Optical coherence tomography angiography analysis of retinal vascular plexuses and choriocapillaris in patients with type 1 diabetes without diabetic retinopathy

AIMS

To analyze retinal vascular plexuses and choriocapillaris by optical coherence tomography angiography (OCT-A) and retinal nerve fiber layer and ganglion cell layer (GCL) by structural optical coherence tomography (OCT) in patients with type 1 diabetes mellitus (T1DM) without diabetic retinopathy (DR).

METHODS

A total of 25 eyes of 25 consecutive T1DM patients without signs of DR were prospectively recruited and compared to 25 healthy subjects (control eyes). All patients underwent OCT-A (CIRRUS HD-OCT model 5000, Carl Zeiss Meditec, Dublin, CA) and structural OCT. Qualitative and quantitative analyses with vessel density were performed on OCT-A images in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris for all patients.

RESULTS

By means of OCT-A, a rarefaction of the perifoveal capillary network in SCP was detected in 7 out of 25 eyes. No significant difference was found in FAZ area of both SCP and DCP comparing diabetic and control groups. By analyzing the DCP, diabetic eyes revealed a significant decreased vessel density compared to control eyes [0.464 ± 0.016 and 0.477 ± 0.014, respectively (p = 0.005)]. Instead, no significant difference was found in the vessel density of all-retina plexus, SCP and choriocapillaris. By RFNL and GCL thickness analysis, no significant differences were disclosed between diabetics and healthy subjects.

CONCLUSIONS

We demonstrated the ability of OCT-A to disclose early vascular alterations in patients with T1DM diagnosed as without any signs of DR on the basis of fundus biomicroscopy. Our results also suggest that microvascular changes could precede detectable damage of diabetic neuroretinopathy.

Choroidal Vascularity Index: An In-Depth Analysis of This Novel Optical Coherence Tomography Parameter

Remarkable improvements in optical coherence tomography (OCT) technology have resulted in highly sophisticated, noninvasive machines allowing detailed and advanced morphological evaluation of all retinal and choroidal layers. Postproduction semiautomated imaging analysis with dedicated public-domain software allows precise quantitative analysis of binarized OCT images. In this regard, the choroidal vascularity index (CVI) is emerging as a new imaging tool for the measurement and analysis of the choroidal vascular system by quantifying both luminal and stromal choroidal components. Numerous reports have been published so far regarding CVI and its potential applications in healthy eyes as well as in the evaluation and management of several chorioretinal diseases. Current literature suggests that CVI has a lesser variability and is influenced by fewer physiologic factors as compared to choroidal thickness. It can be considered a relatively stable parameter for evaluating the changes in the choroidal vasculature. In this review, the principles and the applications of this advanced imaging modality for studying and understanding the contributing role of choroid in retinal and optic nerve diseases are discussed. Potential advances that may allow the widespread adoption of this tool in the routine clinical practice are also presented.

Optical Coherence Tomography Angiography: A Useful Tool for Diagnosis of Treatment-Naïve Quiescent Choroidal Neovascularization

PURPOSE

To describe the optical coherence tomography angiography (OCT-A) features of treatment-naïve quiescent choroidal neovascularization (CNV) secondary to age-related macular degeneration, and to estimate the detection rate for neovascularization by means of OCT-A.

DESIGN

Diagnostic tool validity assessment.

METHODS

Treatment-naïve quiescent CNV were identified from a pool of patients at 2 retina referral centers. Patients underwent a complete ophthalmologic examination including fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and OCT-A. Detection rates of CNV by means of OCT-A were estimated with a second cohort of patients without CNV (negative controls).

