This study is designed to investigate the effect of body posture (particularly when sleeping) on the pressure in the eye. The effect of body posture on progressive glaucoma (glaucoma where a significant change i.e. a disc hemorrhage has occurred) is not known.

The study will involve being admitted to the Sleep Unit of the University Health Network at Toronto Western Hospital for 1 night (14 hours). IOP will be measured in both eyes every 2 hours with a Tonopen, along with brachial blood pressure (BP), in the sitting position until the patients reach their normal sleep cycle time. Patients will then be asked to sleep in either lying down or reclining at a 30 degrees position and have the IOP measurements and brachial BP every 2 hours in that position.

The same cohort of patients will then be invited for a repeat 14 hour IOP and BP measurement but will change their position, i.e. sitting before will now be supine and vice versa.

Inclusion Criteria:

• This pilot study included patients with progressive NTG or POAG as evidenced by disc hemorrhage despite well controlled Intraocular pressures (IOP), who were able to sleep flat

Exclusion Criteria:

• Any patients who were not able to sign a consent or lying flat during sleep