Fluorescence lifetime distribution in phakic and pseudophakic healthy eyes.

PURPOSE To investigate the influence of the lens status and to describe fundus autofluorescence lifetimes (FLT) in a large cohort of healthy eyes across a wide age range. MATERIALS AND METHODS FLT data were acquired from healthy phakic and pseudophakic eyes using fluorescence lifetime imaging ophthalmoscopy (FLIO). Retinal autofluorescence was excited with a 473 nm laser and emitted autofluorescence was detected in a short and a long spectral channel (SSC: 498-560 nm; LSC: 560-720 nm). RESULTS 141 healthy eyes from 141 participants (56 ± 18 years) were included. The shortest mean FLTs were measured within the macular center, followed by the temporal inner and outer ETDRS (Early Treatment Diabetic Retinopathy Study) grid segments, and the remaining areas of the inner and the outer ETDRS ring. In phakic participants (81%), mean, short and long FLTs correlated with the age (SSC: r2 = 0.54; LSC: r2 = 0.7; both p<0.0001) with an increase of about 33 ps in the SSC resp. 28 ps in the LSC per decade. In pseudophakic subjects (19%), mean FLTs only correlated with age in the long spectral channel (r2 = 0.44; p = 0.0002) but not in the short spectral channel (r2 = 0.066; p = 0.2). CONCLUSIONS Fundus autofluorescence lifetimes are age dependent. FLTs in the SSC are more susceptible to lens opacities but less dependent on age changes, whereas FLTs in the LSC are largely independent of the lens status but display a higher degree of age dependency. STUDY REGISTRY ClinicalTrials.gov NCT01981148

Inner retinal layer change in glaucoma patients receiving anti-VEGF for neovascular age related macular degeneration.

PURPOSE The purpose was to evaluate the effects of long-term anti-VEGF treatment on the retinal nerve fiber layer (RNFL) and retinal ganglion cell layer (RGCL) thickness for patients with neovascular AMD and glaucoma. METHODS Medical records of respective patients who had received more than 15 anti-VEGF injections were reviewed. Initial and latest SD-OCT macular scans were segmented and changes of the RNFL and RGCL thickness at the four outer ETDRS quadrants were evaluated. Secondary outcome measures included changes of visual field parameters seen in automated perimetry. RESULTS Sixteen patients were included (mean age 78 ± 6 years). The mean total number of anti-VEGF injections was 39 ± 16. The mean treatment duration was 6.1 ± 2.1 years. The mean IOP decreased from 18 ± 5 mmHg at baseline to 15 ± 5 mmHg at the last visit (p = 0.026). The mean RNFL thickness volume of the outer ETDRS quadrants (0.98 ± 0.18 mm(3) to 0.97 ± 0.18 mm(3) p = 0.61) and its average thickness (37.9 ± 7.3 μm to 37.2 ± 7.4 μm, p = 0.6) did not significantly change. However, the average RGCL thickness decreased significantly from 0.86 ± 0.12 mm(3) to 0.79 ± 0.11 mm(3) (p = 0.01), and from 27.7 ± 4.2 to 25.9 ± 3.7 μm (p = 0.01). Number of injections correlated with the RGCL change (r2 = 0.36, p = 0.01). The mean sensitivity, mean defect and absolute scotomata did not significantly change with p-values of 0.28, 0.21 and 0.07, respectively. CONCLUSION Patients under long term treatment with anti-VEGF and concurrent glaucoma show significant decrease in macular RGLC volume. However, this decrease is comparable to reported RGCL decrease in patients under anti-VEGF treatment without underlying glaucoma and suggests that glaucoma patients may not be at a higher risk for losing macular RNFL and RGCL, at least if adequate control of intraocular pressure is maintained

Effect of Inhibition of Colony Stimulating Factor 1 Receptor on Choroidal Neovascularization in Mice.

