The eye with its complex optical system receives the light, refracts (bends) the rays and converts them into images. The refractive power of the eye's optical system, or refraction, is measured in diopters (D).

Light first passes through the cornea, the clear front “window” of the eye and optically the most powerful layer of the eye. The cornea’s refractive power bends (refracts) the light rays that move freely through the pupil, the opening in the center of the iris that regulates the amount of rays entering into the eye. After passing through the iris, the light rays pass through the eye’s natural crystalline lens, the clear, flexible structure that works like the lens in a camera, shortening and lengthening its width in order to focus light rays properly. Through a dense, transparent gel-like substance, called the vitreous body light rays reach a sharp focusing point on the retina. The retina functions much like the film in a camera. It is responsible for capturing all the light rays, processing them into light impulses, then sending them to the brain via the optic nerve.

Similarities between eye’s optic system and photographic camera

Depending on where the rerfracted light rays are focused in the optical system of the eye (on the retina, in front of it or behind it), the clinical refarction can be classified as Emmetropia or Ametropia.

Emmetropia is considered as a normal refraction of the eye when the refractive power of the optic system corresponds to the axial length of the eye and the light rays focus perfectly on the retina. In condition when the above-mentioned correspondence is altered, two different types of the ametropia develop: nearsightedness (myopia) and farsightedness (hyperopia).

With the Nearsightedness refracted light rays focus in front of the retina that might be due to the stronger than normal refractive power of the cornea and/or higher than normal axial length of the eye.

With the Farsightedness due to the  to the weaker than normal refractive power of the cornea and/or lower than normal axial length of the eye refarcted light rays focus behind the retina, in the virtual space.

Refractive errors of the eye also include Astigmatism. With the astigmatism the low visual acuity is due to the fact that the refracted light rays focus on different points of the retina instead of one point and the image is blurry.

Types of refractive errors

Refractive errors usually manifest by deacrease in visual acuity.

Diagnosis of the refractive errors requires complete ophthalmological examination which includes:

• Patient history: detailed analysis of the patient’s complaints.
• Visual acuity: It is necessary to perform visual acuity test without correction and with best correction.
• Refraction: The refraction should be assessed twice – without cycloplegia and following it. Cycloplegia is achieved with mydriatic drops that paralyze the ciliary muscle of the eye and results in a loss of accommodation. Accommodation paralysis allows us to determine the true refractive error of the eye.
• Keratometry/Ophthalmometry: It is required to determine the refractive power of the cornea.
• Biometry: It is required to assess the axial length of the eye.
• Corneal Computer Topography: Provides a multitude of corneal refractive (keratometric), topometric, tomographic, and pachymetric data.
• Biomicroscopic evaluation: Examination of the anterior and posterior segment of the eye with the slit lamp.

Following options are available for the correction of the refractive errors:

Eyeglasses: The simplest way to correct refractive errors.

Contact Lenses: May provide clearer vision, a wider field of vision and greater comfort compared to the eyeglasses. Individuals who wear contact lenses though have a higher risk for developing an eye infection if they don’t follow the usage guidelines properly.  

Refractive Surgery: In cases when the patient isn’t willing or isn’t able to wear eyeglasses and/or contact lenses, refractive surgery is used with big success rates. Refractive surgery means Laser Vision Correction and/or Phakic “Magic” Intraocular Lens implantation for the correction of the refractive errors.

By the LASIK Vision Correction the cornea is reshaped by the excimer laser beam and in a few seconds the correction of the refractive errors is achieved. Due to the ease, safety and the efficacy of the procedure, LASIK is considered as the most popular method of the Laser Vision Correction. 

In the clinic „Akhali Mzera“ we use Excimer Laser “Technolas Teneo 317 Model 2“, the the latest evolution of the excimer laser technology by the world leading ophthalmic healthcare brand “Bausch + Lomb”. With the fastest treatment time of the device we can treat refractive errors in just a few seconds. A leading multidimensional high-speed eye tracker technology in the ophthalmic industry allows us to carry out the procedure with maximum precision and safety. The ergonomic design of the device ensures that the procedure is carried out in comfortable conditions for both the patient and the surgeon. All the above-mentioned ensures high efficiency and safety of the excimer laser refractive surgery.

Akhali Mzera’s team of experienced experts makes a decision whether each specific patient is a good candidate for the Laser Vision Correction based on a thorough ophthalmological examination.

In cases when the Laser Vision Correction is less effective and/or contraindicated, Phakic Intraocular Lens (ICL) implantation is considered as a successful method for the corretion of the refractive errors. The indications for the ICL implantation mainly include high myopia, hyperopia and astigmatism. Within just a few hours after the ICL implantation the maximum possible visual acuity is achieved, that’s why the patients have called it the „magic lens“. The decision about the type of the most suitable refractive surgery method is based on the data of the thorough ophthalmic examination – if there is any contraindication and/or the slightest risk for the develoment of any complications following the Laser Vision Correction, the phakic intraocular lens implantation is considered in order to offer the patient the safest correction method in each particular case.

In cases of very high refractive errors, when vision correction can’t be achieved by one method, the so-called Bioptics is used, which involves a combination of two different methods to achieve maximum possible results.

Refractive surgery is performed by Professor Merab Dvali who first implemented the methods in the whole South Caucasian region with 25 years of experience.

Theefore, if your visual acuity is decreased due to the refractiver errors, our clinic offers cutting-edge technologies for the diagnosis and correction of them. Following the complete ophthalmic examination you can make a decison together with your doctor and/or surgeon about which refractive surgery type is most suitable for you.