Analysis of Mp-1 audio-biofeedback impact on fixation in low vision patient with maculopathy
Abstract
Purpose
To study the impact of a low vision rehabilitation strategy based on Nidek MP-1 auditory biofeedback (BFB).
Methods
Retrospective study of 39 eyes/26 consecutive patients referred for low vision rehabilitation. Patients received 8 monocular training sessions of BFB, each of 10 minutes duration, 7–14 days apart. Microperimetry, ETDRS VA and Pelli-Robson was performed at the beginning and at the end of the sequence. BFB employs a sound to train the patient to keep a specific gaze position.
Results
Age median was 70. Pre-BFB logMAR VA was 1, logCS 0.60. Post-BFB logMAR VA was 1, logCS 0.75. Dense central scotomas and eccentric fixation locations were detected in 35 eyes/24 patients, and relative scotomas with central fixations in 4 eyes/2 patients. Mean sensitivity was 7.60 dB pre-BFB, and 8 db post-BFB. Pre-BFB fixation stability was 24% within 2°, and 67% within 4°; post-BFB, it was 25% within 2°, and 64% within 4°. BCEA analysis showed pre-BFB values for 68.2% BCEA to be 3.6, and 4.46 post-BFB. After BFB, no significant difference was found for any of the above-mentioned parameters in the sample as a whole. Nevertheless, grouping cases by change in pre-vs post-BFB BCEA (group A: decrease in BCEA, n = 21; group B: increase in BCEA, n = 18) showed a significant difference in terms of BCEA itself, and in the related fixation stability (p < 0.05).
Conclusions
Although no significant difference in VA, CS, mean sensitivity, fixation stability at 2° and 4°, and BCEA was found after BFB in the sample as a whole, still there was an improvement in 21 eyes (53.8%) in terms of BCEA and fixation stability. Grouping analysis demonstrated that, while other tested outcome measures were not affected, some cases did respond significantly to BFB improving their fixation stability.
