Prof. Dr.M Hafiz Rafique
‘A thing of beauty is a joy for ever’. This is one of the famous quotations of an English poet John Keats (1795-1821). However, the beauty of a beautiful thing can only be enjoyed if one has eyes with correct vision. Unfortunately the blind people are deprived of this blessing and cannot enjoy seeing beautiful things of this marvelous and ever-changing world.
We see things around us with our eye(s). When light rays, from any illuminated object, fall on our eye, the cornea of the eye bends them and let them pass through the pupil. The iris shrinks or expands to control the intensity of the light that are enters into the eye. The functioning of the iris is just like the shutter of a camera. After passing through the iris, the light rays pass through the natural crystalline lens and are focused on the retina of the eye to make an inverted image of the object from where the light rays are coming. The retina is just like the film in a camera. The retina processes all the light rays into light impulses/electronic signals with the help of millions of tiny nerve endings. Ultimately the light impulses are transferred, through over a million nerve fibers, to optic nerves and finally to the brain which perceives the image of the object and we see the object in front of us.
Although many countries have made a lot of development in surgical techniques, cataracts (47.9%) is the main cause of visual impairment in the world. Other causes of blindness and visual impairment include onchocerciasis (0.8%), trachoma (3.6%), childhood blindness (3.9%), diabetic retinopathy (4.8%), corneal opacities (5.1%), age-related macular degeneration (8.7%) and glaucoma (12.3%). According to one of the reports of World Health Organization (WHO), the avoidable blindness population in different regions of the world comprises: European 9.6%, the USA 9.6%, Eastern Mediterranean 10%, African 16.6%, Western Pacific 26% and South East Asian 28%.
A bionic eye is a man-made eye created by California Company that can restore vision of blind people. Basically, it is a combination of an external eyeglass-mounted camera and a sophisticated retinal implant. The camera consists of a microchip which processes the image of the object and wirelessly transmits data to the retinal implant. The retinal implant sends information to the optic nerves which distinguish between light, shape and movement and finally the brain perceives the image of the object.
A bionic eye costs about $145,000 and some 80 visually-impaired people have benefitted from this device. It still has some technological issues and the scientists are making effort to improve its efficiency and workability.
(The writer is Punjab University Physics Department Chairman and Member Syndicate on Associate Professor’s seat. He can be reached at: firstname.lastname@example.org)