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- Herausgeber: Bentham Science Publishers
- Kategorie: Fachliteratur
- Serie: Ophthalmology: Current and Future Developments
- Sprache: Englisch
Contemporary Scleral Lenses: Theory and Application, provides comprehensive information about scleral lenses. Chapters of this volume have been contributed by renowned scleral lens experts and cover a variety of interesting topics. These topics include the history and evolution of scleral lenses, basic scleral lens structure, optics and customizable features of scleral lenses, analysis of ocular surface shape, ocular surface topography and advances in optometry technology. These topics give readers an explanation of how to utilize diagnostic equipment in optometry practice and enables practitioners to employ a scientific and objective approach to scleral lens fitting.
Key features of this volume include:
- A straightforward approach to ophthalmic examination flow, evaluation and documentation
- A review of Scleral lens care and handling
- Descriptions of a variety of complex medical and ocular indications for scleral lenses
- Strategic tips to promote your own scleral lens practice
- A unique perspective of esteemed corneal specialists regarding the collaborative care of the patient
This textbook is a suitable reference for ophthalmology students and practitioners. This text will assist practitioners in enhancing their scleral lens practice by providing them useful information for improving patient vision, ocular surface rehabilitation and quality of life.
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Seitenzahl: 780
Veröffentlichungsjahr: 2017
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Ophthalmology: Current and Future Developments
(Volume 4)
(Contemporary Scleral Lenses: Theory and Application)
Edited by
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FOREWORD
The re-emergence of the scleral lens – in its modern design – is a recent technological and medical advancement in the care of patients with distorted and diseased corneas. These devices are capable of providing a phenomenal improvement of vision with remarkable comfort. The improvement in quality of life these devices offer cannot be minimized.
When healthcare makes significant advances, the need for education on such developments is vital, so that more healthcare practitioners become trained in employing an innovation and, as a result, more people benefit. It is in this context that Contemporary Scleral Lenses: Theory and Application is a most welcome and valuable addition to the literature. This text is edited and written by two eminent clinicians and scholars in the field of scleral lenses, Drs. Melissa Barnett and Lynette Johns. They are aided by some of the most distinguished practitioners in this modality. These experts have between themselves a great number of years of experience with scleral lens management of complex corneas, which they generously share with the reader.
A review of the content of this text reveals that this volume is remarkably comprehensive. It is carefully authored and referenced and starts with an exceptionally interesting historical chapter. The reader will be taken through lens design and optics but also the topography of the ocular surface. A complete chapter is dedicated to relevant instrumentation used in a scleral lens practice. Several chapters are devoted to the assessment of ocular health, lens fit and complications. All chapters are richly illustrated by carefully selected images. This makes Contemporary Scleral Lenses: Theory and Application a most useful educational tool. Optimal scleral lens fitting is carefully described along with potential complications. Integrated throughout the text are thoughtful and useful problem solving recommendations.
As we become more accustomed to scleral lenses in anterior segment management, we realize that scleral lenses do not need to be limited to the abnormal eye. They indeed may be utilized for the normal eye. An entire chapter addresses this indication.
The comprehensive design of this book describes everything from the beginning to the end and from the simplest to the most complex. Therefore, it makes an appreciated information source for the student or the novice. However, this text book with its wealth of information, the number of clinical pearls and the quality of illustrations offer even the experienced and most seasoned scleral lens practitioners valuable information and opportunities to learn.
Drs. Barnett and Johns are to be congratulated on the completion of their exceptionally useful and impressive text, Contemporary Scleral Lenses: Theory and Application, which is arriving at a time when we have a relative lack of educational material. This text book will most certainly find a place in my personal library and computer.
Jan P. G. Bergmanson Brien A. Holden Professor of Optometry Texas Eye Research and Technology Center University of Houston College of Optometry 4901 Calhoun Rd, Houston, Texas 77204 USAPREFACE
Contemporary Scleral Lenses: Theory and Application covers a vast array of scleral lens topics to inspire novice practitioners and provide valuable pearls to experienced practitioners. From the fascinating history of scleral lenses and how they evolved to the modern scleral lenses used in clinical practice today, this book highlights major advances in scleral lenses. The description of basic lens structure, optics and customizable features combined with the characterization of ocular surface shape intricacies allow the reader to conceptualize and appreciate the unique fitting relationship of a scleral lens. Scleral lens fitting had long been described as an art, however cutting edge information on technology in the scleral lens practice emphasizes the evolving scientific and objective approach to scleral lens fitting.
