By Pippa Wysong
Apps for iPhones, iPads and tablets are creating a brave new world for eyecare professionals and patients alike. Tools available for the devices can provide reminders for patient to go to appointments, give them handy information about their eye condition, or offer basic tests to alert people to changes to their vision. Some apps provide tests that can be used by patients or eyecare professionals alike to assess progression of conditions such as cataracts or macular degeneration.
But many of the available apps have not undergone scientific scrutiny. “There are a rapidly growing number of these apps, but very few have been validated,” cautions Dr. Nadia Northway, an orthoptist and lecturer at Glasgow Caledonian University, Scotland. She presented a poster at the recent joint meeting of the Canadian Ophthalmological Society (COS) and International Orthoptic Congress (IOC) here.
Her own study focused on investigating the effectiveness of the iSight app, an iPad app for measuring visually acuity (VA). For the study, a total of 35 children and 36 adults underwent VA testing using iSight plus conventional testing. The Bailey Lovie chart was used with the adults, and children underwent testing with the Kay picture test. Both groups were retested with iSight and results were compared.
The researchers reported no statistical difference between the iPad measures and conventional eye charts in the adult or the children’s groups (p=0.05). Generally, iSight results showed higher acuity in preschool children than the chart and the test took longer to conduct, in part because the young participants were restless.
Northway noted that some adults complained of blur when the iPad screen was set to 100% brightness, which could be attributed to glare. Researchers reported that correlation to the chart measures and compliance improved when the screen brightness was set to 50 per cent.
Researchers concluded that the iPad app was accurate when compared to results from the charts, and suggest iSight would be a good tool for parents to use to assess their children’s vision.
It could be useful for patients to have this on their personal devices for checking VA, and if they notice a change they can book an appointment with an eyecare professional. “But patients should use information from their eye care professional when undergoing treatment rather than their own measures,” she said.
Another study presented, presented at the COS annual meeting, showed that brightness isn’t the only thing that can affect the usefulness of electronic devices. In fact, researchers from Toronto showed the font is used can effect reading performance of patients who have age-related macular degeneration (AMD).
In a study of 24 patients with bilateral AMD it was found that those with central vision loss can read text written in Courier font better than they can other commonly used fonts. Subjects read text of varying sizes using four versions of the MNRead reading charts.
Patients entered into the study had a mean visual acuity of 0.47 +- 0.19 LogMAR. The charts had text written on them in either Ariel, Times New Roman, Courier, Lucinda sans fonts or Andale Mono. Findings were presented by Luminita Tarita-Nistor, PhD, fellow at the Toronto Western Research Institute.
She explained the differences between the fonts. Courier is a mono-spaced serif font where individual letters each take up the same amount of space. Arial is proportionally spaced in that letters take up varying spaces depending on the size of the letter, and is sans serif. Times New Roman is proportionally spaced, serif font. Lucinda San is mono spaced, and Andale Mono is sans serif, mono spaced.
Generally, fonts that are sans
serif and have variable spacing are commonly recommended by agencies that help the visually impaired. In reading function tests it was found patients could read significantly smaller print with the Courier chart (.58 ± .21 logMAR) and performed the worst with the Arial chart (.69 ± .20 logMAR).
More patients were able to read one or more sentences on the Courier chart than on any of the other charts. However, which font was used had no effect at larger print sizes: with bigger print-sized there was no difference in maximum reading speed with any of the four fonts, she said.
Dr. Tarita-Nistor noted that the Canadian National Institute for the Blind (CNIB) recommends Arial, and concluded that recommendations should be revised.
A variety of apps for vision are available for both patients and healthcare professionals. A recent editorial in the Nature journal Eye (2012, 26, 343–354) lists over 40 apps that are available. Many provide tests for VA, information about disease conditions or offer reminders about going to see eye care professionals. Some also have Amsler grids for AMD, tests for colour blindness, tests for astigmatism, duochrome testing, and even far field vision testing. Some include apps for locating local opticians, have eye quizzes, advice and facts about the eye and vision. Some are designed for patients, others are designed for use by eyecare professionals, the editorial says.
The authors note that such apps are likely to increase in number as well as in the types of potential uses, especially for professionals. For
instance, there has already been work done adding technologies so phones and tablets can aid in diagnosis and the monitoring of patients in remote areas for telemedicine purposes.
For instance, MobiUS developed a smartphone ultrasound imaging device. It uses a hand-held wand and the smartphone works as a portable imaging system. It has FDA approval in the US. The authors state “this could be suitable for ocular ultrasound examination”.
Another item on the market is a slit lamp that can work with an iPhone with specially designed adaptors. Also, iPhones have been used in teleophthalmology relating to retinopathy of prematurity in India, but these have required large imaging devices.
However, in future, “it is likely that an attachable fundus camera will fit directly on to a smartphone with wide field images created by existing photo-stitching packages and making it a truly portable fundus camera,” the authors said.
The editorial in Eye concluded that “Rapidly advancing technology has literally put knowledge in the palm of our hands. The possibilities for investigations, teaching, information sharing, research, collaboration, and ultimately improved patient care are endless.”
Dr. Northway added “It is to be expected that people will use these apps, however visual acuity is only one aspect of visual processing. Success (on an iPhone test) does not mean everything is OK. Vision is complicated, but the fact that parents can assess their own child using a validated app could be advantageous. Patients should always remember to see a professional if concerned.”