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Cataract patient with prior RK, LASIK desires distance correction
 John A. Hovanesian |
 Joseph G. Heinrich |
A 49-year-old patient had a history of radial keratotomy in both eyes in 1987. He developed a hyperopic shift in his right eye several years later and had LASIK to improve distance vision in 1999. More recently, the patient developed a cataract in the right eye. The patient desired spectacle independence for at least distance vision.
Our approach
To choose the power of the patient’s lens implant, in the surgeon’s office we measured the effective corneal power using the average axial powers from corneal topography. We also compared the spherical equivalent of his manifest refraction to that of his over-refraction while wearing a gas-permeable contact lens of known anterior curvature. These data were used to calculate his desired IOL power (targeting emmetropia) using the Holladay II, Hoffer Q and Haigis formulas available on the website of the American Society of Cataract and Refractive Surgery (www.ascrs.org).
Surgical outcome
One month after uneventful surgery, the patient’s right eye had the following refraction: -2.00 D, -1.00 D, axis 013 correcting to 20/25. There was mild opacity of the posterior lens capsule. The patient complained of limited distance vision.
I plan to do a PRK (with mitomycin C), and the patient is likely to do quite well. We generally do a Nd:YAG capsulotomy prior to PRK because of the small but real chance of the capsulotomy shifting the lens’ position and efficacy.
Take-home points
Patients with prior refractive surgery deserve special consideration when cataract surgery is being considered because of the challenge in obtaining precise corneal power measurements in patients with previously-altered corneas. RK is particularly difficult in this respect, and when myopic RK is combined with subsequent hyperopic LASIK, surprises often occur. To avoid disappointment, patients should know about the possible need for “enhancement” before cataract surgery is performed.
Because this patient’s cornea did not have a high degree of irregular astigmatism, photorefractive keratectomy with mitomycin was a reasonable option, considering he had a history of multiple procedures.
In more routine cases where enhancement is needed, some surgeons prefer to perform LASIK, implant piggyback IOLs or even perform mini-RK. All of these can achieve a satisfactory result, and some form of enhancement is generally necessary when residual refractive error is greater than +/-0.5 D.
- Joseph G. Heinrich, OD, can be reached at 32241 Camino Capistrano, Suite A-101, San Juan Capistrano, CA 92675; (949) 661-3669; joehein@pacbell.net.
- John A. Hovanesian, MD, FACS, is a member of the Primary Care Optometry News Editorial Board. He can be reached at Harvard Eye Associates, 24401 Calle De La Louisa, Suite 300, Laguna Hills, CA 92653; (949) 951-2020; fax: (949) 380-7856; drhovanesian@harvardeye.com.