DEC 19, 2012
This prospective study in the May issue of the Journal of Cataract & Refractive Surgery assessed straylight in cataract patients before and after surgery, and determined that straylight and visual acuity measure different aspects of vision quality and influenced subjective visual quality almost equally. When straylight was added to preoperative considerations of cataract extraction, postoperative results were more predictable.
The study's authors note that while straylight measurements are objective, visual acuity measurements are more subjective. The definition of a "visually significant cataract" may change in the next few years, pushing a large portion of Medicare-covered procedures into the private realm. But as before, it will be based on the old, inadequate Snellen chart. This article underscores how other objective measures may be more appropriate for decision making.
The study included 217 patients undergoing cataract surgery. Preoperative and postoperative questionnaires showed that straylight had almost the same influence as visual acuity on quality of vision. After cataract surgery, mean visual acuity and straylight improved (by 0.26 logMAR and 0.31 log[s], respectively), although improvement in overall vision (taking both visual acuity and straylight into account) exceeded that of visual acuity and straylight separately (0.35).
The authors say the results show that straylight and visual acuity behave quite independently and each contributes to the overall quality of vision. They say that measurement of straylight is easily performed in the clinic and would be a clinically useful tool for better predicting postoperative improvement after cataract surgery.