Retinitis Pigmentosa

Question 1

DEFINITION

Answer 1

• Inherited diseases

- Progressive deterioration of photoreceptor and retinal pigment epithelial structure and function.

Question 2

EPIDEMIOLOGY

Answer 2

Single gene retinal dystrophies with simple Mendelian inheritance and any type of inheritance pattern may occur.

Question 3

CLINICAL FINDINGS

Answer 3

SYMPTOMS

1. Bilateral and relatively symmetrical.
2. The age of onset and speed of progression varies between and within affected families.
3. Night blindness (first symptom)
4. Clumsiness due to the gradual reduction of visual field.
5. Initially visual acuity is unaffected, but it declines later.

SIGNS
FUNDOSCOPY
1. Irregular retinal pigment epithelial clumping is first noticed in the midperiphery. bone spicule appearance.
2. Retinal pigment epithelial atrophy produces depigmentation between the areas of pigment clumping.
3. Pigment changes spread centrally and peripherally. The macular area is spared until very late in the course of the disease.
4. Retinal arterioles are narrowed due to retinal atrophy.
5. Eventually, the disc becomes pale as a result of the loss of nerve fibres

VISUAL FIELDS
Ring scotoma that gradually enlarges peripherally and centrally.

Question 4

SPECIAL INVESTIGATIONS

Answer 4

Electroretinogram (ERG) is diagnostic, and is especially useful in the earlier stages of the disease

Question 5

MANAGEMENT

Answer 5

1. Long term oral vitamin A
2. Low vision aids such as magnifying glasses, telescopes and illumination systems to help visually handicapped patients make the most of their remaining vision.
3. Refered to Retinitis Pigmentosa Association for information, help and
   support.
4. Genetic counselling for family planning.
5. Education: career choice.
6. Visually handicapped children referred to special schools.
7. Gene therapy, stem cell therapy and retinal protein delivery systems