Macular choroidal thickness: evaluation of variability among measurements and assessment of predictive value of glaucomatous visual field damage

Introduction: To investigate the relationship between the choroidal circulation and glaucoma, assessing macular choroidal thickness (MCT) as a predictive value of glaucomatous visual field damage. Methods: Twenty primary open-angle glaucoma patients were recruited. Patients underwent two SS-OCTs scans: one with DRI OCT (Topcon) and the other with PLEX Elite 9000 (Zeiss). Standard OCT parameters were acquired by DRI OCT, while MCT was manually measured in 5 points on Plex ELITE 9000 images. The relationship among MCT, standard OCT parameters and visual field indices were evaluated. Pearson’s r correlation was calculated to evaluate these relationships. Reproducibility of measurements was analyzed. Results: MCT measurements showed a good intra- and inter-observer repeatability. A negative correlation appeared between MCT and body mass index (BMI) (r = -0.518, p=0.023). Mean deviation showed a statistically significant correlation with MCT measured at sub-foveal and at 1000 µm nasally (r = 0.50, p=0.03 and r = 0.52, p=0.023). A correlation was found between the two MCT (Zeiss vs Topcon) measurements and between MCT and peripapillary choroidal thickness (r = 0.944 and r = 0.740, p<0.001, respectively). Conclusions: A good intra- and inter-observer reproducibility was found. MCT showed a weak predictive value of glaucomatous visual field damage. A significant correlation was found between MCT and BMI.

Peripheral extent of the choroidal circulation by ultra-widefield indocyanine green angiography in healthy eyes

AimTo analyse the peripheral extent of choroidal circulation using ultra-widefield (UWF) indocyanine green angiography (ICGA) in healthy eyes.MethodsUWF ICGA images of 55 eyes of 36 healthy subjects were captured using the Optos California (Optos, Dunfermline, United Kingdom) in this prospective observational study. Images were analysed to locate the peripheral extent of the visible choroidal circulation, and the boundary was marked in ImageJ (v1.52). Each pixel annotated as the border of the choroidal circulation was projected individually to its anatomically correct location on the three-dimensional model eye, and spherical trigonometry was applied (using the Optos software) to calculate its respective radial distance from the centre of the optic disc in metric units (corrected by stereographic projection) for each quadrant.ResultsThe mean area of the peripheral extent was estimated to be 893.2 mm2 (95% CI: 844.2 to 942.3 mm2). The mean distance (range) of this boundary from optic nerve centre was 18.22 mm (95% CI: 14.0 to 23.14 mm). Multiple regression analysis with age, gender, axial length or ethnicity showed no relationship. There was excellent inter-grader reproducibility, with intraclass correlation coefficients of 0.95 (95% CI: 0.80 to 0.99, p<0.001) for distance and 0.99 (95% CI: 0.988 to 0.999, p<0.001) for area measurements.ConclusionsThe peripheral choroidal boundary may be defined using UWF ICGA. Knowledge of the normal extent and its variability is essential to understand the impact of disease on the choroidal vasculature.

Ocular Blood Flow Changes Impact Visual Acuity Gain after Surgical Treatment for Idiopathic Epiretinal Membrane

Background: Idiopathic epiretinal membrane (iERM) is a common eye disease, which can be treated by surgical removal of the fibrotic tissue. Morphological outcome is generally evaluated by optical coherence tomography (OCT). Here, we investigate the impact of surgery on hemodynamics of the posterior pole, using OCT angiography (OCTA). Methods: Patients with unilateral iERM and indication for treatment were included. OCT and OCTA images of the posterior pole were obtained preoperatively and 3-months after 23G vitrectomy with membrane peeling. Parameters of interest included full retinal perfusion, choriocapillaris perfusion (CCP), Sattler’s layer perfusion (SLP), and Haller’s layer perfusion, which were evaluated longitudinally and also compared to unaffected fellow eyes. Using these parameters, multiple regression analyses were used to predict visual outcomes. Results: Sixty-three iERM eyes were recruited, which initially showed a significant bigger central retinal thickness (p < 0.001) and total macular volume (TMV) (p < 0.001) compared to fellow eyes, while perfusion parameters were alike. Three months later, treated eyes had a statistically significant thicker subfoveal choroid (p = 0.006) and showed an increase of CCP (p = 0.003), while SLP decreased (p = 0.014). Lower preoperative TMV and higher SLP were associated with better postoperative visual outcome. Conclusion: In this OCTA study, iERM itself does not affect the choroidal circulation. However, preoperative choroidal circulation will be a biomarker to know the influence on the choroidal circulation after ERM surgery and may be considered as a predictor for visual outcome.

