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Medical Forum / General / Vision / September 2005Tangent Streak Trifocal update
[I lost the other thread] Not sure how this happened but the consultant from Fused Kontacts somehow convinced my doc that the trifocals would not be a good idea and to try the aspheric ones. They centered perfectly and distance vision was really great. Unfortunately there was virtually no add. It was so bad that my doc doubled checked the lenses to be sure they sent the right ones. A little questioning and he said the consultant hadn't told him the size of the centers or the size to the full add. He said he didn't know if that was because the consultant just didn't know or if it varied by prescription or what... I urged him to switch consultants. He said he'd order the trifocals or maybe the bifocals for an initial fit followed by the trifocals. One potential problem? was that my lower lids didn't seem to effect any translation at all when looking down. When I blink I can see the lenses translate upward pulled by my upper eye lids (they go up and drop right back down). We did the camera thing and looking down the lens stays pretty much perfectly centered over the pupil and looks to be about 1/3 covered with my lower eyelid. I told him if big prisms with truncation didn't work maybe they could attach little handles to the bottoms. I'm really hoping because the distance clarity was remarkable. -Quick I should add that my pupils are right at 3.5 mm. For the lower eyelid thing he said these were pretty thick lenses and some translation could be expected. (~+1.00 with ~+2.00 add?). -Quick > [I lost the other thread] > [quoted text clipped - 5 lines] > It was so bad that my doc doubled checked the lenses > to be sure they sent the right ones. Well, I think if they are aspheric, they are not translating, and have no discrete near area that can be "double checked". A little questioning > and he said the consultant hadn't told him the size of > the centers or the size to the full add. He said he didn't > know if that was because the consultant just didn't > know or if it varied by prescription or what... I urged > him to switch consultants. The aspherics are voodoo optics, and have no definable near zone. > He said he'd order the trifocals or maybe the bifocals > for an initial fit followed by the trifocals. Seems reasonable. > One potential problem? was that my lower lids didn't > seem to effect any translation at all when looking down. The aspherics don't translate at all, and aren't supposed to. > When I blink I can see the lenses translate upward pulled > by my upper eye lids (they go up and drop right back down). > We did the camera thing and looking down the lens > stays pretty much perfectly centered over the pupil > and looks to be about 1/3 covered with my lower > eyelid. Ibid. I told him if big prisms with truncation didn't > work maybe they could attach little handles to the > bottoms. The prisms will work. The lined bifocals *will* have prisms, unlike your aspherics. > I'm really hoping because the distance clarity was > remarkable. It should be good, but maybe not quite as good, as you may well get a bit of interference from the line(s) that you don't now have... w.stacy, o.d. >> They centered perfectly and distance vision was >> really great. Unfortunately there was virtually no add. [quoted text clipped - 4 lines] > translating, and have no discrete near area that can be > "double checked". Well, I think he doubled checked whatever it was they came in to be sure they had the add on the label. This might explain why the consultant couldn't give a center optical size though. That's a bit reassuring. >> One potential problem? was that my lower lids didn't >> seem to effect any translation at all when looking down. > > The aspherics don't translate at all, and aren't supposed > to. He seemed to be expecting just a bit of translation due to my lower lids when looking down. You wouldn't expect any at all? > The prisms will work. The lined bifocals *will* have > prisms, unlike your aspherics. Not mine any more. We just tried them and I left with the Cooper vision softies I've been wearing for a few weeks now. Distance center in dominant eye and near center in other. A modified monovision I guess. It works but I don't like the compromises. Blurry when looking left etc. If all else fails they're acceptable and better than reader spectacles. He didn't have the 55s in stock last time I lost one and he gave me the proclear version. I think they're clearer but don't compare with the Tangent Streak RGP's clarity. The vision through the RGPs really meets my expectations (which is basically no compromise) which is very encouraging after all the compromise admonishions from the first doc when I couldn't really see. >> I'm really hoping because the distance clarity was >> remarkable. > It should be good, but maybe not quite as good, as you > may well get a bit of interference from the line(s) that > you don't now have... I'm hoping my smaller pupils 3.5 mm will minimize this and with a bit of head positioning adaptation should be a non issue. So is there anywhere that makes "money no object" totally custom segmented lenses? What if I like the trifocals but want the intermediate segment wider, making the bottom segment smaller? No, I'm not a "money is no object" guy but I could go 3 or 4 times what most are willing to pay. -Quick > So is there anywhere that makes "money no object" totally > custom segmented lenses? What if I like the trifocals but > want the intermediate segment wider, making the bottom > segment smaller? Tangent Streak by Fused is the only one I know of. I think they made a mistake introducing a non-translating aspheric under the same brand. Just confuses the issue. Tangent Streak describes pretty well the line that is actually just like an Executive spectacle bifocal, where the two different curvatures are tangential with one another at the center of the "streak" or line. The aspherics have no streaks or lines to be tangential at all. Anyway, no, unless Fused makes it, I don't think it exists. They might consider a wider intermediate seg and have probably experimentally tried it. I can't think of a reason it isn't technically feasable. w.stacy, o.d. >> So is there anywhere that makes "money no object" totally >> custom segmented lenses? What if I like the trifocals >> but want the intermediate segment wider, making the >> bottom segment smaller? > Anyway, no, unless Fused makes it, I don't think it > exists. They might consider a wider intermediate seg and > have probably experimentally tried it. I can't think of a > reason it isn't technically feasable. I need to make friends with someone in manufacturing... -Quick > Tangent Streak by Fused is