Ortho-K
History of ortho-K
It is believed the ancient Chinese placed tea bags filled with sand on the closed eyelids during sleep to improve vision in people with short sight thousands of years ago.
In the 1960s, some optometrists noted that certain rigid contact lens wearers experienced improved eyesight after removing their rigid lenses, and began to explore the use of rigid contact lenses for improving sight, which has led to modern day orthokeratology (ortho-K).
Ortho-K today
Technology has brought ortho-K into modern clinical practice. Key advances include:
Computer assisted measurement of the curvature of the eye, known as corneal topography or mapping
Computer assisted lens design and manufacture for precise production of complex shapes and lens designs that greatly enhances centration and stability of the treatment
Highly oxygen permeable treatment lens materials that enable safe overnight wear.
Today, ortho-K is an ideal treatment for those with appropriate prescriptions who wish to see clearly without the inconvenience of spectacles and day time contact lenses and are apprehensive about the risks associated with laser eye surgery.
Children and teens
Ortho-K is arguably the treatment of choice for suitable children with progressive myopia (short-sightedness). Age is not a key determinant of suitability.
Our patients are instructed to be fully independent with all lens care procedures including insertion and removal of lenses onto the eye. We have a very high success rate with our patients despite age.
In cases where the child is not yet ready to learn to manage the contact lenses themselves, we can teach parents to aid in the process until the child is more confident.
Myopia control
Myopia is now becoming a fast growing epidemic around the world, with prevalence of myopia up to 98% in some countries, and even up to 50% of the Australian population. Myopia occurs due to elongation of the eye, which causes distant objects to become defocussed. As the level of myopia increases, patients experience blurrier vision and become more dependent on spectacles or contact lenses for sight. As myopia progresses, patients need to keep updating their prescription lenses, which is expensive especially with high prescriptions.
This can be worrying for patients and parents not just in terms of inconvenience and monetary costs. As the degree of myopia increases, so does the risk of eye disease such as myopic maculopathy, retinal detachment, cataracts and glaucoma.
Due to the health and economic burden myopia poses to society, much research is being conducted in the prevention and control of myopia. At Eyetech, Dr. Russell Lowe and Dr. Laura Downie have published a retrospective clinical study based on the past 8 years of experience in treating children with ortho-K here at eyetech. Known as the 'CRIMPS' study (Corneal Reshaping Influences Myopia Prescription Stability), this work reveals strong evidence that ortho-K acts to slow myopia progression and stabilise eyesight.
We are confident that our Clear Vision Corneal Reshaping Program will inhibit myopia progression for the majority of our young patients, depending on suitability for treatment.
How does ortho-K work?
Ortho-K utilizes precisely the same principle for restoring clear unaided eyesight as laser refractive surgery, that is the front curvature of the eye is flattened across the pupil to refocus the image back onto the retina.
During sleep the ortho-K reshaping lens rests gently on the surface of the eye supported by a thin film of tear fluid. The lens generates positive (pushing) and negative (pulling) forces in the tear film responsible for creating the new corneal shape.
Changes in the corneal shape can usually be measured within fifteen minutes. The process builds with each night of treatment and usually requires 1-2 weeks to fully restore vision.
Safety of ortho-K
Ortho-K has an outstanding safety record where treatments are prescribed by certified practitioners in a well-organised clinical setting where patients have access to regular follow up care.
No adverse long-term effects have been reported in the medical literature.
There are, however, a number of alarming reports of eye infection (microbial keratitis) in children treated with ortho-K. The majority of these occured around the year 2000 and were related to substandard levels of patient care in unregulated markets including the use of inappropriate cleaning and lens care solutions.
The ongoing health and safety of your and/or your child's eyes is our greatest concern, and we strive to ensure the highest level of clinical care. Our safety message begins before treatment commences by asking you to sign an informed consent form that outlines your ongoing responsibility for lens care and hygiene under the program.
Suitability for treatment
Before offering you an ortho-K treatment program, we must determine your suitability for treatment. This involves a thorough eye examination to confirm the target refraction, the health of your eyes and the pre-treatment corneal curvatures. Then follows a fitting appointment where treatment lenses are carefully evaluated on your eyes. Once this process is complete, you will receive your own prescription pair of highly customized ortho-K lenses for your first overnight wear and for ongoing use as directed.
Other myopia treatments
More than ever before, vision scientists are focusing attention on methods for prevention rather than simple correction of myopia in young eyes.
We watch with interest as other promising new technologies emerge, including a novel spectacle lens design, a low dose anti-muscarinic eye drop with minimal side-effects and a new soft bifocal disposable lens that is performing well in clinical trials and is expected to be released before long.
Age is no barrier
Ortho-K works well for suitable candidates of all ages. A number of our corneal reshaping patients commenced treatment in their fifties and sixties. The reason for the broad success of this modality across all age groups lies in the fact that ortho-K alters only the outer layer of the cornea, known as the epithelium or 'skin layer'. The epithelium is a unique tissue - it is constantly renewed every 10-14 days. So in other words, the corneal epithelium remains young throughout life.