The Jaeb Center for Health Research (JCHR or JAEB) identified shortcomings of traditional chart-based visual acuity assessment techniques:

• The strong dependency on individual proctor skills to achieve valid visual acuity results. 
• Variability of visual acuity results due to manual administration of protocol.
• Variability of visual acuity results due to manual data scoring/handling.

EVA was created around the baseline concept of presenting optotypes via an electronic display. At the time of EVA’s initial conception, displaying optotypes electronically had been previously explored with devices like the Baylor Visual Acuity Tester. However, automation of vision testing protocols, and automation of data handling were the additional core design characteristics that would uniquely define what would be the first version of EVA.

Through rigorous testing and multiple validation studies referenced below, EVA is shown to be a valid alternative to traditional visual acuity testing while providing modern enhancements to user-interface and data handling in an affordable and compact format.

EVA Validation Studies:
"Computerized Method of Visual Acuity Testing: Adaptation of the Amblyopia Treatment Study Visual Acuity Testing Protocol"; Am J Ophthalmol 2001;132:903–909

"Reliability of the Electronic Early Treatment Diabetic Retinopathy Study Testing Protocol in Children 7 to 13 Years Old"; Am J Ophthalmol 2003;136:655–661

"A Computerized Method of Visual Acuity Testing: Adaptation of the Early Treatment of Diabetic Retinopathy Study Testing Protocol"; Am J Ophthalmol 2003;135:194–205