RESULTS

Twenty-two eyes of 20 consecutive patients with quiescent CNV were included. In 4 out of 22 eyes it was not possible to classify the CNV "shape," "core," "margin," and "location," either because the vascular network was not clearly shown (3 cases) or because it was not visible at all (1 case). CNV shape on OCT-A was rated as circular in 8 eyes and irregular in 10 eyes. CNV core was visible in 2 eyes. CNV margin was considered as well defined in 15 eyes and poorly defined in 3 eyes. CNV margin showed small loops in 9 eyes and large loops in the other 6 eyes. CNV location was foveal-sparing in 12 eyes. Sensitivity and specificity of quiescent CNV detection by OCT-A turned out to be 81.8% and 100%, respectively.

CONCLUSIONS

OCT-A allows the clinician to noninvasively identify treatment-naïve quiescent CNV and may be considered as a useful tool to guide the frequency of return visits and, possibly, make treatment decisions.

The Expanded Spectrum of Perifoveal Exudative Vascular Anomalous Complex

PURPOSE

To expand our understanding of the uncommon entity, referred to as perifoveal exudative vascular anomalous complex (PEVAC) by describing multimodal imaging findings, including optical coherence tomography angiography (OCT-A).

DESIGN

Retrospective cohort study.

METHODS

Patients diagnosed with PEVAC were identified at 4 retina referral centers worldwide and underwent complete ophthalmologic examination including structural OCT, OCT-A, fluorescein angiography (FA), and indocyanine green angiography (ICGA). Demographics and clinical findings were analyzed at baseline and at available follow-ups.

RESULTS

Fifteen eyes (15 patients, mean age 73 ± 13 years) were included. Six of 15 eyes were diagnosed with coincident age-related macular degeneration (AMD) and 2 with myopic macular degeneration. On fundus examination PEVAC presented as a large perifoveal isolated aneurysm, unifocal in 12 of 15 eyes, associated with small retinal hemorrhages and intraretinal exudation. On structural OCT, PEVAC appeared as a round hyperreflective lesion with hyporeflective lumen, typically surrounded by intraretinal cystic spaces. Dye angiography demonstrated a well-defined hyperfluorescent lesion with variable leakage on FA and without leakage on ICGA. OCT-A showed flow signal correlating with the aneurysmal lesion connecting to retinal capillary plexuses. Seven patients were followed for 13.0 ± 10.5 months with no evidence of functional/anatomic changes. Three patients underwent anti-vascular endothelial growth factor (VEGF) intravitreal injections without improvement. Two eyes were associated with a type 3 neovascularization eccentric to PEVAC.

CONCLUSIONS

PEVAC is an isolated, perifoveal, aneurysmal abnormality, occurring in otherwise healthy patients who may manifest other macular disease including AMD and myopic macular degeneration. PEVAC did not typically respond to anti-VEGF therapy, and may be associated with type 3 neovascularization.

Treatment-Naïve Quiescent Choroidal Neovascularization in Geographic Atrophy Secondary to Nonexudative Age-Related Macular Degeneration

PURPOSE

To describe the characteristics and natural history of quiescent choroidal neovascularization (CNV) in geographic atrophy (GA) secondary to nonexudative age-related macular degeneration (AMD) through multimodal imaging.

DESIGN

Retrospective observational case series.

METHODS

Patients diagnosed with quiescent CNV were analyzed in 2 high-volume referral centers. Imaging features obtained using fluorescein angiography (FA), indocyanine green angiography (ICGA), structural optical coherence tomography (OCT), and OCT angiography (OCT-A) were noted at first presentation and during the study period.

RESULTS

Nineteen eyes of 19 patients were included. Mean (+SD) follow-up was 45.7 ± 14.7 months. Quiescent CNV appeared as an ill-defined hyperfluorescent lesion without leakage or pooling of dye in the late phase of FA. On ICGA, quiescent CNV appeared as a distinct area of hyperfluorescence (vascular network) in early to intermediate frames and as a hyperfluorescent plaque in the late frame (late plaque). OCT-A revealed a flow signal beneath the small irregular elevation of the retinal pigment epithelium at the site of the quiescent CNV visualized by structural OCT. During the study period, 5 of the 19 CNV patients developed exudation. The remainder showed specific alterations in both structural OCT and OCT-A imaging. At last follow-up, 92% of the quiescent CNV seemed to cover the area spared from atrophy.

