I'm working on an answer for you, but your question is too difficult for a short answer. You can either check this HN submission in a few hours, or contact me b

I'm working on an answer for you, but your question is too difficult for a short answer. You can either check this HN submission in a few hours, or contact me by email (in the 'about' of my HN profile). EDIT The spectrum (pun intended) of vision issues is an exceedingly vast and complicated field. Your eyes are the biggest part of the equation, but it's actually more than just your eyes; how your brain tends to evaluate the things you see also comes into play. Though there are generally defined groupings and descriptions of issues, it's very important to remember that your eyes (and brain) are specific to you. The odds of two people "seeing" things in exactly the same way are minuscule. This still stands true for even physiologically "identical" people such as "identical" twins. Figuring out what works for you personally will involve a good deal of trial and error experimentation. Line length is just one example out of thousands. Have you ever wondered why HN and the essays at paulgraham.com both have long pages with narrow columns of text? --In one of Paul's essays/pages he explains how narrow columns of text are easier for him to read, and since both HN and his own site are his to control, he "wastes" a lot of horizontal space to get what he wants. For many people, scanning/reading a long horizontal line is difficult, or better said, more difficult, than scanning/reading short horizontal lines. This is one of the many reasons why printed newspapers use narrow columns of text, and why one of the well accepted styles for academic papers is to use two narrow columns of text per page. Of course, for some people, long horizontal lines are not a hindrance at all, so they might wonder why so much space is being "wasted" to achieve narrow columns. At least some of the endless wars of opinion on the "correct" way to format code are simply manifestations of the differences in the way people see. For example, if your eyes/brain have no difficulty parsing long horizontal lines, then you'll be more inclined to use them, but of course, you'll undoubtedly be at least annoying all the people who have trouble with reading long lines. For some people, the long lines may actually result in pain due to eye strain/fatigue. Type Faces (Fonts) and Type Sizes Just as PG has difficulty with long horizontal lines of text, my brain has difficulty with most type faces (fonts), and even more difficulty with switching between varying type sizes. I love books, but the typography of most books makes reading them far more difficult, and painful, than they need to be. The same is true for websites, PDF files, and other documents. On a computer I can force my preferences of type face and size on whatever I'm trying to read. It does take a lot of effort to learn how to configure browsers and other programs to over-ride the style of all websites and documents, but for me, the results are worthwhile. Foreground and Background Colors/Brightness This is one of the most wide spread and well known problems causing eye strain on computers, but due to fads and fashions, it may never be fixed. The typical dark foreground text on white backgrounds on computers is just a skeuomorphism carried over from printed pages of black ink on white paper. The trouble is, paper pages reflect light, but computer displays generate light. The best way to understand this problem is to pick the brightest lightbulb in the room where you're sitting, and go over and read the wattage off the top of the bulb. If you're a smart person, you turned off that light bulb before trying to read the wattage numbers on the top. If you're a not so smart person, you stared into the sun while trying to divine the nearly indecipherable written text. If your eyes are normally sensitive to light, then you only caused yourself some mild discomfort when reading the lit lightbulb. On the other hand, if you're one of the people who are extremely sensitive to light (sometimes called "light allergic" in less accurate terms), then by reading the lit lightbulb, you just caused yourself a memorable amount of pain. You can solve this problem by configuring your text editor, browser, PDF reader, operating system, and other programs to use a "dark" theme or "Reverse Video" mode. This problem is common enough for even the iPad to have a "Reverse Video" mode available in its options, but to be honest, I forgot what Apple called the feature. Be warned, what works for you might be ugly and it may even unforgivably offend your more fashionable peers. Fuck em. Seriously. Just fuck em. It's your eyes/brain/pain. If what works for you is green text on a black background with a single sized fixed pitch font, then use it. It might be hideous, but avoiding the pain of eye strain is far more important than the nuisance of having to put up with the occasional Matrix jokes. One important issue to be aware of is color deficiency. Many people are color deficient, or even color blind, and this is particularly true for older males. Any eye exam can help you know a bit more about what your eyes can see easily, and help you pick what looks good to you. Lastly, both color saturation and brightness levels on your display are worth testing to see what works for you. Screen Reflectance (Glossy Versus Matte Finish) I always love to joke about the reason why Steve Jobs always wore black turtleneck shirts because without them, he would be able to see anything on the glossy screens Apple always uses. Oddly enough, there may have actually be some