Refractive surgery is common method to correct refractive errors. Volunteers for this surgery are on the rise. Today refractive surgery is a very common method to correct refractive errors. Also there are many volunteers for this kind of surgery. Kratoconus is a uninflamatory progressive condition which leads to attenuation of the cornea as well as protrusion and ectasia. Therefore the early detection of kratoconus is a highly challenging topic among ophthalmologist who is performing refractive surgery. In this study biomechanics information from different instrument such as corves،pentacam & Casia was evaluated for consistence and agreement in early detection of keretoconus or those who are suspects.

from more than thousand participants who were candidate for refractive surgery, two hundred eyes from 109 participants (aged 30.3±5.7years) (30.5% Male and 69.5% Female) met inclusion criteria during 20016-20018. These subjects had at least one factor from pentacam which is indicated KCN suspect. Full eye examination was performed. Information from pentacam topographer, anterior segment OCT (casia), and Corvis device were included.

The mean of CBI and TBI were 0.1±0.2 and 0.44±0.39 respectively. According to finding from this study the most sensitive factors between two devices (pentacam and corvis) were TBI and IS value in KCN suspect patients. Also the CBI and BAD were highly specific factors between two devices mentioned above. In addition, Minimum thickness and CBI had specifity of 97.7 in detection of healthy cornea. Furthermore, TBI is more sensitive factor in compared with CBI in KCN suspect. Finally, the mean values for Ectasia screen was above zero, although TBI and CBI were in normal ranges.

There is not much agreement between devices for KCN suspect detection. However, there was significant agreement only between BAD and TBI. Therefore they can be used interchangeably.