High up in the mountains of Nepal, life seems idyllic. Rising up from lush cloud forests at lower altitudes are bare summits that literally take your breath away.

Yet living at altitudes of over 4,000 metres (13,000 feet), the proximity to nature is so close that the mountain people who live there are being effected by a factor that only ever seems beneficial: light.

In Human Planet’s Mountains episode, the BBC Earth team trekked up high into the impressive landscape to document the work of two doctors who were literally changing people’s lives in just 24 just hours.

This event was key to the Human Planet series, because it exemplified how humans are, as series producer Dale Templar said, “Without a doubt, the most ingenious, clever species on the planet.”

However, it also led to another fantastic event. Since airing in February 2011, and subsequently journeying all over the world, the program brought light and attention to the outreach team's work that had never been witnessed by a world-wide audience before. E-mails of compassion quickly began making their way to Drs. Ruit and Tabin, and before they knew it, they were flooded with support.

It is all for the work of two men, who made it their personal goals to eradicate as much unnecessary blindness in their lifetimes as possible. That caught the attention of a BBC Earth team, who in turn opened the eyes of millions of viewers…

The possible would still be impossible.

Not what you’d expect from a natural history documentary, but you should expect nothing less from BBC Earth. An excellent outcome, and most definitely a reason to celebrate human life on planet Earth.

This originally appeared on BBC Earth and was reprinted here with permission.