The couple remodeled their two-story townhouse near Guatemala City so he had everything he needed on the first floor and didn’t have to navigate stairs. Otto learned to use a trackball mouse with his foot to type with an on-screen keyboard. But it was cumbersome, and he needed Pamela nearby to move the cursor from one corner of his two 32-inch screens to another as he navigated Excel spreadsheets and Power BI dashboards.

A tracheotomy was put in his throat to help him breathe, taking away his limited speech and increasing his isolation. But when Knoke, who spends two hours a day reading blogs and researching, saw his friend Juan Alvarado’s post about the new Eye Control feature in Windows 10, he let loose with his version of a shout and immediately ordered the Tobii Eye Tracker hardware to use with the software.

Alvarado, who met Knoke as a database consultant working on the ATM system Knoke had implemented, hadn’t known about Knoke’s condition until he suddenly saw him in a wheelchair one day. And fittingly, Eye Control itself began with a wheelchair.

Microsoft employees, inspired by former pro football player Steve Gleason, who had lost the use of his limbs to ALS, outfitted a wheelchair with electronic gadgets to help him drive with his eyes during the company’s first Hackathon, in 2014. The project was so popular that a new Microsoft Research team was formed to explore the potential of eye-tracking technology to help people with disabilities, leading to last year’s release of Eye Control for Windows 10.

Knoke said it was “a joy” to learn how to type with his eyes, getting the feel of having sensors track his eye movements as he navigated around the screen and rested his gaze on the elements he wanted to click. Using Eye Control and the on-screen keyboard, he now can type 12 words a minute and creates spreadsheets, Power BI dashboards and even PowerPoint presentations. Combined with his foot-operated mouse, his productivity has doubled. He plans to expand his services to the U.S., where he spent six years studying and working in the 1970s. He no longer relies on his wife’s voice, because Eye Control offers a text-to-speech function as well.

“It was frustrating trying to be understood,” Knoke said in the email interview. “After a few days of using Eye Control I became so independent that I did not need someone to interact with clients when there were questions or I needed to explain something. We have a remote session to the client’s computer, and we open Notepad and interact with each other that way.”

His wife and his nurse had learned to understand the sounds he was able to make, even with the tracheotomy restricting his vocal chords. But now he can communicate with his three grown daughters, his friends and all his customers.

“Now when our children visit, he can be not just nodding at what they say, but he can be inside the conversation, too,” Pamela Knoke said. “He always has a big smile on his face, because he’s got his independence back.”

He’s also started texting jokes to friends again.

“It’s kind of like it brought my friend back, and it’s amazing,” Alvarado said. “Otto told me that for him, it was like eye tracking meant his arms can move again.”

Being able to text message with Eye Control has helped his business as well.

Grupo Tir, a real-estate development and telecommunications business in Guatemala, hired Knoke for several projects, including streamlining its sales team’s tracking of travel expenses with Power BI.

“Working with Otto has been amazing,” said Grupo Tir Chief Financial Officer Cristina Martinez. “We can’t really meet with him, so we usually work with texts, and it’s like a normal conversation.

“He really has no limitations, and he always is looking for new ways to improve and to help companies.”