Robust and reproducible population receptive field mapping in patients with retinal pathologies

Previous studies have shown high reproducibility of population receptive field (pRF) mapping in young, healthy individuals. The present study examines whether such a level of reproducibility can also be achieved in patients suffering from retinal disease.

Eleven patients with Stargardt disease and eleven patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) were examined in up to four sessions using high-resolution ultra-high field fMRI (Siemens Magnetom 7 T) and microperimetry (MP, Nidek MP-3). Reproducibility of the pRF parameters within and between sessions was assessed using Spearman's correlation coefficient.

Retinotopic maps calculated from ultra-high field MRI had excellent intra- and intersession reproducibility for pRF center position (median correlation between sessions for pRF center eccentricity: r = 0.91; polar angle: r = 0.90), but only modest reproducibility for pRF size (average correlation r = 0.39). Reproducibility was constant across sessions multiple weeks apart, indicating a long-term stability of the method. In addition, the results show that reproducibility is not related to the severity of retinal disease.

The data demonstrate that retinotopic mapping of the primary visual cortex using ultra-high field MRI is a highly reproducible technique for the assessment of macular function in patients with retinal disease. The technique provides an unbiased quantification of retinal function adjunct to conventional clinical assessments and may assist the early diagnosis of retinal disease. In addition, it may be a valuable objective method for monitoring visual deficits during long-term therapeutic interventions or disease progression.