Vitreous anatomy and the vitreomacular correlation

Clinical factors and predictors for spontaneous separation of epiretinal membranes

PURPOSE

To investigate the clinical characteristics, imaging features, and predictive factors for spontaneous separation in patients with idiopathic or secondary ERM.

METHODS

The overall cohort was divided into two subgroups: idiopathic ERM (28 eyes, 56%) and secondary ERM (22 eyes, 44%). Electronic records and multimodal imaging were reviewed.

RESULTS

Among the 50 eyes included in this study, the self-separation of ERM occurred over a mean duration of 28.1 ± 25.3 months (median: 25.4 months). Compared with the secondary ERM group, the idiopathic group had a shorter interval to separation (idiopathic vs. secondary, 23.4 vs. 34.1 months, respectively; P = .01) and better vision at diagnosis (logMAR 0.094 vs. 0.224; P = .009) and after separation (logMAR 0.097 vs. 0.188; P = .01). Overall, in both subgroups, spontaneous ERM separation appeared to have been induced by posterior vitreous detachment (PVD) (P < .001). Multivariate analysis revealed that the self-separation interval (odds ratio [OR] 0.936) and IRF (OR 0.049) were significantly associated with complete ERM separation (all P < .05). Additionally, secondary ERM (OR 15.224) and lower initial best-corrected visual acuity (OR 267.589) were significantly associated with improvements in vision after self-separation (all P < .05).

CONCLUSION

The self-separation of ERM appears to be induced by PVD development in most eyes. Owing to the possibility of complete spontaneous separation, surgical membrane peeling may be delayed by up to 28 months in eyes without PVD, regardless of whether the cause is idiopathic or secondary. Patients with secondary ERM may experience favorable visual improvement after self-separation despite having poor vision at diagnosis and IRF on OCT.

KEY MESSAGES

What is known • An epiretinal membrane (ERM), the most prevalent retinal disease in adults, is less understood regarding clinical factors and the accurate mechanism of spontaneous separation. What is new • The separation of ERM appears to be induced by PVD development in most eyes. • Favorable vision outcomes were associated with secondary ERMs and lower initial visual acuity. • Complete ERM separation was associated with a shorter self-resolution interval and the absence of intraretinal fluid (IRF) in OCT imaging.

Etiologies and clinical characteristics of macular hole: An 8-year, single-center, retrospective study

To investigate the etiologies and clinical characteristics of full-thickness macular hole (FTMH) cases at Shanxi Eye Hospital in North China. Patients diagnosed with FTMH who underwent surgery from 2012 to 2020 were included, and the etiologies and clinical features of MH types were analyzed in an 8-year, cross-sectional, retrospective study. A total of 752 cases (776 eyes) were analyzed. The top 3 subtypes of MH were idiopathic (IMH, 64.4%), myopic (MMH, 21.1%) and traumatic (TMH, 3.7%) MH. Among these, there were significant differences in sex, age, and baseline best-corrected visual acuity (BCVA) distributions. Females predominated in the IMH and MMH groups, while males predominated in the TMH group. The IMH onset age was older than the MMH and TMH onset ages. Baseline BCVA in the IMH (Z = 8.9, P < .001) and the other group (Z = 4.0, P < .001) was significantly better than that in the MMH group. In the IMH group, females were younger, had a shorter axial length (AL), and had a worse baseline BCVA than males, while in the MMH group, there were no significant sex differences. Multivariate correlation analysis showed that a smaller hole diameter in IMH, no retinal detachment in MMH, and a younger age in TMH may result in better baseline BCVA. The most common MH etiologies were IMH, MMH and TMH, which contributed to differences in clinical features. Females predominated in the IMH and MMH groups, and the onset of MMH occurred 6.5 years earlier than the onset of IMH. Therefore, early fundus monitoring in females and high myopia patients is helpful for the early detection and treatment of MH.

