The results of the "Retardation of myopia in Orthokeratology" (ROMIO) study were published in October 2012 in the journal Investigative Ophthalmology and Visual Science. The study was a two-year randomized clinical trial by researchers at the School of Optometry at The Hong Kong Polytechnic University.
The goal of the study was to evaluate the effectiveness of orthokeratology (ortho-k) for myopic control in children.
The study examined 102 patients ranging in age from 6 to 10 years, with myopia between 0.50 and 4.00 diopters and astigmatism not more than 1.25 diopters, who were randomly assigned to wear overnight orthokeratology lens retainers or single-vision glasses for a period of 2 years. Axial length - a key measurement of myopia - was measured by intraocular lens calculation by a masked examiner. Measurements of the kids' eyes were taken at baseline and then every six months.
The researchers concluded that, on average, subjects wearing ortho-k lenses had a slower increase in axial elongation (a key marker of myopia progression) by 43% compared with that of subjects wearing single-vision glasses. The authors noted that younger children tended to have faster axial elongation and may benefit from early ortho-k treatment.
Experts estimate that 80% of learning is obtained through our visual system. That is why thorough eye exams and treatment for eye andvision problems are essential for academic and life success. Some vision problems can be treated with corrective lenses (glasses and contact lenses) while others that have to do with eye movement or the connection between the eyes and the brain require vision therapy - which is like physical therapy for the eyes and the brain and is delivered by a developmental optometrist like Dr. M.K Randhawa.
Just how important is vision for success? Here is what some scientists have found about the connection between vision and learning.
studies found significantly lower achievement test scores, as well as reduced letter and word recognition, receptive vocabulary, emergent orthography, and verbal and performance intelligence quotients among children with uncorrected hyperopia.
children with learning disabilities exhibit a greater prevalence of vision-related problems than the entire population.
most vision problems that may affect learning are related to refractive error, so vision examinations may provide helpful information in the management of children with learning disabilities.
Source:
Vision Problems of Children with Individualized Education Programs, Walline et al., Journal of Behavioral Optometry, Volume 23/2012/Number 4
The goal of the study authors was to describe the time course of changes in both peripheral refraction and corneal topography in myopic adults wearing myopic orthokeratology (OK) lenses. That means that the researchers wanted to to see how the surface of the cornea - the clear dome that covers the colored part of the eye - changed over time and whether the focusing power of a subject's peripheral vision changed overtime when overnight orthokeratology lens retainers were worn.
The study design was simple. Nineteen patients were fitted with ortho-k lenses and the researchers measured their peripheral focusing power and the contours of the surface of the cornea after 1, 4, 7 and 14 nights of ortho-k retainer lens wear.
The study reached the following conclusions:
Orthokeratology caused significant changes in both peripheral refraction and corneal topography. The greatest change in refraction and corneal refractive power across the horizontal corneal meridian occurred during the first night of OK lens wear. Subsequent changes in both peripheral refraction and corneal topography were less dramatic, in the same manner as reported changes in apical radius and central refraction after OK. This study confirms that with OK treatment, the peripheral retina experiences myopic defocus, which is conjectured to underlie the observed slowing of myopia progression.
The study adds to our understanding of the mechanism by which orthokeratology slows myopia progression. The culprit in myopia is thought to be focusing power in an eye's peripheral vision. This study explains how orthokeratology causes positive changes in this part of the eye that result in a slowing of myopia progression The role of the peripheral retinal in causing myopia progression may be difficult for the lay person to understand. One of the best explanations that we have read comes from the College of Optometrists in Vision Developmentblog post, "Its All About the Blur":
New theories on the development of myopia are evaluating the role of peripheral retina. When lenses are prescribed for any type of refractive error (myopia, hyperopia, astigmatism), those lenses put a clear and focused image on the fovea, which is essentially the “bullseye” on the retina. Whenever we want to see something clearly, we aim our eyes so the image falls on the fovea. The lenses allow us to see clearly precisely because the image is focused on the fovea. But those lenses (especially spectacles) have a different curvature than the retina. The result is a slight defocus on the peripheral retina. The further away from the central retina you are, the greater the amount of defocus. This is not something noticeable by the average patient, because the amount of blur is small, and because we don’t notice blur as well in the periphery. But it seems that our retinas DO notice, because there is significant evidence that this peripheral defocus drives the eye to elongate, and that elongation results in myopia.
Research published in the June issue of the Journal of Ophthalmology shows that Canadians are not taking easy steps to protect themselves against glaucoma. The study found that 50% of those who are newly diagnosed with the disease are already in the moderate to advanced stages of the disease. By this time they have suffered irreversible and often devastating vision loss.
Early detection is key because if caught early glaucoma can be managed and its progress halted. But there are virtually no symptoms in the early stages of the disease. That is why early detection is only possible through a complete eye exam by an optometrist or ophthalmologist.
The obvious implication of the study is that Canadians are not doing enough to protect themselves against glaucoma. Everyone should have an annual eye exam.
