Glaucoma Investigation and Co-management

Glaucoma is a form of optic neuropathy – in other words a disease affecting the optic nerve. There are a number of types of glaucoma, the most frequently encountered being primary open angle glaucoma. Sometimes but not always, glaucoma may be associated with higher than normal pressure inside the eye.

Risk factors for glaucoma other than higher-than-normal eye pressure include increasing age, a family history of glaucoma, diabetes and thinner-than-normal corneas.  Glaucoma is a progressive disease, and is detected by observing structural changes to the nerve fibres and optic nerve at the back of the eye, as well as functional changes that reduce sensitivity to light and eventually lead to blind spots in parts of the field of vision.

Glaucoma investigation procedures 
The procedures that are conducted to establish your risk of developing or having glaucoma, or to track the progression of existing glaucoma, include:

• Ocular coherence tomography (OCT) disc circle and disc map scans – the disc circle scan meausres the thickness of the retinal nerve fibre layer surrounding the optic disc, whereas the disc map records the topography of the disc.  Both these scans compare your nerve structures to normal values, but more importantly can be used as a baseline and/or compared to other scans taken at different times.
• Automated perimetry, or measurement of the visual fields – this this test requires you look directly at the central light of the perimeter bowl.  Other lights of varying brightness flash, one at a time, anywhere in the central and peripheral fields.  You have a response button to press each time you notice one of those lights flashing.  It normally takes about ten minutes for each eye to take a detailed field measurement.
• Measurement of the intra-ocular pressure (internal pressure of the eye) and thickness of the central cornea.
• Examination of the anterior chamber angle by slit-lamp biomicroscopy and/or gonioscopy.  This may be supplemented by an anterior OCT scan.

Fees for detailed glaucoma investigations
The fee for a detailed glaucoma investigation is made up of the following components:

• Automated perimetry $80.90 – usually you will receive a Medicare rebate of $59.60
• Ocular coherence tomography $80.90 – there is no Medicare rebate for this item
• If you have been referred by another optometrist, a Medicare item 10905 will be bulk billed, so will be at no additional cost to you 

Following your consultation
If you have been referred by another practitioner, a full report including the results of all the procedures will be forwarded on to them.  You will also be advised of the appropriate time to be reviewed again.  If we see enough evidence to indicate that you are already developing glaucoma or are at high risk of doing so, you may be referred to an ophthalmologist who specialises in the management of this disease.  Alternatively if you have glaucoma, a decision may be made to co-manage the condition with an ophthalmologist, where you will generally attend this practice for the clinical investigations, the results of which are then forwarded on to the co-managing ophthalmologist. 

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