Examination flow, evaluation and documentation can help even the expert scleral lens practitioner. For those interested in setting up a scleral lens practice, an entire chapter is dedicated to recruiting and marketing the scleral lens practice. For the student and novice practitioner, a chapter is solely dedicated to scleral lens care and handling. There are a variety of complex medical and ocular indications for scleral lenses that are described in detail. These patients require many different specialists for their ocular and systemic care, and the unique perspective from esteemed corneal specialists regarding collaborative care of the scleral lens patient is included in this book. Utilization of scleral lenses for patients with regular corneas is gaining popularity and is also covered.
The purpose of this book is to aid the student, new and proficient practitioners to fit, evaluate, identify and manage scleral lens complications. We hope that this text will help practitioners to grow their scleral lens practice, collaborate with other practitioners and, most importantly, help patients to improve their vision, rehabilitate their ocular surface and improve their quality of life.
The future of scleral lenses requires exploring the intricacies of this modality. There is so much research that needs to be done with scleral lenses. Multiple authors provide their opinions and strategies when facing unique challenges of scleral lenses that are not described in publications elsewhere. We hope that this text will inspire further scleral lens research and publications.
We are honored to have this opportunity to publish this text. We thank you for reading and learning about this modality, which in turn helps patients improve their lives with scleral lenses. We hope that Contemporary Scleral Lenses: Theory and Application is a welcome reference that assists you in implementing scleral lenses into your practice.
ACKNOWLEDGEMENTS
It was an incredibly daunting thought to even imagine writing a book on contemporary scleral lenses. Many thanks and sincere gratitude to Matthew Kennedy and his wife Rebecca Kennedy, OD who encouraged us to undertake this project.
The unremitting encouragement and sacrifice of our families made it possible to devote the endless hours and years to complete this text. We would especially like to thank Todd, Alex and Drew Erickson and Khaled Imad for their unwavering love and support as we embarked on this formidable, yet incredible journey.
It is not possible to write this text without a collaborative effort. We are so appreciative of the support of our global scleral lens community to come together, cheer us on and contribute to this text. This work would not have been possible without the assistance of our authors. Many thanks to our authors: Bruce Baldwin, Jan Bergmanson, Tim Bowden, Patrick Caroline, Karen Carrasquillo, Gregory DeNaeyer, Barry Eiden, Karolien Elving-Kokke, Damon Ezekiel, Don Ezekiel, Deborah Jacobs, Jason Jedlicka, Randy Kojima, Carina Koppen, Jennifer Li, Michael J. Lipson, Jason Marsack, Jennifer McMahon, Brooke Messer, Langis Michaud, Henny Otten, Young Kee Park, Ken Pullum, Perry Rosenthal, Muriel Schornack, Jeffrey Sonsino, Mindy Toabe, Eef van der Worp, Esther-Simone Visser, Reints Visser, Maria K. Walker, Stephanie Woo and Geunyoung Yoon.
List of Contributors
PROLOGUE
Our introduction to scleral lenses would not have been possible without the innovation and insight of the four unique pioneers who were the first to utilize and describe modern scleral lenses using gas permeable materials: Don Ezekiel, Perry Rosenthal, Rients Visser, and Ken Pullum. We are honored that each contributed to this text. Please enjoy the personal recounts of their individual experiences with scleral lenses.
Don Ezekiel
Our pathology lecturer in the optometry course was an ophthalmologist Ken Bardon Brown. Ken studied in London and worked with Joseph Dallos. He told of his experiences with fitting glass scleral lenses and of their benefits for patients. My father who was an optometrist spoke of optometry’s future with the need to specialise and not be another optometrist. So contact lenses became my specialty. Soon after I graduated, I went to Sydney and spent a month with a prominent optometrist and long time editor of the Australian journal, Loyd Hewitt, learning his technique of fitting scleral lenses. In 1963, after being recently married, we travelled to London to further my knowledge in contact lenses. While there I passed the “Fellow of the Association of Contact Lens Practitioners” (FACLP) and the “Diploma of Contact Lens Practice”(DCLP) exams.
After graduation I worked at Perth's major hospital which gave me an introduction to Moorfields Eye hospital and to Frederick Ridley (pioneer of IOLs) who was head of the contact lens clinic. He encouraged me to spend sessions at the outpatients clinic where scleral lenses were fitted to a range of eye conditions that I had only previously read about in text books. Among the specialists I met and became friends with were Montague Ruben (a register at the time) and Norman Bier, the most prominent contact lens practitioner at the time in London and author of the very best book on fitting contact lenses.
