Comparison of Wide-Field Fluorescein Angiography and 9-Field Montage Angiography in Uveitis

Abstract

Purpose To qualitatively and quantitatively compare Optos© fundus camera fluorescein angiographic images of retinal vascular leakage with 9-field montage Topcon© fluorescein angiography (FA) images in patients with uveitis. We hypothesized that Optos images reveal more leakage in uveitis patients. Design Retrospective, observational case series. Methods Images of all uveitis patients imaged with same-sitting Optos FA and 9-field montage FA during a 9 month period at a single institution (52 eyes of 31 patients) were graded for the total area of retinal vascular leakage. The main outcome measure was area of fluorescein leakage. Results The area of apparent FA leakage was greater in Optos images than in 9-field montage images (median 22.5 mm2 vs. 4.8 mm2, P<0.0001). Twenty-two of 49 (45%) eyes with gradable photos had at least 25% more leakage on the Optos image than on the montage image. Two (4.1%) had at least 25% less leakage on Optos, and 25 (51%) were similar between the two modalities. Two eyes had no apparent retinal vascular leakage on 9-field montage but were found to have apparent leakage on Optos images. Twenty-three of the 49 eyes had posterior pole leakage, and of these 17 (73.9%) showed more posterior pole leakage on the Optos image. A single 200 degree Optos FA image captured a mean 1.50x the area captured by montage photography. Conclusion More retinal vascular pathology, both in the periphery and the posterior pole, is seen with Optos FA in uveitis patients when compared with 9-field montage. The clinical implications of Optos FA findings have yet to be determined.

Measuring the precise area of peripheral retinal non-perfusion using ultra-widefield imaging and its correlation with the ischaemic index

“…This would typically lead to overestimation of the size of a peripheral lesion, since ophthalmologists often refer to reference structures in the posterior pole to estimate size of other objects in the fundus. For example, previous studies have described conversion rates for areas measured in pixels by assessing the number of pixels in central landmarks such as the optic disc21 or the retinal vein diameter at the margin of the disc,14 and deriving a conversion rate for pixels 2 to mm 2 . These methods, however, do not account for peripheral warp of UWF images.…”

“…UWF imaging technology has been applied to colour fundus photography,3 fluorescein angiography (FA),4–6 fundus autofluorescence,7 8 and, more recently, indocyanine green angiography 9. UWF imaging has been shown to be of relevance in many common retinal diseases, including diabetic retinopathy,5 10–12 age-related macular degeneration,7 retinal vein occlusion (RVO),6 13 uveitis14 and retinal dystrophies 15 16…”

“…There is significant non-linear warp at the periphery of UWF images,14 16 17 and, to date, there is no accurate way to determine the precise area of non-perfusion. Instead, previous investigators have quantified the severity or extent of non-perfusion by expressing the number of pixels within an area of non-perfusion as a percentage of the number of pixels seen within the total visible retina (an ‘ischaemic index’) 4 5 18…”

Ultra-Widefield Retina Imaging: Principles of Technology and Clinical Applications

“…Similar to DR, UWF imaging enabled clear visualization of the areas of neovascularization and peripheral nonperfusion, which requires sector photocoagulation, hence minimizing complications. Compared to 9-field standard FA, UWF FA found significantly more leakage even in areas captured well with standard angiography such as the posterior pole in uveitis [51]. In addition, UWF FAF is useful in determining whether lesions are in a state of active inflammation in patients with uveitis.…”

The Role of Ultra-widefield Retinal Imaging as a Standard Assessment Tool in the Cataract Practice

“…[4][5][6] A review of data from more than 3 years of research with UWF imaging confirmed that that 66% of clinically relevant retinal pathology is found outside the reach of conventional fundus photography. 7 In our perioperative assessments, the functional capabilities of Optos systems make UWF imaging a useful adjunct to OCT and other standard examination tools, particularly in providing an efficient way to examine the retinal periphery.…”