Sickle retinopathy in patients with sickle trait

The Association of Sickle-Cell Disorders With Diabetic Retinopathy: A Large Database Study

Purpose

To evaluate the association of sickle-cell disease (SCD) and sickle-cell trait (SCT) disease with diabetic retinopathy (DR) in patients with diabetes mellitus (DM).

Design

Population-based, retrospective cohort study utilizing data from the TriNetX Research Network, including 119 million patients across 80 health care organizations worldwide.

Participants

Diabetes mellitus patients (type 1 [T1DM] or 2 [T2DM]), with or without SCD and SCT, were included. Three cohorts were analyzed, including (1) DM patients without SCD, SCT, or sickle-cell/hemoglobin-C; (2) DM with SCD; and (3) DM with SCT.

Methods

All patients with DM were categorized into 3 cohorts based on the presence of SCD and SCT. Each cohort underwent 1:1 propensity score matching for demographics, blood glucose levels, hemoglobin A1C, and other relevant comorbidities.

Main Outcome Measures

Risk of DR in DM patients with and without SCD or SCT.

Results

There was no significant difference in the risk of any T1DR between those with and without SCD. However, for those with SCT, there was a notable twofold increased risk for T1-proliferative DR (PDR) (relative risk [RR]: 2.03; 95% confidence interval [CI]: 1.33-3.01). In contrast, there was an elevated risk for any T2DR in patients with SCD (RR: 1.50; 95% CI: 1.19-1.88), particularly due to higher PDR risks in T2DM patients (RR: 1.83; 95% CI: 1.29-2.60). The risk of mild to moderate T2DM non-PDR was also found to be higher in patients with SCT.

Conclusions

The risk of any DR was increased in T2DM patients with SCD or SCT, with increased risks for PDR in patients with SCT and T1DM. This indicates there may be a potential role of sickle-cell disorders in diabetic eye disease progression.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

PARACENTRAL ACUTE MIDDLE MACULOPATHY WITH SICKLE CELL TRAIT

PURPOSE

To report a case of paracentral acute middle maculopathy in a pediatric patient with sickle cell trait.

METHODS

The patient was evaluated with a comprehensive ophthalmic examination, optical coherence tomography, optical coherence tomography angiography, and fluorescein angiography.

RESULTS

Acute loss of vision occurred immediately after an uneventful scleral buckling procedure for retinal detachment in a 16-year-old female patient. Retinal imaging studies confirmed the occurrence of paracentral acute middle maculopathy, an ischemic condition characterized by infarction of the inner nuclear layer of the retina caused by hypoperfusion of the intermediate and deep capillary plexuses. Laboratory evaluation was only remarkable for sickle cell trait. Over a course of 3 months after the loss of vision, visual acuity improved from 20/1,000 to 20/20, and optical coherence tomography lesion resolved to a parafoveal area of inner and middle retinal layer thinning. Paracentral scotoma corresponding to the atrophic area persisted.

CONCLUSION

Dehydration because of the presurgical nil-per-os status and transient increase in intraocular pressure during the buckling surgery may have predisposed this patient with sickle cell trait to a sickling event that caused localized ischemia in the middle retina's end-capillaries. Avoiding long nil-per-os status, being mindful of transient intraocular pressure elevation during scleral buckling procedures, and presurgical hemoglobin electrophoresis in at-risk populations are recommended to prevent sickling attacks during retinal surgeries in individuals with sickle cell trait.

Central Retinal Artery Occlusion in a Young Patient With a Hidden Unusual Sickle Cell Trait

Sickle cell trait is considered a benign condition. Ophthalmic manifestations are infrequent but can result in significant visual deterioration. We present a case of a 33-year-old male, not known to have any medical illnesses, who presented to the ophthalmological emergency room complaining of a sudden onset of painless and profound left eye vision loss for 12 hours. The patient denied any medication use, past eye trauma, or surgery. On detailed ophthalmologic examination, the best-corrected visual acuity (BCVA) was 20/20 in the right eye and hand movement in the left eye. Dilated fundus examination of the left eye showed a central retinal artery occlusion (CRAO) with pale, white retinal swelling and a macular cherry-red spot. Fundus fluorescein angiography showed delayed arterial filling with persistently reduced macular perfusion. CRAO was diagnosed in an otherwise healthy young male. Systemic workup was negative except for protein electrophoresis, which showed sickle cell trait, and HbA1C was 7.8%. Later, atrophic macular changes with a pale optic disc were observed, and BCVA was reduced to light perception. CRAO in young patients amounts to diverse causes, which require extensive systemic workup. In addition, the concurrence of the sickle cell trait with diabetes mellitus might have a role in CRAO development.

