Intraocular pressure measurements using dynamic contour tonometry after laser in situ keratomileusis.
OBJECTIVE
Thinning of the corneal stroma by laser in situ keratomileusis (LASIK) results in inaccurate low intraocular pressure (IOP) readings by Goldmann applanation tonometry (GAT). Dynamic contour tonometry (DCT) is a novel measuring technique, designed to measure IOP largely independent of corneal thickness and curvature. The purpose of this study was to compare IOP measurements using GAT and DCT in eyes undergoing LASIK for correction of myopia.


METHODS
In a prospective, single-center study, central corneal thickness (CCT) and IOP were measured in patients undergoing first-time LASIK for myopia. IOP was measured before and after surgery using GAT and DCT. The untreated contralateral eyes served as paired controls.


RESULTS
There was good concordance between the two tonometers in 62 normal eyes before LASIK. Corneal ablation of 90.0 +/- 49.18 micro m (median +/- SD) reduced IOP readings as measured by GAT by 3.0 +/- 1.9 mm Hg (P < 0.001). In contrast, no significant change in IOP readings was recorded by DCT (-0.2 mm Hg +/- 1.5 mm Hg, P = 0.30). There was no change in IOP in the untreated control eyes as measured by GAT and DCT.


CONCLUSIONS
Significant decreases in IOP were recorded by GAT after LASIK for myopia. Measurements by DCT, however, did not reveal any significant changes in IOP.
Kaufmann
Claude
C
Department of Ophthalmology, University of Zurich, Zurich, Switzerland. claude.kaufmann@freesurf.ch
Bachmann
Lucas M
LM
Thiel
Michael A
MA
D000328:Adult; D003315:Cornea / Q000601:surgery*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D020731:Keratomileusis, Laser In Situ; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011446:Prospective Studies; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000379:methods / Q000592:standards*