Concentric macular rings: ultrawide-field biomarker in pediatric albinism

To evaluate the prevalence and clinical relevance of the concentric macular rings (CMR) sign on ultrawide-field (UWF) imaging as a noninvasive marker of foveal hypoplasia (FH) in pediatric patients with albinism, in whom optical coherence tomography (OCT) acquisition is limited by nystagmus and poor fixation.

The medical records of pediatric patients with albinism who underwent UWF imaging, green-filter UWF, and OCT were reviewed retrospectively. CMR presence, morphology and size were assessed using standard UWF imaging, green-filter, and red-filter modalities. Best-corrected visual acuity (BCVA), cycloplegic refraction, FH grade, macular pigmentation, genetic mutations, and associated features (nystagmus, strabismus) were analyzed.

A total of 128 eyes of 64 patients (mean patient age, 11.3 years; 55% males) were analyzed. Mean BCVA was 0.5 logMAR; and 62.5% of eyes had nystagmus. FH stages 3 and 4 were observed in 48.3% and 45.7% of eyes, respectively. CMR sign was identified in 70.4% on UWF retinography and in 75% using the green filter. Mean largest ring diameter was 3.4 ± 1.05 mm; median ring count was 10 per eye. Interobserver agreement was substantial on standard UWF and almost perfect on green-filter UWF (κ = 0.815). Ring number correlated with FH grade (P = 0.006) and BCVA (P = 0.034). The presence of this sign was significantly associated with hyperopia (P = 0.001), macular hypopigmentation, and FH grade (P < 0.001).

The CMR sign on UWF retinography, particularly with a green filter, may serve as a noninvasive diagnostic aid for FH in albinism, especially in pediatric patients or those with fixation difficulties.