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Influence of cataract morphology on retinal straylight and straylight changes due to cataract surgery using the Morcher 89A Bag in the LensTM
Author(s) -
TASSIG MJ
Publication year - 2010
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2010.3425.x
Subject(s) - medicine , visual acuity , ophthalmology , retinal , cataract surgery , optometry , cataracts , contrast (vision) , optics , physics
Purpose To evaluate straylight and contrast sensitivity (CS) in eyes with various cataract morphologies, to determine which type of cataract presents a higher impairment of visual function with respect to proposed norms car driver safety and to compare retinal straylight and CS before and after implantation of a Morcher 89A IOL. Methods BCVA, CS and straylight were measured in 97 cataractous eyes using respectively a Snellen chart, a Pelli‐Robson chart and the C‐Quant. Cataracts were graded using the LOCS III scale and divided into four groups: nuclear, cortical, nuclear‐cortical and posterior subcapsular cataract. These results were compared to data from 38 cataract‐free control subjects. A separate group of 71 eyes had their straylight measured before and after cataract surgery. Results CS was reduced and straylight increased in all cataract patients, most notably in posterior subcapsular and nuclear‐cortical cataract. CS and BCVA were correlated (r=0.44), whereas straylight and BCVA were not. Applying cut‐off values as proposed by European drivers studies of l.25 log CS and 1.4 log straylight as safe margins for driving, 31% would be considered unfit to drive on the basis of CS and 78% on the basis of straylight although their visual acuity was still above the current European visual acuity requirement for driving. Retinal straylight reduced significantly from 1.560.26 to 1.250.22logunits (P<0.001) after IOL implantation . Conclusion Straylight and, to a lesser extent, CS are complementary to BCVA and should be taken into account when considering driving eligibility. After IOL implantation straylight reduces significantly, resulting in a significant increase in driving eligibility.