Biofeedback fixation training as an important tool to supplement strabismic amblyopia treatment in aduls—preliminary results

Abstract

Aims/Purpose: Fixation stability may be a biomarker of strabismus and amblyopia recurrence after strabismus surgery and therapeutic interventions to improve visual acuity in amblyopic eyes, respectively. We have recently shown that it is possible to improve fixation stability in adult amblyopic eyes after strabismus surgery using microperimetric biofeedback fixation training (BFT). In this study we evaluated the effects of BFT on fixation stability influencing monocular and binocular visual functions in adult patients with amblyopia.Methods: Participants were 18 patients with monocular amblyopia (mean age = 35.2 ± 9.8 years; 6 females, 3 anisometropic, 5 strabismic and 10 mixed amblyopia). BFT has been applied monocularly to 13 amblyopic eyes either on the spontaneous preferential retinal locus (PRL) or to a fixation area close to the PRL. The other five subjects did not undergo BFT (control group). Best‐corrected visual acuity (BCVA near and distance), monocular (PRL) and dichoptic contrast sensitivity function (CSF) and fixation stability (BCEA 68%) were measured three times: baseline, after 10 and after 20 BFT sessions or twice within 6 months interval for the controls.Results: Baseline fixation stability correlated positively with monocular amblyopic BCVA and CSF, especially in the high frequency range, whereas it was positively associated with dichoptic amblyopic CSF only in the low frequency range, most likely reflecting binocular imbalance. Preliminary results showed that BFT applied to amblyopic eyes improved fixation stability and visual functions. However, some clinical conditions may be required to achieve significant changes.Conclusions: BFT applied to adult amblyopic eyes is a new potential approach to aid in the treatment of suppresive amblyopia in adult patients. Critical pre‐treatment fixational and/or sensorial criteria associated with satisfactory therapeutic effects of BFT on amblyopia remains to be investigated.