CONCLUSIONS

The characteristics of the quiescent CNVs were very similar to those already described for intermediate AMD, although they had several specific features in the context of GA.

Nascent Type 3 Neovascularization in Age-Related Macular Degeneration

PURPOSE

To describe the preclinical and very early stages of type 3 neovascularization using multimodal retinal imaging to expand our understanding of the pathogenesis of this disorder and potentially to prevent late treatment.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients diagnosed with treatment-naïve type 3 neovascularization in the setting of age-related macular degeneration were identified at 4 retina referral centers. Inclusion criteria were: patients older than 55 years with at least 1 OCT and OCT angiography (OCTA) examination before the onset of clinically active type 3 neovascularization (i.e., preclinical stage).

METHODS

Patients underwent a complete ophthalmologic examination including at least OCT and OCTA at the baseline and preclinical stage examinations, and dye angiographies when available. Demographics and clinical findings were analyzed.

MAIN OUTCOME MEASURES

Description of multimodal imaging features of nascent type 3 neovascularization.

RESULTS

Fifteen eyes (15 patients; mean age, 83 ± 9 years) were included. At the baseline, mean BCVA was 0.32 ± 0.17 logarithm of the minimum angle of resolution and central macular thickness was 313 ± 50 μm. Preclinical (i.e., prebaseline) structural OCT illustrated the presence of intraretinal hyperreflective foci (HRF) at the site of type 3 neovascularization development in all patients. These foci were characterized by hyperfluorescence on dye angiography and by detectable flow on OCTA, identified with either the avascular slab (20%) or with both the deep retinal capillary plexus (DCP) and avascular slabs (80%). Typically, HRF with detectable flow on OCTA were characterized by the absence of intraretinal exudation (or very mild microcystic changes) until the lesion progressed from the DCP into the retinal pigment epithelium (RPE) and sub-RPE space. Of note, in 1 patient we observed the complete resolution of HRF despite the presence of OCTA flow and dye angiography hyperfluorescence detected at the preclinical stage examination.

CONCLUSIONS

Hyperreflective foci on structural OCT may represent early intraretinal neovascularization originating from the DCP, namely nascent type 3 neovascularization; these lesions can progress to active type 3 neovascularization or more rarely may regress without functional impairment. An advanced multimodal imaging approach is useful in detecting nascent type 3 lesions, which should be followed up carefully and treated as soon as possible if flow progresses to the RPE and sub-RPE space to prevent progression to late stages.

Quantitative changes in the ageing choriocapillaris as measured by swept source optical coherence tomography angiography

Aim

To analyse quantitative optical coherence tomography angiography (OCTA) parameters of choriocapillaris (CC) at the foveal, perifoveal and parafoveal regions in healthy subjects of different age.

Methods

In this observational cross-sectional study, consecutive healthy subjects underwent swept source OCTA (PLEX Elite 9000, Carl Zeiss Meditec, USA). 3×3 mm and 6×6 mm scans centred on the fovea were acquired analysed and postprocessed with thresholding and binarisation processes. The main outcome measures included CC quantitative OCTA features (perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI)) at the foveal, perifoveal and parafoveal regions, and their relationship with age.

Results

Seventy-two eyes (72 patients, mean age 47.4±19.2 years, mean axial length 24.0±0.7 mm) were included. The mean PD was statistically lower in the foveal region compared with the parafoveal region in 3×3 mm scans (p=0.009). In subjects aged 70–80, PD of the foveal region was significantly reduced compared with the perifoveal region in 6×6 mm scans (p=0.008). A strong negative correlation was found between PD and ageing in the foveal, parafoveal and perifoveal regions (p<0.001 in all analyses). Furthermore, PD in the nasal-perifoveal region was significantly lower than the temporal-perifoveal region (p=0.005). No significant correlation was found between VLD and age in all regions, whereas VDI was strictly correlated with age (p<0.001).

