Managing Post-LASIK Corneal Irregularity
BY Gregory DeNaeyer, OD, FAAO
Million of patients have undergone laser-assisted in situ keratomileusis (LASIK) treatment to correct refractive error to lessen dependency on glasses or contact lenses. Unfortunately, a small percentage of these patients develop corneal irregularity that decreases their best-corrected visual acuity with standard correction.
Corneal irregularity following LASIK can result from a variety of complications: surgical complications such as partial flap, epithelial ingrowth, a flap wrinkle or scar following post-surgical trauma (Figure 1), and ectasia. The anterior corneal flap that is made during the procedure specifically puts patients at risk for these complications.
Many of these post-LASIK patients who have corneal irregularity have the potential to dramatically improve their visual acuity with GP lenses. However, it’s important to consider a few points before starting the fitting process.
Psychological These patients need extra education on why they need a GP lens and what they should expect with lens wear. Keep in mind that these patients underwent LASIK to achieve functional vision without contact lenses. Also, many of these patients will not have had previous experience with GP lenses.
Corneal Shape Patients after myopic LASIK will have oblate corneas, and patients after hyperopic LASIK will have prolate corneas.
Knowing the patient’s corneal geometry is essential when considering lens design. For example, a patient with an oblate cornea will be better fit with a GP lens design that incorporates reverse geometry. Performing corneal topography is recommended to confirm and grade corneal geometry. This is especially important if the patient has severe irregularity, which can dramatically alter the corneal shape.
Figure 1. An example of post-surgical trauma.
Blanchard’s RSS (Refractive Surgery Specific) corneal GP lens has a reverse geometry design that can also be modified using ACT (Asymmetric Corneal Technology) to independently adjust the inferior quadrant. Additionally, the RSS lens can be manufactured with Reclaim HD optics if the patient is presbyopic.
Valley Contax’s LASIK Near design and Art Opticals’ CLASIKcn are reverse geometry designs with multifocal optics. Realistically, multifocal optics may optimally function best if the post-LASIK patient has only mild irregularity without scarring.
Corneal Ectasia The true incidence of corneal ectasia following LASIK is unknown (ASCRS, 2003), but when it occurs, the results can be devastating to the patient. Generally, you can manage these patients like keratoconus patients: corneal GP lenses for mild-to-moderate cases, and hybrid and scleral designs for moderate-to-severe ectasia. Corneal cross-linking may be considered for cases of progressive ectasia.
Post-LASIK corneal irregularity can significantly reduce patients’ uncorrected acuity, but for most of these cases, a well-fit GP lens can return patients to normal visual function. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #205.
Dr. DeNaeyer is the clinical director for Arena Eye Surgeons in Columbus, Ohio, and a consultant to Visionary Optics, B+L, and Aciont. You can contact him at gdenaeyer@ arenaeyesurgeons.com.