Categories
Vision

One quick eye-related update

We went out to dinner this evening, and by the time we drove home it was twilight and all the cars had their headlights on. And that really sucked: my myopic left eye was overwhelmed with glare from every light source, and it really interfered with the image from my “new” eye. I reduced the problem by closing my left eye whenever possible, but of course my depth perception instantly disappeared.
So I think I’m going to have to minimize night-time driving until after my second operation. Bummer.

Categories
Vision

New eye #1, after one week

Herewith an update on the progress of my lens replacement procedures. It’s now six days since the procedure; this time last week I was enjoying a last glass of wine before going “nil by mouth”, knowing that I’d be alcohol-free for a couple of days after the procedure.
Things continue to go well. I had another follow-up visit today: my intraocular pressure is still up a bit (currently 25, expected value 21 or lower), but my doctor is unperturbed by this. My new eye still tests at 20/20; I rattled off the tests easily, and suggested that we should perhaps test at 20/15…. My final checkup for the right eye will be on October 11, and we’ll do the prep for the next procedure at that appointment. Then I’ll have my left eye done on October 18.
Over the last week I’ve been focussed on five issues: glasses, driving, protecting the eye, working, and eye drops. The glasses have been the most frustrating. I’ve been ignoring the “old eye” and concentrating on making things work for the new, far-sighted eye, and I knew that I would need reading (and computer) glasses. Eventually (in November) I’ll get prescription lenses, probably progressive, but for now I’m stuck with off-the-shelf glasses from my local pharmacy. Ostensibly, these come in a variety of strengths; in practice, I’ve found the descriptions to be useless. I’ve tried dozens of reading glasses, and bought four different pairs, but I’m not really happy with any of them. One thing that I forgot (basic optics – doh!) is that reading glasses are convex, and convex tends to mean chromatic aberration and barrel distortion. So all of my reading glasses have various degrees of chromatic distortion, and straight lines simply aren’t. Sigh. On the other hand, I have finally bought myself some decent aviator-style sunglasses, which are exquisitely comfortable. For the first time in my life, I have the sunglasses I want.
Driving has been OK, but it requires some care. I started driving on Sunday, without any corrective lenses (except for sunglasses). I discovered that I tend to augment my situational awareness with a lot of quick glances in the left and right side mirrors, without moving my head. This means that left side mirror checks involve just my left eye. But that’s the old eye, which is currently uncorrected. Oops. So now, I have to deliberately move my head to check my mirrors, just like I had to do when I was taking my Massachusetts driving test in 1981. Apart from that, things work OK. My brain tends to use the clear image from my right eye, but to supply some limited depth perception from my fuzzy left eye. The biggest problem is that my commute is the wrong way; in the morning and in the evening I find myself driving into the sun, low on the horizon, and even with decent sunglasses my “new eye” gets overloaded, which results in my left eye taking over.
Protecting the eye. Well, yes: I have to. (Remember those videos: this procedure uses a suture-less incision.) So I bought swimmer’s goggles to protect my eyes in the shower. I hadn’t realized that they were seasonal items; I had to go to a hiking goods store to find some. And I’m supposed to sleep with an aluminium shield over my eye, so that I don’t rub it in my sleep. On Saturday I took a nap, and woke up in a panic when I realized that I was rubbing my unshielded eye. Since then I’ve been obsessively careful about using the shield, taping it down so tightly that I now have a bruise on the side of my nose where it rubs.
Working. Sigh. This has been a pain. The simple fact is that if I read (and write) on paper or screen for more than 20-30 minutes, I get eye-strain and a headache. (I feel one coming one right now, as I write this blog piece.) This is really inconvenient in my line of work. All I can do is pace myself, and crave indulgence from my colleagues.
And finally, my life is dominated by those bloody eye-drops. Three times a day (I’ve settled on 8am, 3pm and 11pm), three different drops (Nevanac, Vigamox, Durezol), five minutes apart. And the instructions are to continue until the bottles are empty, so I have no idea how long it’s going on for.
But setting all that aside… today, after my doctor’s appointment, we stopped at Starbucks and sat outside with our coffee, and I marvelled at the clarity and delicate colour of the trees lining El Camino Real, seeing them with – literally – fresh eyes. It was wonderful.

