vascular and hereditary retinal disease

VASCULAR AND HEREDITARY RETINAL

DISEASE

Dr Russell J Watkins

Hypertension Affects 15-20% of the population Asymptomatic (if essential) Morbidity arises from complications

Ischaemic heart disease Cerebrovascular disease Renal failure

Appropriate treatment prevents complications

Hypertension Definitions (WHO & ISH)

Normotension systolic <140mmhgdiastolic <90mmhg

Borderline systolic >140 to <160diastolic >90 to <95

Hypertension systolic >160diastolic >95

Hypertension Essential hypertension

95% of hypertension is idiopathic Secondary hypertension

5% is due to other medical conditions• Mainly renal disease• Other causes very rare

Hypertension Both essential & secondary hypertension can be

subclassified as Benign Malignant or accelerated

Hypertension The spectrum of hypertensive eye disease

[Arteriosclerotic retinopathy] Hypertensive retinopathy CRVO/BRVO CRAO/BRAO AION Cranial neuropathies

Hypertensive Retinopathy Grading

Grade 1: arteriolar silver wiring Grade 2: grade 1 changes + AV nipping Grade 3: grade 2 changes + haemorrhage,

exudate & cotton wool spots Grade 4: grade 3 changes + disc swelling

Macular star Occurs if exudates collect in Henle’s layer

Arteriosclerotic Retinopathy NOTE not ATHEROsclerosis

Usually associated with hypertension Accelerated by DM

Arteriosclerotic Retinopathy Signs

AV nipping (Salus’ sign) Dilated vein distal to AV crossing (Bonnet’s sign) Tapering of vein either side of AV crossing (Gunn’s

sign) Right angle deflection of vein Arteriolar “silver wiring” Ischaemic choroidal infarcts (Elschnig bodies) Retinal arterial macroaneurysm Ischaemic optic neuropathy

Retinal Macroaneurysm Occurs in

Elderly hypertensive patients Arteriosclerotic patients

Single or multiple Usually at posterior pole

Retinal Macroaneurysm Outcomes:

May occlude spontaneously May bleed - trilayer haemorrhage May leak → circinate exudate ±macular

oedema Management

Refer as priority Either managed conservatively or undergo

focal/grid photocoagulation

Retinal Vein Occlusion Causes

Pressure on the vein• AV nipping, ↑IOP

Vessel wall disease• DM, periphlebitis

Hyperviscosity• Hyperlipdaemia, polycythaemia, myeloma,

leukaemia

Retinal Vein Occlusion Clinical signs

Dilated veins Flame shaped haemorrhages Retinal oedema CWS Venous sheathing (occasionally arterial) Exudates

Retinal Vein Occlusion Complications

Macular oedema NVD & NVE

• Tractional RD• Rubeosis (100-day glaucoma)

Optometric management Referral as priority for investigation of

underlying cause Photocoagulation if marked ischaemia/NV

Retinal Artery Occlusion Causes

External pressure• CAG, RD surgery

Vessel wall disease• Atheroma, arteritis (GCA, PAN, SLE)

Embolisation• Carotid, cardiac wall or valve

Retinal Artery Occlusion Types of embolus

Cholesterol (Hollenhorst plaques) Fibrinoplatelet (amaurosis fugax) Calcific (usually permanent occlusion)

Retinal Artery Occlusion Clinical features

Sudden painless loss of vision Field defect if BRAO APD White, oedematous retina with reflex from

choroidal vessels visible at fovea (cherry red spot)

~20% develop rubeosis Optic atrophy with no other features

Retinal Artery Occlusion Optometric management

Refer as emergency• May be GCA, though this is less likely than

embolus• Recovery unlikely (but possible)

Possible measures• Ocular massage in supine position• IV acetazolamide• AC paracentesis• CO2 rebreathing

Retinopathy of Prematurity A cicatrising or proliferative retinopathy affecting

premature babies ? Exposure to high levels of oxygen In the UK, all neonates <32/40 gestation are

screened Severe ROPs are treated with photocoagulation

or cryotherapy Classification depends on degree of peripheral

retinal changes, fibrovascular proliferation & vitreoretinal traction

The most severe ROP causes total RD & 2° ACG

Hereditary retinal disease…

Retinitis Pigmentosa Group of progressive bilateral disorders of retinal

photoreceptor/RPE complex Triad of

Night blindness Visual field defect Typical fundal appearance

RP may be familial RP may be associated with other defects & may

be the result of a syndrome

Retinitis Pigmentosa Symptoms

Night blindness Visual difficulties because of field loss Photophobia & glare

Patients with RP may have Myopia PSCLO Keratoconus Optic disc drusen Glaucoma CMO

Retinitis Pigmentosa Early signs

↓dark adaptation Annular scotoma Equatorial patchy RPE atrophy & hypertrophy Attenuated retinal vessels

Retinitis Pigmentosa Late signs

Tubular fields (2-3°) Bone corpuscle pigmentation Choroidal atrophy Retinal venous sheathing Drusen Waxy optic atrophy

Retinitis Pigmentosa Inheritance (varies with geographical location)

AR 51% AD 26% XLR 23%

Prognosis 25% maintain adequate reading vision LVAs usually required

Retinitis Pigmentosa Atypical variations

Sine pigmento Macular type (preceding macular changes) Pericentric (possible rod-cone dystrophy) Sectoral (symmetrical, bilateral, commonly

inferonasal) Fundus albipunctatus

Choroidal Degenerations

Central areolar sclerosis (AD/AR) Onset 20-40yrs Bilateral central

atrophy Progressive visual loss Normal

electrophysiology

Choroidal Degenerations Gyrate atrophy (AR)

Treatable biochemical abnormality

Onset 10-30yrs Night blindness &

tunnel vision Progressive, patchy,

equatorial atrophy Myopia & cataract Abnormal

electrophysiology

Choroidal Degenerations Choroideraemia (XLR)

Onset 5-15yrs Progressive night

blindness Eventual total

blindness Progressive granular

pigmentary changes Late - total choroidal

atrophy Carrier state exists

Albinism Failure of melanocyte/melanosomes Variable deficiency of melanin Enzyme defects are

Tyrosinase positive Tyrosinase negative

Types of albinism Generalised (oculocutaneous) - AR Ocular - XLR

Albinism Oculocutaneous albinism

T-pos• Mild, improves with age• Iris transillumination• Nystagmus• Poor vision• Refractive errors

Albinism Oculocutaneous albinism

T-neg• Severe disease• Photophobia• Poor vision & large refractive errors• Nystagmus• Iris transillumination• No fundal pigmentation or foveal reflex• Abnormal chiasmal decussation →

abnormal architecture of LGN

Albinism Ocular albinism (XLR)

Confined to eyes Giant melanosomes in RPE Carriers have iris transillumination & granular

RPE