New classification of peripheral retinal vascular changes in sickle cell disease

Advances in sickle cell retinopathy screening techniques, tests, and practices: A systematic review

Sickle cell retinopathy (SCR) is a progressive, sight-threatening ophthalmic complication of sickle cell disease (SCD). Current SCR screening focuses on the detection of pathologic sea fan neovascularization, the first sign of proliferative sickle cell retinopathy (PSR). If untreated, PSR can lead to severe visual impairment and blindness through progression to vitreous hemorrhage and/or retinal detachment. SCR screening with dilated fundus examination (DFE) is recommended every 1-2 years starting at age 10, but data underlying this recommendation are of poor quality and based upon expert consensus. We performed a systematic review to characterize imaging techniques, laboratory-based tests, and clinical practices for SCR screening. This PROSPERO-registered systematic review included relevant texts identified through predetermined searches in online databases. Collected test accuracy data facilitated the calculation of likelihood ratios. Forty-four studies evaluating 4928 patients were included. DFE demonstrated moderate test accuracy (LR+ of 8.0, LR- of 0.3). Ultra-widefield-fundus photography demonstrated superior accuracy (LR+ 32.5, LR- 0.03). Optical coherence tomography angiography applications were highly accurate for PSR identification (machine learning LR+ 32.5, LR- 0.03; human grader LR+ 2.8-213.1, LR- 0.1-0.2). Most techniques and tests were more accurate at detecting PSR than staging SCR or detecting lower-grade SCR. Our findings support the integration of advanced image-based approaches, such as computer-based image analysis and ultra-wide-field fundus imaging, for SCR screening in SCD patients given the superior accuracy in PSR detection compared with the current standard of care. Rigorous SCR screening implementation studies are needed to support evidence-based SCR screening recommendations.

Proliferative Sickle Cell Retinopathy in the Retinal Periphery Detected by Ultra-Widefield Imaging: A Case Report

Sickle cell proliferative retinopathy usually presents first in the peripheral retina and the ability to extend and enhance our visualization of the peripheral retina would allow for superior clinical decision-making. In our practice, we had a 28-year-old patient diagnosed with major sickle cell disease of the homozygous type SS (HbSS) that presented with sickle cell proliferative retinopathy detected by ultra-widefield imaging in the nasal side of the left fundus. At follow-up, neovascularization was detected in the extreme nasal periphery of the left eye by ultra-widefield imaging fluorescein angiography with right gaze. The case was graded as Goldberg stage 3, and the patient was administered photocoagulation treatment. With further advancements in the quality and modality of peripheral retinal imaging, novel proliferative lesions can be detected and appropriately managed much earlier than was previously possible. Ultra-widefield imaging allows for the visualization of the central 200 degrees of the retina but, with gaze view, peripheral retina beyond 200 degrees can be reached.

Laser therapy for retinopathy in sickle cell disease

BACKGROUND

Sickle cell disease (SCD) includes a group of inherited haemoglobinopathies affecting multiple organs including the eyes. Some people with SCD develop ocular manifestations. Vision-threatening complications are mainly due to proliferative sickle retinopathy, which is characterised by proliferation of new blood vessels. Laser photocoagulation is widely applicable in proliferative retinopathies. It is important to evaluate the efficacy and safety of laser photocoagulation in the treatment of proliferative sickle retinopathy (PSR) to prevent sight-threatening complications.

OBJECTIVES

To evaluate the effectiveness of various techniques of laser photocoagulation therapy in SCD-related proliferative retinopathy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 4 July 2022. We also searched the following resources (26 June 2022): Latin American and Caribbean Health Science Literature Database (LILACS); WHO International Clinical Trials Registry Platforms (ICTRP); and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials comparing laser photocoagulation to no treatment in children and adults with SCD.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and risk of bias of the included trials; we extracted and analysed data, contacting trial authors for additional information. We assessed the certainty of the evidence using the GRADE criteria.