Optical coherence tomography angiography in the diagnosis of ocular disease

Clinical imaging provided by optical coherence tomography (OCT) and its variant, OCT-angiography (OCT-A), has revolutionised eyecare practice. The imaging techniques allow for the identification and quantification of ocular structures, supporting the diagnosis and prognosis of eye disease. In this review, an overview of the usefulness of OCT-A imaging in the diagnosis and management of a range of ocular conditions is provided when used in isolation or in combination with other imaging modalities and measures of visual function (visual field results). OCT-A imaging has the capacity to identify and quantify ocular vasculature non-invasively, thereby assisting the clinician in the diagnosis or to determine the efficacy of intervention in ocular conditions impacting retinal vasculature. Thus, additional clinically useful information can be obtained in eye diseases involving conditions such as those impacting retinal vessel occlusion, in diabetic retinopathy, inherited retinal dystrophy, age-related macular degeneration, choroidal neovascularisation and optic nerve disorders. Through a clinical case series, various ocular conditions are reviewed, and the impact of OCT-A imaging is discussed. Although OCT-A imaging has great promise and is already used in clinical management, there is a lack of set standards to characterise altered vascular features in disease and consequently for prognostication, primarily due to a lack of large-scale clinical trials and variability in OCT-A algorithms when generating quantitative parameters.

Aqueous humor as eye lymph: A crossroad between venous and lymphatic system

Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.

Atavistic and vestigial anatomical structures in the head, neck, and spine: an overview

Organisms may retain nonfunctional anatomical features as a consequence of evolutionary natural selection. Resultant atavistic and vestigial anatomical structures have long been a source of perplexity. Atavism is when an ancestral trait reappears after loss through an evolutionary change in previous generations, whereas vestigial structures are remnants that are largely or entirely functionless relative to their original roles. While physicians are cognizant of their existence, atavistic and vestigial structures are rarely emphasized in anatomical curricula and can, therefore, be puzzling when discovered incidentally. In addition, the literature is replete with examples of the terms atavistic and vestigial being used interchangeably without careful distinction between them. We provide an overview of important atavistic and vestigial structures in the head, neck, and spine that can serve as a reference for anatomists and clinical neuroscientists. We review the literature on atavistic and vestigial anatomical structures of the head, neck, and spine that may be encountered in clinical practice. We define atavistic and vestigial structures and employ these definitions consistently when classifying anatomical structures. Pertinent anatomical structures are numerous and include human tails, plica semilunaris, the vomeronasal organ, levator claviculae, and external ear muscles, to name a few. Atavistic and vestigial structures are found throughout the head, neck, and spine. Some, such as human tails and branchial cysts may be clinically symptomatic. Literature reports indicate that their prevalence varies across populations. Knowledge of atavistic and vestigial anatomical structures can inform diagnoses, prevent misrecognition of variation for pathology, and guide clinical interventions.

An en face swept source optical coherence tomography study of the vitreous in eyes with anterior uveitis

PURPOSE

To analyse vitreous anatomy patients with anterior uveitis (AU) using swept source optical coherence tomography (SS-OCT).

METHODS

Patients with newly diagnosed AU and healthy participants were scanned using 16-mm SS-OCT B-scans and 12 × 12 mm cube centred at the fovea. Linear SS-OCT scans were evaluated to identify the premacular bursa (PB) above the macula and the Cloquet's canal above the optic disc. A dynamic evaluation of the 12 × 12 mm cube enabled en face measurement of the vertical and horizontal diameters of the PB and the presence/absence of communication between the PB and Cloquet's canal.

RESULTS

One hundred and thirty-five subjects were included in the study. Forty-five patients were healthy (mean age 33.47 years). En face measurements of the horizontal and vertical PB mean diameters were 5.2 mm and 4.7 mm. In 90 subjects with AU (mean age 30.10 years), the mean horizontal and vertical diameter of the PB were significantly larger (p < 0.01). Thirty-seven eyes with AU presented with cystoid macular oedema (CME). The mean diameters of the PB in this subgroup were significantly larger (p < 0.01). In 75% of the entire cohort (51% of eyes in the control group, 87% of eyes with AU and 100% of eyes with AU and CME), a channel connecting the PB and Cloquet's canal could be identified.

CONCLUSIONS

SS-OCT identification of a connecting channel between the PB and the Cloquet's canal suggests that inflammatory cytokines may drain from the anterior chamber through this system of channels, thus increasing the risk of CME.

