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Many people complain of eye problems their doctors miss during eye exams. A recent article in JAMA Ophthalmology explains the reasons why.

Many people, as many as half of all patients of ophthalmologists and optometrists, don't get the glasses or other vision correction they need because their doctors miss common problems during eye exams. The problem is especially common in eye patients who have past the age of 55, and in eye patients who have glaucoma, the condition of acute or chronic elevated intraocular pressure that can lead to vision problems and blindness.

Lighting Makes a Big Difference in Vision Testing

Dr. Anjali Bhorade led a team of researchers at Washington University School of Medicine in St. Louis, Missouri. Between 2005 and 2009, she and her colleagues followed 175 patients over the age of 55, including 126 who had glaucoma.

Volunteers for the study got eye exams at the university clinic and were also visited by occupational therapists in their homes. The researchers tested their patients' ability to read the standard eye chart at a distance and at arm's length. They tested their ability to see light and dark. In addition to testing their vision at home, the researchers also measured light levels.

Bhorade and her team expected people to test better at the doctor's office than at home, but they were surprised that 

more than 50 percent of patients did better on tests at the doctor's office than at home. The differences between test results were greater for the patients who had the worst cases of glaucoma.

And what was it about the doctor's office that made such a huge difference in how well patients could see? Lighting levels, it turned out, were 3 to 4 times greater at the doctor's office than in the patients' homes.

Doctors Need to Listen to Patient Complaints

Dr. Bhorade stated that the take away from the study was that doctors need to listen to their patients' complaints about eye problems. A doctor may dismiss a patient complaint when treatment is actually needed, because the doctor's office is better lit. 

In the management of glaucoma, the doctor's treatment recommendations are usually based on readings intraocular pressure taken with a device called a tonometer, and they doctor's visual inspection of the optic nerve. In the management of cataracts, however, eye tests make the critical difference.

Cataracts are not treated until they are "ripe," that is, until the cataract causes enough vision loss that the patient cannot read better than 20/200 on the vision chart.

In the United States, this is the definition of legal blindness. Cloudy vision, blurry vision, difficulty driving at night, sensitivity to glare, inability to see in bright sunlight, difficulty reading black type on white paper, double vision, or loss of the ability to see bright colors simply are not enough to qualify for cataract surgery. Only "flunking the test" qualifies the patient for the simple and usually successful surgery. 

However, if someone who has cataracts is tested at home, there is a much greater likelihood of qualifying for surgery that restores sight.

Bhorade and her collaborators suggest that at-home testing of cataract patients may reveal that many more patients than doctors realize need cataract treatment now.

Other Examples Of The "White Coat Effect"

Cataracts and glaucoma are not the only health problems that test differently at the doctor's office. There are countless other conditions that exhibit some kind of white coat effect, the body's reaction to the presence of a doctor.

The white coat effect is named after the expectation, at least in North America, that doctors are "supposed" to wear white coats. When doctors come in to see their patients without their white coats, even if it is to minimize the transfer of microorganisms from one exam room to the next, patients are less comfortable and less confident in the doctor. 

While the white coat increases confidence in the doctor, it also increases expectation of receiving an unfavorable diagnosis.

The most famous example of the "white coat effect" is blood pressure. Most people have higher blood pressure when their pressure is measured by a doctor in a white coat. As a result, some researchers believe, doctors tend to hand out too many prescriptions for high blood pressure medicine. Other conditions that show a similar effect include:

  • Allergies. People who expect to test positive for allergens sometimes develop a reaction to the test before it is given.
  • Hearing loss. Patients who expect to be found to have hearing loss are less likely to hear tones.
  • Muscle weakness. Patients who believe they will be told they have suffered a stroke on one side of the brain may experience loss of muscle tone on one side of the body, and not necessarily the side of the body that would become weak due to the stroke they think they may have had.
  • Stomach aches. Particularly in children who are bullied by other children, the expectation of having a stomach will produce a stomach ache.

In fact, for abdominal pain, chest pain, cough, constipation, dizziness, fainting, insomnia, numbness, shortness of breath, tingling, and unexpected weight loss, the body behaves differently once you get in to see the doctor, and a physical cause cannot be found nearly 85% of the time. That doesn't mean that the correct diagnosis is "it's all in your head." Some symptoms are simply vague, and they tend to appear when they are expected. They may actually have a physical cause that the doctor cannot determine. Or they may be psychosomatic. The doctor simply cannot find out even with an investment in expensive medical tests and a great deal of the doctor's time.

Some conditions will disappear at the doctor's office under the same circumstances.

Vision problems, on the other hand, seem to display the opposite of the white coat effect.
Your vision will tend to be better at the doctor's office, especially if you go to the optometrist or ophthalmologist so often that you know the eye chart by heart. If you or a family member has any vision problem that can be corrected or controlled, ask your doctor about testing in low-light conditions that similar to the level of light encountered day by day.
Making allowance for the excellent lighting of the eye doctor's office may make the critical difference in getting needed care for cataracts and glaucoma.
Read full article

  • Bhorade AM, Perlmutter MS, Wilson B, Kambarian J, Chang S, Pekmezci M, Gordon M. Differences in Vision Between Clinic and Home and the Effect of Lighting in Older Adults With and Without Glaucoma. JAMA Ophthalmol. 2013 Nov 21. doi: 10.1001/jamaophthalmol.2013.4995. [Epub ahead of print]
  • Landry M, Dornelles AC, Hayek G, Deichmann RE. Patient Preferences for Doctor Attire: The White Coat's Place in the Medical Profession. Ochsner J. 2013 Fall. 13(3):334-42.
  • Photo courtesy of Focus Clinics by Flickr :
  • Photo courtesy of Carl Bednorz by Flickr :

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