September 2016

Ocular neovascularization is a leading cause of blindness in proliferative retinopathy. Small non-coding RNAs (sncRNAs) play critical roles in both vascular and neuronal development of the retina through post-transcriptional regulation of target gene expression. To identify the function and therapeutic potential of sncRNAs in retinopathy, we assessed the expression profile of retinal sncRNAs in a mouse model of oxygen-induced retinopathy (OIR) with pathologic proliferation of neovessels. Approximately 2% of all analyzed sncRNAs were significantly altered in OIR retinas compared with normoxic controls. Twenty three microRNAs with substantial up- or down-regulation were identified, including miR-351, -762, -210, 145, -155, -129-5p, -150, -203, and -375, which were further analyzed for their potential target genes in angiogenic, hypoxic, and immune response-related pathways. In addition, nineteen small nucleolar RNAs also revealed differential expression in OIR retinas compared with control retinas. A decrease of overall microRNA expression in OIR retinas was consistent with reduced microRNA processing enzyme Dicer, and increased expression of Alu element in OIR. Together, our findings elucidated a group of differentially expressed sncRNAs in a murine model of proliferative retinopathy. These sncRNAs may exert critical post-transcriptional regulatory roles in regulating pathological neovascularization in eye diseases.

PURPOSE: To analyze the clinical and histopathologic features of 5 failed autologous cartilaginous grafts to the lower eyelids and to analyze the reasons for these failures. METHODS: In this retrospective case series, the data collected included patient ages, reasons for and duration of cartilaginous graft implants, sources of cartilaginous grafts, and clinical and histopathologic findings at time of graft removal using hematoxylin and eosin, elastic, Alcian blue, and Masson trichrome staining for analysis of tissue alterations. RESULTS: Five cartilaginous, posterior lamellar lower eyelid grafts were complicated by eyelid thickening or retraction, graft extrusion, and entropion. Histopathologic findings included segmentation of the original single implant, stripped of its perichondrium, due to "kerfing," sometimes with overlapping of the segments and scar formation between the segments. In place of the perichondrium that had been removed during the preparation the graft implants, a fibrous pseudoperichondrial capsule had formed. Pyknotic nuclei in varying degrees were typically found in the center of the grafts, despite a high degree of preservation of the extracellular matrix (collagenous, elastic, and proteoglycan components). No evidence of inflammation, cartilaginous vascularization, or necrosis was identified in any graft. CONCLUSION: Despite minimal reactive processes, kerfing (partial thickness cuts made in the graft to increase its pliancy) may be partially responsible for graft migration, deformation, and surgical failure. The consequences were graft fragmentation and overlapping of the multiple fragments. Graft migration can be exacerbated if a posterior lamellar graft is used to correct an anterior lamellar deficiency. Interference with the overall architectural integrity of the graft and its extracellular matrix appears to play no role in failure, despite removal of the perichondrium. Mild to moderate degrees of chondrocytic dropout in the absence of necrosis and inflammation are probably attributable to the thick and coarsely textured collagen of the fibrous pseudoperichondrial capsule that may impede diffusion of nutrients into the center of the graft.

Specific lineages of the commensal bacterium Enterococcus faecium belonging to CC17, especially ST412, have been isolated from patients in several hospitals worldwide and harbor antibiotic resistance genes and virulence factors. Here, we report a high-quality draft genome sequence and highlight features of E. faecium VRE16, a representative of this ST.

Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population in developed countries, and its prevalence will increase as the global incidence of diabetes grows exponentially. DR begins with an early nonproliferative stage in which retinal blood vessels and neurons degenerate as a consequence of chronic hyperglycemia, resulting in vasoregression and persistent retinal ischemia, metabolic disequilibrium, and inflammation. This is conducive to overcompensatory pathological neovascularization associated with advanced proliferative DR. Although DR is considered a microvascular complication, the retinal microvasculature is intimately associated with and governed by neurons and glia; neurodegeneration, neuroinflammation, and dysregulation of neurovascular cross talk are responsible in part for vascular abnormalities in both early nonproliferative DR and advanced proliferative DR. Neuronal activity directly regulates microvascular dilation and blood flow in the process of neurovascular coupling. Retinal neurons also secrete guidance cues in response to injury, ischemia, or metabolic stress that may either promote or suppress vascular outgrowth, either alleviating or exacerbating DR, contingent on the stage of disease and retinal microenvironment. Neurodegeneration, impaired neurovascular coupling, and dysregulation of neuronal guidance cues are key events in the pathogenesis of DR, and correcting these events may prevent or delay development of advanced DR. The review discusses the mechanisms of neurovascular cross talk and its dysregulation in DR, and their potential therapeutic implications.

