What is EVA?

Emmes EVA medical devices are the continuation of the original Electronic Visual Acuity (EVA) devices developed by the Jaeb Center for Health Research (JCHR or JAEB).  Emmes EVA devices are robust, semi-automated visual acuity assessment platforms designed to replace traditional eye charts and manually-proctored visual acuity protocols, such as ETDRS.

Emmes EVA devices feature compact size, intuitive operation, and structured electronic data management.  Emmes EVA devices pair well with clinical research, or can serve as supplementary in-clinic visual acuity assessment tool for clinicians.

What are the advantages of Emmes EVA to chart-based protocols?

Electronic, Semi-Automated

Lower demand on the proctor; the test and test results are less impacted by human factors.

Compact Size

3-meter visual acuity assessment lane as opposed to 4-meter required by chart-based protocols like ETDRS.


Modern and wireless proctor control via a hand-held touch screen interface.


Secure and organized data handling methods, including database encryption and structured reporting from the study level to the assessment level.

Why Emmes EVA?


  • Visual acuity assessment is a cornerstone for many ophthalmic trials and clinical triage assessment, for both safety and primary outcome.
  • The reliability, repeatability, and accessibility of visual acuity assessment is of paramount importance in both research and clinical industries.
  • Emmes EVA solves real-world problems.

The Problem of Human Error:  Chart-based visual acuity assessment inherently has limitations with respect to reliability and repeatibility of test results due to naturally-occuring human error.

Emmes EVA Solution:  Emmes EVA devices address and improve upon reliability and repeatability by minizing the impact of human-induced error and data noise.

The Problem of Inadequate Space:  Chart-based visual acuity assessment protocols such as ETDRS require a 4-meter assessment distance making it difficult for soem clinics and facilities to accomodate.

Emmes EVA Solution:  Emmes EVA improves upon accessibility by reducing the required assessment distance to 3 meters.