Relationship Between Cooking Fuel and Lens Opacities in South India: A 15-Year Prospective Cohort Study.

PURPOSE: To determine whether exposure to unclean cooking fuels was associated with subsequent cataract progression as reported in previous cross-sectional studies. DESIGN: Prospective cohort study. METHODS: This is a secondary observational analysis of the community-based Antioxidants in Prevention of Cataracts trial (ClinicalTrials.gov ID NCT01664819). The exposure of interest was cooking fuel type, measured at baseline. Main outcome measures were baseline cataract severity and self-reported cataract surgery at a 15-year visit. RESULTS: Baseline and 15-year follow-up data were available for 798 and 579 participants, respectively. Wood or kerosene was used by 711 of 798 (89.1%) baseline participants, including 539 of 579 (93.1%) participants with complete follow-up. Cooking fuel type was not associated with cataract severity at baseline (P = .443). Of 8334 person-years of follow-up, 90 cataract surgeries were observed over 15 years (1.08 surgeries per 100 person-years; 95% CI = 0.87-1.32). Use of wood or kerosene was not associated with 15-year incidence of cataract surgery relative to use of propane (adjusted P = .154). Cataract surgery was more common in older individuals (HR = 1.1 per year, 95% CI = 1.1-1.2, P < .001), those with baseline myopia (HR = 2.1, 95% CI = 1.2-3.5, P = .009), and women (HR = 3.5, 95% CI = 1.2-10.1, P = .019). CONCLUSIONS: This study found no association between unclean cooking fuels and cataract progression over a 15-year period. No other modifiable risk factors were associated with incident self-reported cataract surgery.

Ultrastructural study of the kidney in the coelacanth Latimeria chalumnae (Rhipidistia: Coelacanthini).

The morphology of the nephrons of the coelacanth Latimeria chalumnae was investigated by electron microscopy. Each nephron is composed of a large renal corpuscle with well vascularized glomerulus, ciliated neck segment, proximal tubule divided into first and second proximal segments, ciliated intermediate segment, distal tubule, collecting tubule, and duct. The podocytes of visceral epithelium contain large bi-lobed nuclei and their surface membranes pinch off vesicles into the cytoplasm. The processes of the podocytes give rise to pedicels that enclose narrow filtration slits. The endothelium of glomerular capillaries is attenuated and fenestrated. The short cytoplasmic processes of mesangial cells do not penetrate deeply into the sub-endothelial lamina. The glomerular basement membrane is about 286 nm in thickness. The pedicels also arise from podocyte cell bodies, and are connected by diaphragms and enclose slits, which open into narrow urinary spaces between podocytes. The cuboidal cells of the short neck segment display cilia with a characteristic pattern of 9+2 microtubules. The first proximal tubule segment differs from the second proximal segment in having densely packed microvilli, prominent endocytotic-lysosomal apparatus, and numerous basal membrane infoldings associated with mitochondria. The lateral cell membranes like those of other segments are straight and joined by desmosomes and apical adhering and tight junctions. The distal tubules display few short luminal microvilli and numerous basal mitochondria. The distal tubule, collecting tubule and duct are devoid of intercalated cells. The ultrastructure of the L chalumnae nephrons correlates well with their osmoregulatory function and resembles that of freshwater rainbow trout.

Antioxidants in prevention of cataracts in South India: methodology and baseline data*.

PURPOSE: To describe the methodology and baseline data for the Antioxidants in Prevention of Cataracts (APC) study in South India. METHODS: The APC study is a prospective, 5-year, randomized, triple-masked, placebo-controlled, field-based clinical trial to examine the effect of antioxidants (combination tablet of vitamins A, C, and E) on progression of cataract. The primary outcome variable is cataract progression (nuclear opalescence), evaluated with the slit-lamp biomicroscope by the Lens Opacification Classification System III method. Secondary outcome variables are progression in cortical and posterior subcapsular opacity and nuclear color, change in best corrected visual acuity, myopic shift, and treatment failure (progression to cataract surgery or best corrected vision worse than 20/400 in an eye). Inclusion criteria are age between 35 and 50 years and best-corrected visual acuity of 20/40 or better. Exclusion criteria are a diagnosis of diabetes mellitus or nonfasting blood glucose level>7.8 mmol/L, history or presence of various ocular conditions or treatment forms, or current use of vitamin supplements. Baseline ophthalmic, demographic, and potential cataract risk factor data (such as smoking, sunlight, or alcohol exposure) were compared between groups on an intent-to-treat basis. RESULTS: Of 954 people screened, 798 were enrolled, a sample size which exceeded the required estimate. More than 80% of subjects had 20/20 or better vision in at least one eye, and baseline prevalence of significant cataract according to the LOCS III grading scale was high. The two treatment groups were comparable for all baseline measures except alcohol intake. CONCLUSION: The sample size and group baseline characteristics will provide sufficient power to detect a change in cataract progression within 5 years.

Predictive value of frequency doubling technology perimetry for detecting glaucoma in a developing country.

PURPOSE: To determine the feasibility and diagnostic precision of Frequency Doubling Technology (FDT) perimetry as a method to detect glaucoma in rural villages of a developing country. DESIGN: Cross-sectional study. METHODS: Testing included FDT perimetry (C-20-5 screening protocol), tonometry, anterior segment biomicroscopy, and dilated ophthalmoscopy in 296 rural, non-English speaking residents of Southern India over 35 years old. Participants repeated the FDT if they had a location with reduced sensitivity or an unreliable result. We defined an abnormal FDT as one location of reduced sensitivity present on both the initial and repeat examination. We determined the diagnostic precision of FDT separately for a glaucomatous optic disc, a cup to disc ratio (C/D) > or = 0.7, and a C/D > or = 0.8. RESULTS: Ninety-three percent of subjects were able to complete the test satisfactorily. With repeat FDT testing, 37% of eyes with abnormal FDT results subsequently converted to normal and 67% of eyes with unreliable results subsequently became reliable. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for a glaucomatous optic disc were 7%, 87%, 13%, 76%, and 69%, respectively; for a C/D > or = 0.7, they were 0%, 87%, 0%, 91%, and 81%, respectively; and for a C/D > or = 0.8, they were 0%, 87%, 0%, 99%, and 87%, respectively. CONCLUSION: Clinicians can use FDT perimetry to rapidly screen for glaucoma in rural villages of a developing country. FDT testing had high specificity and negative predictive value, but low sensitivity and positive predictive value. The low sensitivity suggests that FDT has limited applicability as the sole test for glaucoma screening in this population. Repeat testing of FDT results that are unreliable or suspected of being abnormal is beneficial for this screening procedure.