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PUTTING VIAGRA BACK INTO RGP LENS PRACTICE TONY PHILLIPS.

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Presentation on theme: "PUTTING VIAGRA BACK INTO RGP LENS PRACTICE TONY PHILLIPS."— Presentation transcript:

1 PUTTING VIAGRA BACK INTO RGP LENS PRACTICE TONY PHILLIPS

2 THE DEMISE OF RGPs???? In the 1990s, Nathan Efron forecast the demise of RGP lenses by the year 2,000 In the 1990s, Nathan Efron forecast the demise of RGP lenses by the year 2,000 Then 2001, 2002, 2003, 2004 etc, and, at the latest count, 2010 Then 2001, 2002, 2003, 2004 etc, and, at the latest count, 2010 Horror of horrors, could he actually be correct?! Horror of horrors, could he actually be correct?!

3 PHILIP MORGAN - WORLD SURVEY Of PRESCRIBING HABITS The number of RGPs prescribed in the USA is 7%, 8% in the UK and 5% in Hong Kong. The number of RGPs prescribed in the USA is 7%, 8% in the UK and 5% in Hong Kong. In Australia, the figure is also 5% with 27% of these being prescribed for Ortho-k and around three quarters of the rest being for refits or where RGPs are essential e.g. keratoconus, post-grafts, trauma, etc In Australia, the figure is also 5% with 27% of these being prescribed for Ortho-k and around three quarters of the rest being for refits or where RGPs are essential e.g. keratoconus, post-grafts, trauma, etc

4 So have we effectively already stopped prescribing RGPs? Again, has Nathan’s prediction already come true? So have we effectively already stopped prescribing RGPs? Again, has Nathan’s prediction already come true? Yet in New Zealand the prescribing rate of RGPs is 23% and in Holland is 39% Yet in New Zealand the prescribing rate of RGPs is 23% and in Holland is 39% So what is it that they know that we don’t? So what is it that they know that we don’t? Are we right - or are they??? Are we right - or are they???

5 WHAT I WANT TO COVER To remind ourselves why we should be prescribing RGPs - and not lose the art! To remind ourselves why we should be prescribing RGPs - and not lose the art! Understand why the current situation has arisen Understand why the current situation has arisen Finally give you twenty-one ways in which to improve your RGP practice! Finally give you twenty-one ways in which to improve your RGP practice!

6 THE REASONS FOR PRESCRIBING RGPs Refitting of existing RGP wearers Refitting of existing RGP wearers Some conditions can ONLY be fitted with RGPs e.g. karatoconics, post-grafts, corneal trauma, etc. Some conditions can ONLY be fitted with RGPs e.g. karatoconics, post-grafts, corneal trauma, etc. RGP lenses may be easier to handle e.g. narrow VIPs, enophthalmics, babies, etc. RGP lenses may be easier to handle e.g. narrow VIPs, enophthalmics, babies, etc. Easier to maintain and last longer than many soft lenses. Easier to maintain and last longer than many soft lenses.

7 THE REASONS FOR PRESCRIBING RGPs Some patients will get better acuity with RGPs e.g. irregular astigmats, uncorrected small cyls in soft lens wearers, etc. Some patients will get better acuity with RGPs e.g. irregular astigmats, uncorrected small cyls in soft lens wearers, etc. But is this no longer applicable since aspheric SCLs are now available???? But is this no longer applicable since aspheric SCLs are now available???? Nathan Efron - “Modern approaches using aspheric optical designs result in vision with soft lenses that is just as sharp as that which can be achieved with soft lenses” Nathan Efron - “Modern approaches using aspheric optical designs result in vision with soft lenses that is just as sharp as that which can be achieved with soft lenses” Is this true? Is this true?

8 RGPs and V.A. The results of one 2008 study stated: The results of one 2008 study stated: “…the fitting of aspheric design soft contact lenses does NOT result in superior visual acuity, aberration control or subjective appreciation compared with equivalent spherical soft lenses” and – “…the fitting of aspheric design soft contact lenses does NOT result in superior visual acuity, aberration control or subjective appreciation compared with equivalent spherical soft lenses” and – “….all indicate that the aspheric abberation- controlled design actually reduces vision” And who said this????

