This article is more than 5 years old. Information may no longer be current.
Researchers recommend frequency for perimetry
Click Here to Manage Email Alerts
Researchers used computer simulation and mean deviation trend analysis to recommend two baseline visual field tests, then one every 6 months in the first year for newly diagnosed glaucoma patients.
They evaluated the specificity of clinical monitoring protocols and time required to detect visual field progression by standard automated perimetry in patients with glaucoma.
While SAP is the gold standard for detecting progressive damage in glaucoma, timely and accurate detection of changes, which is crucial to make decisions on therapy, is made difficult by the inherent variability of this testing method, the authors stated
In this study, 1,072 eyes of 665 glaucoma patients with five or more visual field tests performed over a period of 2 to 5 years were included. A total of 8,240 visual field tests were analyzed to derive the longitudinal measurement variability of standard automated perimetry (SAP) mean deviation (MD) using linear regressions. By computer simulation, real-world visual field data were then reconstructed to evaluate the time required to detect progression for various rates of visual field loss and different monitoring schedules.
The authors concluded that two reliable visual field tests at baseline followed by one test every 6 months within the first year of follow-up may be a reliable and cost-effective monitoring schedule for newly diagnosed patients. It was also demonstrated that additional testing does not proportionally decrease the time required to detect progression and might, on the other hand, increase the chance of false-positive detections. The gain provided is, in fact, too small to compensate for the increased burden on patients, clinics and health care systems.
“It should be noted, however, that patients with more advanced visual field loss or presenting with mild damage at a younger age may require more frequent visual field testing in clinical practice,” the authors stated. – by Michela Cimberle
Disclosure: Wu reports no financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
Perspective
Back to Top
Scott Anthony, OD, FAAO
Detection of glaucoma progression is often confounding and can take months, if not years. to verify. Rarely do we witness abrupt structural and functional changes that declare glaucoma progression – with the possible exception of a new optic disc hemorrhage. Rather, we are dealing with incremental changes of the optic nerve, retinal nerve fiber layer and visual field over time.
Wu and colleagues help us understand what it will take to reach a timely and accurate assessment for verifying visual field progression. They did not use guided progression analysis (Carl Zeiss Meditec), the event-based software program that helps find visual field progression for each point in the visual field. Instead, they looked at the change in mean deviation over time, a trend-based analysis of visual field status. In practice, I use both sets of data to help determine if visual field progression is present.
Also highlighted is the importance of two good baseline visual fields within the first year of diagnosis, with semiannual follow-up testing once management commences, which continues until progression is ruled out. This study should help clinicians formulate a more prescribed and accurate pattern of glaucoma care.
Collapse
Wu Z, et al. Ophthalmology. 2017; doi: http://dx.doi.org/10.1016/j.ophtha.2017.01.027
Click Here to Manage Email Alerts