chemical warfare agents ( cwa ) such as sulfur mustard ( sm ) , a vesicant agent , were extensively used against the iranian troops and civilians during 1983 - 1988 .
other proliferating stem cells may also involve and induce long - term impairments , including respiratory and ocular complications .
central retinal vein occlusion ( crvo ) is a relatively common retinal vascular disorder and a frequent cause of visual morbidity in patients older than 50 years and can be associated with systemic vascular disease and coagulopathy .
although most patients with crvo are over 65 years , it can occur in younger patients commonly termed papillophlebitis .
younger patients frequently have an associated inflammatory cause or coagulopathy , which deserve particular attention . up to now ,
as far as we are aware , no early or late retinal complication of sm exposure has been reported . here ,
we report a fairly young man presented with non - ischemic crvo without any systemic known predisposing factor except for a history of sm exposure .
a 41-year - old man was referred to our eye hospital with a complaint of sudden visual loss in his left eye .
an eye examination showed that his best corrected visual acuity ( bcva ) in the right eye ( re ) was 20/20 and in the left eye ( le ) was 20/80 .
relative afferent pupillary defect ( rapd ) was slightly positive in the left eye as sluggish movement of the iris .
intraocular pressure ( iop ) was 13 and 15 mmhg in re and le , respectively .
tear break - up time was less than five seconds , which indicated an abnormal tear film .
funduscopic examination of his right eye showed no specific abnormality . in the left eye , retinal hemorrhage in all quadrants of the retina ,
retinal edema , venous tortuosity , and macular edema were present ( figure 1 ) .
in fluorescein angiography delayed circulation , hyperfluorescence due to the breakdown of the blood - retinal barrier , venous tortuosity , and blockage due to retinal hemorrhages were obvious ( figure 2 ) .
in ocular optical coherence tomography ( oct ) , macular edema was obvious and central macular thickness was increased to 357 microns ( figure 3 ) .
. shows fundus photo of the patient who was exposed to sulfur mustard showing vascular tortuosity , hemorrhages , and macular edema .
fluorescein angiography showing vascular tortuosity , macular edema , hemorrhages , multiple hypo and hyperfluorescence of the fundus in a 41-year - old male patient who was exposed to sulfur mustard .
optical coherent tomography ( oct ) of the macula showing macular edema in a 41-year - old male patient who was exposed to sulfur mustard .
hiv ( eliza ) , antinuclear antibody ( ana ) , and rheumatoid factor ( rf ) tests were also negative .
all biochemical , immunological and hematologic investigations revealed no abnormalities and the results are summarized in tables 1 and 2 .
results of the biochemical and immunological investigations results of the hematologic investigations the patient had no history of systemic arterial hypertension , no obvious cardiac disease , and no connective tissue diseases . however , cardiology and rheumatology consultations were requested .
echocardiographies , both trans - thoracic and trans - esophageal , were negative for structural cardiac abnormalities .
although all routine coagulation laboratory tests were within normal limits , we also requested hematologic consultation to rule out any coagulopathies .
after 15 months , the consultations were repeated and again all were reported as normal .
again , we reviewed his possible use of any drug , medication ( either chemical or herbal ) trauma , smoking , and familial history of such diseases .
however , the patient had three times exposure to sm during 1987 - 1988 iran - iraq war .
he had ambulatory admission and treatment in a field hospital after the last sm exposure in 1988 and recovered within two days .
following written informed consent , he received four serial intravitreal injections of an anti - vascular endothelial growth factor , bevacizumab ( 1.25 mg/0.05 milliliter ) , as an off - label treatment modality .
after one year , the central macular thickness decreased to 334 microns and vision improved to 20/25 .
the patient was followed up for more than 24 months during which he had stable retina and vision .
the patient was informed about the publication of this case report and an oral consent was obtained .
sm and similar bifunctional agents have been produced as chemical weapons since the 19 century .
high dose exposure to sm may result in death within hours or weeks . however , low - dose exposure may cause injury to the eyes , skin , and respiratory tract without any mortality .
very low dose of sm exposure may not induce any symptom or sign and thus it is called subclinical exposure .
it seems that our patient had two subclinical exposures in 1987 and one mild symptomatic sm exposure in 1988 , after which he recovered within a couple of days .
however , long term effects and delayed complications of sm poisoning are well known and several reports are available , particularly on the respiratory tract , skin and the eyes .
. it could be due to ocular characteristics such as high turnover rate , intense metabolic activity of corneal epithelial cells , and the aqueous - mucous surface of the cornea and conjunctiva .
as it is absorbed by the lungs and skin , it may disseminate in the body and act as a toxic agent involving the internal organs as well .
to our knowledge , no retinal abnormal finding ensuing sm exposure has been reported yet .
endothelial cells are proposed to be injured in the sm toxicities and may induce apoptosis and necrosis in endothelial cells all over the body .
this may explain the vascular permeability in acute phase after exposure , which can result in bronchial edema .
long term effect of sm on vessels may predispose them to occlusion , particularly in microvasculature system such as the retina .
crvo is usually associated with systemic cardiovascular diseases and coagulopathies ; and is mostly observed in elderlies .
crvo in young adults is probably a general ( nonspecific ) change that results from a number of individual causes or a combination of causes . in unusual cases ,
the cause is known but in the vast majority of the patients , the specific cause or even the contributing factors are unknown .
this is mainly due to limited literature and the paucity of histopathologic material from patients with such condition . in our case
, we performed a wide array of laboratory tests , systemic work up , and consultations according to the current findings and algorithms .
as all our tests and consultations were normal , we re - evaluated the patient and found a history of exposure to sm , a highly toxic chemical warfare agent that may have caused or played a predisposing factor for his non - ischemic crvo .
we thus propose that sm may cause or act as a predisposing factor for non - ischemic crvo .
 a 41-year - old man was referred with a complaint of visual loss in his left eye and his best corrected visual acuity was 20/80 . 
 slit lamp examination showed arborizing conjunctival vessels and dry eye . 
 fundus examination and fluorescein angiography revealed a non - ischemic central retinal vein occlusion . 
 cardiovascular , rheumatologic , and hematologic work up showed no abnormal findings . 
 an ascertained history of exposure to sulfur mustard during the iran - iraq war was documented in his medical history . 
 four sessions of intravitreal bevacizumab injections were done as needed . 
 after two - year follow - up , visual acuity in his left eye improved to 20/25 and macular edema was resolved without any need for further interventions . 
 we conclude that sulfur mustard gas exposure may be considered as a predisposing factor for central retinal vein occlusion , as was found in our patient ( an iranian war veteran ) by excluding all yet known etiologies and predisposing factors . 
Introduction
Case Report
Discussion