Categories
Vision

First, the right eye…

Yesterday morning I had the first of two operations to replace the cataract-ridden lenses of my eyes with synthetic replacements. Everything went smoothly, and I now have 20/20 distance vision in my right eye.
We got to the surgery center at 6:15am,and the worst part of the morning – having an IV inserted less smoothly than usual – was soon over. I’m used to having eye drops to dilate my eyes for examinations, but for the operation we went a bit further. After the usual drops, the nurse placed a tiny drug-soaked sponge (about the size of a grain of rice) under my eyelid, and taped my eyes shut for 20 minutes. The result was suitably impressive. (Iris? What iris?) I spoke briefly to the anesthesiologist, who had previously handled one of my kidney stone treatments, and then I was whisked off to the operating room.
Although I was awake for the procedure, I don’t remember many details. The staff spoke very little, so I couldn’t even cue off their interactions. It seemed to go very much the same as the videos that I linked to in my previous blog piece on the subject. From my side of the eyeball, it was a spectacular light show: mostly pulsating yellows, reds, and cyans, with occasional periods of intense blue and green. There was no discomfort at all. And suddenly I found myself being wheeled into the recovery room, and given a drink of apple juice.
The following morning, I was back at the doctor’s for a post-op check. The pressure in my eye was slightly elevated, which is not unusual, and the doctor applied some eye drops to help to reduce it. As for reading the eye chart, I rattled off the 20/20 line with little difficulty. So now I simply have to keep taking the eye drops until all three bottles are finished, protect the eye against water and rubbing (I sleep with a shield taped over the eye), and show up for another check-up next week. And then in October, after I get back from the OpenStack summit in Boston, we’ll go through the whole procedure again for the left eye.
So what’s it like? Well, the clarity is amazing. I spent most of yesterday with my left eye taped shut, so I could concentrate on the new lens. (I keep wanting to call it my “new eye”.) Things are in focus down to about two feet; closer than that I need reading glasses. I’ve tried a couple of different strengths from the local pharmacy, but I still haven’t got used to them.
Without the clouding of the cataracts, everything looks much brighter, cleaner, and less yellow. At first it was quite amazing, particularly as I tried blocking first one eye and then the other. A chair which I had always thought was olive green now appears simply grey, while a wall that I had seen as cream-colored is now bone-white. However 36 hours later I’m starting to take the brightness and color shift for granted. (This may also be due to the return of my eye to its usual size.)
With my “old eye” patched, I obviously lost depth perception, so I’ve been trying to work with both eyes open. At distance, or when watching TV, my brain seems to take the clear image from my right eye and ignore the fuzzy data from my left, although I do get some slight sensation of depth. Reading or working with the computer is tougher. I use a pair of reading glasses, but the visual sensations are quite inconsistent as I move my eyes across the screen or from the screen to the keyboard. It’s quite a strain, and I can’t do it for long without getting a headache; if that doesn’t improve, I may have to revert to an eye-patch. Obviously I’m not going to be driving for a couple of days, but on Sunday I hope to be back behind the wheel. I’ll let you know how that goes.
Perhaps the biggest change, and one that I didn’t anticipate, is the result of a lifetime of myopia. Ever since I was a very small boy, when anything was visually unclear, or required careful attention, my instinct has been to bring it close to my eyes. If I was trying to disentangle a knot, or thread a needle, I would remove my glasses and peer at the object as close as possible. Suddenly, my world has been turned upside down: the closer I bring things, the less clearly I can see them. For some reason, this simple inversion affected me quite profoundly.
Overall, I’m simply delighted. The next couple of weeks, with one “new” and one “old” eye, are going to be a bit weird, but I don’t anticipate any problems. And I can’t wait for the next operation….

