OCT angiography OCTA is a novel imaging platform

OCT angiography (OCTA) is a novel imaging platform that utilizes motion kras-pdeδ inhibitor to visualize macular microvascular perfusion in a rapid, non-invasive, and depth-resolved fashion. Co-registration of structural en face projections of corresponding retinal layers is also performed with micrometer scale depth resolution. This offers the potential to perform quantitative assessment. New OCTA findings have been reported in a variety of fundus abnormalities. The purpose of this report was to characterize and quantify the pre- and postoperative foveal structural and functional patterns in eyes with a full-thickness macular hole.

Methods

Results
Five eyes from 5 patients presenting with a full-thickness macular hole were included in the study. The hole was closed in all eyes after the initial surgery as demonstrated by structural volumetric scans (Fig. 2). En face structural imaging demonstrated hyporeflective areas corresponding to the hole and surrounding cystic areas that were best visualized on the deep retinal slab obtained just below the inner plexiform layer. Co-registered OCTA images showed enlargement of the FAZ and flow void in the areas with cystic changes. These cystic areas could clearly be delineated due to lack of the background noise that was otherwise present in the non-flow areas of the OCTA images (Fig. 3). Postoperative imaging was performed at a mean of 70 (range 56–91) days following surgery. Comparing pre- and postoperative images showed resolution of the cystic structures along with a decrease in superficial and deep FAZ size demonstrating preserved macular blood kras-pdeδ inhibitor flow (Fig. 4).
The baseline, clinical, and imaging characteristics of the patients are presented in Fig. 5. OCTA images of the superficial vascular network showed enlargement of the FAZ and delineation of the holes within the FAZ. Mean preoperative FAZ area was 0.41 ± 0.104 mm2. Visual acuity was improved and FAZ area was reduced to 0.27 ± 0.098 mm2 postoperatively in all cases (P < 0.05) with resolution of the macular hole and adjacent cystic areas. En face images of the middle retina showed the preoperative cystic areas surrounding the hole in all cases. These appeared as different patterns ranging from larger, regular, and well-defined radial cystic areas with a petaloid or “grapefruit” configuration (Patient 1) to smaller, more dispersed cystic areas with a “sponge-like” appearance (Patient 5). The cross-sectional areas of the macular hole, cumulative area of the cystic spaces, and number of cystic areas appearing on the deep retinal slab were calculated using the automated algorithm previously described. Fig. 5 demonstrates increasing hole area from patient 1 through 5. As such, smaller holes showed fewer but larger cystic areas and larger holes had more numerous but smaller cystic areas.

Discussion
Evolving technologies such as en face OCT and adaptive optics have helped expand our understanding of the foveal ultrastructural changes that occur during macular hole formation and following surgery, as well as the impact of these changes on functional vision. With its improved acquisition speed and sensitivity, SD-OCT allows for three-dimensional (3D) imaging of the macular area. This form of volumetric imaging is clinically useful both for the physician and also for patient education. Previous studies on 3D imaging have demonstrated the ability to visualize intraretinal microstructures in consecutive orthogonal cross-sectional and sectioned volume images. This enables for much more precise and minute observations of structural changes associated with macular holes than conventional OCT imaging. Furthermore, the volumetric data obtained allows for comprehensive measurement of retinal layer thickness. Novel image processing algorithms such as SSADA also enable simultaneous characterization of blood flow using OCTA.