We refer to the article "Blue light filtering glasses: Just how effective are they?" (March 16).

The use of computer and electronic devices is common and up to two-thirds of users report eye strain or "computer vision syndrome", with symptoms including blurring of vision, dry eyes, eye redness and headache.

Computer vision syndrome is estimated to affect 60 million people worldwide, and there is substantial interest to provide remedies for this complaint.

It has been hypothesised that blue light from the computer screen may cause eye strain and blue light filtering glasses have been marketed, claiming to reduce eye strain from screen usage.

In 2017, the Ophthalmic And Physiological Optics journal published a review of the literature on the effect of blue-light blocking spectacle lenses on visual performance and the sleep cycle.

It found a lack of high-quality evidence to support the use of blue-light blocking spectacles to improve visual performance or sleep quality, or to alleviate eye fatigue.

Last month, the American Journal Of Ophthalmology published the results of a double-masked, randomised controlled trial addressing the question "Do blue-blocking lenses reduce eye strain from extended screen time?".

The results showed that in the 120 participants, blue-light filtering spectacles were not found to alleviate symptoms or signs of eye strain associated with computer usage.

Hence, the conclusion was that it was extremely unlikely that blue light was a contributory factor to eye strain associated with computer use.

It is also unclear whether blue light emitted from electronic devices may cause eye strain.

It should be noted that electronic devices emit far less blue light than natural light, and the blue light from electronic devices is well within the safety standards for the eye.

The cause of computer vision syndrome may be multi-factorial, and a comprehensive eye examination and a review of computer workstation ergonomics is advisable.

More data or larger randomised studies will be required to determine the true effectiveness of blue light filtering glasses.

We advise the public to discuss the available evidence with their eyecare professionals before making informed choices.

Lim Li (Dr)

Chairman, Cornea Subspecialty Committee

Vernon Yong (Dr)

President

College of Ophthalmologists

Academy of Medicine, Singapore