ABSTRACT
Background The test for visual acuity is the conventional standard for evaluating visual quality.However,there is little correlation between visual acuity and visual disability.Therefore,other clinical observations such as contrast sensitivity or straylight have been used in the clinical assessment of visual quality after cataract surgery.Objective This study was to examine the change in the amount of straylight in cataractous eyes and to evaluate the correlation of the types of cataract with visual quality.Methods A non-randomized case-controlled study was designed.Eighty eyes of 40 patients with age-related cataract were enrolled in this study,including 22 eyes with hard nucleus cataract,19 eyes with cortical cataract,23 eyes with mixed cataract and 16 eyes with posterior subcapsular cataract diagnosed based on the criteria from Lens Opacities Classification System Ⅲ(LOCS Ⅲ).The values for straylight and best corrected visual acuity (BCVA) were measured with the C-quant straylight meter and Snellen chart,respectively.The differences in the straylight values among the different types of cataract were analyzed,and the correlation of the straylight value with age or BCVA was assessed.Forty eyes of 40 age-matched normal people served as controls.Results Examination was completed in sixty-two eyes of 31 patients in the cataract group at a completion rate of 77.5％,and all the subjects in the control group finished the examination at a rate of 100％.The mean straylight value was (2.06±0.88) log in the cataract group and (1.96±0.42) log in the control group,showing a significant difference between them (t =3.251,P＜0.01).The respective mean C-quant measurements for hard nucleus cataract,cortical cataract,nuclear-cortical cataract and posterior subcapsular cataract patients were (1.96±0.42) log,(1.91 ±0.16) log,(2.05 ±0.19) log and (2.48 ±0.66) log,respectively,with a significant difference among these four groups (F =2.156,P =0.019).The highest straylight value was detected in the posterior subcapsular cataract group.The straylight value was enlarged with the increase of age with a regression equation of Y=0.0010X+ 1.025 in the hard nucleus cataract group (r =0.455,P ＜ 0.05).In addition,the negative linear correlation was found between the straylight value and BCVA in both the hard nucleus cataract group and cortical cataract group (r=-0.590,-0.697,P＜0.01).However,no correlation was found in the mixed cataract group and posterior subcapsular cataract group (r =-0.240,-0.235,P＞0.05).Conclusions The C-quant straylight meter can objectively reflect the visual function for hard nucleus and cortical cataractous eye.Posterior subcapsular cataract produces straylight and exerts a great influence on visual quality due to early glare sensation,so it should be benefit to perform surgery earlier.
ABSTRACT
BackgroundBigbag intraocular lens (IOL),due to its special conducive design to support vitreous and retina after cataract surgery in high myopia,and ensure the visualization of peripheral retinal,is closely concerned.But whether its concave design has the advantage in reducing aberrations on the basis of stability or not is worth to be studied.ObjectiveThis study was to evaluate the high order aberrations(HOA) of phacoemulsification and the Bigbag IOL implantation in patients with myopia and cataract.MethodsA retrospective case-observational study was designed.Total 39 eyes of 39 cases with cataract and high myopia were enrolled in this study.The patients were divided into Bigbag IOL group and AR40e IOL group.Phaco-chop technique and IOL implantation were performed in April to June,2010 in Tianjin Eye Hospital.Two months after surgery,the operated eyes were clinical examined and the aberrations were detected including Root-Mean-Square (RMS),coma,spherical and Trefoil.Postoperative RMS values of HOA components of the whole and interior optic with iTrace were compared.Results The operation was smoothly with the correct IOL position after two months.No complication was found.Under the 4.5 mm pupil diameters,the whole ocular HOA RMS values and coma were significantly different between Bigbag IOL group and AR40e IOL group( t =-3.296 、-3.322,P＜0.05 ),but no significant differences were seen in spherical and Trefoil aberrations ( t =- 1.256、- 0.573,P＞ 0.05 ).Regarding to the interior optic with iTrace aberration,only the coma showed the significant difference between Bigbag IOL group and A R40e IOL group( t =-2.004,P＜0.05 ),and there were no significant differences in RMS,spherical and Trefoil aberrations( t=-1.073、0.380、0.288,P＞0.05 ).ConclusionsThe Bigbag IOL,a design for high myopia,is safe and effective after implant for the high myopia with cataract.It offers more exact obligate degree and better visual quality.The chief total and interior HOA components difference between groups is coma aberration.