Association of the Pattern of Retinal Capillary Non-Perfusion and Vascular Leakage with Retinal Neovascularization in Proliferative Diabetic Retinopathy

Purpose:

To explore the correlation between retinal capillary non-perfusion and the distribution of retinal neovascularization and vascular leakage (VL) in patients with proliferative diabetic retinopathy (PDR).

Methods:

Ultra-widefield angiograms of 96 eyes of 69 patients with PDR were reviewed for the proportion of non-perfused area to total gradable area, and for the presence of neovascularization and VL.

Results:

Retinal neovascularization was distributed as such: neovascularization elsewhere (NVE), 57.3%; neovascularization of the disc (NVD), 11.5%; both neovascularization of the disc and elsewhere (NVED), 31.3%. The proportion of non-perfused retina, so-called ischemic index, was greater in eyes with NVED compared to eyes with NVE only, but not when compared to NVD only. Overall, 83% of eyes had VL. The presence and the extent of VL correlated with the proportion of the ischemic index. While VL and ischemic index were more severe in the mid-periphery and far-periphery, the majority of NVE was located in the posterior pole.

Conclusions:

The presence of both NVD and NVE is associated with a greater ischemic index than NVE alone. Although both VL and ischemic index is significantly higher in peripheral zones, the majority of neovascularization occurs at the posterior pole.

Optic Nerve Aplasia, Chorioretinal Hypoplasia, and Microcornea After In Utero Infection With Cytomegalovirus

Optic nerve aplasia (ONA) is a rare phenomenon characterized by absence of the optic nerve, retinal blood vessels, and retinal ganglion cells. The authors report a case of optic nerve aplasia in association with congenital cytomegalovirus (CMV) infection, conveyed through multimodal imaging including color fundus photography, fluorescein angiography, and B-scan ultrasonography. Furthermore, the authors review the common ocular findings and previously reported cases of ONA in congenital CMV infection. Screening and counseling can be performed to advise parents about the potential risks and severity of this rare clinical manifestation. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e171-e175.].

Vessel Tortuosity Cutoff Values Using the Modified ROPtool May Predict Need for Treatment in Retinopathy of Prematurity

BACKGROUND AND OBJECTIVE

To quantify vessel tortuosity among infants with retinopathy of prematurity (ROP).

PATIENTS AND METHODS

This was a retrospective study including 61 RetCam images from 33 infants. The laser treatment (LT) group included 17 infants who underwent laser for ROP. The no-treatment (NT) group included 16 infants. The modified ROPtool was used to calculate mean vessel tortuosity (MVT) and highest vessel tortuosity (HVT) for the participants and for the standard plus disease photograph from the Early Treatment for Retinopathy of Prematurity (ETROP) study.

RESULTS

The median MVT was 1.226 versus 1.056 for the LT and NT groups, respectively (P < .001). The median HVT was 1.346 versus 1.088 (P < .001). An MVT of 1.124 was 96.7% sensitive and 100% specific for identifying infants with treatment-requiring ROP. Both MVT and HVT cutoff values correctly captured plus disease in the standard ETROP trial photograph.

CONCLUSION

The modified ROPtool can be used to identify infants who have treatment-requiring ROP with a high level of sensitivity and specificity. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:215-220.].

Correlating Changes in the Macular Microvasculature and Capillary Network to Peripheral Vascular Pathologic Features in Familial Exudative Vitreoretinopathy

PURPOSE

To evaluate the macular microvasculature in patients with familial exudative vitreoretinopathy (FEVR) using OCT angiography (OCTA) and to assess for peripheral vascular changes using widefield fluorescein angiography (WFA).

DESIGN

Multicenter, retrospective, comparative, observational case series.

PARTICIPANTS

We identified 411 patients with FEVR, examined between September 2014 and June 2018. Fifty-seven patients with FEVR and 60 healthy controls had OCTA images of sufficient quality for analysis.

METHODS

Custom software was used to assess for layer-specific, quantitative changes in vascular density and morphologic features on OCTA by way of vessel density (VD), skeletal density (SD), fractal dimension (FD), vessel diameter index (VDI), and foveal avascular zone (FAZ). Widefield fluorescein angiography images were reviewed for peripheral vascular changes including capillary dropout, late-phase angiographic posterior and peripheral vascular leakage (LAPPEL), vascular dragging, venous-venous shunts, and arteriovenous shunts.

MAIN OUTCOME MEASURES

Macular microvascular parameters on OCTA and peripheral angiographic findings on WFA.

