Could watching LCD TVs hinder your eyesight?

Amid the flat-panel TV sales boom, one study suggests that watching liquid crystal display TVs can affect people`s eyesight to a degree that short relief would not be "sufficient" to bring eyes back to their normal status.

Dr. Macoto Takahasi, a human science professor at Osaka University of Education, yesterday revealed the results of his recent study on the correlation between watching flat-screen TVs and visual fatigue and acuity, at the Korea Display Conference 2006 currently held at COEX in Seoul.

The professor stressed the need to evaluate flat-screen TVs from an ergonomic point of view, while comparing LCDs and plasma display panels.

Takahasi`s team conducted an experiment on 20 adults, divided into two groups. One group watched LCD TVs while the other watched PDP TVs for 100 minutes, over four 25-minute sessions.

The TVs used were all manufactured in 2004. The subjects were instructed to watch TV at a distance of 130 centimeters, with an average luminescence level of 100 lux.

According to the report, LCD TVs and PDP TVs did not show meaningful differences in terms of visual fatigue.

PDP TVs however, were rated better in terms of visual acuity, clinically measured by the `grating` method after a 25-minute rest following the 100-minute session.

The average level of vision among LCD TV watchers declined by 0.1 notches after the 100 minutes, the report said.

But in the case of PDP TVs, there was no noticeable reduction of vision among participants, and the average level of eyesight was lowered only by 0.03 notches after the 100 minutes.

"After the 25 minutes` rest, participants in both groups showed recovery in vision, but the recovery was `insufficient` on the part of LCD TV watchers," Takahasi said.

"I assume that it`s mainly because of the `blurring` phenomenon in fast-moving LCD screens."

Also according to the report, PDP TVs received better evaluation than LCD TVs and cathode-ray TVs in terms of picture quality, after summarizing opinions from five expert viewers including TV directors, cameramen and editors.

(siyoungh@heraldm.com)



By Hwang Si-young