Comparison of higher order aberrations in eyes with aspherical or spherical intraocular lenses

Abstract

Purpose To compare ocular, internal, corneal aberrations, and contrast sensitivity in patients implanted with aspheric or spherical intraocular lenses (IOLs). Methods Total, corneal, and internal aberrations were measured using ray-tracing technology in 23 eyes implanted with aspheric (Tecnis ZA9003) IOLs, and in 25 eyes implanted with spherical (AcrySof SA60AT) IOLs. Spherical aberration (SA), coma, trefoil, and RMS of higher order aberrations (HOAs) were analysed for 4.0 and 6.0 mm optical zones. Best-corrected visual acuities (BCVAs), contrast sensitivity under photopic and mesopic conditions, and modulation transfer function (MTF) were evaluated to compare visual performances. Results The mean internal SA was À0.06/ À0.35 lm in the aspheric IOL group and 0.04/ 0.17 lm in the spherical IOL group (at 4 mm/ 6 mm pupil). Total SA was near to zero in the aspheric IOL group, and was 0.11±0.034/ 0.48±0.13 lm in the spherical IOL group. The internal Z 3 À1 and total Z 3 À1 were more negative in the spherical IOL group. The internal Z 3 À3 was more negative in the aspheric IOL group. The two groups were similar in terms of other Zernike values and RMS of HOA. There were no differences in BCVA between groups. The aspheric IOL group showed better contrast sensitivity at 3-6 cpd in photopic and 1.5-6 cpd in mesopic conditions. The MTF curve was better for the aspheric IOL group at 5-10 cpd. Conclusions The aspheric IOL with a negative SA reduced total SA by compensating for positive corneal SA. These effects resulted in improved contrast sensitivity.

Effect of intraocular lens asphericity on vertical coma aberration

“…In other words, we found the lowest coma aberration values for aspheric IOLs and the highest with conventional spherical IOLs. Our findings concur with those of Bellucci et al 21 and Kim et al, 22 who also found reduced vertical coma after implantation of an aspheric IOL. Unaided reading ability in monofocal pseudophakic eyes is dependent on the interplay of several factors that increase the depth of focus; these factors include residual myopia, against-the-rule astigmatism, 25 pupil size, 26 and HOAs.…”

“…However, we also found reduced vertical coma and distance-corrected near visual acuity in eyes with the aspheric IOL. Bellucci et al 21 and Kim et al 22 also found reduced vertical coma after implantation of aspheric IOLs. Clinical studies of HOAs have not discussed the changes in vertical coma in detail.…”

Effect of interaction of macroaberrations and scattered light on objective quality of vision in pseudophakic eyes with aspheric monofocal intraocular lenses

“…Indeed, new aspheric IOLs have been designed to compensate for corneal spherical aberrations and improve optical performance (ie, contrast sensitivity) in pseudophakic eyes. [5][6][7][8][9][10]14,[24][25][26][27][28][29] However, essential aspects must be kept in mind when correcting visual aberrations. First, given these scenarios, the clinical impact is largest with a large dilated pupil as well as in situations such as night driving.…”

Advances in cataract surgery

“…One study found no significant difference in contrast sensitivity between spherical and aspheric lenses after three to four months. 52 Other studies have reported significant improvement in contrast sensitivity, 53,54 without a reduction in pseudo-accommodative amplitude. 55 A reduction in the depth of focus that can result from asphericity is an important consideration as most patients undergoing cataract surgery are presbyopic.…”