MAR 05, 2014
This retrospective study found that 10 percent of all eyes with a cataract had an opposite-axis difference in addition to more than 1 D of both corneal and internal astigmatism. In these cases, surgical techniques to reduce corneal astigmatism, such as implantation of a toric IOL, are recommended to increase patient satisfaction.
Patients with significant latent lenticular astigmatism cancelling out corneal astigmatism after cataract surgery for the first time absolutely deserve toric implants. I wish insurance companies were smart enough to distinguish this group from those who are simply motivated to be spectacle-free. I often give away my part of the fee for toric IOLs for those with this condition who can’t afford them.
The authors reviewed the charts of 180 patients who underwent cataract surgery. Preoperative refractive, corneal and internal astigmatism were measured using a wavefront analyzer and retrospectively analyzed.
On-axis was defined as an axis difference between corneal and internal astigmatism of 180 ± 10 degrees. Opposite-axis was defined as an axis difference between corneal and internal astigmatism of 90 ± 10 degrees. The remaining cases were defined as oblique-axis.
Corneal and internal astigmatic vectors showed a tendency to have the opposite direction. An on-axis difference was seen in 10 percent of patients (18 eyes), oblique-axis in 69.4 percent (125 eyes) and opposite-axis in 20.6 percent (37 eyes).
Of all eyes, 10 percent had an opposite-axis difference with more than 1 D of both corneal and internal astigmatism. The percentage of eyes with an opposite-axis difference between corneal and internal astigmatism had a tendency to increase as corneal and internal astigmatism increased (P = .030 and P = .003, respectively).
The authors note that 46.1 percent of these patients would have been potential candidates for a toric IOL if corneal astigmatism of more than 1 D was considered as an indication for surgical techniques to reduce corneal astigmatism (such as a toric IOL). If greater than 1.50 D was considered, 22.2 percent of the patients in this study would be potential candidates.