1
|
Nadelmann JB, Li Y, McGeehan B, Yu Y, VanderBeek BL. Systemic disease associations with angioid streaks in a large healthcare claims database. Eye (Lond) 2023; 37:1596-1601. [PMID: 35915234 PMCID: PMC10220014 DOI: 10.1038/s41433-022-02189-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 06/27/2022] [Accepted: 07/15/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND/OBJECTIVES To assess systemic associations of angioid streaks (AS) using a large US healthcare database. SUBJECTS/METHODS A retrospective cross-sectional study was conducted of patients diagnosed with AS in a large, national US insurer from 2000-2019. Cases were matched 1:5 to controls. The prevalence rates of established associated disease states and other systemic diseases were calculated and compared using logistic regression. Additionally, the rate of anti-VEGF treatment was assessed as a proxy for the incidence of choroidal neovascularization (CNV). RESULTS One thousand eight hundred fifty-two cases of AS and 9028 matched controls were included. The rates of association between AS and the well-characterized conditions included: Pseudoxanthoma elasticum (PXE)-228 patients (12.3%), Ehlers-Danlos syndrome-18 patients (1.0%), Paget's disease-6 patients (0.3%), hemoglobinopathies-30 patients (1.6%), and idiopathic-1573 patients (84.9%). There was a statistically higher prevalence of the following less classically associated diseases among patients with AS compared to controls: hereditary spherocytosis (1.7% vs. 0.6%, p < 0.001), connective tissue disease (1.0% vs 0.3%, p < 0.001) and non-exudative age-related macular degeneration (33.9% vs 10.6%, p < 0.001). Among 1442 eligible cases analyzed, 427 (29.6%) received at least 1 anti-VEGF injection with 338 (23.4%) patients having the injection after their AS diagnosis. CONCLUSIONS In the largest collection of AS patients to date, the classical teaching of systemic disease associations occur at rates far, far lower than previously reported. The association of AS with other less reported diseases highlights new potential associations and may contribute to the understanding of AS formation.
Collapse
Affiliation(s)
- Jennifer B Nadelmann
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Yafeng Li
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Retina Center, New York Eye and Ear Infirmary of Mount Sinai, 310 East 14th Street, New York, NY, USA
| | - Brendan McGeehan
- Center for Preventive Ophthalmology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Yinxi Yu
- Center for Preventive Ophthalmology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Brian L VanderBeek
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
- Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics & Epidemiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
- Leonard Davis Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
2
|
Idris IM, Yusuf AA, Gwarzo DH, Kurawa MS, Shuaib A, Galadanci AA, Ibrahim H, Borodo AM, Jobbi YD, Danagundi MB, Borodo SB, Mohammed IY, Galadanci NA, Kuliya-Gwarzo A. High Systolic Blood Pressure, Anterior Segment Changes and Visual Impairment Independently Predict Sickle Cell Retinopathy. Hemoglobin 2021; 45:228-233. [PMID: 34353203 DOI: 10.1080/03630269.2021.1957927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Sickle cell disease is often complicated by retinopathy, which can be proliferative or non proliferative. Proliferative sickle cell retinopathy potentially leads to blindness. There is a paucity of data on sickle cell disease-related retinopathy from Africa, where the disease is most prevalent. We aimed to determine the clinical, ophthalmic, and laboratory predictors of sickle cell retinopathy in an African population. We conducted a cross-sectional study of 262 participants, aged 13 years and above, with sickle cell disease. Demographic and clinical data were collected using a structured questionnaire and standard physical examinations. Vitreo-retinal specialists performed eye examinations on all the participants. Hematological and biochemical assessments were conducted using standard methods. A multivariate stepwise forward logistic regression was performed to determine the predictors of retinopathy. The median age of the participants was 20 years (interquartile range: 17-25 years). Most of the participants had a homozygous Hb S (HBB: c.20A>T) genotype (96.9%), with 3.1% who carried a Hb S/Hb C (HBB: c.19G>A) genotype. The prevalence of non proliferative sickle cell retinopathy was 24.4%. Only 1.9% had proliferative sickle cell retinopathy (PSCR). Elevated systolic blood pressure (BP) [odds ratio (OR): 6.85, 95% confidence interval (95% CI): 1.05-44.45, p = 0.059], moderate visual impairment (OR: 5.2, 95% CI: 1.39-19.63, p = 0.015), and anterior segment changes (OR: 2.21, 95% CI: 1.19-4.13, p = 0.012) were independently predictive of retinopathy. This study provides new insight into predictors of retinopathy in sickle cell disease, with implications on early screening and prevention.
