The increasing demand among cataract patients to minimize postoperative refractive error has made astigmatism correction a higher priority. It may not quite yet be a necessity but, to many, it’s certainly more than a luxury.
Currently, epidemiological evidence on the prevalence and severity of astigmatism before and after cataract surgery is limited and ineffective. To address this gap, a team of UK researchers conducted a large retrospective review of 110,468 eyes of patients older than 65 undergoing cataract surgery. They found that cataract patients carry a significant burden of preoperative astigmatism, which is not reduced after surgery with standard monofocal intraocular lens (IOL) implantation.
The researchers evaluated preoperative corneal astigmatism using the most recent keratometry measure within two years before surgery and, in eyes receiving standard monofocal IOLs, postoperative refractive astigmatism using the most recent refraction measure within two to 12 months after surgery. They then completed a power vector analysis to compare changes in the astigmatic 2D vector before and after surgery in the subgroup of eyes with both preoperative and postoperative astigmatism measurements. The team also assessed VA preoperatively and postoperatively.
They found that preoperative corneal astigmatism rates as follows:
After surgery, the refractive cylinder was available for 36% of eyes receiving standard monofocal IOLs; of these, 90% had postoperative astigmatism ≥0.5D and for 58% the figure was ≥1.0D. They add that VA worsened postoperatively with increased astigmatism.
The study concludes, “measures should be taken to improve visual outcomes of patients with astigmatic cataract by simultaneously correcting astigmatism during cataract surgery.”
|Day AC, Dhariwal M, Keith MS, et al. Distribution of preoperative and postoperative astigmatism in a large population of patients undergoing cataract surgery in the UK. Br J Ophthalmol. September 6, 2018. [Epub ahead of print].|