9 The man himself! The man himself!

10 RGPs and VA In conclusion on VA and the aspheric lens debate, Trusit Dave stated in the BCLA journal, 2008: In conclusion on VA and the aspheric lens debate, Trusit Dave stated in the BCLA journal, 2008: “If the patient has a high refractive error, spherical aberration will play an important role in visual blur. However, in higher prescriptions also be aware that other factors such as lens movement and rotation will also play a significant role in vision quality. Currently, lenses that are designed to correct spherical aberration have not been shown to be more effective than conventional spherical lenses” By implication, RGP’s will provide better visual quality than most soft lenses

11 VA and RGPs Refractive Surgeon, Dr B Allan, writing in the UK journal ‘Optometry Today’ (2008) stated: Refractive Surgeon, Dr B Allan, writing in the UK journal ‘Optometry Today’ (2008) stated: “The best qualitative approximation of what patients can expect from their vision post-LASIK is what they can see in soft contact lenses. Most post-LASIK patients do not have zero refractive error and it is important to emphasise that some sharpness may be lost. This is particularly important for RGP wearers”

12 REASONS FOR PRESCRIBING RGPs RGP lenses perform better physiologically because there is: RGP lenses perform better physiologically because there is: Less corneal coverage Less corneal coverage Better retro-lens tear flow Better retro-lens tear flow Often greater oxygen permeability Often greater oxygen permeability Often better and sometimes the only alternative in cases such as GPC, recurrent SEALs, marginal dry eye, etc. Often better and sometimes the only alternative in cases such as GPC, recurrent SEALs, marginal dry eye, etc.

13 RGPs & ADVERSE REACTIONS Annual incidence of microbial keratitis in different lens types

14 RGPs & ADVERSE REACTIONS Insight, September, 2008: Insight, September, 2008: “Online/mail order purchase of contact lenses carries five times the risk (of microbial keratitis): 2 Studies” Nathan Efron - textbook: “The incidence of virtually all forms of adverse physiological events is lower in RGP lenses versus soft lenses”. Nathan Efron - textbook: “The incidence of virtually all forms of adverse physiological events is lower in RGP lenses versus soft lenses”.

15 THE REASONS FOR PRESCRIBING RGPs RGP wearers appreciate the skill involved and become loyal, happy patients RGP wearers appreciate the skill involved and become loyal, happy patients Alan Saks writing in Insight, September, 2008 wrote: “Most days I see at least one long-term RGP wearer with at least thirty to forty years of very successful hard/RGP wear. They are generally some of the most trouble-free, loyal and happy patients one can ever hope to see. They make going to work a pleasure”

16 THE REASONS FOR PRESCRIBING RGPs RGP wearers rarely, if ever, reorder through the internet RGP wearers rarely, if ever, reorder through the internet RGP bifocal and multifocal lenses generally give better results in terms of clarity. RGP bifocal and multifocal lenses generally give better results in terms of clarity.

17 REASONS FOR PRESCRIBING RGPs RGPs can be repolished or modified in power within small limits RGPs can be repolished or modified in power within small limits A good knowldge of RGPs is essential if you contemplate doing ortho-k work A good knowldge of RGPs is essential if you contemplate doing ortho-k work As ancillary to this, if ortho-k is shown to slow down or stop the progression of myopia it will hugely take off. As ancillary to this, if ortho-k is shown to slow down or stop the progression of myopia it will hugely take off. Holden - approximately 30% of the world’s population are myopic (1.92 billion) Holden - approximately 30% of the world’s population are myopic (1.92 billion)

