for ophthalmology residents

1. RETINITIS PIGMENTOSA
Othman Al-Abbadi, M.D

2. Retinitis Pigmentosa
• Inherited diffuse retinal degenerative diseases
• Most common hereditary fundus dystrophy
(1/5.000)
• Initially predominantly affecting the rod
photoreceptors, with later degeneration of cones
• May occur as
–AD
–AR
–XLR
–Sporadic

3. Modes of inheritence
• XLR is the least common but most severe form,
and may result in complete blindness by the
third or fourth decades
• AR disease can also be severe
• Sporadic cases may have a more favourable
prognosis, with retention of central vision until
the sixth decade or later
• AD disease generally has the best prognosis

4. Symptoms
• Nyctalopia and dark adaptation difficulties are
frequently presenting symptoms
• Mid-peripheral then far-peripheral field loss
• reduced central vision (late)
• Cataract
• Photopsia

5. Signs
• Triad of
• bone-spicule retinal pigmentation
• arteriolar attenuation
• ‘waxy’ disc pallor

6. Progression
• Bilateral mid-peripheral intraretinal perivascular
‘bone-spicule’ pigmentary changes with
arteriolar narrowing
• Then a gradual increase in density of the
pigment
• Anterior and posterior spread
• Peripheral pigmentation may become severe,
with marked arteriolar narrowing and disc pallor

10. • The macula may show
• Atrophy
• epiretinal membrane formation
• cystoid macular oedema (CMO)
• Myopia is common.
• Optic disc drusen occur more frequently

11. Complications
• PSCC
• OAG
• Keratoconus
• PVD
• Intermediate uveitis
• Exudative RD

12. Investigations
• ERG
• EOG
• Perimetry
• OCT
• Genetic analysis

13. ERG
• ElectroRetinoGram
• Components
• A wave photoreceptors
• B wave muller cells + bipolar cells
• C wave RPE

14. ERG
• Sensitive diagnostic test
• Early  reduced scotopic rod and
combined responses
• With progression  photopic responses
also reduce

16. EOG
• Measurement of standing potential between the
cornea and the retina
measurement of function of the RPE and
photoreceptors
• Abnormal in RP
• However, ERG is considered a more sensitive
test for detection of photoreceptor function and
consequently EOG is not routinely done

17. Visual field
• Characteristically shows a ring scotoma in the
mid-periphery of the visual field
• Start as a group of isolated scotomas around 20
degrees from fixation, and gradually coalesce to
form a partial followed by a complete ring
• Useful in monitoring the progression of disease
and document the status of legal blindness

18. OCT
• to detect
• CMO
• Epiretinal membrane
• vitreomaular traction

19. Treatment
• Many treatments have been explored without
proven benefit
• These include various vitamins and minerals,
vasodilators, tissue therapy with placental
extract, cortisone, cervical sympathectomy,
injections of a hydrolysate of yeast RNA,
ultrasound, transfer factor, dimethyl sulfoxide,
ozone, muscle transplants, and subretinal
injections of fetal retinal cells

20. Atypical retinitis pigmentosa
• Syndromic
• Usher syndrome
• Kearns–Sayre syndrome
• Bassen–Kornzweig
syndrome
• Refsum disease
• Bardet–Biedl syndrome
• Non-syndromic
• Retinitis pigmentosa sine
pigmento
• Retinitis punctata
albescens
• Sector retinitis pigmentosa
• Leber congenital
amaurosis
• Pigmented paravenous
chorioretinal atrophy

21. Usher syndrome
• About 15% to 20% of affected individuals with retinitis
pigmentosa have associated hearing loss
• There are three major types;
• Type I (75%) which features profound congenital
sensorineural deafness and severe RP with an
extinguished ERG in the first decade plus unintelligible
speech & vestibular ataxia
• Type III (2%), with progressive hearing loss, vestibular
dysfunction and relatively late-onset pigmentary
retinopathy

22. Kearns–Sayre syndrome
• Part of chronic progressive external
ophthalmoplegia
• Mitochondrial inheritance
• Abnormalities include
• Ptosis
• diffuse disturbance of the RPE
• ERGs that are usually reduced in amplitude
• respiratory distress
• heart block which may require a pacemaker

23. Bassen–Kornzweig syndrome
• Abetalipoproteinaemia
• Malabsorption of fat and fat-soluble vitamin
• Develops FTT in infancy
• The fundus exhibits scattered white dots
followed by RP-like changes developing towards
the end of the first decade; there may also be
ptosis, ophthalmoplegia, strabismus and
nystagmus

24. Refsum disease
• The patient accumulates exogenous phytanic acid
• Findings include a peripheral neuropathy, ataxia, an increase
in CSF protein with a normal cell count, and retinitis
pigmentosa
• All have elevated serum phytanic acid
• A defect exists in the conversion of phytanic acid to alpha-
hydroxy phytanic acid which results in its accumulation
• Treatment consists of restricting not only animal fats and
milk products (i.e., foods that contain phytanic acid) but also
green leafy vegetables containing phytol

25. Bardet–Biedl syndrome
• Includes RP, mental retardation,
polydactylism, apple-shaped obesity, and
hypogonadism
• Almost 80% have severe changes by the
age of 20 years

26. Retinitis pigmentosa sine
pigmento
• Sine pimento = Without pigment
• Absence or paucity of pigment accumulation
• May subsequently appear with time
• Functional manifestations are similar to typical
RP

28. Retinitis punctata albescens
• Albescens = whitish
• Scattered whitish-yellow spots, most
numerous at the equator, usually sparing
the macula, and associated with arteriolar
attenuation
• Nyctalopia and progressive field loss occur

30. Sector retinitis pigmentosa
• Sectoral RP
• AD
• Characterized by involvement of inferior
quadrants only
• Progression is slow (many cases are
apparently stationary)
• Unilateral RP can also occur

32. Leber congenital amaurosis
• Severe rod-cone dystrophy
• The commonest genetically defined cause of
visual impairment in children
• ERG is usually non-recordable even in early cases
• Systemic associations include
• mental handicap, deafness, epilepsy, central
nervous system and renal anomalies, skeletal
malformations and endocrine dysfunction

33. • Presentation
• Blindness at birth or early infancy
• associated with roving eye movements or
nystagmus
• Photoaversion
• Cataract
• Hypermetropia
• Nestagmus

34. • Signs are variable but may include:
• Absent or diminished pupillary light reflex
• The fundi may be normal in early life apart from mild
arteriolar narrowing
• Initially mild peripheral pigmentary retinopathy, salt
and pepper changes, and less frequently yellow flecks
• Severe macular pigmentation
• Pigmentary retinopathy, optic atrophy and severe
arteriolar narrowing in later childhood
• Oculodigital syndrome: constant rubbing of the eyes
may cause orbital fat atrophy with enophthalmos, and
subsequent keratoconus or keratoglobus

37. Pigmented paravenous
chorioretinal atrophy
• Pigmented paravenous chorioretinal atrophy
• Usually asymptomatic and non-progressive
• ERG is normal
• Paravenous bone-spicule pigmentation together
with sharply outlined zones of chorioretinal atrophy
that follow the course of the major retinal veins
• Changes may also encircle the optic disc
• The optic disc and vascular calibre are usually
normal