US soldiers using Microsoft’s new HoloLens augmented reality (AR) glasses in recent field tests experienced “mission-impacting physical impairments” including headaches, eye strain and nausea, according to a report on test results prepared by the Pentagon Test Office, reports Bloomberg.

More than 80 percent of those who experienced discomfort had symptoms less than three hours after using a special version of Microsoft’s HoloLens glasses, said Nicholas Guertin, director of Operation Test and Evaluation, in a summary for Army and Defense Department officers. According to him, the system still has too many failures in performing basic functions.

Problems found during tests in May and June were outlined in a 79-page report this month. The Army marked it “Controlled Unclassified Information” to prevent public release, but Bloomberg obtained a summary of it.

Despite the shortcomings of the device, Guertin does not consider it a lost cause. He recommended the Army “prioritize improvements” before widespread deployment to reduce “physical discomfort of users.” According to him, the low-light sensors, display clarity, field of view and low reliability of some important functions of the glasses also need improvement.

At the same time, the reliability of the latest model has improved according to a key indicator — the average time between failures that lead to the inoperability of the entire system. Commanders and soldiers also reported that the latest version “enhanced the navigation and coordination of unit movements,” Guertin wrote.

Microsoft’s Integrated Visual Augmentation System (IVAS) is expected to provide US ground forces with a “heads-up display” similar to those worn by fighter pilots. It will allow commanders to project information onto a screen in front of a soldier and will include features such as night vision. The Army is projected to spend $21.9 billion over the next 10 years on AR glasses, spare parts and support services if all military requests are implemented.

The test results will be scrutinized by lawmakers, who will decide whether to approve the $424.2 million the Army has proposed to spend on the program this fiscal year. The House and Senate Appropriations Committees have separately proposed substantial cuts to the Army’s requests pending test results.

One finding that may make members of Congress think twice: soldier acceptance of the glasses “remains low.” Both they and their commanders said the glasses did not “contribute to their ability to perform their mission.”

Microsoft, which did not receive a copy of the test results, said its close collaboration with the military allowed it to quickly create and modify the device “to develop a transformative platform that will deliver enhanced soldier safety and effectiveness.”