This study aims to investigate the effects of topical cyclosporin A on dry eye. A total of 30 patients will be selected from among those referred to the Ophthalmology Clinic of Vali-Asr Hospital in Birjand. The participants should be suffering from clinical and paraclinical symptoms of dry eye and be willing to participate in the study. Selection will be through purposive sampling method, and the study is single-blinded, one-centered, and in the third phase of clinical trial. The right eyes of the participants are considered as the case group and their left eyes, as the control group. One drop of cyclosporin A eye drop will be used for the right eye every 12 hours, and one drop of artificial tear eye drop will be applied every 12 hours for both eyes. The treatment will continue for 3 months. The subjective symptoms, as the primary outcomes of the study, will be examined in terms of duration, frequency, and severity on the first visiting session, one week, one month, and three months later. The signs include feeling eye dryness, feeling of sand in the eyes, itching, pain and burning eyes, watery eye, and eye fatigue.