Categories
Geek

Countdown to cataract surgery

So I’ve started the countdown to my first cataract surgery. I wasn’t going to blog much about this, but I’ve found that although the web is full of text and video links for cataract surgery (in humans and other animals!), most are commercial or professional pieces. There seem to be relatively few first-person accounts of what it’s like to experience lens replacement. And since it’s a really cool technical fix, it’s worthy of the “Geek” tag.
I’m having my right eye operated on this Wednesday, September 21; the left eye will be done on October 18. In preparation for the surgery, I’ve just started eye drops three times a day: Vigamox (an antibiotic) and Nevanac (an anti-inflammatory). The pre-op tests took place on September 6, when they measured the interior and exterior geometry of my eyes using an ultrasound device; they’ll use these numbers to choose the right lenses for my replacements.
In peparation for the experience, I’ve been reading up on the subject and watching a number of videos. The best (lengthy) discussion of the subject is this lecture from UCSF:

For a quick presentation of the actual procedure, this video is good, though rather low-res:

One of the things I’m particularly intrigued by is how much difference I will experience in my vision. Yes, I know that my eyesight has been getting increasingly poor – my right eye is around 20/80 – but the deterioration has been gradual enough that I probably didn’t notice the changes. I’m really curious about how my color perception will shift. In some areas I’ve noticed the changes – increased glare during night driving, for instance – and I’m looking forward to improvements there. I just read an interesting piece by an ophthalmologist who himself had to have cataract surgery; as you might imagine, he was keen to document the experience carefully. (And it changed his professional outlook completely.)

Anyway, more and more of you will be going through this process over the next few years, so I’ll try to blog regularly about what it’s like.

Categories
FAIL

Quote of the day: on proportionality

The amazing thing about this crisis is the extent to which suffering and responsibility are completely out of proportion with one another. If you think about the people who are really suffering in the developed world today, none of them were executives at major banks, none of them were politicians involved in the construction of the euro, none of them were senior financial policymakers in any government, etc.

…via Matt Yglesias at ThinkProgress

Categories
Cloud computing

NoSQL at Yahoo!

One of my colleagues, P.P.S. Narayan (known to all as PPSN) is giving a talk next Thursday (September 22) on NoSQL storage services at Yahoo. It should be very instructive and entertaining. You can find out more here: Scaling Yahoo! – NoSQL in the Cloud – Database- Eventbrite.

Categories
Philosophy

More "Personal Incredulity"

Over at Camels with Hammers, Daniel demonstrated that the “Argument from Personal Incredulity” is not restricted to mysterians or theists. I tried to post this as a comment, but for some reason it wasn’t approved, so I’ll repeat it here:
Daniel wrote:

I share the suspicion that robots could not have an internal, subjective side of experience.

To which I responded:
Sounds like an argument from personal incredulity to me. Let’s unpack it a bit. Are you a dualist? If so, then you can certainly argue that there is some essential difference between a human brain and a robot brain; you just have the thorny question of explaining how it is causally efficacious. If not, then you have a different kind of hard problem: to explain why it is impossible to create a synthetic substrate which can function in all the functionally relevant ways that the spongy grey stuff in your skull does.
Now perhaps you are arguing that in practice based on currently available technology, such a thing is impossible. Even there, I suspect that you are indulging in a little species-chauvinism. We humans have a natural tendency to exaggerate the competence of our brain function. We actually observe, reason, remember, pattern-match, infer and deduce far less than we imagine we do, with much less accuracy or consistency, and we confabulate like crazy to fill in the gaps when this becomes apparent.
Introspection is simply a form of feedback loop: a process in which a part of a complex system monitors and reasons about the operations of the system itself. Such feedback loops occur all over nature – and engineering. (Check under the hood of your car.) They are fundamental to basic processes like homeostasis, learning, and troubleshooting. It is highly implausible that a sophisticated robot would not incorporate such design patterns.

