PERSONAL HEALTH : When It’s All a Blur : New Developments in Equipment, Lighting and Prescriptions May Help Ease Strain of Staring at VDTs

When UC Berkeley optometrist James Sheedy opened the first eye clinic to study how working at a video display terminal affects vision, a nagging question soon arose.

Even in the early 1980s, Sheedy was seeing thousands of patients yearly with VDT-related eye problems. Was he attracting all the patients who had this problem because of his specialty? Or were other eye doctors seeing a high percentage of patients with VDT-related problems too?

After more than a decade of concern, that question has finally been resolved. Vision problems, Sheedy found in a nationwide survey, are one of the biggest physical complaints related to VDT use, far outpacing repeated trauma disorders such as carpal tunnel syndrome. Thus, these complaints are a major source of American workers’ on-the-job discomfort, leading to decreased productivity and poor performance.

About 10 million Americans suffer from VDT-related vision problems, based on the survey of 1,307 optometrists, Sheedy says. He found that 14% of those who go for an eye exam do so primarily because of symptoms related to VDT use.

“This study confirms that computers bring out the worst in our eyes,” says optometrist Jay Schlanger, a VDT expert who practices at Cedars-Sinai Medical Clinic in Los Angeles. “The more you use computers, the more stressed your eyes get.”

Proof that computers can affect vision is leading to significant changes in the workplace, including more sophisticated computers and accessories, ergonomic changes and insurance plans that allow for special prescriptions for VDT use.

Anyone working on a computer more than two hours a day is at risk for vision problems, Sheedy cautions. He estimates that three-quarters of all people who work extensively at VDTs have occasional symptoms.

The major complaints, according to the survey, are eyestrain, headaches, blurred vision, dry or irritated eyes, neck or back aches, photophobia (sensitivity to light), double vision and afterimages.

“These symptoms occur when the visual demands of the task exceed the visual abilities of the individual. So everyone has a breaking point,” Sheedy says.

Other symptoms include blurred distance vision and crossed eyes.

“There are quite a few people who have difficulty maintaining alignment of the eyes,” Sheedy says. “The eyes want to cross or diverge too much. That is a condition that might not manifest itself if you were not working at a VDT.”

Some people also experience the temporary “McCullogh effect,” in which white objects appear pink after VDT use. This usually clears up in minutes.

The biggest concern, however, is whether computer work can cause permanent vision changes. In Sheedy’s survey, published last October in the Journal of the American Optometric Assn., a majority of the patients (63%) said they had needed prescription eyeglasses to relieve symptoms. But in most of those people, Sheedy says, computers have simply magnified problems that would have occurred regardless of the individual’s work.

Nonetheless, other studies have also shown that some people may develop permanent vision changes solely because of VDT work.

“There is very good scientific evidence today that doing extended near-work can result in a small degree of myopia in adults,” Sheedy says, but “we can’t predict who will develop it.”

Many people suspect that their computer work causes their vision problems. “People will say, ‘I’m fine at the beginning of the week, but I’m dead meat by Thursday; I’m fine going into work, but I can’t see a thing driving home in the evening,’ ” says Florida optometrist Lowell Glatt, a member of the American Optometric Assn.’s commission on standards.

The good news is that alleviating most VDT-related eye problems is usually not difficult.

“There is a myth that there is something spooky coming from the VDT that is causing eye trouble. But a lot of these symptoms are quite explainable,” Sheedy says.

In the recent survey, the biggest environmental causes of eye problems were screen glare, work arrangements, incorrect lighting and screen resolution.

Glare is produced when bright lights reflect on the computer screen, washing out the resolution of the characters and forcing the eyes wider, says Rolland VanStroh, marketing manager for the Glare/Guard division of Optical Coating Laboratory in Santa Rosa. The lab produces a screen filter that recently won the American Optometric Assn.’s first seal of acceptance for VDT products.

Many employees find such filters significantly ease their eye strain. But blocking light sources also helps.

Sheedy suggests this test to see if overhead lights are too bright: Look straight across the room. Put your hand up to block the overhead lights from your field of vision, like a sun visor. If you feel your eyes relaxing, the lights are too strong.

“Unless the office was specifically designed for computer use, you typically have 25% more light than you need most of the time,” Glatt says.

Screen color and resolution, if poor, produce many eye problems, Sheedy says. For example, a low-quality computer with a black background is usually problematic.

“The problem with a dark background is you are looking at a black hole surrounded by a bright environment. Everything should be fairly close in brightness,” Sheedy says.

Good posture helps too: The screen should be 15 to 20 degrees below eye level because, Sheedy says, “our eyes work best looking slightly downward.”

Looking away from the screen for a few seconds and blinking slowly several times also relieves dry, sore eyes. In particular, people who wear contact lenses blink much less while working on VDTs.

Beyond environmental changes, people who work on computers all day may also need prescription eyewear.

“More and more people are getting just computer glasses because of the strain,” Schlanger says. “Our eyes are not made to look at a computer all day long--that close, that intense and not blinking.

“Many people who would not normally need a prescription can find a significant improvement with their computer when they use a prescription.”

Moreover, VDT workers who wear bifocals often have neck strain or backaches because bifocals are usually designed for a reading distance of 16 inches at an angle of about 25 degrees downward, while a computer screen is usually 20 to 24 inches away and about 10 degrees downward. One option for bifocal wearers is a separate prescription for computer use or a continuous-curve bifocal lens that can adjust to all demands.

Meanwhile, employers seem to be willing to pay for more VDT-related eye problems, experts say.

“There is a growing interest in eye-care plans because companies are recognizing that this is not a real costly benefit and it’s going to help people on the job,” says Charlotte Rancilio, a spokeswoman for the American Optometric Assn.

Some companies are offering special VDT-vision exams in addition to regular vision insurance. And almost all companies endorse the idea of good ergonomics.

“The employer has to be involved to some extent,” Sheedy says. “You can’t count on employees to self-diagnose.”

Eye doctors are joining the efforts to improve workplace vision. A few have opened VDT-vision clinics such as Sheedy’s, and some are prescribing computer screen filters or setting up mock workstations in their offices to help diagnose patients.

Says VanStroh: “Doctors are becoming much more sophisticated about this issue.”

Reducing Computer Vision Syndrome Vision problems tied to heavy computer use affect as many as 10 million Americans. Most symptoms--including dry eyes, blurred vision and headache--are temporary and easily corrected. Here are some steps that can be taken to improve your workstation: 1. Use a glass or high-quality plastic filter. Avoid mesh or cloth filters. 2. Use a document holder placed close to the screen. 3. The screen should be about 20 degrees below eye level. 4. The screen should be 16 to 30 inches from your eyes. 5. Avoid bright overhead lights, especially fluorescents. Other tips: * Look away from the screen for five or 10 seconds every 10 minutes or so. * VDTs with darker letters on lighter backgrounds are easier to read. The screen generally should be as bright as the room. * High-resolution VDTs reduce eye strain. * Darken the room by turning off some lights or covering windows. Move workstations so windows are at right angles to the VDTs, not directly in front or behind them. Block window light with a room partition. * Ask your eye doctor whether you would benefit from a prescription tailored for your work at VDTs, especially if you wear bifocals.