UK-trained dispensing optician and Specsavers Australia’s Director of Products, Mr Steve O’Leary, delivered a keynote address to open proceedings.He reported that 25 million pairs of spectacles had been dispensed since the company commenced operation in Australia in 2008 and that during that time more than 1,000 optical dispensers had been trained and deployed.On the day, some 130 new dispensing graduates were being celebrated and it was expected that close to 500 delegates would have attended the conference series.Individualised spectacle lensesRepresenting Carl Zeiss Vision was Mr Greg Lee, an independent optical dispenser with experience in many aspects of the spectacle lens-supply chain, including time in the R&D department of SOLA in Adelaide. He traced the development of progressive power spectacle lenses (PPLs) from the original rotated, but fundamentally symmetrical, PPLs through to the asymmetric designs and finally those which were ‘designed by Rx’.{{quote-A:R-W:450-I:2-Q: O’leary reported that 25 million pairs of spectacles had been dispensed since the company commenced operation in Australia. }}The original PPLs, available up to the 1980s, had no real difference between right and left lenses yet were met with some success. The asymmetric designs that followed were an improvent and offered better blur control in the zones outside the ‘corridor’, while the current offerings have a lens form that is optimised for each Rx. Additionally, early examples had spherical distance zones, whereas newer iterations have introduced asphericity to improve overall performance.The advent of atoric surfacing, in which the back surface carried the spherical and cylindrical components, marked the beginning of complex lens surfacing that ultimately led to the freeform surfaces that now dominate the market. Freeform surfacing is synonymous with direct surface shaping under numerical control (CNC digital surfacing), which signalled the end of more conventional surfacing technologies.With freeform lenses, every lens is calculated individually and that allows other factors, including individual fitting factors such as frame wrap, vertex distance, pantoscopic tilt, eye rotation characteristics, pupil size, etc to be incorporated in calculations. The advance has lead to a prescription that is regarded as an ‘as worn’ Rx.Generally, freeform PPLs have the Rx on the back surface and the front surface is usually spherical – although double-sided, freeform PPLs do exist. The design software minimises power errors by taking as many factors as possible into account, however, the complexity of such surfaces are a challenge to polish – hence the use of soft polishing. Best results are achieved with a minimum of soft polishing, as the final surface is then closer to the intended topography. Customised freeform lenses also provide an enhanced field-of-view.However, the arrival of atoric surfaces, and the more complex PPLs that followed, necessitated the introduction of ‘as measured’ data with each lens so that, at the time of dispensing, the lens powers can be assessed for accuracy with conventional measuring instruments such as focimeters. The applicable ISO standards now refer to Position of Wear (POW) and padded bridges are useful for adjusting the seating height of the frame on the PPL wearer.Should troubleshooting become necessary after the appropriateness and accuracy of the appliance has been confirmed, factors such as Rx differences between previous and new appliances, patient expectations, adaptation time allowed, reading distance, head position and posture, and changes to the form of the lenses need to be investigated. A repeat refraction was suggested should all of the obvious factors be confirmed as appropriate, yet probls persist.
