Tiny Tuesday: Technology

Blippers who know me won't be surprised that I decided to set "Technology" as today's optional theme for the Tiny Tuesday challenge, which I have the honour of hosting this month.

I initially expected to blip something electronic or electrical, but then I thought this bit of medical technology might be interesting. If you've ever had cataract surgery in the last 30+ years, you've probably has something like this intra-ocular replacement lens implant inserted. For those who don't know, a cataract is a cloudiness of the natural lens present just behind the pupil of the eye (it can be anything from the slightest mistiness to a full white opacification).

Warning: Don't read on if you're squeamish!

When the surgeon has removed the cloudy core of the lens, this leaves the transparent "shell" (capsule) of the lens intact with just a "window" in its front surface. The natural lens is about 10mm in diameter but the replacement lens only needs to be large enough to cover the pupil, which means it can be very light and therefore safer. The optical part of such lenses is generally 6-7 mm across, with springy supporting "legs" which can be squished down then sprung into the edge of the lens capsule, thereby holding the optical part securely in place.

Modern lenses are usually made of a soft, flexible acrylic and they can be folded (rolled up along their length) and inserted through a small incision - they then spring back to their normal shape once in place.

This particular example is slightly yellow as you can see. Some experts believe that filtering out the blue end of the spectrum helps to protect the retina (the "film" lining the inside of the back of the eye) from possible longterm damage from blue light, which the normal lens (especially as we get older) does anyway. The patient isn't aware of the yellow effect - especially as most older folk having this surgery have slight yellowing of their natural lens anyway.

Prior to the introduction of replacement lens implants, patients were left with no lens in their eye and needed very thick glasses which didn't really work all that well. The first lens implant was inserted in 1949 but it took several years before they were developed to be safe to be used widely - there were a lot of problems with the early ones.

Whoops, I've written much more than I intended - sorry, I can't help myself, I still have an enthusiasm for the subject after 35 years of working in the field!