I applied for a position at Hamblin’s contact lens centre in New Cavendish street under contact lens pioneer Joseph Dallos. I was told he was difficult to work with, but for me he was a wonderful teacher and father figure. He only fitted glass scleral lenses. Dallos and Bier reported at the same time that fenestrating a lens allowed for all day lens wear without Sattler's veiling. Dallos told me how he worked out how to take a mould of an eye and how he came to fenestrate a lens.
Dallos, Bier and Ruben all advised and talked me into making my own lenses (another story!) As Dallos emphasised that only then could I be sure to supply my patients with lenses with accurate details. (Don’t trust what you are given!). He also emphasised that it will allow you to develop and innovate new designs and lenses. My wife never forgave them!!
On my return to Perth, I started a specialty contact lens practice to make lenses for my patients. A group of ophthalmologists who had worked and trained at Moorfield's in London included Professor Ida Mann who was responsible for getting Dallos to London where he established the first contact lens clinic at Moorfield's. Incidentally, Professor Mann and I actually lived in the same suburb. These London trained ophthalmologists living in Perth were familiar with the benefits of scleral lenses for patients and referred patients specifically for scleral lenses. Among the patients were a constant stream of babies who had cataracts surgery. I would go into theatre, take a mould (invariably a good impression of the lower canthus with minimal cornea impression!) There had to be a easier and better way.
I now had a small laboratory making lenses for my patients. All corneal lens patients were fitted with GP lenses so why were we using PMMA for scleral lenses? We were using Boston materials so I flew to Boston (if you take a globe the world and pass a needle through the centre from Perth you come out just past Boston. I could not be further away).
The owners of Polymer Technology were Perry Rosenthal and Lou Major. I met with them and asked that they supply me with large GP blanks to make scleral lenses. Perry’s response was that “No one fits scleral lenses anymore!” I told him he was wrong. Lou who was responsible for the manufacture of the materials eventually promised to make large GP blanks. Nothing happened! Every week I sent at least two telex messages asking for the blanks. Lou told me later of the growing pile of telex requests on his desk, so he eventually made the blanks for me.
Initially I refitted happy scleral lens patients with GP scleral lenses. All found them to be more comfortable to wear. Was it the oxygen permeability or the surface quality of the material that resulted in a more comfortable lens that could be worn all day? GP materials are heat sensitive so all lenses are lathe turned and not made from moulds taken from patients casts. Although Dallos was first to describe taking an impression of the eye, in the time I worked with him, he never took an impression of an eye. After fitting a patient, he made a duplicate of the lens. These he stored/arranged the lenses on three shelves as small, medium and large. He would look at a patients eye and select what he thought was a close fit and modify the lens from there. The first preformed scleral lens?
From my experiences with scleral lenses I worked out the most common lens parameters and from these we made standard paediatric scleral lenses in two diameters. Babies would be referred and we fit them with these lenses. (All with the power of +30.00D). As the child grew, we would modify the lens power on the same lens as needed. A paper on the lens was published in Contact Lens Spectrum some years ago on the Paediatric GP Scleral lens.
I was fitting scleral patients with all interesting conditions with GP scleral lenses with good results. All lenses were fenestrated. This resulted in the original paper I read at the annual BCLA meeting in Harrogate. Irving Fatt reported on the meeting and on my paper. He reported that the consensus from the meeting was that “no one thought the results were valid or believable as there would not be sufficient oxygen transmission through the lens to make the use of the GP material of any benefit.” I subsequently read a paper and presented a video on my fitting technique at a meeting of the ISCLS in France. This included patients with a range of optical conditions that only a scleral lens would satisfy. Irving Fatt was at the meeting. He commented that I was clearly getting results. If I sent him lenses and lens designs, he would make calculations of the oxygen transmissions through the lens. His calculations reported that the eye received five times more oxygen to the cornea that the cornea required.
I gave all of my collection of old contact lenses and antique optical equipment including a bench to manufacture glass scleral lenses, numerous scleral fitting sets including a glass fitting set from Feinbloom (including some of his moulds), and original Czech lenses in their original glass vials) to Pat Caroline at Pacific University, together with all the correspondence from Irving Fatt and other pioneers that I corresponded with. It seems like I collected and kept everything that is now of historical value. Pat visited me in Perth and we went through the collection and correspondence. I lost count of the times he said “Oh my God.”