KEYNOTE SPEAKERS |
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 Greg Lee |
 James Gibbins |
 Kathryn Rose |
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Measuring for successMr Timothy Haigh from the RMIT (Melbourne) Certificate IV Optical Dispensing course gave a detailed overview of what needs to be measured accurately when dispensing spectacles. The presentation had a clear focus on the measurent of PD, seg heights, etc when selecting and dispensing PPLs.After more than 48 years in ophthalmic optics, this author learned that the use of a PD rule and corneal reflection of a point light source, eg, a pen torch, to measure a patient’s PD is called the Viktorin method. Although Hofstetter’s Dictionary of Visual Science and Related Clinical Terms (5th edition) does not mention it, Wilson and Daras do mention it in their Practical Optical Dispensing text widely used by Australian dispensing courses.Haigh detailed the use of PD rules, pupilometers, and digital measuring devices such as the tablet-computer-based Smart Mirror devices. If a patient has a strabismus, an occluder might be necessary when measuring their PDs, while he also noted that errors could be introduced when using a PD rule if there are significant differences between patient and dispenser PDs.In that circumstance, Jalie’s rule of sixteenths needs to be invoked, ie, the PD needs to be corrected by 1/16th for each mm of PD difference. Crucially, this must be corrected in the ‘opposite’ direction, so if a dispenser’s PD is larger, the patient’s PD needs to be decreased. A far greater error is likely from parallax and it, probably more than any other source of error, has fuelled a shift to pupilometers and later devices – especially as the complexity of spectacle lenses has increased.As errors can be compounded or partially compensatory, monocular measurent errors of 1 mm or more repeated for each eye can result in >2 mm uncertainty. This miscalculation, in PPLs for example, can mean the difference between success and wearer difficulties.{{quote-A:L-W:450-Q: Digital devices are quicker and more conducive to the selection of high-end lenses and appliances, and are certainly more than ‘retail theatre’ }}Haigh noted that even pupilometers make assumptions about the position of the various ocular axes in relation to the corneal reflexes when calculating the data to be displayed. They also ‘estimate’ the near PD based on the measured distance PD. Special height gauges (the Hilco device was mentioned) can be used for vertical lens positioning.Meanwhile, digital measuring devices use POW/‘as worn’ information and measure distance and near PDs at the actual distances. Haigh estimated their binocular uncertainty as 0.2 mm, but noted that the stand-like measuring devices favoured by some are a source of queuing and congestion in a very busy practice.Finally, Haigh then explored some of the sources of probls with each of the methods, including eccentric seating of pupilometers when a patient’s bridge is irregular or broken. He also noted that many dispensers overestimate their measuring skills and the accuracy thereof, especially when PD rules are the preferred tool. Haigh claimed that digital devices are quicker and more conducive to the selection of high-end lenses and appliances, and are certainly more than ‘retail theatre’ as he put it.Myopia controlProfessor Kathryn Rose, Head of Discipline, Orthoptics at UTS, Sydney gave a comprehensive presentation on myopia and an update on where our knowledge is at currently.She summarised myopia as a mismatch between optical and anatomical eye factors, namely axial length (AL), refractive power, and refractive indices of the ocular media, which results in incident light being brought to a focus or foci in front of the retina. Despite those possibilities, she stated that about 99% of myopia is AL-related and although males have longer ALs, they are no more prone to myopia than fales. This is because the refractive state is a biological balance between refractive power and AL, so AL per se is not the ‘answer’.Unlike many anatomical features, the ocular Rxs of the population are not distributed normally, instead it is a kurtotic curve whose peak is around +1 to +1.25 D and whose tails are long. With prevalences around the world ranging from 9.6% (South Africa) to 96.5% (South Korea), it is easy to justify the use of the term ‘epidic’, especially when figures up to 1970 are much lower than those found currently.Tellingly, the prevalence of myopia in adults over 40 years of age does not differ greatly between China, Korea, and Australia but in many countries now, up to 80% of school leavers are myopic. Those findings confirm that myopia is not purely genetic, although it is accepted that some races are more myopia-prone than others.Data from around the world confirm that myopia is not just an East Asian disease and the post-1970 increases must have an environmental component. Interestingly, not all East Asians are afflicted – for example, Nepal has a lower, but increasing, rate of myopia than Australia.