MAIN RESULTS

We included three trials (414 eyes of 339 children and adults) comparing the efficacy and safety of laser photocoagulation to no therapy in people with PSR. There were 160 males and 179 females ranging in age from 13 to 67 years. The trials used different laser photocoagulation techniques; one single-centre trial employed sectoral scatter laser photocoagulation using an argon laser; a two-centre trial employed feeder vessel coagulation using argon laser in one centre and xenon arc in the second centre; while a third trial employed focal scatter laser photocoagulation using argon laser. The mean follow-up periods were 21 to 32 months in one trial, 42 to 47 months in a second, and 48 months in the third. Two trials had a high risk of allocation bias due to the randomisation method for participants with bilateral disease; the third trial had an unclear risk of selection bias. One trial was at risk of reporting bias. Given the unit of analysis is the eye rather than the individual, we chose to report the data narratively. Using sectoral scatter laser photocoagulation, one trial (174 eyes) reported no difference between groups for complete regression of PSR: 30.2% in the laser group and 22.4% in the control group. The same trial also reported no difference between groups in the development of new PSR: 34.3% of lasered eyes and 41.3% of control eyes (very low-certainty evidence). The two-centre trial using feeder vessel coagulation, only presented data at follow-up for one centre (mean period of nine years) and reported the development of new sea fan in 48.0% in the treated and 45.0% in the control group; no statistical significance (P = 0.64). A third trial reported regression in 55% of the laser group versus 28.6% of controls and progression of PSR in 10.5% of treated versus 25.7% of control eyes. We graded the evidence for these two primary outcomes as very low-certainty evidence. The sectoral scatter laser photocoagulation trial reported visual loss in 3.0% of treated eyes (mean follow-up 47 months) versus 12.0% of controlled eyes (mean follow-up 42 months) (P = 0.019). The feeder vessel coagulation trial reported visual loss in 1.14% of the laser group and 7.5% of the control group (mean follow-up 26 months at one site and 32 months in another) (P = 0.07). The focal scatter laser photocoagulation trial (mean follow-up of four years) reported that 72/73 eyes had the same visual acuity, while visual loss was seen in only one eye from the control group. We graded the certainty of the evidence as very low. The sectoral scatter laser trial detected vitreous haemorrhage in 12.0% of the laser group and 25.3% of control with a mean follow-up of 42 (control) to 47 months (treated) (P ≤ 0.5). The two-centre feeder vessel coagulation trial observed vitreous haemorrhage in 3.4% treated eyes (mean follow-up 26 months) versus 27.5% control eyes (mean follow-up 32 months); one centre (mean follow-up nine years) reported vitreous haemorrhage in 1/25 eyes (4.0%) in the treatment group and 9/20 eyes (45.0%) in the control group (P = 0.002). The scatter laser photocoagulation trial reported that vitreous haemorrhage was not seen in the treated group compared to 6/35 (17.1%) eyes in the control group and appeared only in the grades B and (PSR) stage III) (P < 0.05). We graded evidence for this outcome as low-certainty. Regarding adverse effects, only one occurrence of retinal tear was reported. All three trials reported on retinal detachment, with no significance across the treatment and control groups (low-certainty evidence). One trial reported on choroidal neovascularization, with treatment with xenon arc found to be associated with a significantly higher risk, but visual loss related to this complication is uncommon with long-term follow-up of three years or more. The included trials did not report on other adverse effects or quality of life.

AUTHORS' CONCLUSIONS

Our conclusions are based on the data from three trials (two of which were conducted over 30 years ago). Given the limited evidence available, which we assessed to be of low- or very low-certainty, we are uncertain whether laser therapy for sickle cell retinopathy improves the outcomes measured in this review. This treatment does not appear to have an effect on clinical outcomes such as regression of PSR and development of new incidences. No evidence is available assessing efficacy in relation to patient-important outcomes (such as quality of life or the loss of a driving licence).  Further research is needed to examine the safety of laser treatment compared to other interventions such as intravitreal injection of anti-vascular endothelial growth factors (VEGFs) . Patient-important outcomes as well as cost-effectiveness should be addressed.

Artificial intelligence for improving sickle cell retinopathy diagnosis and management

Sickle cell retinopathy is often initially asymptomatic even in proliferative stages, but can progress to cause vision loss due to vitreous haemorrhages or tractional retinal detachments. Challenges with access and adherence to screening dilated fundus examinations, particularly in medically underserved areas where the burden of sickle cell disease is highest, highlight the need for novel approaches to screening for patients with vision-threatening sickle cell retinopathy. This article reviews the existing literature on and suggests future research directions for coupling artificial intelligence with multimodal retinal imaging to expand access to automated, accurate, imaging-based screening for sickle cell retinopathy. Given the variability in retinal specialist practice patterns with regards to monitoring and treatment of sickle cell retinopathy, we also discuss recent progress toward development of machine learning models that can quantitatively track disease progression over time. These artificial intelligence-based applications have great potential for informing evidence-based and resource-efficient clinical diagnosis and management of sickle cell retinopathy.

Hemoglobinopathies: ocular manifestations in children and adolescents

Hemoglobinopathies are genetic disorders that lead to abnormal structure of the hemoglobin molecule. Sickle cell disease, the most common inherited blood disorder, is characterized by defective oxygen transport. Almost every part of the eye can be affected by sickle cell disease; however, proliferative sickle cell retinopathy is the primary cause of vision loss, either from vitreous hemorrhage or retinal detachment. Here we review the various manifestations of hemoglobinopathies on the eyes of children and adolescents, with a specific focus on sickle cell disease and its different phenotypes. Newer, more sensitive ophthalmological imaging modalities, including ultra-widefield fluorescein angiography, spectral-domain optical coherence tomography, and optical coherence tomography angiography, are available. These sensitive modalities allow for a more thorough examination of the retinal periphery where sickle cell retinopathy is often present. Utilization of such modalities will help with the early detection of the disease in children, which provide a better understanding of the pathogenesis of the disease and guide future screening and treatment regimens.

