean VF pattern SD (1.58±0.41 dB vs 1.75±0.56 dB, p=0.001) and glaucoma conversion risk (7.31±3.74% vs 8.76±6.28%, p=0.001) increased at 1 year. Mean defect decreased (-1.42±1.60 vs -1.07±1.52, p=0.022). One eye (0.47%) developed a repeatable VF defect and 13 eyes (6.1%) had 5-year risk >15% at 1 year. The total 1-year cost of medications saved was US$4596. CONCLUSIONS: Nearly half (43.9%) of low-risk OH eyes in this setting could safely reduce medications over 1 year, realising substantial savings.

Prospective study on the efficacy of treating normal tension glaucoma with a single session of selective laser trabeculoplasty.

PURPOSE: The purpose of this study was to investigate the efficacy of selective laser trabeculoplasty (SLT) in the treatment of normal tension glaucoma (NTG). METHODS: This prospective cohort study recruited consecutive cases of NTG on antiglaucoma medication. Cases were excluded for previous glaucoma surgery or laser. All patients underwent a 1-month washout of medication followed by a mean baseline intraocular pressure (IOP) measured at 9 AM, 1 PM, and 5 PM. A 30% reduction from baseline was set as the target IOP. A single session of SLT was performed to 360 degrees of the trabecular meshwork. IOP phasing was repeated at 1 month after SLT and medication was resumed to achieve the target IOP. Patients were followed up to 6 months after SLT. RESULTS: In 83 eyes of 46 subjects, the mean prestudy IOP was 14.2 ± 3.1 mm Hg when on 1.5 ± 0.9 antiglaucoma medication. The mean baseline IOP without medication was 16.1 ± 2.2 mm Hg. The mean SLT shots applied was 187.8 ± 27.5 using a mean energy of 1.0 ± 0.07 mJ. At 1-month post-SLT, the IOP was 12.7 ± 2.0 mm Hg (21.6% IOP reduction) from baseline without medication (P<0.05). The 6-month IOP was 11.4 ± 1.6 mm Hg when on 1.1± 1.0 medications, representing a 19.7% reduction from prestudy IOP, a 29.6% reduction from baseline IOP, and a 26.7% reduction in antiglaucoma medication (all P< 0.05). A higher baseline IOP was correlated with greater IOP reduction with SLT (r=0.3, P=0.009). CONCLUSIONS: A single session of SLT for NTG achieved an additional 20% reduction in IOP with 27% less medication at 6 months compared with prestudy levels while maintaining a 30% reduction from baseline IOP.

Use digital subtraction images of blue-light and near-infrared autofluorescence for the assessment of irregular foveal contour.

The aims of this study are to generate subtraction images of blue-light autofluorescence (BL-AF) and near-infrared autofluorescence (NIR-AF) from normal eyes, eyes with full thickness macular holes, and eyes with irregular foveal contour, and to compare their autofluorescence patterns. This retrospective study included 44 normal eyes of 22 health individuals, 32 eyes with full thickness macular holes of 32 patients, and 36 eyes with irregular foveal contour of 36 patients. BL-AF and NIR-AF were obtained from all patients and used to generate subtraction images using the Image J software. The decreased signal of central patch was recorded. The central foveal thickness (CFT) and outer nucleus layer (ONL) thickness of fovea were measured to calculate the ONL thickness/CFT ratio. The subtraction images showed regularly increased signal in the central macula of all normal eyes. In contrast, decreased signal of central patch was detected in all full thickness macular holes eyes and 26 out of 36 eyes with irregular foveal contour. No significant difference of the ONL thickness/CFT ratio (F = 2.32, P = 0.113) was observed between normal and irregular foveal contour eyes with or without decreased signal of central patch. Both regularly increased signal and decreased signal of central patch were detected in the eyes with irregular foveal contour. Our results suggest that subtraction images are useful for the assessment of certain macular conditions by providing supplementary information to the green-light autofluorescence and BL-AF.

The incidental findings of age-related macular degeneration during diabetic retinopathy screening.

BACKGROUND: The purpose of this study was to determine the reliability of detecting age-related macular degeneration (AMD) during screening for diabetic retinopathy (DR). METHODS: This prospective study included 2,003 subjects with diabetes mellitus who underwent photographic screening for DR. The reliability of detecting AMD lesions was tested by interobserver and intraobserver agreement, and the sensitivity and specificity of diagnosing AMD at different grades of severity were tested using the consensus grading of a group as the reference standard. RESULTS: DR affected 24.7% of the subjects. The age-standardized prevalence of early AMD was 17.9%, and late AMD was 0.1%. The interobserver and intraobserver agreement for grading AMD was substantial (k = 0.72 and 0.71 respectively, p < 0.001). It was equally good in those with different severities of DR. There was also no difference in sensitivity and specificity of detecting AMD in those with different levels of DR (sensitivity 62-68% and specificity 97-98%). CONCLUSION: Intermediate- and high-risk AMD that warrant treatment with zinc and anti-oxidant supplements could be reliably detected during screening for diabetic retinopathy.

