Sunday, April 10, 2011

Who's the blindest of them all?

I have often found myself in near arguments with people over who had poorer vision. It's in some ways like a badge of pride to feel like you're getting through life with handicaps that others don't have. Anyway, it's a big deal to me. I've given a lot of thought about how having "low vision" can affect a person throughout their lives up to the age of 31. :) I can't think of a good way to make this less rant and whiny... so I'm just going to spew out my complaints and "wisdom."


Image from www.atlasaviation.com/medical/pilot_vision.htm


A legally blind person does not drive a vehicle. To be legally blind by US federal definition you have to show that, with the best glasses or contacts available on, your vision is still worse than 20/200 in your best eye. That means that what a person with good (20/20) vision sees at 200 feet, you see at 20 feet. The other option is to have a visual field of 20 degrees or less. A normal person can see about 135 degrees up and down and 160 degrees from side to side. To drive you have to have at least 20/40 vision.



Image from www.atlasaviation.com/medical/pilot_vision.htm


Some ways that I think having poor vision has affected me: I'm a life-long squinter. Before my surgeries, I could always see better when I squinted, actually putting physical pressure on my eyes probably reduced the astigmatism or changed the curvature of my eyes, and it helped. Now it's a habit that I just can't seem to stop doing. Of course it doesn't help that even after two big surgeries, Islena still sees better than me, even though she doesn't have perfect eyes, and even if I put my glasses on. I think some people mistake my squint for me being in a bad mood. Whatever.


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I have also noticed that there's a certain socially acceptable distance when you're supposed to say hi to an aqcuaintance when you see them in the street. In the case of a person with poor vision, you're always making educated guesses as to whether you know the person or not. Sometimes, you don't say hi to someone you know until that correct social time to do it has passed. Sometimes, you say hi to someone you don't know. This is especially embarrassing if you said their name in the salutation... or asked about their kids. Or how their pregnancy is going. Sometimes you wonder if they are wondering why you are staring at them. Really it's because you're about 60% sure you know them, but you want to be more sure before starting out the necessary salutations. Personally, I'm the guy that says "hey" to everybody. Know them, don't know them, it's all good. Or I just never look up at people, and if someone sees me and says hi, then I say hi back, with the excuse that I didn't see them.


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Another area affected by poor vision is sports. Naturally I was the wide receiver on my Freshman football team. Because who needs to see to catch a football under bright stadium lights with a helmet on, right? To my recollection I never caught a pass in an actual game.



Image from http://thesegentlemen.blogspot.com/2009_11_01_archive.html


I really think my vision was severely affected in school. I often sat at the back, and couldn't see the board in school. I should have sat at the front, but to sit at the front you have to be willing to let all the people behind you stare at your back and talk about you, or so I thought, and I wasn't confident enough to do that. I remember Mrs. Fawcette's Spanish class in particular. She must have been farsighted, because whenever anyone didn't seem to be able to read something that she was holding, she would back it even further away to see if they could see it better. I'm sure she didn't do it from malice, she just didn't realize that even at a few feet away, sometimes it was too far. Poor vision was only a small part of my school difficulties, but it was there.


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I have been in two accidents that were caused by me. In the first, my error was thinking that I could get by going 10 miles an hour slower than other vehicles in a snowstorm. I should have been going 20 miles an hour slower. I knew my car was light and had balding tires. The other was poor vision. It was early evening, and I was squinting up at the street sign to see what street it was long after a person with good vision would have known. There had been a rear ending collision less than a minute before I got there, and the two vehicles were stopped right on the other side of the green light. I looked down too late, and wasn't able to come to a complete stop before hitting the rear end of a vehicle that had rear ended another vehicle.


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I think in general vision is correlated to social and action related confidence. Seeing better means better information faster, which means better decisions faster. It's easy to get used to being the last person to understand a developing situation around you, or to see instructions or signs, or to notice others' body language. The good news is that it's fairly easy to forget about all of these differences, because if you've never seen 20/20, then really you don't realize what a difference it makes. If you've never walked around with 20/1500 vision, then you don't have to worry about it. It's only that moment of change, when you have a surgery, or new and better correction through glasses or contacts, that you really feel the difference that it makes.


