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Medical Forum / General / Vision / November 2007new glasses adjustment period
Hi, I recently got new glasses (basically new frames, but same prescription) after wearing my old ones for 3 years. Anyway, I know there's always an adjustment period, but I've never experienced like this one before (or maybe its been a while so I don't remember). The experience I"m getting is that the ground look closer than they normally appear, but the biggest nuisance is that objects that ought to be square look like "trapezoids" (the sides are slanted inward). This is annoying since I work on the computer a lot and my flat screen looks like a trapezoid (not pronounced trapezoid, but I can tell the difference) and the sides of the document are slanted inward. Does anyone know if this is normal? I called my optometrist and they suggested to wait a couple of days for my eyes to adjust and if it still happens again to come visit them. But I'm not sure if I'm just being paranoid or being overly concerned. Has anyone experienced this? Thanks. Avalon >Hi, > [quoted text clipped - 13 lines] >being paranoid or being overly concerned. Has anyone experienced >this? Thanks. There are a number of distortions introduced by glasses. What you describe as a trapezoid sounds actually like pincushion distortion (the reverse is barrel distortion). Another effect is minification, where objects look smaller than they actually are. When your prescription changes, the nature of these distortions change, and it takes getting used to. Without knowing the old and new prescriptions, however, one can only speculate precisely what differences you should expect.  Signature- Mike Ignore the Python in me to send e-mail. Dear Avalon, Do you have your prescription? Why not post it? Best, Otis > Hi, > [quoted text clipped - 15 lines] > > Avalon My prescription hasn't changed (-1.25 on both eyes). I don't wear glasses often and I switch between contacts and glasses. My old glasses (again at -1.25 prescription on both eyes) are 3 years old. The shape of the frame is somewhat rectangular but the corners are curved so its not like a perfect rectangle My new glasses is more rectangular, and although the corners are still curved, it is a sharp curve so it does look more squarish than my old glasses. I'm thinking the trapezoid effect is due to the frames because the top part of the glasses is wider than that of the bottom, but regardless, that shouldn't have a profound effect of making all squares look like trapezoid, doesn't it? I dunno. If I can find the model number of my new frames, I'll post it here, but the type is JhaneBarnes. The lenses are antireflective, polycarbonate, and photochromic. The profound trapezoid effects is very obvious if I look at squarish objects real close (like my monitor), but if I look at, say, the door from the distance, it looks fine. Also, the ground looks much closer to me than if I wear my old glasses (basically I feel shorter). I hope these information helps. I'm trying to see if my eyes will adjust, but since I work on computer a lot, the trapezoid effect gets really annoying (basically my monitor looks wider from the top and narrow at the bottom) Avalon On Oct 31, 1:14 pm, "otisbr...@pa.net" <otisbr...@pa.net> wrote: > Dear Avalon, > [quoted text clipped - 27 lines] > > - Show quoted text - > My prescription hasn't changed (-1.25 on both eyes). > [quoted text clipped - 25 lines] > > Avalon Even before your second post above, I was about to say that you have probably been f***ed by polycarb, the worst optical material that is commonly dispensed. > Even before your second post above, I was about to say that you have > probably been f***ed by polycarb, the worst optical material that is > commonly dispensed. Polycarb causes trapezoids? Barrel distortion is greater with poly? How do you explain yourself? Poly shows some color separation in higher prescriptions. Besides that, what's wrong with polycarb? Why do you trash it over and over? Is it because your competitors sell it? Is it because it's safer than CR39? I've had polycarb glasses for a couple of decades and never noticed trapezoids. The OP was f***ed by the optician who increased his base curve or raised the vertical centers. -MT You know what, I was thinking about it too, but I always thought that as an upgrade from my previous lenses. But I have to say that that is one main difference between my old and new. Does polycarbonate really add that effect in the lenses? (the trapezoidal effect and the ground looking closer?) I was told its better because it makes the lenses lighter and that is one reason I chose it because my previous lenses are heavy in a sense that it adds pressure to my sinus. But I dunno..... What do you guys suggest? Alright so I take it its not the polycarbonate effect then (based on Mike Tyner's input) and from the sound of it its not the effect of the adjustment period. Should I just go ahead and have it looked at instead of waiting for a day or two to keep my eyes...well...adjusting? Its probably not caused by the frame or the prescription then but its most likely how they shaped the actual lens themselves? > Alright so I take it its not the polycarbonate effect then (based on > Mike Tyner's input) and from the sound of it its not the effect of the [quoted text clipped - 3 lines] > prescription then but its most likely how they shaped the actual lens > themselves? if your prescription is -1.25 sphere in both eyes, its hard to conceive of a change in material to polycarb causing the kind of distortion you are describing. if your prescription is unchanged, then most likely the optical centers of your new glasses are improperly aligned with your pupils, or the base curve of one or both of the new lenses has changed over what you are used to, or the prescription used to make the glasses is simply wrong. all of these possibilities are simply checked by visiting your eye doc's office, or your optician's shop if they are not the same, and having those possibilities checked out. simply bring in your pair of "good" glasses versus the new "bad" glasses and have these parameters checked out. > eyes...well...adjusting? Its probably not caused by the frame or