Retinal Nerve Fiber Layer Thickness in Amblyopic Eyes

Purpose: To compare the peripapillary retinal nerve fiber layer (RNFL) thickness of sound and amblyopic eyes. Design: Prospective observational case series. Methods: setting: Institutional. study population: Patients with unilateral strabismic, anisometropic, or combined amblyopia. observation: Fast RNFL analysis with ocular coherence tomography (OCT) of sound and amblyopic eyes. measure: Mean RNFL thickness. Results: For the 17 patients (mean age 10.7 years) in whom both eyes were imaged, the mean thickness of the sound eye was 109.2 μm (median 112.7) and of the amblyopic eye was 104.2 μm (median 105.0), and the average difference (sound eye less amblyopic eye) was 5.0 μm (median 3.0) (95% confidence interval -2.3, 12.2, P = .17). The sound eye was 10 μm or more thicker than the amblyopic eye in four patients; the amblyopic eye was 10 μm or more thicker than the sound eye in one patient; and the difference was within 10 μm in 12 patients. Test-retest data were obtained for 23 pairs of sound eyes and 21 pairs of amblyopic eyes, with 75% of the test-retest pairs within 7%. Conclusions: We found a small, but not clinically significant, difference in nerve fiber layer (NFL) thickness between amblyopic and sound eyes. Reliability was excellent, with most eyes testing within 7% of the first test.