An 80-year-old woman presented with bilateral cataracts and corneal astigmatism. Her BSCVA was 20/50 OU with a manifest refraction of -0.50+2.25x180 OD and -1.50+2.50x180 OS. Slit lamp examination revealed 3+ nuclear sclerotic cataracts, pseudoexfoliation syndrome, and poor dilation OU. Corneal topography showed regular astigmatism, the amount and orientation of which was in good agreement with that determined by refraction, keratometry, and IOLMaster measurements.
After discussing the surgical options, the patient chose to have cataract extraction with toric IOL implants. The 1st surgery (OS) was uncomplicated and a toric IOL was placed in the capsular bag. However, at the time of the 2nd surgery (OD), a 2 clock hour area of zonular dehiscence due to the pseudoexfoliation syndrome was noted. Since this could undermine the rotational stability of the lens as well as the long-term stability of the capsule-IOL complex, even with placement of a capsular tension ring, a toric IOL was not inserted into the capsular bag. Rather, a monofocal IOL was placed in the sulcus with the haptics oriented perpendicular to the area of missing zonules and the optic captured through the capsulorrhexis, and corneal relaxing incisions were performed.
The patient achieved 20/25 uncorrected vision in both eyes and was very happy. At 1 month postop, her refraction was plano+0.50x95 OD and -0.50+0.50x45 OS. Corneal topography demonstrated an overcorrection of the corneal astigmatism with some irregularity OD while the map was essentially unchanged OS.
Discussion:
This case illustrates several important points. Corneal astigmatism can be treated effectively at the time of cataract surgery with either toric IOLs or corneal relaxing incisions. There are advantages and disadvantages to each method; however, corneal relaxing incisions are less predictable (especially with higher levels of astigmatism) and can induce irregular astigmatism. Regardless of the surgical technique used to correct astigmatism, it is essential to have a backup strategy, which should be discussed with the patient beforehand. Specifically, the surgeon should calculate IOLs for the bag, sulcus, and anterior chamber positions, and when planning to use a toric implant it is also important to calculate the necessary relaxing incisions.