Eyes are very sensitive to sulfur mustard (SM) gas because they have wet surfaces. The severity of ocular damage is related to the dose and duration of exposure to SM, and recovery may take up to several years after the exposure. We conducted a large cohort study to evaluate the ocular signs and symptoms of 367 chemical war victims in Sardasht City, Iran, 20 years after their exposure to mustard gas. The results of these chemical war victims (i.e., the cases) were compared with the results for 128 unaffected civilians (i.e., the controls). Photophobia was the most significant symptom in the cases (36.8%) (compared with 20.3% in the controls) (p < or = .001). Ocular surface discomfort (burning, itching, and redness) was the second most significant symptom in the cases (29.2%) (compared with 19.5% in the controls) (p = .034). Other symptoms such as foreign-body sensation, tearing, pain, blurring of vision, and dry eye sensation were not significantly different between the 2 groups. In the slit-lamp findings, bulbar conjunctival abnormality was the most significant sign in the cases (9.3%) (compared with 1.6% in the controls) (p = .004). Limbal tissue changes were the second most significant sign in the cases (3.0%) (compared with 0.0% in the controls) (p = .048). Other slit-lamp findings related to tearing and abnormalities in the lids and cornea were not significantly different between the 2 groups. Our findings in the present study showed that photophobia and ocular surface discomfort (burning, itching, and redness) were the most significant symptoms. In addition, bulbar conjunctival abnormalities and limbal tissue changes were the most significant signs among the sulfur mustard chemical war victims.