Half Minimally Invasive Strabismus Surgery (MISS): A single para-muscular approach to horizontal muscle strabismus surgery

PURPOSE: Minimally invasive surgeries are gaining popularity. We compared two different approaches to rectus muscles: namely the standard para limbal (SPL) and the single para-muscular (SPM). METHODS: Thirty-six patients planned for monocular horizontal strabismus surgery were block randomized to SPL and SPM approach. SPM approach involved a single para-muscular 10-mm conjunctival incision levelled at the inferior border of rectus muscle. We compared the post-operative grades of redness, congestion, chemosis, foreign body sensation, and drop intolerance at day 1, 2 weeks, and 6–8 weeks; scar visibility and success rates at 6–8 weeks and operation duration in minutes. We compared the results using Mann–Whitney U-test for inflammatory grades, Fisher’s exact test for proportions, and t-test for parametric measures. Significance was set at P < 0.05. RESULTS: On postoperative follow-up at any time point, no significant difference was found on comparing inflammatory grades, scar visibility, and success rates. In terms of duration, SPL approach was on an average 21.5 minutes quicker than SPM (P = <0.001). CONCLUSION: The SPM is comparable to the SPL approach in terms of postoperative comfort and appearance, but takes significantly longer to accomplish.