Comparison of Visual Outcomes for Aspheric and Spherical Toric Intraocular Lens Implantation in Cataract Patients with Pre-Existing Corneal Astigmatism: A Randomized Control Trial
Pichit Naripthaphan MD*, Pongsak Pachimkul MD*, Somporn Chantra MD*
Affiliation : * Department of Ophthalmology, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand
Background : With spherical intraocular lens (IOL) implantation, unaided vision of cataract patients with pre-existing
corneal astigmatism is unsatisfactory because astigmatic spectacles will always be needed for clear vision. Toric IOL has
been proven to be a major improvement in cataract surgery for spectacle independence. Aspheric property, reported to
improve visual quality in a non-toric IOL, has now been added to toric IOL for even better unaided vision.
Objective : To compare visual and aberrometric outcomes of 2 toric IOL, spherical and aspheric, at 3 months after implantation.
Material and Method: Cataract surgery was performed in cataract patients with pre-existing corneal astigmatism using 2
types of toric IOLs, a spherical toric IOL, Acrys of SN60T, (Group A) and a aspheric toric IOL, Acrts of SN6AT, (Group B)
as a randomized control trial. The uncorrected distance (UDVA) and corrected (CDVA) distance visual acuities, residual
astigmatism, spherical equivalent (SE) and spherical aberration were evaluated 3 months after implantation.
Results : The present study included 44 eyes. No statistically significant difference was found in UDVA, CDVA and residual
astigmatism between both groups. The UDVA of 0.1 logMAR or better was found in 78.26% in Group A and 85.71% in Group
B. In Group A, 78.26% of eyes and in Group B, 76.19% had a refractive astigmatism value within 0.50 diopter at KP90 (polar
value along the 90-degree meridian). The spherical equivalent (SE) was within +0.5 diopter of emmetropia in 91.30% in
Group A and in 80.95% in Group B. Group B had significantly lower spherical aberration Z (4, 0) than Group A.
Conclusion : Both groups had similar clinical effectiveness for unaided visual acuity, aided visual acuity and astigmatism
correction. Group B had significantly less spherical aberration induction when compared with Group A.
Keywords : ToricIOL, Cataract surgery, Astigmatism correction
