Many patients who have undergone LASIK, PRK, RK, or conductive keratoplasty are now developing cataracts and are interested in premium IOL implantation. The catch-22 is this is arguably the most-motivated patient population for spectacle-independence, and yet, their IOL calculations are the most unpredictable, according to Dr. Starr.
“The ASCRS [American Society of Cataract and Refractive Surgery] Post-Refractive IOL Calculator is a godsend for these patients,” he said. “Over time, it has become more and more accurate, and the range of IOL suggestions are much tighter now. I am much more comfortable now targeting plano than previously when I would target some myopia.”
Other tools—such as intraoperative aberrometry and light-adjustable IOLs—have helped to improve refractive outcomes in these patients.
Dr. Starr advised ruling out post-LASIK ectasia before implanting a toric IOL, with the presumption that a high degree of corneal astigmatism is present. He also recommended preoperatively assessing candidacy for a possible laser vision correction touch-up in the event of a refractive IOL “surprise.”
When facing patients with keratoconus, pellucid marginal corneal degeneration, post-LASIK ectasia, post- keratoplasty (PK), and post-deep anterior lamellar keratoplasty, the rule of thumb is if patients can successful wear a rigid gas permeable or scleral lens postoperatively, a toric IOL should not be implanted.
However, a toric IOL is a consideration if patients are contact lens-intolerant, have acceptable spectacle-corrected vision, and have a fairly regular central cornea over the long term as in older patients or after a crosslinking procedure.
A toric IOL is also a reasonable choice in post-PK eyes in which there is a low risk of graft failure and the need for another PK, Dr. Starr explained.