Specialist contact lens fitting

What is meant by the term ‘specialist contact lens fitting’? Or put another way, what would be considered non-specialist contact lens fitting? Is there such a thing as routine contact lens fitting? Soft or silicone hydrogel fitting for daily wear would probably be considered as routine contact lens fitting, but would extended or flexible wear remain in the same category or would they be considered a specialist fit? Different eras will classify different products as being ‘specialist’. Certainly twenty years ago soft toric contact lenses were considered as being speciality lenses but today would be thought of as routine lenses. Conversely, gas permeable lenses were thought of as mainstream twenty years ago but now are considered as speciality lenses. Although this would not be the same globally, as in some countries (such as Netherlands, France and Japan) gas permeable lens fitting remains popular and is not on the decline as in other countries (Canada, Australia and Sweden) [1]. Bandage soft lenses applied after surface laser refractive procedures would be considered as therapeutic lenses but in reality they are just plano thin hydrogel lenses worn constantly for 3–4 days to allow the underlying epithelium to convalesce and are then removed [2]. Some patients find that wearing hydrogel lenses during periods when they suffer from seasonal allergies actually improves their ocular comfort as the contact lens acts as a barrier to the allergen [3] and [4]. Scleral lenses have long been considered speciality lenses, apart from a time when they were the only lenses available but at that time all contact lens work would have been considered speciality practice! Nowadays we see the advent of mini-scleral designs and we see large diameter gas permeable lenses too. It is possible that these lenses increase the popularity of gas permeable lenses again and they become more main stream. So it would seem that the lines between routine and speciality contact lens fitting are not clear. Whether a lens is classed a specialist fit or not would depend on the lens type, why it was fitted, where in the world the fitting was being done and even the era in which it was fitted. This begs the question as to what would be considered entry level knowledge in contact lens fitting. This may not be an issue for most BCLA members or CLAE readers but certainly would be for bodies such as the College of Optometrists (UK) or the Association of British Dispensing Opticians when they are planning the final registration examinations for budding practitioners or when planning the level of higher level qualifications such as College Certificates or Diplomas. Similarly for training institutions when they are planning their course content. This becomes even trickier when trying to devise a qualification that spans across many countries, like the European Diploma in Optometry and Optics. How do we know if the training and examination level is correct? One way would be to analyse things when they go wrong and if patterns of malpractice are seen then maybe that could be used as an indicator to more training being needed. There were 162 Fitness to Practice Hearing at the General Optical Council between 2001 and 2010. Forty-seven of these were clinically related case, 39 fraud related, and 76 others. Of the clinical ones only 3 were contact lens related. So it would appear that as whole, in the profession, contact lens clinical skills are not being questioned too often (although it seems a few of us can’t keep our hands out the cookie jar!).

Future of contact lens usage

I was recently part of a small committee looking at higher qualifications in contact lens practice and the discussion turned to future technologies. There was mention of different materials and different applications of contact lenses. Drug delivery with contact lenses was discussed as this has been talked about in the literature for a while. The first paper I could find that talked about using contact lenses for drug delivery dates back over 40 years. There was a review paper in CLAE in 2008 that looked specifically at this too [1]. However, where are these products? Why are we not seeing them in the market place? Maybe the technology is not quite there yet, or maybe patents are prohibiting usage or maybe the market is not big enough to develop such products? We do have lenses on the market with slow release of lubricating agents but not therapeutic agents used for ocular or systemic conditions. Contact lenses with pathogen detectors may be part of our contact lens armoury of the future and again we can already see papers in the literature that have trialled this technology for glucose monitoring in diabetics or lactate concentration in the tear film. Future contact lenses may incorporate better optics based on aberration control and we see this starting to emerge with aspheric designs designed to minimise spherical aberration. Irregular corneas can be fitted with topography based designs and again this technology exists and is being used by some manufacturers in their designs already. Moreover, the topography based fitting of irregular corneas is certainly something we see a lot of today and CLAE has seen many articles related to this over the last decade or so. What about further into the future? Well one interesting area must the 3-dimensional contact lenses, or contact lenses with electronic devices built in that simulate a display screen. A little like the virtual display spectacles that are already sold by electronics companies. It does not take much of a stretch of the imagination to see a large electronic company taking this technology on and making it viable. Will we see people on the train watching movies on these electronic virtual reality contact lenses? I think we will, but when is harder to know.

