When treating patients with sickling disorders, hematologists and onco
logists should know those eye lesions that require referral to an opht
halmologist, those that should lead to referral, and those that rarely
are associated with decreased vision. Hyphema in any patient whose re
d cells contain hemoglobin S falls into the first category. Retinal ne
ovascularization (proliferative retinopathy) and its consequence vitre
ous hemorrhage fall into the second. The comma sign, angioid streaks,
and abnormal color vision fall into the third category. The roles of p
reoperative transfusion and experimental antisickling therapy in treat
ment and prevention of eve lesions are incompletely defined at present
.