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Sudden onset blindness in sickle cell disease due to retinal artery
occlusion.Pediatr Blood
Cancer. 2007 Feb 2;
Central retinal
artery occlusion (CRAO) is a rare and potentially devastating cause
of acute blindness in sickle cell disease (SCD) that is unique
compared to classic sickle retinopathy. Few details related to this
complication in SCD are known, including its risk factors,
pathogenesis, presentation, treatment and outcomes. We present three
patients with SCD and retinal artery occlusion. The overall
variability in clinical presentation, treatment and prognosis
reported in the literature underscores the need for a greater
understanding of these factors as they relate to this complication
in SCD.
Sickle cell
disease and retinal damage: a study of 38 cases at the African
Tropical Ophthalmology Institute (IOTA) in Bamako.Med
Trop (Mars). 2006 Jun;66(3):252-4.
The purpose
of this prospective study was to evaluate retinal damage in patients
with sickle cell disease and its links with the different genotypic
forms of the disease in patients consulting at the African Tropical
Ophthalmology Institute (IOTA). A total of 38 patients with the HbS
gene were included over a 12-month study period. Retinal damage was
assessed by a computerised angiofluorography in 31 patients. Of the
38 patients studied, 71% had sickle cell disease (SC), 21% had
sickle cell trait (AS) and 8% had sickle cell anemia (SS).
Sixty-eight percent of patients (n = 21) presented sickle cell
retinopathy. The age group with the highest prevalence of
proliferative neovascularisation was between 26 and 35 years.
Retinopathy was more frequent in SC patients than AS patients: 90%
(n = 19) versus 10% (n = 2). None of the 3 SS patients presented
retinopathy. Retinal neovascularisation was the most common finding
in the 27 affected eyes. This study confirms the frequency and
severity of retinal damage in patients with the HbS haemoglobin,
particularly among young people with double heterozygous disease
(SC) in the tropical African environment. Treatment of this disorder
is largely unavailable to patients in sub-Saharan Africa except at
the major eye care centres. An early screening and management
programme for retinal damage related to SC would reduce ocular
complications and optimise visual efficiency in these young active
patients.
Ocular
morbidity from sickle cell disease in a Nigerian cohort.Niger
Postgrad Med J. 2005 Dec;12(4):241-4.
Sickle cell
Retinopathy is increasingly being recognised as a cause of
significant ocular morbidity and blindness in Africa south of the
Sahara. This study looked for retinopathy in a cohort of 90
Nigerians with Sickle Cell Disease (SCD). Method: The cohort
consisted of black Nigerians from the Hausa-Fulani, Ibo and Yoruba,
as well as other minority ethnic groups resident in the Federal
Capital Territory aged between 5-36 yr. 88 patients were SS and only
2 SC. Results: SCD related posterior lesions were seen in 22
patients (24%). Of these, 19 cases (21%) had Non Proliferative
Sickle Retinopathy (NPSR) while 5 (5.6%) had Proliferative Sickle
Retinopathy (PSR) in various stages of development, and 2 had both
PSR and NPSR. Patients with PSR are at risk of blindness from
vitreous haemorrhage and tractional retinal detachment. A
14-year-old male with arterio-venous anastomosis was the youngest
with PSR while the most advanced PSR lesion was a sea fan in a
25-year-old female. Conclusions: standard treatment consisting of
photocoagulation and/or vitrectomy is not available in many eye
centres in sub-Saharan Africa and steps need to be taken to improve
this situation. The role of anti-sickling remedies, if any, is the
subject of ongoing investigations. Our findings with NIPRISAN, a
phytomedicinal preparation currently undergoing trials, will be
reported subsequently.
Incidence and
natural history of proliferative sickle cell retinopathy:
observations from a cohort study.Ophthalmology.
