As service manager of ophthalmic imaging at Sheffield Teaching Hospitals, I manage a team of 20 ophthalmic professionals who perform over 90,000 procedures a year. Therefore, we require our optical coherence tomography (OCT) scanners to be robust and fairly indestructible.
The first OCT arrived in our department back in 2003 and in the intervening period, technology has changed dramatically. In 2003, we performed 55 scans. However, in the last 12 months we have performed over 35,000, with seven scanners. OCT is by far our most commonly requested test and is used by all specialities within the ophthalmology department.
Our Spectral domain OCTs use near-infrared light at a wavelength of 870nm, allowing high resolution imaging with a scan beam depth range of around 1.8mm. This means that it can be used not only for imaging the retina, but also the vitreous in front and the choroid behind the retina.
Most commonly, we use the system for monitoring and diagnosing patients with age-related macular degeneration, diabetic retinopathy, glaucoma, macular holes, macular retinal detachments, uveitis and trauma cases.
The OCT plays an extremely important role in identifying these types of retinal problems and the OCT will often determine whether further diagnostic testing is required.
“OCT is by far our most commonly requested test and is used by all specialities within the ophthalmology department”
Easy to use
All of our OCTs are very operator friendly. The scanner heads are able to pan and tilt so practitioners can image both the peripheral and the central retina. Operators can also use a 55-degree lens, which will give them a wider 16mm scan of the retina.
Different software and hardware options are available, so you can build the system to suit your individual practice.
In Sheffield, we also use the glaucoma module, which allows us to map the retinal nerve fibre layer, minimum rim width and ganglion cells. This can be compared to a normative database of patients of the same age and ethnicity to show abnormalities. With follow-up patients, we are also able to map and show whether there is any progression of disease.
Adapting a tool for all
A basic scan protocol can be completed within five minutes. However, it is important to carefully check that contour calipers are correctly positioned so the correct information on retinal thickness is given.
Our OCTs are table-based devices. However, we have also recently had a custom designed specialist arm built so that a scanner head can be mounted onto it, making the OCT useable for patients within the operating theatre setting, as well as for patients with mobility issues in clinic who cannot be accommodated at a table-based scanner. This has ensured the important OCT technology is open to all.