When introducing the third Specialist Club meeting for contact lens practitioners, held recently at the ABDO buildings in Aston, founder Nick Atkins (figure 1) mentioned his appreciation to the sadly departed Ron Loveridge. Ron, many readers may remember, established a similarly named ‘club’ in his later years, and it is to be applauded that Atkins has taken up the baton. That said, with a rapid advance in contact lens technologies and modes of practice, the modern Club is necessarily quite a different beast, and the theme of the latest meeting, ‘Successful niche contact lens practice,’ embraced topics from the advanced clinical, through more general patient management, to business practice.
Commercially Niche
Indie Grewel, currently president-elect for the BCLA, was an ideal speaker to introduce the context of what was to follow (figure 2); topics such as topography, high cylinder correction by hybrid lenses, orthokeratology, myopia management and soft lens correction of keratoconus. As the remainder of the day was to focus on more clinical aspects, Grewel immediately pointed out that these topics were all areas of contact lens practice that, not only constituted a specialised service demanded by patients, but would also help differentiate any practice offering them. And increase commercial potential.
Figure 2: Indie Grewel explained how specialism can be profitable.
‘Over time, specs-only patients stay dormant,’ he explained, ‘while contact lenses have positive impact over time.’ Citing a paper by Mark Ritson from 2006,1 he reminded the audience that contact lens patients have been calculated to be 60% more profitable than spectacle wear patients. He then outlined the milestones in the development of his own practice. Starting out just before the 2008 recession hit, Grewel showed that his readiness to embrace new approaches, whether this be the EASE study2 recommendation for fitting lenses to choose spec frames, the use of topographers or the setting up of a myopia management service, had help his practice grow throughout a time many businesses struggled.
Key tips along the way included:
• Technology is excellent, and helps to explain matters clearly to patients.
• Communication is essential for myopia management – this includes pre-myopia discussions, including assessment of the likelihood of myopia developing, and these discussions should be documented. Ask all myopic patients about their kids.
• It is helpful to send out information, including references, to patients rather than rely on them Googling and receiving poor or inaccurate information.
• Keeping abreast of new products is essential – Grewel was keen to mention the recently launched Menicon Bloom and SEED 1-day pure lenses, along with MiSight and the NaturalVue lens, recently given CE mark status for dual purpose correction.
• When discussing price with patients and parents, Grewel suggested pointing out that investment at aged six is helping to slow down myopia and so will result in cost savings in the years to come.
• Keeping up to date with the evidence base is important. Grewel recommended everyone interested in this area download the reports from the International Myopia Institute.3
Correcting the Cylinder
Next up, Phil Thomson (of SynergEyes) led a workshop looking at the various options for correcting astigmatic patients, particularly those who are also presbyopic (figure 3). It has been pointed out that around 45% of presbyopes have astigmatism of 0.75DC or more, and 15% of 1.25DC or more.4
Figure 3\; Phil Thomson (of SynergEyes) led a workshop looking at the various options for correcting astigmatic patient.
Delegates were then asked to discuss how best to correct the following patient; a -2.25DS myope with a 1.25 DC cylinder. Obviously a range of options spring to mind, and factors such as the cyl axis and patient ocular surface health and wearing information may influence choices. Soft torics and RGPs seemed to rule the day. Until, a non-standard axis, a low sphere/high cyl or presbyopia were added to the mix. At this point, no single answer predominated. Furthermore, there now seemed to be an appetite for a mini-scleral option, or now they have cracked the challenges of manufacture and lens robustness, a hybrid lens such as the Duette.
Soft multifocals had the following disadvantages for the presbyopic astigmat:
• Ghosting increases with uncorrected cylinder, and this makes success of simultaneous vision less easy
• Tolerances for higher cylinder correction often means patients find vision quality is not consistent between lenses
• Vision can vary on a day to day basis due to environmental conditions
RGP multifocals have these disadvantages:
• Patient comfort adaptation is ever a challenge
• Care systems might need to be more comprehensive and suffer from compliance issues
• Centration may affect vision, especially for high or oblique
cylinders
• Night vision can be reduced by decentration
• Custom lenses cost money
The Duette lens is a centre-distance (CD) design that allows add powers up to +5.00DS in 0.25DS steps. The CD optic zone size varies from 1.8mm to 4.0mm in 0.1mm steps. Fitting the hybrid lens ‘is easy’:
• The lens base curve is calculated from the corneal curvature:
• 0.1mm flatter than flattest K, but no more than 0.15mm steeper than flattest K
• Fit steeper for higher cyls
• Soft skirt is calculated based on corneal diameter;
• 11.7 or smaller, go for flat skirt (8.4)
• 11.8 or larger, go for medium skirt (8.1)
The dual aspheric design of the lens uses the tear film to neutralise cylinder, and so the lens does not suffer from rotational loss of acuity. Also, the soft cushion enhances tear exchange. The RGP centre floats over cornea and, on blinking, the soft cushion acts like a tear pump. And with UV protection built in, enhanced low light vision, and durability guaranteeing up to six months life with daily wear, Thomson argued this was a case of ‘having your cake and eating it’. ‘This lens corrects Rx beyond most high street options,’ he continued, ‘and the result will be a patient impressed by your practice.’