UTILITY OF ULTRA-WIDEFIELD RETINAL IMAGING FOR THE STAGING AND MANAGEMENT OF SICKLE CELL RETINOPATHY

PURPOSE

To determine whether ultra-widefield (UWF) retinal imaging changes the staging or management of sickle cell retinopathy compared with clinical examination.

METHODS

Prospective, observational study including patients with sickle cell disease. All patients underwent dilated fundus examination by a fellowship-trained retina specialist, as well as UWF fundus photography (FF) and fluorescein angiography (FA). Sickle retinopathy stage and treatment recommendation per eye were determined after clinical examination, UWF-FF, and UWF-FA, respectively, and differences in retinopathy stage and treatment recommendation were compared.

RESULTS

A total of 70 eyes from 35 patients (17 women, 48.6%), mean age 30.4 years, were included. Sickle genotypes included 26 patients with sickle SS (74.3%), 7 SC (20.0%), and 2 β(+)thalassemia (5.7%). Based on examination, most eyes (42/70; 60.0%) had no visible retinopathy. Based on UWF-FF, about half of the eyes were found to be Goldberg Stage 2 or above (36/70; 51.4%). Based on UWF-FA, nearly all eyes were Goldberg Stage 2 or above (63/70; 90%). However, clinical examination reliably detected neovascularization, and in no case did the addition of UWF imaging change management relative to examination alone.

CONCLUSION

Ultra-widefield imaging detects a higher stage of sickle cell retinopathy compared with clinical examination alone, but these differences may not be clinically significant.

[Sickle cell retinopathy in children: Report of 42 cases]

We aimed to describe the epidemiological, etiological and clinical features, treatment and clinical course of sickle cell retinopathy in children and to determine the risk factors for serious involvement.

METHODS

This was a retrospective study including all children diagnosed with sickle cell retinopathy. Epidemiological, clinical and therapeutic characteristics, as well as clinical course, were analysed retrospectively by chart review. Two groups were defined: Group 1 (Goldberg stage 1 and 2); Group 2 (Goldberg stage 3, 4 and 5). In order to identify factors independently associated with severe sickle cell retinopathy, we conducted a logistic regression analysis in descending order.

RESULTS

The frequency of sickle cell retinopathy was 14.48%. Forty-two patients (84 eyes) were included; among them 23 boys and 19 girls, aged 10 to 17 with a mean age of 14±1.98 years. Twenty patients were of genotype SS, 11 patients of genotype SC, 8 Sβ and 3 SO Arab. The three patients in group 2 were all of SS genotype. The majority of patients (32) had an HbF level of less than 15%. All our patients had sickle cell retinopathy distributed as follows: 62% at stage 1; 31% at stage 2; 5% at stage 3 and 2% at stage 4. Multivariate analysis revealed a single risk factor independently linked to severe involvement - an HbF level<15%.

CONCLUSION

Retinopathy is a frequent complication of sickle cell disease which may lead to blindness. The HbF level is negatively correlated with severe involvement.

Wide-field imaging of sickle retinopathy

Background

Wide-field imaging is a newer retinal imaging technology, capturing up to 200 degrees of the retina in a single photograph. Individuals with sickle cell retinopathy commonly exhibit peripheral retinal ischemia. Patients with proliferative sickle cell retinopathy develop pathologic retinal neovascularization of the peripheral retina which may progress into sight-threatening sequelae of vitreous hemorrhage and/or retinal detachment. The purpose of this review is to provide an overview of current and future applications of wide-field retinal imaging for sickle cell retinopathy, and recommend indications for best use.

Main body

There are several advantages to wide-field imaging in the clinical management of sickle cell disease patients. Retrospective and prospective studies support the success of wide-field imaging in detecting more sickle cell induced retinal microvascular abnormalities than traditional non-wide-field imaging. Clinicians can easily capture a greater extent of the retinal periphery in a patient's clinical baseline imaging to follow the changes at an earlier point and determine the rate of progression over time. Wide-field imaging minimizes patient and photographer burden, necessitating less photos and technical skill to capture the peripheral retina. Minimizing the number of necessary images can be especially helpful for pediatric patients with sickle cell retinopathy. Wide-field imaging has already been successful in identifying new biomarkers and risk factors for the development of proliferative sickle cell retinopathy. While these advantages should be considered, clinicians need to perform a careful risk-benefit analysis before ordering this test. Although wide-field fluorescein angiography successfully detects additional pathologic abnormalities compared to traditional imaging, a recent research study suggests that peripheral changes differentially detected by wide-field imaging may not change clinical management for most sickle cell patients.

Conclusions

While wide-field imaging may not carry a clinically significant direct benefit to all patients, it shows future promise in expanding our knowledge of sickle cell retinopathy. Clinicians may monitor peripheral retinal pathology such as retinal ischemia and retinal neovascularization over progressive time points, and use sequential wide-field retinal images to monitor response to treatment. Future applications for wide-field imaging may include providing data to facilitate machine learning, and potential use in tele-ophthalmology screening for proliferative sickle retinopathy.