RESULTS

OCT angiography analysis of 117 patients (187 eyes; 92 FEVR patients and 95 control participants) demonstrated significantly reduced VD, SD, and FD and greater VDI in patients with FEVR compared with controls in the nonsegmented retina, superficial retinal layer (SRL), and deep retinal layer (DRL). The FAZ was larger compared with that in control eyes in the DRL (P < 0.0001), but not the SRL (P = 0.52). Subanalysis by FEVR stage showed the same microvascular changes compared with controls for all parameters. Widefield fluorescein angiography analysis of 95 eyes (53 patients) with FEVR demonstrated capillary nonperfusion in all eyes: 47 eyes (49.5%) showed LAPPEL, 32 eyes (33.7%) showed vascular dragging, 30 eyes (31.6%) had venous-venous shunts, and 33 eyes (34.7%) had arteriovenous shunts. Decreasing macular VD on OCTA correlated with increasing peripheral capillary nonperfusion on WFA. Decreasing fractal dimension on OCTA correlated with increasing LAPPEL severity on WFA.

CONCLUSIONS

Patients with FEVR demonstrated abnormalities in the macular microvasculature and capillary network, in addition to the peripheral retina. The macular microvascular parameters on OCTA may serve as biomarkers of changes in the retinal periphery on WFA.

Is it melanoma-associated retinopathy or drug toxicity? Bilateral cystoid macular edema posing a diagnostic and therapeutic dilemma

Purpose

To report the clinical presentation, multimodal imaging, and management of a patient with metastatic melanoma who presented with cystoid macular edema (CME).

Observations

We report a case of a 71-year-old Caucasian male with metastatic melanoma who presented with bilateral cystoid macular edema after being on treatment with a programmed T cell death ligand 1 inhibitor, MPDL3280, for 1 year. Multimodal imaging techniques, including color fundus photographs, autofluorescence, spectral domain optical coherence tomography (OCT), fluorescein angiography (Spectralis, Heidelberg, Germany), and spectral-domain OCT angiography (Zeiss; California, USA) were performed to evaluate the etiology of his CME and to monitor his response to treatment. Clinical examination and multimodal imaging revealed 1 + chronic vitreous cells, an epiretinal membrane, and mild macular edema in both eyes. Fundus autofluorescence showed paravenous hypoautofluorescence in the right eye and scattered hypoautofluorescent spots in the left eye. Optical coherence tomography angiography (OCTA) revealed mild drop out of superficial vessels in the peri-foveal region bilaterally. These findings were concerning for melanoma-associated retinopathy, drug-related uveitis, or activation of a previous chronic autoimmune process. The patient was started on prednisone 30 mg oral daily and ketorolac tromethamine 0.5% 1 drop four times daily. He was then treated with bilateral sustained-release dexamethasone intravitreal implants (Ozurdex). He had complete resolution of CME, and was tapered off of oral steroids within 6 weeks.

Conclusions and Importance

Melanoma-associated retinopathy can be accompanied by CME, which presents a diagnostic and therapeutic dilemma in cases where a new drug has been recently initiated. By treating the condition locally, the ophthalmologist may be able to taper systemic immunosuppression more quickly.

THE SECOND BLIND SPOT: SMALL RETINAL VESSEL VASCULOPATHY AFTER VACCINATION AGAINST NEISSERIA MENINGITIDIS AND YELLOW FEVER

PURPOSE

To describe a case of small retinal vessel vasculopathy postvaccination.

METHODS

We report the case of a 41-year-old white man who presented with a "second blind spot," describing a nasal scotoma in the right eye that started 4 days after vaccinations against Neisseria meningitidis and the yellow fever virus, and after a 2-month period of high stress and decreased sleep. Clinical examination, Humphrey visual field testing, and multimodal imaging with fundus photographs, autofluorescence, fluorescein angiography, and spectral domain optical coherence tomography and angiography were performed.

RESULTS

Clinical examination revealed a well-circumscribed, triangular area of retinal graying of about 1-disk diameter in size, located at the border of the temporal macula. This corresponded to a deep scotoma similar in size to the physiologic blind spot on Humphrey visual field 24-2 testing. There was mild hypoautofluoresence of this lesion on autofluorescence, hypofluorescence on fluorescein angiography, and focal attenuation of a small artery just distal to the bifurcation of an artery supplying the involved area. Spectral domain optical coherence tomography through the lesion conveyed hyperreflectivity most prominent in the inner and outer plexiform layers, with extension of the hyperreflectivity into the ganglion cell and inner nuclear layers. Spectral domain optical coherence tomography angiography demonstrated arteriolar and capillary dropout, more pronounced in the superficial retinal layer compared to the deeper retinal layer. At 1-month follow-up, his scotoma improved with monitoring, with reduction from -32 dB to -7 dB on Humphrey visual field testing. There was clinical resolution of the area of graying and decreased hyperreflectivity on spectral domain optical coherence tomography, with atrophy of the inner retina. Spectral domain optical coherence tomography angiography showed progression of arteriolar and capillary dropout, more so in the superficial than in the deep capillary plexus.

