Online Photo Diagnosis

By William Townsend, OD, FAAO

The unusual fluorescein pattern seen in this photo resulted from a series of events that began 20 years ago. At that time, the patient was a 6.00D myope with severely dry eyes that made contact lens wear difficult and uncomfortable. She elected to undergo bilateral radial keratotomy (RK) and had an eight-incision procedure. Initially, she had an excellent surgical result but, over time, began to develop hyperopic astigmatism and significant diurnal fluctuations in refractive error.

Our patient tolerated this situation for years, but when corneal collagen cross-linking with riboflavin became a viable option, we referred her for this procedure. Her ultimate goal was to be able to wear contact lenses. She underwent the procedure, and over the next three months her refractive error stabilized, with minimal fluctuation noted over the latter segment of the postoperative period. We evaluated Duette (SynergEyes) lenses using the flattest base curve available. The patient was able to tolerate and see well with these lenses. The central area of concentrated fluorescein in the photo is from vaulting of the flattened corneal apex.

Radial keratotomy can result in a number of complications, including hyperopic shift; the 10-year Prospective Evaluation of Radial Keratotomy study showed a hyperopic shift of 1.00D or greater in 43 percent of patients during the 10-year postoperative period.¹ Other potential complications of RK include corneal ectasia,² infection,³ buttonhole flaps,⁴ and opening of the incision following eye rubbing.⁴ Patients who have variable refraction or progressive ectasia may benefit from collagen cross-linking to stabilize refractive error, but many will require additional correction with spectacles or contact lenses.

After six months, our patient continues to have good vision and comfort with the Duette lenses for distance correction and reading spectacles for near. Other approaches to managing post-RK patients include soft lenses and reverse-geometry GP lenses. A British study⁵ reported that the latter provided better visual acuity but that soft lenses were preferred for comfort.

References

1. Waring GO III, Lynn MJ, McDonnell PJ. Results of the Prospective Evaluation of Radial Keratotomy (PERK) study 10 years after surgery. Arch Ophthalmol. 1994;112:1298–1308.
2. Mazzotta C, Baiocchi S, Denaro R, Tosi GM, Caporossi T. Corneal collagen cross-linking to stop corneal ectasia exacerbated by radial keratotomy. Cornea. 2011;30:225–228.
3. Panda A, Das GK, Vanathi M, Kumar A. Corneal infection after radial keratotomy. J Cataract Refract Surg. 1998;24:331–334.
4. Stulting RD, Carr JD, Thompson KP, Waring GO 3rd, Wiley WM, Walker JG. Complications of laser in situ keratomileusis for the correction of myopia. Ophthalmology. 1999;106:13–20.
5. Hau SC, Ehrlich DP. Contact lens fitting following unsuccessful refractive surgery. Ophthalmic Physiol Opt. 2003;23:329–340.