the > prescription then but its most likely how they shaped the actual lens > themselves? It's certainly not the material. Nor did they necessarily do wrong, just different. Trapezoids come from distortion that is present in all minus lenses. The effect varies with vertical position and with base curve, as p. clark said. It also varies with the distance between your eye and the lens. Often it can be reduced by tilting or wrapping or otherwise adjusting the frame so the lenses fit closer to your eye. -MT > You know what, I was thinking about it too, but I always thought that > as an upgrade from my previous lenses. But I have to say that that is [quoted text clipped - 6 lines] > > What do you guys suggest? A lot of people claim that polycarb is not a problem, especially at low powers. But if the lens is aspheric and polycarb, I think they are wrong. Polycarb is lighter than regular 1.50 plastic, but so are a lot of other materials. If you can find a transitions lens that at least 1.53 index and not polycarb, then I would go for it. Specifically, I would recommend the following: HOYA Phoenix (Trivex) Transitions V (1.53 index) Spherical, and about the same as polycarb in terms of tensile strength and impact resistance.. Trivex is an excellent lightweight material. Transitions V is the latest version of Transitions. This is probably the best choice for you. Essilor SFSV Spherical Thin&Lite Transitions (1.6 index) Good choice if you want spherical. Thin and light because of higher index, but not quite as strong as Trivex or polycarb if safety lenses are required. SOLA ASL Spectralite Velocity (1.54 index and aspheric). Good lightweight material. This is probably a little cheaper than the above but is aspheric. With your mild Rx , you don't need an aspheric lens, and you might find that distortions are less with a spherical lens. >Hi, > [quoted text clipped - 15 lines] > >Avalon I don't know how you can get this type of distortion in a single vision -1.50 lens unless the lens is warped. Lens warpage is not uncommon in lower powers and thin centers, combined with narrow frames and lens materials that tend to flex easily. Take the eyeglasses back immediately and have the lens checked for waves and warps. While your there, ask to have the panto increased and move the lenses down and in towards the eyes, if not done so already. Hope this helps, Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "Science is a way of trying not to fool yourself." - Richard Feynman Thanks for all the reply and help, but this morning I went back to my optometrist and here's the diagnosis: - even though my prescription hasn't changed (-1.25), there is a change in my eye such that my eye (I dont remember if one of the eyes or both eyes) has gotten more astigmatism (my eyes hasn't always been a perfect sphere to begin with, but I guess this time its gotten more...well...flatter I guess), and some number called the axis changed from 0 degress to 20 degrees. - doc says the change was significant enough to see that noticeable change. Note that the last time I had my lenses changed was 3 years ago - recommendation is to wait a week to see if the trapezoidal effect will correct itself such that by the end of the week everything would look normal again (my screen can finally look straight). Its ok to switch with my old glasses if I get really annoyed (like every couple hours or so) until my eyes adjust. - if by the end of the week, the world is still a trapezoid, then they can check the refraction on my eyes again to verify the numbers are correct and readjust the lenses. So I guess what this means is for at least a week I have to get used to my screen looking like a trapezoid and hope that it'll correct itself within a week. Wish me luck! :) >Thanks for all the reply and help, but this morning I went back to my >optometrist and here's the diagnosis: [quoted text clipped - 5 lines] >more...well...flatter I guess), and some number called the axis >changed from 0 degress to 20 degrees. Your Rx has changed. >- doc says the change was significant enough to see that noticeable >change. Note that the last time I had my lenses changed was 3 years [quoted text clipped - 15 lines] > >Wish me luck! :) I still don't see how you can get a trapezoid .../ \...appearance even with the introduction of an astigmatism component. I would expect responses like the screen looks taller, wider, or if an oblique axis, a parallelogram.../ / or \ \. Interesting. Progressives can certainly cause a trapezoid shape to the monitor if the lens is set to high and away from the eyes. Regardless, unless the doc changed your Rx from a .25DC to a 2.75DC and/or a significant axis change, your brain, in most cases, will compensate within two to ten days. Good luck. Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "Science is a way of trying not to fool yourself." - Richard Feynman > I still don't see how you can get a trapezoid .../ \...appearance even with the > introduction of an astigmatism component. I would expect responses like the > screen looks taller, wider, or if an oblique axis, a parallelogram.../ / or \ \. > Interesting. Actually its more like \ / than / \ appearance. This is what I see if I look straight ahead to my monitor. But if I shift my focus, by moving my body to the left and looking straight ahead, the monitor looks / /. Vice versa if I shift my focus to the right. But yeah, looking straight at the monitor, the monitor looks \ / My doc tells me a 20 degree axis change is pretty significant. I just hope after a week the sides of my monitor can look straight again. > Progressives can certainly cause a trapezoid shape to the monitor if the lens is > set to high and away from the eyes. [quoted text clipped - 15 lines] > > - Show quoted text - > Thanks for all the reply and help, but this morning I went back to my > optometrist and here's the diagnosis: [quoted text clipped - 25 lines] > > Wish me luck! :) If the optical shop offers a full refund, invoke that right now and go elsewhere with one of the lenses I mentioned in an earlier post. There is no way you should need an adjustment period for a -1.50 SV lens, even if it changed from your previous Rx. |
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