Can myopia be treated by applying pressure?

Question

I have high myopia in my right eye (~7.00). I've noticed that unsystematically applying pressure onto certain areas of the eyelid onto the eye can actually bring the power down to about 3-5.00 (by comparing it with my left eye), enough to read. It makes the vision a bit darker though (probably because the eyelid partially covers it), and can shift it a bit.

Since myopia is basically the elongation of the eyeball, this shouldn't be a surprise. But I'm wondering, surely applying specific continuous pressure (perhaps via some eye cover mould contraption during sleep) has been thought of as a possible treatment option? Has it been dismissed due to some obvious reason?

Applying pressure over time can definitely deform the body, at least in some areas. Fitbit and watch users have complained about noticeable indentations left by their watches, which don't seem to go away even after not wearing them. Even spectacles can leave indentation marks. Is the eyeball any different?

Update: As jf1 answered, orthokeratologic contact lenses already exist, which can reshape the cornea to slow the progression of myopia. Just to probe further for completeness, have methods for reversing the physical elongation of the eyeball (not just the cornea) via pressure been studied before?

Answer 1

Actually this is done, despite a little bit different:

So called orthokeratologic (ortho-K, OK) contact lenses are worn over night and during this time reshape the cornea. Its main focus however is slowing myopia progression in children. It does not help reverse myopia, once aquired. And one has to wear them every night.

See e.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5721542/ or https://www.ncbi.nlm.nih.gov/pubmed/26310255

Answer 2

See Eyeball squeezing could correct sight reported on 21 March 2002 by Paul Marks and Catherine Zandonella?

A light tap on the side of your head could one day restore your eyesight, believe scientists. The tap would tighten a band of artificial muscle wrapped round your eyeballs, changing their shape and bringing blurry images into focus. While the idea has a high ‘yuk’ factor, the people behind it are confident it will be a safe and effective way to improve vision.

![(https://images.newscientist.com/wp-content/uploads/2002/03/dn2064-1_800.jpg?width=800)

How artificial muscles put the squeeze on poor sight

Mohsen Shahinpoor and his team at the University of New Mexico call their artificial muscle a “smart eye band”. It will be stitched to the sclera, the tough white outer part of the eyeball, and activated by an electromagnet in a hearing-aid-sized unit fitted behind one ear.

Most of the eye’s focusing is done by the cornea, the hard transparent surface that covers both the pupil and the iris; the lens is responsible only for fine-tuning. Light travels through the cornea and lens to focus on the retina at the back of the eyeball. The closer an object is, the farther back in the eye it will be focused. The lens compensates by adjusting its strength to bring the focus back onto the retina.

If the cornea or lens do not focus strongly enough or the eyeball is too short, the light will focus behind the retina, blurring images of close-up objects. This is long-sightedness. Conversely, if the eyeball is too long, the light will focus in front of the retina, yielding the blurry images of far-off objects characteristic of short-sightedness.

Elongated eyeball

Tightening the smart eye band causes the eyeball to elongate, just as squeezing the middle of a peeled hard-boiled egg causes the egg to lengthen. In long-sighted people this pushes the retina backwards, bringing close-up objects back into focus.

Expanding the eye band causes the eyeball to shorten. In short-sighted people this will bring the retina forward to intersect with the focused light, making far-off images sharp and clear again.

Stitching a band of artificial muscle to your eyeball sounds drastic, but Shahinpoor says the necessary surgical techniques are already commonly used for treating detached retinas. He claims his smart eye band is far more flexible than laser surgery, in which a laser flattens the cornea by eroding part of it. Laser surgery can only correct short-sightedness.

Click and read

With the smart eye band implanted, you’d set your eyes to read a book, say, by clicking a button on the device sitting behind your ear. This would generate a magnetic field to activate the eye band’s artificial muscle.

The artificial muscle comprises a series of “bi-strips” (see graphic), each made up of two lengths of a biocompatible polymer containing lithium ions, surrounded by a coil of thin gold wire. At the end of each bi-strip is an electrode.

Switching on the magnetic field induces a pulse of current in the coil, which in turn builds up a small charge on the electrodes. The positively charged lithium ions in the polymer are attracted to the negative electrode, causing the whole bi-strip to bunch up and tighten the band around the eyeball. So the eye’s focal length becomes electronically controllable.

Though Shahinpoor’s idea is still on the drawing board, Jim Schwiegerling of the Optical Sciences Center at the University of Arizona says the technology could be of enormous benefit to older people who have lost the ability to change focus from distant to near objects.

“When you sit down to read a book, you could just switch it on, and when you are done reading, you could turn it off and go out and drive a car,” he says. Shahinpoor will present the design for his bionic eye at an optical technology conference in San Diego, California later in March.