SOME CAUSES OF VISUAL IMPAIRMENT

Retinitis Pigmentosa
Reproduced courtesy of The Low Vision Centers of Indiana

Retinitis Pigmentosa Low Vision Care

Low Vision rehabilitation of patients with retinitis pigmentosa center around several issues: light and glare problems, visual field loss, task light needs,decreased central vision in later stages and night blindness.

		Light & Glare: Whiteout Glare in Bright Sun

Patients with RP and related diseases live in a world where light and glare constantly interfere.  For many RP patients, walking outside into the sun   may result in being overwhelmed by brightness to the point of temporary disability. The same might happen to us he we attend a daytime movie then walk out into bright sun. For the RP patient, this may happen continually. Light and glare symptoms will vary depending on  the degree of damage Amber filters of varying density may help these patients. Very dark filters such as the dark plum may be required by some. Others may find a dark amber adequate. The patient's we have followed over several decades generally require more filter initially as the condition begins but less density in their filters as the decease becomes more advanced. Hats and visors are often helpful and wraparound sun wear with side shield effects are helpful.

		Loss of Visual Field: Tunnel Vision

Visual field  awareness systems may be employed to aid loss of peripheral vision. Our experience has been that reverse telescopes or amorphic lens work for many patient but success is more likely  when the patient's visual field are constricted under ten degrees. To use a reverse telescope the patient must have good visual acuity. We recommend 20/40 or better but never less than 20/80 since the reverse telescope will minify objects and thus make the acuity lower In cases of  decreased visual acuity and visual field loss, prisms may still be employed. These include the InWave Retinitis pigmentosa lenses, the Gottlieb Visual Field Awareness System and Press-on Visual Field Prisms. Prisms can be successfully employed earlier than reverse telescopes.

		Nyctalopia: Night Blindness

Night blindness may be dealt with by increasing light levels inside and out at home. Supplemental task lighting is usually helpful to RP patients.  In some cases where night travel is frequent, night scopes are employed. These scopes are similar to those used by the military in Operation Desert Storm.

		Decreased central vision combined with loss of peripheral vision

In the later stages of RP the central vision may become effected from damage to the macula. These patient have less peripheral field to use to overcome the loss. The white on black high contrast letters capable on CCTV magnification system works well for these patients. Other low vision eye wear and magnifiers may be employed successfully on a case by case basis. If a patient is unable to be helped by conventional low vision systems, electronic reading machines, talking books and reading radio may also be helpful.