And with a guaranteed fit after two exchanges or your money back, there seems no reason why the hybrid option should not be available in any contact lens fitting practice.
Soft Lenses for Keratoconus
Seasoned contact lens specialist, Lynn White of Ultravision, next explained why soft lenses should not be ruled out when fitting keratoconics (figure 4). It is fair to say that the default position has always been RGP for ectatic corneas, but White offered a strong argument as to why this needed rethinking. Using audience voting, White first established that the practitioners present all had experience of fitting irregular corneas, the majority with soft or RGP lenses, and a few with hybrid, scleral or semi-scleral lenses.
Figure 4: Lynn White (Ultravision) gauges audience responses.
When asked why they preferred rigid lenses for fitting irregular corneas, the majority suggested ‘quality of vision’ as the main reason. This might be better for us, she went on, but not for the patient. Citing a study from Dundee University from 2007, White noted that up to 71% of keratoconics felt their CLs to be uncomfortable, often only being able to tolerate one at a time.
Soft lenses, on the other hand, offered:
• Improved comfort
• Low levels of staining
• Reduced risk of fall out
• Better all round subjective scores
• Acuities of 6/7.5 or better if specialist soft lenses used
She then asked, ‘Can you go thinner on a soft lens and still see well?’ One study had found that 24 subjects with thicker soft lenses (minimum thickness of 0.4mm) had been refitted with 0.2mm thickness lenses. All but three eyes had found the acuity to be the same or better. Only one preferred the thicker lens, and this was for reasons to do with handling.
Liverpool University have modelled an eye that mirrors changes in shape with IOP fluctuation. When a thin lens is inserted, there is virtually no tear film. A very thick lens behaves like a semi-scleral or rigid fit. On blinking, it sweeps tears away and gives poor vision. By halving thickness, there is better tear lens stability. Pooling of tears under a thick lens gives poor vision, not corrected astigmatism. Poor VA with a specialist lens is likely due to poor fit, not related to its ‘softness’.
Figure 5: Martin Conway (Contamac, left) enthuses about a scleral option.
Some other key points raised in the session included:
• Topography allows calculation of the base curve from the tangential map.
• You can average the central values, and also the steepest and flattest from the 5mm ring, and then add on a correction factor. Ultravision have a downloadable app to help do this.
• The main decision when assessing the cornea, it to gauge if the cone is central or low.
• A lens only needs one minute to settle before assessment. The lens will eventually become immobile if left long enough and look like a tight fit.
• An optimal fit will show;
• 2mm movement on blink
• Engrave that sits at 6
• Centred and comfortable
• Lens will drop on upgaze due to prismatic profile
• A push up test will offer little information of use. General observation should be sufficient.
• Flat fit may show unstable rotation – this may settle after 10 minutes or so and so you may miss the flatness. Look for fluting on eye, though this may disappear after time. Fit observation should take around 30 seconds.
• Tight fit has stable rotation, but may be stuck off-axis. May be discomfort in one location. May not drop in upwards gaze. Lens usually centred.
Instrumentation and myopia
The remaining sessions covered areas of practice such as topographer use, orthokeratology for myopia management and the fitting of scleral lenses and included a selection of both practical sessions and interactive discussion workshops. Look out for more on these in the next few weeks.
• Information on future events can be found at www.specialistclub.uk
References
- Ritson M. Which Patients are More Profitable? Contact Lens Spectrum, March 2006
- Atkins, N et al. Enhancing the approach to selecting eyewear (EASE): a multi-centre, practice-based study into the effect of applying contact lenses prior to spectacle dispensing. Contact Lens & Anterior Eye : the Journal of the British Contact Lens Association. 2009;32(3):103-7
- International Myopia Institute (IMI) Myopia Control Reports Overview and Introduction. Downloadable at www.myopiainstitute.org
- Woods C et al. Clinical performance of an innovative back surface multifocal contact lens in correcting presbyopia. CLAOJ, 1999; 25 176-181