An article in the Toronto Star presented the following story that puts a human face on the tragedy that can occur if one ignores the need for eye exams as well as how fortunate you can be if you see your optometrist:
Keith Henderson, 62, a retired millwright in Alvinston, Ont., is fortunate. Ten years ago his brother was diagnosed with advanced glaucoma, which prompted Henderson to see an optometrist and request extra vigilance. Extra tests — which he had to pay for — showed he had high pressure. He eventually had prophylactic laser treatment to relieve the pressure.
“I won’t lose my eyesight to glaucoma because of what has been done,” says Henderson.
Henderson’s brother, Larry, now 65, is just about completely blind now, he says. The factory worker, was 55 when diagnosed, didn’t know to get regular exams.
“He didn’t get checked because he didn’t have coverage and then it started to get severe,” Henderson says. “They’ve got him as good as they could get him, but he’s lost a terrific amount of his vision.”
Diagnoses before there is vision loss is key. For patients, who catch it early and are diligent with treatment, vision can be preserved, Buys says.
Too many are doing it too late. “In a country that boasts of universal health care, our patients are coming in with already serious and significant loss of vision,” Hutnik says.
While we have a health care systems that calls itself "universal", eye exams are not covered. Yet, as the story above demonstrates, they are critical. The rationale for not insuring critical health services is often founded on the principle that people must have personal responsibility for their own health. For whatever reason - lack of knowledge, lack of resources, lack of awareness of what can go wrong with their health - too many people are not doing the right things. I hope some of them will read this blog post and make an appointment with their optometrist.
The risks of surgery pose a problem because vision therapy is a safe and effective non-surgical treatment for most types of strabismus, which makes most people think twice about surgery as a first choice treatment.
A famous case of vision therapy treatment for strabismus was the subject of the book Fixing My Gaze,an inspirational book by neuroscientist, Susan Barry, who was born with strabismus and had lived all her life without stereo vision, meaning that she could not see in three dimensions.
Even a single exposure to anesthesia during surgery is associated with developmental problems in children: new study
There is now new evidence that even a single exposure to anesthesia can be dangerous for a child. A study published in December 2012 in the journal Evidence Based Medicine found that children exposed to anaesthesia for surgery under 3 years of age were found to be at significantly increased risk for developing disabilities in receptive language, expressive language, total language and abstract reasoning at age 10.
The study authors commented that:
This study was the first to report the effects of anaesthetic exposure early in life on neuropsychological outcome using individually administered neurocognitive tests. Perhaps due to the greater sensitivity of these tests, Ing and colleagues observed disability even following a single exposure in early childhood, while several previous reports, utilising group-administered tests, had only detected learning abnormalities following multiple exposures.
This is the latest of 250 studies that have linked anesthesia exposure at a young age to brain development disorders. The previous studies found a link between anesthesia and learning disabilities in children who had two more more exposures to anesthesia, while the new study found a link in children with just one exposure. In the study's own words:
Thus far, more than 250 studies in immature animals have demonstrated that exposure to commonly used anaesthetics produces neuronal cell death, alters brain development and may lead to neurocognitive impairment. Similarly, in humans, an association between learning disabilities and two or more anaesthetic exposures has been observed in some studies, as most recently reported in children under 2 years of age.
Children who have strabismus surgery are risk of repeat surgeries, all of which carry the same risk. Eye surgeons often lament the need for repeat eye surgeries for strabismus patients. Surgeon, John W. Simon, notes that "patients must regularly contend with the unfortunate reality that even the most accurately planned and carefully executed surgery may not totally eliminate the deviation [i.e. the misalignment of the eyes] or completely normalize rotations. In addition, strabismus tends to recur over time." This limitation of surgery often results in the the patient being subjected to repeated surgeries - all of which may be unsuccessful. It is not uncommon for a patient to have had two or three or more surgeries and still have a noticeable misalignment or poor binocular vision together with depth perception problems or all three. For this reason, the surgeon's view is that "strabismus is less a problem to be cured than a problem to be controlled, with the minimum number of surgeries": Simon, John W. Complications of Strabismus Surgery. Current Opinion in Ophthalmology. 2010. 21: 361-366.
One study found that only 45% of children had successful alignment of the eyes at an eight-year follow up to their strabismus surgery. And while the low percentage was disappointing enough, 20% of the children had to undergo repeat strabismus surgeries which were ultimately unsuccessful: Awadein A, Sharma M, Bazemore MG, et al. Adjustable suture strabismus surgery in infants and children. J AAPOS 2008; 12:585–590.
Parents need to get the right information and ask the right questions
Parents of children with strabismus need to carefully evaluate the available treatment options. They should see a developmental optometrist like Dr. M.K. Randhawa to talk about whether vision therapy is effective for the type of strabismus that the child has. Parents contemplating surgery need to ask their surgeons about the risk of anesthesia exposure during surgery as well as all the other risks of strabismus surgery (ranging from death - a mortality rate of 1.1 per 10,000 cases is reported - scars, repeat surgeries, infections, lost muscles, vision loss, lack of depth perception).
Parents should consider vision therapy if their developmental optometrist thinks that vision therapy is appropriate for the type of strabismus that the child has. At our clinic, we have successfully treated dozens of strabismus patients, achieving straight eyes as well as functional binocular vision and depth perception and other developmental optometrists likely have similar results.
Here is a TED talk on vision therapy by neuroscientist, Dr. Susan Barry, author of Fixing my Gaze:
