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Medical Forum / General / Vision / August 2005Purevision vs. Focus Night & Day?
I posted the following a couple days ago, but I don't see it in my newsreader, so I think it may not have actually posted. Therefore, I'll repost it. If you see it twice, sorry. ---------------------------------------- Now that Purevision is available once more in the USA, one wonders how these two 30 day-approved silicon hydrogel lenses compare. I think it would be interesting to hear from eye doctors who have prescribed both, and from patients who have tried both, to hear how they compare. Not along the lines of "which is better", because I'm sure the answer to that one would be "depends on the patient". One might be better for some patients, the other for other patients, etc. However, it could be discussed which might be better for certain conditions. For instance, for patients with dry eyes, which of the two seems to give better results? For patients with astigmatism? Also, both are aspheric, which I understand means they provide a little presbyopic correction, even without being multifocal, and even if not prescribed with monovision. (I'm currently wearing N&D monovision.) Does one of these two provide better inherent (not considering monovision) presbyopic correction than the other? Anyone know if either company plans to come out with a multifocal silicone hydrogel in the near future? Also--has one of these two lens materials demonstrated more or less problems than the other in extended wear usage? I see the Purevision has some kind of marking so you know for sure that the lens is being put on the right way, not inverted. That is an advantage over the N&D, although minor. Any other features that are better in one than the other? It would be interesting to see all aspects compared . (Once again, not to say "which one is better", but to see which might be more suitable for different patients and conditions.) Thank you for your input. Not only have I prescribed them both, but I have worn them both. IMO, they are not that much different clinically. Personally, I give the edge to Purevision, but others prefer the Focus N&D. One advantage of Focus N&D is availability of two base curves, although I seldom use the 8.6. The Focus N&D also has the higher DK, if you really want to split hairs. The Purevision seems to have the slicker surface, whatever that means. Currently I am wearing the Acuvue Senefilcon (Oasys) and have been for the past month or so. I like it very much. It is really gratifying to know how far contact lenses have come in the past few years...and how much better they might still become. DrG I'm not a doctor, but as a patient, I've tried both. I started with N&D, switched to Purevision when they became available, and now I'm back to N&D. For me, Purevision were more comfortable for the 1st 2 hours of wear, and then the comfort degraded *rapidly* -- by the end of the day, they were pretty much intolerable. I did find that the vision in my left eye was a little bit better with the Purevision (don't know if all BL's claims of better visual acuity are true, but for me there was a slight improvement). In the final analysis, I just found the N&D to be a better lense for me. It's interesting that Dr. Leukoma found the Purevision to be "slicker" - I actually went through a phase of wearing 1 Purevision and 1 N&D in opposite eyes for a couple of weeks, and found the N&D to be significantly "slicker" after the first day of wear. Maybe it has something to do with my eye chemistry and how it reacts with the lenses, but it *seemed* like the N&D surface treatment was *MUCH* better and slicker than Purevision's. As has been said in this forum dozens of times, everyone's eyes are different, and YMMV. Right now, I'm waiting for Oasys to come out (officially) next week, so I can try those. Keith > Not only have I prescribed them both, but I have worn them both. IMO, > they are not that much different clinically. Personally, I give the [quoted text clipped - 10 lines] > > DrG What I mean by "slicker" can be discerned by rubbing the lens between your fingers with a little bit of saline. It is definitely a "qualitative" test rather than a "quantitative" one. I also like to let the lens sit in the palm of my hand and observe it while it dries out. I find that the lenses are really close in clinical performance, except where the size, shape, and edge design are relevant, and those are individual patient variables. The price point may be the deciding factor in some cases. Of course, the introduction of the Acuvue Senefilcon lens won't be the end to the parade of silicone-hydrogel lenses, as Ocular Sciences will introduce theirs sometime in '06. I suspect that it will incorporate the phosphorylcholine technology. My practice is now at the point where I dispense very few conventional hydrogel lenses. Silicone-hydrogels and Proclears account for 80% of