Soon after the paper was published, Perry Rosenthal called and visited me in Perth. I showed him patients with a range of conditions who had been fitted with GP scleral lenses. We went to the lab and I showed him how we made lenses. No secrets. No patents. It is a wonderful lens for patients that was not readily available and any person interested in the lens was welcome to all the knowledge and technology. Perry saw the results and the rest is history.
It is very satisfying for me that scleral lenses are now being widely available for patients for whom it is often the only option to achieve vision and comfort. Dallos would be pleased.
Almost all readily available GP scleral lenses now available are sealed. I have only fitted fenestrated scleral lenses. The argument that this lens is more difficult to fit as the lens settles might be true, but now with the lens fitting sets incorporating designs of keratoconic and reverse geometry preformed lenses, it is not difficult to find a fitting lens and to estimate the amount of lens settling at the initial consultation. It is not rocket science.
The continual flushing system of tears from behind the lens and the ease of inserting a non-sealed lens, especially for the paediatric patient, results in a lens that is worn comfortably for the full day without any problems. A lens that allows the exchange of tears and the removal of debris from beneath the lens results in a healthy lens for the cornea. I believe the GP scleral lenses in the near future will be fit for our patients with normal corneas.
The use of gas permeable materials was a logical progression. For me it seems that the stars crossed. I was fortunate to have patients referred to me specifically for scleral lenses and to have a facility to make whatever lens that I wanted.
Getting the materials was the first hurdle. The hardest hurdle to overcome was getting practitioners to understand that fitting the scleral lens was not difficult. It is often a much needed and the only lens option for patients to obtain optimal vision with all day wearing comfort.
Perry Rosenthal
In 1986 I was referred a patient whose only seeing eye had undergone a traumatic rupture that, after its repair, was characterized by a large anterior staphyloma and 8 diopters of astigmatism. Its vision was not correctable to functional levels with spectacles and surgery was contraindicated. Moreover, his distorted cornea was incapable of supporting a rigid corneal contact lens. I then recalled Don Ezekiel’s pioneering work on fitting fenestrated gas-permeable scleral lenses, but the distorted shape of his cornea made it impossible to prevent the air bubbles from intruding on the visual axis. The only remaining option for restoring functional vision was to fit his eye with a non-fenestrated scleral lens. Coincidentally, at Polymer Technology, we had recently developed a new generation of rigid polymers with gas-permeability properties adequate to avoid the need to augment the supply of corneal oxygen with air bubbles during scleral lens wear and I fitted this eye with the first non-fenestrated gas-permeable scleral lens. The result was 20/30 vision, all day wearing and excellent tolerance. I remember thinking that it couldn’t be that easy and it wasn’t: my efforts to fit the next several patients was stymied by the development of lens suction. However, because the success of my first patient proved the potential viability of non-fenestrated GP scleral lenses, I embarked on what turned out to be a multiyear scleral lens design development program that was ultimately based on the use of mathematical spline functions. This turned out to be the breakthrough for fitting these devices.
Rients Visser
From the day I started my contact lens practice back in 1970, I have been fitting contact lenses and scleral lenses for patients with a variety of medical conditions. I have always been driven by the question, “How can I help patients who don’t have any options for treating their ocular and visual problems?”
In the beginning, I would see patients who had been wearing scleral lenses for a long time, in some cases more than 30 years. These patients had been wearing scleral lenses that were made of gas-impermeable materials such as glass or polymethyl methacrylate (PMMA), which was introduced later. Moreover, the indications for fitting patients with scleral lenses have changed over the years. When I started my contact lens practice, I saw patients with corneal scarring due to wounds inflicted during the Second World War or corneal scars resulting from tuberculosis or measles. Unfortunately, though, I also frequently saw opaque, vascularized corneas with corneal edema that resulted from severe hypoxia associated with wearing glass or PMMA scleral lenses for years; some of these patients even needed corneal transplantation. Advanced keratoconus and exposure keratitis were also frequent indications for scleral lenses.
Because PMMA scleral lenses produce an unacceptable level of corneal hypoxia, in the late sixties I designed and fitted PMMA corneal contact lenses, and later hydrogel lenses. However, I still prescribed scleral lenses (albeit with limited wearing time) for managing certain corneal conditions for which other lens types and treatments were not feasible. In these cases, I hand-molded thermoplastic PMMA scleral lenses and fitted these lenses to the patient’s eye.
