Telemedicine using a macro lens for anterior segment imaging in rural Panama

Abstract

Purpose : Inexpensive tools are necessary to improve eye health of residents in rural areas and developing countries, where eye care is often difficult to access. Our study aimed to determine if a $5 macro lens attached to a smartphone camera is an effective anterior segment imaging method for screening diseases in a low resource setting.

Methods : We conducted a prospective study in Bocas del Toro, Panama, in clinics set up by the medical nonprofit Floating Doctors. Adult patients presenting with ocular complaints had anterior segment photos obtained of each eye using a smartphone with a macro lens attached and a smartphone alone to determine any added benefit of using the macro lens. Images were graded by two board-certified ophthalmologists using a modified version of the FOTO-ED scale. The scale is used to grade images based on overall diagnostic utility and the ability to visualize individual eye components. Statistical analysis was performed using a Wilcoxon signed-rank test to compare the grades between the images obtained by the macro lens versus the smartphone alone.

Results : Fifty-five patients provided a total of 220 images. Table 1 lists the results of the Wilcoxon signed-rank tests using the grades from the FOTO-ED scale. The macro lens demonstrated significantly higher (p<.05) median grades for anterior chamber, iris, lens, while the smartphone had significantly higher (p<.05) median grades for conjunctiva and lids. Anterior chambers imaged with the macro lens were more likely to be characterized as deep (53-74%) relative to smartphone imaging (0-56%). Crystalline lens imaged using the macro lens produced fewer ungradable images (9-17%) compared to the smartphone (34-38%). For all other eye segments and findings, there was no statistical significance to suggest that the macro lens was preferable over the smartphone. 27 patients were marked by the ophthalmologists for follow-up.

Conclusions : Whether the macro lens or the smartphone presented the best quality imaging depended on the section of the eye being examined. An inexpensive lens attachment can allow local staff to take high quality pictures for evaluation via telemedicine as part of an efficient screening eye exam in a low resource setting. In the absence of trained eye care providers, screening for disease by untrained photographers yields appropriate referrals.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Table 1

 

The same eye imaged with a smartphone alone (L) and a smartphone with macro lens (R).