In another thread on OD Wire, there have been some questions and comments on which OCT brand is best for glaucoma management.
Although I (of course!) won't be promoting any particular brands, my CE Wire presentation will explain some of the fundamental features of OCT instruments, and which hardware and software features are recommended or even essential for optimal glaucoma clinical management.
Without having to study electrical engineering, hardware features like laser wavelength, scan speed, sensor capture resolution and gaze tracking all matter a lot. Fundus imaging modality such as flying spot scanning laser ophthalmoscope works better than line scanning laser ophthalmoscope and both are much better than the useless color fundus photograph.
Software features such as the scan types offered are very important. For example a macular GCC scan is much more useful when it is a 9 x 9 mm cube measuring all 3 components of the ganglion cell right up to the disc itself, rather than a 4.8 x 4.0 mm oval that doesn't get close to the disc and only measures part of the ganglion cell thickness components. Or how an RNFL disc circle scan is more precise and repeatable than a disc cube scan and therefore much better for progression analysis.
A lot of practitioners worry about the size of the normative database, but in practice it is much less critical than the correct scan type that is precise and repeatable and analysed by accurate progression analysis software. And what about being the "Gold Standard"? You become gold standard by being used in a lot of published papers and clinical trials, but what if most of the NIH/NEI research dollars are in the USA, but a better glaucoma instrument than the "Gold Standard" is not even sold in the US?
OCT manufacturers balance all these factors when developing an instrument. Some favour one-touch ease of use, others try to sell at the lowest price, some like to incorporate colour photos because you can't bill both OCT and photos at the same visit. And others try to produce the best OCT for glaucoma management. Even within one instrument manufacturer's range there can be a big difference in features and components, in the same way a Mercedes C180 looks like a C63 AMG but performs very differently. A Nidek Retina Scan Duo is much worse for glaucoma than the Nidek RS-3000 or RS-1. The Zeiss Cirrus 500 is much worse than the Cirrus 5000 or 6000 series.
For run-of-the-mill eye exams, these issues do not matter much and any OCT will do. But for the best possible glaucoma management they are critical, otherwise you will be making the wrong treatment decisions based on faulty data.
