Design of an intraocular pressure curve protocol for use in dogs

Abstract

Summary:Objectives:To establish an intraocular pressure curve protocol that is safe for corneal health and determining if they detect harmful elevations of intraocular pressure outside normal clinic hours. To determine inter-user variability and if repeated measurements affect intraocular pressures.Methods: Dogs with glaucoma were included in the first part of the study in which intraocular pressures were measured using three protocols. Protocol 1 used applanation tonometry every two hours over 24h. Protocols 2 and 3 used applanation or rebound tonometry, respectively, and measured intraocular pressures every three hours over 30h. Sixty additional intraocular pressure curves from dogs with glaucoma and 20 from healthy dogs were then analysed for inter-user variability. Results:128 Intraocular pressure curves were determined in 30 dogs. Protocol 1 resulted in one ulcer in five pressure curve measurements, Protocol 2 in one ulcer in 62 pressure curves, and Protocol 3 in no ulcers in 61. Elevated intraocular pressures were detected on 61 occasions, of which 26 developed outside normal clinic hours. Sixty-one additional intraocular pressure curves revealed that repeated measurements had no effect on intraocular pressure. Assessors had a significant variability in righteye but not left-eye readings.Conclusions: Protocol 3, using rebound tonometry every three hours for 30hr is safe and identified elevated intraocular pressures outside normal clinic hours in 12/30 (40%) of patients that single intraocular pressure measurement during consultation hours would not have identified. Intraocular pressure curves may be recommended for clinical practice and glaucoma studies.

Effect of sedation with butorphanol on variables pertaining to the ophthalmic examination in dogs

“…Although a fluorescein test was not performed, slit examination did not detect epithelial changes that could have influenced tear stimulation. This is in agreement with previous investigations in dogs, which did not report corneal side effects of serial STT‐1 readings and rebound tonometry measurements …”

“…This is in agreement with previous investigations in dogs, which did not report corneal side effects of serial STT-1 readings 30,60,63 and rebound tonometry measurements. 57,65 In conclusion, the present study has shown that the sedative effect resulting from the intramuscular administration of 0.2 mg/kg of butorphanol was not associated with any change in the position of the globe and nictitating membrane, did not appear to influence the results of the basic tests of the neuro-ophthalmic examination, and did not modify basal tear secretion. The findings also suggest that the opioid can affect reflex tear production, IOP, and pupil size, which is in agreement with previous studies.…”

Rabbits with naturally occurring cataracts referred for phacoemulsification and intraocular lens implantation: a preliminary study of 12 cases

“…The prevalence of POH in rabbits is unknown. Three of the 13 operated rabbits in the present study had their IOPs measured for more than 12 h postoperatively using a previously described IOP‐curve protocol, and none developed POH during that time. The rest of the rabbits had very brief hospital stays (approximately 6 h), and none developed POH during that time.…”

“…The first three operated rabbits (P1‐P3) stayed overnight and underwent serial intraocular pressure (IOP) measurements to assess for postoperative hypertension (POH) following an established protocol . None of the three rabbits developed POH during that time.…”

Medical anti‐glaucoma therapy: Beyond the drop

“…Review of major clinical trials in humans suggests that the IOP variations themselves (versus simply the magnitude of the IOP increase) may be an independent risk factor for the progression of glaucoma 7 . Recently, Sanchez et al demonstrated that rebound tonometry every 3 hours for 30 hours found increased IOP in 40% of patients that a single IOP measurement during regular clinic hours would not have identified 8 . This suggests that treatment modalities that more consistently blunt short‐ and long‐term variability in IOP may improve patient outcomes.…”