Biofeedback fixation training method for improving eccentric vision in patients with loss of foveal function...

Fixation stability (FS) of the preferred retinal locus (PRL) may be improved by biofeedback fixation training (BFT) with microperimetry. Such training can be done on the patient's PRL or in different retinal loci with better functional characteristics. We studied both options and compared the outcomes.

Sixty-seven consecutive patients with bilateral central vision loss, poor FS and visual acuity (VA) lower than 0.3 LogMAR were recruited for BFT with microperimeter. Patients were assigned into 2 groups. In group A, BFT was performed on the patient's spontaneous PRL. In group B, PRL was located between 2 adjacent loci with the highest light sensitivity and the lowest distance from the fovea. Two sets of 12 weekly BFT sessions were performed. Primary outcomes were: FS, VA and reading speed.

Outcomes were statistically significantly better in group B. Mean percentage of FS at therapy end improved from 32 to 35% for group A and from 40 to 55% in group B. Mean VA improved from 1 to 0.86 in group A and from 1 to 0.84 in group B. Reading speed (wpm) improved from 56 to 58 in group A and from 63 to 89 in group B.

This study describes a reliable methodology of improving eccentric fixation stability using BFT in microperimetry, when the fixation training locus is individualized as the retinal area with best functional characteristics. Further studies are needed to validate its value in a larger scale of patients, at different stages of the disease, and its persistence over time.