Optimised minus lens overcorrection for paediatric intermittent exotropia: A randomised clinical trial

Abstract

Background: Aim of this study was to evaluate the efficacy of a novel algorithm to customise overminus lens therapy in intermittent exotropia (IXT) based on clinical factors associated with control of the deviation. Methods: Clinical parameters in IXT vary among individuals. Based on individual's physiological factors, an algorithm was developed. Children aged between 4 and 15 years with IXT were randomised into OML and observation groups. Participants in the observation group were corrected for any significant refractive error. IXT control score, angle of deviation, refraction, axial length and stereopsis were examined at baseline and follow up ranging between 6 and 15 months and compared. Compliance and tolerance to OML was determined by a symptom survey. Results:The OML power ranged between À1.00D and À 6.25D. Of the total 141 participants (mean age 6.8 ± 2.5 year), 77 were in the OML and 66 were in observation group. IXT control score improved (mean difference À 2.5 ± 1.1; p < 0.001) and angle of deviation reduced (6.9 ± 7.2pd; p < 0.001) significantly in the OML group only. Compliance rate to OML wear was 80%; 90% never or rarely experienced asthenopia symptoms. Slightly greater myopic shift (À0.36 ± 0.53D vs. À0.18 ± 0.55D) and change in axial length (0.17 vs. 0.14 mm) were observed in the OML group, but these differences were not statistically significant. Conclusions: A customised OML, calculated using this novel algorithm was effective in improving distance control, angle of deviation and stereopsis. Glasses wear was highly tolerable.

The Influence of Overminus Lens Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Clinical Trials

“…All studies employed the standardized office-based 6-point scoring system. Ale Magar et al [7] evaluated the effectiveness of OML therapy on control of 141 children with IXT aged from 4 to 15 years according to the follow-up ranged from 6 months to 15 months. They developed an algorithm to achieve a practically personalized customization of the OML requirement for the treatment of IXT children for individuals and revealed the efficiency of OML therapy in improving distance control, angle of deviation, and stereopsis.…”

“…In the random-effects model, heterogeneity remained evident. A sensitivity analysis was conducted to look for sources of heterogeneity and we found the study by Ale Magar et al [7] to be the main source of heterogeneity. The study focused on comparing OML therapy with OBS for IXT and developed a practical algorithm.…”

The influence of commonly used non-surgical treatment modalities on control of intermittent exotropia: A meta-analysis of randomized clinical trials

“…In the random-effects model, heterogeneity remained evident. A sensitivity analysis was conducted to look for sources of heterogeneity and we found the study by Jit et al to be the main source of heterogeneity 7 . The study focused on comparing overminus lenses therapy with observation for intermittent exotropia and developed a practical algorithm.…”

“…Overminus lens therapy and occlusion therapy for intermittent exotropia are frequently prescribed nonsurgical treatment modalities. Recently, several randomized controlled trials (RCTs) have directly compared these two treatment modalities with observation (watchful waiting), with mixed results [3][4][5][6][7][8][9] . A meta-analysis is necessary to better understand the effectiveness of overminus lens and occlusion therapy in the treatment of IXT.…”

Is there an optimal minus lens power to help manage intermittent exotropia?

“…This journal reports a novel, customised approach for choosing the power of "optimised" minus lenses (OMLs) to manage IXT. 3 The author's formula for choosing OML power was based on (1) the angle of deviation, (2) the gradient accommodative convergence to accommodation (AC/A) ratio for a near object, (3) the IXT distance Office Control Score 4 and (4) the amplitude of accommodation (AA) observed in the office for each patient. Each element of their formula is logical, and the sequential combination used in the algorithm makes sense.…”