I have been wearing eyeglasses since I was seven or eight years old. In all that time I have been lucky enough to have only had significant problems two or three times. Considering all that can go wrong, I am fortunate.
Let me first explain that my eyesight is very poor. My eye doctor told me that my uncorrected vision is somewhere around 20/400, which means that what a person with 20/20 vision can make out at 400 feet, I need to be at 20 feet to see it as clearly.
That "20/400" is what eye professionals would call the Snellen range and it is absolutely an approximation, but it does have some value in understanding just how badly someone sees. I could tell you my prescription instead (OD -2.50 -2.25 097 +2.25, OS -4.50 -2.25 090 +2.25) but that isn't quite as graphic, is it? It's easier to look at at a road sign four hundred feet away and imagine someone needing to be twenty feet from it to read it clearly.
There are charts you can find that supposedly convert your prescription to a Snellen value, but they vary widely. Apparently there is no direct conversion, so take all that as approximations.
None of it matters much. Presumably your eye doctor will do a careful and professional exam and the prescription developed from that will be right for your vision.
Making the lenses
This is the first place that things can go wrong. As you'd imagine, computers play a large role in that process today, but human beings are still involved in lens making, and human beings can make mistakes.
This has only happened to me twice. Because of what I experienced, I suspect that other folks may have had similar problems and may not have known enough to complain effectively.
My original eye doctor only did exams - he worked out of an office in his home and he'd give you the prescription that you'd fill elsewhere. His son took over the business later and expanded to a storefront in partnership with someone who sold frames and did the lens making. You could still take your prescription elsewhere, but it was convenient to have it all done there.
I had purchased glasses there once before and when it came time to replace those, of course I went there again. When I arrived to pick up that latest set, I had quite a shock when I first put them on.
I mean "shock" literally. It felt like my eyes were being forced to cross. I was disorientated and slightly nauseous. The feeling passed quickly, but it was marked enough that I took the glasses off for a moment and then tried them again. I got the same reaction - it felt like my eyes were being forced to cross against my will and I didn't like it.
I told the optician this and he said that I just needed to "adjust" to them. They were progressive lenses, he explained, and that sight disorientation was normal.
I was not convinced. I had been wearing progressive lenses for some number of years by then and was well aware of that initial disorientation, but I had stopped experiencing that years ago. I said as much to the optician and he countered that my prescription had changed and, again, I just needed to get used to it.
Well, my prescription hadn't changed very much, so I didn't think that could be right, but I went along with it. After several weeks with no "adjustment" happening, I went back to complain again. Again, my discomfort was pushed away with "You'll get used to it" and I left unhappy and dissatisfied. I put up with the the morning shock for a few more weeks and then made an appointment with the doctor who provided the prescription.
I explained the symptoms as best I could and he gave me another quick exam to see if perhaps he had munged the prescription. Then he did some more tests with me wearing the lenses and finally went off to do some measurements or tests with just the glasses. When those were done, he told me what he had found: the lenses were made incorrectly.
He said he'd have a private conversation with the optician and a few days later that man called me to pick up a new pair. These were perfect and did not cause any "cross eyed" effect when I put them on. The optician apologized and I was happy.
However, imagine if I were not stubborn about this. If I had not known from my own previous experience that something was wrong, I might have let that optician bully me into accepting a badly made pair of glasses.
If you think something is wrong with your glasses or contact lenses, fuss about it. Get a second opinion or even a third if you have to. Don't let a technician's mistake affect your comfort.
I didn't want to use that optician when it came time for yet another pair. I still went to my eye doctor, but that time I decided to go the discount route and went to Walmart to fill the prescription. The price was less than half of what I was accustomed to paying, so I was initially very pleased.
Imagine how I felt when that new pair gave me a milder form of the same symptoms I had experienced five years earlier at that optician! Not only that, but the frame was obviously low quality (yes, I should have noticed that when I selected it).
I didn't even give them a chance to rectify it - I was angry and demanded a refund, which they gave without argument. I took the prescription to a chain outlet with much higher prices and got perfect lenses made for a far better quality frame. I was happy for another decade or more.
The frames
Until my most recent pair of glasses, I have never had a problem with the fit of frames. My wife says that's because I'm somewhat clueless. She notes that I have endured wounds and not been aware of them until she notices blood staining my clothing. That's true, but those cuts and scrapes came while my mind was focused on building or destroying something. I'd notice a problem with my eyeglass frames; I had simply never experienced any difficulty.
