Originally Answered: Is 20-30 vision good? What do those numbers mean?
It isn't *good* -- but it is acceptable. It is acceptable for an eye exam to drive a motor vehicle, and generally an acceptable outcome even after eye surgery of all types.
Most people think 'perfect' vision is 20/20 -- when in reality the human eye should see closer to 20/15 -- The 20/20 standard is just more a mean average of 'best correction' over an average of people.
More times than not corrected vision, especially in at least one eye is 20/15 (now better than this is rare.. but not unheard of.)
Also the 20/20 -- 20/30, 20/40 and so on measurements are just one aspect of your vision.
When someone asks how our vision is we generally refer to these measurements which are simply our visual acuity on the snellen eye chart.
Vision is much more than acuity alone. There are many people who can see 20/20 or even 20/15, but have terrible vision due to light sensitivity, glare, contrast problems, cornea disorders,.. and on and on the list goes.
But in general this measurement is a good rule of thumb to try and 'correct' vision against. It is a good measurement in *most* healthy eyes to determine what is or isn't working.
In your case,.. as a guess,.. your vision has probably deteriorated due to a small astigmatism (Basically a subtle difference in the curve of your cornea in relation to the lens) -- This will cause blurring, sometimes ghosting, some subtle variations in contrast sensitivity, color perception, and other qualities of the eye. When all combined make vision less than ideal.
As has been said, many people choose to leave 20/30 vision as is -- there are several reasons:
1) If no major symptoms are present with this measurement.. then correction isn't really indicated. It may forever stabilize at this reading.. or even (rarely) move back to 20/20 (Sometimes some minor corneal swelling, haze, dry eye, allergy, or other condition can cause temporary vision deterioration)
Further on that point.. even severe chronic computer use can push a 20/15 or 20/20 eye to 20/30 -- This is temporary,.. but for an extreme example. If Joe Blow uses his computer 12 hours a day, with little breaks, for 10 years -- he WILL develop some extreme CVS (Computer vision syndrome) which will cause tearing issues, eye strain, muscle strain (iris spams potential),.. focus issues.. and even some minor neural adaptation to the constant focus on something a few feet away that presents 3d imagery on a 2d source. ***Note this is not scientifically proven -- just theories at this juncture so don't go quoting it :) ***
CVS is general is very much proven, and the correlation with prolonged use (such as Joe Blow's case) is becoming more prevalent to cause STILL temporary eyesight problems but problems that takes considerably longer to resolve. IE: Problems that mimic other organic problems because they might take several months to full resolve (with abstinence of the computer).
Again -- so back to your vision:
2) Many leave 20/30 as is because you CAN function with it on most all levels. People don't like glasses, and contacts are a hassle any way you look at them. So they just don't bother.
3) At this minor impairment,.. the money of corrective lenses is a factor.
4) Even some still believe (and I am neutral on this stance.. ) that corrective lenses will 'weaken' the eyes over prolonged use. IE: You are 20/30 -- You correct with lenses to 20/20. In X years.. the eyes adjust to the lenses and without the lenses you are now 20/40.. whereas if you didn't correct you would still be 20/30. This is very HARD to prove either way (and if anyone definitively dictates either side is an absolute, be weary of their advice) -- Why? Because if you cannot tell the natural regression of the eye with corrective lenses. In other words.. you cannot tell if the eye would have regressed to 20/40 even if you DIDN'T correct them with lenses.
6) Some want to hold off for laser surgery (do your homework on this.. read peoples stories good AND bad .. I beg of you.) -- It is of my personal opinion (and I've never had surgery on the eyes) that unless you need eye surgery for a major medical condition -- that vision corrected WELL with glasses should NOT be altered/or messed with. In other words,.. don't fix something that isn't broken.
I know it seems awesome to think you can get rid of your glasses -- but there are soooo many unhappy post lasik patients.. and some minor percentage that have worse vision after surgery -- Further a percentage that have their lasik correction 'wear off' for lack of a better term.. after so many years that the *potential* risk , imho, FAR outweighs the good.
If you can happily see very clearly with glasses -- live with any insecurty about 'frames' -- there are so many options with eye glass frames and they are so common. (I find many people look better with glasses.. really.) But if you decide to go this way one day,.. do your homework on the internet,