The report of the first successful use of gas-permeable haptic lenses by Donald Ezekiel [1] in 1983 was—for me—a new starting point in fitting scleral lenses, as these lenses significantly reduced the risk of hypoxic complications. After reading this publication, I immediately commissioned Polymer Technology to produce gas-permeable buttons for scleral lenses; in 1985, they delivered on this request, and Equalens II buttons were available for scleral lenses, marking the beginning of a very exciting chapter in my scleral lens practice. We quickly saw highly promising results by combining this highly gas-permeable material with our preformed scleral lens fitting methods, yielding good lens tolerance and providing safe and effective treatment [2, 3]. Importantly, wearing time also increased considerably. Later work by other scleral lens fitters confirmed that scleral lenses made of highly gas-permeable materials perform better [4, 5].
The 1990s was a landmark decade in the modern era of scleral contact lens design. First, a front-surface cylinder—with a haptic truncation that provided stabilization—was introduced to improve vision [6]. Next, a breakthrough—the back-surface toric scleral lens—was introduced by our team in collaboration with the Dutch contact lens company Procornea in Eerbeek, the Netherlands [7-9]. Importantly, studies of scleral shape supported our own clinical experience with back-surface toric lenses by demonstrating that the shape of the anterior sclera is often asymmetrical (i.e., one or more segments of the sclera are either steeper or flatter than other scleral segments) [10, 11]. Moreover, these studies revealed that the shape of the cornea-scleral junction and the anterior sclera is often tangential rather than curved, driving the development of bitangential-shaped scleral lenses in a joint endeavor with the Dutch contact lens company NKL Contactlenzen in Emmen, the Netherlands [12]. The introduction of back-surface toric scleral lenses now enabled practitioners to achieve a more precise scleral lens fitting and resulted in greater patient satisfaction. Furthermore, the high stability of these toric scleral lenses enabled the use of front-surface cylinders and the ability to provide other optical corrections such as bifocal, prism, and aberration corrections.
The process of fitting scleral lenses requires more than simply using your hands and your head; you also need to use your heart. The ability to regain visual acuity, often after years of suffering with poor vision, helps get patients back to work and back into society; this is what has driven me for four decades and continues to drive me every day.
Helping patients is—of course—at the heart of what we do. But we cannot stop there. Continuing to develop new and improved fitting techniques and teaching colleagues through practical courses and lectures help ensure that scleral lenses and scleral lens practice will continue to improve.
Ken Pullum
Most people make forward, backward or sideways career moves. In all honesty, most of mine were divine interventions by my GA (guardian angel). There have been quite a few, and for as long as I can remember, but the first to impact on my time in optometry was before I entered public exams at school, although I did not appreciate the effect of that one for a few years. This was in the days before everyone went swanning off on the gap year between leaving school and going to university. I thought the organisation VSO (Voluntary Service Overseas) had obvious adventurous attractions. I put in a completely inadequate application which was rejected, even after I appealed and asked them to reconsider. VSO helpfully suggested I would have more to offer as a graduate in a few years time.
My father was a manufacturing optician and set up a small business making spectacles for some of the local ophthalmic opticians, the correct UK term at the time for the professional group later undergoing a makeover and a rename as optometrists. There was no other careers advice at all. No-one could accuse me of being one of the star pupils, and there were quite a few times when I nearly gave up, or when the City University gave upon me. I just salvaged an indifferent degree, notably when I handed in the whole years second year course work two weeks before the end of year exams in the subject I found the most difficult. The tutor was livid pink, but deep down was a kindly man and recognised undergraduates’ frailties. Maybe he also recognised my belated ability to focus on the task in hand had some merit. Who knows, but I just survived that one. Actually there was another student who did exactly the same to the same lecturer, but handed in hers an hour earlier. Anyway, I scraped through the second year, but it was damaging to the final degree outcome.
That would have made a difference if I was joining optometry now … I wouldn’t have been on a long list for a long list, let alone a short list for a position in the UK hospital eye service. But at the time, only a small number wanted to go along that route, and initially, I wasn’t one of them. I had a pre-registration appointment with Andrew Field, one of the practitioners who sent some work to my father’s business, and a top flight pre-reg post it turned out to be, I would say. However, in the middle of the final exams, an invitation to come along for a conducted tour of Moorfields Contact Lens Department appeared on the notice board in the students common room. I didn’t see it, but a friend told me about it. I think my GA must have been behind it. Five of us responded, which by co-incidence, is the same number of days in the week. It turned out that there was a day on offer at the department, as a pre-reg, for each day. I was given Thursdays and started two weeks later. How could I apply for VSO when such a wonderful opportunity had just come my way, even if completely by accident.