CONCLUSION

We describe a case of small artery occlusion in a previously healthy patient, 4 days after vaccination against N. meningitidis and yellow fever. Fluorescein angiography yielded greater diagnostic value than OCTA for evaluating the occlusion, whereas spectral domain optical coherence tomography angiography enabled better visualization of capillary dropout and layer-specific assessment. Further research is required to determine whether vaccination in general, or directed specifically at N. meningitidis or yellow fever, is associated with small vessel vasculopathy and the underlying pathogenesis.

The tipping point: Tamoxifen toxicity, central serous chorioretinopathy, and the role of estrogen and its receptors

Purpose

To describe a case of tamoxifen toxicity superimposed on central serous chorioretinopathy (CSCR). We review the role of estrogen and the effect of tamoxifen on ocular tissues.

Observations

A 32-year-old Hispanic female with infiltrating ductal carcinoma of the left breast (T2N1M0, triple-positive), status post chemotherapy and bilateral mastectomy, presented with complaint of a floater and decreased central vision of the right eye (OD). Symptoms began three weeks after initiating tamoxifen and five months after the last cycle of chemotherapy and dexamethasone. Visual acuity (VA) was 20/30 OD at presentation. Clinical examination and multimodal imaging revealed subretinal fluid (SRF) and pigment epithelial detachment (PED) suggestive of CSCR. After one month of monitoring, VA improved to 20/20; there was SRF resolution, small PED, and focal ellipsoid zone (EZ) band loss. Two weeks later, after undergoing surgery and starting a topical steroid, she returned with count fingers (CF) VA and large SRF OD. Steroid cessation improved SRF after one month, but VA was unchanged. Tamoxifen was discontinued, and VA improved to 20/100 with near-complete resolution of SRF at three weeks, and significant reduction in choroidal thickness at two months. At final follow-up, VA was 20/200, and there was focal EZ band loss sub-foveally, minimal SRF, and small PED.

Conclusions and Importance

Treatment with tamoxifen may lead to ocular toxicity and can complicate the recovery course of patients affected with CSCR. Variations in levels of the estrogen receptor-alpha (ER-α) and treatment with tamoxifen (ER-α partial agonist) may lead to loss of the protective effect of estrogen in the retinal pigment epithelial cells in premenopausal women. Furthermore, tamoxifen toxicity can lead to focal photoreceptor loss. Treatment in these cases should be coordinated together with the oncologist.

Promoting filopodial elongation in neurons by membrane-bound magnetic nanoparticles

Filopodia are 5-10 μm long processes that elongate by actin polymerization, and promote axon growth and guidance by exerting mechanical tension and by molecular signaling. Although axons elongate in response to mechanical tension, the structural and functional effects of tension specifically applied to growth cone filopodia are unknown. Here we developed a strategy to apply tension specifically to retinal ganglion cell (RGC) growth cone filopodia through surface-functionalized, membrane-targeted superparamagnetic iron oxide nanoparticles (SPIONs). When magnetic fields were applied to surface-bound SPIONs, RGC filopodia elongated directionally, contained polymerized actin filaments, and generated retrograde forces, behaving as bona fide filopodia. Data presented here support the premise that mechanical tension induces filopodia growth but counter the hypothesis that filopodial tension directly promotes growth cone advance. Future applications of these approaches may be used to induce sustained forces on multiple filopodia or other subcellular microstructures to study axon growth or cell migration. From the clinical editor: Mechanical tension to the tip of filopodia is known to promote axonal growth. In this article, the authors used superparamagnetic iron oxide nanoparticles (SPIONs) targeted specifically to membrane molecules, then applied external magnetic field to elicit filopodial elongation, which provided a tool to study the role of mechanical forces in filopodia dynamics and function.