truth in my little joke, but I'll never get the chance to ask him. Anyhow, some people have no trouble focusing through a reflection to the content on the other side, but for other people, reflections mean constantly switching focus from the content to the reflection and back. The result of the excessive switching is often eye strain and pain. If you have a screen with a glossy finish, then you have two choices; (1) replace the screen with something that has an anti-reflective matte finish, or (2) get a anti-reflective filter for your existing screen. NOTE: This is NOT a "privacy filter" but instead is a thin plastic anti-reflective sheet that you stick to your screen. The sticky sheets are removable, so you don't need to worry about making a permanent change to your monitors. PRO_TIP: Use an electric blanket to warm up the sticky sheet before applying it. Surprisingly, the opposite problem also exists. A glossy screen is, by definition, more transparent and causes less distortion. Any anti-reflective filter you use, whether a built-in coating or and add-on sheet, will reduce the focus of the underlying content. Some people have a great deal of difficulty with reading/seeing unfocused content, and like everything else mentioned so far, the result is increased eye strain. Refresh Rates and Dot Sizes The biggest loss in the move between CRT (tube) based displays and newer LCD (flat) displays is the latter typically has a fixed or "native" refresh rate. On older high-end CRT's, you can achieve very high refresh rates if you configure the display and graphics hardware properly. If your eyes/brain have difficulty with bright things flashing at you, then the refresh rate of your display becomes very important. Higher refresh rates are always better for reducing eye strain, but they can be extremely expensive. Most consumer equipment has a refresh rate around 50-60 Hz. The more advanced (and more expensive) equipment can exceed refresh rates of 120 HZ. The trouble with LCD's is, exceeding the "native" rate of the LCD panel component doesn't actually give you an increased refresh rate, regardless of what your settings are. In other words, the LCD might be perfectly happy to lie to you. Though non-metric, "Dots Per Inch" (DPI) is the common measure of how many points of light are within a given horizontal or vertical line. The stated number is usually symmetric across both horizontal and vertical axises, but not always, so you need to pay attention when reading the specs of a display. The more dots you have, the better. Well, at least more dots is usually better unless you are exceeding the native resolution of an LCD. Again, most all LCD's have a "native" resolution. You might be able to drive the LCD at a different resolution, but the results are suboptimal. Environment Lighting Though it's somewhat covered above in "Screen Reflectance," as more light falls on you and things behind/around you, the worse the reflection problem will be. On the other hand, some people have difficulty with switching between light/dark environments causing strain, so a well lighted room can also be a good thing. Some people need a well lighted room to watch TV, and others prefer a dark room like a movie theater. There are some people who simply cannot endure florescent lights without ending up in a great deal of pain. It's a well known problem but there are a handful of different causes. In some cases it has to do with the frequency of the generated light. In other cases it has to do with the flickering caused by the ballast, poor circuit isolation, poor quality mains power, or even interference from other electrical fields. Sometimes the easy answer is to just shut off the over-head florescent lights and use a normal lamp, with a natural spectrum incandescent bulb, plugged into a small Uninteruptible Power Supply (UPS). Of course, since people are different, some can't handle natural spectrum incandescent bulbs (e.g. overly sensitive to near infrared light), and others can't handle the spectrum of light provided by typical (cheap) light bulbs. Using a small UPS is optional, but if your building has dirty mains power, then the result will be the brightness of the bulb constantly changing. Even if the change is imperceivable, it can still cause eye strain, just like the flickering of florescent lights. If you're unable to shut off the over-head florescent lights, you have two options; (1) wear tinted glasses (only helps with spectrum issues but doesn't help with flicker issues) or (2) quit. It doesn't matter how prestigious your employer is or how much they pay you; nothing they can offer you is worth harming your eyesight through continued eye strain. Eye Testing It sucks to admit that you might be getting old, but more often than not vision deteriorates with age. Going to a good eye doctor to get your eyes tested is a REALLY good idea. You probably want to avoid the cheap mall-based eye stores that sell glasses. You'd be better off finding someone who actually knows what they're doing, like getting a reputable eye surgeon in your area to do the testing. It will be more expensive, but well worth it. If you are told that you need glasses, get them, but also look into eye exercises. It is not uncommon to fix mild vision deficiencies through various forms of exercise to strengthen the muscles you use to focus. Also be aware that compensating for weak muscles by using glasses can lead to weaker muscles and the problem getting worse. Eye exercises are seldom an answer, but it's worth looking into, if you pardon the pun. Lastly, if you need help with configuring software, my email address is in my HN profile 'about' section.