Optical devices have high rate of usage in patients with AMD

Issue: December 2012

Patients with age-related macular degeneration found prescribed optical low vision devices to be useful, and they used the devices consistently over a 3-month period, according to a study published in Optometry and Vision Science.

A prospective cohort study of 199 patients with AMD were examined at the University of Alabama at Birmingham Center for Low Vision Rehabilitation. Participants were enrolled from May 2008 to January 2011, and 181 were prescribed optical low vision devices.

Approximately 48% of participants had received an injection of vascular endothelial growth factor (VEGF) antagonist in at least one eye, but the use of anti-VEGF therapy does not eliminate the need for low vision rehabilitation, according to the study.

“My clinical experience is that patients see a lot better on initial presentation to vision rehabilitation than they did before anti-VEGF and so they have a lot more useful vision for us to work with,” Dawn K. DeCarlo, OD, MS, FAAO, said in an interview with Primary Care Optometry News. “They can go directly to using devices and they tend to need lower power so, all around, they’re more successful.”

Stand magnifiers, handheld magnifiers, near spectacles and hands-free magnifiers were prescribed, with most participants receiving more than one device, depending on the doctor’s recommendation. DeCarlo said the four main factors for deciding which device is most appropriate for a patient are a “combination of the characteristics of the pathology, the patient’s needs and goals, the patient’s acuity and his or her contrast sensitivity.”

The hand and stand magnifiers were used more often than the others. Magnifiers were reported to be moderately to extremely useful by more than 80% of participants at all time points except the 1-month follow-up for hand magnifiers (75%). The most reported usage for the device was leisure reading, followed by managing bills, according to the study.

“Many patients needed a stronger magnifier for certain tasks, but didn’t need it quite as strong for average reading tasks,” DeCarlo said. “Some people just needed the stand magnifier for comfort and long-term reading, but they needed the smaller, more portable handheld magnifier for when they wanted to read menus or price tags in the store.”

In a 2004 study comparing low vision service provision in the United Kingdom for people with AMD (Reeves et al.), 95% of participants reported using at least one low vision aid after 4 months, and 94% reported usage at 12 months. Seventy-two percent used the devices for short-term reading and about a third said they used the aid for more than 5 minutes.

At 1 month in the DeCarlo study, 94% of respondents reported using at least one prescribed device.

“[The study] should really encourage people that these devices are needed and that when they are prescribed appropriately they are used by the patient and they are used a lot,” DeCarlo said.

Future studies will focus on reading speed, print size, reading acuity, scotoma size and location as well as acuity reserve on device use in patients with vision impairment due to AMD, according to the authors. – by Cheryl DiPietro

References:

DeCarlo DK, et al. Use of prescribed optical devices in age-related macular degeneration. Optom Vis Sci. 2012;89(9):1336-1342.Bobier WR, Shaw PJ. A consideration of binocular parameters in the spectacle correction of anisometropic amblyopia: A case report. Optom Vis Dev. 2012;43(2):67-71.
Reeves BC, et al. Enhanced low vision rehabilitation for people with age-related macular degeneration: a randomized controlled trial. Br J Ophthalmol. 2004;88(11):1443-1449.

For more information:

Dawn K. DeCarlo, OD, can be reached at the UAB Center for Low Vision Rehabilitation, CEFH 405, 700 18th Street South, Birmingham, AL 35233; ddecarlo@uab.edu.

Disclosure: DeCarlo has no relevant financial disclosures.