The investigators propose to collaborate with Singapore General Hospital, Department of Haematology to focus on the clinical characteristics and immunological profile of the ocular surface inflammation in more severe chronic GVHD patients. Dry eye severity is more severe in chronic GVHD patients at SNEC, compared to idiopathic cases of dry eye. This may be due to referral bias, or may be related to the systemic disease. As such, the investigators intend to do a pilot study to define some ocular characteristics of non-referred haematology patients with GVHD. The investigators propose to screen and recruit 30 suitable participants who have chronic GVHD. Tests to be performed will include ocular imaging (Oculus K5M), ocular immunological profile (conjunctiva immune cells) and ocular surface inflammation (MMP-9 tear marker).