Comparison of Wide-field Retinal Imaging

Fundus imaging has become an integral tool in retinal diagnosis. Although single-field fundus photography covers a vital region of the retina, it leaves a large portion of the periphery undiscovered. Ultra-wide-field imaging systems allowed for visualization of peripheral perfusion abnormalities in myopic eyes that were previously unknown. In Austria, there are two different wide-field imaging systems available. The first device on the market was the Optos (Optos PLC, Dunfermline, UK) and several years later the Clarus 500 (Carl Zeiss, Meditec AG, Jena, Germany) was introduced.

While both of the studied imaging systems have the possibility of a 200° view of the retina, we would asses if the differences between the two devices affect the extent of retinal periphery view and if ocular ametropies which come with different retinal pathologies would affect the retinal periphery assessment. Aim: To compare two CE-marked imaging systems concerning the extent of retinal periphery area viewing. We would like to perform a prospective observational study that would include patients divided into three groups: myopic patients, hyperopic and emmetropic patients. Fundus photography will be performed using two ultra-wide-field imaging systems (Optos, Daytona, Optos PLC, Dunfermline, UK and Clarus, 500 Carl Zeiss, Meditec AG, Jena, Germany), performed by the same investigator. All images with sufficient quality will be exported and saved to hard-disk. The difference in periphery view will be investigated as follows: two retinal photos for each patient will be imported into Photoshop CS6 image-editing system (Adobe, version 13.0.0) where the anatomical landmarks will be matched for each image and the borders will be compared to see if there are differences in retinal periphery area viewing between the two devices.

Extent of retinal periphery area viewing (the difference in periphery area between the two devices). Images of the same patients will be compared to determine the degree of periphery viewing for the two devices.

Inclusion Criteria: Patient over 21 years old Myopic (at least -5.00Dsph), hyperopic (over +3.00Dsph) and emmetropic patients Written informed consent prior to any study specific action. Exclusion Criteria: Extensive cataract or severe corneal scaring that would affect image quality Fixation problems, nystagmus pregnancy- for women in reproductive age a pregnancy test will be performed.