Orthokeratology lenses (ortho‑K lenses, night lenses) are rigid gas‑permeable contact lenses that are worn during sleep and removed in the morning.

Ortho‑K lenses gently reshape the curvature of the cornea, improving vision and controlling the progression of myopia. Night lenses rest on the tear film and exert gentle pressure on the corneal epithelium (via hydraulic forces and surface tension). Under the influence of this hydraulic pressure, epithelial cells change their thickness. This change in corneal cells leads to a temporary alteration in the corneal refractive power, correcting refractive errors (myopia, astigmatism, hyperopia).

Studies comparing the safety of conventional contact lenses with overnight orthokeratology lenses (OK lenses) have shown that wearing night lenses does not increase the risk of complications compared to conventional contact lenses.

The most common complications of contact lenses include eye infections, hypoxia, and corneal epitheliopathies – all of which can lead to more serious complications that may even threaten irreversible vision loss.

To avoid complications when wearing contact lenses, always follow your ophthalmologist’s recommendations on lens care, insertion and removal techniques, and replacement schedules.

After removing the night lenses in the morning, high‑quality vision is usually maintained for 24–48 hours.

To achieve optimal results, follow your ophthalmologist’s instructions regarding the regularity of sleeping in the night lenses. Most patients require regular overnight wear of ortho‑K lenses, while some may be allowed to sleep in them every other night.

It has been proven that Ortho‑K reduces the rate of myopia progression in children by 64%¹.

Conventional glasses and contact lenses only provide myopia correction, without affecting the rate of its progression.

Night lenses, by reshaping the cornea, provide good vision during the day and at the same time slow down myopia progression by creating peripheral spherical aberrations in the eye. This optical property is called «induced myopic peripheral defocus» – a defocused beam of light on the periphery stimulates amacrine cells, triggering a cascade of photochemical reactions that strengthen the sclera and slow down excessive eye growth.

Ortho‑K lenses can be prescribed for children, adolescents, and adults.

For myopia treatment, orthokeratology is indicated for children from the age of 7.

OK lenses are also an excellent solution for patients who are not candidates for laser vision correction due to insufficient corneal thickness, high myopia, or severe dry eye.

Night lenses are especially convenient for athletes, as well as for patients who work in dusty or dry environments, or in very hot or cold climates.

Night lenses are fitted in a special way. Ophthalmologists who specialise in myopia control undergo extensive postgraduate training in orthokeratology lens fitting.

The fitting process for ortho‑K lenses involves corneal topography – an assessment of corneal shape – as well as trial lens application. This allows the doctor to design a lens that matches the patient’s eye shape down to the finest detail.

During the initial fitting, the doctor will teach you the insertion and removal technique, as well as the specifics of cleaning and storage.

When starting to wear ortho‑K lenses, patients often note that with their eyes open, the lenses feel like a speck of dust in the eye. It is important to remember that the lenses are intended for overnight wear, and with eyes closed they are completely comfortable! Moreover, even with open eyes, the lenses begin to feel comfortable over time – this is due to changes in corneal sensitivity and adaptation to night lens wear.

Many patients using ortho‑K lenses achieve 100% vision without glasses or contact lenses during the day.

According to the results of a nine‑month FDA clinical study (conducted on standard lenses):

• 95% of patients achieved 0.5 vision or better;

• 73% achieved 1.0 vision or better.

Our clinic uses both standard and fully customised (individual) lenses, which allow us to achieve high visual acuity in an even greater percentage of cases.

The time required to achieve maximum results with orthokeratology lenses depends on the degree of myopia.

For low myopia, high visual acuity can be achieved within one to two days of lens wear.

For high myopia, regular overnight wear for one to two weeks may be required. In such cases, the ophthalmologist may recommend wearing low‑minus glasses during the day until high visual acuity is achieved.

Yes, but you will need to stop wearing the ortho‑K lenses several months before the procedure.

Unlike laser vision correction, night‑lens correction is temporary, and the results last only as long as you continue wearing the lenses.

A few months before your planned vision correction, your ophthalmologist will instruct you to discontinue ortho‑K lens wear. This will allow your cornea to return to its original shape and ensure optimal surgical results.

Orthokeratology lenses are custom‑made, and Astana Vision has its own laboratory for manufacturing all types of lenses.

DAC International (USA) is a recognised global leader in high‑precision CNC lathes for contact lens manufacturing. The use of DAC equipment ensures consistently high quality of the products manufactured by ASTANA VISION.
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