Eye Didn't Know!

Chiropractic Pseudoscience

What's the rationale behind the chiropractic field?

It's easy to trace the hierarchy and progression of scientific ideas behind most medical science (just as it's easy to show that medicine was pretty primitive 100 years ago). 

Medical students learn the biology, physiology, biochemistry, anatomy, pharmacology, pathology, and so on, of human diseases. Treatment of these diseases is mostly based on evidence, the gold standard being the double-blind, controlled clinical trial.

Most physicians and most of the public have no idea what chiropractic treatment is based on, beyond a vague notion of spinal manipulation. Evidently chiropractors themselves split themselves into a wide number of camps, depending on their belief systems regarding how much spinal manipulation can affect physical conditions, and how widely they wish to wander into other areas of alternative (non-evidence based) care, such as acupuncture, herbs, homeopathy, etc.

Here is an excellent video designed to educate the public of the philosophy behind chiropractic care. What intrigues me is that it most resembles a pre-scientific, faith-based belief system, rather than a science. 

The video was made in response to the incredible lawsuit by the British Chiropractic Association against the free-speech rights of a British scientist, Simon Singh, who publicly criticized chiropractic. 

It is important that science be able to advance without being stifled by the legal intimidation of lawsuits such as this. It is also important that the public be made aware of the lack of a rational foundation behind practices such as homeopathy and chiropractic. (I'm not sure, though, if what most people believe is really guided by reason).

Luckily, few chiropractors, that I am aware of, make claims that spinal manipulation is effective in treating disorders of the eye. This may be, in my opinion, because most eye diseases have fairly objective measurements, such as visual acuity, refractive error, or intraocular pressure, which are measurable and less susceptible to the placebo effect, which is the only likely benefit of many non-scientific treatments.

There are many ways to treat physical conditions, but not all of them are based on reason or evidence. Caveat emptor.

Using Eyedrops

Did you know? Patients are routinely prescribed eyedrops for a variety of conditions, including dry eye, infections, glaucoma, and for post-operative care. Few patients, however, are given instructions on how to instill their eyedrops. When asked to demonstrate how they instill their drops, few patients are able to perform drop administration reliably, which means that they may be receiving inadequate medicine, or may be spending too much on drops because the drops don't enter the eye on first attempt.

The sketch below shows proper technique. One stands in front of the mirror, pulls the lower lid down, and places one drop into the pocket formed. The drop does not need to be placed on the eyeball, and one drop is all that is necessary.

That's all there is to it!

(image courtesy of American Academy of Ophthalmology)

Did you also know? Closing the eyes gently for a minute or two after drop instillation may help increase its absorption into the eyes and keeping the medication out of the bloodstream.

Summer Eye Safety

Did you know? With summer in full swing, it is important to emphasize the need for eye protection. I recommend a wide-brimmed hat and quality sunglasses whenever outdoors during the day. This could help prevent many eye conditions, including cataract (clouding of the natural lens within the eye), pterygium (a fleshy growth on the outside of the eye, common in outdoor workers), skin cancer (common on the eyelids and face), and possibly macular degeneration (a deterioration of the center of the retina, responsible for central vision.)

Did you also know? A hat and sunglasses will also protect against ultraviolet keratitis, a painful sunburn-like condition affecting the cornea from excessive sunlight while skiing or at the beach.

(image courtesy wikimedia commons)

Orthokeratology: new and improved?

Did you know? Orthokeratology, or changing the refraction of the eye by overnight use of rigid contact lenses, is making a resurgence under the name of Corneal Refractive Therapy, or CRT.

Recently a friend of mine asked me about its efficacy in children. He was concerned that his daughter’s mild myopia would continue to progress. Since orthokeratology is not used by the vast majority of ophthalmologists, I could not immediately answer his question.

It so happens that the lead article and editorial in the May 2007 issue of Archives of Ophthalmology were about the dangers of orthokeratology! A study from Taiwan, (where myopia is extremely common and the interest in orthokeratology has grown), reported the risk factors for microbial keratitis, or corneal ulcers, which are serious and potentially sight-threatening infections of the cornea, the clear front surface of the eye. A major risk factor was orthokeratology. The authors stated that this risk was:

“...worthy of special attention given the increased popularity of overnight orthokeratology. Eye care practitioners who perform overnight orthokeratology have an obligation to warn their patients of this potential vision-threatening complication...”

The journal’s editors stated:

"The rationale for the ongoing use of overnight orthokeratology in the pediatric and adolescent population is therefore brought into question. Although these techniques can rapidly and effectively reduce myopia, albeit with limited range, accuracy, and precision... complete or near complete regression of effect is the rule, and this technique has not been demonstrated to have any infulence on mypopia progression due to [lengthening of the eye]."

In other words, orthokeratology temporarily reduces myopia, with limited precision, presents a risk of serious infection, and does nothing to reduce progression of near-sightedness.

