Microperimetry Deemed Useful for Functional Assessment in Foveal Hypoplasia

Macular microperimetry is a useful tool for evaluating pediatric patients with foveal hypoplasia due to its ability to provide functional data that correlates with visual acuity in patients affected by the condition, according to research published in the Canadian Journal of Ophthalmology. 

This retrospective study included patients with foveal hypoplasia (n=16; eyes, 31; mean age, 12.4 years; 9 boys) treated at a single pediatric clinic between 2016 and 2018. All participants underwent comprehensive ophthalmic examinations which included spectral-domain optical coherence tomography (SD-OCT) and automated microperimetry evaluation. The investigators examined correlations between best-corrected visual acuity (BCVA) and functional and structural data. 

Stratified by foveal hypoplasia grade, a total of 2 patients had grade 1, 7 patients had grade 2, 3 patients had grade 5, and 2 children had grade 4 hypoplasia. Fixation was stable in 11 participants, relatively unstable in 12 children, and unstable in 8 individuals. The patients had a mean [SD] BCVA of 0.43 [0.16] logarithm of the minimum angle of resolution (logMAR), central retinal thickness of 294 [17] μm, macular sensitivity of 28 [2.6] dB, and fixation of 63% [26].

Correlations were observed between BCVA and nystagmus (r, 0.64), fixation index (r, -0.60), and macular sensitivity (r, -0.63). Central macular thickness was correlated with macular sensitivity (r, 0.33), foveal hypoplasia grading (r, 0.31), BCVA (r, -0.31), and nystagmus (r, -0.36). Fixation stability was associated with BCVA (F_[1,29], 19.49; P =.0001).

Stratified by fixation, significant central fixation differences were observed among patients with and without clinical nystagmus (P =.027). However, these differences were not  observed between patients with and without nystagmus among a group with non foveal fixation (P =.49).

“In this study, we have demonstrated higher correlations between BCVA and [microperimetry] outcomes than between BCVA and central macular thickness or the different degrees of [foveal hypoplasia],” according to the researchers. “This underscores the importance of incorporating [microperimetry] functional examinations into evaluations of these patients in addition to anatomic assessments with OCT.”

Study limitations include a small sample size and the absence of a molecular diagnosis of foveal hypoplasia pathogenesis among study participants.