Automated And Subjective Refraction With Monofocal, Multifocal And Extended Depth Of Focus Intraocular Lenses – A Review

Automated refraction is universally used to start the visual exam. This review was conducted as a guide for the examiners who may not be aware of the systematic or random biases induced by specific models of commercial IOLs.

University Hospital of Parma

Autorefractor results (Scheiner principle) with monofocal, multifocal, and extended-depth-of-focus (EDOF) IOLs were investigated through literature search. A number of 23 keywords were entered into the PUBMED and EMBASE database, and papers reporting the difference between automated and clinical refraction were analysed. The research was last updated on November 30, 2022.

A total of 2,842 eyes from 23 studies were included in the final analysis. The discrepancy between automated and clinical refraction was reported minimal with monofocal IOLs. Differently, all the considered multifocal and EDOF IOLs induced an overestimation of myopia in automated refraction. The average difference ranged between -0.50 D to -1.00 D with reference to refractive multifocal or EDOF IOLs and was around -0.25 D with diffractive multifocal IOLs with distant refractive focus. IOLs with distant diffractive focus, either multifocal or EDOF, induced the highest difference, and up to -2.00 D. The differences in astigmatism were much lower, with exception.

Autorefractors using infrared light cannot measure eyes with high technology IOLs precisely. The refractive or diffractive near add appear to influence the measures in different ways. The systematic error induced with some IOLs should be mentioned in the IOL label to avoid misunderstanding and to prevent possible inappropriate refractive procedures to treat apparent myopia.