PURPOSE: To describe the clinical and visual outcomes of juvenile idiopathic arthritis (JIA)-associated uveitis in adults and to examine risk factors for ongoing inflammation in adulthood. METHODS: Medical records were reviewed for patients with JIA-associated uveitis who were >16 years old at the final visit (the last visit prior to data collection). RESULTS: In total, 135 eyes of 77 patients (70 female, 7 male) were included. The mean age of patients at the final visit was 29.72 ± 11.27 years. The number of eyes with visual acuity of ≤20/50 and ≤20/200 at the final visit was 37 (28 %) and 20 (15 %), respectively; at least one ocular complication was present in 72 % of eyes. Band keratopathy was the most frequent complication (42 %), followed by cataract (25 %), posterior synechiae (22 %), maculopathy (22 %), ocular hypertension (13 %), and hypotony (5 %). At the final visit, patients who were >16 years of age at presentation to the Massachusetts Eye Research and Surgery Institution had more ocular complications and a greater degree of vision loss than patients who were ≤16 years of age. Ongoing inflammation at the final visit was noted in 40 patients (52 %). The presence of posterior synechiae, hypotony, cataract at presentation, and a history of cataract surgery prior to presentation were predictive of ongoing inflammation in adulthood in univariate analysis. The presence of hypotony and posterior synechiae at the initial visit were predictive factors in multivariate analysis. CONCLUSIONS: JIA-associated uveitis may be associated with ongoing inflammation, ocular complications, and severe visual impairment in adulthood. The presence of posterior synechiae and hypotony at the initial visit is predictive of ongoing inflammation.

PURPOSE: To summarize various topics and the cutting edge approaches to refine XFS pathogenesis that were discussed at the 21st annual Glaucoma Foundation Think Tank meeting in New York City, Sept. 19-20, 2014. METHODS: The highlights of three categories of talks on cutting edge research in the field were summarized. RESULTS: Exfoliation syndrome (XFS) is a systemic disorder with a substantial ocular burden, including high rates of cataract, cataract surgery complications, glaucoma and retinal vein occlusion. New information about XFS is akin to puzzle pieces that do not quite join together to reveal a clear picture regarding how exfoliation material (XFM) forms. CONCLUSION: Meeting participants concluded that it is unclear how the mild homocysteinemia seen in XFS might contribute to the disarrayed extracellular aggregates characteristic of this syndrome. Lysyl oxidase-like 1 (LOXL1) variants are unequivocally genetic risk factors for XFS but exactly how these variants contribute to the assembly of exfoliation material (XFM) remains unclear. Variants in a new genomic region, CACNA1A associated with XFS, may alter calcium concentrations at the cell surface and facilitate XFM formation but much more work is needed before we can place this new finding in proper context. It is hoped that various animal model and ex vivo systems will emerge that will allow for proper assembly of the puzzle pieces into a coherent picture of XFS pathogenesis. A clear understanding of XFS pathogenesis may lead to 'upstream solutions' to reduce the ocular morbidity produced by XFS.

Vascular endothelial cell growth factor A (VEGF) is a biologically and therapeutically important growth factor because it promotes angiogenesis in response to hypoxia, which underlies a wide variety of both physiological and pathological settings. We report here that both VEGF receptor 2 (VEGFR2)-positive and -negative cells depended on VEGF to endure hypoxia. VEGF enhanced the viability of platelet-derived growth factor receptor α (PDGFRα)-positive and VEGFR2-negative cells by enabling indirect activation of PDGFRα, thereby reducing the level of p53. We conclude that the breadth of VEGF's influence extends beyond VEGFR-positive cells and propose a plausible mechanistic explanation of this phenomenon.

PURPOSE: To report the occurrence of corneal ectasia (ECT) in patients with history of Stevens-Johnson syndrome (SJS), and to make the case for an association between these 2 diagnoses. We also report the impact of prosthetic replacement of the ocular surface ecosystem (PROSE) treatment on visual acuity (VA) in these patients. DESIGN: Retrospective cohort study. METHODS: A manufacturing database of PROSE patients from 2002 to 2014 at Boston Foundation for Sight (BFS), a single-center clinical practice, was reviewed to identify patients with diagnoses of both SJS and ECT. RESULTS: Nine patients were identified with diagnoses of both SJS and ECT. In each case, review of the medical record revealed that diagnosis of SJS preceded that of ECT. The prevalence of ECT in this population exceeded that in the general population (P < .0001). Videokeratography was available for 13 eyes in 7 patients; using Krumeich's classification of keratoconus, 3 eyes were found to be at stage 1, 3 at stage 2, 1 at stage 3, and 6 at stage 4. Sixteen of 18 eyes underwent PROSE treatment. Of these 16 eyes, initial median VA was 20/200 (range, count fingers to 20/20; logMAR 1.0). Median VA after PROSE customization was 20/30 (range, 20/60-20/15; logMAR 0.1761, P < .0025). CONCLUSIONS: ECT occurs at a higher-than-expected rate in patients with a history of SJS. PROSE treatment improves VA in these patients. The basis of the association between SJS and ECT is considered, as well as the role of plausible contributory factors such as corneal microtrauma and matrix metalloproteinases.