Parents considering orthokeratology for their children should heed the messages in this article.

Furthermore, it should be pointed out that if you use orthokeratology, every time you stop wearing your overnight lenses, your refraction will be shifting, so that backup glasses will not be useful!

Did you also know? Parents should realize that by the time their children are adults, the science of refractive surgery will be even further refined, safe, predictable, and permanent, which cannot be said of orthokeratology, despite its appeal of being non-surgical.

New use for old Chinese remedy?

Did you know? A synthetic version of bear bile, used in Chinese medicine for millenia, is being tested for its ability to prevent cell death which occurs in macular degeneration, glaucoma, and retinitis pigmentosa. TUDCA and UDCA are components of bile, which help us digest fats. Humans have small amounts of these compounds, but bear bile has large amounts. Synthetic versions are available and inexpensive. Researchers at Emory University tested these compounds. When injected into mice, they preserved the function and structure of retinal cells in two different mouse models of human retinal degeneration. Read about it here.

Did you also know? The researchers stress that the compounds they are testing are synthetic, and do not involve harvesting bear bile! In fact, UDCA, or ursodiol, is available orally as a treatment for liver disease.

More itchy eyes

Did you know? No sooner did I write about Zaditor being available over-the-counter for treatment of allergic eyes, then I learned that Bausch and Lomb is marketing the same medication (ketotifen fumarate) as a drop called Alaway. Alaway, according to the company, is available in a larger bottle and is thus more economical.

Did you also know? For mild allergic eyes, a simple cold compress (a cool washcloth) or artificial tears will soothe the eyes without the need for stronger, more expensive medicine. Most ophthalmologists do not recommend over-the-counter eyedrops that "get the red out" because they tend to have a rebound effect.

Itchy Eyes?

Did you know? With springtime approaching (and with Santa Ana winds blowing in my part of the country) itchy, allergic eyes are a frequent complaint. A prescription strength eyedrop is now available over the counter to help with this condition. Zaditor (ketotifen fumarate) is a type of antihistamine and mast-cell blocker which is very effective in decreasing ocular itching from allergies. It is similar to Patanol, which I have prescribed for many years. Now available over the counter, it brings more effective relief than any of the myriad of ineffective products now marketed for ocular allergy.

There are many causes of red, itchy eyes. Allergy is just one. A visit to an ophthalmologist will tell what the cause is.

Did you also know? Antihistamine pills (like Benadryl or Claratin) can make eye allergies worse. These pills frequently cause dry eyes, which can worsen irritated eyes.

Purrfecting artificial vision?

Did you know? Since I began practicing ophthalmology, on a regular basis someone will ask me when will we have an artificial eye, or an eye transplant, or at least an artificial retina. A cute abyssinian cat with a blinding eye disease may help. A condition very similar to retinitis pigmentosa has been found in these cats, and a researcher in Missouri is implanting a 2mm wide electronic chip into their retinas. It is too early to know whether these chips are helping or whether they will provide humans with useful vision. (There are a handful of humans with similar implanted chips).

Did you also know? Dr. Kristina Narfstrom has studied these cats for 20 years. This webpage shows pictures of the diseased cat's retina, and the interesting way she uses an electroretinogram (an ERG is like an EKG of the retina) to quantify the cat's visual loss.

Rosacea

Did you know? Rosacea is one of the most common reasons for red, irritated eyes. Rosacea is a common condition that causes redness of the nose and cheeks. It is caused by inflamed, dilated small blood vessels in the skin. It is very common among those of northern European heritage, especially the Irish and Scottish. It is sometimes worsened by alcohol, caffeine, and some foods. With rosacea, the oils secreted by the eyelids are abnormally thick and irritating, causing redness and discomfort. This is termed blepharitis. Often styes result from plugged glands. The standard treatment for this disorder when it involves the eyes is doxycycline or minocycline. These pills, related to tetracycline, are thought to decrease the inflammatory nature of the secreted oils. Warm soaks are essential, too.

Did you also know? Many doctors believe that fish or flaxseed oil supplements, such as Theratears Nutrition, may help with this condition. I would like to see more controlled studies verifying this claim.

Visual Migraines

Did you know? Many people occasionally suffer from the visual phenomena of migraines without the accompanying headache? These phenomena often take the form of jagged, or zig-zag lines, sparkling lights, or prismatic effects. They usually last about 20 minutes or so, and can be accompanied by a blind spot. If someone has one for the first time, it can be quite unnerving, and often I see patients in my office describing these symptoms. As long as they don’t suddenly increase in frequency, they rarely indicate more serious medical problems.

Did you also know? Since at least the middles ages, artists have recorded the visual effects of migraines. Recently, art competitions have emerged to give modern-day artists an outlet for their migraine-inspired artwork.