Projects

The Kinematics of Braille Reading

[Under construction]

When blind persons read braille, a system of raised dots for tactile reading and writing, how is the information processed? How do a few indentations on the fingerpads translate to linguistic information, and how does the text, in turn, influence the motions of the hands reading it? Our work on braille addresses these processes on several levels.

 

The Macular Mapping Test

The Macular Mapping Test (MMT) is a tool for the assessment of the topography of vision. It is a quick and low-cost alternative to conventional perimetry in practical low vision care.

While standard perimetry uses a detection task, the MMT measures the recognition of single letters in the center and near periphery (+/- 10 deg) of the visual field. Their sizes increase according to eccentricity and can be shown at different contrast levels. Each letter is displayed only for a brief moment (250 ms). One test run of 36 trials takes only about 3 minutes.

We have tested patients with early age…

The Macular Search Test

We introduced a novel approach to topographic function assessment in visual impairment that requires neither fixation nor reading.

The test measures the time it takes for patients to find and identify 32 targets on a screen. The task discourages steady fixation and the subjects can make eye movements as needed to solve the task. Target size is always double the size threshold, and no manual action is required.

We have used this test on many low vision patients with varying diagnoses. Measurements yielded a wide variety of performance levels, with a factor of 14-16 between best and worst…

The Role of Selective Visual Attention in Amblyopic Suppression

Individuals with strabismus are confronted with double vision, their brain has to choose to attend to one image and ignore or suppress the other. It has been commonly suggested that a constant suppression on the non-preferred eye in strabismus is responsible for the development of amblyopia. In the current project, we study the role of top-influences of attention in amblyopic suppression and test the hypothesis that visual suppression in amblyopia may be a form of long-term attentional “neglect”.

The Smith-Kettlewell Technical File

 

The Smith-Kettlewell Technical File, edited by William Gerrey (WA6NPC), was a publication by and for blind and visually-impaired electronics professionals and enthusiasts. It was published by the Smith-Kettlewell Eye Research Institute from Fall 1980, through Spring 1998 and was at various times available in Braille, large print, audio cassette, and 5-1/4" floppy diskette.

Although The Smith-Kettlewell Technical File is no longer in active publication, we offer this online archive as a resource of both current and historical value.

While many of the articles about devices and techniques remain…

Tracking a target in depth with central field loss

Bilateral field loss due to maculopathy creates a scotoma that extends in depth — a volume scotoma. Morevoer the size of the scotoma depends on whether observers turn their eyes to track a target as it comes closer. This project investigates how the volume scotoma affects the ability to track oncoming targets in these individuals, and in controls with a simulated volume scotoma.