Dose-response Study of OPC-12759 Ophthalmic Suspension

Inclusion Criteria:

1. Outpatient.
2. Subjective complaint of dry eye that has been present for minimum 20 months.
3. Primary ocular discomfort severity is moderate to severe.
4. Corneal - conjunctival damage is moderate to severe.
5. Unanesthetized Schirmer's test score of 7mm/5minutes or less.
6. Best corrected visual acuity of 0.2 or better in both eyes.

Exclusion Criteria:

1. Presence of anterior segment disease or disorder other than that associated with keratoconjunctivitis sicca.
2. Anticipated use of any topically-instilled ocular medications or patients with cannot discontinue the use during the study.
3. Anticipated use of contact lens during the study.
4. Any history of ocular surgery within 12 months.
5. Female patients who are pregnant, possibly pregnant or breast feeding;
6. Known hypersensitivity to any component of the study drug or procedural medications.
7. Receipt of any investigational product within 4 months.