Relating retinal blood flow and vessel morphology in sickle cell retinopathy

Purpose

The purpose of the current study was to determine associations between retinal blood flow and vessel morphology metrics in sickle cell retinopathy (SCR) and healthy normal control (NC) subjects.

Methods

Optical coherence tomography angiography (OCTA) and Doppler OCT imaging were performed in 12 SCR (15 eyes) and 19 NC (26 eyes) subjects. Vessel tortuosity was measured using a dedicated image analysis algorithm applied to OCTA images. Vessel density and spacing between vessels were determined from OCTA images by a fractal dimension analysis method. Retinal blood flow was quantified using a phase-resolved technique applied to en face Doppler OCT images.

Results

There was a significant association between increased retinal blood flow and increased vessel tortuosity (P = 0.03). Furthermore, increased retinal blood flow was associated with increased vessel density (P = 0.03) and decreased spacing between small vessels (P = 0.01). There was no significant association between retinal blood flow and spacing between large vessels (P = 0.11). Vessel tortuosity and blood flow were increased, whereas spacing between small vessels was decreased in SCR compared to NC group (P ≤ 0.03). There were no significant differences in vessel density or spacing between large vessels between the SCR and NC groups (P ≥ 0.31).

Conclusions

Associations between retinal hemodynamics and vessel morphology were reported, providing better understanding of retinal pathophysiology and insight into potential quantitative biomarkers to evaluate SCR.

Sickle cell disease: Clinical presentation and management of a global health challenge

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease.

Sickle cell retinopathy: A literature review

Hemoglobinopathies are a group of hereditary diseases that cause quantitative or qualitative changes in the shape, function or synthesis of hemoglobin. One of the most common is sickle cell anemia, which, due to sickling of erythrocytes, causes vaso-occlusive phenomena. Among the possible ocular manifestations, the most representative is retinopathy, which can lead to blindness if left untreated. Therefore, periodic ophthalmologic monitoring of these patients is important for early diagnosis and adequate therapeutic management, which can be done localy by treating the lesions in the eyes, or systemically.

Retinal Photocoagulation for Proliferative Sickle Cell Retinopathy: A Prospective Clinical Trial with New Sea Fan Classification

Purpose

To compare the clinical outcome of stage III proliferative sickle cell retinopathy (PSR) treated by peripheral retinal scatter photocoagulation to natural course disease.

Methods

Long-term follow-up of 101 patients enrolled in a prospective trial of photocoagulation for PSR has been completed. Among 202 eyes of 101 patients enrolled at the University Eye Clinic of Créteil, 73 eyes showed a stage III PSR, which the authors further divided into five new grades (A, B, C, D, E) considering size, hemorrhage, fibrosis, and visible vessels. Grading was based on a three-mirror fundus examination, 360° color photographs, and fluorescein angiography. Mean follow-up was 4 years.

Results

Thirty-eight treated eyes and 35 untreated eyes were included in this study. The evolution was not statistically significant between treated and untreated groups concerning flat sea fan p<1 MPS disc area (grade A) or elevated sea fan with partial fibrosis (grade C). Progression and regression were compared between the two groups for grade B, resulting statistically significant (pp<0.05). Nine complications (13%) were observed, which only occurred in untreated patients with elevated sea fan and hemorrhage (grade B) or complete fibrosed sea fan with well defined vessels (grade E) (pp<0.05).

Conclusions

These data suggest that patients with grade A or C new sea fan classification should not be initially treated but observed.

New Ways to Detect Pediatric Sickle Cell Retinopathy: A Comprehensive Review

Sickle retinopathy reflects disease-related vascular injury of the eye, which can potentially result in visual loss from vitreous hemorrhage or retinal detachment. Here we review sickle retinopathy among children with sickle cell disease, describe the epidemiology, pediatric risk factors, pathophysiology, ocular findings, and treatment. Newer, more sensitive ophthalmological imaging modalities are available for retinal imaging, including ultra-widefield fluorescein angiography, spectral-domain optical coherence tomography, and optical coherence tomography angiography. Optical coherence tomography angiography provides a noninvasive view of retinal vascular layers that could previously not be imaged and can be quantified for comparative or prospective analyses. Ultra-widefield fluorescein angiography provides a more comprehensive view of the peripheral retina than traditional imaging techniques. Screening for retinopathy by standard fundoscopic imaging modalities detects a prevalence of approximately 10%. In contrast, these more sensitive methods allow for more sensitive examination that includes the retina perimeter where sickle retinopathy is often first detectable. Use of these new imaging modalities may detect a higher prevalence of early sickle pathology among children than has previously been reported. Earlier detection may help in better understanding the pathogenesis of sickle retinopathy and guide future screening and treatment paradigms.