Determining posterior vitreous structure by analysis of images obtained by AI-based 3D segmentation and ultrawidefield optical coherence tomography

AIMS

To determine the three-dimensional (3D) structure of the vitreous fluid including the posterior precortical vitreous pockets (PPVP), Cloquet's canal and cisterns in healthy subjects by AI-based segmentation of the vitreous of swept-source optical coherence tomography (OCT) images. In addition, to analyse the vitreous structures over a wide and deep area using ultrawidefield swept-source OCT (UWF-OCT).

METHODS

Ten eyes of six patients with the mean age was 40.7±8.4 years and the mean refractive error (spherical equivalent) was -3.275±2.2 diopters were examined.

RESULTS

In the UWF OCT images, the structure of the vitreous was observed in detail over 23 mm wide and 5 mm area. AI-guided analyses showed the complex 3D vitreous structures from any angle. Cisterns were observed to overlie the PPVP from the anterior. The morphology and locations of the cisterns varied among the subjects but tended to be similar in the two eyes of one individual. Cisterns joined the PPVPs superior to the macula to form a large trunk. This joined trunk was clearly seen in 3D images even in eyes whose trunk was not detected in the B scan OCT images. In some eyes, the vitreous had a complex appearance resembling an ant nest without large fluid-filled spaces.

CONCLUSIONS

A combination of UWF-OCT and 3D imaging is very helpful in visualising the complex structure of the vitreous. These technologies are powerful tools that can be used to clarify the normal evolution of the vitreous, pathological changes of vitreous and implications of vitreous changes in various vitreoretinal diseases.

Systemic oxidative stress biomarkers in patients with vitreomacular traction syndrome

PURPOSE

To evaluate whether the systemic oxidative stress biomarkers increased in patients with vitreomacular traction syndrome (VMT).

METHODS

This study compared 25 patients diagnosed with VMT with 20 healthy controls. As a biomarker of systemic oxidative stress, malondialdehyde (MDA) was measured. Total oxidant status (TOS) and total antioxidant status (TAS) were measured to evaluate the systemic oxidant status.

RESULTS

Serum MDA values were significantly higher among the patients (p < 0.001). The ideal cut-off value for MDA was determined to be 22.1 µmol/L, with 80% sensitivity and 75% specificity. The between-group differences were not statistically significant for TOS or TAS (p = 0.326 and p = 0.698, respectively).

CONCLUSION

Increased MDA levels suggest that systemic oxidative stress may play a role in VMT.

Anti-inflammatory Effect of Curcumin, Homotaurine, and Vitamin D3 on Human Vitreous in Patients With Diabetic Retinopathy

Purpose: To determine the levels of pro-inflammatory cytokines and soluble mediators (TNF-α, IL6, IL2, and PDGF-AB) in 28 vitreous biopsies taken from patients with proliferative diabetic retinopathy (PDR) and treated with increasing doses of curcumin (0. 5 and 1 μM), with or without homotaurine (100 μM) and vitamin D3 (50 nM). Materials and Methods: ELISA tests were performed on the supernatants from 28 vitreous biopsies that were incubated with bioactive molecules at 37°C for 20 h. The concentration of the soluble mediators was calculated from a calibration curve and expressed in pg/mL. Shapiro-Wilk test was used to verify the normality of distribution of the residuals. Continuous variables among groups were compared using the General Linear Model (GLM). Homoscedasticity was verified using Levene and Brown-Forsythe tests. Post-hoc analysis was also performed with the Tukey test. A p ≤ 0.05 was considered statistically significant. Results: The post-hoc analysis revealed statistically detectable changes in the concentrations of TNF-α, IL2, and PDGF-AB in response to the treatment with curcumin, homotaurine, and vitamin D3. Specifically, the p-values for between group comparisons are as follows: TNF-α: (untreated vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.008, (curcumin 0.5 μM vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.0004, (curcumin 0.5 μM vs. curcumin 1 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.02, (curcumin 1 μM vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.025, and (homotaurine 100 μM + vitamin D3 50 nM vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.009; IL2: (untreated vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.0023, and (curcumin 0.5 μM vs. curcumin 0.5 μM+ homotaurine 100 μM + vitamin D3 50 nM) p = 0.0028; PDGF-AB: (untreated vs. curcumin 0.5 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.04, (untreated vs. curcumin 1 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.0006, (curcumin 0.5 μM vs. curcumin 1 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.006, and (homotaurine 100 μM + vitamin D3 50 nM vs. curcumin 1 μM + homotaurine 100 μM + vitamin D3 50 nM) p = 0.022. IL6 levels were not significantly affected by any treatment. Conclusions: Pro-inflammatory cytokines are associated with inflammation and angiogenesis, although there is a discrete variability in the doses of the mediators investigated among the different vitreous samples. Curcumin, homotaurine, and vitamin D3 individually have a slightly appreciable anti-inflammatory effect. However, when used in combination, these substances are able to modify the average levels of the soluble mediators of inflammation and retinal damage. Multi-target treatment may provide a therapeutic strategy for diabetic retinopathy in the future. Clinical Trial Registration : The trial was registered at clinical trials.gov as NCT04378972 on 06 May 2020 ("retrospectively registered") https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid = S0009UI8&selectaction = Edit&uid = U0003RKC&ts = 2&cx = dstm4o.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Incidence of posterior vitreous detachment after congenital cataract surgery: an ultrasound evaluation

