Abstracts
Friday, June 28th
Current Principles of Ortho-K (Patrick Caroline)
The modern renaissance of orthokeratology has been dramatically influenced by the emergence of four technologies, 1. the introduction of reverse geometry lens designs, 2. application of modern corneal mapping techniques, 3. advances in GP materials for overnight lens wear and 4. a greater understanding of the ocular tissues involved in the process. Throughout this lecture we will describe how each of these technologies contributes to the success of the modality. Special emphasis will be directed towards the anatomy of modern reverse geometry lens designs and the influence of the various parameters on topography and optics of the cornea
Patient Selection and Communication Skills (Michael Lipson)
This lecture will detail the evaluation of patient characteristics used to determine candidacy for Orthokeratology. Following that, the course will describe the most important points patients must understand to become successful in the process of Orthokeratology. This includes setting realistic expectations, importance of compliance in keeping follow-up visits as well as lens care and hygiene through the use of a written fitting agreement or informed consent. Overall, this presentation will discuss the steps you must take to satisfy patients and yourself in an Orthokeratology practice.
Analyzing Ocular Surface Shape (Eef van der Worp)
Choosing the right lens design and geometry is of crucial importance in RGP & orthokeratology lens fitting. Suboptimal lens fits can lead to unwanted physiological side effects, possibly playing a role in corneal staining and corneal infiltrates, while negatively influencing ocular comfort and visual outcome of the orthokeratology procedure. Utilizing corneal topography gives a significant benefit in optimizing lens fit and more recently, new technology has shown that it can even help visualize the limbal and anterior ocular shape. This course will describe how the newest instruments on the market – and in the pipeline - can help us better analyse and design different types of contact lenses to better serve the anterior ocular surface
Refraction, Topography and Fluorescein Evaluation (Randy Kojima)
This course will describe the pre and post treatment procedures integral to orthokeratology practice. Refraction, topography and fluorescein evaluation will be reviewed in great detail.
Ortho-K: when it’s a bad idea (John Mountford)
Some patients should never be fitted with Ortho-K, as they end up costing the practitioner a lot of time and money for what is eventually a failed patient. This lecture will cover the common indicators that point to a poor outcome prior to fitting the lenses such as ocular surface issues, corneal topography, astigmatism and initial refractive error amongst others.
Clinical Pearls for the Beginner (Basil Bloom)
A round up of important points when starting orthok and delveloping an orthok practice and mind set.
Guidelines, Protocol, Informed Consent (Nikola Jagodic)
Orthokeratology Guidelines and Protocols like all other eye (health/medical) care specialties and sub-specialties guidelines and protocols are developed by the group of experts in the field according to the results of the evidence based medicine.
Wet lab, problem Solving (Caroline Guerrero Cauchi, Bruce Williams, Cary Herzberg)
A series of virtual orthoK patients will be presented. Case history will be reviewed for candidacy. Patient feedback, acuity, biomicroscopy and topopgrahy will be analyzed visit by visit. The changes and their outcomes made to the virtual patient’s treatment will be observed and discussed at each subsequent follow up visit.
Saturday, June 29th
Underlying Anatomical Changes in Orthokeratology (Helen Swarbrick)
This presentation will review the clinical and research evidence for our current understanding of corneal structural changes in orthokeratology (OK). Contrary to the concept that corneal topographic changes induced by OK are due to overall bending of the cornea, evidence continues to mount that OK achieves its effect solely by remodelling the anterior corneal surface, and in particular through epithelial thinning. In myopic OK epithelial thinning is central, whereas in hyperopic or presbyopic OK epithelial thinning occurs in an annulus in the mid-periphery. There is also some evidence of epithelial and/or stromal thickening in regions of the cornea vaulted by the OK lens. The clinical implications of these findings will be discussed.
The Optics of Orthokeratology - New Understandings (Pat Caroline)
The oblate shape of the cornea, following orthokeratology, results in unique corneal optics with negative attributes such as a small optical zone and high degrees of spherical aberration however, these attributes ultimately form the basis for the myopia controlling optics in children. Throughout this lecture we will review “the good, the bad and the ugly” of complex optics of the cornea following ortho-k.
Confocal Microscopy after Ortho-K (Amelia Nieto Bona)
Purpose: To assess long-term morphological and biometric corneal changes produced by overnight orthokeratology (OKN) and to examine their recovery after cessation of contact lens (CL) wear. To relate corneal reflectivity (backsccatter) of the image with corneal changes and visual quality obtained in each point time evaluated.
Methods: Prospective, single-center, longitudinal trial. The central cornea was examined using a confocal microscope and changes determined in visual acuity, straylight value and corneal haze. Cell counts and corneal reflectivity were performed using imageJ, software of the USA Health Institute. All measurements were made during 1 year orthokeratology treatment and 1 month after discontinuing CL wear.
