a 55-year - old male patient developed sudden loss of vision in the right eye following sirsasana with wall support ( 2 minutes ) without supervision . the patient had suffered from pulmonary thromboembolism 5 years back and was receiving warfarin prophylaxis . patient was practicing yoga since past 2 years for 45 minutes , 34 times / week . on examination , best - corrected visual acuity ( bcva ) was finger counting 1 m in the right and 20/20 in the left eye . fundus examination showed disc edema , scattered superficial hemorrhages , and superficial whitening in macular area in the right eye [ fig . 1 ] , whereas the left eye fundus was unremarkable . 2 ] confirmed findings of ischemic crvo with cilioretinal artery occlusion ( red free photos showed retinal whitening along the course of cilioretinal artery in the maculopapillary region and non - filling of the cilioretinal artery in the early phase of angiogram ) all systemic investigations ( hemoglobin , erythrocyte sedimentation rate , lipid profile , blood sugar , serum homocysteine levels ) were normal , and international normalization ratio ( inr ) was 2.0 . over 6 months follow - up , the patient developed neovascularization of the iris and received pan - retinal laser photocoagulation with no improvement in vision . red - free photograph showing disc edema , scattered superficial hemorrhages and superficial whitening in the macular area in the right eye fundus fluorescein angiography photo : venous phase shows altered vascular caliber , blocked fluorescence at the disc due to hemorrhages , and macular ischemia this is an advanced pose and should be attempted after practicing forward and backward bends ( asanas ) , under the supervision of a qualified yoga instructor . sirsasana is known to cause elevation of iop , which reverts to normal after cessation of the same.[2 ] a sudden variation in iop has decompression effect on the eye , as after antiglaucoma surgery , causing decompression retinopathy . the practice of sirsasana is reported to increase the flow of blood to the brain , improving memory and other intellectual functions . although , increased sympathetic vasomotor and sudomotor tone is known to occur after sirsasana , its effect on ocular hemodynamics has not been studied . instructors suggest avoiding sirsasana in patients with hypertension , congestive heart failure , berry aneurysms , and those above 50 years of age . however , there is no existing study to support the above . inr was established by the world health organization ( who ) and the international committee on thrombosis and hemostasis for reporting the results of blood coagulation ( clotting ) tests . a person taking warfarin might optimally maintain a prothrombin time of 2 - 3 inr . this international standardization permits the patient receiving warfarin to travel and still obtain comparable test results . it is known that patients receiving warfarin prophylaxis may not to be protected against a crvo , as in our patient ( inr-2 ) . hence , both the above , in a case of pulmonary embolism , would have predisposed our patient to crvo . we conclude that predisposed subjects such as those having a previous thromboembolic phenomenon and age above 50 years ( as in our patient ) can be warned against doing sirsasana or head down postures in yoga . because of the increased popularity of yoga , a long - term study to know its impact on ocular hemodynamics is needed .
we report a case of central retinal vein occlusion ( crvo ) following sirsasana , a head - down postural yoga . a 55-year - old male patient presented to us , with sudden - onset loss of vision following sirsasana , in the right eye . 
 the patient had suffered from pulmonary thromboembolism 5 years earlier and was receiving warfarin prophylaxis . over 6 months of follow - up , 
 the patient developed neovascularization of the iris and was subjected to panretinal laser with no improvement in visual acuity . 
 sirsasana could be an important risk factor for crvo especially in predisposed patients .