my new contact lens business. DrG > What I mean by "slicker" can be discerned by rubbing the lens between > your fingers with a little bit of saline. It is definitely a > "qualitative" test rather than a "quantitative" one. Yep, I use a similar "slickness test" -- using Aquify MPS. As I mentioned, by day 2, the N&D seemed significantly "slicker" than the Purevision. Again, that may be due to my tear chemistry interacting with the lense & MPS. > I find that the lenses are really close in clinical performance, except > where the size, shape, and edge design are relevant, and those are > individual patient variables. The price point may be the deciding > factor in some cases. You're the doc, so you've seen more of this than I have. I can only speak from my personal, first-hand experience. I'm not sure *why* the Purevision comfort degraded so rapidly over the day for me, but I know it did. I really wanted to like the lense but....oh well. > Of course, the introduction of the Acuvue Senefilcon lens won't be the > end to the parade of silicone-hydrogel lenses, as Ocular Sciences will > introduce theirs sometime in '06. I suspect that it will incorporate > the phosphorylcholine technology. I'm kind of anxious to try Oasys based on your posts, and what I've heard from folks across the pond who have worn them. N&D are okay lenses for me, but as with school, why settle for a 'B' if you can get an 'A' (if so be Oasys works out as an 'A' for me) > My practice is now at the point where I dispense very few conventional > hydrogel lenses. Silicone-hydrogels and Proclears account for 80% of > my new contact lens business. Pretty exciting times, eh? Finally some significant new technology for contact lenses. Do you think we're ever going to get SiHi Dailies (safe to nap in or 1 day overnight if you need to, but otherwise toss 'em)? Keith > Pretty exciting times, eh? Finally some significant new technology for > contact lenses. Do you think we're ever going to get SiHi Dailies (safe > to nap in or 1 day overnight if you need to, but otherwise toss 'em)? > > Keith Quite probably it could in time (amortize the R&D first). However, I don't know why someone would want to toss a lens at the end of the day when they could wear it 24/7. DrG I doubt it. Dailies are sold at a much cheaper per lens price, I assume, for people to afford changing them every day, rather than once per month. Selling si-hy lenses as dailies would mean they would be sold at a much lower per lens price than they are currently. And even if sold as "dailies", if people know they are silicon hydrogels, which normally are sold as 30 day EW, some might buy the "dailies" and wear them for a month ew, greatly reducing the manurfacturer's income. Why would you prefer "dailies"? If one can safely wear lenses EW now, and not have to bother with removal and insertion of lenses each night and morning (not to mention getting up during the night and being able to see, without fumbling to find your eyeglasses), why would one want to use "dailies"? > > Pretty exciting times, eh? Finally some significant new technology for > > contact lenses. Do you think we're ever going to get SiHi Dailies (safe [quoted text clipped - 8 lines] > > DrG It's not that I "prefer" dailies, but in fact, simply because some people can tolerate EW/CW contacts by no means means *everyone* can. There's even still disagreement amongst various eye docs over whether they should push CW or not. There are a number of docs who post on contactlensespectrum who only prescribe CW if the customer insists. Besides that, there continues to be a strong market for "dailies" despite the newer, safer SiHi EW/CW lenses. Some folks actually *like* having a brand new pair of lenses each day, and not dealing with any solutions. Everyone's eyes are different, and some people are better served by a flexible wear schedule rather than CW. Additionally, plenty of people nap in their lenses, but don't care to wear them overnight. Having cheap SiHi dailies might serve that populace as well. I personally like the new tech, but great science or not, just because the FDA approves something (like Vioxx) doesn't mean we won't have to pay the piper later on as we become enlightened about the long-term effects... Keith > Why would you prefer "dailies"? If one can safely wear lenses EW now, and > not have to bother with removal and insertion of lenses each night and [quoted text clipped - 14 lines] > > > > DrG > It's not that I "prefer" dailies, but in fact, simply because some > people can tolerate EW/CW contacts by no means means *everyone* can. [quoted text clipped - 15 lines] > pay the piper later on as we become enlightened about the long-term > effects... I have yet to run across a "cheap" silicone-hydrogel lens. I think that is the crux of the problem. Companies have spent millions of dollars on R&D, FDA studies, and marketing, not to mention litigation, to bring this new technology