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Multifocal toric IOL alone yields better spectacle independence
Mean residual refractive astigmatism was higher in eyes that received a non-toric multifocal IOL with corneal relaxing incisions compared with eyes that received a toric multifocal IOL alone.
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A toric multifocal IOL yielded significantly less residual corneal astigmatism than a non-toric multifocal IOL combined with peripheral corneal relaxing incisions, according to a study.
Both methods resulted in significant improvement in unaided visual acuity for distance and near in cataract patients with moderate astigmatism, the study authors said.
“The most significant finding was that toric multifocal IOLs do yield good results, and our patients achieved greater spectacle independence at both distance and near,” Vincenzo Maurino, MD, the corresponding author, told Ocular Surgery News.
The study was published in the Journal of Cataract and Refractive Surgery.
Study design and methods
The prospective randomized clinical trial included 58 eyes of 29 patients with visually significant cataract and 1 D to 2.5 D of corneal astigmatism; mean preoperative corneal astigmatism was 1.82 D in the toric multifocal IOL group and 1.67 D in the non-toric multifocal IOL group.
Patients received an M-flex T toric multifocal IOL (Rayner) in one eye and a non-toric M-flex multifocal IOL combined with one or two peripheral corneal relaxing incisions in the fellow eye.
Target postoperative refraction was emmetropia.
The primary outcome measures were visual acuity, astigmatic vector reduction, digital toric IOL axis determination, spectacle dependence and patient satisfaction. Patients were evaluated 1 month and 3 months after surgery.
“The aim was to try to give patients higher spectacle independence by using in each eye a multifocal premium lens and then addressing the concomitant corneal astigmatism in one eye by a toric component in the multifocal lens itself (multifocal toric IOL) and in the fellow eye by limbal relaxing incisions,” Maurino said.
Maurino noted that the study was undertaken before the authors had access to femtosecond laser technology.
“What we did was use manual peripheral corneal relaxing incisions using the Donnenfeld nomogram,” he said.
Results and conclusions
At 3 months, mean residual refractive astigmatism was 0.45 D in the toric group and 0.72 D in the non-toric group. The between-group difference was statistically significant (P = .046).
Mean uncorrected distance visual acuity was 0.10 in the toric group and 0.15 in the non-toric group. Mean uncorrected near visual acuity was 0.43 in the toric group and 0.39 in the non-toric group. Between-group differences were insignificant.
“Because our patients had relatively low levels of pre-existing corneal astigmatism, there was not a huge difference between the two groups,” Maurino said. “Yet, despite the low astigmatism, there was a trend toward better visual outcomes in eyes where astigmatism was corrected with toric multifocal lenses compared with eyes where the astigmatism was corrected with multifocal lenses and peripheral corneal relaxing incisions.”
Mean absolute misalignment of the intended axis of toric IOLs was 2.52°; maximum misalignment was 6°. Toric IOL rotation was within 3° in 90.9% of cases and within 6° in all cases.
The toric multifocal IOL was more predictable than the relaxing incisions in addressing the preoperative corneal astigmatism, Maurino said.
“The advantage of correcting astigmatism with toric lenses is that the astigmatism correction is independent from wound healing, unlike peripheral corneal relaxing incisions, and hence it is more predictable,” he said.
Patients were spectacle independent most of the time, with 52.9% of all patients requiring glasses only when reading for an extended time. – by Matt Hasson
Reference:
Gangwani V, et al. J Cataract Refract Surg. 2014;doi:10.1016/j.jcrs.2014.01.037.For more information:
Vincenzo Maurino, MD, is Consultant Ophthalmologist and Director of Cataract Service at Moorfields Eye Hospital and can be reached at Moorfields Eye Hospital, City Road, London EC1V 2PD, United Kingdom; email: vincenzo.maurino@moorfields.nhs.uk.Disclosure: Maurino has no relevant financial disclosures.