Collapse
Affiliation(s)
- Ibrahim M Idris
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Aminu A Yusuf
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria.,College of Health Sciences, Bayero University Kano, Kano, Nigeria
| | - Dalha H Gwarzo
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria.,College of Health Sciences, Bayero University Kano, Kano, Nigeria
| | - Musbahu S Kurawa
- College of Health Sciences, Bayero University Kano, Kano, Nigeria.,Department of Ophthalmology, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Abdulsalam Shuaib
- College of Health Sciences, Bayero University Kano, Kano, Nigeria.,Department of Ophthalmology, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Aisha A Galadanci
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria.,College of Health Sciences, Bayero University Kano, Kano, Nigeria
| | - Hauwa Ibrahim
- Department of Hematology, Murtala Mohammed Specialist Hospital, Kano, Nigeria
| | - Awwal M Borodo
- Department of Hematology, Murtala Mohammed Specialist Hospital, Kano, Nigeria
| | - Yusuf D Jobbi
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Maryam B Danagundi
- Department of Ophthalmology, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Sakinatu B Borodo
- Department of Ophthalmology, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Idris Y Mohammed
- College of Health Sciences, Bayero University Kano, Kano, Nigeria.,Department of Chemical Pathology, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Najibah A Galadanci
- Department of Epidemiology, University of Alabama at Birmingham, School of Public Health, Birmingham, AL, USA
| | - Aisha Kuliya-Gwarzo
- Department of Hematology and Blood Transfusion, Aminu Kano Teaching Hospital, Kano, Nigeria.,College of Health Sciences, Bayero University Kano, Kano, Nigeria
| |
Collapse
|
3
|
Moussa O, Chen RWS. Hemoglobinopathies: ocular manifestations in children and adolescents. Ther Adv Ophthalmol 2021; 13:25158414211022882. [PMID: 34263135 PMCID: PMC8252354 DOI: 10.1177/25158414211022882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/18/2021] [Indexed: 11/16/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Omar Moussa
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, New York, NY, USA
| | - Royce W S Chen
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, New York-Presbyterian Hospital, 635 W. 165th St., New York, NY 10032, USA
| |
Collapse
|
4
|
Abstract
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.
Collapse
|
5
|
Abstract
PURPOSE OF REVIEW To review recent literature pertaining to sickle cell retinopathy (SCR) and, in particular, sickle cell maculopathy. RECENT FINDINGS Several recent studies suggest that macular perfusion abnormalities seen in patients with sickle cell disease of various genotypes may affect both the superficial and deep capillary plexi, with a predilection for the deep capillary plexus. Further, these changes may be associated with areas of macular thinning, as well as with peripheral retinal ischemia, even in individuals without visual symptoms, contrary to what has previously been described in both diabetic retinopathy and retinal vein occlusion. Several cases also suggest that paracentral acute middle maculopathy may be the pathophysiologic mechanism by which microvascular occlusion leads to macular thinning. SUMMARY Sickle cell disease can manifest in a number of ways within the orbit as well as intraocularly because of its nonspecific vasoocclusive episodes. However, SCR is the most common ophthalmic manifestation of this disease. Historically, SCR has been considered a peripheral retinopathy, but the development and use of spectral-domain optical coherence tomography and optical coherence tomography angiography suggest that significant macular vascular changes occur early in this disease, even in asymptomatic individuals.
