September 2018


Prolonged reading shows negative effect on tear film and ocular surface

by Liz Hillman EyeWorld Senior Staff Writer

Research suggests conducting reading tests could reduce discordance between patient-reported symptoms and clinical exam findings

When it comes to dry eye and ocular surface disease, there is often discordance between what the patient describes and what the clinician sees upon examination, said Esen Akpek, MD, Bendann Family Professor of Ophthalmology, Wilmer Eye Institute, Baltimore.
A patient with dry eye might come into the clinic miserable, complaining of being unable to see, unable to read, avoiding night driving or driving in unfamiliar areas due to fluctuating vision symptoms. Yet their exam shows a visual acuity of 20/20 and their ocular surface looks fine at the time. On the flip side, a patient undergoing therapy for dry eye might come in for a checkup, praising the treatment and how it has helped them, but their ocular surface, upon clinical examination, looks terrible.
Wanting to better understand what could be going on in situations like these, Dr. Akpek and her team began testing visual function in dry eye. First, they used existing reading tests, the majority of which are short in duration and designed for patients with central visual acuity issues, and found there wasn’t much of a difference between those with dry eye and age-matched controls.
“Then it occurred to us that maybe … [patients with dry eye] can’t sustain reading. Book reading is not only for 2 minutes. When you have an interesting book, you sometimes read it for hours, and some people make a living reading, doing computer work and using their eyes in a sustained manner. We thought maybe the testings are not long enough,” Dr. Akpek said.
In a paper published in Ophthalmology, Dr. Akpek and her colleagues describe using a 30-minute silent reading test of 7,200 words, which was developed by Pradeep Ramulu, MD, PhD.1
“When we used the sustained reading testing, we demonstrated that these patients with dry eye read less words per minute, and it gets slower toward the end of the reading test,” Dr. Akpek said.
The researchers used the Ocular Surface Disease Index questionnaire, conducted noninvasive tear breakup time testing, analyzed surface asymmetry and regularity of indices, and performed Schirmer’s testing without anesthesia, corneal staining with fluorescein, and conjunctival staining with lissamine green both before and after the reading test. All of the testing measures, except the surface asymmetry index, were worse in the 177 dry eye patients who participated as well as in the 34 normal controls, all of whom were 50 years or older.
“Reading disturbs the eye surface. It dries it up and increases the surface staining scoring. That causes irregularity of the eye surface and the tear film and probably blurring of the image,” Dr. Akpek said.
Dr. Akpek and coinvestigators are conducting further research to find out why prolonged reading seems to have this effect on the ocular surface and how it translates to changes in visual function. They also seek to answer questions like what would happen if the visually focused activity is even longer or if a short break can act as a recovery period.
“Is it the blinking rate? Is it evaporation? Maybe it’s the blurring of the vision because of the fast tear film breakup time because the tears are unstable. … We are in the process of measuring all these parameters and analyzing the tear film before, after, and during reading, to see what’s actually happening,” Dr. Akpek said.
Dr. Akpek said this research is important, especially in an age where reading and screen time is so prevalent. According to the U.S. Bureau of Labor Statistics’ last survey regarding computer use at work in 2005, 55.5% of the employed populace used a computer.2 One can surmise that percentage would be higher if the same survey was conducted today. More recent statistics from the American Time Use Survey found that men spent, on average, 0.25 hours a day reading for leisure while women spent 0.33 hours a day. Watching television was 2.94 hours and 2.5 hours for men and women, respectively, and playing games and computer use was 0.49 hours and 0.34 hours for men and women, respectively.3 A Common Sense Media survey of more than 1,700 parents found they spend, on average, 9 hours and 22 minutes using a screen of some sort every day.4
“We don’t take care of our eyes,” Dr. Akpek said. “We need to understand why we get dry eye as we get older and we need to be able to take care of it before it happens.” She likened the preventative measures that she thinks should happen in eye care to the preventative measures dentistry began instituting to improve oral health decades ago.
Based on this latest research, Dr. Akpek said clinicians should realize that what patients describe and what providers see on clinical examination might not match. As such, she and her coauthors suggest stressing the surface of the eye, perhaps with prolonged reading as described in their research, to better simulate the conditions a patient might experience through the day.
“It’s like a stress test for angina. You examine the patient at rest, but you can’t diagnose angina … if you don’t do the stress test for the heart. You have to catch it right there during the exercising,” Dr. Akpek explained. “We have to listen to our patients, understand what it is that they are talking about. We have to learn how to take care of the eyes, know why we get dry eye, and how not to get dry eye.”


1. Karakus S, et al. Effects of prolonged reading on dry eye. Ophthalmology. 2018. Epub ahead of print.
2. U.S. Bureau of Labor Statistics. Computer and internet use at work summary. Economic News Release. August 2005.
3. U.S. Bureau of Labor Statistics. American Time Use Survey – 2017 Results. June 2018.
4. Common Sense Media. New report: parents spend more than nine hours a day with screen media. December 2016.

Editors’ note: Dr. Akpek has no financial interests related to her comments.

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