Purchase this article with an account.
Christian E. Song, Carlos G. De Moraes, Ilana Forchheimer, Tiago S. Prata, Celso Tello, Robert Ritch, Jeffrey M. Liebmann; Caution When Assessing Risk of Conversion to Glaucoma in Ocular Hypertensive Patients: the Role of Risk Variability Over Time. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5039.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate whether the risk of conversion to primary open angle glaucoma (POAG) among patients with ocular hypertension (OHT) varies significantly over time.
We reviewed the charts of untreated OHT patients seen in a glaucoma referral practice for a minimum of 60 months. Clinical variables collected at baseline and during follow-up included age, central corneal thickness (CCT), intraocular pressure (IOP), vertical cup-to-disc ratio (VCDR), and visual field pattern standard deviation (VFPSD). These were used to calculate the 5-year risk of conversion to POAG at each follow-up visit using the OHTS calculator (http://ohts.wustl.edu/risk/calculator.html). We also calculated the risk of POAG conversion based on the fluctuation of measured variables over time assuming the worst (WCS; final age, highest PSD, lowest CCT, highest IOP, and highest VCDR) and best case scenarios (BCS, baseline age, lowest PSD, highest CCT, lowest IOP, and lowest VCDR) for each patient. Risk values (%) were plotted against follow-up time to generate slopes of risk change over time.
We included 28 patients (56 eyes) followed for a mean of 97.9±18.3 months. The mean 5-year risk of conversion for each patient ranged from 10.6% to 24.1% during follow-up (p<0.01). The mean slope of risk change over time was 0.4±0.8% increase/year. The mean slope for patients who reached a POAG endpoint was significantly greater than for those who did not (1.3±0.7 vs. 0.03±0.5%/yr, p<0.01). In each patient, the mean risk of POAG conversion increased almost 10-fold when comparing the WCS with the BCS (45.1% vs. 5.0%, p<0.01).
The estimated 5-year risk of conversion to POAG among untreated OHT patients can vary significantly during follow-up, with a trend to increase over time. Within the same individual, the estimated risk can vary almost 10-fold based on the expected variability of IOP, CCT, VCDR and VFPSD. A single risk calculation measurement may not be sufficient for accurate risk assessment and treatment decision.
This PDF is available to Subscribers Only