A woman aged 47 years underwent radial keratotomy 22 years ago. Her uncorrected vision was good for 5 years until she started experiencing progressive hyperopic astigmatism leading to extreme fluctuation and loss of correctable vision. She underwent a procedure combining corneal ring segments (Intacs, Addition Technology Inc.) with interrupted suture closing of her RK incisions.
The patient was referred to the Duke Eye Center, Duke University, Durham, NC, for problems associated with eight-incision RK performed in both eyes 22 years ago. By history, she recalled having satisfactory vision after surgery for approximately 5 years before progressive hyperopic astigmatism developed. She required several changes in spectacles, eventually leading to both spectacle and contact lens intolerance and a loss of correctable vision to 20/80 in her right eye despite using a rigid contact lens. She had no pertinent medical or ocular history other than prior RK.
Discussion and diagnosis
RK was a popular refractive surgical procedure for myopia before the advent of photoablative options. Although RK worked well for most patients with low to moderate levels of myopia, some patients experienced myopic regression, and the vision of others was over-corrected, leading to progressive hyperopia and, in some cases, corneal instability and ectasia.1–3 Some estimates place the percentage of RK patients with progressive hyperopia as high as 34%.4
Treating progressive hyperopic astigmatism with ectasia in the post-RK patient presents several challenges. Treatment goals include re-establishing structural support in a profoundly weakened cornea while producing improving function by returning the cornea to an improved physiologic shape.
In milder cases, initial treatment usually consists of spectacle or contact-lens correction. These options become less successful in more advanced cases due to irregular astigmatism.