For low vision specialists and those who consult them
USA visit report 2/3: Brainport and the OCT-SLO
During my stay in the US, I spent a day visiting Drs Aries Arditi and Bill Sieple at Lighthouse International in New York. Lighthouse is a very well established centre for low vision rehab, advocacy and research (and also includes dance and music studios for the visually impaired, a pre-school, a reading centre, a braille unit, and many other services). Whilst there I saw two very interesting devices.
First, I had a go with a Brainport unit. This system translates visual information (captured through a camera mounted onto spectacles) into electrical pulses on a 20×20 grid. This grid is placed into your mouth, so you can feel the shape of the scene you’re looking at through impulses on your tongue. I must admit that it just made me dribble like a village idiot, but apparently that reflex subsides after time, and people can differentiate large letters with this system (after training). I can see that this may be a useful adjunct to another mobility aid for people with no vision (it could, for example, help find a high contrast doorframe in a plain corridor).
The second instrument I saw was the OTI/OPKO OCT-SLO. This combines an Optical Coherence Tomography (OCT) device with a Scanning Laser Ophthalmoscope (SLO). OCT creates cross-sectional images of the retina (it can detect subretinal fluid for example, which is very important in differentiating wet from dry macular degeneration). It also measures retinal thickness. The SLO captures a high quality greyscale retinal image even without pupil dilation. What makes this system different is it also includes a OLED display for the subject to observe. This means it can be used for retinal-specific microperimetry: it can test the function of specific parts of the retina. It even includes a module to check visual acuity at different retinal areas (although it can’t measure acuity better than 20/70 (6/21) due to pixel resolution).
It’s a nice instrument and would be good to have in a clinical environment where you are interested in structure and function. Add-on modules enable you to do anterior chamber and optic disc imaging as well. The image quality and display quality are good: far superior to the Nidek MP-1 microperimeter, for example. It appeals to me less as a research instrument as the software is very sealed and you can’t make any changes to it yourself (for example, you can’t switch the VGA input as you can on the MP-1). Also, the visible raster of the SLO imaging system is quite distracting when you sit as a patient.
Anyway, it was an interesting visit to the Lighthouse. Thanks to Aries and Bill for hosting my visit!