THE EFFECT OF OPTIC ZONE DIAMETER ON CHOROIDAL RESPONSE USING BIFOCAL SOFT MULTIFOCAL CONTACT LENSES

Abstract

Purpose : The aim of this study is to assess the impact of varying optical zone diameters of multifocal lenses used for myopia management by measuring their effects on the choroidal volume.

Methods : This is a prospective study made on 18 myopes (14 F; 4 M, -2.18D), randomly fitted with customized bifocal contact lenses with different distance zone diameters (L1: 2.3 mm, L2: 4 mm, L3: 7 mm, same peripheral add power of +10D). Visual demand, activities and food intake were controlled. Choroidal thickness was measured using OCT at baseline (no lens) and after 45 minutes of wear. A 15-min washout was observed between measurements. Choroidal volume variation was estimated through computer analysis. (Matlab).

Results : Choroidal volume changes were noticeable with each lens from baseline (L1: +1.25% ±7.04 L2: -2.55% ± 3.98 L3: -7.74% ±7.66 ), with an increase in the choroidal volume only for the smaller distance zone diameter. Significant difference was found between L1 and L3 (p=0.003), and between L2 and L3 (p=0.045). The choroidal volume response in the central 1X1 mm zone varied for each lense ( L1: max= +12.54 mm³ , min= -17.37 mm³ ; L2: max= +11.62 mm³ , min= -15.83 mm³ ; L3: max= +6.95 mm³ , min=-12.46 mm³).

Conclusions : The results of this study indicate that a reduced optical zone diameter is more effective in increasing the choroidal volume. Future work is needed to determine the impact to rely on smaller diameters for myopia control.

This is a 2021 ARVO Annual Meeting abstract.