My supervisor, Jennifer Chaston, had a different style to my private practice supervisor, but we all learned so much that year. The department was largely manned by dispensing opticians and a small number of ophthalmic opticians, Jennifer was full time, but most of the others were sessional. That year began a transformation in recruitment and from then on the department only took on ophthalmic opticians to the Contact Lens Department staff. There was another group of practitioners who were appointed at the inception of the CLD in 1951. These were not dispensers, or ophthalmic opticians, but state registered nurses, mostly male, who had achieved an ophthalmic diploma. I imagine that back in 1951, there would have been a brief meeting during which the then director pointed to one of them and said …”Trodd! You will make and fit contact lenses.” I don’t think there would have been any training or certainly no dissent, and so Troddy just got on with it. I joined when he was taking on the most difficult cases, working solely with PMMA impression sclerals, doing a wonderful job under very difficult circumstances.
The following year, the organisation of the contact lens department had moved along in leaps and bounds. Monty Ruben, the consultant director, and Jennifer recognised the growing need for research in contact lens practice. The single all week pre-reg appointee that year was Michel Guillon, a different type to the not so famous five in my year. He was able and driven to develop the research requirement, even as a pre-reg. None from the previous year were motivated in the same way, and some had already left or did so soon after. But I was going nowhere, and pleased that too much of an involvement in the research activities was not a pre-requisite. I did not have the same academic leaning, preferring to focus on the many and varied clinical challenges that came in on a regular basis. So if I had gone away on a far flung remote VSO destination four years earlier, I would not have seen the notice pinned up at City University, and my Thursdays at Moorfields in the pre-reg year would not have happened.
On qualifying, I immediately stepped up my days at Moorfields to two a week. Two or three years later, ophthalmic opticians became renamed and reborn as optometrists with the foundation of the British College of Optometrists. Jennifer moved on to pastures new, and Geoff Woodward replaced her as senior optometrist. The department continued to expand apace, he was soon appointed as the first principal Optometrist of the Contact Lens Department, and Michel replaced Geoff as senior. After a few years, Michel also moved on to Sydney to further his skills as a research optometrist, vacating his position as senior optometrist. Three or four people applied for the vacancy, including myself. I think it would be fair to say I had the most experience in the specific clinical skills required by the department, but the hospital administration had had plenty of time to assess my possible organisational skills, and came to a conclusion that “Couldn’t organise a bunfight in a bakery” would fit well. Perhaps a bit unfair, but the person who was appointed did a better job than I would have done running the day to day matters.
Actually, it was my GA coming to my rescue again. I had made friends with Troddy when few others in the optometry group made any impact at all. He allowed me into what had been naughtily referred to as the Inner Sanctum and I was already sharing the impression PMMA scleral workload with him, and more to the point, learning the needful first hand at the sharp end. My second major interview followed soon after being turned down for the full time senior post. Geoff and I were having a corridor discussion. I pointed out that Troddy would be retiring in five years, and the department would need someone to replace him. Geoff said, “OK, start next week.” I promised to be there five years, and that was over thirty five years ago, so I more than honoured my side of the agreement. Now, I would have had to have filled in a 20 page internet application form and there would have been a dozen other contenders. At the time, no-one was interested.
Troddy did retire five years later, and sadly died within a few months. I wish I could have shared with him the gas permeable development, but that was not to be. There was a fully functional contact lens manufacturing section within the department, and one or two heads had come and gone in the time I had been on the staff. One day, Lou, the head at the time, stunned me by declaring that he did not want to make any scleral lenses for me. I was already making all the PMMA fitted shells, but the powering procedures were awkward. I would have thought manufacturing, which involved ending up with oil and grease all over your hands, would be more appropriately separated from the clinical activities. However, the general consensus was that if I wanted to carry on with the project, I’d have to do it all myself. This was an amazing John McEnroe style “Are you being serious?” moment, but in reality was another divine intervention from my GA. I was forced to learn the manufacturing skills, but what an asset that turned out to be in the years to come. When Lou retired, I wrote on his leaving card to say that I now realise he always had my best interests at heart. We had a good laugh, and he took it in the spirit of friendship it was meant.