Neovascular age-related macular degeneration is one of the leading causes of blindness. Microglia and macrophages play critical role in choroidal neovascularization (CNV) and may therefore be potential targets to modulate the disease course. This study evaluated the effect of the colony stimulating factor-1 receptor (CSF-1R) inhibitor PLX5622 on experimental laser-induced CNV. A 98% reduction of retinal microglia cells was observed in the retina one week after initiation of PLX5622 treatment, preventing accumulation of macrophages within the laser site and leading to a reduction of leukocytes within the choroid after CNV induction. Mice treated with PLX5622 had a significantly faster decrease of the CNV lesion size as revealed by in vivo imaging and immunohistochemistry from day 3 to day 14 compared to untreated mice. Several inflammatory modulators, such as CCL9, granulocyte-macrophage colony-stimulating factor, ssoluble tumor necrosis factor receptor-I, interleukin-1α, and matrix metallopeptidase-2 were elevated in the acute phase of the disease when microglia were ablated with PLX5622, whereas other cytokines (eg, interferon-γ, interleukin-4, and interleukin-10) were reduced. Our results suggest that CSF-1R inhibition may be a novel therapeutic target in patients with neovascular age-related macular degeneration

Enhanced-depth optical coherence tomography for imaging horizontal rectus muscles in Graves' orbitopathy.

PURPOSE Graves' orbitopathy (GO) is an extraocular eye disease with symptoms ranging from minor discomfort from dry eyes to strabismus and visual loss. One of the hallmarks of active GO is visible hyperemia at the insertion of the extraocular muscles. The aim of the present study was to evaluate the use of enhanced-depth imaging spectral domain anterior segment optical coherence tomography (EDI SD AS-OCT) for detecting pathological changes in horizontal recti muscles of patients with GO. METHODS Prospective cross sectional study of 27 eyes. Only women were included. EDI AS-OCT was used to measure the thickness of the tendons of the horizontal recti muscles in a predefined area in patients with GO and healthy controls. RESULTS EDI AS-OCT was able to image the tendons of the horizontal recti muscles in both healthy controls and patients suffering from GO. The mean thickness of the medial rectus muscle (MR) tendon was 256.4 μm [±17.13 μm standard deviation (SD)] in the GO group and, therefore, significantly thicker (p = 0.046) than in the healthy group which had a mean thickness of 214.7 μm (±5.516 μm SD). There was no significant difference in the mean thickness of the tendon of the lateral recti muscles (LRs) between these groups. CONCLUSION This is the first report showing that EDI AS-OCT is suitable to detect swelling at the insertion site of the MR muscle in GO. MR tendon thickness may be a useful parameter to monitor activity in these patients

AUTOMATED RETINAL LAYER SEGMENTATION AND THEIR THICKNESS PROFILES IN HEALTHY SUBJECTS: A Comparison of 55° Wide-field and Conventional 30° SD-OCT.

PURPOSE To assess whether retinal thickness measurements with a standard 30° spectral domain optical coherence tomography (SD-OCT) are comparable with wide-field 55° SD-OCT. METHODS Thirty-three healthy individuals were scanned using 55° as well as 30° SD-OCT according to a standardized protocol. Automated retinal layer segmentation of standard and wide-field SD-OCTs was assessed using customized software. RESULTS Both lenses showed a high correlation when analyzing total retinal thickness within the central, the inner, and the outer retinal ring (r = > 0.9). Automated thickness measurements with the 55° system were marginally higher compared with the 30° lens. The thickness of each separate retinal layer using automated segmentation showed excellent correlations within the inner and outer rings (range: r = 0.6-r = 0.9 for the inner ring and range: r = 0.9-r = 1.0 for the outer ring). CONCLUSION Fifty-five degree wide-field SD-OCT provides a good overview of the posterior pole and presents similar quantitative values as a standard 30° OCT lens. Therefore, thickness values are comparable when switching between these two lenses

Multimodal imaging of experimental choroidal neovascularization.

AIM To compare choroidal neovascularization (CNV) lesion measurements obtained by in vivo imaging modalities, with whole mount histological preparations stained with isolectin GS-IB4, using a murine laser-induced CNV model. METHODS B6N.Cg-Tg(Csf1r-EGFP)1Hume/J heterozygous adult mice were subjected to laser-induced CNV and were monitored by fluorescein angiography (FA), multicolor (MC) fundus imaging and optical coherence tomography angiography (OCTA) at day 14 after CNV induction. Choroidal-retinal pigment epithelium (RPE) whole mounts were prepared at the end of the experiment and were stained with isolectin GS-IB4. CNV areas were measured in all different imaging modalities at day 14 after CNV from three independent raters and were compared to choroidal-RPE whole mounts. Intraclass correlation coefficient (ICC) type 2 (2-way random model) and its 95% confidence intervals (CI) were calculated to measure the correlation between different raters' measurements. Spearman's rank correlation coefficient (Spearman's r) was calculated for the comparison between FA, MC and OCTA data and histology data. RESULTS FA (early and late) and MC correlates well with the CNV measurements ex vivo with FA having slightly better correlation than MC (FA early Spearman's r=0.7642, FA late Spearman's r=0.7097, and MC Spearman's r=0.7418), while the interobserver reliability was good for both techniques (FA early ICC=0.976, FA late ICC=0.964, and MC ICC=0.846). In contrast, OCTA showed a poor correlation with ex vivo measurements (Spearman's r=0.05716) and high variability between different raters (ICC=0.603). CONCLUSION This study suggests that FA and MC imaging could be used for the evaluation of CNV areas in vivo while caution must be taken and comparison studies should be performed when OCTA is employed as a CNV monitoring tool in small rodents