Conclusions

We reported in vivo a strong negative correlation between PD and ageing in the CC of healthy subjects. This reduction seems related to a reduced diameter, and not to a reduced number, of capillaries. The age-related changes were higher in the central area compared with the perifoveal area.

Ultra-wide-field fluorescein angiography in diabetic retinopathy: a narrative review

Fluorescein angiography (FA) is a useful examination in patients suffering from diabetic retinopathy (DR). Traditional angiograms explore 30°–50° of the retina at once; however, visualization of peripheral retina is fundamental in order to assess nonperfused areas, vascular leakage, microvascular abnormalities, and neovascularizations. In order to expand the field of view, wide-field and ultra-wide-field imaging has been developed allowing to image up to 200° of retinal surface in one single shot. The aim of this narrative review was to provide an overview of the role of the most recent technique of ultra-wide-field fluorescein angiography in DR.

Multimodal Imaging Assessment of Vascular and Neurodegenerative Retinal Alterations in Type 1 Diabetic Patients without Fundoscopic Signs of Diabetic Retinopathy

The aim of this cross-sectional case-control study is to investigate the possible presence of vascular/neurodegenerative alterations in the retina of type 1 diabetes mellitus (T1DM) patients without diabetic retinopathy (DR). Thirty-four eyes of 34 consecutive T1DM without DR (mean age 21 ± 2 years) were included. Another cohort of 27 eyes (27 healthy control subjects matched with age and sex) was also recruited. All patients underwent multimodal imaging evaluation using structural optical coherence tomography (OCT), OCT-angiography (OCT-A), dynamic vessel analyzer (DVA) and microperimetry. No significant differences were disclosed comparing diabetics and controls for visual acuity, central macular thickness, and subfoveal choroidal thickness. On retinal nerve fiber layer and ganglion cell complex thickness, no significant differences were disclosed comparing each 3-mm-diameter macular and peripapillary subfield between two groups. Using OCT-A, deep capillary plexus perfusion density (PD) of diabetics was significantly lower compared to control group, whereas PD of other retinal/choriocapillaris plexuses and foveal avascular zone area did not show any significant difference. Using DVA, diabetic eyes revealed a significantly decreased vessel response to flicker light in comparison to controls. No differences were disclosed using microperimetry analysis. Taken together, these results suggest that vascular alterations could be the first detectable retinal change in the development of DR.

Natural History of Treatment-Naïve Quiescent Choroidal Neovascularization in Age-Related Macular Degeneration Using OCT Angiography

PURPOSE

To describe the evolution of treatment-naïve quiescent choroidal neovascularizations (CNVs) in age-related macular degeneration (AMD) by means of OCT angiography (OCTA).

DESIGN

Prospective, observational, consecutive case series.

PARTICIPANTS

Fifteen eyes (7 right eyes and 8 left eyes) of 14 patients (8 women and 6 men) fulfilled the criteria of quiescent CNV in AMD among an overall pool of 950 neovascular AMD patients.

METHODS

Consecutive patients with treatment-naïve quiescent CNV seeking treatment at 2 tertiary referral centers were followed up longitudinally for 1 year after diagnosis. The study included 3 visits at different time points. Each visit included measurement of best-corrected visual acuity, dilated fundus biomicroscopy, structural OCT, and OCTA. At baseline, fluorescein angiography and indocyanine green angiography also were performed to confirm diagnosis. Qualitative and quantitative analysis were assessed during a 12-month follow-up period.

MAIN OUTCOME MEASURES

Qualitative and quantitative assessment of OCTA images and evaluation of the rate of clinical activation.

