(RxWiki News) Glaucoma doesn't progress overnight. It's usually a steady deterioration. That's why frequent visual field tests may aid in detecting progression of the disease sooner.
Getting visual field tests to check peripheral vision twice a year means doctors can catch sight worsening sooner, and take action to treat it more quickly.
"Glaucoma patients should get a 'field of vision' test twice a year."
Dr. Kouros Nouri-Mahdavi and his colleagues from the Jules Stein Eye Institute at the University of California wrote that estimating the rates of progression could help identify patients progressing at a faster pace who are at serious risk for developing visual disability during their lifetime. Those patients could then receive more aggressive treatment or more frequent follow up visits.
Researchers examined data from the Advanced Glaucoma Intervention Study. They chose to review information about 468 eyes of 381 patients between the ages of 35 and 80. All of the patients had primary open-angle glaucoma that was no longer controlled well by medical treatment. Open-eye glaucoma, the most common type, is often hereditary and occurs when eye pressure builds slowly over time. It mostly affects those over the age of 50.
Participants had 10 or more visual field exams with at least three years of follow up. In addition to compiling all visual field tests, investigators assembled a second set of data by deleting every other visual field test starting in the second year of follow up. This allowed researchers to compare the two sets of data to examine the proportion of eyes that progressed and the amount of time it took.
Patients were followed for between 3.2 years and 13 years with a median of 9 years. Researchers found that the data that included all visual field tests was most likely to detect progression, including improvements that were noted in some patients.
Dr. Christopher Quinn, an optometrist with Omni Eye Services, said the question of how many visual field tests per year is appropriate is complex. He said some glaucoma patients may be best suited receiving testing every few years, while others need them monthly. An average number is meaningless to an individual patient, he said.
"Each patient with glaucoma should be managed on an individual basis since the patients risk factors, the degree of existing damage and the individual’s rate of progression all determine the appropriate frequency of follow-up and visual field testing," Dr. Quinn said. "It is pretty easy to conclude that more frequent testing is more sensitive in detecting progression. More frequent visual field testing may also lead to false positives resulting in more aggressive treatment that may not be necessary.
The research was published in Archives of Ophthalmology, from the Journals of the American Medical Association.