18 REASONS FOR PRESCRIBING RGPs RGPs are less affected by dryness and blinking: RGPs are less affected by dryness and blinking: Edwards (2008)”The current investigation showed that the tear film evaporation with soft contact lenses in situ is significantly higher than that from the bare optical surface” Edwards (2008)”The current investigation showed that the tear film evaporation with soft contact lenses in situ is significantly higher than that from the bare optical surface” Tomlinson (1994) “The reduction in visual performance induced by the blink during soft toric lens wear appears to last longer than that produced in RGP lens wear” Tomlinson (1994) “The reduction in visual performance induced by the blink during soft toric lens wear appears to last longer than that produced in RGP lens wear”

19 SO WHY HAS THE PROBLEM ARISEN? Inadequate University teaching Inadequate University teaching Difficulty in Universities getting appropriate patients Difficulty in Universities getting appropriate patients Laboratories like volume and the simpler lens type the better Laboratories like volume and the simpler lens type the better Optometrists’ fear of charging reasonable fees for their time Optometrists’ fear of charging reasonable fees for their time The longer adaptation period for RGPs The longer adaptation period for RGPs

20 SO WHY HAS THE PROBLEM ARISEN? Patient pressure Patient pressure Perceived as quicker and easier for practitioners and, particularly,: Perceived as quicker and easier for practitioners and, particularly,: if their own RGP knowledge is rather mediocre and/or they don’t have appropriate fitting sets and equipment. if their own RGP knowledge is rather mediocre and/or they don’t have appropriate fitting sets and equipment.

21 FEES In Jim Kokkinakis’s excellent article in Mivision (March, 2009) he pointed out that the sales economy is hour glass shaped: In Jim Kokkinakis’s excellent article in Mivision (March, 2009) he pointed out that the sales economy is hour glass shaped: The top 60% of the market seek quality over cost The top 60% of the market seek quality over cost The lower 37% are cost driven and The lower 37% are cost driven and 3% are internet purchasers 3% are internet purchasers Very few are in the middle! Very few are in the middle!

22 FEES The bottom part of the hour glass is divided between the large corporations since all they can advertise is how cheap they are. The quality of The bottom part of the hour glass is divided between the large corporations since all they can advertise is how cheap they are. The quality of the eye examination is the eye examination is not vital to most patients. not vital to most patients. Volume is paramount Volume is paramount The larger, top end of The larger, top end of the hour glass expect a the hour glass expect a high standard of care high standard of care and represent a golden and represent a golden opportunity for specialist, opportunity for specialist, professional image professional image practice including RGP fitting. practice including RGP fitting.

23 SO WHAT CAN BE DONE TO IMPROVE THINGS? More help/enthusiasm from the Universities with undergrad and post-grad courses. More RGP clinical work More help/enthusiasm from the Universities with undergrad and post-grad courses. More RGP clinical work More help from the CCLSA e.g. travelling post-grad courses on RGPs More help from the CCLSA e.g. travelling post-grad courses on RGPs Development of better wetting materials etc. by labs Development of better wetting materials etc. by labs Awareness by practitioners that it is their own interest to learn more on the subject e.g. CCLSA Fellowship, and to acquire the necessary equipment and fitting sets Awareness by practitioners that it is their own interest to learn more on the subject e.g. CCLSA Fellowship, and to acquire the necessary equipment and fitting sets

24 IMPROVING YOUR RGP PRACTICE WHAT YOU CAN DO NOW!!

25 1. Improve your knowledge! How many of you have read a recent text- book or current paper(s) on RGP fitting? How many of you have read a recent text- book or current paper(s) on RGP fitting? There are several good text-books on the market (well, at least one!) There are several good text-books on the market (well, at least one!)

26

27 2. Understand how to write a prescription properly! Please supply: R. C3/7.80:8.30/8.50:8.80/9.90: D Green XO ct 0.15 FOZD 7.40 et 0.16 – 018 VWB Engrave ‘R’ and ‘XO’

28 3. Understand how to manipulate the ‘numbers’ to achieve what you want With very little practice you can understand how to change the curves and diameters to achieve what you want. Those attending the workshop will be experts by the time they leave!

