Purpose
Although peripheral retinal evaluation with ultra wide-field (UWF) fundus photography and fluorescein angiography (FA) is becoming increasingly important in the diagnosis, monitoring and treatment of numerous retinal disorders, a direct assessment of the area of the retina imaged among various wide-field devices is lacking. The purpose of this study is to determine the extent of the peripheral retina visualized on UWF-FA using the Optos® P200Tx and Heidelberg Spectralis® non-contact wide-field lens.
Methods
Primary gaze, single-shot images of 10 eyes of 5 patients who underwent UWF-FA with both the Optos® P200Tx and Heidelberg Spectralis® non-contact wide-field lens were superimposed, taking into account differences in magnification and peripheral retinal distortion seen on the Optos®. The area of imaged retina was outlined and quantified using Adobe® Photoshop® software. The superior, inferior, nasal and temporal retina visualized was determined and compared between the two devices.
Results
The Optos® 200Tx captured a total retinal area averaging 146,562 pixels, ranging from 116,998 to 205,833 pixels due to lid and lash artifact; the total area of the retina visualized with Heidelberg Spectralis® was 101,786 pixels, ranging from 73,424 to 116,319 pixels. The average area of individual quadrants imaged by Optos® compared to Heidelberg® was: Superior (32,373 vs. 32,789), Inferior (24,665 vs. 26,117), Temporal (47,948 vs. 20,645), and Nasal (46,374 vs. 22,234).
Conclusions
UWF-FA with both the Optos® and Spectralis® system are excellent imaging devices which allow for visualization of peripheral retinal pathology beyond that which could be seen on the traditional ETDRS 7-standard fields. On a single shot primary-gaze image, the Optos® visualizes a larger total retinal surface area compared to the Heidelberg®. Optos® captures a wider view temporally and nasally; however, the effect of the eyelids and lashes considerably limits high-quality view to the far superior and inferior periphery with the Optos®. The Heidelberg® non-contact wide-field lens was able to image peripheral pathology located superiorly and inferiorly which may be missed with an Optos® UWF-FA. The ability for eye steering to visualize even more of the peripheral retina was not evaluated in this study.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
550 imaging/image analysis: clinical