Mama Moline is 58 and a grandmother of 12. She has cataracts in both eyes and severely impaired vision. Left untreated, doctors say she would be totally blind within six months.

She lives in Cameroon's capital, Yaoundé, which is where I got to meet and talk with her as she queued with hundreds of other men, women and children to be seen by the volunteer doctors, nurses and other staff of Orbis, bringing people together in the fight against avoidable blindness.

Because that's the thing...many eye conditions, including cataracts and glaucoma, can be treated, at least when they are found and operated on in time. In the UK, where our societal norm is to seek medical help when you notice there's an issue, there are half the number of people with cataracts simply because they are generally diagnosed and treated more quickly.

I'm sure I'm guilty of taking my own eye health a little for granted. Perhaps because I live in a country where medical care is so freely available and we don't have to pay unless we choose to. Perhaps because both my father and my cousin are ophthalmologists and have always been around to field any questions. When my own cataract was discovered unexpectedly - I was fairly young and it was picked up at a routine eye test - I simply walked out of the optician's with a referral letter for surgery, the operation was duly scheduled and all I had left to worry about was the fact I wouldn't be able to go to the gym for a fortnight after.

How very, very different to life in a developing country like Cameroon, where almost a quarter of the population live below the international poverty line of less than $1.90 a day. Here the rate of blindness is 20 times that of the U.K - a total of 181,000 people. And yet 75% of these cases would have been preventable.

At Yaoundé Central Hospital and the newly opened Magrabi ICO Cameroon Eye Institute (the first not-for-profit sub-speciality and testing eye hospital in the Central African Region) the team from Orbis hope to examine 366 patients in the course of their stay, with 235 of those receiving surgery or laser treatment as a result.

A number of these operations are performed on board the Flying Eye Hospital, a state of the art surgical facility which is flown around the world to the places most in need of sustainable healthcare systems.

The staff of volunteers trains local colleagues as they work, leaving behind them new skills that best serve the people who need them most.

Cameroon has many other pressing health issues including HIV and TB, which means eye health has to compete for very limited resources. But it's vitally important.

Blindness here generally shortens a child's life and certainly prevents them from thriving. Children without vision problems are shown to do better in education and, later, in employment.

Poor eyesight is a challenge for the whole family, the whole community, not just the patient who requires long-term support. Having the skills and the infrastructure in place to help can really make a difference.

Rather than being nervous about her impending surgery, Mama Moline is excited at the thought of being able to do simple tasks denied to her by her failing sight, and by the idea of how her life will change for the better.

The operation, performed by volunteer surgeon Dr Asim Sil, goes smoothly, and afterwards she is in good spirits, comparing notes with other patients who've just had similar surgery.

Yesterday her dressing was removed back at Yaoundé Central and she was thrilled to see the face of her son clearly for the first time in many years. Overjoyed, too, to have been given this sight-saving treatment which would otherwise have cost her between $150-250 per eye - money she simply doesn't have.

"I can see clearly!" she told me. "And I'm so pleased that the training of the local doctors means I can have the other eye done as part of the programme. I am very, very happy."

It's not just the local surgeons and nurses who are trained in best practice and new skills. Louise Garnham is 68. When she's not working part-time as an orthoptist at Moorfields Eye Hospital in London, she spends two days a week looking after her 20-month grandson ("hard work but I adore him.")

This is her 17th training mission for Orbis, and she describes it as "rewarding and life-enhancing. Learning is a circle - you never stop no matter how old you are. I'm happy to be doing something positive, altering people's lives for the better. It's a bit like looking after your grandchildren - the rewards are similar, it keeps you young and makes you go out and think about things. Both my sons are really proud."

My insight into life in Cameroon has been an extraordinary experience. It has really brought home to me how very fortunate so many of us are to have such easy access to such life-changing healthcare. To see what the surgery has meant - and will mean - for Mama Moline and her family has been something I will never forget.