Non-contact tonometry in patients that underwent photorefractive keratectomy

Ophthalmologica. 1997;211(6):341-3. doi: 10.1159/000310825.

Abstract

To determine the accuracy of non-contact tonometry in patients with corneas thinned by photorefractive keratectomy, the authors measured the intraocular pressure with a non-contact tonometer and the corneal thickness with an ultrasonic pachymeter in 47 patients before and 9 months after photorefractive keratectomy. The patients were divided into three 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), group III between 11 and 15 diopters (15 eyes). In the first group of patients mean intraocular pressure was 16.1 (+/-3.85) mm Hg before surgery, and 13.2 (+/-3.14) mm Hg after surgery with a significant difference (p = 0.0027). In the second group of patients mean intraocular pressure 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 before surgery and 12.4 (+/-2.6) mm Hg after surgery, with a significant difference (p = 0.0005). In conclusion, according to our results, non-contact tonometry needs a correcting factor for measuring the intraocular pressure in patients that underwent photorefractive keratectomy, related to the degree of refractive treatment.

MeSH terms

  • Adult
  • Cornea / physiopathology*
  • Cornea / surgery
  • Female
  • Follow-Up Studies
  • Humans
  • Intraocular Pressure / physiology*
  • Lasers, Excimer
  • Male
  • Middle Aged
  • Myopia / physiopathology*
  • Myopia / surgery
  • Photorefractive Keratectomy*
  • Refraction, Ocular
  • Reproducibility of Results
  • Tonometry, Ocular / methods*