The purpose of this study is to collect data on patients seen at University of Maryland after undergoing cancer therapy. Previous medications, ocular history, medical history, clinical evaluations, surgical procedures and outcomes will be gathered on the patients who consent to participate. Potential subjects will be enrolled from the clinical practice of the investigator at the time of their eye examination visit. A standard of care exam will be performed pertinent to the reason for the visit. In addition to the standard of care exam, certain biological specimens (ocular surface wash, mucocellular material, corneal filaments, impression cytology, and/or blood) will be collected, stored, and analyzed to obtain immunologic, cellular, or molecular mechanistic insights into disease pathogenesis.

The objective of this study is to evaluate and study the immunologic changes in patients who undergo cancer therapy, specifically identifying patients who are at risk of developing ocular complications from their cancer therapy such as ocular GVHD and corneal toxicity. By creating a detailed registry and robust biobank of patients' samples, the investigators will have the ability to (1) better define the pathogenesis of the ocular toxicity such as ocular GVHD or corneal keratopathy from cancer immunologics, (2) identify predictive factors for developing ocular complications as a result of cancer therapy. By developing a biobank of patients' samples who have undergone cancer therapy, the investigators will have the ability to evaluate clinical findings and determine factors and markers to better understand the mechanisms corneal disease in these patients. Through this biobank, the investigators would like to gather data on the clinical findings and management of ocular complications in patients who have undergone cancer treatment. Participants will fall into one of two groups: either the the Bone Marrow Transplant/Cancer Therapy group or Control group where they have no previous history of cancer therapy. The intervention in this study will be the eye exam.

Inclusion Criteria for the Cancer Therapy Group:

• Adult patients (greater than 18 years of age)
• Deny a history of eye diseases (excluding cataract, glaucoma, mild dry eye disease, or history of cataract or refractive surgery)
• Patients who have a history of allogenic HSCT with all stem cell sources including bone marrow, PBSC, cord AND/OR patients with a history of prior cancer therapy including BMT, chemotherapy, and immunotherapy
• Patients will be recruited after their HSCT or cancer therapy at their ophthalmology appointment
• Patients can be included with a history of prior cancer therapy including chemotherapy, BMT, immunotherapy. Prior cancer therapy must be identified and documented.
• The patient must be able to understand and sign and date the informed consent form approved by the IRB.

Inclusion Criteria for the Control Group:

• No history of cancer or cancer therapy in the past
• Adult patients (greater than 18 years of age)
• Deny a history of eye diseases (excluding cataract, glaucoma, mild dry eye disease, or history of cataract or refractive surgery)
• The patient must be able to understand and sign and date the informed consent form approved by the IRB.

Exclusion Criteria for the Cancer Therapy Group:

• Vulnerable populations: neonates, children, prisoners, institutionalized individuals
• Inability or refusal to provide informed consent.
• History of ocular surgery or ocular disease (except refractive or cataract surgery, mild dry eye disease, or glaucoma).

Exclusion Criteria for the Control Group:

• Vulnerable populations: neonates, children, prisoners, institutionalized individuals
• Inability or refusal to provide informed consent.
• History of ocular surgery or ocular disease (except refractive or cataract surgery, mild dry eye disease, or glaucoma).
• History of cancer or cancer therapy including chemotherapy, immunotherapy, BMT.

Patients who have undergone cancer treatment and in control patients who have not undergone either cancer therapy. The goal of the control patients is to have a direct comparison of 'normal' tear samples as compared to tear/ocular samples from those patients who have undergone cancer treatment.