Myopia, or nearsightedness

Myopia, commonly known as nearsightedness or short-sightedness, is an optical refractive error where close objects appear sharp and clear, but distant objects appear blurred and out of focus.

According to the World Health Organization, myopia has become one of the fastest-growing visual disorders worldwide. It is projected that by the year 2050, nearly 50% of the global population — approximately 5 billion people — will be myopic.

The optics and the anatomy

In an eye with normal vision, emmetropia, light rays enter through the cornea and natural lens, refracting precisely onto a single focus point on the retina at the back of the eye.

In a myopic eye, light rays focus in front of the retina instead of directly on it. By the time the light reaches the retinal surface, the rays have diverged, creating a blurred image.

There are two anatomical causes:

• Axial elongation, the most commonThe eyeball grows excessively long from front to back. The average adult eye measures 23–24 mm. Every additional millimetre of axial length adds approximately −3.00 dioptres of myopia.
• Refractive myopiaThe cornea or crystalline lens has excessive refractive curvature, bending light too sharply.

Clinical symptoms

• Blurry distance vision: difficulty reading street signs, classroom whiteboards or cinema screens.
• Persistent squinting, which narrows the eye opening and briefly improves focus.
• Frontal tension headaches and eye strain from prolonged accommodation.
• Night myopia: difficulty seeing clearly while driving in low light.

Reading your prescription

Myopia is indicated on an optical prescription by the term SPH, sphere, with a minus sign.

• Mild myopia: up to −3.00 DDistant objects are slightly blurred, but everyday tasks are often manageable.
• Moderate myopia: −3.25 to −6.00 DDistance vision is clearly affected and managing without correction is difficult.
• High myopia: above −6.00 DVision is already unclear a few tens of centimetres away.
• Pathological myopia: above −8.00 to −10.00 DAccompanied by severe degenerative structural changes in the eye.

Myopia in children, and why it is rising

Myopia typically develops during school age, between eight and twelve, during rapid body growth.

Signs a child may be short-sighted:

• The child sits unusually close to the television or a screen.
• Tilts their head while reading, or holds a book right under their nose.
• Says they cannot read what is written on the board at school.
• Rubs their eyes often, or has headaches in the evening.

Children's vision can be checked from the age of two and a half — see children's eye examination.

The risks of high myopia

High myopia stretches the internal ocular tissues — the retina, the choroid and the sclera — sharply increasing the lifetime risk of serious sight-threatening disease.

• Retinal tears and detachmentA stretched retina in an elongated eye can tear. The risk is up to 39 times higher in high myopia.
• Open-angle glaucomaThe risk of optic nerve damage from raised intraocular pressure increases by roughly 20% per dioptre.
• Myopic macular degenerationDegeneration and scarring of the central retina.
• Premature cataractEarly clouding of the natural lens.

How myopia is diagnosed

Reading a letter chart is not enough. A comprehensive evaluation includes:

• Objective refractionAccurate measurement of the refractive power of the eye.
• Optical axial biometryHigh-precision measurement of the length of the eyeball, to a hundredth of a millimetre.
• 3D corneal topographySurface mapping across thousands of points, to rule out corneal disease such as keratoconus.
• Dilated ophthalmoscopyExamination of the peripheral retina for tears and thinning.

Ways of correcting myopia

A permanent solution at KSA: touch-free, blade-free Flow3

When glasses and contact lenses tire you or limit an active life, one answer is laser vision correction. At KSA Vision Clinic myopia is corrected with the Flow3 procedure. Flow3 is for people aged 18 to 45 whose myopia has been confirmed at a suitability examination.

• Touch-free and blade-freeUnlike older-generation LASIK methods, Flow3 cuts no corneal flap and uses no mechanical blades. The laser works without contact, directly on the surface layer of the cornea.
• Preserved structural integrityBecause no incisions are made into the cornea, the biomechanical strength of the eye is retained.
• Fast, comfortable recoveryThe procedure itself takes only a few minutes. Sport, training and swimming are possible 7 days afterwards, once the bandage lenses have been removed.
• Long guarantee and safetyKSA Vision Clinic has been operating since 2005 and has carried out more than 300,000 eye examinations. Thanks to a strict pre-screening protocol there has not been a single case of corneal weakening, ectasia, in that time. Depending on the package, the procedure carries a guarantee of up to 10 years.

The first step: a Vision Audit examination

Clear vision begins with a detailed diagnosis. The Vision Audit is a comprehensive eye examination in Tallinn and Tartu, in which optometrists and ophthalmologists assess corneal thickness, 3D topography and intraocular pressure, and establish whether your eyes are suitable for a laser procedure.

We examine in Tallinn and in Tartu. The laser procedure itself is done in Tallinn, because that is where the laser is.

Closely related: astigmatism, which often occurs together with myopia and is corrected in the same procedure.