Abstract
Purpose :
A single measurement of intraocular pressure (IOP) in a glaucoma clinic is suboptimal due to diurnal variations in IOP. The aim of our study is to evaluate the value of short-protocol office hour phasing in the management of patients in a glaucoma clinic.
Methods :
In this retrospective cohort study, the clinical records of 48 consecutive patients who attended the glaucoma specialist outpatient clinic of St Thomas’ Hospital for phasing between June and October 2017 were reviewed. IOP was measured using Goldmann applanation tonometry, at hourly intervals from 0900 to 1600 hours, or until a peak in IOP was detected, whereby phasing was terminated early. Changes in diagnosis and management based on phasing results were evaluated.
Results :
The main indication for phasing was the presence of a suspicious optic disc (72.9%). In majority of patients (72%), a peak IOP was identified between 9-11am, and phasing was required for mean duration of 4.4 ± 1.5 hr. The mean peak IOP obtained before phasing was 18.9 ± 4.8 mmHg, compared to a mean peak IOP during phasing was 20.4 ± 4.4 mmHg (p=0.0145). 33.3% of patients had a change in diagnosis after phasing. Out of 31 patients who were glaucoma suspects, 8 (25.8%) were diagnosed as primary open angle glaucoma (POAG), 2 (6.5%) as normal tension glaucoma (NTG), and 4 (13%) as ocular hypertension (OHT). The diagnosis of NTG was changed to POAG in 2 patients. Ocular hypotensives were commenced in 21 (43.8%) patients after phasing. In this group of patients, a larger IOP fluctuation during phasing (3.1 ± 1.4 mmHg vs 4.6 ± 2.3 mmHg, p=0.01) was obtained compared to patients who remained without treatment.
Conclusions :
Phasing IOP for just 4.4 hr refined the diagnosis in 33.3% of our patients, and led to an initiation of treatment in 43.8% of patients. Short protocol office hour phasing is effective in diagnosis and management of patients in a glaucoma clinic.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.