BACKGROUND

To investigate the incidence of developing posterior vitreous detachment (PVD) in children after congenital cataract surgery.

METHODS

This is a prospective study which recruited 131 children with congenital cataracts who underwent cataract surgery between June 1, 2015, and September 1, 2018. The patients were divided into two groups depending on their post-operation phakic status (with or without IOL implantation). Infants aged from 6 to 12 months from two groups were analyzed as subgroups, respectively. B-scan ultrasonography was performed before the procedure and at 1, 3, 6, 9, and 12-month follow-ups, respectively, after the operation.

RESULTS

Of the 131 eyes included in the analyses, 74 were aphakic, and 57 were pseudophakic after surgery. The postoperative rate of PVD in all analyzed eyes was 6.9% (9 of 131 eyes). After 12 months, PVD was significantly more prevalent in the eyes that underwent cataract surgery with IOL implantation (10.5%, 6 of 57 eyes) compared to the eyes without IOL implantation (4.1%, 1 of 74 eyes, P < 0.05); however, the eyes in the aphakic group were significantly younger than the eyes in the pseudophakic group, while the mean axial length (AL) of the pseudophakic eyes (21.11 ± 2.07 mm) was significantly higher than that of the aphakic eyes (18.93 ± 1.86 mm) (P < 0.01). In patients between the ages of 6 and 12 months of age from the two groups, the AL of patients with IOL implantation continued to be significantly increased compared to the group without IOL implantation (20.44 ± 1.68 mm vs. 19.78 ± 1.52 mm, P < 0.01). At the follow-up appointments, two patients with PVD were observed among the 14 eyes that had undergone cataract surgery with IOL implantation, while one eye was observed to have developed PVD among the 15 eyes without IOL implantation.

CONCLUSIONS

PVD occurs with greater frequency after congenital cataract surgery, particularly in eyes that have undergone IOL implantation. We suggest that PVD should be carefully monitored in children after congenital cataract surgery to avoid subsequent ocular pathologies such as retinal detachment. Future studies are needed to determine other potential risk factors that have not been as thoroughly explored, as opposed to better-known factors such as older age, longer axial length, and IOL implantation.

Characterisation of Glutathione Export from Human Donor Lenses

Purpose

To investigate whether human donor lenses are capable of exporting reduced glutathione.

Methods

Human lenses of varying ages were cultured in artificial aqueous humor for 1 hour under hypoxic conditions to mimic the physiologic environment and reduced glutathione (GSH) and oxidized glutathione (GSSG) levels measured in the media and in the lens.

