His voice became hoarse as Russell Leavitt, a retired 60-something eye surgeon from Oregon, tried to tell the story of a blind child he had treated whose sight was restored.

His sturdy hands, which had performed free eye surgery on the child, wiped the tears dangling from the corners of his eyes as he grasped for words to describe the power of the transformation. Finally, he surrendered to his emotions.

"I'll send you the rest of the story in an e-mail," he said.

Volunteering in West Africa on a hospital ship is not how most people would spend their retirement, but after handing over a successful ophthalmic practice to his son, Leavitt decided to do just that. He recently finished 4 1/2 months of service with the Mercy Ships' eye team, performing hundreds of thousands of dollars worth of free eye surgery, and restoring sight to the blind.

In sub-Sahara Africa, an estimated 5 to 6 million people are blind and 16 to 18 million are visually disabled. More than two-thirds of this blindness is treatable or preventable.

For example, an estimated 600,000 people per year go blind in Africa from untreated cataracts, which are routinely treated in Western countries with a 20-minute operation.

In Liberia, the situation is desperate; there are fewer than five ophthalmologists, and the general population does not have access to needed eye care. Men, women, and children slowly are losing their vision, productivity and independence while becoming an economic and social burden to their families.

But Mercy Ships is making a difference in the lives of individuals, one eye at a time. During this year's 10 months of medical service in Liberia, almost 1,200 free surgical procedures were performed.

Cataract and pterygium removal are two of the primary eye procedures performed on the Africa Mercy. A cataract is a clouding of the eye's lens, causing foggy vision and making it difficult to read or distinguish a friend's face, and it can cause total blindness if left untreated.

A tergum is a painful, irritating overgrowth of the eye's conjunctiva that can obscure vision. Pteridines are commonly caused by sun exposure, and are found in those living in tropical climates.

In a typical day, Leavitt performed as many as 12 surgical procedures while attending to the needs of the dockside eye tent, in which the eye team takes care of the admission, teaching needs and follow-up of every eye patient.

Eye surgery requires a steady hand to make precise, subtle incisions on the fragile and delicate eye, and involves a combination of intelligence, artistry and skill.

The amount and intensity of the work were exhausting at times, but a deep conviction and passion for the physical and spiritual restoration of the Liberian people kept this retired eye surgeon energetic and empathetic.

In the midst of his demanding schedule, he found time to pray with and talk to each individual patient after surgery. It was his favorite part of the day.

Sadly, the needs for eye care in Liberia are so overwhelming that for every person to whom Mercy Ships restored vision, there is a blind man, woman or child who still needs help. Having to turn away patients - whose only separation from sight was a 20-minute operation - because of a completely filled surgical schedule was always difficult.

After a day when several potential patients had to be turned down, Leavitt felt frustrated and discouraged because he could not help everyone. But as he walked past the eye tent, he noticed four white canes, which are often used by the blind, pushed to the side of the tent. Curious, he asked one of the eye team's translators where their owners had gone.

The canes' owners were gone. Those people could see and no longer needed them. The canes were now a memorial to four transformed lives.

Leavitt instantly felt encouraged. He realized the weight of the impact the eye team was having on individuals: the power of the gift of sight.

When he thinks of the hundreds of volunteers it takes to run a hospital ship and bring the gift of sight to the poor, Leavitt says, "I'll bet God is looking down and saying, 'Well done, good and faithful servants.' "

I'd have to agree.

To read previous parts of the series, visit http://go.philly.com/megan. For more about Megan Petock's experiences in Africa, visit www.megisinafrica.blogspot.com, or e-mail megisinafrica@gmail.com.