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Anyway, my reason for writing this blog was to talk about my surgeries. They did my left eye first. My vision was too poor for lasik (reshaping cornea by removing tissue from the middle of the cornea) or PRK (reshaping the cornea by shaving off areas of the exterior of the cornea.



Image from www.atlasaviation.com/medical/pilot_vision.htm


My surgery was a lens implanted in the eye. It's similar to cataract surgery, except that they leave the original lens in the eye, and just put another one in. For the first surgery, they put a verisyse lens in. My understanding is that the lens was originally named for its creator, and called the "Worst Iris Claw lens." For some odd reason, this didn't fly with the marketing people. I still tell the occasional person that I have the Worst Iris Claw lens in my left eye. Actually I don't. But it would be funny if I did. At least for me.



Image from www.urmc.rochester.edu/eye-institute/lasik/procedures/verisyse.cfm


Anyway, they shot some holes in my cornea with a laser so that eye juice could still circulate after the lens wss in place. Then they cut a slit in my cornea, slid the lens through there clipped it into the front of my iris (colored part of the eye), and then closed up my cornea. You have to hold still while they shoot the laser into your eye. Otherwise... bad things happen. It's also a good idea to hold still while they take the knife to your eye to slice open the long narrow gash to get the lens in. When you have 20/1500 vision, you can focus on the tip of the blade until it is about an 1/8 of an inch from the cornea. Luckily I didn't have to worry about squinting or closing my eye because there was a speculum in it, forcing it open and making blinking impossible.


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For a similar experience in a non-clinical environment, I suggest staring at a 100 watt light bulb from about 6 inches away without blinking for a while, then stabbing the eye with a knife. I'm totally kidding. Kindof. They did all these things, but I wouldn't suggest the do it yourself home trials.


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The Verisyse surgery was followed by Limbal Relaxing Incisions. The implant helped get rid of most of my myopia (nearsightedness), but didn't do much for my astigmatism, which was also quite severe. Myopia and hyperopia (farsightedness) are due to problems of the eye being non-spherical in terms of being more like an egg shape (longer than normal front to back) or like a... flying saucer shape? Shorter from front to back anyway. Light is received at the cornea and focused back to a perfect point in the back. If the distance from front to back is too much or too little then the light doesn't focus at the right point, and you get nearsightedness or farsightedness. When the eye is an imperfect shape, like a pear with one side slightly larger or bumpy, then the light will never come together and focus at a single point. It focuses at differing points. This is astigmatism.


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Limbal Relaxing Incisions (LRIs) are designed to cut the cornea and make it looser to make the overall shape of the eye more even to reduce astigmatism. I apparently have very healthy resilient corneas, and they kept healing up as they had been after several LRIs. They like to wait to make sure the operated eye is ok before operating on the other eye. So a year or two later I got my right eye done. By that time, there was another lens available, that was placed behind the iris. The same holes in the iris for circulation were needed. This lens actually folded, so the cornea didn't need such a big slit cut in it. It was rolled up and passed through a small hole, and then opened up and arranged inside the eye. LRIs didn't work on my right eye either.


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For those that are interested, Lasik and PRK are options for people with up to about -10 diopters. Diopters are the numbers that you use to buy glasses. If +1.5 glasses work for you, you are at -1.5 diopters. Lens implants are for those between -11 to -20. My vision was -21 and -24 in my eyes. They helped a lot. At the end of the day, while I didn't get perfect vision, I did get to a point where I don't have to wear glasses or contacts. I have a new pair, but don't wear them all the time. I'm also a candidate for Lasik surgery, since the needed correction isn't so significant anymore. When I was ready for Lasik, my surgeon wanted me to wait a couple more years for my eyes to 'settle' to make sure I didn't have any complications. Since that time, I've kindof forgotten about it.

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