Results

Human donor lenses released both GSH and GSSG into the media. Donor lenses cultured in the presence of acivicin, a γ-glutamyltranspeptidase inhibitor, exhibited a significant increase in GSSG levels (P < 0.05), indicating that GSSG undergoes degradation into its constituent amino acids. Screening of GSH/GSSG efflux transporters revealed Mrp1, Mrp4, and Mrp5 to be present at the transcript level, but only Mrp5 was expressed at the protein level. Blocking Mrp5 function with the Mrp inhibitor MK571 led to a significant decrease in GSSG efflux (P < 0.05), indicating that Mrp5 is likely to be involved in mediating GSSG efflux. Measurements of efflux from the anterior and posterior surface of the lens revealed that GSH and GSSG efflux occurs at both surfaces but predominantly at the anterior surface.

Conclusions

Human lenses export GSH and GSSG into the surrounding ocular humors, which can be recycled by the lens to maintain intracellular GSH homeostasis or used by neighboring tissues to maintain GSH levels.

Translational Relevance

Early removal of a clear lens, as occurs to treat myopia and presbyopia, would eliminate this GSH reservoir and reduce the supply of GSH to other tissues, which, over time, may have clinical implications for the progression of other ocular diseases associated with oxidative stress.

Microsurgical observation of the posterior vitreous in patients with vitreous hemorrhage caused by Terson syndrome

Purpose

To describe features characteristic of vitreous hemorrhage in patients with Terson syndrome observed through a microsurgical scope.

Methods

Between May 2015 and February 2019, 12 eyes of 10 patients with vitreous hemorrhage occurring after subarachnoid hemorrhage (SAH) underwent pars plana vitrectomy.

Results

During vitreous surgery, we found 10 of 12 eyes did not have posterior vitreous detachment (PVD). Furthermore, we observed in 9 of the 10 eyes without PVD (90.0%) that there was no hemorrhage in the posterior vitreous cavity at the posterior pole while we removed vitreous hemorrhage. We confirmed that this clean space could be the posterior precortical vitreous pocket (PPVP).

Conclusion and importance

Terson syndrome may have no hemorrhage in the PPVP regardless of the presence of severe vitreous hemorrhage. The cases presented in our study may suggest one of the mechanisms of Terson syndrome.

Characteristics of Posterior Precortical Vitreous Pockets and Cloquet’s Canal in Patients with Myopia by Optical Coherence Tomography

Purpose

To describe the morphological features of posterior precortical vitreous pockets (PPVP) and Cloquet's Canal in patients with myopia using swept-source optical coherence tomography (SS OCT).

Methods

A total of 96 eyes of 51 volunteers (range, 5-18 years) were enrolled in this study, and all individuals underwent OCT (Optovue Inc., Fremont, CA, USA) examinations. From the collected PPVPs images, the widths and heights of the PPVPs were measured, and connections between PPVPs and Cloquet's Canal were identified. The PPVPs widths and heights, width:height ratios and proportions of connections were compared among different age (5-8, 9-14, 15-18 years), axial length (AL; 21-23, 23-25, 25-29 mm) and myopia groups (hyperopia, low to moderate myopia, high myopia); the group data were analyzed to determine their relationship with myopia.

Results

PPVPs were identified in 89 of 96 eyes; 6 eyes were excluded for poor image quality. The PPVPs width was positively correlated with age, especially in the low to moderate myopia group (F = 7.715, P = 0.001). There was a significant difference in the PPVPs height between the refractive error groups in the 9 to 14 years group (F = 4.905, P = 0.005). The PPVPs width:height ratio was different among the refractive error groups in the 9 to 14 years group (F = 3.335, P = 0.041) and among the different age groups in the low to moderate myopia group (F = 6.077, P = 0.004). A total of 22 eyes (22.4%) were identified as having a connection between the PPVP and Cloquet's Canal. The connections began to increase with AL at 5 to 8 years (χ2 = 7.363, P = 0.025).

Conclusions

PPVPs existed in most myopia patients from 5 to 18 years old. PPVPs width was positively correlated with age, especially in the low to moderate myopia group. PPVPs height decreased in the 9 to 14 years group with myopia. An imbalance in the horizontal and vertical enlargement of PPVP was the main feature in the 9- to 14-year-old group with myopia. The connections between the PPVP and Cloquet's Canal were associated with AL extension in the 5- to 8-year-old group.

