Interocular Axial Length Difference and Treatment Outcomes of Anisometropic Amblyopia

Purpose: To evaluate the effect of interocular axial length (AL) difference on outcomes of treatment for anisometropic amblyopia in comparison with normal participants. Methods: In this historical cohort study, 83 patients with anisometropic amblyopia were divided into two age groups, 70 children (mean, 7.86 +/- 1.56 and range, 5-15 years) and 13 adults (mean, 26.46 +/- 10.87 and range, 16-45 years). The control group consisted of 43 non-amblyopic children and 17 non-amblyopic adults. Treatment outcomes after a period of one year were defined as successful or unsuccessful when posttreatment amblyopic corrected distance visual acuity (CDVA) was reported as <= 0.9 versus CDVA <= 0.8, respectively. AL was measured using a Lenstar LS900 (Haag-Streit AG, Switzerland). Results: Fifty-nine patients showed satisfactory treatment outcomes (55 children and 4 adults), while unsuccessful treatment outcomes were observed in 24 patients (15 children and 9 adults). The mean of amblyopia treatment duration was 1.24 +/- 0.76 years. The mean of interocular AL difference in all patients, control, successful and unsuccessful treatment outcome groups were 0.49 +/- 0.70mm (range, 0.00-3.89 mm), 0.12 +/- 0.07 mm (range, 0.02-0.41), 0.33 +/- 0.23 mm (range, 0.00-0.99 mm), and 1.81 +/- 0.80 mm (range, 1.14-3.89 mm), respectively. In both age groups, the mean of interocular AL difference in patients with unsuccessful treatment outcomes was greater than those with successful treatment outcomes and that of the control group (P < 0.001). Conclusion: The results of this study suggest that the outcome of anisometropic amblyopia treatment may depend on the interocular AL difference.