Fixation Pattern Analysis With Microperimetry In Strabismic Subjects: A Pilot Study

ABSTRACT

Objective

Strabismic amblyopia is a motor and sensory deficit produced by unilateral constant strabismus and binocular imbalance. The aim of this study was to analyse the retinal fixation pattern using microperimetry in subjects with strabismus with and without amblyopia associated, and to compare the results with those obtained in normal subjects.

Methods

Prospective comparative study conducted at the Optometric Clinic of the University of Valencia and Oftalvist Alicante (Spain) including 46 eyes with ages from 3 to 16 years. Three groups were differentiated: patients with persistent strabismic amblyopia after occlusion and active therapy (group 1, 7 patients, 30.4%), strabismic patients without amblyopia (group 2, 8 patients, 34.8%) and a control group (8 patients, 34.8%). Microperimetric analysis was performed with the Macular Integrity Assessment (MAIA) system (Centervue, Padova, Italy) and using the following parameters: P1% and P2% fixation indexes, and the ellipse areas (BCEA) for 95% and 63% of points for the first 10 seconds, 30 seconds, 60 seconds, and the total examination time.

Results

Significant differences were found between groups for dominant eyes in P2 calculated at 30 (p = .04) and 60 seconds (p = .03). However, these differences between groups in non-dominant eyes were close to statistical significance (p = .07 and p = .08). Specifically, P2 was significantly lower in group 1 compared to control group (p = .01). Best corrected visual acuity was found to be significantly correlated (p ≤ .04) with total P1 (dominant eye, r = −0.51; non-dominant eye, r = −0.50), total P2 (dominant eye, r = −0.50; non-dominant eye, r = −0.50), and BCEA63 (dominant eye, r = 0.50; non-dominant eye, r = 0.40) and BCEA95 (dominant eye, r = 0.50; non-dominant eye, r = 0.40) measured at 10 seconds.

Conclusions

The preliminary results of this study seem to indicate that subjects with strabismus have fixation instability regardless of the presence or absence of amblyopia.

KEYWORDS:

• Eye fixation
• fixation instability
• microperimetry
• strabismic amblyopia
• strabismus

Disclosure Statement

The authors have no proprietary or commercial interest in the medical devices that are involved in this manuscript. The author David P Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471.

Additional information

Funding

This work was supported by the Ministerio de Economía, Industria y Competitividad, Gobierno de España [RYC-2016-20471].