Role of Cellular Biology in Understanding Ortho-K (Jennifer Choo)
The cornea is an extremely dynamic piece of tissue, it is constantly regenerating and adjusting to the stresses and pressures exerted on it through the ocular environment. Although most contact lens practitioners try to avoid inducing corneal changes with their lens fits, the goal of orthokeratologists is quite deliberately different. This lecture will review and summarize the numerous studies that have investigated the biological basis for the changes taking place within the cornea with OK to help the practitioner understand the procedure and ultimately help educate their patients.
Munnerlyn Formula: does it apply to Ortho-K (Andreas Berke)
Contrary to the incontrovertible practical success of Orthokeratology, there is still a lack of a self-consistent theory to describe the underlying biomechanical mechanisms of orthokeratology. A common accepted explanation of the Ortho K effects uses Munnerlyn’s formula to predict the change of dioptric power as a function of corneal respectively epithelial thinning. This formula primarily was used in refractive corneal surgery to predict the necessary depth of corneal ablation to obtain a required change of corneal dioptric power. A closer look to Munnerlyn's formula definitely shows that corneal thinning is the result of a reduction of corneal curvature. This could be caused by a shortening of the collagen fibres mainly in the anterior stroma
Evidence-Based Orthokeratology in High Myopia (Arthur Tung)
Innovative advances in Orthokeratology technology now make it possible for practitioners to treat extreme high Myopia. The most popular concern of molding higher myopia is “excessive central corneal epithelial thinning” as well as “central corneal erosion” accompanying the central compression force granted for reducing myopia -6 or above. We have to redirect the molding forces, for instance, to move tissues peripheral inward for relieving the inappropriate central forces and ensure the safety of high myopic molding. The wearing schedule, considering the excessive sagittal heights’ drop between zones and the requirement of water tight for effective peripheral inward molding, some strict rules should be advised to the patients for long-term safety.The longer course and smaller optical zone for high myopia molding is another concern that prohibits practitioners from entering the venture of high myopic molding. How can we mold them safely, efficiently and yet achieving acceptable optical zone width without too much glare? High myopia patients, though smaller in population, will be the most motivated candidates for Ortho-K if knowing how to handle the molding properly. They will also be the best patient source and free commercial for practitioners.
Customized Lens Design for the Average Practitioner (Jaume Pauné)
Current orthokeratology look for highest amount of myopia, astigmatism and hyperopia, as well post-lasik treatments. These are sometimes difficult or limited with the designs that companies provide to the customers. This is the reason by many optometrist starts to customize his lenses, looking out of the box the solution of common troubleshooting.
We have the possibility to use diverse software in order to achieve this. Mainly divided into keratometric and eccentricity values based (orthotools, GPEasy and RGP designer) or true topographic data based software (Wave and EyeSpace). All of them works on the basis of a tear layer profile.
What the trully importance is to understand the concepts of the forces acting on ortho-k and how to manage it. In this way, first is necessary to know it is the tear who does the moulding and for that we need a 360º alignment of the periphery of the lens. Second we avoid touch on apical portion of the cornea, is the tear and the pressure on the periphery who works on the moulding.
Finally, know with the custom lenses we are able to control the fit and solve many troubleshooting.
Correcting presbyopia with single vision Ortho-K lenses (Wolfgang Laubenbacher)
After 12 years of practice in Orthokeratology, many of my clients have become presbyopic. Without using special bifocal or multifocal Ortho-k lens designs, there are numerous ways to correct presbyopia with single vision Ortho-k lenses. Analysis of the individual visual tasks and demands of the customer leads to an individual determination of refractive values with and without an attached lens. Especially single vision Ortho-k lenses achieve a multifocal effect on the cornea, which will be presented here. Also how to manage presbyopic clients to obtain best results.
New Ortho-k Designs (Antonio Calossi)
Nowadays orthokeratology may be an effective procedure to treat a large spread of refractive errors.
It is an effective treatment for low to moderate myopia. Treatment of higher amount of myopia is achievable in selected cases. Treatment of astigmatism is possible with toric or bitoric designs. Treatment of hyperopia and presbyopia through corneal steepening is also promising. In selected cases we can extend the indication of reverse geometry lenses to correct irregular cornea such in keratoconus or keratectasia. With specific designs, is possible to enhance the correction of residual error after refractive surgery as PRK or LASIK.
