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What is “Core” Eye Testing?
Lori wrote:
I work for the Foundation Fighting Blindness a charity that raises money for retinal disease, and as such take calls from people with questions about research. I recently had a call from a woman, asking about standards in optometry practice. She is concerned about a variety of new testing technology being offered by her optometrist and how much is really necessary. She doesn't feel she can ask him what is "core" - needed testing - and what is extra and she doesn't know where to turn to find out about such standards. I clearly need to refer her to somewhere but where? Thanks.
Dr Henry Smit's response:
Dear Lori:
Firstly, I would like to say thank you for the work of the Foundation Fighting Blindness. Many patients have benefitted from the results of retinal research that your foundation has supported. I wish you and your organization every success in your future endeavours.
Your client’s question about what is “core” testing and what is “extra” has a somewhat complicated answer, and I apologize in advance for this lengthy response.
Optometry, like medicine and other health care professions, is governed by provincial legislation. In each province, there is an Optometry Act which outlines, in rather broad strokes, how the profession is to be practiced in that province. In addition, there is normally a set of regulations which define more clearly how the Act is to be implemented in the day to day practice of the doctors. The regulations stipulate that the doctor has to meet the standards of practice for the profession, and when he or she fails to do so, the practitioner becomes subject to disciplinary action.
The standards of practice for optometry (and other health professionals) are developed within the profession and typically define a “minimum” standard that the practitioner has to meet in his or her encounters with patients. These standards are constantly evolving as new understanding and technology are developed. Regulated standards of practice do not set the bar at a standard of “excellence”, or even “preferred practice”. They often lag behind what many of the keen practitioners in the profession have set for themselves. In other words, if all practitioners in a profession practiced only to the regulated standard of practice (a minimum standard, which if not met would result in disciplinary action) the average level of care provided by the doctors would be less than it is actually is.
I have often remarked that, if I practiced now as I did when I entered practice over thirty years ago, I would be guilty of not meeting the standard of practice that is expected of me today. Conversely, if I practiced then as I now practice, I would have been breaking the regulations that existed at that time. For instance, when I entered practice I was forbidden by the Optometry Act that was in existence in my province at the time, to apply a drop of topical anaesthetic in the eye in order to measure the patient’s intraocular pressure as part of my screening for glaucoma. Today, if I do not measure intraocular pressure, I fail to meet the current standard of practice.
Further, as an example of how this evolution of standards is ongoing, we now know that the thickness of the cornea has a much greater influence on intraocular pressure measurements than doctors previously understood. When a patient’s cornea is thinner than average, our clinical instruments that measure intraocular pressure are fooled into thinking that the pressure is lower than it actually is. If the patient has a thicker than average corneal thickness, then the instruments are fooled into thinking that the pressure is actually higher than it is. As a result, in the past there were probably many patients who were unnecessarily treated with pressure lowering medication, because they had a thicker than normal cornea and the standard intraocular pressure measurements incorrectly indicated that the pressure was elevated. On the other hand, and more seriously, there were many patients with thinner than average corneas whose intraocular pressures measured in the normal range, but who actually were at a high risk of suffering vision loss due to glaucoma. Once this relationship between intraocular pressure measurement and corneal thickness was well established, in my own practice, we invested in several instruments (pachymeters) to measure a patient’s corneal thickness, so that the doctors in my practice would have a better understanding of the patient’s actual intraocular pressure and risk for developing glaucoma. It is now the “standard of care” in my practice to measure the corneal thickness on all adult patients. However, the regulated standard of care does not require our doctors to take this measurement. We do it in our practice because we know that, if we practice only to the regulated standard of care, too many of our patients will be misdiagnosed and their visual outcomes will suffer. The regulated standard of care might consider pachymetry to be “extra”, but in our office, we consider it an essential test – a part of our core testing.
Like the Foundation for Fighting Blindness, optometrists are very concerned about fighting blindness and keeping their patients healthy. It is especially discouraging for me that so many of the patients who seek vision rehabilitative services from organizations such as the CNIB, are suffering from vision loss that was preventable, if the disease process had been detected and treated earlier. In many cases, it is the “extra” testing that newer technology has made possible that brings disease processes to light earlier and improves the visual outcome for the patient. In many cases what is considered “extra” today evolves into tomorrow’s minimum standard of care.
To sum up, there are minimum “standards of care” established by the regulatory body of each provincial health profession. These regulatory bodies are usually called “colleges”, such as the College of Optometry (for optometry) or the College of Physicians and Surgeons (for medicine). If your inquirer would like to know what the regulated standard of care is, then she could approach the college of optometry in her province to find out what minimum core testing is required. It is my hope, however, that she is being looked after by a practitioner who provides care beyond the minimum that is legally required.
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