Dysphotopsia and location of laser iridotomy: a systematic review

This systematic review aimed to clarify the relationship between the location of laser peripheral iridotomy (LPI), a common procedure to prevent or treat angle-closure glaucoma, and the incidence of post-procedure visual disturbances known as dysphotopsias. Understanding this relationship is crucial due to the high frequency of LPIs performed and the significant impact dysphotopsia can have on vision and quality of life. Articles investigating the relationship between LPI location and dysphotopsia in at least five patients were identified via a literature search of OVID MEDLINE (1946-November 19, 2022) and EMBASE (1946-November 19, 2022). Non-comparative and non-English studies were excluded. Studies did not require a control group to be included. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system and Cochrane Risk of Bias 2 (RoB2) tool were used to appraise included studies. Our review included three studies encompassing 1756 eyes from 878 patients. The location of LPI was grouped into superior (604 patients, 889 eyes), inferior (150 patients, 150 eyes), and nasal/temporal (443 patients, 717 eyes). The analysis showed no significant difference in the incidence of any new dysphotopsia types among the location groups post-LPI. Overall, the incidence of lines, ghost images, and blurring significantly increased after LPI, while halos and glare significantly decreased. In conclusion, the current literature suggests that the location of LPI has no significant relationship to the types and rates of dysphotopsia experienced thereafter. While there is a 2-3% risk of linear dysphotopsia after LPI regardless of location, LPI may also resolve pre-existing halos and glare.