Towards the Development and Validation of a Smartphone-Based Pupillometer for Neuro-Ophthalmological Diseases Screening

Pupillometry allows a quantitative measurement of PLR and has been mainly used to assess patient’s consciousness and vision function. The analysis of pupil light reflex (PLR) has been showing a renewed interest since the discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs), that are sensitive to the blue light, as they have an important role in pupil response to a stimulus. Some researches have studied pupillometry, particularly chromatic pupillometry that uses blue and red stimuli, to be a screening tool for neuro-ophthalmological diseases. Automated pupillometers have been widely used, however they are either not portable or expensive, reason why this technique has been mainly used in academic research. A smartphone-based pupillometer could be a promising equipment to overcome these limitations and to be a widespread screening tool, due to its low price, portability and accessibility. This work shows our latest advances towards the development and validation of an Android system for pupillometry measurements. Pupillometric data was collected with the smartphone application in a group of five healthy individuals and used to test our proposed data processing algorithms. These tests showed that the data processing methods that we are proposing, although promising, did not behave as expected, indicating that new approaches, better validations and corrections should be made in the future to get a stable software for pupil detection. Nevertheless, preliminary pupillometric data indicate that this system has the potential to work as an inexpensive, easy-to-use and portable pupillometer.