Importance of Early Squint Correction Surgery: A Reflection of Postoperative Visual Outcome and Complications after Strabismus Surgery Done in Regional Institute of Ophthalmology, Kolkata

Introduction: Strabismus surgery improves the ocular alignment, cosmetic appearance and interpersonal interactions with elimination of diplopia and compensatory head posture. Strabismus can be caused due to sensory deprivation or motor causes which includes myogenic, neurogenic or neuro-muscular junctional causes. The age group of 1-6 years is important because binocular vision can be impacted by intervention. Complications like scleral perforation, lost muscle, anterior segment ischaemia, anterior segment infections, under-correction, over-correction, suture granuloma, dellen formation or diplopia can occur after strabismus surgery. Materials and Methods: We conducted a study on 80 eyes of 54 patients who attended the Paediatric ophthalmology and Squint clinic of the outpatient department of Regional Institute of Ophthalmology, Kolkata for a duration of 1 year. Preoperative details analysed were laterality, type of strabismus, amount of deviation, best corrected visual acuity (BCVA) before the surgery, presence of refractive error, amblyopia, and binocular single vision (BSV). Cover uncover test was done, Prism bar cover test (PBCT) both for distance and near was done in primary position, up gaze and down gaze to measure the amount of correction required and Worth 4 dot test and Synaptophore test was done to check BSV. The optimum BCVA was documented at 2 weeks before the surgery. Intraoperatively, Forced Duction Test (FDT) was done to rule out restrictive squint, number of muscles operated upon was also noted. Postoperative details analysed were residual magnitude of strabismus (if any), BCVA and presence of complications (for example diplopia, over-correction, under-correction, or any local complications). Outcome at 6 months was classified as straight (orthophoria), under correction or overcorrection. All patients with a postoperative deviation < 10 prism dioptres (PD) at 6 months were considered to have a successful outcome (orthophoria). Postoperative BCVA was also documented. Results: This study was conducted on 80 eyes, among which we have complete data on 77 eyes. Male and female patients were almost equal Esotropia was more common (52.5%) than exotropia (47.5%). 83.75% patients achieved satisfactory alignment at 6 months post-operative follow-up. 75% patient achieved visual acuity of 6/12 or better. We observed suture granuloma in 5% of patients. There was under-correction in 12.5% patients but no over-correction was there. Diplopia was observed in 2 patients at 6 months follow-up. We have noticed association between age of surgery and post-operative visual outcome, in our study there was better visual prognosis among the younger age groups. We have also experienced association between age of surgery and postoperative residual angle of deviation. There was association between pre-operative angle of deviation and post-operative angle of deviation.