The tale of a cataract as told by an astrophotographer
Sight, in humans, is quite a popular thing. People regard it highly, and do seem to think it's an overall good idea.
My experience of sight has been, like most other people, a given. It started great, and as a kid my family would occasionally use me to find things, like shop signs, in the distance. Of course, it does deteriorate over time, and I've worn glasses since early university. It started just for reading, but soon I was wearing them full-time.
It turned out that apart from being long-sighted, I had astigmatisms which were reasonably severe, and getting worse.
You get old
Eventually I wasn't able to look through telescopes any longer: unless I had an eyepiece that I couldn't afford, the eye relief - the required distance between the eyepiece and your eyeball - was so short that I had to remove my glasses. Without glasses, of course, all I could see were comets. No, they weren't meant to be there.
Resignedly, I gave up visual astronomy and went deeper into astrophotography. A screen is easier to look at.
The tipping point
Last year I got new glasses. Nothing unusual, it's just that the prescription was getting a bit old and I felt that it needed an update. I took myself off to the local optometrist and had the standard consultation, and collected the glasses a few days later.
However, it was only a few weeks after that that I noticed my right eye - my dominant eye - wasn't much good any more. Was the prescription poor? Had the optometrist done a bad job?
I went back and they had a closer look. It was a cataract.
Cataracts. Not gorgeous.
Cataracts are a gathering opacity in your eye lenses.
In my case, for some reason it seemed to become a lot worse in a short time. Mine was... sort of a bit bad. One of the machines they were using to assess my retina wasn't even able to see through it to the back of my eye.
They're also sneaky things. They creep up on you slowly over time, and you don't notice it until it gets very bad. Because cataracts develop so slowly, you don't get a good idea of what it is like to look through one until it's removed.
I was told that I was looking through a dirty yellow filter. Astronomers know exactly what it's like to look through a yellow filter. I'm no exception. I've sold yellow filters for years, and I certainly hope the ones I've sold have all been nice and clean.
But I can calibrate for colour
The thing about a filter is that it colours everything you're looking at, but (depending on the filter) you can still tell, to an extent, what colours you're looking like. Blues look a browny-green, reds look a browny-orange, and greens just look washed out.
Your brain gets used to this, and re-calibrates itself. All very clever, but if you're looking through that dirty yellow filter all the time, you forget what colours are supposed to look like.
And I'd been looking through my cataract for so long that I didn't know what real colours were
Colour wasn't the problem that got me in the end. Everything had become so cloudy that what I was seeing was very fuzzy. The surgeon described it as microscopic bubble wrap. One cold night, several years ago, I was photographing the sky and dew began forming on my telescope's objective lens. Thinking about it now, this was very much like what I was seeing with my eyes.
I can't calibrate that out
The other eye was still reasonably good, and by comparing the two, it became more and more obvious that my focus was badly astray.
So finally, I took myself off to some qualified people and set in train the removal process.
The solution: cataract removal
So, just yesterday, I had the cataract removed. Rather than simply removing the bubble wrap, the surgeon removed the entire lens and replaced it with an artificial one.
The removal operation was quite a short affair, and because of the anaesthetic I don't remember much about it at all. What I do remember though, is the surgeon drawing on the surface of my eye with what appeared to be a tiny felt-tipped pen. I felt like a white board. It's a testament to modern anaesthetics that I didn't actually scream and run away at that very point, but I was feeling very much at one with the world.
I was sent home with a nice fat eye patch and an unaccountable tendency to say "arrrrr" at the start of every sentence.
This morning I visited the surgeon to see how it had gone. All seemed well - or at least the surgeon didn't let on otherwise.
On removing the patch I was given the pure, glorious vista of looking through a clear filter after having seen fuzzy yellow for years. Seriously, and I'm not exaggerating at all here - it was nothing short of a miracle. Anyone who has had the same experience will say the same.
After the operation, the dilating agent they had used was still working. So going outside, the astrophotographer in me saw everything as overexposed. In particular, the highlights were totally blown out. No amount of post processing can get those pixels back. But I still felt like singing.
My right eye is now (just a day later) returning to its normal exposure, and I'm seeing another effect. Highlights are surrounded by circular halos which are quite intrusive - it's nearly identical to a reflection I get in my filters. I could figure out the reflection angle with a little trigonometry, but I don't know my eye's f-stop. I'm assuming it will pass: there's still a good amount of swelling around the eye.
So now what?
I feel a little like Steve Austin, the Six Million Dollar Man - or perhaps, to show my age only a little less, one of The Borg from Star Trek TNG. Not only is the lens I now have clearer and not yellow, it's not astigmatic. This was what had chased me away from visual astronomy in the first place.
I went out this evening to see if I could get "first light" on some stars. Alas, Melbourne's clouds have ensured that what I expect may be a fairly emotional reunion remains in the future. Not too far, I hope.
I'm looking forward to being able to look through telescopes again - and specifically, the ASV's 40 inch monster in Central Victoria. Possibly the only disadvantage is that I'll have to invest in eyepieces for my triplet refractor.
..and maybe even give up that astrophotographer cred of saying (somewhat loftily) that I don't own an eyepiece.
Now I only have to wait for lockdown to be over.