A Pilot Clinical Study of Intravitreal Injection of Artesunate for Ocular Neovascularization

Purpose: To evaluate the efficacy and primary safety of treatment with artesunate in reducing ocular neovascularization in humans. Methods: Five patients with corneal, iris, and retinal neovascularization and no light perception were treated with intravitreal injections of artesunate 80 μg. Visual acuity, anterior segment photography, fundus fluorescein angiography, and optical coherence tomography were used to evaluate efficacy, while intraocular pressure (IOP) and lens opacity degree were employed to evaluate safety. The primary endpoint was attenuation of neovascularization as determined at 24 weeks, with the last posttreatment follow-up at 52 weeks. Results: Corneal and iris neovascularization, which were secondary to fundus ischemic diseases and retinal neovascularization in all 5 patients, were attenuated after 1 or 2 injections by the 52-week follow-up. Retinal neovascularization was also attenuated, and papilledema was alleviated. The average IOP fell from 25.5 mmHg to 17.66 mmHg. Conclusions: This pilot study determined that intravitreal artesunate injection is efficacious for reducing corneal, iris, and retinal neovascularization. These results indicate that this drug may be a novel alternative to the currently popular antivascular endothelial growth factor drugs used to suppress ocular neovascularization and improve visual function.

Involvement of premacular mast cells in the pathogenesis of macular diseases

We previously reported on the elevated intravitreal activities of tryptase and chymase in association with idiopathic epiretinal membrane (ERM) and idiopathic macular hole (MH). In this present study, we investigated the potential intraocular production of these serine proteases, and measured and compared tryptase and chymase activities in the vitreous body and serum in ERM, MH, proliferative diabetic retinopathy (PDR), and rhegmatogenous retinal detachment (RRD) patients. In addition, nuclear staining with hematoxylin and eosin (H&E) and mast-cell staining with toluidine blue were performed on samples of the vitreous core and bursa premacularis (BPM) of MH. We also performed immunostaining on the above two regions of vitreous samples for MH with anti-tryptase antibody, anti-chymase antibody, anti-podoplanin antibody, anti-lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) antibody, and anti-fibroblast antibody. Moreover, we performed immunostaining with anti-tryptase antibody and anti-chymase antibody on ERMs collected intraoperatively. Tryptase activity in the vitreous body was significantly higher in ERM and MH than in PDR. However, no significant differences were observed in the tryptase activity in the serum among these four diseases. Chymase activity in the vitreous body was significantly higher in MH than in the other three diseases, yet chymase activity in the serum was below detection limit in any of the diseases. Nuclear staining with H&E revealed an abundance of nuclei in the BPM region, but few in the surrounding area. Mast-cell staining with toluidine blue revealed that the BPM showed metachromatic staining. In immunostaining with anti-fibroblasts antibody, anti-tryptase antibody, anti-chymase antibody, anti-podoplanin antibody, and anti-LYVE-1 antibody, the BPM stained more strongly than the vitreous core. Tryptase and chymase-positive cells were also observed in ERM. These findings revealed that the presence of mast cells in the BPM potentially represent the source of these serine proteases. Moreover, the BPM, as a lymphatic tissue, may play an important role in the pathogenesis of macular disease.

Absence of Posterior Vitreous Detachment Is a Risk Factor of Severe Bleb-Related Endophthalmitis

Purpose

Bleb-related endophthalmitis (BRE) after glaucoma surgery is an infection caused by bacteria in the avascular bleb gaining access into the eye. We report the clinical features and outcome of 10 consecutive eyes with severe BRE treated at our hospital.

Methods

Ten patients (10 eyes) with stage IIIb BRE after trabeculectomy diagnosed and treated at the Department of Ophthalmology, Tokyo Medical University, between April 2013 and May 2015, were studied. Patient background, type of glaucoma, interval from the first trabeculectomy, pretreatment bleb findings, causative microorganisms, surgical methods, status of posterior vitreous detachment (PVD), and postoperative visual acuity were examined.

