Retinitis pigmentosa, or pigmentary dystrophy of the retina, covers a group of inherited, progressive retinal conditions characterised by degeneration of the photoreceptor cells and advancing loss of sight. More and more photoreceptors are lost and patients perceive a narrowing of the visual field, which ultimately leads to practical blindness and disability. The gradually worsening symptoms may include
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tunnel vision, as a result of a restricted visual field and loss of peripheral vision
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poor or blurred vision at night while driving, or night blindness
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shimmering spots and/or flashes of light
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very slow adaptation to dim light
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sensitivity to light
Loss of the visual field — a consequence of retinitis pigmentosa — leads to a number of deficits, including the ability to read. Compensatory strategies become necessary, such as moving the hands to centre the characters being read within the visual field, or moving the head to extend the reading distance. A shrinking visual field also causes a change in contrast sensitivity — the ability to distinguish between shades of grey — which affects everyday functioning, lifestyle and social development. There is no doubt that advanced sight loss has a negative effect on patients' quality of life. It can also be diagnosed during a routine eye examination, where abnormal dark pigment deposits are present in the retina alongside worsening difficulties related to night blindness and visual field defects.