Towards standardization of UV eye protection:what can be learned from photodermatology?

While knowledge about standardization of skin protection against ultraviolet radiation (UVR) has progressed over the past few decades, there is no uniform and generally accepted standardized measurement for UV eye protection. The literature provides solid evidence that UV can induce considerable damage to structures of the eye. As well as damaging the eyelids and periorbital skin, chronic UV exposure may also affect the conjunctiva and lens. Clinically, this damage can manifest as skin cancer and premature skin ageing as well as the development of pterygia and premature cortical cataracts. Modern eye protection, used daily, offers the opportunity to prevent these adverse sequelae of lifelong UV exposure. A standardized, reliable and comprehensive label for consumers and professionals is currently lacking. In this review we (i) summarize the existing literature about UV radiation-induced damage to the eye and surrounding skin; (ii) review the recent technological advances in UV protection by means of lenses; (iii) review the definition of the Eye-Sun Protection Factor (E-SPF®), which describes the intrinsic UV protection properties of lenses and lens coating materials based on their capacity to absorb or reflect UV radiation; and (iv) propose a strategy for establishing the biological relevance of the E-SPF. © 2013 John Wiley & Sons A/S.

Evaluating the effect of splitting cylindrical power on improving patient tolerance to toric lens misalignment

Purpose: Evaluating the impact of splitting toric power on patient tolerance to misorientation such as with intraocular lens rotation. Setting: University vision clinic. Methods: Healthy, non astigmats had +1.50D astigmatism induced with spectacle lenses at 90°, 135°, 180° and +3.00D at 90°. Two correcting cylindrical lenses of the opposite sign and half the power each were subsequently added to the trial frame misaligned by 0°, 5° or 10° in a random order and misorientated from the initial axis in a clockwise direction by up to 15° in 5° steps. A second group of adapted astigmats with between 1.00 and 3.00DC had their astigmatism corrected with two toric spectacle lenses of half the power separated by 0°, 5° or 10° and misorientated from the initial axis in both directions by up to 15° in 5° steps. Distance, high contrast visual acuity was measured using a computerised test chart at each lens misalignment and misorientation. Results: Misorientation of the split toric lenses caused a statistically significant drop in visual acuity (F= 70.341; p< 0.001). Comparatively better acuities were observed around 180°, as anticipated (F= 3.775; p= 0.035). Misaligning the split toric power produced no benefit in visual acuity retention with axis misorientation when subjects had astigmatism induced with a low (F= 2.190, p= 0.129) or high cylinder (F= 0.491, p= 0.617) or in the adapted astigmats (F= 0.120, p= 0.887). Conclusion: Misalignment of toric lens power split across the front and back lens surfaces had no beneficial effect on distance visual acuity, but also no negative effect. © 2013 British Contact Lens Association.

Ultraviolet damage to the eye revisited:eye-sun protection factor (E-SPF®), a new ultraviolet protection label for eyewear

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of lenses has been lacking. Among the general lay public, misconceptions on eye-sun protection have been identified. For example, sun protection is mainly ascribed to sunglasses, but less so to clear lenses. Skin malignancies in the periorbital region are frequent, but usual topical skin protection does not include the lids. Recent research utilized exact dosimetry and demonstrated relevant differences in UV burden to the eye and skin at a given ambient irradiation. Chronic UV effects on the cornea and lens are cumulative, so effective UV protection of the eyes is important for all age groups and should be used systematically. Protection of children's eyes is especially important, because UV transmittance is higher at a very young age, allowing higher levels of UV radiation to reach the crystalline lens and even the retina. Sunglasses as well as clear lenses (plano and prescription) effectively reduce transmittance of UV radiation. However, an important share of the UV burden to the eye is explained by back reflection of radiation from lenses to the eye. UV radiation incident from an angle of 135°-150° behind a lens wearer is reflected from the back side of lenses. The usual antireflective coatings considerably increase reflection of UV radiation. To provide reliable labeling of the protective potential of lenses, an eye-sun protection factor (E-SPF®) has been developed. It integrates UV transmission as well as UV reflectance of lenses. The E-SPF® compares well with established skin-sun protection factors and provides clear messages to eye health care providers and to lay consumers. © 2014 Behar-Cohen et al, This work is published by Dove Medical Press Ltd.

