Optical quality difference between monofocal and multifocal intraocular lenses
Reviewed by Kurt Spiteri Cornish

It is well known that multifocal intraocular lenses (IOLs) can generate more than one focus to restore distance and near vision, but patients may experience adverse optical phenomena such as decreased contrast sensitivity and induced glare or halos. The authors therefore assessed and compared in vivo optical and visual performance of eyes implanted with monofocal and multifocal IOLs in this prospective non-randomised clinical study. Postoperative examination included measures of Objective Scatter Index (OSI), which quantifies intraocular scattered light; Modulation Transfer Function (MTF) cut-off, which represents the highest spatial frequency at which the eye can focus an object on the retina; Strehl Ratio (SR), which is the measure of the fractional drop in the peak of the point spread function (a ratio of 1.0 indicates a perfect optical system). Eighty eyes of 57 patients were included in the study. Groups were comparable preoperatively, including in corneal aberrations. Postoperatively, visual acuity was similar in the two groups. The multifocal lens provided favourable visual outcomes at both distance and near in daytime without refractive correction. However, there was statistically significant differences in OSI (higher in multifocal group), MTF cut-off and SR values (lower in multifocal group). Contrast visual acuity was also lower in the multifocal group.

Evaluation of optical quality: ocular scattering and aberrations in eyes implanted with diffractive multifocal or monofocal intraocular lenses.
Liao X, Lin J, Tian J, et al.
CURRENT EYE RESEARCH
2018;46(6):696-701.