The orientation of the optic-haptic junction of a monofocal intraocular lens (IOL) is significantly associated with the incidence of negative dysphotopsia following cataract surgery, with the horizontal orientation demonstrating the best performance at 4 to 6 weeks, according to research published in the American Journal of Ophthalmology.

Researchers conducted a prospective, randomized controlled trial to evaluate whether orientation of the optic-haptic junction of an IOL during cataract surgery could decrease the incidence or severity of positive and negative dysphotopsia.

Patients who were scheduled to have bilateral implantation of a monofocal IOL at a private practice were recruited and randomly assigned to have the optic-haptic junction positioned vertically, horizontally, superonasally, or inferonasally. The researchers surveyed patients for positive and negative dysphotopsia symptoms at 1 week and 4 to 6 weeks after surgery. 


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A total of 326 eyes of 163 patients (mean age, 73.75±7.31 years; 60.86% women) were included in the study. The IOL optic-haptic junction was oriented vertically in 25% of eyes, horizontally in 22% of eyes, superonasally in 29% of eyes, and inferonasally in 24% of eyes. 

At 1 week postoperatively, the researchers found that 21% of eyes had positive dysphotopsia and 14% of eyes had negative dysphotopsia. At 4 to 6 weeks postoperatively, they found that 21% of eyes had positive dysphotopsia and 10% of eyes had negative dysphotopsia. 

The team observed a significant association between orientation and incidence of negative dysphotopsia at 1 week postoperatively (P =.019) and 4 to 6 weeks postoperatively (P =.002). They found that patients in the superonasal group had the worst outcome at both assessments, while the horizontal group had the best outcome at 4-6 weeks. They found no associations between orientation and positive dysphotopsia incidence or severity.

Limitations of the study included lack of long-term follow up, lack of anterior segment photos, lack of post-operative assessment for IOL rotation, and a single assessment for both eyes at the 4 to 6 week dysphotopsia symptoms survey.

Reference

Pamulapati SV, Saeed JM, Pompey N, Gomez KD, Vakharia MR. Randomized controlled trial of IOL orientation for dysphotopsia. Am J Ophthalmol. Published online July 6, 2022. doi:10.1016/j.ajo.2022.06.018