Fixation pattern analysis with microperimetry in nystagmus patients.

Abstract Objective To assess the usefulness of microperimetry (MP) as an additional objective method for characterizing the fixation pattern in nystagmus. Design Prospective study. Participants Fifteen eyes of 8 subjects (age, 12–80 years) with nystagmus from the Lluis Alcanyis Foundation (University of Valencia, Spain) were included. Methods All patients had a comprehensive ophthalmologic examination including a microperimetric examination (MAIA, CenterVue, Padova, Italy). The following microperimetric parameters were evaluated: average threshold (AT), macular integrity index (MI), fixating points within a circle of 1° (P1) and 2° of radius (P2), bivariate contour ellipse area (BCEA) considering 63% and 95% of fixating points, and horizontal and vertical axes of that ellipse. Results In monocular conditions, 6 eyes showed a fixation classified as stable, 6 eyes showed a relatively unstable fixation, and 3 eyes showed an unstable fixation. Statistically significant differences were found between the horizontal and vertical components of movement ( p = 0.001), as well as in their ranges ( p p p r = 0.812, p = 0.014), MI ( r = –0.812, p = 0.014), P1 ( r = 0.729, p = 0.002), horizontal diameter of BCEA ( r = –0.700, p = 0.004), and X range ( r = –0.722, p = 0.005) were found. Conclusions MP seems to be a useful technology for the characterization of the fixation pattern in nystagmus, which seems to be related to the level of visual acuity achieved by the patient.