2005 Nov;112(11):1869-75. Epub 2005 Sep 19.
OBJECTIVE:
To describe the incidence, prevalence, and natural history of
proliferative sickle cell retinopathy (PSR). DESIGN: Prospective
longitudinal study over 20 years. PARTICIPANTS: Newborn screening of
100000 consecutive deliveries from 1973 to 1981 identified 315
children with homozygous sickle cell (SS) disease and 201 with
SS-hemoglobin C (SC) disease. By the age of 5 years, 307 SS patients
and 166 SC patients were alive and living in Jamaica and were
recruited for this ophthalmic study. METHODS: Description of retinal
vascular changes on annual angiography and angioscopy. MAIN OUTCOME
MEASURES: Incidence and prevalence of PSR and its behavior on
follow-up. Progression of PSR was investigated using the number of
eyes affected (none, one, both) and the interval until PSR onset.
RESULTS: At last review in January 2000, PSR had developed in 59
patients (14 SS, 45 SC), unilaterally in 36 patients and bilaterally
in 23. Incidence increased with age in both genotypes, with crude
annual incidence rates of 0.5 cases (95% confidence interval [CI],
0.3-0.8) per 100 SS subjects and 2.5 cases (95% CI, 1.9-3.3) per 100
SC subjects. Prevalence was greater in SC disease, and by the ages
of 24 to 26 years, PSR had occurred in 43% subjects with SC disease
and in 14% subjects with SS disease. Patients with unilateral PSR
had a 16% (11% SS, 17% SC) probability of regressing to no PSR and a
14% (16% SS, 13% SC) probability of progressing to bilateral PSR.
Those with bilateral PSR had an 8% (8% SS, 8% SC) probability of
regressing to unilateral PSR and a 1% (0 SS, 2% SC) probability of
regressing to a PSR-free state. Irretrievable visual loss occurred
in only 1 of 82 PSR-affected eyes, and 1 required detachment surgery
and recovered normal visual acuity. CONCLUSIONS: Longitudinal
observations over 20 years in a cohort of patients followed from
birth confirms a greater incidence and severity of PSR in SC
disease, and shows that spontaneous regression occurred in 32% of
PSR-affected eyes. Permanent visual loss was uncommon in subjects
observed up to the age of 26 years.
Retinopathy
as a sickle-cell trait: myth or reality?
J Fr
Ophtalmol. 2004 Nov;27(9 Pt 1):1025-30.
INTRODUCTION: The retinopathy of sickle cell diseases is an ischemic
retinopathy that occurs frequently in the major forms of HbSS and
HbSC sickle cell diseases. The retinopathy of sickle trait HbAS has
not been described extensively. PATIENTS AND METHODS: The aim of
this study was to describe the retinal characteristics and thus gain
better knowledge of sickle trait HbAS retinopathy. Seventy HbAS
patients had a complete ocular examination including fluorescein
angiography. RESULTS: Seventy percent of the patients had retinal
lesions, with 49.3% non-vasoproliferative lesions, 22.7%
prevasoproliferative lesions and 2.7% neovascular lesions.
DISCUSSION AND CONCLUSION: Retinopathy is associated with the HbAS
sickle cell trait, but it is less serious than in the major forms of
sickle cell syndrome.
When should children and young adults with sickle cell disease be
referred for eye assessment?Afr
J Med Med Sci. 2001 Dec;30(4):261-3
Children and
young adults who suffer from sickle cell disease (SCD) are at risk
of blindness from retinopathy and other complications. The incidence
of proliferative retinopathy in SCD patients varies from 5 to 10%
depending on the genotype, being commoner in SC than SS and S-thal.
'Sudden' blinding sequelae such as vitreous haemorrhage and
tractional retinal detachment can eventuate from
vasculo-proliferative retinal lesions, known as sea fans, in
otherwise 'quiet' eyes. This risk can be minimised considerably if
the lesions are detected in a timely fashion and treated, usually
with laser photocoagulation and possibly with cryotherapy. This
communication aims, by a review of relevant literature and through
our original data, to highlight a time frame for the development of
proliferative sickle retinopathy to enable paediatricians decide on
an appropriate time of referral for ophthalmic assessment. Ninety
patients with SCD (88 SS, 2 SC) aged 5-36 years were examined for
anterior and posterior ocular signs of SCD using dilated binocular
indirect ophthalmoscopy. Other relevant literature was reviewed.
