[Comparative assessment of the parameters of visual fixation in amblyopia of different origin]

Examination of visual fixation parameters is an important diagnostic method in patients with amblyopia of different origin.

To study the visual fixation parameters for various types of amblyopia.

The study included 108 patients (213 eyes) aged 5-11 years with moderate and high amblyopia: 27 patients (54 eyes) with strabismic amblyopia, 45 patients (87 eyes) with refractive and anisometropic amblyopia, and 36 patients (72 eyes) with relative amblyopia caused by deprivation nystagmus. All examinations were performed on the NIDEK MP-1 Microperimeter.

Fixation density within 2° and 4°, the amplitude of the horizontal and vertical fixation point displacement, the averaged value of the fixation point displacement and the average velocity of displacement were evaluated. There was a positive correlation between visual acuity and fixation density for all types of amblyopia, the higher the visual acuity, the higher the fixation density in the area of 2° and 4°. The maximum values of the displacement point amplitude were registered in patients with nystagmus. In patients with strabismic amblyopia, hyperopia and myopia values of displacement point amplitude were lower. The highest average displacement and rate of displacement of the fixation point were found in the group of patients with nystagmus. The differences were much less significant in other groups.

A comparative objective study of visual fixation parameters for various types of amblyopia was performed using the NIDEK MP-1 Microperimeter. There was a positive correlation between fixation density decrease, the increase of amplitude and average displacement of the fixation point, and visual acuity decrease for all types of amblyopia. There was no significant correlation between average rate of displacement and visual acuity. The maximum disturbance of fixation parameters, including the average rate of the fixation point displacement, was registered in nystagmus.