RESULTS

Fifteen eyes of 14 patients were included in the analysis. Fourteen of 15 CNVs remained quiescent, and the rate of clinical activation was 6.6%. Qualitative analysis disclosed that the CNV core was visible in 2 of 14 eyes at baseline and in 3 of 14 eyes at 6 and 12 months; the CNV margin was well defined in 10 of 14 eyes and the CNV location was foveal involving in 8 of 14 eyes at all time points; CNV growth was displayed in 3 of 14 eyes at 6 months and in 10 of 14 eyes at 12 months compared with baseline images. Quantitative analysis revealed that despite an increase in CNV area (P = 0.039), CNV vessel density did not change (P = 0.731) in quiescent CNVs during follow-up.

CONCLUSIONS

We demonstrated biological activity of quiescent CNV by showing lesion growth over 12 months. Biological activity was not paralleled by clinical activity in most cases because of absence of exudation development over time, possibly because of unchanged CNV vessel density despite growth.

Choriocapillaris flow impairment could predict the enlargement of geographic atrophy lesion

AIM

To analyse the choriocapillaris (CC) flow status in the area that subsequently showed geographic atrophy (GA) expansion secondary to age-related macular degeneration (AMD) during 1-year follow-up, matching optical coherence tomography angiography (OCT-A) and fundus autofluorescence (FAF).

METHODS

In this prospective longitudinal observational study, 30 eyes of 20 consecutive patients with GA secondary to AMD (mean age 75.5±7.4 years) were included. All patients underwent OCT-A and FAF at baseline and 1-year follow-up. Main outcome measures included analysis of perfusion density (PD) in the 'area surrounding GA margin' (between the GA border and 500 µm distance) in comparison with the 'control area' (area outside the 500 µm line), and of the 'expansion area' (area that subsequently developed GA expansion during 1-year follow-up).

RESULTS

During the 1-year follow-up, visual acuity significantly decreased from 0.34±0.38 Logarithm of the Minimum Angle of Resolution (LogMAR) to 0.39±0.40 LogMAR (p<0.001), and mean GA area increased from 6.82±5.47 mm² to 8.76±6.28 mm² (p<0.001). CC PD of the area surrounding the GA margin revealed a significant flow impairment compared with control area (PD 0.679±0.076 and 0.734±0.057, respectively (p<0.001)). Furthermore, the PD of the expansion area showed a greater CC flow impairment in comparison to the remaining area surrounding GA margin (p<0.001).

CONCLUSIONS

We reported a greater CC impairment in the area that subsequently developed GA expansion, suggesting that the CC flow impairment could predict the enlargement of GA lesion. The CC impairment could be considered as a new a risk factor for GA progression and a biomarker to be measured to determine efficacy of new interventions aiming to slow progression of GA.

Response of central serous chorioretinopathy evaluated by multimodal retinal imaging

PurposeTo identify predictive biomarkers of treatment outcomes by multimodal retinal imaging in patients affected by central serous chorioretinopathy (CSC).Patients and methodsIn this interventional non-randomized clinical study, 27 treatment-naive CSC patients were prospectively enrolled and treated with oral eplerenone for 5-13 weeks. Primary outcomes included presence of pathological findings on indocyaine green angiography (ICGA), structural optical coherence tomography (OCT) and OCT-angiography (OCT-A) at baseline associated with different response to the treatment.ResultsA total of 29 eyes of 27 patients (2 females, 25 males) met the inclusion criteria and were included in the study (mean age was 45±7 years). Mean CSC duration at baseline was 13.5±4.4 weeks. After a mean of 10.5 weeks of treatment, mean central macular thickness significantly reduced (P<0.001), and mean best-corrected visual acuity improved (P<0.001). Seventeen eyes (61%) demonstrated total reabsorption of subretinal fluid on structural OCT, five eyes (18%) presented a partial response to eplerenone therapy and six eyes (21%) showed no response. The complete response to the treatment was associated with absence of CNV at OCT-A and the presence of hotspot at ICGA (P<0.001 and P=0.002, respectively). None of eight eyes with CNV in OCT-A imaging had a complete response to eplerenone and none of three eyes without hotspot at ICGA showed a complete response to the treatment.ConclusionsMultimodal retinal imaging allowed us to propose predictive biomarkers (ie, absence of CNV on OCT-A and presence of hotspot on ICGA) for treatment outcomes.