{{image8-a:r-w:400}}The greatest changes in a young person’s refractive state occurs between the ages of seven and 12 years and generally, the greater the myopia and the earlier its onset, the higher the final myopia is likely to be. Quoting published data, Rose estimates that by 2050 there will be about five billion myopes in the world and more disturbingly, up to one billion of those will be high myopes with all the probls that level of the disease brings, such as glaucoma, cataract, retinal detachment, and myopic macular degeneration.Myopia risk factors include the level of education attained, the cumulative amount of near work undertaken, and time spent outdoors. Rose and her co-workers first published the latter in 2008. Based on Singapore data using Indian and Chinese groups, it has been shown that despite not being related genetically, each group has been afflicted with similar increases in myopia due to the effects of increased amounts of education.The Sydney Myopia Study (2003 – 2005, Rose was involved) showed that myopia was higher in acadically selective schools and 50% of their students were myopic. Regardless, the association between education and myopia is inconsistent. Intuition would suggest that accommodation (near work) might play a role, but studies in which the need for accommodation was reduced optically, showed no beneficial effect.A meta-analysis of available data shows that the more time spent on near work, the higher the odds of developing myopia, to the extent that the odds of developing myopia increase by about 2% for each additional dioptre-hour (a complex measure of time spent at near that is not as simple as its name suggests). Some are also quick to assign blame to the current over-exposure of the young to digital devices, but those distractions arrived well after the myopia epidic got into full swing and can be excluded as a major aetiological factor.Prevention of myopia rains a challenge and requires significant lifestyle changes that have other impacts beyond myopia related issues. Those with high near exposure and little time outdoors are 2.6x more likely to be myopic at 12 years of age and that likelihood increases to around 16x by 17 years of age.However, it’s been shown that time outdoors is protective against myopia. A major US study (the ORINDA Study), collected data from children with two, one, or no parents who were myopic, and it was shown that although myopic parentage did increase the probability of developing myopia, time outdoors was still shown to be protective.One theory with some traction among researchers is that bright light stimulates the release of retinal dopamine, which is known to inhibit eye growth. In experimental situations, a luminance of 40,000 lux has been shown to block form-deprivation myopia (FDM), but a figure of 10,000 probably has a similar effect. Given that midday on a bright summer’s day can deliver 160,000 to 300,000 lux outdoors, a figure of 10,000 or more can be achieved even when sunglasses and hats are worn.The amount of time outdoors is still the subject of research, but recommendations from some of the leading researchers in the area – including Rose and her colleague, Dr Amanda French – range from 13.75–19.6 hours per week. Current indoor levels are more likely to be around 400 lux and Rose pointed out that impractical amounts of energy and heat would be needed to create even a 10,000 lux therapeutic environment indoors.Obviously, the cheapest, and probably the healthiest, way of achieving anti-myopia levels of light exposure is to get outdoors. However, this is not always easy in countries with especially cold weather, where myopia progression has been shown to be greater in winter.Other treatments have been trialled, including bifocals, PPLs, deliberate under-correction, orthokeratology (OK), special CL designs, and atropine. Bifocals and PPLs resulted in no significant effect and under-correction appeared to make the situation worse in that myopia progressed more than controls. A confounding factor is that because of their age, young myopes must expect some progression of their ametropia simply due to their ongoing growth and that progression can probably continue into their early 20s.While in some studies accommodative lag has been targeted as a possible aetiological factor in myopia, Rose believes the onset of such lag follows the onset of myopia and therefore may be an effect of myopia rather than a cause. The COMET study of PPLs versus single-vision lenses showed PPL usage was slightly beneficial in cases in which accommodative lag and esophoria were present. That group constitutes about 1% of the general population. Most benefit occurred in the first year of wear.OK is also effective but Rose believes that its benefit may only be after the onset of myopia, so it can only be ployed as a progression control measure rather than a prevention strategy. There is also some evidence that the efficacy of OK tapers off over time, with the first three years being the most effective. OK research continues in various centres around the world including Australia. Indeed, research at the ROK group at UNSW headed by Professor Helen Swarbrick showed a significant reduction in AL with OK using a true cross-over study design.Novel CLs that have deliberate peripheral myopic defocus to discourage axial elongation have also been shown to have some beneficial effects. Up to a 34% reduction in myopic progression in the first 12 months have been reported. A significant drop-out rate confounded results, but no rebound effect was reported.Atropine, one of the oldest drugs known, has been studied extensively as an anti-myopia measure. In normal concentrations, the practical side effects on pupil size (dilated) and accommodative amplitude (reduced) are downsides to the treatment. The long-term ramifications of routine dosing rain unknown but adverse reactions are known to occur. Again, the first year of use proves to be the most effective, but the biggest disadvantage uncovered to date relates to a rebound effect.Paradoxically, the absence of a significant rebound effect was found with just 0.01% atropine when that concentration was used as a ‘control’ for a study of higher concentrations. While the efficacy of such a low concentration was an issue, it has been shown to be the optimum regimen. Unfortunately, that concentration is not available commercially, yet.