Collapse
|
6
|
Oltra EZ, Chow CC, Wubben T, Lim JI, Chau FY, Moss HE. Cross-Sectional Analysis of Neurocognitive Function, Retinopathy, and Retinal Thinning by Spectral-Domain Optical Coherence Tomography in Sickle Cell Patients. Middle East Afr J Ophthalmol 2016; 23:79-83. [PMID: 26957844 PMCID: PMC4759909 DOI: 10.4103/0974-9233.150632] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose: The purpose was to examine the relationship between neurocognitive function and two distinct forms of retinopathy in sickle cell disease. Materials and Methods: Patients with sickle cell disease (n = 44, age range: 19-56 years, 70% female) were prospectively recruited for this cross-sectional study. Retinopathy was characterized by: (1) Presence of focal retinal thinning on spectral domain optical coherence tomography and (2) determination of the sickle retinopathy stage on funduscopic exam based on Goldberg classification. Neurocognitive function was assessed using the Philadelphia Brief Assessment of Cognition (PBAC), a validated test of cognition. Univariate and multivariate analyses for PBAC score outcomes were performed. Retinal thinning and retinopathy stage were primary variables of interest and age, gender, genotype, education, and history of stroke were covariates. Results: Univariate analysis revealed associations with total PBAC score and age (P = 0.049), history of stroke (P = 0.04), and genotype (P < 0.001). Focal retinal thinning and Goldberg retinopathy stage were not associated with each other in this sample. Neither the presence of focal retinal thinning nor degree of retinopathy was associated with total PBAC score in univariate or multivariate analyses. Conclusions: We find an association between lower cognitive function and older age, history of stroke and sickle cell genotype SS in patients with sickle cell disease. Our data do not provide evidence to support an association between cognitive function and retinopathy in sickle cell patients.
Collapse
Affiliation(s)
- Erica Z Oltra
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA; Department of Ophthalmology, Weill Cornell Medical College, New York, NY, USA
| | - Clement C Chow
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA; Retinal Diagnostic Center, Campbell, CA, USA
| | - Thomas Wubben
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Jennifer I Lim
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Felix Y Chau
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Heather E Moss
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
7
|
Risk Factors for Visual Impairment in Patients with Sickle Cell Disease in London. Eur J Ophthalmol 2016; 26:431-5. [DOI: 10.5301/ejo.5000767] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2016] [Indexed: 11/20/2022]
Abstract
Purpose Dramatically improved health care in recent years has increased the life expectancy of patients with sickle cell disease (SCD) as well as the prognosis for its ocular complications. We sought to identify risk factors for visual impairment in patients with SCD in London 4 decades after Goldberg's seminal studies. Methods Patients 16 years and older with SCD (genotypes HbSS, HbSC, HbSβ-thalassemia) attending hematology and ophthalmology services were offered ocular examination. Retinopathy was graded according to the Goldberg classification. Visual impairment was defined as corrected distance visual acuity of 20/40 or poorer. Results In total, 182 eyes of 182 patients (mean ± SD age, 37.2 ± 12.8 years; female, 65.9%) were included. Women were significantly older than men (mean ± SD age, 38.8 ± 13.1 vs 34.2 ± 11.8 years; p = 0.0174). There was no difference in mean age of each genotype group (p>0.15). Risk factors for sight-threatening proliferative sickle retinopathy (PSR) were age over 35 years (odds ratio [OR] 2.01; 95% confidence interval [CI] 1.05-3.89; p = 0.0359) and HbSC genotype (OR 4.06; 95% CI 2.07-7.98; p<0.0001). Although visual impairment was related to the presence of sight-threatening PSR (OR 7.23; 95% CI 1.50-35.0; p = 0.0138), it was not related to hemoglobin genotype (p>0.50). Conclusions We present the largest study of ocular findings in SCD in the United Kingdom. Sight-threatening PSR is a risk factor for visual impairment, but hemoglobin genotype status is not.