In the late 1980’s and early 1990’s high DK gas permeable materials replaced PMMA. The change was introduced at a late stage of material science development, so there was no need to find our feet with the early attempts which would have been ineffective with scleral lenses. In short, gas permeable materials simultaneously transformed scleral lens clinical practice and manufacturing. Moorfields was set up for RGP corneal lenses in the Contact Lens Service (recategorised from a Department), but would have needed a complete overhaul to take on RGP scleral lens production. We were looking at a massive task transferring most of our scleral lens wearers from PMMA to RGP, needing refitting in the reformed style, and lenses issued. Moorfields supported my establishment of Innovative Sclerals, and that became the preferred method for scleral lens delivery rather than on site. Where possible in that time, we transferred much of the production to Moorfields for the hospital’s own internal use, ending up with a joint process for both preformed and impression scleral lenses.
We established an excellent working relationship for 20 years, until finally, my partners were all looking to retire, and it would have been impossible for me to carry on alone. This time, it was B&L, rather than my GA coming to the rescue and took over manufacture of the Innovative Sclerals range. And of course, at about the same time, every contact lens manufacturing company on the planet entered into what suddenly became the most exciting new development in contact lenses in recent times.
This is my 43rd year in specialised contact lens practice. If I was to be starting my career from the beginning, I’d do it all again. I have had massive help and support over the years from the establishment at Moorfields, Oxford Eye Hospital, my manufacturing partners, and I was able to learn so much from my colleagues at Moorfields. The British National Health Service allows health care practitioners in the UK to practise without having to offload the costs to the patients, so this has always been a major contribution when trying to develop clinical procedure. We can treat billionaires and people who do not have two pennies to rub together with equitability, so we are able to deliver a service where and when it is need most. And of course, who needs to be born with a silver spoon when you have a guardian angel looking after you at every step.
Melissa Barnett and Lynette Johns
However your journey begins, whether it is from the guidance of an esteemed mentor, a unique patient that requires additional expertise, the opportunity to help people or your guardian angel nudging you, we hope that this text will help you along the way.
REFERENCES
[1]Ezekiel D.. Gas permeable haptic lenses.J Br Contact Lens Assoc1983615816110.1016/S0141-7037(83)80064-0[2]Visser R.. Een nieuwe toekomst voor hoog-zuurstofdoorlatende scleralenzen bij verschillende pathologie.Visus199031116[3]Kok J.H., Visser R.. Treatment of ocular surface disorders and dry eyes with high gas-permeable scleral lenses.Cornea199211651852210.1097/00003226-199211000-000061468214[4]Tan D.T., Pullum K.W., Buckley R.J.. Medical applications of scleral contact lenses: 2. Gas-permeable scleral contact lenses.Cornea199514213013710.1097/00003226-199503000-000017743793[5]Rosenthal P., Croteau A.. Fluid-ventilated, gas-permeable scleral contact lens is an effective option for managing severe ocular surface disease and many corneal disorders that would otherwise require penetrating keratoplasty.Eye Contact Lens200531313013410.1097/01.ICL.0000152492.98553.8D15894881[6]Visser E-S.. Advanced contact lens fitting. Part five: The scleral contact lens: clinical indications.Optician19972141520[7]Visser E-S., Visser R., Van Lier H.J.. Advantages of toric scleral lenses.Optom. Vis. Sci.200683423323610.1097/01.opx.0000214297.38421.1516614579[8]Visser E-S., Visser R., van Lier H.J., Otten H.M.. Modern scleral lenses part I: clinical features.Eye Contact Lens2007331132010.1097/01.icl.0000233217.68379.d517224674[9]Visser E-S., Visser R., van Lier H.J., Otten H.M.. Modern scleral lenses part II: patient satisfaction.Eye Contact Lens2007331212510.1097/01.icl.0000228964.74647.2517224675[10]Van der Worp E., Graf T., Caroline P.. Exploring beyond the corneal borders.Contact Lens Spectr.201062632[11]Tan B., Graham A.D., Tsechpenakis G., Lin M.C.. A novel analytical method using OCT to describe the corneoscleral junction.Optom. Vis. Sci.201491665065710.1097/OPX.000000000000026724830372[12]Visser E-S., Van der Linden B.J., Otten H.M., Van der Lelij A., Visser R.. Medical applications and outcomes of bitangential scleral lenses.Optom. Vis. Sci.201390101078108510.1097/OPX.000000000000001823974663History of Scleral Lenses
Timothy J. Bowden1,†,Melissa Barnett2, *Abstract
Scleral lenses have existed for centuries, longer than any other type of contact lens. They were first conceptualized by Leonardo DaVinci in the early 16th century and were first manufactured in Europe in the late 1800s. The first scleral lenses were blown glass scleral shells without power made in 1887 by Fredrich A. Müller and Albert C. Müller. The primary indication for these scleral lenses was to manage ocular surface disease. In 1889, Adolf Eugen Gaston Fick described the use of scleral lenses with optics added to correct vision. In 1889, Eugene Kalt described contact lenses as orthopedic appliances for the treatment of keratoconus. In that same year, August Müeller created a scleral lens for himself to correct his own 14D of high myopia. Modern advances of scleral lenses have overcome their previous shortcomings, including lens-induced corneal edema due to poor transmissibility of oxygen through the lens and poor reproducibility. Contemporary scleral lenses have re-emerged from a long history of contact lens successes and some failures. In recent years, there has been a burst of new designs and innovations worldwide. With modern materials, manufacturing, and advanced scanning equipment, scleral lenses are now very innovative and a million miles away from their early beginnings.
