This is an easy one! One study found that the return on investment for cataract surgery was 4,500% in terms of contribution to personal and national wealth and the avoidance of direct and indirect healthcare costs. That’s a little hard to get your mind around, but the point is its a very big number!

But isn’t all health care that good? Definitely not. A survey across the 38 nations of the OECD found that 20% of the healthcare treatments we receive are of no perceptible benefit to us as we receive them. That is sobering. We do what we’re told by our doctors (on the whole!) but sometimes we wonder about the =value of treatments or surgeries we have been received. 

But you can see the problem with this answer. We aren’t machines and to measure what use we make of something like cataract surgery misses the point. How do you measure or put a score on the pleasures of sight? The independence maintained, stumbles and falls avoided, the ability to read the 80% of non-verbal communication in every conversation which comes from reading peoples faces. The hobbies maintained. The social opportunities re-captured. And so on. Vision accounts for half of the brain’s senses and all the others (taste, touch, hearing, smell, temperature, balance) all together make up the other half. 

Many eye conditions are difficult to treat and though medicine is making advances all the time, sadly some effects of age or illness on the eyes are hard to treat. But cataracts rank as one of the safest procedures yet devised and like vaccination and air travel is one of the best blessings of being alive now rather than a century ago!