Tonopen versus goldmann applanation tonometer for intraocular pressure evaluation after excimer laser photorefractive keratectomy

Purpose: Relative flattening and thinning of the central cornea following excimer laser photo refractive keratectomy (PRK) may contribute to a falsely low intraocular pressure (IOP) reading by Goldmann applanation tonometry (GAT) Therefor, we examined in this study IOP measurement by Tonopen 2 tonometer versus GAT in post PRK patients Materials and Methods: IOP in 18 post PRK patients (PRK was performed in one eye only) was measured in both eyes by a masked observer by GAT followed by Tonopen 2 tonometer IOP evaluation was performed 2 to 18 months following PRK (6 6±5 I mo) Corneal curvature and thickness were evaluated Results: The results are listed in the following table A IOP (mmHg) Refraction (PostVPre PRK) ratio (Tonopen-GAT) (S.E. D) Corneal Corneal curvature thickness Post PRK eyes 1.79±1.08 0.13±0.86 0.91±0.03 0.86+0.04 (p=0.016) Fellow eyes (Control) 0.19±3.06 -5.1±2.02 1.00±fl.01 1.00±0.04 Conclusions: 1OP is lower in post PRK patients when measured by GAT in comparison to Tonopen by approximately 1 8 mmHg IOP is almost similar in the fellow eyes of these patients when measured by GAT and Tonopen None.