AIMS: To evaluate ocular disease characteristics and successful therapeutic regimens in patients with scleritis associated with relapsing polychondritis (RP). To compare these features with those seen in patients with scleritis associated with other systemic immune-mediated diseases (SIMD). METHODS: Electronic health records of 13 scleritis patients associated with RP were analysed and compared with those of 113 scleritis patients associated with other SIMD seen at two tertiary referral centres. RESULTS: Scleritis in patients with RP was often bilateral (92.3%), diffuse (76.9%), recurrent (84.6%), sometimes with decreased vision (46.2%), anterior uveitis (38.5%), peripheral keratitis (15.4%) and ocular hypertension (30.8%). Patients with scleritis associated with RP more often had bilateral scleritis (p=0.001), necrotising scleritis (23.1%; p=0.02), recurrences (p=0.001) and decreased vision (three of the six with legal blindness; p=0.012), as compared with patients who had scleritis associated with other SIMD. Nine patients (69.2%) had one or more SIMD other than RP, including systemic vasculitis (4) or other autoimmune disease (8); they antedated RP by 9 years (range 2-21 years). Successful therapy included cyclophosphamide (5), methotrexate (3), azathioprine (3), mycophenolate mofetil (2), infliximab (2) and adalimumab (1). CONCLUSIONS: Scleritis may be the first manifestation whose study leads to the diagnosis of RP. Scleritis associated with RP is more often bilateral, necrotising, recurrent and associated with decrease of vision than scleritis associated with other SIMD. About 69.2% of patients will have an additional SIMD disorder. Scleritis associated with RP most often will require immunomodulatory therapy. Occasionally, scleritis with RP may appear while using antitumor necrosis factor α agents.

PURPOSE: To compare microcatheter-assisted trabeculotomy with standard rigid probe trabeculotomy for the treatment of childhood glaucoma. METHODS: The early postoperative (12 months) results of microcatheter-assisted trabeculotomy (group 1) performed by single surgeon were retrospectively compared with those of rigid probe trabeculotomy (group 2) performed by the same surgeon in patients treated for childhood glaucoma. Success was defined as an intraocular pressure (IOP) <21 mm Hg with at least a 30% reduction from preoperative IOP with (qualified success) or without (complete success) the use of anti-glaucoma medication. RESULTS: A total of 43 eyes of 36 patients were included. Mean IOP in group 1 was significantly lower than that in group 2 at 6 months (17.0±5.1 vs 22.5±9.8; p=0.042), 9 months (16.3±5.0 vs 21.6±9.6; p=0.009) and 12 months (14.8±2.5 vs 19.0±7.1; p=0.049) postoperatively. The mean percentage reduction in IOP from preoperative to the last postoperative follow-up was greater in group 1 (47.3±17.7%) than in group 2 (34.2±21.9%) (p=0.036). group 1 demonstrated an 81.0% complete and 86.4% qualified success rate, exceeding the 51.6% complete (p=0.060) and 61.9% qualified (p=0.037) success rate of group 2. There were no long-term complications in either group, but choroidal detachment occurred in one eye in group 2. CONCLUSION: Microcatheter-assisted circumferential trabeculotomy is a more effective treatment and is as safe as traditional trabeculotomy with a rigid probe for primary congenital glaucoma in the early postoperative course. TRIAL REGISTRATION NUMBER: ChiCTR-OCC-15005789, Results.