the only one I know of. I think they made a > mistake introducing a non-translating aspheric under the same brand. [quoted text clipped - 7 lines] > consider a wider intermediate seg and have probably experimentally tried > it. I can't think of a reason it isn't technically feasable. They addressed your confusion by calling the lenses Tangent Steak Bifocal, Tangent Steak Trifocal and Tangent Streak No-Line. (I use a lot of the latter, including using it myself.) The concept of a translating aspheric is out there as is translating segmented with aspheric progressive distance to midrange, and aspheric from distance through the near seg. Presbylite, a Gelflex version, and Llevations (cool name!) are examples. I've tried (although a few years back and there have been design changes since, so this is FWIW) the former two. The Gelflex was an awesome lens in terms of optics but the comfort, owing to the prism base and edge contour, blew it for me. I really like the idea of that lens (and combining aspheric and segmented optics!) and perhaps someone who has had more experience with it might comment on recent versions. --LB, O.D. I've had my first set for a bit over a week now. We need to do some adjusting. I've included observations made after 3 days that I sent to my doc with comments following my subsequent visit (subsequent comments in []). (Did I say that I'm so glad I found a great doc to work with?) =================================================== I'm feeling really good about these! I'm confident this will be the end solution. General: I think there is something wrong with the right lens. More than just the orientation. In particular with the center segment. It seems noticeably "cloudy" as if it was made of a different material or maybe not polished to the extent of the other two segments? The left lens seems to have just the slightest bit of this also. It's virtually not noticeable on the left lens. Comfort improves every day and it was not real bad to start with. I think the left lens may fit better than the right. I can feel the right lens more and my right eye gradually get more open as the day progresses. I sort of end up with an "evil eye" look after some time. [It's lid discomfort. They are thick lenses and at this diameter my eye lid is right at the top edge when open. Doc figured it's sort of "bumping" over the edge on blink. We're going to try a larger diameter which should address a couple of other issues as well.] Things seem to get a bit dry after a while. A couple of times I've had one come out when making an unusual eye movement when they were dry. Change in curve? [Doc thinks they may be a bit tight. Right lens is rotated nasally about 10 to 20 degrees and left rotates nasally on blink. (these are truncated). Larger diameter. (maybe flatter too?)] Centration: Both seem to be centered about the same. Not bad but I can see the outer edges of both lenses. About 1/4 of the circumference is visible in my peripheral vision when looking straight ahead. Especially in daylight this gives some effect of looking through a viewer. I have never seen the inside edge of either lens. Can we move them? What are the tradeoffs of a larger diameter? At times there is a noticeable edge effect. (I suppose the edges are polished?) This can be very pronounced while night driving with headlight reflection from the right side mirror. [They are actually centered pretty well over the pupil and slightly inferior <- heh, technical term... hopefully it means slightly below center. Try larger diameter] Unless they are extremely wet the lenses take about 1 second to recover from blink translation. The right lens has a tendency to take longer than the left as they get drier. The translation appears to be straight up and down. What are the tradeoffs of thinning the top edge? [Fit may be tight. Larger diameter would give a looser fit and put the top edge under my upper eye lid. Being under my upper eye lid should decrease the interaction of the eye lid on blink? I guess a looser fit would result in a quicker recovery from blink translation?] The right lens appears to be rotated 10 to 20 degrees? The left lens just slightly. Refraction: Distance vision is simply outstanding! The clarity is astonishing.. The intermediate segment is hard to make a judgment on due to the right lens orientation. Left and Right segments translate at different points and the right translates diagonally across my pupil. I think we are in the ball park though. Maybe a slight increase in power? maybe not. The text on my main monitor is about 2 mm high and I'm about 27 to 30 inches away. Near is again a bit difficult to gauge but I think it's right on (to judge the right eye I have to look down and left at the end of my nose which doesn't leave much of a window for the text. [Unusual (nice) feature of the Tangent Streak trifocals is that you can specify the add for the middle and lower segment independently of each other.] How much experimentation do we get? I guess fit and orientation first followed by power adjustment of the intermediate segment if necessary. [We're probably going larger and different material. These are Hydro2. He ordered them in green for right and blue for left. Says he likes that better than the dots that wear off. He prefers the other material we're going to (forgot the name...) for the higher DK and he feels better wetting). They (he and the consultant) went with the hydro2 because I guess the tint is darker with the other and they thought it would visibly change the color of my eye. My response: I'm too old, I ONLY care about what it looks like from my side.] If possible I would like to experiment with widening the center segment a small amount. I would do this by leaving the lower segment height where it is and raising the top segment. I'm willing to trade a bit of night time flare for less of a down gaze in front of the PC. [Bummer. Middle segment width is not changeable. I think we're going to try to raise the top segment a bit. My pupil is about 3 mm in office light and about 5 mm in low light. Right now the left segment appears to be sitting about 1 mm below the bottom edge of the pupil in office lighting. I'm not getting any flare while driving at night. I was guessing I could raise it about 0.5 mm to lessen down gaze at the PC and incur minimal, if any, flare at night?] So I'm really pleased so far. I was beginning to have doubts in the modified- monovision softies. I wish I could increase the middle segment while decreasing the bottom segment but oh well... My 20" CRT sits about 32" in front of my face and I get maybe 1/3 the height of the screen through the middle segment. Did I say I'm really glad I found a great doc to work with? -Quick
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