Prevalence of Ocular Surface Disease in Malaysian Glaucoma Patients

Inclusion Criteria: * 1\) Age of 21 years or older and those who can provide informed consent. * 2\) On anti-glaucoma medications for \>6 months * 3\) IOP ≤ 21 mm Hg in the study eye at the screening examination (under treatment) * 4\) If only one eye is eligible, it is to be evaluated. If both eyes are eligible, then the eye with a higher NEI score will be selected for evaluation. * 5\) A best-corrected visual acuity score of 6/36 on the Snellen Chart, or better in each eye. Exclusion Criteria: * 1\) Those with secondary ocular hypertension or glaucoma * 2\) Those with severe visual field disorder (mean deviation of 20 dB or worse) * 3\) Those with a history of ocular surgeries (intraocular surgery including ocular laser treatment which may affect the patient's ocular surface condition) within 6 months prior to the study initiation. * 4\) Those with a history of glaucoma surgery * 5\) Those with a history of corneal refractive surgery * 6\) Those with severe dry eye associated with systemic disorders, or in need of drugs to treat dry eye * 7\) Those with ocular allergy, ocular infection or ocular inflammation * 8\) Those using eye drops for other ocular comorbidities * 9\) Those who need to use systemic or ophthalmic steroids (excluding topical skin steroidal ointment) * 10\) Female patients who are pregnant, nursing or lactating * 11\) Those who use contact lenses * 12\) Any corneal abnormality or other corneal comorbidity condition preventing reliable applanation tonometry * 13\) Those on oral antihistamine, antipsychotic or anti-depressant drugs.