OCT Scanning

Northern Eye Surgeons uses the state-of-the-art spectral domain Zeiss Cirrus OCT Scanner. 

This is a fast very high resolution camera which enables us to:

As an ophthalmic retinal specialist, Dr Johnson delivers presentations to optometrists and ophthalmologists about the use and interpretation of OCT scans.

What is an OCT scan?

OCT stands for Optical Coherence Tomography. It is a specialised camera for taking very high resolution cross-sectional images of the back of the eye. It does this by projecting infra-red light rays into the back of the eye. Those light rays are reflected back from the retina or optic nerve and a computer analyses these results and produces very high resolution images that other cameras cannot produce.

When is it useful?

Whilst most retinal diseases are obvious on clinical examination, some diseases can be difficult to detect and in that instance OCT scans can be useful. OCT scanning is also essential for treating the most common cause of blindness in Australia, wet macular degeneration.

For chronic, slowly progressive diseases (such as glaucoma), OCT scanning can help detect change earlier.

What does a normal OCT of the macula look like?

This is an OCT of a normal macula. The depression in the middle of the picture is called the foveola. This accounts for the most central part of your vision.

What does an OCT of dry macular degeneration look like?

This is an OCT of dry macular degeneration. There are drusen, underneath the retina (the grey 'lumps' visible at the bottom of the picture). Drusen are accumulations of waste product, that can damage the macula resulting in loss of vision. For more information about dry macular degeneration, please click here.


What does an OCT of wet macular degeneration look like?

In this OCT of wet macular degeneration, there is a pigment epithelial detachment (the large bubble at the bottom-left of the retina) associated with some sub-retinal fluid. Leakage of fluid is the hall-mark of wet macular degeneration, and indicates an abnormal blood vessel grwing underneath the retina. This may result in sudden vision loss through haemorrhage, or the formation of scar tissue. For more information about wet macular degeneration, please click here.


What does an OCT of central serous retinopathy (CSR) look like?

This is a typical OCT of CSR. Subretinal fluid has elevated the retina causing a 'grey patch' in the center of this patients' vision. For more information about CSR, please click here.


What does an OCT of diabetic maculopathy look like?

Maculopathy is a common cause of vision loss in patients with diabetes. The OCT at the top, shows swelling of the macula in a diabetic, which is lessened following treatment with intravitreal avastin (bottom OCT). For more information about diabetic maculopathy, please click here.


What does an OCT of a branch retinal vein occlusion (BRVO) or central retinal vein (CRVO) look like?

Retinal vein occlusion is a common cause of vision loss. The OCT shown above is in a patient with a central retinal vein occlusion. It demonstrates retinal thickening due to intra-retinal oedema, with a very small amount of subretinal fluid.  For more information about retinal vein occlusions, please click here.


How does an OCT help monitor the progression of glaucoma?

Glaucoma is a disease where the optic nerve becomes progressively damaged - usually due to high pressure inside the eye. Since the OCT is able to take very high resolution images of the optic nerve head, it is possible to detect a worsening of the disease earlier than would otherwise be possible.

However, the OCT test does need to be interpreted properly, and in conjunction with many other factors, such as the intraocular pressure, visual fields and a detailed clinical examination.

Dr Joshua Yuen

Dr Joshua is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more

Dr Brad Johnson

Dr Johnson is an experienced consultant ophthalmic surgeon, who specialises in retinal diseases and cataract surgery... read more