The Influence of Intraocular Monofocal Lens Position During Phacoemulsification Cataract Surgery on the Occurrence of...

The study aimed to evaluate the occurrence and intensity of positive and negative dysphotopsias in patients with different intraocular lens (IOL) positions - vertical, horizontal, superonasal, and inferonasal - and to determine whether IOL position correlates positive or negative dysphotopsias.

This prospective cohort study included 80 patients, divided into four equal groups based on IOL positioning. Each group received a monofocal hydrophobic acrylic IOL during ultrasound phacoemulsification cataract surgery. Patients with horizontally placed IOL served as the control group. In each group, there were twenty participants. Clinical assessments, including visual acuity and biometry measurements, were recorded preoperatively and 1 month postoperatively. Post-surgery, patients completed a questionnaire evaluating the presence and severity of dysphotopsias.

Positive dysphotopsia was reported by 26.3% of patients, with no significant difference among the groups (Fisher's exact test, p=0.63). Negative dysphotopsia appeared in 11.3% of patients, significantly more frequent in those with superonasal and inferonasal IOL positions (Fisher's exact test, p=0.01). Regarding the IOL location, there was no discernible difference in the severity of positive (Kruskal-Wallis test, p=0.33) and negative (Kruskal-Wallis test, p=0.23) dysphotopsias among patients who were experiencing them. Postoperatively, all patients demonstrated improved visual acuity, anterior chamber depth, and axial length measurements.

The study found a significant association between IOL position and the incidence of negative dysphotopsia, especially with inferonasal and superonasal placements. However, the IOL position did not influence the intensity of either positive or negative dysphotopsia. This implies that post-surgery negative dysphotopsia perception is influenced by lens location. Patient satisfaction remained high, though negative dysphotopsia intensity negatively correlated with satisfaction scores.