Ocular complications in pre-eclampsia

Exudative retinal detachment (ERD) is a rare complication of pre-eclampsia in pregnancy. The pathophysiology is uncertain but it is thought to be due to microvasculopathy involving the choroidal circulation. We report a case of a 36-year-old woman with underlying essential hypertension complicated with impending eclampsia in her third trimester of pregnancy. She developed bilateral bullous ERD at 34 weeks of gestation. Following emergency caesarean section, her blood pressure normalised after 10 days and the ERD partially resolved spontaneously after 30 days. Her best-corrected visual acuity improved from hand movement (HM) in the right eye and counting finger (CF) in the left eye to 6/24 bilaterally after 30 days postpartum. Pre-eclampsia-induced ERD is usually managed conservatively and the prognosis is usually good.

Polypoidal Choroidal Vasculopathy

Polypoidal choroidal vasculopathy (PCV) is an age-related macular degeneration (AMD) subtype and is seen particularly in Asians. There is a disparity in response to intravitreal anti-vascular endothelial growth factor (VEGF) treatments between PCV and typical AMD, and the preferred treatment for PCV has remained unclear. Recent researches suggest that PCV belongs to a condition characterized by pachychoroid and disturbance in the choroidal circulation seems to be central to its pathogenesis. In this review, we summarize the clinical and imaging features, diagnostic criteria, and current management guidelines of PCV.

A Case of Idiopathic Orbital Inflammation with Shallow Anterior Chamber and Choroidal Detachment

We report a case of idiopathic orbital inflammation with a shallow anterior chamber and choroidal detachments. This study involved an 87-year-old female patient who presented at our department after becoming aware of the progression of diplopia. Examination of the patient’s right eye revealed proptosis, as well as conjunctival edema with dilated and tortuous blood vessels. The right-eye anterior chamber was shallow, and fundus examination revealed marked choroidal detachments. Magnetic resonance imaging revealed enlargement of the right-orbit extraocular muscles and a suspected compression of the right-orbit superior and inferior ophthalmic veins, yet no expansion of the cavernous sinus. We diagnosed the patient as having idiopathic orbital inflammation in her right orbit, and subsequently started corticosteroid therapy. One week after initiating treatment, the anterior chamber was found to be nearing a normal depth, and the choroidal detachments were found to have disappeared. Our findings revealed that the inflammatory swelling of the extraocular muscle due to idiopathic orbital inflammation resulted in compression of the right-orbit superior and inferior ophthalmic veins, thus leading to an apparent choroidal circulation disorder that presented with a shallow anterior chamber and marked choroidal detachments.

Choroidal changes after intravitreal injection of interferon alpha-2b

Intravitreal injection of interferon alpha-2b (IFN-α2b) is used to treat uveitis but its effect on the choroid is unknown. We histologically evaluated the choroidal changes after intravitreal injection of IFN-α2b. We compared histological samples of IFN-α2b-injected eyes to eyes with lipopolysaccharide (LPS)-induced uveitis and eyes injected with balanced salt solution (BSS) as controls. Rabbit eyes received intravitreal injections of BSS, IFN-α2b, or LPS, and enucleation was done seven days later. Choroidal changes were evaluated on histological cut sections. The thickness of the choroid was measured in micrometer and the severity of inflammation was scored. The mean maximum choroidal thickness was significantly greater in the IFN-α2b group in comparison to the LPS and BSS groups ( P < 0.001). The mean minimum choroidal thickness was also significantly greater in the IFN group compared to the BSS group ( P = 0.009). The observed changes were mainly due to vasodilation rather than interstitial fluid retention or inflammation. Mild inflammatory cell infiltration was observed in the choroid of four eyes in the IFN group and of three eyes in the LPS group. No inflammation was seen in the control group. The difference in inflammatory cell infiltration between the LPS and IFN groups was not statistically significant. Significant choroidal hyperemia was present after injection of IFN-α2b. This fact may suggest for some pharmacological applications of IFN-α2b when increased choroidal circulation is needed. However, further studies are required to elucidate the mechanisms involved. Impact statement Type I interferons are proteins that are naturally secreted by cells in response to certain stimuli. They are approved for medical use to regulate immune responses in many disease states. Our findings of increased choroidal circulation after treatment of the eye with interferon alpha-2b indicate a possible effect of this cytokine on blood circulation. This is a novel finding that needs further investigation to elucidate mechanisms and applications.