Magnetic field-guided cell delivery with nanoparticle-loaded human corneal endothelial cells

To improve the delivery and integration of cell therapy using magnetic cell guidance for replacement of corneal endothelium, here we assess magnetic nanoparticles' (MNPs') effects on human corneal endothelial cells (HCECs) in vitro. Biocompatible, 50 nm superparamagnetic nanoparticles endocytosed by cultured HCECs induced no short- or long-term change in viability or identity. Assessment of guidance of the magnetic HCECs in the presence of different magnet shapes and field strengths showed a 2.4-fold increase in delivered cell density compared to gravity alone. After cell delivery, HCECs formed a functional monolayer, with no difference in tight junction formation between MNP-loaded and control HCECs. These data suggest that nanoparticle-mediated magnetic cell delivery may increase the efficiency of cell delivery without compromising HCEC survival, identity or function. Future studies may assess the safety and efficacy of this therapeutic modality in vivo. From the clinical editor: The authors show in this article that magnetic force facilitates the delivery of human corneal endothelial cells loaded by superparamagnetic nanoparticles to cornea, without changing their morphology, identity or functional properties. This novel idea can potentially have vast impact in the treatment of corneal endothelial dystrophies by providing self-endothelial cells after ex-vivo expansion.

MULTIMODAL IMAGING OF GEOGRAPHIC AREAS OF RETINAL DARKENING

PURPOSE

To describe the clinical and multimodal imaging characteristics of a patient with unilateral asymptomatic dark retinal lesions corresponding to ellipsoid zone hyporeflectivity on optical coherence tomography (OCT).

METHODS

The authors report a case of a 35-year-old man with HIV who presents with asymptomatic dark geographic retinal lesions corresponding to ellipsoid zone hyporeflectivity on OCT. Multimodal imaging techniques, including fundus color and widefield photographs, autofluorescence, spectral domain OCT (Spectralis, Heidelberg, Germany), prototype spectral domain OCT (Carl Zeiss Meditec, Dublin, CA) with OCT angiography, and en face images, were performed to evaluate and characterize the morphology of these lesions.

RESULTS

Clinical examination and multimodal imaging reveal geographic darkening of the retina. Optical coherence tomography conveys hyporeflectivity of the ellipsoid zone band, which occurs abruptly and is present only in the areas of geographic retinal darkening. Optical coherence tomographic angiography shows a qualitatively similar appearance of the vasculature from the superficial retina through the avascular retina and the choriocapillaris, on both sides of the demarcation of retinal darkening, and also as compared to the unaffected eye. En face images from spectral domain OCT reveal an abrupt darkening of the tissue that localizes and is limited to the ellipsoid zone, with similar topographic appearance across the demarcation line.

CONCLUSION

Geographic areas of darkening with photoreceptor hyporeflectivity have been described previously as "dark without pressure." In this case, the authors demonstrate photoreceptor hyporeflectivity that localizes to the clinically darkened areas, without topographic qualitative differences on en face spectral domain OCT images. The authors term these dark areas as geographic areas of retinal darkening because of ellipsoid nonreflectivity (GARDEN) spots.

Mitochondrial dynamics regulate growth cone motility, guidance, and neurite growth rate in perinatal retinal ganglion cells in vitro

PURPOSE

Retinal ganglion cell (RGC) death and failed axonal regeneration after trauma or disease, including glaucomatous and mitochondrial optic neuropathies, are linked increasingly to dysfunctional mitochondrial dynamics. However, how mitochondrial dynamics influence axon growth largely is unstudied. We examined intrinsic mitochondrial organization in embryonic and postnatal RGCs and the roles that mitochondrial dynamics have in regulating neurite growth and guidance.

METHODS

RGCs were isolated from embryonic day 20 (E20) or postnatal days 5 to 7 (P5-7) Sprague-Dawley rats by anti-Thy1 immunopanning. After JC-1 loading, mitochondria were analyzed in acutely purified RGCs by flow cytometry and in RGC neurites by fluorescence microscopy. Intrinsic axon growth was modulated by overexpressing Krüppel-like family (KLF) transcription factors, or mitochondrial dynamics were altered by inhibiting dynamin related protein-1 (DRP-1) pharmacologically or by overexpressing mitofusin-2 (Mfn-2). Mitochondrial organization, neurite growth, and growth cone motility and guidance were analyzed.

RESULTS

Mitochondrial dynamics and function are regulated developmentally in acutely purified RGCs and in nascent RGC neurites. Mitochondrial dynamics are modulated differentially by KLFs that promote or suppress growth. Acutely inhibiting mitochondrial fission reversibly suppressed axon growth and lamellar extension. Inhibiting DRP-1 or overexpressing Mfn-2 altered growth cone responses to chondroitin sulfate proteoglycan, netrin-1, and fibronectin.

CONCLUSIONS

These results support the hypothesis that mitochondria locally modulate signaling in the distal neurite and growth cone to affect the direction and the rate of neurite growth.