Since the initial description, the therapeutic efficacy of CsA for human KCS has been well documented, with evidence ranging from several small single center randomized double-masked clinical trials to several large multicenter randomized, double-masked clinical trials.(10-12) Therefore, the aim of the work is to evaluate the effect of using topical CsA in treatment of moderate to severe dry eye.

Dry eye disease (DED) is known to be among the most frequently occuring ocular morbidities. It is a growing public health concern affecting 25% of patients who visit ophthalmic clinics.For many years, DED was considered to be limited to dryness of the eyes due to decrease in the aqueous phase in the tear film. In 2007, the International Dry Eye Workshop discussed the definition and classification of DED and developed a new vision for the definition and the three-part classification of DED on the basis of etiology, mechanism, and severity of DED. Moreover, DED can be episodic or chronic. Episodic DED occurs when environmental or visual tasks with reduced blinking overwhelm the stability of the tear and produce symptomatic DED. Chronic DED, although aggravated by the same environmental conditions, persists continuously with symptoms and possible damage to the ocular surface. Because the tear film in DED patients is not stable and incapable to maintain the protective qualities that are important for its structure and function, patients usually experience the discomfort manifestations associated with DED such as burning, stinging, foreign body sensation, ocular fatigue, grittiness, tearing, and dryness. Patients may complain of symptoms of DED in the presence or absence of the known signs and DED may be diagnosed based only on the signs observed by a healthcare professional in the absence of symptoms reported by the patients.Since the initial description, the therapeutic efficacy of CsA for human KCS has been well documented, with evidence ranging from several small single center randomized double-masked clinical trials to several large multicenter randomized, double-masked clinical trials.Therefore, the aim of the work is to evaluate the effect of using topical CsA in treatment of moderate to severe dry eye.

Inclusion Criteria:

• We included all patients with moderate to severe dry eye disease (grade 3 or grade 4) with the following criteria: The tear film break up time ≤5 seconds for grade 3 and immediate for grade 4, schirmer test with anesthetic is ≤5 millimeters for grade 3 and ≤2 millimeters for grade 4, corneal or conjunctival staining pattern with fluorescein is abnormal and consistent with an abnormal tear film. Oxford grade II or more, meibomian gland dysfunction is documented (inspissation of the meibomian gland orifices, pitting and neovascularization of the eyelid margins) and one or more moderate (≥2+) dry eye related symptoms; including itching, burning, blurred vision, foreign body sensation, photophobia, veiling, and soreness or pain

Exclusion Criteria:

• Exclusion criteria included Post LASIK patients, Post radiation fibrosis of lacrimal gland, Vitamin A deficiency, Conjunctival scarring (advanced trachoma, chemical burn, OCP), Drugs (anti-histaminics, anti-cholinergic, anti-psychotics, selective serotonin uptake inhibitors), Patients with familial dysautonomia (Riley-Day syndrome), Use of systemic or topical CsA in the previous 90 days.