To say ophthalmology is a passion for Dr. Bill Wilson, 62, and his wife, Mary, 59, is an understatement. For more than 30 years the husband-wife team has volunteered their time worldwide to restore sight to people blinded by cataracts.

Their latest medical exercise, Medical Readiness Training Exercise (MEDRETE), took place in Zanzibar, Tanzania, where both Bill and Mary performed free cataract surgeries at the Bububu Military Medical Hospital, January 30 - February 10, 2012. They worked with ophthalmologists from the U.S. Army and the Tanzanian People's Defence Force.

The two-week MEDRETE is an ongoing U.S. Army Africa bilateral exercise that improves the relationship between host nation medical providers delivering free medical service to citizens in need of treatment.

Bill's first association with USARAF was during MEDREACH 11 in Malawi, May 2011, where he was in charge of the group of ophthalmologists performing cataract surgery. However, Bill said he has participated in many of the military-sponsored eye missions that use the suture-less cataract technique -- a technique he helped bring to the U.S. Army.

"We're very fortunate to be sponsored by the U.S. Army to come and restore sight to the blind. Of all the things in medicine, there's no greater reward than restoring sight. It's the thrill of a lifetime, even when it's repeated thousands of times," said Bill, a retired U.S. Army colonel.

The suture-less cataract surgical technique used in the surgery, known as Extracapsular Cataract Extraction, was introduced to Bill more than 10 years ago while he was in Nepal. He noticed the technique was cheap, low-tech and required minimal post-operative care, and realized it would be ideal in developing nations.

After mastering the technique, Bill was able to train the ophthalmologists in the U.S. Army to use the suture-less technique.

"The U.S. military has great ophthalmologists who are very well trained -- they have great skills, [yet the opportunity to broaden their knowledge has been limited,] so it's very neat to see them teaching host nation ophthalmologists how to change the quality of eye care in their country," Bill said.

Mary, a graduate of the University of Maryland Nursing School, also uses her experience to help other nurses in the ophthalmology field.

"We've done a lot of these missions so we've developed a method. We get a lot of different nurses that come and do these missions, but when I'm here I can train them and show them what we have done in the past that's been successful," she said.

Their vast experience has not only made Bill and Mary more familiar with successful techniques, but also with how each other works in the operating room.

"I did most of the surgeries with him. I can usually predict what he needs, but he usually throws me off once in a while," Mary said, laughing. "I know him very well so I know how he likes to operate."

As their experience grew, so did their passion for restoring eyesight.

"Those of us in the medical profession consider ourselves incredibly privileged to be in this position to perform this service. It is truly a privilege to have the God-given ability to interact with somebody, and then in merely 20 minutes perform life-changing surgery," Bill said.

Mary shares similar feelings about the opportunity to change someone's life.

"My favorite part is when people take the patch off. When you see someone who is blind, and you take the patch off and they can see, there's a gamut of emotions. We've seen people cry, we've seen people dance, we've seen people just jump for joy -- I love seeing their faces," Mary said.

Even though Bill and Mary may not get paid all the time for their work, both agree this experience is rewarding and gratifying.

"If we charged for all the lenses we put in, we could be millionaires. But that's not what it's about," Mary said.

As MEDRETE comes to an end, they talk of future plans to continue traveling overseas to perform cataract surgery.

"It's what we've been doing for 30 years and that's what we plan on doing as long as we have the health," Bill said.