instruction: give me the number of patients whose diagnoses short title is ventricular shunt status and drug route is left eye?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE diagnoses.short_title = "Ventricular shunt status" AND prescriptions.route = "LEFT EYE"