Improvement of Visual Acuity as An Aftereffect of Blur Adaptation through a Defocusing Lens

Our previous study has shown that blur adaptation through a foggy filter temporarily improved visual acuity (VA). Here we report the influence on VA from the adaptation to blurred images by a defocusing lens. In the experiment, a subject adapted to the blurred visual field by observing motion pictures through a trial lens either of 2.5D, 3.0D, 4.0D, or 5.0D. The visual acuity was measured in the periods of pre- and post-adaptation by a quick and simplified staircase method with Landolt C. The moment the lens was removed, subject's VA was obviously higher than the original VA and then gradually returned to the original level in a few minutes. However the degree of transient improvement in VA was not necessarily larger with longer period of adaptation. The enhancement in VA demonstrated here is presumably caused by blur adaptation and its aftereffect. The usual VA might not be the optimum performance of the hardware of an eye, or rather, be suppressed by the visual system in the level of the cortex

An integrative study of the genetic, social and environmental determinants of chronic kidney disease characterized by tubulointerstitial damages in the North Central Region of Sri Lanka

Objectives: Previous investigations on chronic kidney disease of unknown etiology characterized by tubulointerstitial damages (CKDu) in the North Central Region (NCR) of Sri Lanka have supported the involvement of social, environmental and genetic factors in its pathogenesis. Methods: We conducted a social-environmental-and-genetic epidemiology study on a male population in NCR to investi2014gate the genetic and environmental contributors. We recruited 311 case-series patients and 504 control candidates. Of the 504 control candidates, 218 (43%) were eliminated because of the presence of hypertension, proteinuria, high HbA1c, high serum creatinine or high alpha-1 microglobulin in urine. Results and Discussion: None of 18 metals measured (μg/l) in urine, including Cd, As and Pb, showed significantly higher concentrations in cases compared with controls. As speciation results showed that 75-80% of total urinary As was in the form of arsenobetaine, which is non-toxic to humans. None of the metal concentrations in drinking water samples exceeded guideline values. A genome-wide association study (GWAS) was conducted to determine the genetic contributors. The GWAS yielded a genome-wide significant association with CKDu for a single nucleotide polymorphism (SNP; rs6066043; p=5.23 Ã 10-9 in quantitative trait locus analysis; p=3.73 Ã 10-8 in dichotomous analysis) in SLC13A3 (sodium-dependent dicarboxylate transporter member 3). The population attributable fraction and odds ratio for this SNP were 50% and 2.13. Genetic susceptibility was identified as the major risk factor for CKDu. However, 43% of the apparently healthy male Lankapopulation suffers from non-communicable diseases, suggesting their possible influence on CKDu progression