Single bioptic telescope for low vision driving may not obscure road view of second eye

Boston, MA — A study by scientists at Schepens Eye Research Institute shows that a bioptic telescope on one lens of a pair of glasses used to magnify traffic signs and lights may not prevent the wider view of the road with the second eye. The study results, which will be published in the May 2011 Archives of Ophthalmology, are the first evidence that–under more realistic viewing conditions than in earlier studies–the second eye can detect objects in the area obscured by the magnification effect of the telescope (called the ring scotoma).


“These study results are significant because they should ease official and public concerns about the safety of bioptic telescope use for driving with visual impairments,” says Dr. Eli Peli, the principal investigator of the study, who is a low vision expert, a senior Schepens scientist, and a professor of Ophthalmology at Harvard Medical School.

In previous studies, participants wearing the bioptic telescope were asked to view a blank (plain) background and focus on a simple fixation point — a cross — while detecting random visual targets presented to them, a task that requires little attention and concentration.

“Our current study required subjects to view more complex, textured backgrounds and focus on and read letters, which are more akin to visual situations encountered in real life and on the road,” says Peli.

Bioptics, improved something greater than 100 years back, are minor telescopes that are joined above the focal point of one spectacle lens. A slight descending tilt of the head and upward change of the eyes can carry a far off street mark or activity light into view for individuals with vision impedances. When looking through the telescope, a without vision dominion (scotoma) is made owed to the amplification of the telescope. The destitute of vision range is in the shape of a ring surrounding what is perceived through the telescope (consequently the name “ring scotoma”). Case in point, an individual review an activity light with the telescope can see the light, but should not see the surrounding crossing point, with the same eye. Admitting that bioptics were presented as driving supports 50 years in the past and are sanction for heading in 39 states, safeguard has remained a concern, specifically the impact of the ring scotoma on identification of activity risks. In some states this concern bring about limiting the telescope to one eye just, leaving the different to screen the territory of the ring scotoma at the same time as telescope utilize.


In the Archives of Ophthalmology ponder, Amy Doherty, the first creator, and the exploration crew, led an arrangement of tests assessing the fitness of the second (partner) eye to recognize targets in the region of the ring scotoma on both basic and complex underpinnings, with and without the bioptic telescope on one lens.

They started by fitting 14 subjects with bioptic glasses and utilized a novel presentation framework that permitted them to display screen stimuli to each and every eye in parts while both eyes were looking at the screen. The group then “mapped” or resolved the measurements and position of the unseeing region (ring scotoma) in each subject's telescopic eye by exhibiting superficial stimuli just to that eye.


Following, each and every subject underwent four review conditions while wearing the telescope in front of one eye, and the same four conditions without the telescope. In all cases, both eyes were open, while an image stimulus or target (a humble checkerboard square), displayed to the second eye just, showed up erratically in better parts of the ring scotoma range. The subjects pressed a catch whenever they saw the target.

The four conditions were: latently survey a cross on a faded base level, latently review a cross on a more complex textured grounding, actively perusing letters on a faded base level, and actively perusing letters on the textured underpinning level. The textured underlying level perceived amplified in the telescopic eye bring about a contention (rivalry) impact betwixt the visualizations from the a few eyes that might outcome in the cerebrum overlooking (stifling) the visualization from the second eye. Any suppression of the second eye when looking through a bioptic telescope would be able to reasonably consequence in an activity risk not being observed.


In all cases no critical distinction was found among what the second eye saw when the first eye was utilizing the telescope and when it wasn’t utilizing the telescope. With the bioptics, the second eye was equipped to locate the target 86 percent of the time, while without the bioptics, it recognized the target 87 percent of the time. As looked for, additional targets were distinguished on a faded base level than on a textured underlying level and while centered on an effortless cross than while perusing letters.

“The proposed consequences propose that the bioptic driver would not be able to be heedless to activity when looking through the telescope, in light of the fact that the second eye can catch targets in the range clouded by the telescope,” expresss Doherty.

While the academic work outcomes are empowering, Peli and Doherty concur that it is still key to test the utilization of bioptics in significantly more sensible factors.

“Our following testing conditions will be with motion picture fragments that nearly copy the screen scene and regard needed in the midst of exact driving scenarios,” declares Doherty, who unites that as time marches onward, the exploration group moreover would like to garner information from driving re-enactment devices and even exact on-the-way screening.

Drs Alex Bowers and Gang Luo, additionally in The Mobility Enhancement and Rehabilitation Center at Schepens Eye Research Institute, committed to the inquiry.

Schepens Eye Research Institute is a partner of Harvard Medial School and the most imposing free eye exploration organization in the country.