29 4. Reject the obvious potential failures in the first place! High cyls but spherical corneas High cyls but spherical corneas Those with corneal cyls but little or no refractive cyl Those with corneal cyls but little or no refractive cyl Those who work in very dusty atmospheres Those who work in very dusty atmospheres Those who spend a great deal of their time doing contact sports Those who spend a great deal of their time doing contact sports Those who want intermittent wear only Those who want intermittent wear only

30 5. Use the Correct Terminology The correct or incorrect use of wording can have a major effect on the patient’s perception. Andrew Hogan in Optometry Pharma, 2008: “… practitioners who see patients with central serous chorioretinopathy should consider recommending that they cease taking sildenafil (Viagra) which will, of course, be a hard decision”

31 Use the Correct Terminology Imagine if you said to a patient: “Your first choice is a soft lens. Compared to the alternative, these are: Rather slippery, somewhat slimy Rather slippery, somewhat slimy Will give you a slightly poorer standard of vision Will give you a slightly poorer standard of vision Will be more expensive to wear Will be more expensive to wear Will significantly increase your chance of a serious infection Will significantly increase your chance of a serious infection Are more difficult to handle than the alternatives Are more difficult to handle than the alternatives Will tend to dry out more easily,” etc Will tend to dry out more easily,” etc How many would go for them?!!!

32 Use the Correct Terminology Avoid the word ‘Hard’ Avoid the word ‘Hard’ Even avoid the use of the word ‘Rigid’ Even avoid the use of the word ‘Rigid’ Just talk about ‘Gas Permeable’ or ‘GP’ lenses Just talk about ‘Gas Permeable’ or ‘GP’ lenses If necessary, just say that GP lenses are like soft lenses but just a more rigid material and with specific advantages If necessary, just say that GP lenses are like soft lenses but just a more rigid material and with specific advantages

33 6. If in doubt? Start with an RGP lens first. It’s much harder going from a soft to an RGP than vice versa! Start with an RGP lens first. It’s much harder going from a soft to an RGP than vice versa! Also, most RGP wearers, if they are going to fail will usually fail in the first month whereas SCL wearers may take many months to show up as failures (e.g. from mediocre VA, marginal dry eye, unstable toric, etc) Also, most RGP wearers, if they are going to fail will usually fail in the first month whereas SCL wearers may take many months to show up as failures (e.g. from mediocre VA, marginal dry eye, unstable toric, etc) Better to start with an RGP and fail quickly than have problems cropping up along the way over the next two years with soft lenses before they give up Better to start with an RGP and fail quickly than have problems cropping up along the way over the next two years with soft lenses before they give up

34 7. Use an anaesthetic at the fitting appointment The urban myth is that this gives a false impression and can lead to corneal damage Purslow et al, BCLA Jnl 2008 concluded that ; “The use of Proxymetacaine prior to lens fitting had no significant effect on redness or corneal staining compared to a placebo drop and subjects prefer its use for the procedure” “The use of Proxymetacaine prior to lens fitting had no significant effect on redness or corneal staining compared to a placebo drop and subjects prefer its use for the procedure”

35 Use an anaesthetic at the fitting appointment Ed Bennett and Cristina Schnider, CL Spectrum 1993: “A study performed at the Pacific University College of Optometry showed that… no significant physiological problems resulted from the use of one drop of Proparacaine prior to lens application at the fitting visit. In addition, subjects who received the anaesthetic seemed to adapt more rapidly to their lenses and to display a more positive outlook throughout the first month of lens wear.”

36 8. Generally, go larger in Total Diameter Initial comfort is often better with a larger TD lens

37 Choice of diameter Lindsay and Bruce recommend choosing the TD according to the lid position As most eyelids cover the upper part of the cornea and are level or slightly below the lower limbus, most corneas allow a larger TD to be selected.

