Tono-Pen versus Goldmann tonometry after excimer laser photorefractive keratectomy.
OBJECTIVE
To compare intraocular pressure (IOP) measurements by the Tono-Pen 2 tonometer and Goldmann applanation tonometer (GAT) in post-photorefractive keratectomy (PRK) patients.


METHODS
Refractive Surgery Center, Assaf Harofeh Medical Center, Zerifin, Israel.


METHODS
In 18 patients, IOP was measured by GAT and then by Tono-Pen 2 tonometer 2 to 18 months following PRK (mean 6.6 months +/- 5.1 [SD]). Photorefractive keratectomy had been performed in 1 eye of each patient; the fellow eyes served as controls. Corneal curvature and thickness were evaluated. Ten of the 18 patients were treated with topical steroids.


RESULTS
In the post-PRK eyes, mean GAT IOP was 1.8 +/- 3.1 mm Hg lower than mean Tono-Pen IOP (P = .012); there was no significant IOP difference in the control (fellow) eyes. In steroid-treated post-PRK eyes, mean GAT IOP (12.2 mm Hg) was 2.2 +/- 1.3 mm Hg lower than mean Tono-Pen IOP (14.4 mm Hg) (P = .0007). Mean Tono-Pen IOP in steroid-treated post-PRK eyes was 4.3 +/- 3 mm Hg higher than in the fellow eyes (P = .0014); mean GAT IOP was only 2.3 +/- 3.5 mm Hg higher (P = .04). In post-PRK eyes without topical steroid treatment, mean GAT IOP was 2.0 +/- 1.18 mm Hg lower than in the fellow eyes (P = .001); there was no significant difference in Tono-Pen IOP. There was a negative correlation between the difference in IOP values (Tono-Pen minus GAT) and corneal curvature in post-PRK eyes (r = 0.76, P = .0108, n = 15).


CONCLUSIONS
The Tono-Pen tonometer appeared to be less affected than the GAT by the relative flattening, thinning, and anterior stromal decreased rigidity of the central cornea that occur following PRK. Post-PRK steroid-induced IOP elevation may be masked by the artifactual decrease in GAT IOP.
Levy
Y
Y
Department of Ophthalmology, Assaf Harofeh Medical Center, Zerifin, Israel.
Zadok
D
D
Glovinsky
Y
Y
Krakowski
D
D
Nemet
P
P
D000328:Adult; D003315:Cornea / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000601:surgery; D018903:Photorefractive Keratectomy; D011182:Postoperative Care; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014065:Tonometry, Ocular / Q000379:methods*