Proliferative Retinopathy Associated with Repeated High-Altitude Exposure in a Patient with Sickle Cell Trait

Broadhead Geoffrey K., Henry E. Wiley, David Peprah, Kenneth Olumba, and Alisa T. Thavikulwat. Proliferative retinopathy associated with repeated high-altitude exposure in a patient with sickle cell trait. High Alt Med Biol. 23:369-371, 2022.-Sickle cell trait (SCT), a carrier state characterized by one normal copy of the beta-globin gene (producing hemoglobin A) and one abnormal variant (producing hemoglobin S), is typically asymptomatic and very low risk for manifestations of hemoglobinopathy, including development of retinopathy. Reported cases of proliferative retinopathy in patients with SCT have occurred in the context of concurrent ocular or systemic disease. We report a case of an otherwise healthy patient with SCT who developed proliferative retinopathy requiring surgical intervention in the setting of significant exposure to high altitude through increased work hours as a flight attendant in the month leading to her presentation. Significant high-altitude exposure may contribute to development of retinopathy in patients with sickle trait. Practitioners should consider the possibility of sickle cell retinopathy in patients with sickle trait in these circumstances.

Severe Vaso-Occlusive and Ocular Decompression Retinopathy Revealing a Sickle Cell Trait in a Patient with Herpetic Uveitis

PURPOSE

To describe a patient with hypertensive herpetic uveitis complicated by arterial retinal occlusions and a decompression retinopathy revealing a sickle cell trait.

STUDY DESIGN

Case report.

RESULTS

A 24-year-old African man presented with a hypertensive herpetic keratouveitis. A brutal lowering of the intraocular pressure (IOP) by systemic acetazolamide resulted in a ocular decompression retinopathy and multiple arterial occlusions involving the macular and the mid-periphery retina. A hemoglobin electrophoresis revealed a sickle cell trait.

CONCLUSION

Under rare circumstances, vaso occlusive events can occur in patients with a sickle cell trait. We identified high IOP and acetazolamide to be responsible of an increased blood viscosity and a reduction of the vessels' caliber, resulting in sickling and arterial retinal occlusions. We recommend a thorough anamnesis and a sickle cell screening for patients of African or Mediterranean descent with acute elevated IOP, especially if they have to be treated with carbonic anhydrase inhibitors.Abbreviations: HbA: Hemoglobin A; HbS: Hemoglobin S; HSV1: Herpes Simplex Virus - 1; IOP: IntraOcular Pressure; OCT-A: OCT-Angiography; SD-OCT: Spectral Domain Optical Coherence Tomography.

Sickle Cell Trait Presenting as Unilateral Proliferative Retinopathy and Macular Thinning in a Pregnant Woman

Background

To report a case of a pregnant woman with sickle cell trait (SCT) who presented with unilateral proliferative sickle cell retinopathy. Case Presentation. A 26-year-old otherwise healthy pregnant woman presented with the complaint of visual loss in her left eye. The funduscopic examination showed vitreous hemorrhage, sea fan neovascularization, and pale optic disc. Optical coherence tomography revealed macular inner retinal layer thinning and foveal splaying (saucerization of the foveal pit). The investigations, including hemoglobin electrophoresis, verified the diagnosis of sickle cell trait. Blood pressure, fasting blood glucose tests, and tuberculin skin tests were normal. We treated the patient by peripheral retinal photocoagulation over the area of nonperfusion.

Conclusion

Even though the sickle cell trait is generally considered as a milder form of sickle cell disease without severe retinal manifestations, pregnancy should be considered as a trigger that can induce proliferative changes and foveal splaying in this group of patients.