38 Choice of Total Diameter As stated before: Go for the largest TD possible Go for the largest TD possible Aim for lid attachment if possible Aim for lid attachment if possible Consider the effect of the eyelids Consider the effect of the eyelids

39 9. Fitting Sets From the foregoing it will be essential to have: at least three TD sets e.g. 9.50, and 10.50mm diameters at least three TD sets e.g. 9.50, and 10.50mm diameters Toric sets e.g. 0.4 mm toricity Toric sets e.g. 0.4 mm toricity With time, sets of different BVPs and e values With time, sets of different BVPs and e values And, most importantly: Know ALL the lens parameters and check them for accuracy Know ALL the lens parameters and check them for accuracy

40 10. Ensure the lens edge shape is optimal The ideal edge should be rounded with a tapered front surface (Donna La Hood, 1988). The ideal edge should be rounded with a tapered front surface (Donna La Hood, 1988). A rounded front surface is more important than a rounded back surface or square edge A rounded front surface is more important than a rounded back surface or square edge

41 Ensure the lens edge shape is optimal A very simple quick way to check an edge is with a piece of plasticene pressed into a cube and your slit-lamp on the highest magnification. A very simple quick way to check an edge is with a piece of plasticene pressed into a cube and your slit-lamp on the highest magnification.

42 Ensure the lens edge shape is optimal

43 11. Specify and check the centre and edge thicknesses Look up ct in tables and check!

44 12. Don’t err on the tight side Go for alignment or slightly steep (but not a ‘tight’ edge!) Go for alignment or slightly steep (but not a ‘tight’ edge!)

45 Don’t err on the tight side Remember, a steep lens is not necessarily a tight lens!

46 13. Get the correct Axial Edge Clearance Garry Andrasko in C L Spectrum (1989): Tricurves with narrow peripheral curves are more comfortable than bicurves or tricurves with wide peripheral curves Tricurves with narrow peripheral curves are more comfortable than bicurves or tricurves with wide peripheral curves Lenses with high axial edge lift (> 0.15mm) are less comfortable than lenses with a low edge lift (0.08mm) Lenses with high axial edge lift (> 0.15mm) are less comfortable than lenses with a low edge lift (0.08mm) Blended lenses are more comfortable than non- blended lenses Blended lenses are more comfortable than non- blended lenses

47 14. Lenticulate As a general rule, lenticulate all lenses over + and – 5.00D A lens of TD 9.80mm and BVP +7.00D would be 0.41mm in ct if non-lenticulated but 0.26mm ct if ordered with an FOZD of 7.00, i.e. 60% thinner. This is significantly more comfortable and provides significantly better oxygen transmission

48 15. Mimic any former lens design It is often tempting to go to a ‘modern’ fitting or your favourite design when refitting an existing RGP or PMMA wearer. By all means try to head in that direction but generally speaking try to mimic what they already have. Bear in mind the effect of improved oxygen transmission on corneal shape however!

49 16. Don’t get them back for the first after-care too quick! Warn patients that there IS an adaptive period Warn patients that there IS an adaptive period Warn them that this can be very variable between individuals Warn them that this can be very variable between individuals That initial adaptation will take two or three weeks and sometimes a little longer to completely forget that they’re in their eyes That initial adaptation will take two or three weeks and sometimes a little longer to completely forget that they’re in their eyes Whilst telling them to report any obvious symptoms, don’t get them back for after-care in under two weeks. All they’ll do is whinge! Whilst telling them to report any obvious symptoms, don’t get them back for after-care in under two weeks. All they’ll do is whinge!

50 17. Stress hygiene and cleaning Good hygeine is, of course, essential with any form of contact lens. The pitfalls of soft lens wear (dryness, GPC, etc.) can be avoided by good cleaning and, particularly, the use of Progent, say monthly

51 18. Consider surface treated lenses The use of surface treated materials is equivocal but may help in certain cases. Remember that they cannot be repolished or changed in power in most cases.

52 19. Do over K’s where necessary to check for lens flexure This can affect VA’s and may indicate the need for a toric design, especially in against-the-rule corneas This can affect VA’s and may indicate the need for a toric design, especially in against-the-rule corneas In with-the-rule corneas go slightly flatter if the lens flexes In with-the-rule corneas go slightly flatter if the lens flexes In both cases the lens ct may need to be increased slightly In both cases the lens ct may need to be increased slightly

53 20. Fees! Charge an appropriate fee for all your time, skill, equipment, ancillary staff. You’re worth it! And remember, soft lenses wearers are for now, RGP wearers are for ever!

