Sickling hemoglobinopathies are genetic blood disorders caused by abnormal hemoglobins that cause red blood cells to take on an anomalous sickle shape and become rigid under conditions of low oxygen and acidity. These misshapen red blood cells can get stuck in and block small blood vessels. Specific disorders include sickle cell anemia, sickle cell trait, sickle cell C disease, and sickle cell thalassemia. Ocular complications range from mild and asymptomatic to proliferative retinopathy, which involves the growth of abnormal new blood vessels on the retina and can lead to vision loss from bleeding or retinal detachment. Non-proliferative retinopathy presents as venous tortuosity, silver wiring of

1. By-
Harsh Jain
B.V.P –B.Optometry

2. Sickling Haemo-globino-pathies
 Sickling Haemo-globino-pathies are caused by
one, or a combination of abnormal
haemoglobins which cause the red blood cell
to adopt an anomalous shape under conditions
of Hypoxia and acidosis.
 Because these deformed RBC are more rigid
than healthy cells,they may become impacted
in and obstruct small blood vessels.

3. Sickling Haemo-globino-pathies
• The sickling disorders in which the mutant
haemoglobins S & C are inherited as alleles of
normal haemoglobins A have important ocular
manifestations.
• These abnormal haemoglobins may occur in
combination with normal haemoglobins A or in
association with each other as indicated
below:-

4. Sickel Cell Disease {Sickel cell anaemia}
• It affects 0.4% of black americans and is caused
by a point mutation on the beta-Globins gene.
• The disease is characterized by severe chronic
haemolytic anaemia and periodic,potentially fatal
crises due to Vaso-occlusive disease involving
most organs resulting {Liver necrosis, Painful
crises,abdomial pain,acute chest syndrome and
CNS symptoms.
• Ocular complication are usually mild and
asymptomatic.

5. AS-Sickel Cell Trait
• It is present in 10% of black americans.
• It is the mildest form and usually requires
severe hypoxia or other abnormal
conditions to produce sickling.

6. SC-Sickel Cell C disease
• It is present in 0.2% of black americans.
• It is characterized by haemolytic
anaemia and infarctive crises that are
less sever than in SS disease but may
be associated with severe retinopathy.

7. SThal –Sickel Cell Thalassaemia
• It is characterized by mild anaemia but
may be associated with severe
retinopathy.

8. Note
• Retinopathy is more severe in SC and
Sthal

9. Differential Diagnosis

10. Proliferative Retinopathy
Stage:- 1
• Peripheral arterial occlusion and
ischemia.
Stage:- 2
• Peripheral arterio-venous anastomoses
of dilated pre-existent capillary
channels.

12. A.Pheripheral Aterio-ventrical anastomosis
B. Sea-Fan Neo-vascularization

13. Stage:- 3
• Sprouting of new vessels from anastomoses
which have Sea-Fans configuration and are
usually feb by a single ateriole and drained
by a single vein.
• Sea-Fans involute spontaneously as a result
of auto-infarction and appear as greyish fibro-
vascular lesions.

14. C. Spontaneous involution of a neovascular trut
D. Haemorrhage due to traction.

15. Stage:- 4
• In some cases the neovascular tufts
continue to proliferate and bleed into
the vitreous.
Stage:- 5
• Extensive fibrovascular proliferative and
retinal detachment.

16. E.Extensive fibro-vascular proliferative
F. Peripheral retinal detachment

17. Inflammatory disease with possible
ischemia
o Sarcoidosis
o Retinal Vasculitis
o Intermediate uveitis
o Eales Disease
o Acute Retinal necrosis.

18. Miscellaneous
o Incontinentia pigmenti
o Autosomal dominant vitreo-retino-
choroido-pathy.
o Long standing retinal detachment.

19. Non-Proliferative Retinopathy
Asymptomatic Lesions:-
• Venous Tortuosity –is one of the 1st signs of
sickling and is due to peripheral arterio-
venous shunts.
• Silver-wiring of arterioles –in the peripheral
retina which represent occluded vessels.
• Salmon patches –are pink,pre-retinal {or}
superficial intra-retinal haemorrhages at the
equator,which lie adjacent to artioles and
usually resolve without sequelae.

20. Cont...
• Black Sunburts –are patches of peripheral
RPE hyperplasia.
• Macular depression sign –is an oval
depression of bright central macular reflex due
to atrophy and thinning of sensory retina.
• Peripheral retinal holes –and areas of
whitening similar to “white-without-pressure”.

22. Cont...
Symptomatic Lesions :-
• Macular arteriolar occlusion –occurs in
about 30% of patients.
• Acute CRAO –is rare.
• Choroidal vascular occlusion –may be seen
occasionally particularly in children.

23. Reference
Clinical Ophthalmology –Jack.J.Kanski
Comprehensive Ophthalmology –A.K Khurana