The Statement
A Facebook post and video by a company advertising “pinhole” glasses claims that their product can permanently correct poor vision.
The post’s text says that wearing pinhole glasses for 15-20 minutes a day can “encourage the ciliary muscles to become stronger by pulling the lens into the correct shape, so the eyes regain their ability to focus properly”.
It adds that the glasses “can be worn on a daily basis, when reading, watching TV” and “many users have found their sight has been improved”.
The page has made similar claims in other posts about pinhole glasses – see here, here and here. According to Facebook’s transparency tools, the page is managed by accounts based in Romania and the Philippines, while the post has been shared in New Zealand among other countries. At the time of writing, the video had been viewed more than 82,000 times.
The Analysis
While pinhole glasses do have their uses, experts say they do not correct vision permanently – and they can even be unsafe to wear long-term.
Pinhole glasses are glasses with small holes poked through their lenses. They reduce the amount of light the eye lets in, and are often used for diagnostic purposes by eye doctors.
Himal Kandel is an optometrist who works with the University of Sydney’s Save Sight Institute. Among his publications are several focusing on refractive errors in the eye, which cause blurred vision.
In an email to AAP FactCheck, Dr Kandel explained how pinhole glasses work: “Pinhole glasses are used clinically to detect if the vision loss is due to refraction problems (i.e. to find out if glasses can improve vision or not). They just cut off the peripheral rays of light and reduce blur circle in the retina – they don’t change anything in the lens or ciliary muscle.”
Helen Danesh-Meyer, the first female professor of ophthalmology in New Zealand and head of Academic Neuro-ophthalmology and Glaucoma Research Unit at the New Zealand National Eye Centre, told AAP FactCheck in an email that “pinhole glasses do not correct vision permanently”.
“They will only work for the time you are using them because in a way they ‘overcome’ the refractive error of the eye. However, they also decrease your peripheral vision because of the small aperture,” she said.
Dr Kandel agreed and said the glasses were not recommended for daily use, adding: “In fact, they can be unsafe to wear as they limit a significant amount of light entering the eye and can even lead to accidents if worn in dim light conditions.”
Pinhole glasses reduce the field of what’s known as the “blur circle” on the retina. This gives the wearer’s vision extra clarity – but again, only when they have the glasses on.
Academic studies on pinhole glasses also provide no support to the suggestion that they can correct vision permanently.
A 2017 Korean study found that multiple and single pinhole glasses “caused significant ocular discomfort after reading compared with baseline and symptoms were worst with MPH (multiple pinhole glasses).” It did note that visual acuity improved while both types of glasses were worn due to the “pinhole effect” reducing peripheral vision.
A 2018 Malaysian study also found pinhole glasses “did not improve the refractive error of myopic participants”.
A 1993 study that compared pinhole glasses to refractive spectacles found that “pinhole glasses cause a constriction of the peripheral field as well as a generalised depression or dimming of the entire visual field”, adding that this meant use of the glasses at night or while driving could be hazardous.
Dr Kandel said claims that pinhole glasses could change vision permanently were misleading, and they were often based on misunderstanding the effect the glasses had while they were being worn.
“Patients are often astonished when they can see the bottom letters in the visual acuity charts when seeing through the pinhole glasses, and therefore are vulnerable when they see such promotional materials,” he said.
The Verdict
While pinhole glasses are useful for diagnostic examinations, they cannot improve vision permanently. Experts say the glasses are not designed to be worn on a regular basis and may even be unsafe in certain circumstances.
False – Content that has no basis in fact.
Updated Monday, September 20, 2021 9:30 AEDT: Clarified professional specialisation for Himal Kandel.
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