INTRODUCTION
A question that is often asked is: when and by whom were contact lenses invented? Well, contact lenses were not so much invented as evolved. There have been many stages in this development, some theoretical, but in the main much more practical. Today, contact lenses are largely used for cosmetic reasons, but they originally were designed to deal with medical problems including keratoconus and Symblepharon. Most of the early contact lenses were made by
artificial eye makers. Who can be better to make something to fit onto the front surface of an eye and under the eyelids than a person who would already have the skills required?
Why were the first contact lenses designed as scleral lenses? This was a result of them being made by artificial eye makers. The first contact lenses were supported by the sclera, and the optic portion vaulted over the cornea. They could as easily have been made as corneal lenses. In fact, this happened in Japan when Kyoichi Tanaka designed his first contact lens. He had never seen a contact lens before, so what he designed was actually a corneal lens. This was the start of what was to become Menicon. It has now turned full circle. With new materials and new measuring, fitting, and manufacturing techniques, many eye care practitioners are turning to scleral lenses for improved vision and comfort for their visually compromised patients.
Artificial eye making originated in Egypt around 2000 BC to ensure that Egyptians could see in the afterlife, and it gradually spread throughout Europe, first through Venice and later through Germany, the UK and then the US (Fig. 1). Artificial eye making was big business. Eye damage and eye loss were very common due to frequent, severe eye infections resulting from poor hygiene and no antibiotics, emerging industrial processes using lime and hot metals, and the non-availability of protective eyewear.
Fig. (1)) Images of artificial eyes.“The Optician” of 28th July 1898 reported that 2,000,000 artificial eyes were produced in the German Empire each year, and a single French firm was producing 300,000 per year. “The Optician” of 1st June 1899 reported a horse being fitted with an artificial eye made of vulcanite: “There is nothing a lover of horses dislikes more than a disfigured animal”. It is no co-incidence that the earliest contact lenses from the Müller brothers of Wiesbaden, Germany, looked like artificial eyes, with the opaque scleral portion including representations of scleral and conjunctival blood vessels, but having a clear optic portion.
EARLY THEORISTS
It has previously been widely reported that the illustration in Leonardo da Vinci’s Codex D, folio 3, of 1508 depicting a man with his head in a bowl of water somehow showed the invention of a contact lens (Fig. 2). However, in the re-translation by Robert Heitz [1], this was not a prototype contact lens, but the beginning of understanding corneal neutralization. René Descartes, a French philosopher, mathematician, and scientist, described in his Discourse of La Dioptrique [2] in 1637 that a fluid-filled tube held against the eye enlarged the size of the retinal image. Philip de la Hire, a French mathematician, presented his dissertation in 1685 On the Neutralization of the Cornea [3]. He also speculated about whether the cause of myopia was either axial or refractive. Pierre Demours, a French physician, zoologist, and translator, and his father, a pharmacist, were the first to mention a conical cornea (keratoconus) in 1747 [4]. Pierre Demours also had a disagreement with Jean Descemet about a certain membrane in the cornea. Burchard Mauchart, 1748, John ‘Chevalier’ Taylor, 1766 [5], and Pickford [6], 1844, all made mention of keratoconus, but the first adequate description of keratoconus (Fig. 3) was published by John Nottingham in 1854 [7]. A slit lamp view of keratoconus is shown in Fig. (4).
Fig. (2)) The da Vinci Codex. Fig. (3)) Keratoconus described by Nottingham. Fig. (4)) Modern view of keratoconus.