Screening for diabetic retinopathy with or without a copayment in a randomized controlled trial: influence of the inverse care law.

OBJECTIVE: To examine whether the inverse care law operates in a screening program for diabetic retinopathy (DR) based on fee for service in Hong Kong. DESIGN: Randomized controlled trial. PARTICIPANTS: All those with type 1 or 2 diabetes from 2 clinics were recruited. INTERVENTION: Diabetic retinopathy screening with a small copayment versus free access in a publicly funded family medicine service. MAIN OUTCOME MEASURES: Uptake of screening and severity of DR detected. Association between these outcome variables and independent variables were determined using multivariate logistic regression models and reported as odds ratios (ORs). RESULTS: After randomization, 1387 subjects in the free group and 1379 subjects in the pay group were eligible for screening, and 94.9% (1316/1387) and 92.6% (1277/1379), respectively, agreed to participate in the study. The offer of screening was accepted by 94.8% (1247/1316) in the free group and 91.2% (1164/1277) in the pay group, and the final uptake ratios were 88.5% (1165/1316) and 82.4% (1052/1277), respectively (Pearson chi = 19.74, P<0.001). Being in the pay group was associated with a lower uptake of screening than being in the free group (OR, 0.59; confidence interval [CI], 0.47-0.74) and a lower detection rate of DR (OR, 0.73; CI, 0.60-0.90) after adjustment for potential confounding factors. Subjects with higher socioeconomic status were more likely to attend screening and had a lower prevalence of DR detected. CONCLUSIONS: The inverse care law seems to operate in a preventive intervention when a relatively small copayment is applied. There is a case for making effective preventive services free of charge. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Detection of glaucoma in a cohort of chinese subjects with systemic hypertension.

Purpose. To determine the presence and type of glaucoma in a cohort of adult Chinese subjects with systemic hypertension. Methods. This prospective cohort study included 200 hypertensive Chinese adults aged >40 years old who underwent screening via frequency doubling technology (FDT) perimetry and intraocular pressure (IOP) measurement by noncontact tonometry (NCT) in a general outpatient clinic. Those with IOP > 21 mmHg and/or visual field (VF) defects on FDT were referred for complete ophthalmological examination. The diagnosis of glaucoma was based on an abnormal VF on Humphrey Field Analyzer (HFA) by Hodapp-Parrish-Anderson's criteria and an increased vertical cup-disc ratio (VCDR). Results. The mean age of the subjects was 64.66 ± 9.47 years, and the male:female ratio was 92 : 108. All patients were hypertensive with a mean blood pressure (BP) of 131.1 ± 15.1/76.6 ± 11.1 mmHg whilst on systemic antihypertensive medication. Of the 111 patients that had an abnormal initial screening, 14 (7.9%) were confirmed to have glaucoma with the highest prevalence of normal tension glaucoma (NTG) (6.2%), followed by primary angle closure glaucoma (PACG) (1.1%) and primary open angle glaucoma (POAG) (0.5%). The positive predictive value of FDT perimetry was 71%. Conclusion. Nearly 8% of the adults with systemic hypertension had glaucoma, and NTG was the most prevalent type.

Medication-induced acute angle closure attack.

OBJECTIVE: To review acute angle closure attacks induced by local and systemic medications. DATA SOURCES: PubMed literature searches up to August 2011. STUDY SELECTION: The following key words were used for the search: "drug", "iatrogenic", "acute angle closure glaucoma". DATA EXTRACTION: A total of 86 articles were retrieved using the key words. Only those concerning acute angle closure attack triggered by local or systemic drug administration were included. For articles on the same or related topics, those published at later or more recent dates were selected. As a result, 44 articles were included and formed the basis of this review. DATA SYNTHESIS: An acute attack of angle closure can be triggered by dilatation of the pupil, by anatomical changes in the ciliary body and iris, or by movement of the iris-lens diaphragm. Local and systemic medications that cause these changes have the potential to precipitate an attack of acute angle closure. The risk is higher in subjects who are predisposed to the development of angle closure. Many pharmaceutical agents including ophthalmic eyedrops and systemic drugs prescribed by general practitioners and various specialists (in psychiatry, otorhinolaryngology, ophthalmology, medicine, and anaesthesia) can precipitate an acute angle closure attack. The medications include: anti-histamines, anti-epileptics, antiparkinsonian agents, antispasmolytic drugs, mydriatic agents, sympathetic agents, and botulinum toxin. CONCLUSION: Since acute angle closure attack is a potentially blinding eye disease, it is extremely important to be vigilant and aware of ophthalmic and systemic medications that can lead to such attacks in predisposed subjects and to diagnose the condition when it occurs.