NONCONTACT TONOMETRY IN PATIENTS THAT UNDERWENT PHOTOREFRACTIVE KERATECTOMY

To determine the accuracy of non-contact tonometry in patients with co rneas thinned by photorefractive keratectomy, the authors measured the intraocular pressure with a non-contact tonometer and the corneal thi ckness with an ultrasonic pachymeter in 47 patients before and 9 month s after photorefractive keratectomy. The patients were divided into th ree groups according to the degree of treatment: group I between 1 and 5 diopters (14 eyes), group II between 6 and 10 diopters (18 eyes), g roup III between II and 15 diopters (15 eyes). In the first group of p atients mean intraocular pressure was 16.1 (+/-3.85) mm Hg before surg ery, and 13.2 (+/-3.14) mm Hg after surgery with a significant differe nce (p = 0.0027). In the second group of patients mean intraocular pre ssure was 16.0 (+/-4.13) mm Hg before surgery and 13.0 (+/-3.0) mm Hg after surgery with a significant difference (p = 0.0045). In the third group of patients mean intraocular pressure was 17.7 (+/-3.8) mm Hg b efore surgery and 12.4 (+/-2.6) mm Hg after surgery, with a significan t difference (p = 0.0005). In conclusion, according to our results, no n-contact tonometry needs a correcting factor for measuring the intrao cular pressure in patients that underwent photorefractive keratectomy, related to the degree of refractive treatment.