Comparison of Different Invasive Types of Refractive Errors Operation

The methods of ammetropia of human eye correction are divided into invasive and non invasive methods. Each method has its own advantages and disadvantages. Each method has limitations due to the type of compensation; therefore it is difficult to make a straight forward decision. In this study we tried to compare the results of methods to find out their predictability, Uncorrected Visual Acuity, safety and stability. We investigated data of 24012 patients of different operation types in published papers by using the following keywords: Conductive Keratoplasty (CK), Hyperopic Thermokeratoplasty (HTK), Diode Laser Thermal Keratoplasty (DTK), Laser Thermal Keratoplasty (LTK), Photorefractive Keratectomy (PRK), Laser In Situ Keratomileusis (LASIK), Laser SubEpithelial Keratomileusis (LASEK). The criteria for selection of papers were safety, predictability, stability and uncorrected visual acuity. Data were analyzed with Chi-square test. For those patients with hypermetropia less than 3.5 diopter, CK and LTK have best correction results, respectively. Then the results of PRK and LASEK were the same. For all range of myopia, LASEK provided the best results and then LASIK was proper for moderate and higher myopia refractive errors, and PRK was useful in low myopia refractive anomalies.