PURPOSE: To evaluate the diagnostic performance of a 3-dimensional (3D) neuroretinal rim parameter, the minimum distance band (MDB), using optical coherence tomography (OCT) high-density volume scans for open-angle glaucoma. DESIGN: Reliability analysis. METHODS: setting: Institutional. STUDY POPULATION: Total of 163 patients (105 glaucoma and 58 healthy subjects). OBSERVATION PROCEDURES: One eye of each patient was included. MDB and retinal nerve fiber layer (RNFL) thickness values were determined for 4 quadrants and 4 sectors using a spectral-domain OCT device. MAIN OUTCOME MEASURES: Area under the receiver operating characteristic curve (AUROC) values, sensitivities, specificities, and positive and negative predictive values. RESULTS: The best AUROC values of 3D MDB thickness for glaucoma and early glaucoma were for the overall globe (0.969, 0.952), followed by the inferior quadrant (0.966, 0.949) and inferior-temporal sector (0.966, 0.944), and then followed by the superior-temporal sector (0.964, 0.932) and superior quadrant (0.962, 0.924). All 3D MDB thickness AUROC values were higher than those of 2D RNFL thickness. Pairwise comparisons showed that the diagnostic performance of the 3D MDB parameter was significantly better than 2D RNFL thickness only for the nasal quadrant and inferior-nasal and superior-nasal sectors (P = .023-.049). Combining 3D MDB with 2D RNFL parameters provided significantly better diagnostic performance (AUROC 0.984) than most single MDB parameters and all single RNFL parameters. CONCLUSIONS: Compared with the 2D RNFL thickness parameter, the 3D MDB neuroretinal rim thickness parameter had uniformly equal or better diagnostic performance for glaucoma in all regions and was significantly better in the nasal region.

PURPOSE: To report the outcomes of tocilizumab treatment for refractory ocular inflammatory diseases. METHODS: A retrospective case series of 17 patients (28 eyes) diagnosed with recalcitrant ocular inflammatory diseases including uveitis (10 cases), scleritis (six cases) and orbital pseudotumour (one case), who received tocilizumab between April 2010 and March 2015. All patients were initiated with treatment of 4 mg/kg or 8 mg/kg tocilizumab. The primary outcome was absence of inflammation and achievement of steroid sparing at 6 and 9 months. Secondary outcomes were change in visual acuity and major adverse effects of tocilizumab causing discontinuation of the treatment. RESULTS: Mean age at initiation of tocilizumab was 41 ± 16 years. Prior to tocilizumab treatment, all patients underwent unsuccessful conventional immunosuppressive therapy while 94% of patients (16/17) failed treatment with various biological agents. After tocilizumab administration, control of inflammation and steroid sparing were achieved in 63% and 71% of uveitis patients at 6 and 9 months, while 50% of scleritis patients achieved the primary outcome at 6 and 9 months. Mean duration of tocilizumab therapy was 12.6 ± 10.0 (range, 2-35) months. Three of four patients who had a follow-up of at least 18 (range, 18-35) months experienced quiescent inflammation for up to 32 months of tocilizumab use until last visit. Four patients (24%) discontinued tocilizumab due to serious side effects including neutropenia, unacceptable dizziness and nausea, severe angioedema and severe abdominal pain. CONCLUSION: Our series demonstrated moderate efficacy of tocilizumab in recalcitrant uveitis and scleritis. Serious adverse effects were not uncommon.

PURPOSE: To evaluate tonometric outcomes of patients with primary angle closure glaucoma (PACG) who have undergone trabeculectomy with mitomycin C (MMC) with and without concurrent phacoemulsification and to identify risk factors for postoperative failure. PATIENTS AND METHODS: Retrospective cohort study of 44 eyes of 33 phakic patients who underwent trabeculectomy with MMC with or without combined phacoemulsification for PACG. The primary endpoint was qualified tonometric success at 12 months according to predefined criteria. LogMAR visual acuity, number of glaucoma medications, and postoperative complications were also evaluated. Cox proportional hazard regression analysis was performed to identify potential risk factors for trabeculectomy failure. RESULTS: Mean intraocular pressure (IOP) decreased from 21.3±7.9 to 12.2±3.9 mm Hg at 12 months (P<0.001) in all patients. A significant reduction in mean number of glaucoma medications (P<0.001) was also seen. There was no change in logMAR visual acuity (P=0.39) after 12 months. There were no significant intergroup differences in mean IOP (P=0.42), number of glaucoma medications (P=0.85), or logMAR visual acuity (P=0.42) between the trabeculectomy versus combined surgery groups after 12 months. Increased age, greater baseline IOP, limbus-based conjunctival flaps, and MMC duration >1 minute were associated with decreased risk of surgical failure. Concurrent phacoemulsification at the time of trabeculectomy did not alter tonometric success or rate of complications. CONCLUSIONS: In phakic patients with PACG, trabeculectomy with MMC significantly reduces IOP and number of glaucoma medications at 12 months without change in visual acuity. However, success rates are modest when based on more demanding tonometric criteria.

