The preoperative evaluation of patients considering refractive surgery is presented in detail in Chapter 2. Table 5-1 lists relative contraindications to photoablation.
Special Considerations for Surface Ablation
In general, any condition that significantly delays epithelial healing is a relative contraindication to surface ablation. Although keloid scar formation was listed as a contraindication to PRK in FDA trials, 1 study found that African Americans with a history of keloid formation did well after PRK, and keloid formation is no longer considered a contraindication to surface ablation or LASIK. Historically, patients taking isotretinoin or amiodarone hydrochloride were excluded from undergoing excimer laser procedures, although there is little evidence that these drugs adversely affect laser keratorefractive outcomes.
Table 5-1 Relative Contraindications to Excimer Laser Photoablation
Patients with epithelial basement membrane dystrophy (EBMD) are better candidates for surface ablation than for LASIK because surface ablation may be therapeutic, reducing epithelial irregularity and improving postoperative quality of vision while enhancing epithelial adhesion. In contrast, LASIK may cause a frank epithelial defect in eyes with EBMD, especially when performed with a mechanical microkeratome.
Any patient undergoing excimer laser photoablation should have a pachymetric and topographic evaluation (see Chapter 2). Younger patients and patients with thin corneas, low predicted residual stromal bed (RSB) thickness, or irregular topography may be at increased risk for the development of ectasia with LASIK. As such, these patients may be better candidates for surface ablation. Patients with subtle topographic pattern abnormalities need to be evaluated on a case-by-case basis. In some circumstances, patients who are stable may be offered surface ablation but with a clear acknowledgment, as well as a signed informed consent form, that they understand there may still be a risk of progression to corneal ectasia.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.