Retinal microcirculation abnormalities in patients with systemic sclerosis: an explorative optical coherence tomography angiography study

OBJECTIVES

To investigate subclinical or clinical abnormalities in retinal and choroidal vascular plexuses in patients with systemic sclerosis (SSc) by means of optical coherence tomography angiography (OCT-A).

METHODS

A total of 20 consecutive SSc patients were recruited and compared to 20 healthy subjects. Quantitative analysis of vessel density (VD), choriocapillaris plexus flow index (CCP-FI) and choroidal vascularity index were performed on OCT-A images in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris for all patients. Images were further reviewed by two independent readers for the assessment of qualitative abnormalities, including tortuosity, rarefaction areas, megacapillaries and macular-foveal capillaries (MFC).

RESULTS

The DCP-VD in the whole scan and in parafoveal, superior, inferior, nasal and temporal regions was significantly lower in the SSc group. The CC-FI was significantly higher in SSc patients. When comparing SSc patients with and without digital ulcers (DUs), significantly reduced SCP-VD was demonstrated in the whole, parafoveal, superior, inferior, temporal and nasal regions. No difference in any of the OCT-A parameters was observed when comparing patients with or without interstitial lung disease (ILD). Qualitative analysis of OCT-A revealed at least one abnormality in 95% of patients.

CONCLUSIONS

We showed the ability of OCT-A to disclose early ocular vascular abnormalities in patients with SSc. Our results may represent a hypothesis-generating basis for exploring the potential role of OCT-A in diagnosis, monitoring and prognosis stratification in SSc.

Umbilical Cord Blood and Serum for the Treatment of Ocular Diseases: A Comprehensive Review

Several blood derivatives have been proposed for the treatment of various ocular diseases that affect either the anterior or the posterior segment of the eye. Blood sources may range from the patient’s own peripheral blood (autologous) to donor tissues, mainly allogeneic peripheral blood and umbilical cord blood (UCB). The utilization of the latter permits the collection of a large amount of serum all at once, and is characterized by therapeutic feasibility in patients with a poor general condition or anemia and blood dyscrasia. Products derived from UCB have two potential uses. First, serum in the form of eye drops can be applied topically onto the ocular surface to efficiently treat anterior segment disorders such as dry eye syndrome or corneal epithelial defects with different etiologies. The rationale for and efficacy of this application derive from the high concentrations of biologically active components and growth factors in UCB, which can nourish the ocular surface. Second, UCB is a source of stem cells, which are used in the field of regenerative medicine because they differentiate into various mature cells, including corneal and retinal cells. Therefore, UCB-derived stem cells have been proposed as a replacement therapy for the treatment of retinal and optic nerve diseases, given that current standard treatments often fail. The present review explores the clinical results that have been obtained using UCB-derived products in the field of ophthalmology, as well as the current limitations of those products in this field. Furthermore, given the promising development of UCB-based therapies, possible future directions in this area are discussed.

Early response to the treatment of choroidal neovascularization complicating central serous chorioretinopathy: a OCT-angiography study

PURPOSE

To analyze the quantitative and qualitative early changes of choroidal neovascularization (CNV) associated with chronic central serous chorioretinopathy (CSC) after treatment using optical coherence tomography-angiography (OCT-A).

METHODS

Charts of consecutive patients with diagnosis of chronic CSC complicated by CNV were retrospectively reviewed. Included patients were divided in photodynamic therapy (PDT) or aflibercept group on the basis of the treatment received (half-fluence PDT or aflibercept 2.0 mg/0.05 ml intravitreal injection). Main outcome measures included the changes between baseline and 1-month follow-up in CNV vessel density (VD) and area on OCT-A images after thresholding and binarization.