Comparison of two individualized treatment regimens with ranibizumab for diabetic macular edema.

PURPOSE To compare outcomes between an as-needed and a treat-and-extend regimen in managing diabetic macular edema with intravitreal ranibizumab. METHODS This was a retrospective, single-centre, comparative case series on 46 treatment naive patients with diabetic macular edema. Twenty-two patients were treated following an optical coherence tomography guided treat-and-extend protocol (OCTER), and 24 patients were treated according to a visual acuity guided pro re nata regimen (VAPRN) at a tertiarry referral centre. The main outcome measures were best-corrected visual acuity, central retinal thickness, and the number of ranibizumab injections, as well as visits after 12 months of treatment. RESULTS After 12 months, the mean gain in best-corrected visual acuity (± standard deviation) was 8.3 ± 6.7 versus 9.3 ± 8.9 letters in the VAPRN and OCTER group, respectively (p = 0.3). The mean decrease in central retinal thickness was 68.1 ± 88.0 μm in the VAPRN group and 117.6 ± 114.4 μm in the OCTER group (p = 0.2). The mean number of ranibizumab injections was significantly different between the VAPRN (5.9 ± 1.8) and the OCTER protocol (8.9 ± 2.0) (p < 0.001). CONCLUSION The visual acuity driven retreatment regimen resulted in a similar visual acuity outcome like optical coherence tomography guided retreatment for diabetic macular edema. Although the number of visits was similar in both groups, patients in the VAPRN group received significantly fewer intravitreal injections than patients in the OCTER group

Proliferative vitreoretinopathy: an update on the current and emerging treatment options.

Proliferative vitreoretinopathy (PVR) remains the main cause of failure in retinal detachment (RD) surgery and a demanding challenge for vitreoretinal surgeons. Despite the large improvements in surgical techniques and a better understanding of PVR pathogenesis in the last years, satisfactory anatomical and visual outcomes have not been provided yet. For this reason, several different adjunctive pharmacological agents have been investigated in combination with surgery. In this review, we analyze the current and emerging adjunctive treatment options for the management of PVR and we discuss their possible clinical application and beneficial role in this subgroup of patients

Challenges and insights in the exploration of the low abundance human ocular surface microbiome.

PURPOSE The low microbial abundance on the ocular surface results in challenges in the characterization of its microbiome. The purpose of this study was to reveal factors introducing bias in the pipeline from sample collection to data analysis of low-abundant microbiomes. METHODS Lower conjunctiva and lower lid swabs were collected from six participants using either standard cotton or flocked nylon swabs. Microbial DNA was isolated with two different kits (with or without prior host DNA depletion and mechanical lysis), followed by whole-metagenome shotgun sequencing with a high sequencing depth set at 60 million reads per sample. The relative microbial compositions were generated using the two different tools MetaPhlan3 and Kraken2. RESULTS The total amount of extracted DNA was increased by using nylon flocked swabs on the lower conjunctiva. In total, 269 microbial species were detected. The most abundant bacterial phyla were Actinobacteria, Firmicutes and Proteobacteria. Depending on the DNA extraction kit and tool used for profiling, the microbial composition and the relative abundance of viruses varied. CONCLUSION The microbial composition on the ocular surface is not dependent on the swab type, but on the DNA extraction method and profiling tool. These factors have to be considered in further studies about the ocular surface microbiome and other sparsely colonized microbiomes in order to improve data reproducibility. Understanding challenges and biases in the characterization of the ocular surface microbiome may set the basis for microbiome-altering interventions for treatment of ocular surface associated diseases