Short-sightedness runs in my family and my seven-year-old daughter, who has just brought home her first pair of glasses, asked me if dogs could be short-sighted and what would happen if they were. Would they need glasses or an operation? I had to confess I had no idea whether dogs could be short-sighted, so I said I would ask an expert!
Graham Finch advises…
Aw, that first pair of glasses! As a fellow short-sighted dog owner, I too can (just) remember bringing home that first pair of glasses at a young age. I digress – thank you for an interesting question, which is not entirely easy to answer.
I have read that in humans, sight is considered one of our primary senses with the other senses perhaps taking a more secondary role. This is really an artificial concept – all of our senses combine to produce a holistic perception of the world depending on the context. For example, in pitch dark, our hearing and touch become more vital.
My understanding is that most dogs are probably short-sighted, with some breeds being more so than others. Research has also shown that dogs are unable to distinguish red and green, seeing these colours in various shades of grey. Whereas a normal person’s vision is usually measured as 20/20, it is estimated that dogs’ vision is 75/20 – which means our canine friends would not be able to apply for a driving licence!
However, context is key here; a dog’s primary sense is considered to be smell and this goes far beyond anything we can imagine. I have read that, should an owner fingerprint a window, their canine companion will still be able to distinguish the scent six weeks later (in spite of cleaning). I think we should therefore consider their ‘poor’ sight in a holistic context and I suspect it is hard to imagine how they sense the world. Sadly, I come across a number of totally blind dogs and, in the vast majority of cases, this does not seem to significantly affect their quality of life once they have adapted.