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Two methods appear equally effective in correcting astigmatism
Eyes with preoperative astigmatism greater than 2.25 D achieved better results with a toric IOL compared with peripheral corneal relaxing incisions, study shows.
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CHICAGO – Performing peripheral corneal relaxing incisions and implanting a single-piece toric IOL appear equally efficacious in correcting astigmatism at the time of cataract surgery, according to study results.
 Jed T. Poll |
“Each modality has advantages and disadvantages,” Jed T. Poll, MD, said at the American Society of Cataract and Refractive Surgery annual meeting. “The question is do they have the same efficacy in astigmatic correction.”
He and colleagues at the Cullen Eye Institute in Houston conducted a 2-year retrospective study reviewing cases in which cataract surgery was combined with either a toric IOL or peripheral corneal relaxing incisions (PCRI). For standardization, all surgeries were performed by a single surgeon and a single-piece acrylic platform was maintained in the PCRI group. Patients with irregular astigmatism, corneal ectasia or other vision-limiting conditions and those who received a PCRI and a toric IOL in the same eye were excluded from the study, Dr. Poll said.
A total of 115 eyes received cataract surgery with PCRI and 77 eyes were implanted with an AcrySof Toric IOL (Alcon). Each modality was subdivided into three subgroups based upon the magnitude of preoperative keratometric astigmatism.
“The two treatment groups had similar preoperative data. However, there was a statistically significant difference in the magnitude of the keratometric astigmatism,” he said. Specifically, preoperative keratometric measurements averaged 2.1 D in the toric IOL eyes and 1.58 D in the PCRI eyes.
Results
The main outcome variables of the study were 1-month uncorrected distance visual acuity and residual postoperative refractive cylinder. In the toric group, the average postoperative cylinder was 0.42 D with 87% of patients achieving 20/40 or better uncorrected distance visual acuity. The PCRI group was comparable with an average postoperative cylinder of 0.46 D and uncorrected distance visual acuity better than 20/40 in 73% of patients, according to Dr. Poll.
The two treatment techniques provided similar astigmatic correction in the lower two subgroups (0.9 D to 2.25 D). However, in patients with preoperative astigmatism greater than 2.25 D, the toric IOL did show trends for improved results, he said.
In terms of postoperative vision, 87% of the eyes in this group that received a toric IOL had uncorrected distance visual acuity greater than or equal to 20/40, compared with 53% of those that received PCRI. This was a statistically significant difference between the groups (P = .026), Dr. Poll said.
Other postoperative parameters, including residual cylinder and percentage of eyes with less than 0.5 D of cylinder, showed trends for improved results with the toric lens but did not reach statistical significance, he said.
Recommendations
Based upon these results, Dr. Poll and colleagues have altered their cataract practice and offer the following recommendations for management of astigmatism at the time of cataract surgery: Eyes with about 1 D of cylinder or those eyes receiving a multifocal or accommodating IOL do well with PCRI; for eyes with 1 D to 3 D, use an appropriate toric IOL; and those eyes with greater than 3 D can achieve great results by implanting a toric IOL and performing a PCRI at the time of surgery or a few weeks postoperatively.
For more information:
- Jed T. Poll, MD, can be reached at Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030; 713-798-5945; e-mail: jpoll@bcm.tmc.edu. Dr. Poll has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.
- Jessica Loughery is an OSN Staff Writer who covers all aspects of ophthalmology.