Forum Home
PC World Chat
Thread ID: 97749	2009-02-26 06:27:00	Prisms in glasses	somebody (208)	PC World Chat

Post ID	Timestamp	Content	User
751509	2009-02-26 20:49:00	I always thought he prisms were to correct an astigmatism. But probably not. I used to havethe old cokebottle styled classes up until the late 90's, these has prisms to force my eyes to work together. As I understood it, they could put weights in contacts to correct a lens misshape, but you lost the benefits of prisms by moving to contacts (talking disposable ones). As that wasn't a technology available in contact lenses. At the same time as getting the new contacts I got a new pair of glasses, without prisms. Seems that my eyes had corrected themselves, got stronger, however you want to put it. The optometrist called the "weight" in my left contact lens "a prism" and it was certainly a prism shape. I never used disposables; you are right - in those days anyway you couldn't buy disposables that corrected for astigmatism. In my case, the prism was for astigmatism, not a lazy eye, and it worked very well.	John H (8)
751510	2009-02-26 20:51:00	Or do nothing and end up looking like this :D : I think that dear old Marty's eyes are a result of a thyroid problem, not the issue raised by somebody.	John H (8)
751511	2009-02-28 01:38:00	Hi Somebody, I'm an optometrist. From what you've described, you've only got a minor tendency to deviate (exophoria / esophoria or hyperphoria). This definitely does NOT warrant any surgery, and is not in the scale of the Marty Feldman type issues that others have talked about. The prism is primarily just to relieve a little muscular strain, and in so doing give better comfort, and less fatigue. The actual clarity of your vision is unlikely to be improved, and your lenses may end up looking a little bit thicker on one edge as a result of the prism. Prism in small amounts can be achieved by: a) decentration of your lenses (if they are strong enough, but within 'stock' range). This costs no extra, but lots of support staff fail to grasp the concept of how to order this without incurring extra costs or b) grinding prism onto 'specially worked' lenses. Typically about $100 dearer than the 'stock' lens option. If you are outside the usual 'stock lens' powers, the prism will barely cost you any more than normal. I wear prism myself. Wouldn't go without it. Forget prism in contacts - the prism others have discussed is called 'prism ballast', and it's there as a weight to stabilize a type of contact lens which has a spread of two different powers (toric lenses for astigmatism). It is no good as a prismatic optical correction, and in 20+ years of work I've never attempted optical prism in contacts, and don't want to - very high cost, poor comfort, little choice of manufacturers. Surgery on SMALL deviations will only make it worse. It's a hit-and-miss proceedure aimed often for a cosmetic rather than functional improvement, and only for significantly large problems of allignment.	Paul.Cov (425)
751512	2009-02-28 01:48:00	Hi Somebody, I'm an optometrist. From what you've described, you've only got a minor tendency to deviate (exophoria / esophoria or hyperphoria). This definitely does NOT warrant any surgery, and is not in the scale of the Marty Feldman type issues that others have talked about. The prism is primarily just to relieve a little muscular strain, and in so doing give better comfort, and less fatigue. The actual clarity of your vision is unlikely to be improved, and your lenses may end up looking a little bit thicker on one edge as a result of the prism. Prism in small amounts can be achieved by: a) decentration of your lenses (if they are strong enough, but within 'stock' range). This costs no extra, but lots of support staff fail to grasp the concept of how to order this without incurring extra costs or b) grinding prism onto 'specially worked' lenses. Typically about $100 dearer than the 'stock' lens option. If you are outside the usual 'stock lens' powers, the prism will barely cost you any more than normal. I wear prism myself. Wouldn't go without it. Forget prism in contacts - the prism others have discussed is called 'prism ballast', and it's there as a weight to stabilize a type of contact lens which has a spread of two different powers (toric lenses for astigmatism). It is no good as a prismatic optical correction, and in 20+ years of work I've never attempted optical prism in contacts, and don't want to - very high cost, poor comfort, little choice of manufacturers. Surgery on SMALL deviations will only make it worse. It's a hit-and-miss proceedure aimed often for a cosmetic rather than functional improvement, and only for significantly large problems of allignment. Thanks for your explanation - it all makes a lot more sense to me now. My lenses are typically towards the more expensive end of the spectrum (-4.25 and -4.75 if I recall correctly, with a fair bit of astigmatism correction). I think the last time I had them replaced the cost was around $400-500 so I'm not sure whether they were stock or not. I have another appointment with my optometrist this week, so will see how things go.	somebody (208)
751513	2009-02-28 04:17:00	[QUOTE=prefect;759512]Yeah I had a female flatmate like that whose eyes looked like they were looking at you but weren't when she took her coke bottle bottom glasses off./QUOTE] Must have been a long time ago, "bottle bottom" glasses are long out of date. I too have seriously "unbalanced" eyes and one lense used to be so thick and heavy that my glasses always sat lop-sided on my face, but ever since they introduced high refractive index glass thel lenses are very similar in weight and thickness so it is hard to see the difference between them, and with similar plastic lenses as per my current glasses they are so light-weight I hardly know they are there. I also have independent monocular vision (on demand) so I can look in two different directions at once. It is a bit confusing for the brain, but you get used to it and can switch eyes whenever you want. It scared my kids no-end when I could watch both at once in two different places in the room. Cheers Billy 8-{)	Billy T (70)
