Surgical Correction of Myopia

*Maja Bohac, Maja Pauk Gulic, Alma Biscevic and Ivan Gabric*

### **Abstract**

Myopia is the most prevalent refractive error in the world and its incidence is increasing. Together with conservative methods of treatment, various surgical methods have been proposed. Corneal refractive surgery is probably the most accepted one. Laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) are suitable for treatment of myopia up to −8.00 D in the younger age group. For patients not suitable for corneal refractive surgery, lens-based procedures are available. Phakic intraocular lenses are suitable for patients younger than 45 years of age with high myopia or some other contraindications for corneal refractive surgery. For older patients, refractive lens exchange (RLE) with implantation of multifocal or monofocal intraocular lenses is gaining popularity.

**Keywords:** myopia, LASIK, PRK, SMILE, phakic intraocular lenses, refractive lens exchange

#### **1. Introduction**

Myopia is a common refractive error in the population. It is defined as an optical aberration in which parallel light rays from a distant image are getting focused on a point anterior to the retina. Hereditary and environmental factors both play an important role in the development of myopia. Myopia typically appears between the age of 6 and 12, and the mean rate of progression is considered to be approximately 0.50 D per year, based on studies of mostly Caucasian children. One of the studies showed that progression of myopia can vary by ethnicity, as well as by age of the child. For instance, in ethnic Chinese children, the progression rate is higher [1].

A recent report in *Nature*, entitled "The Myopia Boom," demonstrated, and it is now widely accepted, that there is an epidemic of myopia in the developed countries of East and Southeast Asia, paralleled by an epidemic of high myopia [2]. Recent meta-analyses have suggested that close to half of the world's population may be myopic by 2050, with as much as 10% highly myopic [3]. Correction of refractive error can be achieved conservatively with glasses or contact lenses which is the treatment of choice in the childhood. However, despite the long-standing use of glasses and contact lenses, there are some disadvantages in both forms of optical correction. Increased light scatter, image magnification/minification, discomfort, and inconvenience are some of the issues with glasses, while contact lenses may irritate the ocular surface with increased risk of corneal scratches and infections. After the age of 21, various surgical treatments can be considered. The best surgical option depends on the amount of refractive error and the patient's cornea, lens, and age. Available options include various laser vision corrections which are aimed on the cornea, implantation

#### *Intraocular Lens*

of phakic intraocular lenses (pIOLs), and refractive lens exchange (RLE) with implantation of multifocal and monofocal intraocular lenses (IOLs). It is important to perform a detailed examination of each patient and assess their needs, wishes, and expectations. Doctors need to explain in as much detail as possible what the expected results and risk would be with for the selected surgical method.