Collapse
|
8
|
Fadugbagbe AO, Gurgel RQ, Mendonça CQ, Cipolotti R, dos Santos AM, Cuevas LE. Ocular manifestations of sickle cell disease. ACTA ACUST UNITED AC 2013; 30:19-26. [DOI: 10.1179/146532810x12637745451870] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
9
|
Ocular Manifestations of Sickle Cell Disease at the Korlebu Hospital, Accra, Ghana. Eur J Ophthalmol 2010; 21:484-9. [DOI: 10.5301/ejo.2010.5977] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2010] [Indexed: 11/20/2022]
Abstract
Purpose TO determine the magnitude and pattern of ocular manifestations in sickle cell disease at Korlebu Hospital, Accra, Ghana. Methods Hospital-based cross-sectional study including all patients with sickle cell disease reporting for routine follow-up at the Sickle Cell Clinic at Korlebu Hospital, Accra, Ghana. Results A total of 201 patients with sickle cell disease (67 male and 134 female) were enrolled, comprising 114 subjects with genotype HbSS, aged 6–58 years, mean 19.26 (SD 11.70), and 87 with genotype HbSC, aged 6–65 years, mean 31.4 (SD 16.76). Visual impairment was found in 5.6% of eyes examined. Causes were cataract, proliferative sickle retinopathy (PSR), optic atrophy, phthisis bulbi, and central retinal artery occlusion. Common anterior segment signs of sickle cell disease, which were more common in HbSC patients, were tortuous corkscrew conjunctival vessels, iris atrophy, and cataract. Eyes with iris atrophy or depigmentation were 1.8 times more at risk of PSR than eyes without. Overall, PSR was found in 12.9% of subjects examined (3.5% of HbSS, 25.3% of HbSC; 15.9% of males and 11.2% of females). The prevalence of proliferative sickle retinopathy increased with age and increased systemic severity of sickle cell disease; sex did not have an influence. Conclusions There is a high prevalence of ocular morbidity in sickle cell disease patients at Korlebu Hospital. Prevalence increased with age, systemic severity of sickle cell disease, and HbSC genotype.
Collapse
|
10
|
Tran THC, Mekinian A, Godinaud M, Rose C. [Screening for sickle cell disease retinopathy in the north of France]. J Fr Ophtalmol 2009; 31:987-92. [PMID: 19107075 DOI: 10.1016/s0181-5512(08)74745-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
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.
Collapse
Affiliation(s)
- T H C Tran
- Service d'Ophtalmologie, Hôpital Saint Vincent de Paul, Lille, France.
| | | | | | | |
Collapse
|
11
|
Diallo J, Kuhn D, Haymann-Gawrilow P, Soubrane G. Apport de l’angiographie au vert d’indocyanine dans la rétinopathie drépanocytaire. J Fr Ophtalmol 2009; 32:430-5. [DOI: 10.1016/j.jfo.2009.04.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 04/15/2009] [Indexed: 11/28/2022]
|
12
|
Abstract
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.
Collapse
|
13
|
McLeod DS, Merges C, Fukushima A, Goldberg MF, Lutty GA. Histopathologic features of neovascularization in sickle cell retinopathy. Am J Ophthalmol 1997; 124:455-72. [PMID: 9323937 DOI: 10.1016/s0002-9394(14)70862-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To examine the histopathologic and morphometric features of neovascular lesions in human proliferative sickle cell retinopathy. METHODS Postmortem ocular tissue was obtained from three subjects (aged 20, 28, and 40 years) with SS hemoglobinopathy and prepared for adenosine diphosphatase flat-embedding. Morphometric analysis was performed before serial sectioning. RESULTS Numerous active and autoinfarcted lesions were found that represented virtually all stages in the life cycle of preretinal neovascularization. These formations ranged from single small loops extending from arteries and veins along the retinal surface to the typical complex, elevated sea fan formations. Sea fans developed at hairpin loops and at arteriovenous crossings. There was an average of 5.6 connections between sea fans and retinal vessels; of these, 45% were arteriolar, 52.5% were venular, and 2.6% were at the capillary level. Six of eight sea fans were located at arteriovenous crossings. Autoinfarction appeared to occur initially within the sea fan capillaries. The average height of sea fans was 123 microns above the retinal surface. CONCLUSIONS Preretinal neovascularization in sickle cell retinopathy can arise from both the arterial and venous sides of the retinal vasculature and can assume a variety of morphologic configurations. Multiple feeding arterioles and draining venules are common, and autoinfarction appears to occur initially at the preretinal capillary level rather than at feeding arterioles. Arteriovenous crossings may be a preferential site for sea fan development.
Collapse
Affiliation(s)
- D S McLeod
- Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | | | | | | |
Collapse
|