Results

The 10 patients comprised 8 males and 2 females, with mean age of 70.6 years at BRE onset. The types of glaucoma were open-angle glaucoma in 7 patients, neovascular glaucoma in 2, and secondary glaucoma in 1. All eyes underwent trabeculectomy combined with mitomycin C prior to the development of BRE. The interval from the first glaucoma surgery to onset of endophthalmitis was 8.5 ± 4.1 years. Examination of the bleb revealed leakage of aqueous humor from the avascular bleb in all eyes. Bacteria were isolated from intraocular samples of 8 eyes; namely, Viridans streptococci in 5 eyes, Staphylococcus epidermidis in 1, Branhamella catarrhalis in 1, and coagulase-negative Staphylococci in 1. BRE was treated by vitrectomy in 9 eyes and enucleation in 1 eye. PVD was produced intentionally during vitrectomy in 6 eyes. Histopathological examination of the enucleated eye showed no PVD. Visual acuity improved by 3 lines or more in 6 patients, while decimal visual acuity remained lower than 0.1 in 4 patients.

Conclusion

BRE developed frequently in eyes with no PVD. The absence of PVD may be a risk factor of severe BRE.

Endoscopy-assisted vitrectomy in the anterior vitreous

Endoscopy-assisted ocular surgery is a relatively old technique that is increasingly being recognized for its application in cases of vitreoretinal disease. This technique is especially useful when both the vitreous and retina are difficult to access because of media opacity, a small pupil, or a microcornea. In this context, the anterior vitreous is often difficult to dissect because of its complex pathological changes. This article reviews the common anatomical features and pathologies that are observed in the anterior vitreous, as well as the applications and indications of endoscopy-assisted vitrectomy in the anterior vitreous.

Observation of neovascularization of the disc associated with proliferative diabetic retinopathy using OCT angiography

PURPOSE

To describe the relationship between the vitreous and the neovascularization of the disc (NVD) using swept source optical coherence tomography (SS-OCT) and OCT angiography (OCTA).

STUDY DESIGN

Retrospective.

METHODS

We examined 17 eyes of 11 consecutive patients diagnosed as NVD associated with proliferative diabetic retinopathy (PDR). The location of the NVD feeder or collector vessels were examined by using RTVue XR Avanti. To determine the condition of the posterior vitreous detachment (PVD) and the proliferative tissue of the NVD, we performed 12 mm horizontal and vertical scans through the disc using SS-OCT.

RESULTS

OCT images of all 17 cases indicated there was no PVD on the optic disc. OCTA showed that the locations of the newly formed vessels from the optic disc were overwhelmingly outside the physiological cupping (95%). No cases exhibited formation of neovascularization inside the physiological cupping. OCT images revealed all 17 eyes had proliferative tissues located under the posterior wall of the vitreous, with 12 out of 17 eyes exhibiting additional invasion of the proliferative tissue into the vitreous through the posterior wall. Epiretinal membrane or a thickened posterior wall of the vitreous was present in 10 out of the 17 eyes.

CONCLUSIONS

NVD associated with PDR arises from outside the physiological cupping and grows along the posterior wall of the vitreous. The absence of PVD on the optic disc is essential to the growth of NVD.

TOMOGRAPHIC RELATIONSHIPS BETWEEN RETINAL NEOVASCULARIZATION AND THE POSTERIOR VITREOUS IN PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To describe anatomical relationships of retinal neovascular complexes (NVCs) and the posterior vitreous in proliferative diabetic retinopathy using spectral domain optical coherence tomography.

METHODS

Cross-sectional study. Neovascular complexes were imaged using spectral domain optical coherence tomography in 51 eyes of 37 patients. The relationship of NVCs to the posterior vitreous cortex and posterior vitreous spaces, such as the premacular bursa, prevascular vitreous fissures, and perimacular cisterns, was analyzed.

RESULTS

In the 77 NVCs evaluated, 61 (79%) had grown along the outer surface of the posterior hyaloid face, and vitreoschisis was present in 37 (48%). The "wolf's jaw" configuration was present in 9% and resulted from NVC arising from the arcades and proliferating along the posterior hyaloid face. By contrast, NVCs that invaded the bursa originated from smaller venous tributaries more distant from the arcades. The premacular bursa and prevascular vitreous fissure/perimacular cistern were invaded infrequently, respectively, in 15% and 38% (P = 0.137).