Twenty-four percent of these patients had some form of SCD related
posterior pathology, 5.6% of which was pre-proliferative or
proliferative. This included a 14-year-old SS patient with arterio-venous
anastomosis. The literature reveals that patients begin to exhibit
evidence of proliferative retinopathy from about the age of 10 and
the frequency tends to increase with age. However, though rare,
vitreous haemorrhage has been known to occur below the age of 20.
Children with SCD should, from about the age of ten, be referred for
at least biennial dilated binocular indirect ophthalmoscopy
preferably with fluorescein angiography if such facilities are
available, so that neovascular lesions can be treated before
blinding sequelae occur. From the age of 20, the frequency of eye
examination should increase to yearly. Antisickling remedies, such
as NIPRISAN may be beneficial in prophylaxis.
Retinopathy in sickle cell trait: does it exist?Can
J Ophthalmol. 2003 Feb;38(1):46-51.
BACKGROUND: Patients with sickle cell trait and concomitant systemic
disease are known to be at risk for proliferative retinopathy.
However, there are reports of retinopathy in patients with sickle
cell trait without systemic disease. There are no population-based
studies addressing the risk of sickle cell retinopathy in this
group. We performed a study to clarify the relation between sickle
cell trait and retinopathy in healthy subjects. METHODS: We reviewed
the medical records of 100 children with sickle cell disease who
attended the Sickle Cell Clinic at the Hospital for Sick Children,
Toronto. We then contacted 200 parents with sickle cell trait, of
whom 32 agreed to participate in the study. All participants were
proven to have hemoglobin AS status with prior hemoglobin
electrophoresis. An ophthalmologic history was obtained, and a
complete ophthalmologic examination was performed. We defined sickle
cell retinopathy as any salmon patch hemorrhages, iridescent spots,
black sunbursts, retinal neovascularization or retinal detachment.
The evaluation also included attempts to identify the more subtle
signs of sickle cell retinopathy, such as optic nerve head vascular
changes, vascular tortuosity, macular changes (e.g., microaneurysms
and vascular loops) and peripheral arteriovenous anastamoses. Blood
samples were obtained for complete blood count, reticulocyte count
and smear. RESULTS: We found no cases of sickle cell retinopathy
among the 32 subjects. Ten of 30 subjects had a high reticulocyte
count (greater than 120 x 10(9)/L); however, there were no
associated eye findings in this subgroup. INTERPRETATION: Our
results indicate that there is no increased risk of retinopathy in
healthy people with sickle cell trait.
Clinical
implications of vascular growth factors in proliferative
retinopathies.Curr
Opin Ophthalmol. 1997 Jun;8(3):19-31.
Angiogenesis
is a fundamental component of normal development and pathologic
processes within the eye. Complications due to abnormal ocular
neovascularization remain the leading cause of visual loss
throughout the world today. Neovascularization and the associated
increase in vascular permeability are the underlying threats to
vision in such diverse conditions as diabetic retinopathy, retinal
vein occlusion, retinopathy of prematurity, exudative age-related
macular degeneration, sickle cell retinopathy, radiation
retinopathy, and numerous others. Although it has been appreciated
for nearly one-half century that the clinical findings associated
with ocular neovascularization suggest an etiology involving the
elaboration of growth factors, the exact molecules involved and
their mechanisms of action have remained incompletely understood.
Recent developments in this rapidly evolving field have begun to
elucidate the major factors responsible for modulating the
neovascularization common to these conditions and have significant
theoretic implications for the development of novel, nondestructive,
pharmacologic treatment modalities.
New
classification of peripheral retinal vascular changes in sickle cell
disease.Br
J Ophthalmol. 1994 Sep;78(9):681-9.
