Does neuronal damage precede vascular damage in subjects with type 2 diabetes mellitus and having no clinical diabetic retinopathy?

AIM: To investigate the occurrence of neuronal damage, as the earliest change occurring, before the clinical evidence of diabetic retinopathy. METHODS: 70 eyes of subjects with type 2 diabetes mellitus and with no evidence of diabetic retinopathy (cases) and 40 eyes of subjects with no diabetes mellitus (controls) were studied using spectral-domain OCT and microperimetry. The influence of age and gender on the outcome measures was also analyzed. RESULTS: Age- and gender-matched subjects showed a decreased mean retinal nerve fiber layer thickness in cases when compared to the controls (27 vs. 33 µm; p=0.018). Among the cases, subjects between 40 and 45 years of age showed a reduced mean central foveal thickness (175.1 vs. 198.1 µm; p=0.05), mean retinal thickness in the central 6-mm fundus (260.5 vs. 275.3 µm; p=0.006) and mean retinal nerve fiber layer thickness (29 vs. 39 µm; p=0.036) when compared to the controls. However, no differences were noted in the microperimetry outcomes in cases when compared to the controls. The duration of diabetes and the glycemic control did not show any significant changes on the outcome measures in cases, except for a significantly lower mean retinal sensitivity in diabetics with glycosylated hemoglobin values<7% as compared to those with glycosylated hemoglobin≥7% (14.1±2.9 vs. 15.4±1.7 dB; p=0.027). CONCLUSION: The results suggest that there is some evidence of early neuronal damage particularly on spectral-domain OCT, before the clinical evidence of diabetic retinopathy, in subjects with type 2 diabetes mellitus.

Is prevalence of retinopathy related to the age of onset of diabetes? Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Report No. 5.

AIM: To compare the prevalence of diabetic retinopathy (DR) and risk factors in patients with a known onset of diabetes before 40 years and after 40 years of age. METHODS: This is a population-based study for which 1,414 diabetics were recruited. The fundi were photographed using 45-degree 4-field stereoscopic digital photography. The diagnosis of DR was based on Klein's classification of the Early Treatment Diabetic Retinopathy Study scales. RESULTS: The prevalence of DR was 33.3% (95% confidence interval, CI: 26.6-39.9) in known onset of diabetes (≤ 40 years) compared to 15.6% (95% CI: 13.6-17.6) in those with late onset (> 40 years; p < 0.0001). In the group with age of known onset of diabetes ≤ 40 years, the risk factors, associated with any DR, were poor glycemic control (odds ratio, OR: 1.36 for every g% increase in glycosylated hemoglobin), insulin use (OR: 4.21), increasing known duration of diabetes (OR: 1.10 for increase of every year in known duration of diabetes) and presence of macroalbuminuria (OR: 13.39). In the late onset of diabetes group, besides the above-mentioned risk factors, the presence of microalbuminuria (OR: 2.08), male gender (OR: 1.67), presence of anemia (OR: 1.89) and increased systolic blood pressure (OR: 1.01) were the risk factors for DR. CONCLUSION: The prevalence of DR was almost twice more in those subjects who developed diabetes before the age of 40 years than those who developed it later.

The prevalence and risk factors for age-related macular degeneration in rural-urban India, Sankara Nethralaya Rural-Urban Age-related Macular degeneration study, Report No. 1.

PurposeTo report the age- and gender-adjusted prevalence rates of early and late age-related maculopathy (ARM) and associated risk factors in rural and urban Indian population.MethodsA population-based cross-sectional study was carried out in South India between 2009 and 2011. Of the 6617 subjects ≥60 years enumerated ones, 5495 (83.04%) participated in the eye examination. A detailed history including data on demographic, socioeconomic, and ocular history was obtained. Participants underwent detailed ophthalmic evaluation including 30° 3-field photograph as per Age-Related Eye Disease Study protocol. The ARM was graded according to the International ARM Epidemiological Study Group.ResultsAge- and gender-adjusted prevalence of early ARM was 20.91% (20.86-20.94) in the rural population and 16.37% (16.32-16.42) in the urban population. Similarly, the prevalence of late ARM was 2.26% (2.24-2.29) and 2.32% (2.29-2.34) in the rural and urban population, respectively. In both rural and urban populations, risk factors that were related to both early and late ARM were age, per year increase (OR, range 1.00-1.08); middle socioeconomic status (OR, range 1.05-1.83); and smokeless tobacco (OR, range 1.11-2.21). Protective factor in both was the presence of diabetes mellitus in all ARM (OR, range 0.34-0.83). Risk factors, only in the rural arm, were female gender (OR, range 1.06-1.64), past smoker (OR, 1.14), and serum low-density lipoprotein cholesterol level (OR, 1.03).ConclusionsThe study reports smokessless tobacco as a risk factor for both early and late ARM and identified a higher prevalence of early ARM in the rural population compared with urban population.

