Effectiveness of visual and acoustic biofeedback eccentric viewing training in conjunction with home exercises on visual function: a retrospective observational review.

The aim of this study is to evaluate the effectiveness of an eccentric viewing training program that combines biofeedback training using micro-perimetry with home exercises on multiple visual function parameters and to explore potential relationships between post-treatment visual function parameters. A retrospective observational review of 27 participants who underwent the training program was performed. Eligible participants were diagnosed with bilateral central scotomas secondary to age-related macular degeneration. All participants undertook up to 15 visual and acoustic biofeedback training sessions and were required to partake in traditional home exercises between sessions. The biofeedback training was conducted in the better eye using the Macular Integrity Assessment microperimeter (MAIA). Distance and near acuity, contrast sensitivity and fixation stability quantified by the P1 and P2 values and the 63% and 95% bivariate contour ellipse area (BCEA) before and after the rehabilitation program were recorded. Significant improvement was noted post-training for distance visual acuity (t(26) = 4938 p = .000), near visual acuity (Z = -4.461 p = .000), contrast sensitivity (Z = -3.647 p = .000) and fixation stability for all measures, including P1 (t(26) = -9.490 p = .000), P2 (t(26) = -7.338 p = 0.000), 63% BCEA (Z = 3.569 p = .000) and 95% BCEA (t(26) = 4.687 p = .000). Significant medium-to-large correlations were also found between most visual function variables. Visual and acoustic biofeedback in conjunction with home exercises has the potential to improve visual function parameters in patients with age-related macular degeneration and irreversible central vision loss.

An Overview of Preferred Retinal Locus and Its Application in Biofeedback Training for Low-Vision Rehabilitation.

Central vision loss (CVL) caused by macular damage generally disables common daily tasks, which cannot be reversed by present treatments. Fortunately, it has been found that biofeedback training by inducing or reinforcing preferred retinal locus (PRL) as an eccentric fixation reference contributes to the improvement of visual performance in patients with CVL. However, the clinical application is still under controversy due to poor knowledge of its fundamental and inconsistent practical standards. This article aims to summarize the possible rationale for the development, location, re-location and evaluating indicators of PRL, and the general apparatus, protocol, and outcome of biofeedback PRL training.