Change in intraocular pressure measurement 2 years after myopic laser-assisted subepithelial keratectomy

To evaluate intraocular pressure (IOP) measurements 24 months after laser-assisted subepithelial keratectomy (LASEK) with 3 tonometry methods-Goldmann applanation tonometry (GAT), Pascal dynamic contour tonometry (DCT), and applanation resonance tonometry (ART)-and to compare them with measurements taken preoperatively and 3 and 6 months postoperatively.

Department of Ophthalmology, Umeå University, Umeå, Sweden.

Prospective randomized single-center.

One randomized eye per person from myopic healthy individuals who had LASEK was included. Visual acuity, central corneal thickness (CCT), corneal curvature, and IOP were measured at all time points. Six IOP measurements were performed per method, with a 5-minute lapse between methods.

The study evaluated 38 eyes. Two years after LASEK, dynamic ART was the only method that did not measure significantly lower IOP than before LASEK (mean -0.2 mm Hg ± 1.6 [SD]). The greatest difference was with GAT (mean -1.9 ± 1.7 mm Hg) followed by static ART (mean -1.2 ± 1.6 mm Hg) and then DCT (mean -0.9 ± 1.3 mm Hg). All methods measured significantly lower IOP at 3 months and 6 months.

Dynamic ART, which analyses IOP measurement during indentation, showed no significant difference in measured IOP after 24 months. The convex tip of the ART device and the continuous sampling of data during corneal indentation seem to be factors in why dynamic ART was less affected by corneal properties and therefore more suitable for IOP measurement in LASEK-treated eyes, although this must be confirmed in larger trials.