Retinitis pigmentosa is rare heritable diseases which affect photoreceptor and make the patient unable to see normally in dimlight then loss of vision.
2. Retinitis pigmentosa
• Is rare inherited degenerative eye disease that
cause severe vision impairment. In this disease,
the retina is damaged and lead to loss of
photoreceptors (cones and rods) and progressive
vision loss.
• Primary it start to rods as primary degeneration
then follows cones as secondary degeneration.
• Later it affect the central vision , which is needed
for reading, driving, recognizing faces then in
adulthood the patient become blind.
4. Pathophysiology
• Photoreceptors apoptosis
• Retinal degeneration due to failure RPE to
phagocytose the shed rod outer segment discs results
in accumulation of rod outer segment debris
• Defect in the accumulation of cGMP-
phosphosiesterase which leads to accumulation of
toxic level of cGMP
5. Mode of inheritance
• Sporadic: It is called simplex/isolated RP; most
common (50%); only one person in the family
presents with features
• Inherited:
i. AD (25%); best prognosis
ii. AR (25%)
iii. XLR (10%); worst prognosis
6. Clinical symptoms and signs
• Poor vision in dim light (Nyctalopia)
• Progress loss of vision at night (night
blindness)
• Delayed adaptation to bright light
• Flashes of light
• Mild to severe loss of peripheral visual field
• Poor visual acuity (reduced central vision)
• Glares
8. Diagnosis
• History taking; night blindness, familial
history
• Fundal findings; bone spicules, arterioriolar
attenuation and pallor disc+/- macula edema
• Ocular association of RP; OCHTN/POAG,
posterior subcapsular/cortical cataract, myopia,
microphthalmia, keratoconus, PVD, optic disc
atrophy, epiretinal membrane
9. Cont…
• Systemic (syndromic) association
i. Lawrence-Moon-Bandet-Biedl syndrome;
Obesity, MR, polydactyl, polyuria, polydypsia,
hirschsprung disease, renal anomalies
ii. Cockayne syndrome; Cataract, optic atrophy,
dry eyes, squint, nystagmus, corneal opacity
iii. Refsum’s syndrome; hearing loss, loss of smell
and ataxia
iv. Usher’s syndrome; hearing loss
10. Cont…
• Atypical RP
I. Retinitis sine pigmentosa; no bony spicules
II. Cones-rods dystrophy; central/colour vision then
peripheral
III. Retinitis punctata Albesiens; white dots on the
fundus