Because of my great luck in that area, I was blissfully unaware of how much can go wrong. I certainly knew that frame quality matters, but I did not know about other factors - and there may still be more that I don't know now!
Pantoscopic tilt
 |
| Old glasses vs. new: pantoscopic tilt |
Look at the photo to the right. These show my previous pair of glasses beside the pair I acquired just recently. I think you can see that the leftmost pair is tilted more than the other pair. That left pair is the pair I have worn for the past six years.
That tilt matters a lot with progressive lenses. The idea with these is that the lower part of the lens is for close up work (reading, for example), the middle is for mid range tasks (watching TV) and the top is for distance (driving, for example). Adjusting your focus becomes largely a matter of tilting your head an appropriate amount.
However, the more the top of the lens tilts forward, away from your face, the more distance correction you get without tilting. Therefore, if your prescription is correct but the tilt is not right, you won't see well at some middle distances. Watching TV might require you to tilt your head slightly for full focus or you might find that you can't quite read road signs as soon as you would like.
If the tilt on a new pair of glasses is substantially different than the old, you'll probably experience that. That was the first problem I had with my latest pair. The optician adjusted them to increase the tilt and I was immediately much happier.
Width
I have a big fat head. It's OK, you don't have to be polite, I know it and am not ashamed of it. I assume that its because I have lots of powerful brain cells. Some of my friends have less flattering explanations - I'll stick with my theory, thank you.
Regardless of why, the fact is that it is big. My earpieces need to be spread wide to fit comfortably on my extra large head. Any optician will of course assume that the frames will be going on a normal person's head, so I always need them to spread those earpieces outward.
That's easy, I'm used to that, but you do need to make them notice it if you have an unusual head width - fat or skinny. My experience is that the fitting optician probably won't notice that my ear pieces are too tight until I mention it. Then they'll laugh and agree that yes, I do have a big head.
Don't count on them to notice by themselves.
Comfort
This is where I really had trouble with my latest pair. A very short time after putting them on, I felt extreme discomfort bordering on pain.
I returned to the optician for an adjustment and brought my old pair with me so that I could show her how those fit. She looked everything over, took both pair back into her work area and soon returned to have me test her results.
I did not realize that she had become confused and had handed me back my old pair to try. I left the shop feeling comfortable and happy: the discomfort was gone.
Amazingly, it took me a week to notice my error. It was only when I tried to attach the clip on sunglasses that came with my new glasses that I realized I was wearing the old pair. Somewhat disgusted, I switched to the new pair and within a very few minutes I was uncomfortable again.
Resting on my Cheeks
 |
| Frame resting on my cheek |
It may be a little hard to see in this photo, but my old eyeglasses actually had contact with my cheeks.
According to everything I have read so far, that's not a proper fit, but it does have the advantage of taking some pressure off your nose.
The pressure is not insignificant for those of us with poor eyesight who require thicker lenses. Plastic lenses are much lighter than glass, but the weight is important.
Interestingly, I expected my new glasses to weigh less than my old because they are slightly smaller. However, a postage scale registers 0.8 ounce for the new pair and only 0.6 ounce for the old. Combine that difference with no longer supporting any of it with my cheeks makes it more than enough to notice.
If you are getting new glasses, be concerned about weight. I never even thought that this new pair could possibly weigh more, but they do. The reason is that the ear pieces and the lense frame are thicker on the new pair. Stronger, probably, but they weight more.
Nose pads
At least part of my discomfort was from the nose pads. The new pair had heavier and harder pads. I'm not entirely sure why that should be the default; my old pair had soft, almost gel-like nose pads. I would have expected that everyone would prefer the more soft nose pads, but apparently they do not or do not notice.
When I returned for another adjustment, the optician changed the pads to the softer versions. That made an immediate comfort difference, though I am still not sure that I am entirely comfortable. I'll give it a week or so to adjust and see what I feel like then.
Don't be bullied
My optician is not being difficult about this at all. In fact, she wanted me to stay longer on my last visit to see if more adjustments might become apparent in fifteen minutes or so of use. I was the one who decided that I ought to give myself a longer time to adjust; I think that the difficulties I have already experienced may be coloring my perception and causing me to interpet mere difference as true discomfort.
However, as you will remember from my "cross-eyed" experience, not all opticians will be so ready to accept your opinions. I can't stress this strongly enough, and especially to those who have not had long years of eyeglass experience: if you think something is wrong, speak up and don't let yourself be talked into acceptance. Your vision and comfort are very important!
0 comments:
Post a Comment