Abstract
Purpose :
Handheld spectral-domain optical coherence tomography (HH-OCT) can be used to diagnose foveal hypoplasia in infants. However, it unclear whether HH-OCT can predict future visual acuity in infants with foveal hypoplasia. We performed a longitudinal cohort study to assess whether grading foveal hypoplasia can predict future visual acuity in patients with infantile nystagmus.
Methods :
We recruited patients with infantile nystagmus aged between 6 and 24 months at the time of their first HH-OCT and graded their initial scans. Foveal tomograms were graded using the Thomas et al grading system for foveal hypoplasia: Grade 1: shallow foveal pit, presence of outer nuclear layer (ONL) widening, presence of outer segment (OS) lengthening; Grade 2: Grade 1 but absence of foveal pit; Grade 3: Grade 2 but absence of OS lengthening; Grade 4: Grade 3 but absence of ONL widening; atypical foveal hypoplasia: shallow foveal pit, disruption of the inner segment ellipsoid band. Patients were followed up 19.61 to 52.89 (mean: 39.78, S.D. 8.70) months later when they could reliably co-operate with logMAR visual acuity measured with Glasgow and/or Cardiff Acuity Cards. Data was analysed using a linear mixed regression model including both foveal hypoplasia grading, eye recorded and age at testing (both OCT imaging and visual acuity) in the model.
Results :
We imaged 38 eyes from 19 patients with infantile nystagmus aged between 7.16 and 23.90 (mean: 12.45, S.D. 4.79) months at the time of their first HH-OCT. This patient cohort included albinism (n=12), idiopathic infantile nystagmus (IIN) (n=6) and achromatopsia (n=1). Foveal hypoplasia was identified in 31 eyes which included Grade 1 (n=19), Grade 2 (n=0), Grade 3 (n=4), Grade 4 (n=6) and atypical foveal hypoplasia (n=2). Normal tomograms were seen in seven eyes. Foveal hypoplasia grading was a strong predictor of visual acuity later in life (p<0.001; F=59.3; β=0.19, 95% CI = 0.14 to 0.24).
Conclusions :
Our findings demonstrate a strong correlation between the severity of foveal hypoplasia using our grading system in infancy with visual acuity at a later age when reliable. HH-OCT has the potential to predict future visual acuity in infants with foveal hypoplasia.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.