Abstract
Purpose :
Effectiveness of traditional amblyopia therapies is largely restricted to childhood, but recovery in adulthood is known to occur following removal or vision-limiting disease of the fellow eye (FE). Descriptions of this phenomenon are limited to case reports and small series, leaving knowledge gaps related to the incidence and clinical features of amblyopic eye (AE) recovery in adulthood. To address these gaps, we performed a meta-analysis of published cases. Regarding clinical features, we hypothesized that (1) FE retinal ganglion cell (RGC) injury is associated with better AE recovery, (2) strabismus blunts AE gains and (3) AE improvement is directly associated with the degree of FE vision loss.
Methods :
A systematic review of 3 literature databases yielded 23 reports containing 109 original descriptions of patients ≥18 years with unilateral amblyopia and FE injury. Two meta-analyses were performed: (1) incidence: 3 case series (42 patients) reporting qualifying patients agnostic to recovery; (2) clinical features of recovery (hypotheses 1-3): 101 patients with any quantifiable AE best-corrected visual acuity (BCVA) improvement.
Results :
Incidence: 32/42 (76%) and 29/42 (69%) adult amblyopic patients experienced ≥1 and ≥2 logMAR lines of AEBCVA improvement with FE disease.
Clinical Features: Among those with AE BCVA improvement, median change in AE BCVA was 5.0 (range 0.5–19.2) logMAR lines. Recovery occurred across amblyopia types and FE pathologies, contrary to hypotheses 1 and 2. FE disorders directly affecting FE RGCs demonstrated shorter latencies to AE BCVA recovery by 4 months (p<0.0124). Multivariate regression analysis revealed younger age, worse baseline AE BCVA, and worse nadir FE BCVA (supporting hypothesis 3) were independently associated with the greater gains in AE BCVA (p values<0.006).
Conclusions :
The adult brain harbors the neuroplastic capacity necessary for clinically meaningful recovery. AE gains are greater with worse FE BCVA impariment and faster with disorders affecting RGCs. These results support the potential therapeutic utility of temporary retinal inactivation in adults with amblyopia.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.