THANKS to the persistence of a poet frustrated by her loss of sight, researchers in Boston have shown that a device for diagnosing eye disease could allow people with limited vision to access the Internet, read simple texts, or see their family鈥檚 faces for the first time. Unfortunately, the cost of the system is still an obstacle.
Scanning laser ophthalmoscopes were originally designed to allow doctors to study a patient鈥檚 retina by shining a laser onto the back of the eye (Technology, 11 June 1987). The laser light illuminates the retina, which can be observed by a camera. Instead of using a wide beam to illuminate all the retina at once, the SLO uses a single point of laser light which 鈥渟cans鈥� an area of retina in a series of rapid passes 鈥� in the same way that the electron beam of a TV tube scans across the screen. This design allows an image to be shone onto the retina.
Elizabeth Goldring is a poet and the director of exhibits at the Massachusetts Institute of Technology鈥檚 Center for Advanced Visual Studies. She was first introduced to an SLO by her ophthalmologist, Lloyd Aiello. Goldring, who had haemorrhages in the front of her eyes caused by diabetes, was blind at the time although surgeons have since restored some of her vision.
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As Goldring peered into the SLO, Aiello used the laser to project a simple image of a turtle directly onto the retina of one eye, past the haemorrhages, while he observed an enlarged image of the retina on a monitor. The idea was to determine whether she had any healthy retina left. Fortunately she did and was able to see the turtle.
Goldring then asked Aiello to write the word 鈥渟un鈥� and transmit that through the SLO. 鈥淚 could see it,鈥� she says. 鈥淭hat was the first time in several months that I鈥檇 seen a word, and for a poet that鈥檚 an incredible feeling. Keeping my visual sense active is extremely important to me.鈥�
Goldring then contacted the inventor of the SLO, Robert Webb of the Schepens Eye Research Institute in Boston. Together, they have continued to experiment with the SLO, most recently over the Internet.
To prove its potential use over a network, the SLO was hooked up to a Macintosh computer which could transmit text or pictures to the SLO. It also sent an image of Goldring鈥檚 retina to doctors in another office to demonstrate remote diagnosis.
Webb used a video camera to transmit an image of his face to the SLO for projection onto Goldring鈥檚 retina. Although her vision in one eye is now sufficient to see faces as very fuzzy 鈥渕oons鈥�, this was the first time she had seen Webb鈥檚 face clearly.
When she first began reading through the SLO, Goldring found it exhausting after just a few minutes. She can now use it for up to two hours each day. Goldring has also created a 鈥渧isual language鈥�, consisting of short words that incorporate graphics and symbols that illustrate the meanings of words and make them easier to see. She is using this language to create short texts, such as poetry, that can be enjoyed by people with visual problems. Reading dense text is still beyond her.
鈥淲e never expected it [the SLO] to be used that way,鈥� says Webb. 鈥淭here are millions of people in the world with diabetic retinopathy, macular degeneration and other eye disorders who have some functioning retina, yet no useful vision. If I were designing a reading machine for them, it would be very much like the SLO, with a red laser and a scanning device.鈥�
But SLOs are bulky and expensive 鈥� the machine used by Goldring cost $100 000 鈥� and Webb is cautious about the prospect of adapting SLOs as reading machines. 鈥淭he economics are not very encouraging,鈥� he says.
