Miki et al measurements in children have been reported12–14 and have been found to be acceptably reproducible.15 The interocular asymmetry of RNFLT in 6-year-old children has been assessed, and the interocular average RNFLT has been found to be moderately correlated.16 Therefore, the evaluation of the interocular asymmetry of RNFLT can be validated. In this study, we used OCT in patients with persis- tent and recovered amblyopia. We sought to determine whether or not a change in RNFLT is associated with the persistence of amblyopia by examining these two groups of patients. Materials and methods Fifty-four patients with a history of unilateral amblyopia were enrolled in the study. All the patients had been treated for amblyopia. This treatment had included the correction of refractive errors and the patching of the sound eye or instillation of atropine in the sound eye. Patients enrolled in this study had amblyopia caused by strabismus, anisometro- pia, or both. Data from three patients were excluded from further analysis because of a low signal strength, poor image quality, or poor fixation during the measurements. Accord- ingly, we analyzed the data from 51 patients. These patients were divided into two groups: 52 eyes of 26 patients with persistent amblyopia (16 male and 10 female, whose ages ranged from 5 to 30 years (10.9 ± 6.3 years) when the images were taken) and 50 eyes of 25 patients who had recovered from amblyopia (6 male and 19 female, whose ages ranged from 5 to 35 years (8.4 ± 6.0 years). All patients underwent a complete eye examination, including cycloplegic refrac- tion. The final best-corrected visual acuity (BCVA) of the amblyopic eye ranged from 20/200 to 20/30. The BCVA of the fellow eye of the patients with persistent amblyopia and the recovered amblyopic eye was equal to, or better than, 20/20. All these patients were followed up for more than Dovepress 5 years to ascertain that the improvement in visual acuity had reached a plateau. In each patient, the RNFLT was measured through a study of dilated pupils using the Stratus OCT™ (Carl Zeiss, Dublin, CA). Informed consent was obtained from each patient. The principles of the OCT have been described elsewhere.10 All of the OCT scans were performed by an experienced operator blinded of the patient’s identity and the results of any other tests. The fast RNFL algorithm was used to obtain the RNFLT measurements. Three images, each consisting of 256 A scans along a 3.4 mm-diameter circular ring around the optic disc, were acquired and were then averaged for analysis. Only scans with a signal strength of at least 6 were accepted. SPSS 17.0J (SPSS Japan, Inc., Tokyo, Japan) was used to perform the statistical analysis. A paired t-test was used to assess the difference in parameters between amblyopic (previous or persistent) and fellow eyes in patients with persistent amblyopia and those with recovered amblyopia. An unpaired t-test was used to assess the differences in parameters between the amblyopic eyes of patients with persistent amblyopia and the previously amblyopic eyes of patients with recovered amblyopia. Logistic regression analysis was applied to adjust for the effect of refraction. P values of less than 0.05 were considered to be statisti- cally significant. Results In patients with recovered amblyopia and those with persistent amblyopia, the affected eyes were significantly more hyperopic than the fellow eyes (Table 1). There was no significant difference in RNFLT between the affected and fellow eyes in each group. In addition, logistic regression analysis adjusting for refraction showed that there was no significant difference in RNFLT between the amblyopic eyes of patients with persistent amblyopia and the previously Table 1 Comparison of refraction and retinal nerve fiber layer thickness Comparison between affected and contralateral eyes Recovered amblyopia (50 eyes of 25 subjects) Persistent amblyopia (52 eyes of 26 subjects) Contralateral eye Affected eye P* Contralateral eye Affected eye P* refraction (diopters) 1.725 (2.173) 3.365 (3.492) 0.002 1.499 (2.272) 3.468 (3.941) 0.003 Retinal nerve fiber layer thickness (µm) 104.39 (9.24) 107.13 (11.69) 0.201 105.16 (12.99) 105.48 (13.97) 0.477 Comparison between affected eyes of recovered and persistent amblyopia refraction P = 0.965 Retinal nerve fiber layer thickness P = 0.565 Note: Data are shown as “mean (standard deviation)”. refraction: spherical equivalent values. P values are for comparison between affected and fellow eyes* (paired t-test) and between the affected eyes of recovered and persistent amblyopia (unpaired t-test). 1062 submit your manuscript | www.dovepress.com Dovepress Clinical Ophthalmology 2010:4