Deep Learning Detection of Sea Fan Neovascularization From Ultra-Widefield Color Fundus Photographs of Patients With Sickle Cell Hemoglobinopathy

Importance

Adherence to screening for vision-threatening proliferative sickle cell retinopathy is limited among patients with sickle cell hemoglobinopathy despite guidelines recommending dilated fundus examinations beginning in childhood. An automated algorithm for detecting sea fan neovascularization from ultra-widefield color fundus photographs could expand access to rapid retinal evaluations to identify patients at risk of vision loss from proliferative sickle cell retinopathy.

Objective

To develop a deep learning system for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy.

Design, Setting, and Participants

In a cross-sectional study conducted at a single-institution, tertiary academic referral center, deidentified, retrospectively collected, ultra-widefield color fundus photographs from 190 adults with sickle cell hemoglobinopathy were independently graded by 2 masked retinal specialists for presence or absence of sea fan neovascularization. A third masked retinal specialist regraded images with discordant or indeterminate grades. Consensus retinal specialist reference standard grades were used to train a convolutional neural network to classify images for presence or absence of sea fan neovascularization. Participants included nondiabetic adults with sickle cell hemoglobinopathy receiving care from a Wilmer Eye Institute retinal specialist; the patients had received no previous laser or surgical treatment for sickle cell retinopathy and underwent imaging with ultra-widefield color fundus photographs between January 1, 2012, and January 30, 2019.

Interventions

Deidentified ultra-widefield color fundus photographs were retrospectively collected.

Main Outcomes and Measures

Sensitivity, specificity, and area under the receiver operating characteristic curve of the convolutional neural network for sea fan detection.

Results

A total of 1182 images from 190 patients were included. Of the 190 patients, 101 were women (53.2%), and the mean (SD) age at baseline was 36.2 (12.3) years; 119 patients (62.6%) had hemoglobin SS disease and 46 (24.2%) had hemoglobin SC disease. One hundred seventy-nine patients (94.2%) were of Black or African descent. Images with sea fan neovascularization were obtained in 57 patients (30.0%). The convolutional neural network had an area under the curve of 0.988 (95% CI, 0.969-0.999), with sensitivity of 97.4% (95% CI, 86.5%-99.9%) and specificity of 97.0% (95% CI, 93.5%-98.9%) for detecting sea fan neovascularization from ultra-widefield color fundus photographs.

Conclusions and Relevance

This study reports an automated system with high sensitivity and specificity for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy, with potential applications for improving screening for vision-threatening proliferative sickle cell retinopathy.

[Sickle cell trait complications: A case series of 6 patients]

INTRODUCTION

Patients with sickle cell trait (SCT) are commonly considered as asymptomatic carriers. However, some clinical manifestations may occur.

METHODS

Here we present a retrospective descriptive study about SCT subjects with at least one complication diagnosed in a sickle cell disease referral center, in Paris, between 2008 and 2019. We also performed a literature review on the complications of SCT subjects.

RESULTS

Six patients (between 19 and 65 years old) were included. SCT was already known only for 4 of them at the time of the complication. Four patients presented with a splenic infarct after a stay in high altitude or a plane trip, one of them was associated with papillary necrosis; one patient had isolated papillary necrosis, and the last one had splenic sequestration. These complications happened for most of them after exposure to an unusual situation of hypoxia or deshydratation. Five out of 6 patients had a marked elevated C reactive protein.

CONCLUSION

SCT may cause acute ischemic complications in a context of prolonged hypoxia or dehydration. The most commonly reported are the splenic infarct and the renal papillary necrosis. A study of hemoglobin should be considered in these clinical situations in patients with compatible ethnic origin.

Macular Infarction in a Patient with Sickle Cell Trait

PURPOSE

Sickle cell trait affects 8% of African Americans. Once believed to represent a benign carrier state, it has been linked to an increased risk of several of the pathological conditions that arise in sickle cell disease in at-risk individuals with hematologic and vascular comorbidities. Macular infarction is a known complication of sickle cell disease, but this report illustrates this unique presentation in a patient with sickle cell trait.

METHODS

Case report PATIENT:: A 74-year old African American male presented with the complaint of a central scotoma of the right eye.

