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Cup-to-disc ratio measured with mobile device correlates with OCT
Researchers found a strong correlation between vertical cup-to-disc ratios obtained with an electronic mobile device and spectral domain OCT.
The use of this low-cost mobile system could potentially increase access to care among low-income populations and those in remote areas, the authors said.
Sarmento and colleagues performed a single-masked study involving 110 eyes of 110 subjects between 18 and 60 years old. Vertical cup-to-disc ratio (CDR) was measured five times with the electronic mobile device (EMD) and spectral domain OCT by three different ophthalmologists.
The EMD was a PanOptic 11820 Ophthalmoscope (Welch Allyn) combined with a portable TRDM-D5M camera (Terasic) and storage device, according to the study. This model is currently being adapted for use with a smartphone to further decrease costs, authors noted.
The mean values for the vertical CDR were 0.34 ± 0.27 for clinical evaluation, 0.47 ± 0.04 with SD-OCT and 0.42 ± 0.02 with the EMD, all of which were considered to be strongly correlated to each other.
The researchers noted that this work did not involve patients with glaucoma, but that a future study would.
In their conclusion, the authors commented on the potential use of this device in telemedicine: “The EMD may be useful in glaucoma screening programs, particularly in remote areas where access to expensive devices and specialists is more limited.” – by Nancy Hemphill, ELS, FAAO
Disclosures: The authors reported no relevant financial disclosures.
Perspective
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A low-cost portable device that can measure CDR (potentially) as accurately as OCT is an interesting technological achievement. Its utility in telemedicine and access to care for developing nations and remote communities could be extraordinary. That being said, a CDR approximation is a screening tool and does not replace IOP, pachymetry, gonioscopy or retinal nerve fiber analysis, which is the primary advantage of OCT. It should be made very clear that this is not a substitute for OCT or dilated examination.
However, it does raise the possibility that a portable system could be created that rivals OCT technology at a fraction of the cost. Technology is rapidly evolving, and there’s a risk of obsolescence – of the sort we’ve seen with scanning laser polarimetry. This could have consequences for practices that invest in currently available hardware.
For example, the emerging importance of the ganglion cell has the potential to make some current OCT units outdated. It is important to not become paralyzed with fear and embrace progressive technology. Ultimately, it seems like an unavoidable cost of doing business to take the leap and purchase current imaging systems hoping they will pay for themselves in terms of patients served and dollars spent.