Relationship between nonperfusion area from widefield optical coherence tomography angiography and macular vascular parameters in diabetic retinopathy.

PURPOSE: To evaluate the relationship between the nonperfusion area (NPA) from widefield optical coherence tomography angiography (OCTA) and macular vascular parameters in diabetic retinopathy (DR). METHODS: In total, 51 eyes from 51 patients with proliferative DR (PDR) or moderate/severe non-PDR were included. Widefield OCTA using the Zeiss Plex Elite 9000 was performed. A semi-automatic algorithm calculated the percentages of the NPA within the total image. Macular OCTA (3 × 3 mm and 6 × 6 mm area) was scanned using the RTVue-XR Avanti. Vessel density (VD) was automatically separated into the superficial (SCP) and deep capillary plexus (DCP), and foveal avascular zone (FAZ) measurements were computed according to the parafoveal (1-3 mm) and perifoveal (3-6 mm) regions. RESULTS: A negative correlation was found between the average VD of the SCP and DCP obtained 3 × 3 mm and 6 × 6 mm area and the NPA. Multiple regression analysis revealed that the temporal-perifoveal region most negatively correlated with the NPA (r = - 0.55, p < 0.0001). No correlation was found between FAZ measurements and DR severity (area, p = 0.07; perimeter, p = 0.13). CONCLUSION: Diabetic macular nonperfusion was significantly associated with the NPA from widefield OCTA. In particular, the temporal-perifoveal DCP disorder may be a sensitive indicator of wide NPA.

EVALUATION OF THE RETINAL HAZARD WITH 3D DIGITALLY ASSISTED VISUALIZATION SYSTEM AND CONVENTIONAL MICROSCOPE IN MACULAR SURGERIES.

PURPOSE: To investigate the retinal light hazard during macular surgery using a digital three-dimensional visualization system (3D) and a conventional microscope (CM). DESIGN: Experimental study and retrospective evaluation of a case-control study. SUBJECTS: A total of 20 and 10 patients who underwent pars plana vitrectomy for epiretinal membrane using 3D and CM, respectively. METHODS: Spectral irradiances of endoilluminators were measured for representative settings used during core vitrectomy and macular manipulations with 3D and CM. From the medical record of the patients, time needed for core vitrectomy and macular manipulations was extracted. The total retinal light hazard index and the macular hazard index were calculated based on the spectral irradiances weighted by the standard functions. Total retinal light hazard index, macular hazard index, and the number of cases that exceeded the maximum permissible radiant power exposure were compared between the two groups. RESULTS: The spectral irradiance were 1.6 and 3.9 mW/cm 2 for core vitrectomy and 3.4 and 8.1 mW/cm 2 for macular manipulations using typical settings for 3D and CM groups, respectively. The total retinal light hazard index ranged from 4.31 kJ/m 2 to 17.37 kJ/m 2 for 3D and 11.09 kJ/m 2 to 27.70 kJ/m 2 for CM groups, respectively, whereas the macular hazard index ranged from 2.93 kJ/m 2 to 14.58 kJ/m 2 for 3D and from 6.84 kJ/m 2 to 23.55 kJ/m 2 for CM, respectively ( P < 0.001). One (5%) and 6 (60%) pars plana vitrectomy cases exceeded the threshold limits with 3D and CM groups, respectively ( P < 0.05, chi-square test). CONCLUSION: The 3D digitally assisted visualization system offers significantly safer macular surgery compared with the CM, considering the potential retinal hazard.

Primary isolated amyloidosis in the extraocular muscle as a rare cause of ophthalmoplegia: A case report and literature review.

PURPOSE: To report a case of external ophthalmoplegia due to an uncommon form of amyloidosis exclusively affecting the lateral rectus muscle, and to discuss the clinical manifestation, diagnostic challenges, and management pitfalls of isolated amyloidosis in the extraocular muscle. OBSERVATIONS: A 64-year-old woman presented with diplopia in her left gaze lasting for six months. She had orthophoria in the primary position and abduction limitation in the left eye. Routine laboratory examinations were unremarkable. Orbital magnetic resonance imaging showed fusiform enlargement of the left lateral rectus muscle, without tendon involvement. Extraocular muscle biopsy was recommended to make a diagnosis, which revealed amyloid deposition in the lateral rectus muscle. A systemic work-up showed no evidence of systemic amyloidosis. Therefore, a diagnosis of primary isolated amyloidosis was made. Orthophoria in the primary position and diplopia in the lateral gaze persisted at the six-month follow-up. CONCLUSIONS AND IMPORTANCE: Atypical extraocular muscle enlargement should alert clinicians to the need for tissue biopsy to identify uncommon etiologies, such as amyloidosis. There are no pathognomonic or radiological features to distinguish localized from systemic amyloidosis. Therefore, if amyloidosis of the extraocular muscles is diagnosed, a systemic work-up is needed to rule out systemic amyloidosis, which is potentially life-threatening.

Circumpapillary collateral vessel development in iatrogenic central retinal artery occlusion observed using OCT angiography.

PURPOSE: It has been reported that peripapillary loops develop after central retinal artery occlusion (CRAO). Although cilioretinal anastomoses have been shown by fluorescein angiography (FA) and indocyanine green angiography, these examinations cannot confirm the structural continuity between the retinal arteries and the posterior ciliary arteries. In the current report, we followed a patient with iatrogenic CRAO in which circumpapillary collaterals formed and assessed the connection between these two vascular systems using optical coherence tomography angiography (OCTA). OBSERVATION: Iatrogenic CRAO developed in the left eye of a 30-year-old woman during preoperative embolization of a convexity meningioma. FA and OCTA showed complete impairment of the retinal circulation. Two weeks after this event, OCTA images showed flow in the retinal vessels and the beginning of collateral vessel development on the optic disc margin. Six months later, OCTA images showed that these circumpapillary collaterals connected branches of the retinal arteries with the vessels supplying the optic disc, which originate from the posterior ciliary arteries. CONCLUSION AND IMPORTANCE: OCTA aided our understanding of the three-dimensional configuration of the circumpapillary collaterals that developed after iatrogenic CRAO, which included anastomosis of the retinal and posterior ciliary artery systems. OCTA is useful for noninvasively monitoring the status of retinal circulatory dynamics after iatrogenic CRAO.