to the consumer. I don't expect to see a silicone-hydrogel lens selling for $0.75 anytime soon. DrG > Currently I am wearing the Acuvue Senefilcon (Oasys) and have been for > the past month or so. I like it very much. Are these also 30 day silicone hydrogels? How do they compare with the other two? What do you like better about them? Thank you. The Acuvue Senefilcon lenses will not initially have approval for 30 day continous wear, but should have that approval by the end of November. What do I like better about them? I just don't have the sense of contact lenses in my eyes, and the vision is quite good as well.... DrG > Currently I am wearing the Acuvue Senefilcon (Oasys) and have been for > the past month or so. I like it very much. It is really gratifying to > know how far contact lenses have come in the past few years...and how > much better they might still become. > > DrG The Oasys finally appears on the US Acuvue site now. What is the dK of the Oasys? How does its permeability compare with Purevision and N&D? I'm surprised the info on the web site says nothing about oxygen permeability, nothing about silicon hydrogel, or extended wear. The dk/t of the Oasys is in between the Purevision and the Focus N&D...i.e. similar to the O2Optix. I am told that the lens is approved for one week of continuous wear as a two-week lens, and they expect approval for 30 day continuous wear sometime in November. But, I have not independently verified any of this. Just repeating what I have been told by sales and marketing. DrG I just got my lenses in and like you thought they were for extended wear. They are not. They are not only daily wear lenses, but the package insert says you should start at 8 hours and build to full time over a few days. So much for the hype. I'm not impressed, and depending on how my trial patients react (I'm giving trials to about 8 patients, I might just send 'em back! w.stacy, o.d. >The dk/t of the Oasys is in between the Purevision and the Focus >N&D...i.e. similar to the O2Optix. I am told that the lens is approved [quoted text clipped - 7 lines] > > Well, the product is clearly designed and positioned for 30 days continuous wear, and if not now FDA approved as such, no doubt will be. As far as I am concerned, this is a superior product and I am not about to send mine back. I predict that your trial patients will be quite enthusiastic about them. Much improved over the Advance, I agree. DrG OK, I just got off the phone with my sales rep. The Oasys is only approved for daily wear at the moment, but should have FDA approval for continuous wear in November. DrG Seems they could have waited 3 more months, to avoid the unnecessary explaining that will have to be done, but whatever... I hope they work out as well as the hype. w.stacy, o.d. >OK, I just got off the phone with my sales rep. > [quoted text clipped - 4 lines] > > > Now that Purevision is available once more in the USA, one wonders how these > two 30 day-approved silicon hydrogel lenses compare. I think it would be > interesting to hear from eye doctors who have prescribed both, and from > patients who have tried both, to hear how they compare. Morgan PB, Efron N. Comparative clinical performance of two silicone hydrogel contact lenses for continuous wear. Clin Exp Optom. 2002 May;85(3):183-92. Background: Silicone hydrogel soft contact lenses are now available for use on a 30-day continuous wear basis. The aim of this study was to compare the clinical performance of two such lenses. Methods: In a single-centre, randomised, subject-masked, two-period crossover study, 30 subjects wore a pair of PureVision lenses (Bausch & Lomb) and a pair of Focus Night & Day lenses (CIBA Vision), alternately, for successive eight-week periods. Assessment was made of lens fit and surface characteristics, logMAR visual acuity, ocular response and subjective reaction. Results: Lens fit, deposition and post-lens debris were similar for the two lens types. High contrast visual acuity was statistically significantly better for the PureVision lens, as was the subject-reported quality of vision, although these differences were not considered clinically significant. For both lenses, limbal and conjunctival redness reduced throughout the duration of the study, whereas there was a slight increase in the overall amount of corneal staining. The incidence of mucin balls peaked four weeks after commencing lens wear and began to decline thereafter; more mucin balls were noticed in subjects wearing Focus Night & Day lenses. No differences between the lenses were observed for any other biomicroscopic signs. Conclusions: This study demonstrates similar clinical performance with the two silicone hydrogel lenses evaluated. We believe that, with careful monitoring, both of these new-generation lenses can be prescribed for continuous wear. Full text (pdf) at: http://snipurl.com/h4dh |
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