The eye and vision:an overview

The eye is the major organ of vision and highly specialized for photoreception. It focusses light from an object onto the light-sensitive retina. Changes in specialized neurons in the retina result in nerve action potentials which are relayed to the brain via the optic nerve. Visual processing by the brain results in ‘visual perception’, the construction of a sensory image which is consciously appreciated as vision. All other structures of the eye are subsidiary to this function, either by facilitating focusing of light rays or by supporting the tissues of the eye. This chapter is an introduction to the various parts of the eye including the eyelids and associated structures, conjunctiva, cornea, sclera, iris, lens, vitreous body, retina, optic disc and nerve, and orbit. This chapter describes the functions of these various structures and their importance in achieving a visual image.

Contact lens interactions with the tear film

Biochemical changes brought about by the influence of the contact lens on the tear film are conveniently split into two categories. Firstly, the lens can remove or reduce the levels of specific components in the tear film, and secondly, the lens can augment the tear film, by stimulating the influx of new components or increasing the level of existing components. The most obvious tear film components for study in this context are lipids, proteins, mucins and electrolytes. The interactions are affected by the properties of the lens, the characteristics of the individual wearer and the wear schedule. An additional complicating factor is the fact that the lens is many times thicker than the tear film and any immobilised tear components will be more extensively exposed to oxygen and UV radiation than is the case in the absence of a lens. It is arguably the lipoidal components that are most markedly affected by lens wear, since their immobilisation on the lens surface markedly increases their susceptibility to autoxidative degradation. The limited information that is available highlights the importance of subject specificity and suggests that lipid oxidation phenomena are potentially important in contributing to the 'end of day' discomfort of symptomatic contact lens patients. It is clear that tear lipids, although regarded as relatively inert for many years, are now seen as a reactive and potentially important family of compounds in the search for understanding of contact lens-induced discomfort. The influence of the lens on tear proteins shows the greatest range of complexity. Deposition and denaturation can stimulate immune response, lower molecular weight proteins can be extensively absorbed into the lens matrix and the lens can stimulate cascade or upregulation processes leading either to the generation of additional proteins and peptides or an increase in concentration of existing components. Added to this is the stimulating influence of the lens on vascular leakage leading to the influx of plasma proteins such as albumin. The evidence from studies of mucin expression in tears is not consistent and conclusive. This is in part because sample sources, lens materials and methods of analysis vary considerably, and in some cases the study population numbers are low. Expression levels show mucin and material specificity but clear patterns of behaviour are elusive. The electrolyte composition of tears is significantly different from that of other body fluids. Sodium and potassium dominate but potassium ion concentrations in tears are much higher than in serum levels. Calcium and magnesium concentrations in tears are lower than in serum but closer to interstitial fluids. The contact lens provides the potential for increased osmolarity through enhanced evaporation and differential electrolyte concentrations between the anterior and posterior tear films. Since the changes in ocular biochemistry consequent upon contact lens wear are known to be subject-dependent - as indeed is wearer response to the lens - pre-characterisation of individual participant tear chemistry in clinical studies would enhance understanding of these complex effects. © 2013 Elsevier Ltd.