CONCLUSION

Tomographic analysis of diabetic NVCs showed that most NVCs arise and grow along the posterior hyaloid face and that vitreoschisis is more prevalent than what has been found in ultrasound studies. The wolf's jaw configuration does not seem to result from the invasion of the bursa, as previously suggested.

Paravascular inner retinal abnormalities in healthy eyes

PURPOSE

To investigate the prevalence and characteristics of paravascular inner retinal abnormalities in healthy eyes.

MATERIALS AND METHODS

In this prospective observational case series, we included 178 healthy eyes (178 patients) with no ocular diseases. Eyes with co-existing ocular diseases, e.g., epiretinal membrane, glaucoma, or high myopia, were excluded from the current study. The posterior pole and paravascular areas of the temporal arcade vessels were comprehensively examined by dense radial scanning of optical coherence tomography (OCT) with the extended field imaging technique.

RESULTS

On fundus photography, no inner retinal abnormalities were detected along the temporal arcade vessels. On OCT sections, paravascular inner retinal abnormalities were seen in 77 (43.3%) eyes. In 71 (39.9%) eyes, inner retinal cystoid or fissure-like spaces that had no connection to the vitreous cavity were seen adjacent to the temporal arcade vessels. Most of these lesions were detected only on several consecutive OCT sections. In four (2.2%) eyes, inner retinal cleavages with openings to the vitreous cavity were seen adjacent to the temporal arcade vessels. These lesions were more frequently detected in the inferior hemisphere and along the major retinal veins. No eyes showed typical broad defects of the inner retinal tissue. There were no significant differences in age, gender, visual acuity, refractive error, or axial length between eyes with or without paravascular inner retinal abnormalities.

CONCLUSIONS

Paravascular cystoid or fissure-like spaces were frequently seen in the inner retina of healthy eyes. However, we detected no typical paravascular inner retinal defects in healthy eyes.

The link between morphology and complement in ocular disease

The complement system is a vital component of the immune-priveliged human eye that is always active at a low-grade level, preventing harmful intraocular injuries caused by accumulation of turnover products and controlling pathogens to preserve eye homeostasis and vision. The complement system is a double-edged sword that is essential for protection but may also become harmful and contribute to eye pathology. Here, we review the evidence for the involvement of complement system dysregulation in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica, highlighting the relationship between morphogical changes and complement system protein expression and regulation in these diseases. The potential benefits of complement inhibition in age-related macular degeneration, glaucoma, uveitis, and neuromyelitis optica are abundant, as are those of further research to improve our understanding of complement-mediated injury in these diseases.

Effect of vitreomacular separation on macular thickness determined by spectral-domain optical coherence tomography

PURPOSE

To determine the effects of vitreomacular separation on macular thickness.

METHODS

This was a retrospective, observational, cross-sectional study. Average foveal and central minimum thicknesses were measured by spectral-domain optical coherence tomography (SD-OCT) in 308 eyes of 308 healthy subjects (healthy group) and 298 normal fellow eyes of 298 patients with a unilateral macular hole (MH group). Multiple regression analyses were performed to determine the effects of various factors on the macular thickness.

RESULTS

The mean age of the healthy group was 67.3 ± 9.6 years (range 40-88 years) and that of the MH group was 67.8 ± 7.0 years (range 43-91). SD-OCT images showed that 149 eyes (48.4 %) in the healthy group and 174 eyes (58.4 %) in the MH group had a vitreomacular separation. In the healthy group, the central minimum thickness of eyes with a vitreomacular separation (196 µm) was significantly thinner than those without a vitreomacular separation (205 µm; P < 0.001). In the MH group, the average foveal thickness (234 µm) and the central minimum thickness (177 µm) in eyes with a vitreomacular separation were thinner than those without it (247 and 199 µm, respectively; both P < 0.001). Multiple regression analyses showed that a vitreomacular separation was significantly correlated with thinner central minimum thicknesses in both groups (P < 0.001) and also with the average foveal thickness in the MH group (P < 0.001).

CONCLUSIONS

A vitreomacular separation caused thinning of the central fovea in both the healthy eyes and the normal fellow eyes of unilateral MH patients; the extent of foveal thinning is greater in the MH group.