RESULTS

A total of 30 eyes of 26 Caucasian patients were included: 17 eyes of 15 patients in PDT group (mean age 53 ± 11 years) and 13 eyes of 11 patients in aflibercept group (mean age 58 ± 8 years [p = 0.196]). In both PDT and aflibercept groups, best-corrected visual acuity improved at 1 month, and central macular thickness and subretinal fluid significantly decreased. VD did not change after the treatment in both groups (p = 0.502 and p = 0.086) although CNV area decreased significantly (from 0.586 ± 0.449 mm² to 0.553 ± 0.453 mm² [0.041]) in the PDT group, and nonsignificantly (from 0.767 ± 0.466 mm² to 0.733 ± 0.472 mm² [p = 0.095]) in the aflibercept group. The same results were confirmed in the subanalysis of the 18 treatment-naïve eyes.

CONCLUSIONS

We demonstrated that, despite all patients showed a favorable clinical response, VD of CNVs complicating chronic CSC did not change after treatment. These findings support the idea that arteriogenesis is the main driving force of CNV in pachychoroid-related macular disorders.

Optical Coherence Tomography Angiography in the Evaluation of Geographic Atrophy Area Extension

Purpose

To investigate the application of optical coherence tomography angiography (OCT-A) in evaluation of geographic atrophy (GA) secondary to age-related macular degeneration (AMD).

Methods

Patients with GA were prospectively enrolled and studied with blue fundus autofluorescence (FAF), en face structural OCT, and OCT-A. OCT-A images were acquired using a slab of whole choroid, whereas en face structural OCT images were obtained at the ellipsoid zone (EZ), at the choroidal (CH) level, and at the scleral (SC) level. Three readers independently measured the GA extension areas and evaluated the foveal sparing in each examination. Intraobserver/interobserver agreements and agreement between each couple of imaging techniques were assessed.

Results

A total of 47 eyes (26 patients, mean age 76 ± 7 years) with GA (mean area using FAF: 8.77 ± 5.00 mm2) were included. Intraobserver and interobserver agreement was excellent for all imaging techniques (intraclass correlation coefficient [ICC] > 0.985), even if en face EZ structural OCT revealed the poorest quality agreement limits. Considering the analysis between each couple of imaging techniques, ICC was excellent between OCT-A compared with FAF (ICC: 0.995), followed by en face structural OCT at CH level (ICC: 0.992), at SC level (ICC: 0.986), and at EZ level (ICC: 0.973). No differences were detected between multifocal and monofocal GA lesions. Considering the evaluation of foveal involvement, lower agreements were disclosed between FAF and all other imaging techniques.

Conclusions

OCT-A is a reliable technique for easily visualizing and quantifying GA with the advantages, compared to current imaging techniques, of offering together both structural and blood flow information regarding retinal and choroidal layers and excluding choroidal neovascularization.

Effects of calcium and vitamin supplementation on colon cell proliferation in colorectal cancer

Calcium and antioxidant vitamins, such as A, C, and E, have been shown to reduce colorectal epithelial proliferation and thereby to act as possible chemoprotective agents in colorectal cancer. We investigated the effects of an intervention with calcium and vitamins on cell proliferation in the colonic mucosa of patients operated on for colorectal cancer. Patients with resected colorectal cancer Dukes' stage B-C were randomized to receive daily 30,000 IU of axerophthol palmitate (vitamin A) plus 1 g ascorbic acid (vitamin C) plus 70 mg of dl-alpha-tocopherol acetate (vitamin E) and 2 g natural calcium daily or indistinguishable placebo for 6 months. At the time of surgery and after 6 and 12 months of treatment, cell kinetics of normal colonic mucosa were assessed by using proliferating cell nuclear antigen (PCNA). Ninety patients were enrolled and 77 were assessable: 34 in the treatment group and 43 in the placebo group. A significant reduction of mean total PCNA labeling index (PCNALI) was evident in both groups after 6 months (vitamins/calcium, from 16.11 +/- 2.43 to 10.71 +/- 2.81; placebo, from 17.30 +/- 2.63 to 12.53 +/- 3.40). The difference in the percentage of reduction of mean PCNALI between baseline and after 6 months was not statistically significant in the treatment and placebo groups: 34% and 28%, respectively. A second control, 6 months after discontinuation of vitamin and calcium supplementation, showed a further decrease of mean total PCNALI in both groups, but this was not statistically significant. Our randomized trial showed that calcium and vitamin supplementation does not reduce cell kinetics of colon epithelium. Furthermore, this study suggests the need for extreme caution in the interpretation and publication of studies on chemoprotectants in colon cancer without a control group.

