What are the implications of the Straylight domain for the clinician

Purpose Straylight is 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, but many corneal conditions including laser treatment have been reported to increase straylight as well. Methods In order to evaluate the importance of straylight for clinical decision making, the quantity in which straylight is expressed must attain a meaningful value. Straylight is expressed logarithmically, as the logarithm of the straylight parameter s, which directly relates straylight to the (outer skirt) of the functional point‐spread‐function: s = θ^2 PSF. It was found earlier that expressed this way, the straylight value has functionally about equal importance as logMAR. The functional value of straylight was further corroborated by Aspinal et al., finding that straylight was the better predictor of clinical decisions on cataract surgery, as compared to visual acuity. Results Implications for the clinician include a shift in targeting of patient care. On the basis of straylight elevation treatment can be offered in cases where visual acuity is good. In the case of optical malfunction of the eye, as simple model for functional severity of the condition, the linear average of visual acuity in logMAR and straylight in log(s) is proposed. Data from population study on >5000 eyes show significant retargeting of cataract surgery. Conclusion Straylight retargets patient care.Commercial interest