Categories
Books

Review: Ready Player One

Here’s my Amazon review of Ernest Cline’s “Ready Player One”:

Simple Wonderful (five stars)
The 80s were an interesting decade: the first personal computers, the first video games (in arcades and in the home), the first music videos, and a string of wonderful movies that brought together teenage angst, over-the-top technology, exuberant fantasy, and epic quests. So what would seem more natural than to wrap up all of these themes into the ultimate epic video game quest of all time? What better distraction could we have from the dystopia of The Decline And Fall Of Just About Everything?
Read it. Just read it. I wish Douglas Adams was around to endorse it. And I hope you feel the same guilty pleasure that I experienced each time I worked out a puzzle before the protagonist had got there. (Isn’t being competitive what this is all about?)
And now I have to go and dust off my PS3 and kick some zombie butt….

Actually I have just acquired a PS3, but my game of choice is Soul Calibur IV. So rather than hacking zombies, I’ll be chasing sword-fighting maidens in skimpy clothing and High German knights in blood-stained armour…

Categories
Hmmm

What leads to the Argument From Personal Incredulity?

I just finished reading the slim account of a debate between Dan Dennett and Alvin Plantinga, entitled “Science and Religion: Are They Compatible?”.

Dennett’s conclusion is straightforward:

Plantinga wanted to show… that science and religion are not just compatible: Science depends on theism to underwrite its epistemic self-confidence. […] [But] Our capacity to discover the facts, and to have good reasons for believing that we have done so, is explicable without appeal to inexplicable or irreducible genius, immaterial minds, or a divine helping hand. […] Let Plantinga, like Behe, try to show us the irreducible complexity in our minds that could not possibly have evolved (by genetic and cultural evolution). He will find, as Behe has, that his inability to imagine how this is possible is not the same as a proof that it is impossible. Richard Dawkins calls this the Argument from Personal Incredulity, and it is an obvious fallacy.

This fallacy — the Argument from Personal Incredulity – is one that has always fascinated me. Of course many (?most) people who say that they “can’t imagine how X could have happened” have probably never actually tried to imagine it: they have a prior commitment to a position that holds that it could not have done so, and that’s good enough for them. And in some cases they may lack the background to actually reason about the subject. But how about the others? What factors might underlie an honest, good-faith Argument from Personal Incredulity concerning the reality of evolution, from the origins of life to human consciousness?
It seems to me that there are a number of failures of imagination which, while individually innocuous, could have a cumulative effect. Let me list a few of them; I’m sure that you can think of others. Each of these items warrants a lengthy exposition, but for now let me simply summarize:

  • Lack of appreciation of very big (and very small) numbers. The enormous age of the planet (143 Petaseconds). The vast number of cells in an organism – or on the planet. The short time needed for a chemical reaction to play out, or for a mutated gene to thrive or be extinguished.
  • A tendency to think backwards, deterministically, all-or-nothing rather than forwards, incrementally, in parallel, with contingency. This builds on the large numbers involved: the entire planet (and indeed the universe) is full of experiments in selection, all proceeding in parallel, all interacting, and all subject to myriad contingencies.
  • Lack of appreciation of how much can be accomplished by so little. To understand the power of complex systems, start with simple ones. Look at the range of capabilities of single-celled organisms, or artificial life systems. Now apply scale and parallelism to these simple components.
  • Hubristic over-confidence in the capacity and ineffability of the human mind. Our brains are good at handling fragments of analysis, recognition, inference, and recollection; they’re also quite good at weaving together a story to fill in the gaps and fix up the mistakes. We “remember” things we haven’t seen, and “decide” to do things that have already started. (Philosophical arguments about mental capability – things like Searle’s “Chinese Room” and Jackson’s “Mary” – assume a total competence which is demonstrably at odds with the way the brain actually works.)