A variety of refractive combinations can be seen after LASIK, but the most common are myopic patients getting more myopic and hyperopic patients getting more hyperopic.5,6 A very small group of patients presented with increasing astigmatism. Younger myopic patients can become more myopic with age. Treating myopic patients’ residual myopia is usually straightforward.
It is important to use corneal tomography, such as Oculus Pentacam, to assure corneal stability and thickness. Most surgeons perform photorefractive keratectomy (PRK) over the existing LASIK flap rather than lift the flap. This greatly reduces the risk of an epithelial ingrowth.
Patients who are in their 50s and become more myopic often have lenticular changes even though they still correct to 20/20. A referral to the operating surgeon for corneal tomography can be very informative. The Scheimpflug image of the lens, captured by the Pentacam, can show if the patient has a subtle clouding of the crystalline lens.
This imaging is very helpful in explaining why more corneal surgery is likely not in the patient’s best interest. With the advancement of multifocal and intraocular lenses, a clear lens extraction is a consideration for these patients.
Results of hyperopic LASIK reveals fewer patients achieve 20/20 vision without correction, but these patients can still be some of the happiest.7 When hyperopic patients become more hyperopic, it can be the result of several factors, including decreased accommodation and increased hyperopia and/or epithelial hyperplasia.8 None of these makes me excited to perform more corneal surgery.
The corneal epithelium does a good job of filling in any irregularity on the corneal surface, and in this case, it works against our laser vision correction treatments for hyperopic patients. Hyperopic LASIK removes a trough of tissue in the mid-periphery of the corneal stroma, resulting in the central cornea becoming relatively steeper.9 In hyperopic PRK, epithelial cells fill
-in this trough, which negates the effect of the treatment. This also happens in hyperopic LASIK, albeit to a lesser extent.
Treatment options for these patients include:
• Clear lens extraction
• Contact lenses