Time Trends in Breast Cancer Among Indian Women Population: An Analysis of Population Based Cancer Registry Data.

BACKGROUND: The trends observed in cancer breast among Indian women are an indication of effect of changing lifestyle in population. To draw an appropriate inference regarding the trends of a particular type of cancer in a country, it is imperative to glance at the reliable data collected by Population Based Cancer Registries over a period of time. OBJECTIVE: To give an insight of changing trends of breast cancer which have taken place over a period of time among women in Cancer Registries of India. Breast Cancer trends for invasive breast cancer in women in Indian Registries have varied during the selected period. Occurrence of breast cancers has also shown geographical variation in India. MATERIALS AND METHODS: This data was collected by means of a 'Standard Core Proforma' designed by NCRP conforming to the data fields as suggested by International norms. The Proforma was filled by trained Registry workers based on interview/ hospital medical records/ supplementing data by inputs from treating surgeons/radiation oncologists/involved physicians/pathologists. The contents of the Proforma are entered into specifically created software and transmitted electronically to the coordinating center at Bangalore. The registries contributing to more number of years of data are called as older registries, while other recently established registries are called newer registries. RESULTS: While there has been an increase recorded in breast cancer in most of the registries, some of them have recorded an insignificant increase. Comparison of Age Adjusted Rates (AARs) among Indian Registries has been carried out after which trends observed in populations covered by Indian Registries are depicted. A variation in broad age groups of females and the proneness of females developing breast cancer over the period 1982 to 2010 has been shown. Comparisons of Indian registries with International counterparts have also been carried out. CONCLUSIONS: There are marked changes in incidence rates of cancer breast which have occurred in respective registries in a developing country like India. A steady increase in AARs in most of the registries of India including the newly established registries is indicative of the fact that cancer breast poses a threat to women in India.

Macular pigment optical density in wet age-related macular degeneration among Indians.

PURPOSE: To estimate the value of macular pigment optical density (MPOD) in adult south Indian population with wet age-related macular degeneration (AMD). METHODS: A total of 33 patients with wet AMD and 29 age-matched controls >50 years of age underwent MPOD measurement with the macular densitometer. The patients were also tested for their dietary intake of carotenoids, smoking history, and lifetime UV exposure. RESULTS: The mean MPOD values in the Indian population with wet AMD was 0.23 (95% CI: 0.18-0.29) vs control was 0.43 (95% CI: 0.37-0.49), P<0.0001, at 0.5° eccentricity. Ex-smokers had a lower MPOD than non-smokers (0.16 (0.09-0.23) vs 0.28 (0.22-0.34), P=0.026) and the lowest level of carotenoids intake had 48% lower MPOD than the highest level (0.14 (0.08-0.21) vs 0.33 (0.24-0.43), P=0.012). There was no significant age-related decline or gender variation in MPOD. CONCLUSION: This study establishes the MPOD in adult Indian population with wet AMD, with a lack of macular pigment in association with wet AMD.

Comparison between Humphrey Field Analyzer and Micro Perimeter 1 in normal and glaucoma subjects.

