Optical Coherence Tomography
The first optometry practice in the UK to use Opticical Coherence Tomography
In 2005 Barnard Levit optometrists became the first in the UK to incorporate the OCT into primary care practice. This instrument provides a non-invasive, non-contact, micron resolution analysis of eye tissues. It enables real-time in situ imaging of tissue structure or pathology with a resolution of 5 microns. This instrument enables us to carry out a non invasive “biopsy” of the retina, macula and optic nerve and obtain a 3-D analysis. The technique is comfortable and quick. In February 2017 we upgraded to the latest Zeiss Cirrus 5000. The OCT is used to assess a wide range of eye conditions. Here are some of the more common ones:
Early glaucoma detection and monitoring
It is estimated that 50% of patients with glaucoma in the UK are undiagnosed and up to about half of all patients with glaucoma have “normal” eye pressures. OCT enables us to study in detail the structure of the optic nerve and assist detection of the most subtle changes due to glaucoma. Whilst it does not replace conventional optic nerve examination, visual field testing and the measurement of eye pressure it helps us detect glaucoma as early as possible. OCT is suggested for patients with a risk of developing glaucoma (such as a family member with glaucoma) and when other signs detected by your optometrist.
Macular degeneration and macular holes
Age related macular degeneration (AMD) is the commonest cause of poor vision and blindness in the UK. Early detection is a challenge because most of us show age related changes as we get older. These early, “dry” macular changes are insidious and increase the risk of the patient developing the more serious type of AMD, the “wet type”. The latter occurs due to fine blood vessels growing deep in macula of the retina. These vessels are fragile and can leak, hence the name “wet”. OCT assessment of the macular will assist us in monitoring the “dry” changes and detecting new vessel growth at an earlier stage. It also allows us to differentially diagnose macular holes and pseudo-holes.
The image below shows a Zeiss Cirrus OCT scan of a normal macula.
Diabetic patients are prone to leaks of blood and plasma within the retina. One of the more difficult diabetic changes to detect is oedema (or swelling) of the macula because its appearance is very subtle. OCT enables us to measure very accurately the thickness of the macula to help detect early changes. OCT compliments the Optos Daytona wide field imaging system and conventional indirect ophthalmoscopy that we use routinely on all patients to view their retina.