Pre-operative minimal-cycloplegia mydriasis for capsulorrhexis in hypermature intumescent cataract

Abstract

 Conventionally adrenergic-anticholinergic combination eye drops (e.g., phenylephrine-tropicamide) are used for pre-operative pupillary dilatation in cataract surgery. This achieves synergy in dilatation, but anticholinergic-induced cycloplegia makes already tense lens-capsule of intumescent cataract more taut, and completion of capsulorrhexis becomes difficult, often resulting in Argentanian flag sign, peripheral extension. An alternative mydriasis-without-cycloplegia strategy (phenylephrine) is also tried for better maintenance of mydriasis but it’s capsule-slackening effect was not thought of. Making best of both, we practice a ‘minimal-cycloplegia mydriasis’ approach (MCM) comprising of 0.25% tropicamide and 5% phenylephrine, instilled in succession. This study was planned to compare our MCM regimen with the conventional fixed-dose-combination regimen of 0.8% tropicamide and 5% phenylephrine (Standard). To compare the ease and smoothness of capsulorrhexis and relative incidence of complications, in hypermature intumescent cataract surgery, between ocular instillation of alternative ‘MCM’ regimen and the traditional ‘Standard’ regimen.  The study used a prospective observational 2-arm comparison design. The study commenced with due approval of Institutional Ethics Committee. Sixty-one (61) patients (age range: 42-72yrs, number of Male: Female 19:42) undergoing hypermature intumescent cataract surgery by standard SICS+IOL technique and in whom either of two regimens, MCM or ‘Standard’ were used for papillary dilatation, were observed. Outcome analysis was done by Fisher’s Exact Test. Out of a total of 61 cases, 29 received MCM regime and 32 received ‘Standard’ cycloplegic dilator. Difference in dilatation between two groups was statistically non-significant. Frequency of completed rhexis and attainment of post-operative BCVA of 6/12 were higher with MCM regime: p< 0.001 and p< 0.0005 respectively. Anterior chamber reactions on first post-operative day was more frequent with MCM regime (p<0.01), but was transient and cleared totally in a week. Minimal-cycloplegia dilatation regime comprising of 0.25% tropicamide and 5% phenylephrine, instilled in succession may be preferred for capsulorrhexis in hypermature intumescent cataract.