Smartphone apps could be used to measure exophthalmos

A smartphone-based tool could be an alternative to the Hertel exophthalmometer in measuring eye protrusion (exophthalmos).

Study design

This was a cross-sectional study of eye protrusion measurements using 3 different methods: the standard Hertel exophthalmometer, a smartphone application, and a 3-dimensional (3-D) scanner. Twenty-three patients with exophthalmos and 16 healthy volunteers were recruited from a single clinic in Switzerland, and all were scanned with each tool.

Outcomes

All of the measurement methods showed high accuracy and precision, inter-operator reliability, and test–retest reliability. No significant differences in eyeball protrusion measurements between the methods were seen.

Limitations

Three separate requirements are needed to use a smartphone to measure protrusion, limiting its use in real-world situations: a specific smartphone (iPhone11), a special application (TrueDepth), and specific software to process the scans taken with TrueDepth (MATLAB software version 2019). It is not known whether TrueDepth will be made for smartphones with different operating systems (e.g., Android).

Clinical significance

As Hertel exophthalmometry requires experience and 3D scanners are expensive and not readily available, a smartphone application may play an important role in measuring eyeball protrusion in telemedicine and non-ophthalmologic arenas. Currently, a smartphone-based measurement is still out of reach for most clinicians; however, once the measurement is simplified to a downloadable program that is readily available and usable with only a smartphone, patients and non-ophthalmologists could potentially track eyeball protrusion to improve earlier detection of problems.

Financial Disclosures: Dr. Anne Barmettler discloses no financial relationships.