High-add Trifocal Magniners for Low Vision

Abstract

High-add trifocals double the reading distance of high-add bifocals. They allow patients to read small print close up, while preserving the ability to read larger print at an intermediate distance. Binocular vision can be produced by prescribing reading additions up to +6.00 diopters (D). However, the segments must be decentered-in 6 mm each for each eye according to the rule of thumb, which states that binocular reading segments must be decentered-in 1 mm for each diopter of reading addition for each eye. Monocular high-add trifocals are practical up to +16.00 D reading addition. The success rate of 70 patients evaluated was 84%.