ABSTRACT
<p><b>BACKGROUND</b>Contrast sensitivity (CS) testing can detect differences in functional vision and is highly correlated with visual performance. This study was designed to investigate the association between CS and the grading score using the lens opacities classification system (LOCS) III as well as the association between CS and visual acuity (VA) in nuclear or cortical age-related cataract (ARC) patients.</p><p><b>METHODS</b>A total of 270 eyes with ARC and 30 control eyes were divided into nuclear opacity (NO), nuclear color (NC), cortical cataract (C) based on LOCS III. The CS values measured at all spatial frequencies under photopic and glare conditions that resulted in contrast sensitivity function (CSF) were evaluated, and LogMAR VA was tested with the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The correlation between CSF and LOCS III grading scores, and between CSF and LogMAR VA were analyzed.</p><p><b>RESULTS</b>Compared to the controls, CSF of the nuclear or cortical ARC significantly declined. There are significant correlation between CSF and LogMAR VA, and between CSF and LOCS III grading scores. Compared to the VA, a stronger correlation existed between CSF and LOCS III grading score than that of LogMAR VA and LOCS III grading score. CS at some spatial frequencies is significantly influenced with LOCS III grading score.</p><p><b>CONCLUSIONS</b>CSF significantly declined with the increasing ARC grading scores. Comparing to VA, CSF reflected the severity of cataract more comprehensively. CS at low spatial frequency is significantly influenced by ARC. Therefore, CS is more precise than VA in assessing the visual function of ARC patients.</p>
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Cataract , Classification , Contrast Sensitivity , Physiology , Visual AcuityABSTRACT
Background Ultraviolet radiation is one of factors of the formation of age-related cataract.Indole-3-carbinol(I3C) is a plant chemical material with inhibitory effect on oxidative-induced cell damage and formation of amyloid fibrils,and the oxidative damage and amyloid fibrils are associated with cataract.However,the relationship between I3C and α-crystallin is in study. Objective This study was to evaluate the effects of ultraviolet-B laser irradiation on the secondary structure of α-crystallin and to explore the protection of I3C to chaperone activity of α-crystallin. Methods The fresh eyeballs were obtained from 1-year-old cattle to prepare the purified lens α-crystallin by gel chromatography.α-Crystallin was isolated from cattle lenses using gel chromatography.The purified α-crystallin was collected using fast protein liquid chromatography ( FPLC ) and exposed to 1:308 nmultraviolet-B at different irradiation intensities ( 23.75,118.75,475.00,1187.50,2375.00,4750.00,11 875.00,23 750.00 mJ/cm2 ) and then to ultraviolet-B 2:308 nm with irradiation intensities of 28 535.00,6730.00,3435.00,1910.00,1040.00 mJ/cm2.Ultraviolet-absorbance spectra,tryptophan fluorescence and N-formylkynurenine (N-FK)fluorescence spectra of both irradiated and non-irradiated α-crystallin were measured.I3C at the concentrations of 50 μmol/L and 100 μmoL/L were added to the α-crystallin solution to perform a catalase (CAT) thermal aggregation to confirm the chaperone activity of the α-crystallin,and the α-crystallin solution without any I3C was used as control.The ratios of A360 between various intervene groups with control group were calculated using spectrophotometry.Results The A280 values of the α-crystallin declined to 10％ at the ultraviolet-B irradiation intensity of 1187.5 mJ/cm2 and that at the intensity of 23.75 J/cm2 lowed to 2％.A negative correlation was seen between the ultraviolet-B irradiation intensity and the A280 value of the α-crystallin (R2=0.925 ) and a positive correlation was found between ultraviolet-B with N-FK ( R2 =0.949 ).Ultraviolet-B irradiation intensity showed a negative correlation with Trp fluorescence intensity (R2 =0.996 ).CAT hot condensed experiment revealed that after addition of different concentrations of indole-3-carbinol,the relative A360 values at various ultraviolet-B irradiation group were significantly higher than those of the control group (P =0.000),and the decreasing degree of chaperone activity of α-crystallin was lower than that of the control group ( P =0.000 ). Conclusions The study suggests that I3C can protect the chaperone activity of α-crystallin from photooxidation,and the ultraviolet-B laser may be a good exposure source compared with ultraviolet lamp.The ultraviolet-B laser irradiation causes the alteration of structure and chaperone activity of α-crystallin.