SEATTLE, Washington — Researchers can use 3 significant predictive factors to figure out which patients with open-angle glaucoma are at greatest risk for rapid progression and visual field loss.
“We looked at who had fast visual progression to see how they did and if there were any clinical or demographic factors associated with rapid progression,” Meera Ramanathan, MD, from the Jules Stein Eye Institute at the University of California in Los Angeles, told Medscape Medical News.
Dr. Ramanathan and colleagues assessed 767 eyes from 566 participants in the Advanced Glaucoma Intervention Study. Patients with open-angle glaucoma who had a worse mean deviation to their visual field, a greater vertical cup-to-disc ratio at baseline, or who were older were significantly more likely to see a rapid decay of their visual field.
The team used multiple regression analysis to compare the 222 eyes that progressed rapidly with the 545 eyes that progressed slowly.
Rapid progression was defined as a rate of visual field changes of at least 36% per year.
The findings were presented in a poster session that garnered a lot of attention here at the Association for Research in Vision and Ophthalmology 2013 Annual Meeting.
Table. Baseline Predictors of Rapid Glaucoma Progression
|Predictor||Odds Ratio||95% Confidence Interval||P Value|
|Worse mean deviation||1.12||1.09–1.16||<.0001|
|Greater vertical disc-to-cup ratio||1.23||1.09–1.39||.001|
Factors that pointed to an increased risk for progression, but were not statistically significant, included being male (odds ratio [OR], 1.37; 95% confidence interval [CI], 0.97 – 1.93; P = .071) and having worse visual acuity at baseline (OR, 1.93; 95% CI, 0.92 – 3.99; P = .077).
George Chiou, PhD, from the Institute of Ocular Pharmacy at the Texas A&M University System in Houston, who was asked by Medscape Medical News to comment on the study, said that this information is very useful for diagnosis and for monitoring progression of the disease.
“Antiglaucoma drugs can be prescribed and adjusted more precisely as a result,” he noted.
Shuchi Patel, MD, an ophthalmologist from Loyola University Medical Center in Maywood, Illinois, had a similar reaction. “The question of who will progress is of paramount importance. The rate of glaucoma progression determines the frequency of visits, therapeutic options, goals, and when to proceed with surgical intervention. Currently, physicians use a combination of functional and structural tests for monitoring for progression, as well as some personalized algorithms, but these are not perfect or altogether scientific.”
We might be getting a peek into a crystal ball.
Dr. Patel added that “this study is very clinically relevant because if we could come up with a proven list of risk factors that indicate high risk for progression, we might be getting a peek into a crystal ball.”
Rei Sakata, MD, from the University of Tokyo in Japan, told Medscape Medical News that this study “confirms the significance of the evaluation of the optic disc [structure] and visual field [function] at the initial visit, although there seems to be a variety of glaucoma progression-related factors.”
For instance, “there is a different composition rate of glaucoma by race,” she explained. Normal-tension glaucoma is the most common presentation in Asian patients. In addition, open-angle and normal-tension glaucoma may have different mechanisms, related systemic and ocular factors, and treatment strategies.
Dr. Sakata was principal investigator on a study assessing the factors that contribute to visual field loss in patients with normal-tension glaucoma (J Glaucoma. 2013;22:250-254).
It would have been helpful if the researchers had included some predictors of visual field progression in the regression analyses, “such as central corneal thickness and blood pressure,” Dr. Sakata said. However, “they did identify some risk factors for glaucoma progression, which is a great service.”
Point-wise exponential regression analysis facilitated the classification of patients into the fast and slow progression groups. This strategy to detect the visual field rate of decay in patients with glaucoma was validated in a previous study by Joseph Caprioli, MD, and colleagues (Invest Ophthalmol Vis Sci. 2012;53:5403-5409). Dr. Caprioli, also from the Jules Stein Eye Institute, was part of the current study.
Dr. Ramanathan and her colleagues also performed a statistical “cross validation” of their findings. They sampled two thirds of the study population and identified rapidly progressing patients using the predictors from their logistic regression. They then identified coefficient estimates and applied them to the remaining one third of participants. After repeating this calculation 1000 times, they determined an average area-under-the-curve value, which showed that their factors carry a 0.72 predictive value for progression of glaucoma.
This study was not funded by outside sources. Dr. Ramanathan, Dr. Patel, and Dr. Sakata have disclosed no relevant financial relationships. Dr. Caprioli reports being a consultant and receiving financial support from Allergan. Dr. Chiou is chief scientific officer of MacuCLEAR, Inc, a clinical-stage specialty pharmaceutical company focused on vascular disorders of the eye.
Association for Research in Vision and Ophthalmology (ARVO) 2013 Annual Meeting: Abstract D0163. Presented May 7, 2013.