Optical Coherence Tomography Angiography and Ultra-widefield Fluorescein Angiography for Early Detection of Adolescent Sickle Retinopathy

PURPOSE

Based on standard screening techniques, sickle retinopathy reportedly occurs in 10% of adolescents with sickle cell disease (SCD). We performed a prospective, observational clinical study to determine if ultra-widefield fluorescein angiography (UWFA), spectral-domain optical coherence tomography (SD-OCT), and optical coherence tomography angiography (OCT-A) detect more-frequent retinopathy in adolescents with SCD.

DESIGN

Cross-sectional study.

METHODS

Setting: Institutional.

SUBJECTS

Sixteen adolescents with SCD, aged 10-19 years (mean age 14.9 years), and 5 age-equivalent controls (mean age 17.4 years).

OBSERVATION PROCEDURES

Examinations including acuity, standard slit-lamp biomicroscopy, UWFA, SD-OCT, and OCT-A were performed.

MAIN OUTCOME MEASURES

Sickle retinopathy defined by biomicroscopic changes, Goldberg stages I-V, Penman scale, flow void on OCT-A, or macular thinning on SD-OCT.

RESULTS

While 22 of 32 SCD eyes (68.8%) had retinopathy on biomicroscopy, by UWFA 4 of 24 (16.7%) SCD eyes had peripheral arterial occlusion (Goldberg I), and 20 of 24 eyes (83.3%) had peripheral arteriovenous anastomoses (Goldberg II) in addition. No patients had Goldberg stages III-V. By SD-OCT and OCT-A, thinning of the macula and flow voids in both the superficial and deep retinal capillary plexus were found in 6 of 30 (20%) eyes.

CONCLUSIONS

All 24 eyes with adequate UWFA studies demonstrated sickle retinopathy. SD-OCT and OCT-A, which have not been previously reported in the adolescent population, detected abnormal macular thinning and flow abnormalities undetected by biomicroscopy. These findings suggest that pediatric sickle retinopathy may be more prevalent than previously suspected. If these findings are confirmed with larger cross-sectional and prospective analyses, these approaches may enhance early screening for sickle retinopathy.

Sickle cell retinopathy: improving care with a multidisciplinary approach

Sickle cell retinopathy (SCR) is the most representative ophthalmologic complication of sickle cell disease (SCD), a hemoglobinopathy affecting both adults and children. SCR presents a wide spectrum of manifestations and may even lead to irreversible vision loss if not properly diagnosed and treated at the earliest. Over the past decade, multidisciplinary research developments have focused upon systemic, genetic, and ocular risk factors of SCR, enabling the clinician to better diagnose and manage these patients. In addition, newer imaging and testing modalities, such as spectral domain-optical coherence tomography angiography, have resulted in the detection of subclinical retinopathy related to SCD. Innovative therapy includes intravitreal injection of an anti-vascular endothelial growth factor (eg, Lucentis^® [ranibizumab] or Eylea^® [aflibercept]) which appears comparatively safe and efficient, and may be combined with laser photocoagulation (LPC) for proliferative SCR. The effect of LPC alone does not significantly lead to the regression of advanced SCR, although it helps in avoiding hemorrhage and sight loss. This comprehensive article is based on 10-years retrospective (2007–2017) studies. It aims to present advances and recommendations in SCR theranostics while pointing out the requirement of combinatorial approaches for better management of SCR patients. To reach this goal, we identified and analyzed randomized original and review articles, clinical trials, non-randomized intervention studies, and observational studies using specified keywords in various databases (eg, Medline, Embase, Cochrane, ClinicalTrials.gov).

Laser therapy for retinopathy in sickle cell disease

BACKGROUND

Sickle cell disease includes a group of inherited haemoglobinopathies affecting multiple organs including the eyes. Some people with the disease develop ocular manifestations due to vaso-occlusion. Vision-threatening complications of sickle cell disease are mainly due to proliferative sickle retinopathy which is characterized by proliferation of new blood vessels. Laser photocoagulation is widely applicable in proliferative retinopathies such as proliferative sickle retinopathy and proliferative diabetic retinopathy. It is important to evaluate the efficacy and safety of laser photocoagulation in the treatment of proliferative sickle retinopathy to prevent sight-threatening complications.

OBJECTIVES

To evaluate the effectiveness of various techniques of laser photocoagulation therapy in sickle cell disease-related retinopathy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of last search: 21 September 2015.We also searched the following resources (24 March 2015): Latin American and Carribean Health Science Literature Database (LILACS); WHO International Clinical Trials Registry Platforms (ICTRP); and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials comparing laser photocoagulation to no treatment in children and adults.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, the risk of bias of the included trials and extracted and analysed data. We contacted the trial authors for additional information.