Adverse events and discontinuations during 18 months of silicone hydrogel contact lens wear

PURPOSE. To report differences in the incidence of adverse events and discontinuations found in a group of neophyte contact wearers using two different silicone hydrogel contact lenses on a daily- and continuous-wear basis during an 18-month period. METHODS. Sixty-one subjects were initially examined, and 53 were eligible to participate in the study. Eligible subjects were randomly assigned to wear one of two silicone hydrogel materials: lotrafilcon A or balafilcon A lenses on a daily- or continuous-wear basis. After an initial screening, subjects were monitored weekly for the first month and then after 3, 6, 12, and 18 months. The incidence of adverse events, including corneal infiltrative events, superior epithelial arcuate lesions, and contact lens-induced papillary conjunctivitis, and discontinuations in each of the four contact lens groups were recorded. RESULTS. Twenty-two adverse events were found. A higher incidence of adverse events was found in subjects wearing lotrafilcon A lenses than in those wearing balafilcon A lenses (χ = 4.40, P=0.04). There were fewer adverse events in subjects wearing lenses on a daily-wear basis than in those wearing lenses on a continuous-wear basis (χ = 5.98, P=0.01). Eight subjects discontinued from the study as a result of recurrent corneal infiltrative events (one), vision problems (two), excessive ocular discomfort (one), relocation (one), noncompliance with the study protocol (one), and being lost to follow-up (two). No significant differences were found in the number of discontinuations between the two lens types (χ = 0.66, P=0.42) and wearing regimens (χ = 0.08, P=0.78). CONCLUSIONS. Lotrafilcon A lenses were associated with a higher incidence of adverse events than balafilcon A lenses were, and this difference is attributed to the difference in the incidence of corneal infiltrative events. Subjects wearing lenses on a daily-wear basis had fewer adverse events than did subjects wearing lenses on a continuous-wear basis. Both lens types and wearing regimens showed a similar incidence of discontinuations. © 2007 Lippincott Williams & Wilkins, Inc.

Editorial

Welcome to the latest issue of Contact Lens and Anterior Eye. In this issue, Kuldeep Razaida provides a fascinating look at fitting prosthetic lenses to patients in India. I had the good fortune of visiting his clinic in August 2006 at the LV Prasad Eye Institute in Hyderabad, India and was humbled by the vast expertise within the one building. The institute started in 1987 and is the brainchild of the infamous Professor Rao. I think there are few such places in the world where the clinicians work so passionately in treating such interesting patients (for details regarding the LV Prasad Eye Institute see www.lvpei.org). I was in Hyderabad courtesy of IACLE (see issue 29:5 for an editorial by Judith Morris and Sonja Cronje about IACLE) and was able to share ideas with contact lens educators from across the world (for more information on IACLE see www.iacle.org). The issue contains some regular contact lens type papers too; with our aging population readers will be particularly interested in a paper by Mike Freeman and Neil Charman looking at modified monovision with diffractive bifocal lenses. There is an article looking at visual problems with video display terminal use and a study looking at the effects of surface treatment of silicone hydrogel contact lenses. There is an interesting piece from Dr Aisling Mann of Aston University looking at tear protein analysis; this article contains one CET point too for readers who complete the attached multiple choice questions before the relevant deadline. Also, congratulations to the BCLA members who successfully undertook the Fellowship of the BCLA at this year's BCLA conference in Manchester. If you are interested in undertaking the Fellowship please look at the details on the BCLA web page (http://www.bcla.org.uk/fellowship.asp). Amongst the case reports in this issue of CLAE you will notice one from Andrew Elder-Smith, this particular case report was presented as part of his successful Fellowship submission in 2006 and was thought to be of particular good quality by the examiners who asked Andrew to kindly submit it for publication to Contact Lens and Anterior Eye as an example for potential candidates. Finally, it is my sad duty to report the death of Howard Gee earlier this year, a past council member of the BCLA. Our thoughts and prayers are with his family and friends.