54 20. Fees Remember that poor fitting fees is one of the main reasons for the low recommendation of contact lenses in this country You need to cover the fitting session, the instruction session and at least three after-cares i.e. around $

55 21. Don’t pre-judge! Keith Edwards (BCLA Jnl. 2002) tested a new B & L RGP design on 51 subjects: 96% wore the lenses successfully 96% wore the lenses successfully Two drop-outs were former soft lens wearers Two drop-outs were former soft lens wearers Two dropped out for visual problems (lenticular astigmatism - but the research protocol did not prevent their exclusion) Two dropped out for visual problems (lenticular astigmatism - but the research protocol did not prevent their exclusion)

56 21. Don’t pre-judge! Johnson and Schnider (1991) Int. C L Clin. carried out a cross-over study where one group of new patients were fitted with RGP lenses and the other half with soft lenses. At the end of six weeks they were swapped over. Johnson and Schnider (1991) Int. C L Clin. carried out a cross-over study where one group of new patients were fitted with RGP lenses and the other half with soft lenses. At the end of six weeks they were swapped over. In a forced choice, 60% preferred the soft lenses and 40% the RGPs. However, 35% also wore the RGPs quite successfully in terms of vision and comfort and could have worn either. In other words, 75% of the group could have successfully worn the RGP lenses and 40% actually preferred them

57 21. Don’t pre-judge! They further noted: That all subjects preferred the RGPs for VA That all subjects preferred the RGPs for VA That all subjects preferred the RGPs for handling and cleaning simplicity That all subjects preferred the RGPs for handling and cleaning simplicity That the preference figure for RGPs of 40% would undoubtedly have risen if the trial had extended beyond six weeks That the preference figure for RGPs of 40% would undoubtedly have risen if the trial had extended beyond six weeks

58 IN SUMMARY Improve your knowledge Improve your knowledge Understand how to write prescriptions properly - and do it! Understand how to write prescriptions properly - and do it! Understand how to manipulate the numbers Understand how to manipulate the numbers Reject the obvious in the first place Reject the obvious in the first place Use the correct terminology with the patient Use the correct terminology with the patient If in doubt, start with an RGP If in doubt, start with an RGP Use an anaesthetic at the fitting appointment Use an anaesthetic at the fitting appointment Use a largish TD where possible Use a largish TD where possible Make sure you have adequate and known fitting sets Make sure you have adequate and known fitting sets Ensure the edge shape is optimal Ensure the edge shape is optimal

59 IN SUMMARY Specify and check the ct and et Specify and check the ct and et Don’t err on the tight side Don’t err on the tight side Ensure the correct aec Ensure the correct aec Lenticulate where appropriate Lenticulate where appropriate Mimic any former lens design Mimic any former lens design Don’t get them back too quick Don’t get them back too quick Stress hygiene and cleaning Stress hygiene and cleaning Consider surface treated materials Consider surface treated materials Do over-k’s where necessary Do over-k’s where necessary Charge appropriate fees Charge appropriate fees Don’t pre-judge Don’t pre-judge

60 CONCLUSION So is it really worth going to all this trouble? van der Worp (2002) stated: van der Worp (2002) stated: “Even small improvements in RGP fits influenced comfort of wear significantly. It should be noted that this could be noted that this could potentially lead to drop out among patients with acceptable among patients with acceptable but not optimal fits” but not optimal fits”

61 CONCLUSION Brad Giedo in CL Spectrum, 2008 Brad Giedo in CL Spectrum, 2008 “If you are truly an advocate of GP lenses and you believe the positive things that you tell your patients about them, then you need to be willing to present GPs as a first option. In my experience this is not how most of you practice so I challenge you to make a conscious effort to include GPs when you consider your initial lens selection. Resist the urge to simply default to soft lenses. You will find that there are many more opportunities to fit GP lenses than you thought possible and you and your patients will be better for it.”


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