Intravitreal injections during COVID-19 outbreak: Real-world experience from an Italian tertiary referral center

We report our experience during COVID-19 outbreak for intravitreal injections in patients with maculopathy. We proposed a treatment priority levels and timings; the "High" priority level includes all monocular patients; the "Moderate" is assigned to all patients with an active macular neovascularization; the patients affected by diabetic macular edema or retinal vein occlusion belong to the "Low" class. This organization allowed us to treat the most urgent patients although the injections performed had a 91.7% drop compared to the same period of 2019.

Optical coherence tomography angiography in pseudophakic cystoid macular oedema compared to diabetic macular oedema: qualitative and quantitative evaluation of retinal vasculature

AIMS

To describe optical coherence tomography angiography (OCT-A) abnormalities of patients with pseudophakic cystoid macular oedema (PCMO) before and after pharmacological resolution, compared with diabetic macular oedema (DMO) and normal eyes.

METHODS

In this retrospective, observational study, 44 eyes (30 patients) were included: 15 eyes (15 patients) affected by PCMO; 14 healthy fellow eyes used as negative control group; 15 eyes (15 age-matched and sex-matched patients) with DMO used as positive control group. All patients underwent a complete ophthalmological examination at baseline, including OCT-A scans of the macula through AngioPlex CIRRUS-5000 (Carl Zeiss Meditec, Dublin, USA). Patients with PCMO and DMO were re-evaluated after the pharmacological resolution of cystoid macular oedema (CMO).

RESULTS

Disruption of parafoveal capillary arcade and cystoid spaces in deep capillary plexus (DCP) were frequent in patients with PCMO and DMO (73% and 100%, 87% and 100%). Capillary abnormalities and non-perfusion greyish areas in DCP were more frequent in DMO (P<0.001 and P=0.014). Patients with PCMO showed a larger foveal avascular zone area in DCP at baseline (P<0.001), which significantly reduced after treatment (P=0.001). Vessel density of full-thickness retina and DCP was reduced in patients with PCMO (P=0.022 and P=0.001), and no changes were observed after treatment. Interestingly, DCP appeared less represented in patients with DMO than PCMO subjects (P=0.001).

CONCLUSIONS

Patients with PCMO have an impairment of mainly DCP, partially reversible after treatment. Furthermore, we disclosed that different alterations of the retinal vasculature characterise CMO derived from two different diseases, namely PCMO and DMO, and this could be due to their distinct pathophysiology.

Intravitreal Dexamethasone Implant as a Sustained Release Drug Delivery Device for the Treatment of Ocular Diseases: A Comprehensive Review of the Literature

Drug delivery into the vitreous chamber remains a great challenge in the pharmaceutical industry due to the complex anatomy and physiology of the eye. Intravitreal injection is the mainstream route of drug administration to the posterior segment of the eye. The purpose of this review is to assess the current literature about the widening use of the intravitreal 0.7 mg dexamethasone (Dex) implant, and to provide a comprehensive collection of all the ocular disorders that benefit from Dex administration. Although anti-vascular endothelial growth-factors (VEGFs) have been largely indicated as a first-choice level, the Dex implant represents an important treatment option, especially in selected cases, such as vitrectomized eyes or patients in whom anti-VEGF failed or are contraindicated. In this article, the safety profile as well as the list of the possible complications related to intravitreal Dex injection are also discussed.