MAIN RESULTS

Two trials (341 eyes of 238 children and adults) were included comparing efficacy and safety of laser photocoagulation to no therapy in people with proliferative sickle retinopathy. There were 121 males and 117 females with an age range from 13 to 67 years. The laser photocoagulation technique used was different in the two trials; one single-centre trial employed sectoral scatter laser photocoagulation using an argon laser; and the second, two-centre trial, employed feeder vessel coagulation using argon laser in one centre and xenon arc in the second centre. The follow-up period ranged from a mean of 21 to 32 months in one trial and 42 to 47 months in the second. Both trials were at risk of selection bias (random sequence generation) because of the randomisation method employed for participants with bilateral disease. One study was considered to be at risk of reporting bias.Using sectoral scatter laser photocoagulation, one trial (174 eyes) reported that complete regression of proliferative sickle retinopathy was seen in 30.2% in the laser group and 22.4% in the control group (no difference between groups). The same trial reported the development of new proliferative sickle retinopathy in 34.3% of laser-treated eyes and in 41.3% of eyes given no treatment; again, there was no difference between treatment groups. The second trial, using feeder vessel coagulation, did not present full data for either treatment group for these outcomes.There was evidence from both trials (341 eyes) that laser photocoagulation using scatter laser or feeder vessel coagulation may prevent the loss of vision in eyes with proliferative sickle retinopathy (at median follow up of 21 to 47 months). Data from both trials indicated that laser treatment prevented the occurrence of vitreous haemorrhage with both argon and xenon laser; with the protective effect being greater with feeder vessel laser treatment compared to scatter photocoagulation.Regarding adverse effects, the incidence of retinal tear was minimal, with only one event reported. Combined data from both trials were available for 341 eyes; there was no difference between the laser and control arms for retinal detachment. In relation to choroidal neovascularization, treatment with xenon arc was found to be associated with a significantly higher risk, but visual loss related to this complication is uncommon with long-term follow up of three years or more.Data regarding quality of life and other adverse effects were not reported in the included trials.

AUTHORS' CONCLUSIONS

Our conclusions are based on the data from two trials conducted over 20 years ago. In the absence of further evidence, laser treatment for sickle cell disease-related retinopathy should be considered as a one of therapeutic options for preventing visual loss and vitreous haemorrhage. However, it does not appear to have a significant different effect on other clinical outcomes such as regression of proliferative sickle retinopathy and development of new ones. No evidence is available assessing efficacy in relation to patient-important outcomes (such as quality of life or the loss of a driving licence). There is limited evidence on safety, overall, scatter argon laser photocoagulation is superior in terms of adverse effects, although feeder vessel coagulation has a better effect in preventing vitreous haemorrhage. Further research is needed to examine the safety of laser treatment compared to other interventions such as intravitreal injection of anti-vascular endothelial growth factors. In addition, patient-important outcomes as well as cost-effectiveness should be addressed.

Regional morphology and pathophysiology of retinal vascular disease

Disturbances in the retinal vascular supply are involved in the pathophysiology of the most frequent diseases causing visual impairment and blindness in the Western World. These diseases are diagnosed by noting how morphological lesions in the retina vary in shape, size, location and dynamics, and subsequently concluding the presence of a specific disease entity. This diagnostic approach can be used to identify the site of a retinal vascular occlusion, to assess whether retinal diseases are primarily due to changes in the larger retinal vessels or the microcirculation, and to differentiate the relative involvement of the choroidal and the retinal vascular systems. However, a number of morphological manifestations of retinal vascular disease cannot presently be related to the underlying pathophysiology. The review concludes that there is a need for developing new methods for assessing vascular structure and function in the ciliary vascular system supplying the choroid and the optic nerve head. Presently, the study of these structures relies on imaging techniques with limited penetration and resolution into the tissue. Secondly, there is a need for studying oscillations in retinal vascular function occurring within days to weeks, and for studying regional manifestations of retinal vascular disease. This may constitute the basis for future research in retinal vascular pathophysiology and for the development of new treatment modalities to reduce blindness secondary to retinal vascular disease.

Detection and monitoring of sickle cell retinopathy using ultra wide-field color photography and fluorescein angiography

PURPOSE

In this study, we demonstrate the use of wide-field photography and fluorescein angiography to visualize the peripheral vascular changes and to identify patients with risk factors for developing proliferative sickle cell retinopathy.

METHODS

This is a retrospective case series of 12 eyes of 6 patients with sickle cell disease. Visual acuity testing, slit-lamp biomicroscopy, dilated fundus examinations, and noncontact wide-field fundus photography and fluorescein angiography using Optomap scanning laser ophthalmoscope (Optos, Marlborough, MA) were performed in all patients. The retinopathy was classified into proliferative and nonproliferative retinopathies, and the extent of retinopathy was measured in degrees. Wide-field images obtained using Optomap were compared with the derived seven-standard field images.

RESULTS

At the time of initial examination, 50% of the total eyes had proliferative retinopathy. All the peripheral retinas and vasculature were easily imaged within a single frame with Optomap. Six eyes met the high-risk criteria for developing proliferative changes. None of the eyes in our case series had tractional retinal detachment. The degrees of any type of sickle cell retinopathy and active neovascularization ranged from 20° to 360° and 10° to 60°, respectively. In all but one eye, wide-field images detected peripheral vascular changes missed on the seven-standard field photographs.

