Patients with unilateral retinal vein occlusion show reduced radial peripapillary capillary density in their fellow eyes

Background To evaluate the radial peripapillary capillary (RPC) density in the fellow eyes of unilateral retinal vein occlusion (RVO) patients using optical coherence tomography angiography (OCTA), and further analyze the correlation between RPC density and peripapillary retinal nerve fiber layer (RNFL) thickness. Methods Seventy-eight unilateral RVO patients and 70 normal controls were included in the study. OCTA was conducted with the 4.5 × 4.5-mm scan pattern centered on the optic nerve head, and the RPC density and peripapillary RNFL thickness were quantified. Results The peripapillary RNFL in the RVO fellow eyes was significantly thinner than in normal controls in the average, inferior-hemisphere, inferior quadrant, and temporal quadrant (P < 0.05, respectively). The RPC density in the fellow eyes was also significantly lower in the average, inferior-hemisphere, nasal quadrant, and temporal quadrant ((P < 0.05, respectively). There were no significant differences in RNFL thickness and RPC density between branch RVO fellow eyes and central RVO fellow eyes. Pearson’s correlation analysis showed significant positive correlations between the RPC density and RNFL thickness in all measurements (P < 0.001, respectively). Conclusions The regional RPC density was reduced in the RVO fellow eyes, which might contribute to peripapillary RNFL thinning in the corresponding region, suggesting the influence of systemic risk factors on RVO. OCTA may offer new insights into the pathophysiology of RVO.

OCT-A evaluation of radiation vasculopathy following slotted plaque brachytherapy

Purpose: To determine a reliable diagnostic method to reveal and monitor subclinical progression of neural and perineural radiation vasculopathy. Methods: A retrospective cross-sectional study, where optical coherence tomography angiography (OCT-A) imaging data was collected and analyzed from 22 consecutive patients that had been treated with circumneural slotted plaque brachytherapy for peripapillary, juxtapapillary, or circumpapillary choroidal melanomas. Pre-operative dosimetry of palladium-103 radiation dose to the optic nerve and fovea were collected. Quantified differences in OCT-A-measured vessel density and length in treated verses untreated contralateral control eyes were collected. Vessel density and length were correlated to radiation dose, plaque slot depth, visual acuity outcomes, and circumpapillary retinal nerve fiber layer thickness. Results: Patients had post-irradiation follow-up of median 39 months, interquartile range 62 months). The mean optic disc radiation dose was 89.9 Gy ± 39.2 (86.5, 30.8–189.0). In comparison to controls, OCT-A imaging revealed significant differences in radial peripapillary capillary vessel density (18 μm2 in case eyes, 34 μm2 in control eyes; p < 0.001) and length (10 μm in case eyes, 14 μm in control eyes; p < 0.001). Change in vessel density did not show a significant correlation to radiation dose, slot depth, or visual acuity. However, change in vessel length was significantly correlated to radiation dose ( p = 0.049) and change in visual acuity ( p < 0.001). Conclusions: OCT-A imaging revealed that radial peripapillary capillary vessel density and length were significantly reduced after circumneural irradiation for choroidal melanoma. Therefore, OCT-A imaging can be used to monitor progression of papillary vasculopathy associated with radiation optic neuropathy.

Changes in parafoveal and peripapillary perfusion after decompression surgery in chiasmal compression due to pituitary tumors

We evaluated changes in parafoveal and peripapillary vessel density in chiasmal compression after decompression surgery using optical coherence tomography angiography (OCT-A). Sixty-two eyes with chiasmal compression for which preoperative and postoperative (4–6 months) OCT, OCT-A, visual field (VF), and comprehensive ophthalmic data were available, and 44 healthy eyes were evaluated. Vessel densities of the superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment were assessed using OCT-A. The postoperative measurements were compared with preoperative data. Preoperative peripapillary retinal nerve fiber layer, macular ganglion cell-inner plexiform layer thickness, and vessel densities of SRCP and RPC segments in patients’ eyes were significantly reduced compared to those of healthy controls (P < 0.0001, P < 0.0001, P = 0.0052, and P = 0.0085, respectively). Vessel densities were significantly decreased in the SRCP (P < 0.0001), DRCP (P = 0.0017), and RPC segments (P < 0.0001) after surgery compared to the preoperative values. Significant associations between the postoperative SRCP and DRCP vessel density changes and preoperative SRCP (r = − 0.3195, P = 0.0114) and DRCP (r = − 0.5165, P < 0.0001) vessel densities were found, respectively. There were also significant associations between postoperative SRCP vessel density changes and VF changes (r = − 0.2586, P = 0.0424). These findings indicate that decreased perfusion around the optic nerve head and on the macula associated with chiasmal compression could further progress after decompression surgery. Further functional and longer-term clinical studies are needed to elucidate the clinical implications of these findings.

Structural and microvascular changes of the peripapillary retinal nerve fiber layer in Von Hippel–Lindau disease: an OCT and OCT angiography study

Von Hippel–Lindau (VHL) disease is an autosomal dominant genetic disease caused by VHL gene mutation. Retinal hemangioblastomas (RH) are vascularized tumors and represent the main ocular manifestation of the disease. Histopathologically, RH are composed of capillary vessels and stromal cells, the neoplastic population of the lesion. The origin of these stromal cells remains controversial, even if they are hypothesized to be glial cells. The aim of the present study was to investigate neuronal and microvascular changes of the peripapillary retinal nerve fiber layer, in which glial cells, neurons and capillaries (the radial peripapillary capillary plexus) interact. VHL patients with or without peripheral RH were enrolled and compared to healthy controls. Mean peripapillary retinal nerve fiber layer (pRNFL) thickness was measured by means of optical coherence tomography (OCT). The following vascular parameters of the radial peripapillary capillary plexus were quantified using OCT angiography: Vessel Area Density,Vessel Length Fraction, Vessel Diameter Index and Fractal Dimension. One hundred and nine eyes of 61 patients, and 56 eyes of 28 controls were consecutively studied. Mean pRNFL was significantly thinner in VHL eyes without RH versus eyes with RH and controls. Mean pRNFL thickness did not differ between VHL eyes with RH and controls. All OCTA vascular parameters were reduced in VHL eyes with or without RH versus controls, with significative difference for Vessel Diameter Index. The same OCTA parameters did not significantly differ between VHL eyes with or without RH. In VHL eyes without RH, pRNFL thinning may be the consequence of impaired perfusion of the radial peripapillary capillary plexus, while the increase of pRNFL thickness in VHL eyes with RH may depend on possible activation and proliferation of the other RNFL resident cells, the glial cells.