Alternative diagnosis in cases of poor response to amblyopia therapy
Reviewed by Fiona Rowe

The aim of this study was to assess the prevalence of coexistent ocular pathology and identify / describe the factors that contribute to undiagnosed alternate diagnosis and / or co-existent pathology at initial presentation in patients referred as potentially amblyopic. This was a retrospective study with children grouped to A: primary diagnosis of amblyopia, and B: final diagnosis of coexistent alternative pathology. Of 482 children with an initial diagnosis of amblyopia, and with sufficient follow-up and ophthalmic examinations, 466 had a final diagnosis of amblyopia alone and 26 had persistent reduced best corrected visual acuity. Of 26 children, six had a re-diagnosis of alternative condition – two keratoconus and four cases of subclinical optic neuropathy. The remaining 20 children had alternative aetiology for their reduced visual acuity including eight cases of ametropic amblyopia – the most frequent alternative diagnosis – seven with anisometropic amblyopia, three stimulus deprivation and three strabismic amblyopia. Median time to establishing the alternative diagnosis was 18.5 months (range 3–34). Final alternative diagnosis / co-existent pathology included occult macular dystrophy (n=10), subclinical optic neuropathy (n=13), keratoconus (n=2) and juvenile retinoschisis (n=1). The most common clue to alternative diagnosis was lack of visual acuity improvement despite good compliance (n=21). Median best corrected visual acuity was 0.45logMAR after six months follow-up. Median time of amblyopia treatment was 9.5 months. Other clues included subtle optic disc pallor (n=11), reduced colour vision (n=7), history of parental consanguinity (n=7) and preceding febrile illness (n=1). For those diagnosed with optic neuropathy, they showed reduced colour vision (n=7), disc pallor (n=10), visual field reduction (n=13) and visual evoked potentials (VEP) abnormalities (n=9). For cases of occult macular dystrophy, all had reduced central responses on mfERG. Overall, a final alternative diagnosis was made for 5.1% of children. The authors highlight the importance of careful ophthalmic examination where improvement of visual acuity with amblyopia therapy is not as expected, despite good compliance.

Subnormal visual acuity after compliant amblyopia therapy: residual/refractory amblyopia or co-existing pathology? – a retrospective analysis.
Sachdeva V, Bhattacharya B, Ganatra S, Kekunnaya R.
STRABISMUS
2024;32(1):11–22.