CONCLUSION

Wide-field fluorescein angiography and color photography enhance clinicians' ability to visualize peripheral vascular remodeling in sickle cell disease and to identify high-risk characteristics for proliferative sickle cell retinopathy.

PERIPHERAL VASCULAR ABNORMALITIES IN β-THALASSEMIA MAJOR DETECTED BY ULTRA WIDE-FIELD FUNDUS IMAGING

PURPOSE

To describe peripheral retinal vascular abnormalities in two patients with β-thalassemia major.

METHODS

Visual acuity testing, slit-lamp biomicroscopy, dilated fundus examination, ultra wide-field fundus photography, and fluorescein angiography were performed in two consecutive patients with β-thalassemia major.

RESULTS

Both patients had excellent visual acuity (20/20 and 20/25). Anterior segment examination was unremarkable. There were no lenticular changes noted in either patient. Dilated fundus examination was only remarkable for peripheral neovascular changes with preretinal hemorrhage in one patient and white without pressure in the other patient. Ultra wide-field fluorescein angiography revealed peripheral ischemia, vascular remodeling, active neovascularization, and arteriovenous anastomosis at the junction of perfused and nonperfused peripheral retina. One patient had sea fan neovascularization with active vitreous hemorrhage requiring peripheral laser photocoagulation.

CONCLUSION

As with patients with sickle cell disorder, patients with β-thalassemia major may require surveillance for peripheral vascular abnormalities, with treatment of these abnormalities before they result in permanent visual loss.

[Screening for sickle cell disease retinopathy in the north of France]

OBJECTIVE

To study the frequency and the severity of retinopathy in adult patients with sickle cell disease in the north of France.

PATIENTS AND METHODS

Patients with sickle cell disease aged more than 18 years old were consecutively referred for screening of sickle cell retinopathy in the ophthalmology department from December 2005 to March 2008. Complete ophthalmologic examination with dilated funduscopy was performed in each patient. Fluorescein angiography was performed in cases with ischemic retinopathy. Goldberg and Penman classifications were used to grade retinopathy severity.

RESULTS

Fifty-five patients (100 eyes) were included (26 S/S, 9 S/C, 12 S/B, 3 S/S with hereditary persistence of fetal hemoglobin). Sickle cell retinopathy is more severe in patients with the S/C genotype than the S/S and S/B genotypes. Proliferative retinopathy is more common in S/C patients than S/S and S/B patients (S/C vs S/S, p=0.001; S/C vs SB, p=0.01). A qualitatively abnormal vascular border (type II) is also more frequent in S/C patients than S/S and S/B patients (S/C vs S/S, p=0.001; S/C vs SB, p=0.01). No proliferative retinopathy was found in patients with S/S and hereditary persistence of fetal hemoglobin syndrome.

CONCLUSIONS

Screening is useful to detect sickle cell retinopathy, particularly in the adult population, to prevent complications from proliferative retinopathy.

Risk factors for conjunctival and retinal vessel alterations in sickle cell disease

PURPOSE

The aim of this study was to clarify whether the clinical, laboratory and genetic aspects of sickle cell disease (SCD) influence the occurrence of vessel alterations in the conjunctiva and retina.

METHODS

A total of 102 SCD patients underwent biomicroscopical and retinal examination, in addition to evaluations of haemoglobin (Hb) and haematocrit (Ht) levels, fetal haemoglobin (HbF) estimations, serum creatinine and albuminuria levels, glomerular filtration rate (GFR) values, phenotypes, beta-globin gene haplotypes and alpha-thalassaemia. The relationship between ocular vessel alterations and clinical, laboratory and genetic features were evaluated using chi-squared or Fisher tests and logistic regression analysis. In 13 patients on enalapril treatment, a second ophthalmological evaluation was performed after a 12-month period to evaluate the longitudinal effect of the drug on ocular vessels.

RESULTS

Conjunctival vessel alteration (CVA) was not influenced by age, gender, HbF estimation, serum creatinine and albuminuria levels, GFR values, beta-globin gene haplotypes or alpha-thalassaemia. However, increased frequencies of CVA were found in patients with Hb </= 9.0 g/dl, Ht </= 26.7% and sickle cell anaemia (SS) phenotype. Retinal vessel alteration (RVA) was identified only in patients aged 17 years or older. Enalapril did not demonstrate ocular vessel amelioration after 12-months of daily use.

CONCLUSION

The results indicate that lower Hb and Ht levels and SS phenotype are risk factors for CVA, and age over 17 years may be risk factors for RVA in SCD patients.

Incidence and natural history of proliferative sickle cell retinopathy: observations from a cohort study

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.

Malevolent ogbanje: recurrent reincarnation or sickle cell disease?

