Ocular straylight in the normal pseudophakic eye

PURPOSE: To assess normal values for straylight in the pseudophakic eye as a function of age and to develop a model to predict the improvement in straylight after lens extraction based on preoperative straylight levels. SETTING: Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands. DESIGN: Review with retrospective cross-study analysis. METHODS: A literature review was performed to identify relevant papers on straylight and pseudophakia with no patient comorbidities. Sixteen papers met the eligibility criteria and were included in the analysis. The postoperative results were used to define the norm for straylight in pseudophakia. Stray light improvement after lens replacement was assessed by evaluation of preoperative and postoperative values. The age effect was incorporated to determine a model for straylight improvement. RESULTS: The mean postoperative straylight value derived from 16 studies (1869 eyes) was 1.21 log units +/- 0.21 (SD). Age dependence could be assessed from 13 studies (1533 eyes), resulting in the straylight age-norm curve in pseudophakic eyes as follows: Stray light value = 0.0044 x age + 0.89 with +/- 0.42 log units of 95% confidence interval. A strong correlation was observed between preoperative straylight and its improvement after lens extraction, yielding the following relationship: Straylight improvement = 1.04 x preoperative straylight value -0.006 x age -0.84. CONCLUSION: A norm for straylight in the pseudophakic eye was developed that is considerably different from the previously published norm for the phakic eye. The new pseudophakic norm can be used clinically to predict the straylight value after lens replacement and as a reference criterion for clinical studies.