When I have new elective students we always look at the animals that are in our hospital for non-ophthalmic problems, to see what is normal in the eye. But this lovely French Bulldog we saw yesterday clearly isn’t normal! What are these circles doing in the eye and what is the blob in the middle, if you’ll excuse me getting a bit technical!?
This dog, in with us for pituitary problems, has had successful cataract surgery elsewhere and what you are looking at are the circles within the intraocular lens (IOL) that has been implanted to correct the hypermetropia (long sightedness) resulting from removing the lens. The ‘blob’ in the middle is new cataract forming on the lens capsule, what is known as posterior capsular opacification (PCO).
This degree of lens change probably doesn’t make a huge difference to the dog – a fair few labradors have this amount of cataract as an inherited defect for life without anyone noticing the difference! But if it gets worse it can cause blindness and in human cataract surgery it is huge problem as it stops people reading the small print and driving. Thankfully neither of those were high on this dog’s wish list!
Kim Young Sam comments that IOLs are meant to reduce PCO. That can happen by preventing migration of epithelial cells to the lend capsule in the optic axis, though in this case PCO hasn’t been prevented.