September Case #1: Blindness

60 y/o AAM presents to the ED with complaints that he is having difficulty seeing out of his R eye over the past several days.  He states that he has not been able to see out of his left eye for about 10 years and never had this complaint evaluated.  He denies pain, trauma, drainage or headache.
PMHx: HTN
PSHx: none
FamHx: DM, CAD
SocHx: +tob (ippd); no ETOH or IVDU

PE: BP 170/83, P 99, R 16, T 98.6, POx 99% (RA)
GEN:  WNWD AAM, NAD
EYE:  visual accuity 20/100 OD, 20/200 OS;  EOMI;  lids, lashes and lacrimals normal;  no conjunctival injection;  no fluoresceine uptake or dendritic lesions;  no FB or rust ring noted;  anterior chamber flat and narrow, no cell and flare; L pupil irregular and minimally reactive;  IOP 16OD, 20OS;  no seidel's sign;  fundoscopic exam limited

Bedside US performed:

What is the diagnosis?