Straylight and vision

Purpose Straylight is considered an important source of patient complaints. They can be voiced like halos, glare, hazy vision and blinding at night. With visual acuity, contrast sensitivity and slit lamp examination little may be found. Yet increased large angle light scattering in the eye media not detected by common tests, may degrade the image projected on the retina, thus decreasing the quality of vision. Aging changes to the crystalline lens and cataract are the most common causes of increased straylight. This study aimed to quantify the importance of straylight for daily life on the basis of patient complaint scores. Methods In a duocenter setting questionnaires were administered before and after cataract surgery. The 37 questions VFQ as well as a self developed 5 question straylight questionnaire were used. A comparison was made between the importance of visual acuity and of straylight to explain the questionnaire outcomes. Results A total of 214 patients were included in the study. For the comparison correlation coefficients were calculated between a weighted average of the 2 functional measures visual acuity and straylight on the one hand, and the questionnaire outcomes on the other. In all 4 cases (2 questionnaires x 2 visits) correlation was lowest for both visual acuity and straylight used in isolation. When visual acuity and straylight were combined to one combined score, correlation improved. Maximum correlation was found when visual acuity and straylight were combined 1:1 (preop) to 2:1 (postop), for both questionnaires. Conclusion For cataract patients, straylight is of about equal importance compared to visual acuity for their appreciation of daily function. In this comparison both were quantified as logarithms (logMAR and log(s)).