{{image10-a:c-w:600}}In summary, she believes that low dose atropine, an evolved novel CL, and time outdoors are possible answers to the myopia epidic. Any delay or decrease in myopia has the knock-on effect of reducing the number of high myopes (generally ≥5 D). Given their probls, any help is better than none.The myopia probl in China has now reached the stage that degenerative myopic changes are being seen in children less than 17 years of age. Ethnic Chinese children raised in a Sydney environment who averaged about 13.75 hr of outdoor exposure per week have myopia prevalence of about 3%, while their Singapore-based ethnic ‘relatives’ who spend just 3.5 hr outdoors, have a 29% prevalence of myopia. Beyond getting outdoors, treatments to reduce the incidence and severity of myopia are now firming, but it is likely to be some time before a definitive treatment can be ‘prescribed’ with confidence.Frame fitting{{image3-a:l-w:400}}One of the directors of the Australasian College of Optical Dispensing (ACOD), Mr James Gibbins, began his presentation by providing a brief refresher and review of achieving a good final spectacle frame fit by offering a list of ‘dos and don’ts’.Then, after delivering a quick review of the developments of PPLs, he revealed that most failures to adapt to PPLs were dispensing issues and not Rx issues – although he did note that sometimes, wearer resistance can be a contributing factor to difficulties arising. He gave mono PDs, lens heights, and frame adjustments as the most likely probl areas.Based on his decades of teaching optical dispensing, Gibbins also observed that sometimes the best students acadically did not always become the top performing dispensers. He suggested this was because more than just acadic rigour was involved when dealing with the real world and the spectacle wearers that inhabit it.{{quote-A:R-W:450-Q: Sometimes the best students acadically did not always become the top performing dispensers. }}He also warned against occupying patient eye-examination waiting times with frame selection, because their selection might be determined to be unsuitable subsequently and separating some wearers from their newfound frame can prove difficult. Often, those difficulties are based on inadequate frame depth.Frame suitability also depends on forehead positioning, overly full cheeks, and long eyelashes. Consideration of what the final appliance will look like is needed and that will often depend on where the thickest part of the lens is located. Gibbins advised dispensers to adjust the frame to the patient before taking any measurents – especially height measurents. Final checking of completed appliances was recommended for all children’s Rxs at least, if not all patients, paying special attention to atypical Rxs, high Rxs, and PPLs.He warned that a lot was going on inside the head of neophyte PPL candidates and the dispenser needed to instruct, explain, and allay any reservations they may have, and also suggested that key trigger words such as distortion, blur, lack of focus, etc not be used when dispensing, preferring instead to use more nebulous terms such as soft focus and soft peripheral vision instead.The confusion surrounding ‘glare’ was also discussed, especially in the context of lens coatings, as the latter will not reduce true glare, only unwanted surface reflections. What might actually be required is a tint instead.Dispensing and the very young patient{{image7-a:r-w:400}}British dispensing optician and Director of Professional Examinations for the Association of British Dispensing Opticians (ABDO) group, Ms Alicia Thompson, chose children’s spectacle frames as the topic for her presentation. She was able to donstrate, and put into context, the large number of differences and issues that arise when fitting spectacle frames to the very young. As those who are charged with that responsibility regularly will know, it is not an easy task – small adult frames are not appropriate, and the range of frames in Australia is not wide and only available from a few suppliers.To assist her presentation and to make particular points, she brought to Australia life-sized busts of children of various ages and ethnicities and one of a child with Down syndrome.Thompson and her audience agreed that when parents accompany children, the greatest professional difficulties usually involve the parents and not the child. As children are likely to rove any optical appliance that is ill fitting or uncomfortable, she reinforced the message that a suitable frame adjusted appropriately was essential for successful wear. She further advised dispensers to operate at the level of the wearer, even if that meant getting down on hands and knees.Using terms seldom heard of in routine ophthalmic practice such as (nose) apical radius, frame crest height, and bridge projection, Thompson ably donstrated why many frames are unsuited to children because their facial anatomical features are not in an adult configuration. She also warned against fitting frames too tightly along the tples because that leaves indentations, is uncomfortable, and tends to push the appliance forward and down the nose.Thompson recommended against curl sides in any child under two years of age. Using her Afro-Caribbean and Down syndrome busts, she donstrated why extra care was required in those instances. Down syndrome cases are numerous as 70% need an Rx, of which 80% are bifocals, and most require unusually short length-to-bend frame tples.Because opaque rules are seen as threatening (vision-blocking) by some children, she recommended the use of transparent rules and further suggested that the dispenser play peek-a-boo or some other game using the rule before actually using the rule for its intended purpose.Bifocals in Down cases should be fitted relatively high, ie, seg located just under the pupil centre. Glass lenses should never be used in children, while some form of UV protection should also be considered as it has been donstrated that 80% of our UV exposure happens before 18 years of age.