RESULTS

Multimodal retinal imaging identified central macular infarction with severe inner retinal atrophy. Laboratory testing confirmed the presence of sickle cell trait. Other pertinent positives included low levels of protein C and protein S, untreated obstructive sleep apnea, and elevated levels of homocysteine in the setting of alcoholic liver cirrhosis and chronic kidney disease.

CONCLUSIONS

Ocular manifestations of sickle cell trait have most frequently been reported in individuals with systemic medical comorbidities that predispose to red blood cell sickling and vaso-occlusive disease. This case identifies a novel complication of sickle cell trait disorder, macular infarction, in a patient with comorbid associations.

Profound Presentation of Retinopathy in a Patient with Sickle Cell Trait and Diabetes Mellitus

This is a Photo Essay and does not have an abstract.

Peripheral Vaso-Occlusive Events Following Trauma in Patients With Sickle Cell Trait

Sickle cell trait (SCT) is a common hemoglobin variant, particularly in patients of African descent. Patients with SCT have an increased risk of adverse ocular events following trauma with subsequent elevated intraocular pressure (IOP). The authors describe three cases of young males with peripheral vaso-occlusive events following ocular trauma with subsequent elevated IOP. These cases demonstrate the importance of careful peripheral exams in young patients with SCT following trauma. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e84-e87.].

Bilateral Subperiosteal Hematoma and Orbital Compression Syndrome in Sickle Cell Disease

A 14-year-old boy with sickle cell disease presented with preseptal cellulitis findings as proptosis, eyelid edema, and hyperemia. His best corrected visual acuity in the right eye was 20/20 and 16/20 in the left eye. He had limited ductions in vertical and lateral gazes in both eyes. Bilateral venous tortuosity was observed in posterior segment examination. Orbital bone infarction and subperiosteal hematoma were seen in magnetic resonance imaging. He was diagnosed as having orbital compression syndrome secondary to vaso-occlusive crisis of sickle cell disease and was treated with intravenous ampicilin-sulbactam and methylprednisolone.

Automated retinal imaging and trend analysis - a tool for health monitoring

Most current diagnostic devices are expensive, require trained specialists to operate and gather static images with sparse data points. This leads to preventable diseases going undetected until late stage, resulting in greatly narrowed treatment options. This is especially true for retinal imaging. Future solutions are low cost, portable, self-administered by the patient, and capable of providing multiple data points, population analysis, and trending. This enables preventative interventions through mass accessibility, constant monitoring, and predictive modeling.

Unusual presentation of ocular trauma in sickle cell trait

Sickle cell trait is usually considered as a benign condition. However under certain adverse circumstances, it can give rise to vaso-occlusive features as in sickle cell disease. We present here two cases, both involving healthy young males, who developed retinal vaso-occlusive features following blunt ocular trauma. There was a rapid progression of the retinopathy with the development of proliferative changes in both patients and also vitreous hemorrhage in one patient, within 2 months of the trauma. The development of retinopathy was independent of raised intraocular pressure. Both patients were found to have sickle cell trait.

Association between Sickle Cell Trait and the Prevalence and Severity of Diabetic Retinopathy

Purpose

To determine whether Sickle cell trait (SCT) is associated with an increased severity of diabetic retinopathy.

Methods

This was a single center retrospective study case control study of 100 eyes of 100 patients with diabetes mellitus (DM) with SCT (SCT group) and 100 eyes of 100 age-matched patients with DM without SCT (control group). The main outcome measure was the difference in the prevalence of sight threatening DR [here defined as diabetic macular edema (DME) and/or proliferative diabetic retinopathy (PDR)], between the SCT and control groups. Secondary outcome measures included differences in visual acuity, ocular comorbidities, intraocular pressure, glycemic control as assessed by random blood glucose measurement, diabetes duration, nephropathy, hyperlipidemia and hypertension.

Results

The SCT group had statistically significantly shorter duration of DM (median [25% quartile] 15 [8.3] years versus 20 [14.7] years, respectively)(P<0.001) and presented with statistically better metabolic control (mean difference 1.6 mmol/l, (95% confidence interval [CI], 0.1–3.3;P = 0.03). The prevalence of PDR and/or DME was significantly lower in the SCT group (58%) compared to the control group, (95%)(P<0.001). The absence of SCT (adjusted odds ratio [AOR] = 24; 95% CI, 8–72; P<0.001) and longer duration of DM (AOR = 1.1 [95% CI, 1.02–1.13]; P = 0.003) were independent predictors of PDR and/or DME.

