Role of overminus therapy in intermittent exotropia

Abstract

Aim: The aim is to study the change in Newcastle Control Score (NCS) and angle of deviation after a trial of overminus therapy in intermittent exotropia (IXT). Context: Overminus therapy in IXT. Settings and Designs: This prospective observational study was conducted at Comtrust Eye Hospital, Calicut, Kerala, which is a tertiary eye care center from July 2015 to May 2017. Materials and Methods: Fifty-three children with IXT, aged 1–5 years, were recruited. NCS scores and angle of deviation were recorded. Treatment was instigated with the minimum minus lens required to achieve control of the manifest deviation. NCS and angle of deviation were recorded with the overminus glasses at 6 weeks, 6 months, and 1 year. Statistical Analysis: Data were tabulated and analyzed using the SPSS software (SPSS statistics for Windows 17.0 Chicago, SPSS Inc). Paired t-test was used to compare change in NCS and angle of deviation before and after treatment. P < 0.05 was taken as statistically significant. Results: Fifty-three children were recruited, 31 females and 22 males with a mean age of 3.6 ± 1.633 years. Majority were of the basic type of IXT. The NCS at 1 year showed significant reduction from baseline values. At 1 year, 27% patients had the same NCS as baseline, 32% showed a reduction by 1, 21% reduced by 2, and 5% showed a reduction by 3 in the total score. The angle of deviation with the overminus for both distance and near also showed significant reduction. Conclusion: This study showed definite improvement in control of IXT with overminus, and hence, a trial of overminus therapy is recommended for IXT in children below 5 years, as surgery has its own side effects like overcorrection, leading to consecutive esotropia with loss of stereopsis and high amount of recurrence.

Keywords

• Intermittent exotropia
• Newcastle Control Score
• overminus