Purchase this article with an account.
Marco U Morales, Saker Saker, Craig Wilde, Paolo G. Limoli, Winfried M K Amoaku; Selection criteria of the retinal locus used for biofeedback fixation training with microperimetry in patients with central vision loss.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3280.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Fixation stability (FS) of the Preferred Retinal Locus (PRL) may be improved by biofeedback fixation training (BFT) with microperimetry (MP). However the selection process of the fixation training target (FTT) locus has not been described. We performed an observational pilot study to test the hypothesis that our selection methodology of a functional retinal locus may improve eccentric fixation.
Fifteen study patients (SG), 11 female and 4 male (mean age = 72.5 years) and 5 controls (CG), 4 female and 1 male (mean age = 70 years), with bilateral central vision loss, no stable fixation and visual acuity (VA) worse than LogMAR 0.3, were recruited for BFT with MP (MAIA, Centervue). The eye with higher VA was chosen. A customized MP test (30°, 83 stimuli) was done. Projection strategy (MAIA 4LF) tested retinal sensitivity (RS) at four levels of intensity: 25, 15, 5 and 0 dB. RS was scored as “good”, “relatively good”, “relatively poor”, “poor” and “scotoma”. The retinal loci with at least 2 adjacent stimuli of good threshold sensitivity (GTS) were noted. A new MP exam (7°x5°, 35 stimuli) was done centered on the GTS loci with 4-2 projection strategy.Within SG, FTT was set between the 2 adjacent stimuli with the highest sensitivity and lowest distance from the anatomical fovea. On CG it was set in the patient’s baseline PRL.Twelve weekly BFT sessions were performed asking patients to move their gaze towards the selected FTT during 10 minutes. Biofeedback signals aid patients in the oculomotor process. Outcomes were: classification of fixation, FS area and VA. Linear regression was used to investigate relationships between variables.
All SG outcomes improved after BFT. At baseline, 10 eyes were classified as relatively-unstable and 5 with unstable fixation. After BFT, 5 eyes were classified as stable, 6 as relatively-unstable and 4 as unstable. Mean FS improved from 31.9±28.9 to 19.3±22.3 deg2. Mean VA from 1.3±0.57 to 1.0±0.6 LogMAR. On CG, mean FS got worse from 20.8±8.3 to 24.9±31.5 deg2 and mean VA did not change (1.4±0.6 to 1.4±0.8 LogMAR).
Our research provides a guideline to select the best retinal locus for BFT, with the aim to improve eccentric fixation with MP and biofeedback. Further studies are needed to prove the effectiveness of our methodology.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only