Conclusions

SCT seems to protect against the development and progression of DR. This may have implications for monitoring and screening. Prospective studies are required to confirm this association. If true, this association may indicate an increased blood glucose buffering capacity of abnormal hemoglobin.

Spontaneous central retinal artery occlusion in a teenager with sickle cell trait

Sickle cell trait (SCT) is traditionally considered a benign condition by ophthalmologists. Several studies have reported ocular complications in SCT, but these complications have been described as a consequence of trauma, exertion, and associated systemic disorders. We here in the report a case of an Arab teen boy, who presented with a sudden loss of vision in his left eye of 1 h duration. The ocular examination revealed acute central retinal artery occlusion. He underwent a series of laboratory and radiological investigations. The blood investigations revealed SCT and abnormal partial thromboplastin time. The fundus fluorescein angiography revealed abnormal retinal vascular perfusion. Marked blood rheological impairment and activation of the coagulation pathway can occur without any contributing factors in SCT leading to severe ocular complications. This is one of the young patients with spontaneous vascular occlusion in SCT.

Acute visual loss following dapsone-induced methemoglobinemia and hemolysis

OBJECTIVE

While methemoglobinemia is a possible complication of chronic dapsone therapy or of acute overdose, serious adverse manifestations related to methemoglobin formation remain rare. We present an unusual case with severe ischemic retinal injury.

CASE REPORT

A 30-year-old African woman presented with a sudden decrease of visual acuity secondary to retinal ischemia. She was chronically treated with dapsone (50 mg/day) for a dermatologic disease and denied any drug overdose. However, the determination of serum dapsone level on admission revealed a largely supratherapeutic concentration (20,044 μg/ml compared with 1-3.5 ± 0.5 μg/ml for therapeutic levels). The methemoglobin level at admission was 32% (sulfhemoglobin 1.2%), with hemoglobin level, 7.4 g/dl, schistocytes count, 2-5%, lactate dehydrogenase level, 580 IU/l, and haptoglobin level, < 10 mg/dl. The patient had both alpha-thalassemia and sickle cell trait. She was treated with methylene blue, vitamin C, and exchange transfusion. There was no improvement in visual symptoms over time.

CONCLUSIONS

In a patient with supratherapeutic serum levels of dapsone, the severity of visual injury was associated with dapsone-induced methemoglobinemia and hemolysis, and perhaps also with some hematologic predisposing factors.

La rétinopathie chez le porteur du trait drépanocytaire AS : mythe ou réalité ?

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.

Sickle cell trait and gender influence type 2 diabetic complications in African patients

BACKGROUND: Black and African patients with type 2 diabetes have a greater frequency and more severe vascular complications of the disease, even after correction for socioeconomic factors. Asymptomatic sickle cell trait (SCT; hemoglobin AS) is also common among black Africans and may independently cause endothelial damage, manifested as isolated target organ complication or infarction. We examined the possibility that patients with concurrent type 2 diabetes and SCT may be predisposed to more frequent or severe diabetic macro- or microvascular complications than those without SCT. METHODS: Fifty-two type 2 diabetic patients were divided into four groups, according to gender and hemoglobin genotype (normal: AA or SCT: AS). The groups were well matched for age and for clinical and demographic parameters. Diabetic complications were assessed in each patient and scored. Hemoglobin genotype was determined by hemoglobin-gel electrophoresis. Statistical comparisons were made between the groups. RESULTS: The composite complication score for vascular disease differed significantly according to gender and genotype (p<0.027 ANOVA). Male diabetics with SCT had a higher risk ratio (RR 1.6, p<0.02) for complications than those with normal hemoglobin; however, this was not the case with female diabetics. Among the male diabetics with SCT, there was a significantly greater proportion with proteinuria (p<0.02) or retinopathy (p<0.05) than among those with a normal hemoglobin genotype. Multiple regression analysis showed that gender and SCT were independent predictors of the vascular complication severity score and that exclusion of hemoglobin genotype weakened the predictability of the regression. A significantly higher proportion of male than female diabetics had at least one detectable complication. Systolic or diastolic blood pressure had no significant impact on the regressions. CONCLUSION: Male gender and SCT may adversely affect the expression of microvascular diabetic complications in Africans. Diabetic patients from populations predisposed to the sickle gene should be screened for the trait as part of their initial risk assessment. Large-scale studies on the impact of hemoglobin genotype on diabetic complications are clearly indicated.