Orthokeratology in the Netherlands (and beyond) – ‘say Cheese’! (Eef van der Worp)
This presentation will cover a retrospective view of the past 10 years from a Dutch perspective, as a little over years ago orthokeratology was reborn the way we know it today. I remember a road show in the fall of 2001 in the Netherlands at the introduction of this renewed modality that drew more than a thousand participants in what would possibly become one of the most exciting but also one of the most sensitive and even politically-charged introductions in the contact lens field to date. According to the latest Eurolens Research Survey, about 7% of all lens fits in the Netherlands today involve orthokeratology. Thousands of lens wearers in the Netherlands and around the world have been or are fitted with this modality, which is not only changing the way they see – for many it is changing their lifestyle and even dramatically changing their quality of life. What is the status of orthokeratology today –over 10 years after its rebirth? And what can we learn from the Dutch experience – both positive and negative.
Current Practice of Ortho-K in Oceania (John Mountford)
The practice of Ortho-K in Australia, South-East Asia and Hong Kong by optometrist will be discussed. Topics will include level of training, instrumentation, lens designs used and Ortho-K societies.
Ortho-K Research in China (Pei-Ying Xie)
Orthokeratology has been developed for more than 14 years in mainland China. There are more than one million wearers till now. Ortho-k lens is generally fitting for the lower myopia, astigmatism, anisometropia and amplyopia. Some special cases such as high myopia, high astigmatism, post corneal refractive surgery are also fitted. About 70% orthokeratology was driven by ophthalmologists, who have done many clinical researches, in the major hospitals. Researches mainly focus on long-term effects of myopia control; corneal thickness, endothelial and biomechanics changes induced by Ortho-k lens; comparison for peripheral retinal defocus of Ortho-k lens and various anti- myopia spectacles; visual quality and functions; as well as how to improve profession regulation by using electronic file and Internet support system.
Current Practice of Ortho-K in the Americas (Sami El Hage)
Orthokeratology was introduced in the USA by Dr. J. Ball in 1850, who patented the “Eye Cup” to flatten the cornea. He was followed by Dr. J. Stephens in 1865 that developed the “corneal restorer” and came up with the slogan “Spectacle rendered useless”.
With the discovery of PMMA and the development of corneal lens by Kevin Tuohy, Wesley & Jessen in the late 50’ and early 60’ started the first stage of modern Orthokeratology using a flat base curve and steep periphery. Four University studies results showed that OrthoK is safe and reversible, although, the FTC refuted their results.
New material of gas permeable contact lenses, along with, new reverse geometry design, opened the era of night wear of OrthoK lens, and hence, allowed patients to have functional vision throughout the day.
It has been a long way since the beginning of Orthokeratology, and the approval by the FDA of this new non-invasive keratorefractive procedure. This presentation will show the development of Orthokeratology in the US.
Sunday, June 30th
Relationship Between Ocular Imagery and Myopia Progression (Ian Flitcroft)
Animal, and more recently human studies, have revealed that the retinal image plays an important role in controlling eye growth and hence myopia. The concept of clinical refraction of the eye has historically been a purely paraaxial construct and hence also intrinsically foveocentric. It is now clear that the peripheral retina plays an important role in the regulation of eye growth. This has required consideration of the off-axis optical characteristics of the eye and renewed interest in issues such off-axis refraction, eye-shape and optical manipulations of the peripheral retinal image.
This presentation reviews evidence for the role of the peripheral retina in refractive development and demonstrates that equating off-axis refraction with off-axis retinal image defocus is erroneous. This is due to the impact of the dioptric structure of the local environment. In designing clinical studies it is important that all the principal variables in determining off-axis retinal defocus are controlled for. This will require including time spent in different dioptric environments as well as off-axis refraction.
Different Approaches to Myopia Control: where we are and where we go (Alessandro Fossetti)
Many methods have been advocated to control myopia, from visual training to undercorrection, from bifocals ophthalmic lenses to RGP contact lenses. Recently, orthokeratology and atropine have shown to be effective in slowing the progression of myopia.
The author talk about about the different approaches that have tried through time to reduce myopia progression, highlighting which of them can really work according to the most recent research, with some considerations about the perspectives of the new proposed method involving soft contact lenses with peripheral correction.
Myopia Control with Orthokeratology: Evidence and Possible Mechanisms (José Manuel Gonzalez-Meijome)
Higher myopic refractive error are associated with serious ocular complications that can put at risk the visual function. As a consequence there is an interest to slow-down and if possible stop myopia progression before it reaches pathological levels. A review has been done by searching in Pubmed database. The results from clinical trials evaluating the efficacy of orthokeratology to slow-down myopia progression based on axial length measurements as a primary outcome, and published in peer-review journals have been reviewed.
Orthokeratology has shown to be well accepted, consistent and safe method to address myopia retention in children. Orthokeratology is so far the method with the larger demonstrated efficacy in myopia retention across different ethnic groups.