The systemic
complications of homozygous sickle cell disease (SS) are more severe
than in sickle cell haemoglobin C (SC) disease, and yet visual loss
due to proliferative retinopathy is more common in the latter. This
anomaly is unexplained. It is believed that proliferative disease
occurs in response to closure of the peripheral retinal vasculature,
yet a systematic longitudinal survey of the peripheral retinal
vascular bed has not been undertaken. In the Jamaica Sickle Cohort
study all subjects are scheduled to receive annual ocular
examination and fluorescein angiography. The results have now been
analysed in subjects with SS and SC disease using a new
classification system based on a comparison of the peripheral
retinal vascular bed with that recorded in the cohort with normal
haemoglobin (AA) genotype. The vascular patterns could be classified
as qualitatively normal (type I) or abnormal (type II). An abnormal
vascular pattern was identified more commonly with age, in a
significantly larger proportion of subjects with SC than SS disease,
and was associated with the development of proliferative disease. In
order to establish the dynamics of change, the angiograms were
analysed in the 18 subjects (24 eyes) who developed proliferative
disease. It is shown that a qualitatively normal vascular pattern
may be retained despite loss of capillary bed and posterior
displacement of the vascular border. A border which is qualitatively
abnormal does not revert to normal, and once abnormal, continuous
evolution may occur before development of proliferative lesions. The
peripheral border of the retinal vasculature was too peripheral to
photographed in 13 of the 24 eyes before it becoming qualitatively
abnormal. It is concluded that a normal border, if posterior,
results from gradual modification of the capillary bed and indicates
low risk of proliferative disease. A qualitatively abnormal vascular
border occurs as a radical alteration of retinal perfusion in
subjects in whom little modification of the vascular bed occurred
before the event, and signals risk of proliferative disease. This
classification system is useful in identifying the likelihood of
threat to vision in young Jamaicans with sickle cell disease, and
the higher frequency of proliferative retinopathy in SC can be
explained by the higher prevalence of a qualitatively abnormal
peripheral retinal vasculature.
Immunohistochemical insights into sickle cell retinopathy.Curr
Eye Res. 1994 Feb;13(2):125-38.
Dynamic vaso-occlusive
and vaso-proliferative events occur in sickle cell retinopathy.
Using streptavidin peroxidase immunohistochemistry, we investigated
changes in distribution and relative levels of components in the
fibrinolytic system and growth factors in retina and choroid from 2
sickle cell patients: a 20 month old SS patient and a 54 year old SC
patient. Antigen localization in the sickle cell patients was
compared to localization from 2 non-sickle cell, non-diabetic
control subjects. In the fibrinolytic system, tissue plasminogen
activator (tPA) localization and immunoreactivity were comparable in
all eyes, but plasminogen activator inhibitor-1 (PAI-1)
immunoreactivity was elevated within the walls of retinal vessels in
the sickle cell tissue. Immunoreactive fibrin was often observed
within the lumen of retinal and choroidal vessels and in choroidal
neo-vascularization (CNV) in sickle cell subjects. Blood vessels
containing fibrin generally exhibited elevated PAI-1
immunoreactivity. Von Willebrand's factor (vWf) and basic fibroblast
growth factor (bFGF) immunoreactivity in sickle cell patients were
elevated in choriocapillaris and the walls of some retinal vessels.
Transforming growth factor-beta 1 (TGF-beta 1) immunoreactivity was
significantly lower in sickle cell choriocapillaris than in
controls. In chorioretinal pigmented lesions of the SC patient, bFGF
and TGF-beta 1, beta 2, and beta 3 immunoreactivity was present
within migrating retinal pigment epithelial (RPE) cells. Our
interpretation of the data presented in this case study is that
fibrin deposition within retinal and choroidal vessels of sickle
cell subjects may occur due to elevated PAI-1 activity. Moreover,
vaso-occlusions of choroidal vessels may influence the expression of
growth factors in choriocapillaris endothelium, which could
stimulate formation of choroidal neovascularization. Finally,
fibrosis and gliosis in and near chorioretinal pigmented lesions may
be stimulated by RPE production of bFGF and TGF-beta's.
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