PURPOSE: To determine the correlation between fundus perimetry with Micro Perimeter 1 (MP1) and conventional automated static threshold perimetry using the Humphrey Field Analyzer (HFA) in healthy individuals and in subjects with glaucoma. MATERIALS AND METHODS: In this study, we enrolled 45 eyes with glaucoma and 21 eyes of age-matched, healthy individuals. All subjects underwent complete ophthalmic examination. Differential light sensitivity was measured at 21 corresponding points in a rectangular test grid in both MP1 and HFA. Similar examination settings were used with Goldmann III stimulus, stimulus presentation time of 200 ms, and white background illumination (1.27 cd/m(2)). Statistical analysis was done with the SPSS 14 using linear regression and independent t-test. RESULTS: The mean light thresholds of 21 matching points in control group with MP1 and HFA were 14.97 ± 2.64 dB and 30.90 ± 2.08 dB, respectively. In subjects with glaucoma, the mean values were MP1: 11.73 ± 4.36 dB and HFA: 27.96 ± 5.41 dB. Mean difference of light thresholds among the two instruments was 15.86 ± 3.25 dB in normal subjects (P < 0.001) and 16.22 ± 2.77 dB in glaucoma subjects (P < 0.001). Pearson correlation analysis of the HFA and MP1 results for each test point location in both cases and control subjects showed significant positive correlation (controls, r = 0.439, P = 0.047; glaucoma subjects, r = 0.812, P < 0.001). There was no difference between nasal and temporal points but a slight vertical asymmetry was observed with MP1. CONCLUSION: There are significant and reproducible differences in the differential light threshold in MP1 and HFA in both normal and glaucoma subjects. We found a correction factor of 17.271 for comparison of MP1 with HFA. MP1 appeared to be more sensitive in predicting loss in glaucoma.

Influence of glycosylated hemoglobin on sight-threatening diabetic retinopathy: a population-based study.

AIM: To evaluate the role of glycosylated hemoglobin (HbA1c) on the occurrence of sight-threatening diabetic retinopathy (STDR) in urban Chennai, Tamil Nadu, India. METHODS: A total of 5999 individuals were enumerated from the Chennai metropolis. Of these, 1414 subjects with diabetes were included for data analysis in the study. STDR or non-STDR groups were classified based on the fundus photographs. HbA1c was measured (Bio-Rad DiaSTAT™ HbA1c Reagent Kit) by the liquid chromatography technique. RESULTS: A statistically significant difference (p < 0.05) was noted in the duration of diabetes, gender, body mass index, HbA1c, micro- and macro-albuminuria between both non-STDR and STDR groups as compared to the no-diabetic retinopathy (DR) group. On multivariate analysis, HbA1c (non-STDR: odd's ratio OR = 1.23; 95% confidence interval CI = 1.15-1.32; p < 0.0001; STDR: OR = 1.31 95% CI = 1.14-1.52; p < 0.0001) was found to be significantly associated with non-STDR and STDR when compared with the no-DR group. The Receiver Operating Characteristic analysis showed that the cut-off value of 8.0 had 75.6% sensitivity and 58.2% specificity with 64.9% maximum area under the curve. CONCLUSION: HbA1c value >8.0% was significantly related with STDR. In a screening programme, the cut-off value of HbA1c >8.0% provided a maximum yield of STDR.

Is neuronal dysfunction an early sign of diabetic retinopathy? Microperimetry and spectral domain optical coherence tomography (SD-OCT) study in individuals with diabetes, but no diabetic retinopathy.

PURPOSE: To elucidate changes in the neurosensory retina in the macular area, using spectral domain OCT and correlate with functional loss on fundus-related microperimetry, in patients with diabetes and no diabetic retinopathy compared with age-matched healthy volunteers. METHODS: This was a prospective study enrolling 39 patients in each group. All patients underwent comprehensive dilated eye examination. The foveal thickness and the photoreceptor layer thickness at the foveal centre were measured using spectral domain OCT, and the mean retinal sensitivity of central 20 degrees was measured using microperimetry. RESULTS: The mean age of the patients with diabetes was 50.92+/-4.75 years, and of controls, 49.87+/-5.50 years. SD-OCT measured photoreceptor layer thickness (PLT) to be 61.62+/-4.48 microm in cases, and 68.79+/-7.84 microm in controls (P<0.0001); foveal thickness (FT) was 168.64+/-16.46 microm in cases and 177.74+/-14.58 microm in controls (P=0.012). The mean retinal sensitivity (MRS) of the central 20 degrees, measured on microperimetry was 15.74+/-3.74 db in cases and 17.70+/-1.5 db in controls (P<0.003). In cases compared with controls (aged under 50 years) statistically significant differences were noted in all the three outcome variables: FT, P=0.030; PLT, P=0.015; and MRS, P=0.020. The duration of diabetes influenced only the PLT (P=0.017). Statistical analysis was performed with Student's t-test and chi2 test. CONCLUSION: Neuronal damage was observed in those eyes that did not have clinical evidence of diabetic retinopathy.