The incidence of increased intraocular pressure (IOP) after surface ablation has been reported to range from 11% to 25%. Occasionally, the IOP may be quite high. In 1 study, 2% of patients had a postoperative IOP greater than 40 mm Hg. Most cases of elevated IOP are associated with prolonged topical corticosteroid therapy. Accordingly, postoperative corticosteroid-associated IOP elevations are more likely to occur after surface ablation (after which corticosteroid therapy may be used for 2–4 months to prevent postoperative corneal haze) or after complicated LASIK cases. Corticosteroid-induced elevated IOP occurs in 1.5%–3.0% of patients using fluorometholone but in up to 25% of patients using dexamethasone. The increase in IOP is usually controlled with topical IOP-lowering medications and typically normalizes after the corticosteroids are decreased or discontinued. Because of the changes in corneal curvature and/or corneal thickness, Goldmann tonometry readings after myopic surface ablation and LASIK are artifactually reduced (see Glaucoma After Refractive Surgery in Chapter 11). Several alternative techniques of measuring IOP have been suggested, but dynamic contour tonometry is the only technique shown to have sufficient reproducible accuracy in eyes after refractive ablation. In addition, with high IOP, fluid can collect in the flap interface and mask dangerously high IOPs, as applanation devices will artifactually measure the pressure of the fluid chamber created between the stroma and the LASIK flap. Other corticosteroid-associated complications that have been reported after surface ablation are reactivation of herpes simplex virus keratitis, ptosis, and cataracts.
Figure 6-3 Corneal topography findings indicating a decentered ablation.
(Courtesy of Roger F. Steinert, MD.)
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.