Albuminuria in Afro-Caribbeans with Type 2 diabetes mellitus: is the sickle cell trait a risk factor?

AIMS

To determine the prevalence of albuminuria [raised albumin-creatinine ratio (ACR)] in an out-patient population of Afro-Caribbeans with Type 2 diabetes mellitus (DM) and to determine if the possession of the sickle cell trait (SCT) is a risk factor.

PATIENTS AND METHODS

The ACR in a morning urine sample was determined in each of 181 Afro-Caribbeans with Type 2 DM attending the out-patient clinic at King's Diabetes Centre of King's College Hospital, London. The subjects were genotyped for the SCT, Haemoglobin AS (HbAS).

RESULTS

Although a raised ACR was demonstrated more frequently in those with the SCT than in those without, with an odds ratio of 1.19, this was not statistically significant (P = 0.68).

CONCLUSIONS

In this study the possession of the SCT does not appear to play a significant role in the development of albuminuria. However, a larger study is needed to clarify its role as a risk factor for development of albuminuria in Afro-Caribbeans with Type 2 DM.

Retinopathy in sickle cell trait: does it exist?

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.

Benign idiopathic haemorrhagic retinopathy

PURPOSE

To describe a new condition characterised by an unusual unilateral idiopathic haemorrhagic retinopathy.

METHODS

A review is presented of patient histories from 5 patients with acute-onset unilateral idiopathic haemorrhagic retinopathy, including results of ophthalmological, haematological and fluorescein angiographic examinations.

RESULTS

All patients had an extensive deep blot haemorrhagic retinopathy without significant vascular signs or abnormal optic discs. In 4 cases the haemorrhage was sufficiently severe to break through into the vitreous. Fluorescein angiography demonstrated normal arteriovenous flow, without capillary non-perfusion, vessel or disc leakage. Disc swelling, macular oedema and cotton wool spots were not seen at any stage in these patients. All patients recovered the visual acuity in the affected eye by 4 months. Systemic examination in all cases was unremarkable.

CONCLUSION

This distinct and rare form of retinopathy is important to define since it has a good prognosis without treatment.

Latent proliferative sickle cell retinopathy in sickle cell trait

PURPOSE

To describe a patient with sickle cell trait who developed latent proliferative sickle cell retinopathy after mild blunt trauma.

METHOD

Case Report. A 20-year-old man with unilateral Stage 3 sickle retinopathy associated with an ischaemic ridge presenting three years after the initial mild blunt ocular trauma.

RESULTS

Fundus examination of the left eye showed an ischaemic ridge delineating avascular from vascular retina. Fluorescein angiography of the left eye showed an avascular peripheral retina and multiple sea fan neovascularization. Blood studies showed him to be Hb AS.

CONCLUSIONS

In our patient the proliferative changes were the result of his initial mild trauma associated with an increase in the intraocular pressure. The latent development of the sea-fan neovascularization associated with an ischaemic ridge is unusual. Advice about potential complications to patients with Hb AS after ocular trauma is advocated.

Retinopathy in haemoglobin C trait

Retinopathy associated with sickle-C and sickle cell disease is well described. Sickle trait and haemoglobin C trait are generally considered benign conditions, with infrequent systemic manifestations. Rare cases of retinopathy in sickle trait, in the presence of contributory factors, exist and we recently reported three such patients. The occurrence of retinopathy in haemoglobin C trait is even less well documented. Haemoglobin C does not cause red blood cell sickling but is known to decrease erythrocyte plasticity and increase blood viscosity. We report three cases in which haemoglobin C trait was associated with significant peripheral vascular occlusion and seafan formation (confirmed by fluorescein angiography) similar to that seen in sickle retinopathy. Two patients had coexistent systemic disease (hypertension and diabetes mellitus). Vitreous haemorrhage was the presenting feature in two patients. It is evident that haemoglobin C trait may be associated with sight-threatening complications.