Objective accommodative amplitude and dynamics with the 1CU accommodative intraocular lens

PURPOSE. To compare the objective accommodative amplitude and dynamics of eyes implanted with the one-compartment-unit (1CU; HumanOptics AG, Erlangen, Germany) accommodative intraocular lenses (IOLs) with that measured subjectively. METHODS. Twenty eyes with a 1CU accommodative IOL implanted were refracted and distance and near acuity measured with a logMAR (logarithm of the minimum angle of resolution) chart. The objective accommodative stimulus-response curve for static targets between 0.17 and 4.00 D accommodative demand was measured with the SRW-5000 (Shin-Nippon Commerce Inc., Tokyo, Japan) and PowerRefractor (PlusOptiX, Nürnberg, Germany) autorefractors. Continuous objective recording of dynamic accommodation was measured with the SRW-5000, with the subject viewing a target moving from 0 to 2.50 D at 0.3 Hz through a Badal lens system. Wavefront aberrometry measures (Zywave; Bausch & Lomb, Rochester, NY) were made through undilated pupils. Subjective amplitude of accommodation was measured with the RAF (Royal Air Force accommodation and vergence measurement) rule. RESULTS. Four months after implantation best-corrected acuity was -0.01 ± 0.16 logMAR at distance and 0.60 ± 0.09 logMAR at near. Objectively, the static amplitude of accommodation was 0.72 ± 0.38 D. The average dynamic amplitude of accommodation was 0.71 ± 0.47 D, with a lag behind the target of 0.50 ± 0.48 seconds. Aberrometry showed a decrease in power of the lens-eye combination from the center to the periphery in all subjects (on average, -0.38 ± 0.28 D/mm). Subjective amplitude of accommodation was 2.24 ± 0.42 D. Two years after 1CU implantation, refractive error and distance visual acuity remained relatively stable, but near visual acuity, and the subjective and objective amplitudes of accommodation decreased. CONCLUSIONS. The objective accommodating effects of the 1CU lens appear to be limited, although patients are able to track a moving target. Subjective and objective accommodation was reduced at the 2-year follow-up. The greater subjective amplitude of accommodation is likely to result from the eye's depth of focus of and the aspheric nature of the IOL. Copyright © Association for Research in Vision and Ophthalmology.

Management of dry eye in UK pharmacies

Purpose - To investigate the ability of pharmacy staff in the United Kingdom (UK) to diagnose and treat dry eye. Methods - A mystery shopper technique to simulate a patient with presumed dry eye was used in 50 pharmacy practices in major towns and cities across the UK. Pharmacies were unaware of their involvement in the study. With the exception of a predetermined opening statement to initiate the consultation, no further information was volunteered. Questions asked, diagnoses given, management strategy advised and staff type was recorded immediately after the consultation. Results - The mean number of questions was 4.5 (SD 1.7; range 1–10). The most common question was the duration of symptoms (56%) and the least common was whether the patient had a history of headaches (2%). All pharmacy staff gave a diagnosis, but the majority were incorrect (58%), with only 42% correctly identifying dry eye. Treatment was advised by 92% of pharmacy staff, with the remaining 8% advising referral directly to the patient's GP or optometrist. Dry eye treatments involved topical ocular lubrication via eye drops (90%) and lipid based sprays (10%). However, only 10% gave administration advice, 10% gave dosage advice, 9% asked about contact lens wear, and none offered follow up although 15% also advised GP or optometrist referral. Conclusions - There is a need for improved ophthalmological training amongst pharmacists and pharmacy staff and establishment of cross referral relationships between pharmacies and optometry practices.

