Factors affecting the total occlusion time in eyes with hyperopic anisometropic amblyopia.

BACKGROUND: Amblyopia treatment by occluding the healthy eye is known to be effective during a sensitive critical period. This study aims to clarify the factors for the total occlusion time (TOT) required for the amblyopic eye to achieve a normal visual acuity (VA) level of 1.0 (0.0 logMAR equivalent). This could contribute to an efficient treatment plan for eyes with hyperopic anisometropic amblyopia. METHODS: Subjects were 58 patients (26 boys and 32 girls; age range, 3.6-9.2, average, 5.8 ± 1.3 years) with hyperopic anisometropic amblyopia. All the subjects had initially visited and completed occlusion therapy with improved VA of 1.0 or better in the amblyopic eye at Kindai University Hospital between January 2007 and March 2017. Using the subjects' medical records, we retrospectively investigated five factors for the TOT: the age at treatment, the initial VA of the amblyopic eye, refraction of the amblyopic eye, anisometropic disparity, and the presence of microstrabismus. Patient's VA improvement at one month after treatment was also evaluated to confirm the effect of the occlusion therapy. RESULTS: The initial VA of the amblyopic eye ranged from 0.1 to 0.9 (median, 0.4). The TOT ranged from 140 to 1795 (median, 598) hours with an average daily occlusion time of 7 hours. The initial VA of the amblyopic eye and presence of microstrabismus were the significant factors for the TOT (p < 0.01). To achieve VA of 1.0 or better, patients with an initial VA of ≤ 0.3 in the amblyopic eye required a longer TOT. Moreover, patients with concomitant microstrabismus required a 1.7-fold longer TOT compared to those without microstrabismus. CONCLUSION: Longer daily occlusion hours and early start of the treatment will be necessary for patients with poor initial VA or microstrabismus to complete occlusion therapy within the sensitive critical period.

The Association Between Improvement of Stereoacuity and Suppression in the Treatment of Anisometropic Amblyopia.

Purpose: To investigate the association between stereoacuity and suppression during occlusion therapy for patients with anisometropic amblyopia. Design: Retrospective study. Patients and Methods: This study included 19 patients with hyperopic anisometropic amblyopia who underwent occlusion therapy. The mean age of the patients was 5.5 ± 1.4 years. The participants were evaluated for improvement in stereoacuity and suppression before beginning occlusion therapy, when the highest amblyopic visual acuity (VA) was achieved, during tapering, at the end of occlusion therapy, and at the final visit. Stereoacuity was evaluated using the TNO test or JACO stereo test. The presence of suppression was evaluated using circle No. 1 of the Stereo Fly Test or JACO results as the optotype. Results: Of the 19 patients, 13 (68.4%) had suppression before occlusion, eight (42.1%) when the highest VA was achieved, five (26.3%) during tapering, and none at the final visit. Of the 13 patients with suppression before occlusion, 10 (76.9%) showed further improvement in stereoacuity when suppression disappeared, and nine had foveal stereopsis of 60 arcseconds. A significant association was confirmed between foveal stereopsis and suppression when the highest VA was achieved and during the tapering period (P<0.05, Fisher's exact test). Conclusion: Suppression was observed even when the VA in amblyopic eyes reached the highest score. By gradually decreasing the duration of occlusion, suppression was eliminated, leading to the acquisition of foveal stereopsis.

Effects of orthoptic training for residual diplopia after surgical repair of blowout fractures.

PURPOSE: To investigate the effects of orthoptic training for residual diplopia after blowout fracture (BOF) surgery. METHODS: We retrospectively reviewed the medical records of 14 (average age, 22.9 ± 13.1 years) patients with residual diplopia, who had undergone orthoptic training after BOF surgery at the Department of Ophthalmology, Kindai University Hospital, between August 2013 and September 2019. The orthoptic training included exercises for eye movement, convergence, and fusional area expansion. We assessed the training effects by scoring patients' Hess screen (Hess) test results and fields of binocular single vision (BSV). The scores obtained before/after surgery and after training were compared. We also investigated the factors that influenced patients' BSV scores after training. p < 0.05 was considered statistically significant. RESULTS: The respective pre- and postoperative and after-training average scores were 7.0 ± 5.3, 5.4 ± 4.3, and 2.5 ± 3.2 points for Hess and 50.0 ± 41.3, 48.2 ± 35.9, and 89.4 ± 14.0 points for BSV. Neither Hess nor BSV score showed a significant difference before and after surgery (p > 0.05, the Steel-Dwass test). Compared to the postoperative (i.e., before training) scores, both Hess and BSV scores significantly improved after training (p < 0.05 for Hess, p < 0.01 for BSV; the Steel-Dwass test). CONCLUSION: Orthoptic training appeared effective in resolving residual diplopia after BOF surgery by improving patients' ocular motility and expanding the BSV field.