751514	2009-03-01 23:06:00	Having had seven reconstructive eye surgeries on my right eye and three on my left, I too require prisms to relieve "torquing" of my right eye . It all started with cataracts in both eyes, although the left was a little behind the right in advent of surgical intervention . The left developed a cataract, I was implanted and developed envelope problems and needed argon laser treatments to remove the opaque tissue without surgery . The left eye was later also operated on and I was seeing 20/40 Left, 20/15 Right . Pretty good! Two years later I developed "lizards with red and blue electric flames" running across my vision while driving at night . The reflectors on the lane markers would reflect the headlights back to me and I saw lines of little lizards running off to the right side of the road and disappearing into the ditch by the thousands! It was a detached retina . Retinal reattachment surgery was done and I lost a lot of peripheral vision in that eye . Several more times I had to have the retina reattached, each time losing some more retina and getting closer to just the macula left for vision in that eye . The left eye, in the meantime had been refracted incorrectly and I complained about it quite a few times . What had happened was that they used a Doppler refraction testing machine and it indicated off a "bulge" on the retina and they adjusted the implant to the results . That bulge panicked the doctors who thought I was experiencing an aneurysm in a blood vessel behind the retina . Back onto the slit scope and they found that my blood vessels in the eye were counter-rotated, or entered in the wrong position and they had measured my eye for the lens prescription on top of that bulge . With the history of detachment in the other eye, the docs decided to NOT replace the implant with the correct one since the pressure loss MIGHT be a catalyst to the retina detaching in this eye too . A piggy-back lens was opted for and that was successfully implanted . The resulting surgeries and physical abuse to my eyes caused a form of "torquing" since the eye muscles had been somewhat stretched and misaligned and I needed prisms to help with the surgically-induced strabismus . Thankfully I don't have to pay for them as the need for the prisms was caused by inaccurate refractive mistakes . I am kinda surprised that the eye-professional didn't pick up on somebody's statement of IT work damaging eyes . Posted by somebody: I already have very bad short sightedness, and some fairly significant astigmatism - so working in the IT industry certainly doesn't help . Eyes are not interactive and are instead passive and watching television, reading too close or too far away, working as an IT expert or wearing rubber boots in the house will NOT cause eye disorders . Eyes themselves don't physically tire; the muscles that point, focus and direct them do however .	SurferJoe46 (51)
751515	2009-03-01 23:25:00	<snip> Two years later I developed "lizards with red and blue electric flames" running across my vision while driving at night. The reflectors on the lane markers would reflect the headlights back to me and I saw lines of little lizards running off to the right side of the road and disappearing into the ditch by the thousands! <snip> Some people pay good money for drugs that give that effect Joe!!	johcar (6283)
751516	2009-03-02 02:28:00	Some people pay good money for drugs that give that effect Joe!! I know! My doc thought I was crazy when I told him that, but in the years since, he's had another couple of people see pretty much the same thing . He vows to never doubt the existence of small road-running lizards again . I tell you what, though: that operation for the first retinal reattachment was the most painful post-op pain I've ever felt . I've had crushed bones, everted intestines and smashed pelvis, but THAT was the absolute worst!	SurferJoe46 (51)
751517	2009-03-02 07:26:00	[quote=prefect;759512]Yeah I had a female flatmate like that whose eyes looked like they were looking at you but weren't when she took her coke bottle bottom glasses off./QUOTE] Must have been a long time ago, "bottle bottom" glasses are long out of date. I too have seriously "unbalanced" eyes and one lense used to be so thick and heavy that my glasses always sat lop-sided on my face, but ever since they introduced high refractive index glass thel lenses are very similar in weight and thickness so it is hard to see the difference between them, and with similar plastic lenses as per my current glasses they are so light-weight I hardly know they are there. I also have independent monocular vision (on demand) so I can look in two different directions at once. It is a bit confusing for the brain, but you get used to it and can switch eyes whenever you want. It scared my kids no-end when I could watch both at once in two different places in the room. Cheers Billy 8-{) I find rum has a similar effect sometimes when the bottle is a bit free-draining.:yuck:	R2x1 (4628)
751518	2009-03-23 03:58:00	I thought I'd just give everyone an update on how things went. After getting a quote, I decided to go for the prisms, as I figure it's best in the long run for my health (even though it was quite expensive). The cost came down to a couple of factors: - The lenses had to be specially made, as they weren't a stocked item - The lenses had to be made in the USA, and shipped here On the plus side, the optometrist I went to was exceptionally helpful, had fantastic service, and took the time to answer all of my questions. I would strongly recommend them (Matthews Eyewear/Eyecare) to anyone in the Wellington region who needs glasses.	somebody (208)
1 2 3