Long-Term Effects on Myopia Control (Takahiro Hiraoka)
We conducted a 5-year prospective study to assess the long-term effect of overnight orthokeratology (OK) on axial length elongation in children, with those wearing spectacles as controls. Fifty-nine subjects were enrolled in this study. The OK group comprised 29 subjects who matched the inclusion criteria for OK. The control group comprised 30 subjects who also matched the inclusion criteria for OK but preferred spectacles for myopia correction. Axial length was periodically measured for 5 years and the time course of changes were evaluated and compared between groups. The results showed that axial length elongation during the 5-year study period was significantly smaller in the OK group than in the spectacle group. The current 5-year follow-up study indicated that OK can suppress axial length elongation in childhood myopia.
Information for Parents and Kids in Ortho-K (Michael Lipson)
This course provides helpful information for children and parents about Orthokeratology regarding safety, efficacy and expectations. It will detail how to explain to patients the improvement in unaided visual acuity, physical adaptation to the lenses and guidelines regarding wearing time and lens care. In addition, it will cover the vision-related quality of life factors involved in the process as well as information on myopia control with Orthokeratology.
Guideline and Informed Consent (Caroline Guerrero Cauchi)
This course dissects an orthoK informed-consent contract. Attendees will learn why a contract is so important, how it can protect the patient as well as the doctor and what items a well-constructed contract must contain.
Long-Term Clinical Success and Retention in Ortho-K (John Mountford)
There are two aspects to “retention”: firstly, the retention of the ortho-K effect and the associated regression during the post-wear period. Secondly, how many Ortho-K patients continue to wear their lenses and for how many years?
How to make patients love Ortho-K? Why is Ortho-K not popular as it should be? (Basil Bloom)
How to make patients love Orthok or Why is Othok not as popular as it should be.
How to build a successful Ortho-k Practice (Cary Herzberg)
If integrating corneal reshaping into your practice was as simple as stocking the latest new SCL design in your office there would be no need for this presentation. In fact starting or developing an OK practice requires new thinking in many areas including patient selection and management of office chair time. This presentation will cover the basic requirements that are necessary in order to successfully integrate Ortho-K into a practice setting.
Is Ortho-K a Successful Alternative for CL-Related Dryness and Discomfort? (Gonzalo Carracedo)
Between a 5% and a 20% of developed world population wears contact lenses. Still a significant number of them will give up wearing due to intolerance, being dry eyes one of the main reasons. Dry eye and alterations of the tear film in contact lens wearers are associated with reductions in functional visual acuity, reductions in wearing time, and an increased risk of ocular surface desiccation. Actually , the main indication of orthokeratology is the myopia control but also could be a good option for daily-wear contact lens wearers that relate dry eye symptoms at the end of the day, and they don't have a myopia progression.
In this talk we describe the different changes in tear film and ocular surface that are associated with dry eye in contact lens wearers and we will show results about signs and symptoms of dry eye during reverse geometry for orthokeratology worn overnight compared with daily-wear contact lens.
Inflammation and Infection in Ortho-K (Helen Swarbrick)
Almost ten years ago the orthokeratology (OK) community was rocked by a series of case reports of devastating corneal infections in patients wearing overnight OK lenses. These frightening reports threatened the future of the modality, with the implication that in some way OK was a dangerous and risky practice that had the potential to blind its users. Since that early crisis our appreciation of the safety and risks of OK has matured, and research has helped us to understand the context of the early series of case reports of microbial keratitis (MK) in OK. In this paper, we will review the current international situation in terms of safety of OK. The outcomes from clinical and laboratory-based research to investigate the relative risks of the OK modality will be summarized, and evidence-based strategies to minimize risk will be presented.
Ortho-K and Microbial Keratitis: an animal infection model (Jennifer Choo)
Microbial keratitis (MK) is the most serious complication of contact lens wear due to its potential to cause permanent vision loss. Many have speculated that manipulation of the corneal tissue with OK may make the cornea more susceptible to infection. Clinical and animal studies have suggested that the cornea undergoes changes to the epithelium and stroma with this procedure. The critical question is whether these changes to the normal corneal profile are predisposing the eye to an infection by compromising the cornea’s natural defensive barriers to microorganisms.
This lecture will explore this important issue through a review and summary of the clinical cases of infection reported and the animal studies conducted to investigate this issue.
How to manage Adverse Reactions (Nikola Jagodic)
We categorize the risks associated with ortho k contact lens wear according to: 1. contact lens design/manufacturing/material, 3. contact lens fit, 2. contact lens hygiene and wearing habits.
A red eye is hallmark for many of the different categories of adverse events that may occur in contact lens wear, but only one is vision (licence) taking - microbial keratitis