The Igbo of Nigeria believe that everyone is ogbanje (reincarnates) but malevolent ogbanje differ from others in being revenge-driven, chronically ill and engaging in repeated cycles of birth, death and reincarnation. This study examined culturally defined symptoms of 100 children classified as malevolent ogbanje; and investigated their family history and child mortality experience. There was concordance between cultural descriptions of malevolent ogbanje and symptoms as manifested in sickle cell patients. Hemoglobin analysis showed that 70 of the 100 children had sickle cell disease (SCD); while 68 families had death-related names. The symptoms associated with Igbo cases of reincarnation, high child mortality rates, and the high prevalence of sickle cell disease among children classified as malevolent ogbanje all support the conclusion that the symptomatology and early mortality experience are related to sickle cell. Names with themes of death were prevalent in families of children described as malevolent ogbanje. The findings are discussed with reference to cultural resistance to SCD as an explanation for malevolent ogbanje and the implications for the health care of children with SCD in Nigeria.

Pathophysiology of sickle cell disease

Sickle cell disease is caused by a mutation in the beta-globin chain of the haemoglobin molecule. Sickle haemoglobin, the result of this mutation, has the singular property of polymerizing when deoxygenated. Exactly how normal tissue perfusion is interrupted by abnormal sickle cells is complex and poorly understood. Despite genetic identity at the site of the sickle haemoglobin mutation, all patients with sickle cell anaemia are not affected equally by this disease. Secondary genetic determinants and acquired erythrocyte and vascular damage are likely to be central components of the pathophysiology of sickle cell anaemia.

Disorders of perfusion of the anterior segment of the eye

BACKGROUND

We have investigated the vascular perfusion of a wide variety of conditions of the anterior segment using fluorescein angiography.

METHODS

The conditions were classified and findings reported according to the system set out below. Patients underwent full ocular examination. Fluorescein angiography of the anterior segment was carried out when indicated to investigate iris atrophy and neovascularisation. Specular microscopy of the corneal endothelium was used to detect changes in this tissue.

RESULTS

The hypoperfusion was variable in degree and accompanied by varying degrees of iris hypoplasia and atrophy with neovascularisation. The degree of neovascularisation depended upon its rapidity of development, the pre-existing state of vascular perfusion and the underlying pathological condition.

CONCLUSIONS

Hypoperfusion with resultant ischaemia and neovascularisation is common in conditions of the anterior segment. An understanding of the changes is valuable in treating many conditions affecting the anterior segment. The changes observed may also occur elsewhere in the physical system and may be a significant part of the ageing process, either as scattered, disparate processes or as part of a general disease process.

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.

Ocular findings in Saudi Arabian patients with sickle cell disease

AIM

This study was set up to determine whether or not retinal changes occur in sickle cell disease in Saudi Arabian subjects with either the Benin, which exists in the south western part of the kingdom, or Asian haplotypes in the east, and to compare the findings with those in sickle cell disease in Jamaica.

METHODS

Retinal examination and fluorescein angiography were performed in 61 patients with SS disease (40 eastern, 20 south western, 1 central region) and 10 with sickle cell beta(0) thalassaemia.

RESULTS

Peripheral retinal vascular changes were common, and a qualitatively abnormal vascular border believed to imply risk of proliferative sickle retinography (PSR) was significantly more common in south western SS patients and PSR was shown in one of these. There were no differences in visual acuity, the presence of peripheral retinal patches, or the circumferential or posterior extent of peripheral retinal vessel closure between SS disease and sickle cell beta(0) thalassaemia or between SS disease in the two regions. Compared with the Jamaican Cohort Study, > 180 degrees of the peripheral retinal vasculature was seen significantly less frequent, suggesting factors inhibiting vascular remodeling in Saudi patients in early life.

CONCLUSION

Sickle cell disease in Saudi Arabia affects the retina and represents a potential threat to vision. Changes occur whatever the haplotype, and is similar to that observed in Jamaica.

Screening for ophthalmic manifestations of sickle cell disease in the United Kingdom

There are marked variations in the manifestations of sickle disease in different populations. The ocular complications of this condition amongst the Afro-Caribbeans living in the United Kingdom have not previously been reported. We present the preliminary results of an ophthalmic screening programme at King's College Hospital, London. One hundred eyes of 50 patients with sickle cell disease were assessed. Full ocular examination was performed including fundus fluorescein angiography. We have looked at the haematological and clinical profile of the patients involved as well as the number of days spent in hospital during the year preceding the eye examination. The incidence of grade II retinopathy was found to be significantly higher than grade I in SC disease. This concurs with the results of the Jamaican screening and confirms that these patients are at higher risk of visual impairment than those with SS disease. Our results also agree with the Jamaican experience which suggest that visual morbidity is mostly due to complications of proliferative sickle retinopathy (PSR). However, the findings in patients without proliferative changes are different; in particular, angioid streaks leading to disciforms are an important cause of visual loss in Jamaica, but were not seen in any of the 98 eyes examined in this study. No correlation was found between the grade of retinopathy and age, sex, systemic complications and various haematological parameters except for the percentage of haemoglobin F, which was significantly higher in patients with grade I (7.6) compared with grade II (4.2) retinopathy (p = 0.0127).