The effect of contact lens wear on dynamic ocular surface temperature

Aim: To determine the dynamic emitted temperature changes of the anterior eye during and immediately after wearing different materials and modalities of soft contact lenses. Method: A dynamic, non-contact infrared camera (Thermo-Tracer TH7102MX, NEC San-ei) was used to record the ocular surface temperature (OST) in 48 subjects (mean age 21.7 ± 1.9 years) wearing: lotrafilcon-A contact lenses on a daily wear (LDW; n = 8) or continuous wear (LCW; n = 8) basis; balafilcon-A contact lenses on a daily wear (BDW; n = 8) or continuous wear (BCW; n = 8) basis; etafilcon-A contact lenses on a daily disposable regimen (EDW; n = 8); and no lenses (controls; n = 8). OST was measured continuously five times, for 8 s after a blink, following a minimum of 2 h wear and immediately following lens removal. Absolute temperature, changes in temperature post-blink and the dynamics of temperature changes were calculated. Results: OST immediately following contact lens wear was significantly greater compared to non-lens wearers (37.1 ± 1.7 °C versus 35.0 ± 1.1 °C; p < 0.005), predominantly in the LCW group (38.6 ± 1.0 °C; p < 0.0001). Lens surface temperature was highly correlated (r = 0.97) to, but lower than OST (by -0.62 ± 0.3 °C). There was no difference with modality of wear (DW 37.5 ± 1.6 °C versus CW 37.8 ± 1.9 °C; p = 0.63), but significant differences were found between etafilcon A and silicone hydrogel lens materials (35.3 ± 1.1 °C versus 37.5 ± 1.5 °C; p < 0.0005). Ocular surface cooling following a blink was not significantly affected by contact lens wear with (p = 0.07) or without (p = 0.47) lenses in situ. Conclusions: Ocular surface temperature is greater with hydrogel and greater still with silicone hydrogel contact lenses in situ, regardless of modality of wear. The effect is likely to be due to the thermal transmission properties of a contact lens. © 2004 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Customer loyalty among daily disposable contact lens wearers

Background: Optometric practices offer contact lenses as cash sale items or as part of monthly payment plans. With the contact lens market becoming increasingly competitive, patients are opting to purchase lenses from supermarkets and Internet suppliers. Monthly payment plans are often implemented to improve loyalty. This study aimed to compare behavioural loyalty between monthly payment plan members and non-members. Methods: BBR Optometry Ltd offers a monthly payment plan (Eyelife™) to their contact lens wearers. A retrospective audit of 38 Eyelife™ members (mean. ±. SD: 42.7. ±. 15.0 years) and 30 non-members (mean. ±. SD: 40.8. ±. 16.7 years) was conducted. Revenue and profits generated, service uptake and product sales between the two groups were compared over a fixed period of 18 months. Results: Eyelife™ members generated significantly higher professional fee revenue ( P<. 0.001), £153.96 compared to £83.50, and profits ( P<. 0.001). Eyelife™ members had a higher uptake of eye examinations ( P<. 0.001). The 2 groups demonstrated no significant difference in spectacle sales by volume ( P= 0.790) or value ( P= 0.369). There were also no significant differences in contact lens revenue ( P= 0.337), although Eyelife™ members did receive a discount. The Eyelife™ group incurred higher contact lens costs ( P= 0.037), due to a greater volume of contact lens purchases, 986 units compared to 582. Conclusions: Monthly payment plans improve loyalty among contact lens wearers, particularly service uptake and volume of lens purchases. Additionally the greater professional fees generated, render monthly payment plans an attractive business model and practice builder.

BCLA Pioneers Lecture - evidence basis for patient selection:how to predict contact lens success

Editorial

The detection of kinin activity in contact lens wear

Many factors can be, and have been, attributed to the appearance of complications in lens wear, but the greatest is associated with deposition. Reduced acuity, irritation and inflammatory responses are often referred to as adverse reactions arising as a result of deposition. In this study, particular attention was paid to the potential role of adsorbed proteins in activating, mediating and/or stimulating a host immune response, i.e., the hypothesis that the adsorption of certain proteins from the tears and ocular surfaces may actively affect successful lens wear. In particular, the purpose of this study was to investigate the presence of a group of proteins previously undiscovered in the ocular environment. The intention was to target a family of proteins/glycoproteins that have become prominent recently in a variety of inflammatory responses and disorders at many other mucosal associated sites around the body, e.g. in nasal rhinitis and in joint inflammation. The protein cascade in question is the kinin family of inflammatory mediators. The aim was to investigate their presence in the ocular environment, specifically in relation to contact lens wear, and consequently assess the implications of their discovery. High molecular weight kininogen (HMWK), with its central role in kinin responses, was investigated initially as the marker of kinin activity, with subsequent members examined thereafter.