Primary open angle glaucoma (POAG) is a complex disease and is one of the major leading causes of blindness worldwide. Genome-wide association studies have successfully identified several common variants associated with glaucoma; however, most of these variants only explain a small proportion of the genetic risk. Apart from the standard approach to identify main effects of variants across the genome, it is believed that gene-gene interactions can help elucidate part of the missing heritability by allowing for the test of interactions between genetic variants to mimic the complex nature of biology. To explain the etiology of glaucoma, we first performed a genome-wide association study (GWAS) on glaucoma case-control samples obtained from electronic medical records (EMR) to establish the utility of EMR data in detecting non-spurious and relevant associations; this analysis was aimed at confirming already known associations with glaucoma and validating the EMR derived glaucoma phenotype. Our findings from GWAS suggest consistent evidence of several known associations in POAG. We then performed an interaction analysis for variants found to be marginally associated with glaucoma (SNPs with main effect p-value <0.01) and observed interesting findings in the electronic MEdical Records and GEnomics Network (eMERGE) network dataset. Genes from the top epistatic interactions from eMERGE data (Likelihood Ratio Test i.e. LRT p-value <1e-05) were then tested for replication in the NEIGHBOR consortium dataset. To replicate our findings, we performed a gene-based SNP-SNP interaction analysis in NEIGHBOR and observed significant gene-gene interactions (p-value <0.001) among the top 17 gene-gene models identified in the discovery phase. Variants from gene-gene interaction analysis that we found to be associated with POAG explain 3.5% of additional genetic variance in eMERGE dataset above what is explained by the SNPs in genes that are replicated from previous GWAS studies (which was only 2.1% variance explained in eMERGE dataset); in the NEIGHBOR dataset, adding replicated SNPs from gene-gene interaction analysis explain 3.4% of total variance whereas GWAS SNPs alone explain only 2.8% of variance. Exploring gene-gene interactions may provide additional insights into many complex traits when explored in properly designed and powered association studies.

Glaucoma is an optic neuropathy that is characterized by the progressive degeneration of the optic nerve, leading to visual impairment. Glaucoma is the main cause of irreversible blindness worldwide, but typically remains asymptomatic until very severe. Open-angle glaucoma comprises the majority of cases in the United States and western Europe, of which, primary open-angle glaucoma (POAG) is the most common type. By contrast, in China and other Asian countries, angle-closure glaucoma is highly prevalent. These two types of glaucoma are characterized based on the anatomic configuration of the aqueous humour outflow pathway. The pathophysiology of POAG is not well understood, but it is an optic neuropathy that is thought to be associated with intraocular pressure (IOP)-related damage to the optic nerve head and resultant loss of retinal ganglion cells (RGCs). POAG is generally diagnosed during routine eye examination, which includes fundoscopic evaluation and visual field assessment (using perimetry). An increase in IOP, measured by tonometry, is not essential for diagnosis. Management of POAG includes topical drug therapies and surgery to reduce IOP, although new therapies targeting neuroprotection of RGCs and axonal regeneration are under development.

PurposeTo evaluate safety and efficacy of difluprednate 0.05% ophthalmic emulsion for treatment of postoperative inflammation after cataract surgery in pediatric patients.MethodsThis was a phase 3B, multicentre, randomized, double-masked, active-controlled study of patients aged 0-3 years who underwent uncomplicated cataract surgery in one eye, with/without intraocular lens implantation. Patients were randomized to receive difluprednate 0.05% four times daily or prednisolone acetate 1% for 14 days post surgery, followed by tapering for 14 days. Safety included evaluation of adverse events. Primary efficacy was the proportion of patients with an anterior cell grade of 0 (no cells) at day 14; secondary efficacy was a global inflammation score.ResultsForty patients were randomized to each treatment group. Adverse drug reactions included corneal oedema (difluprednate 0.5%, n=1; prednisolone acetate 1%, n=0) and increased intraocular pressure or ocular hypertension (n=2/group). Mean intraocular pressure values during treatment were 2-3 mm Hg higher with difluprednate 0.05% compared with prednisolone acetate 1%; mean values were similar between groups by the first week after treatment cessation. At 2 weeks post surgery, the incidence of complete clearing of anterior chamber cells was similar between groups (difluprednate 0.05%, n=30 (78.9%); prednisolone acetate 1%, n=31 (77.5%). Compared with prednisolone acetate 1%, approximately twice as many difluprednate 0.05%-treated patients had a global inflammation assessment score indicating no inflammation on day 1 (n=12 (30.8%) vs n=7 (17.5%) and day 8 (n=18 (48.7%) vs n=10 (25.0%).ConclusionsDifluprednate 0.05% four times daily showed safety and efficacy profiles similar to prednisolone acetate 1% four times daily in children 0-3 years undergoing cataract surgery.

PURPOSE: The human orbit is an environment that is vulnerable to inflammation and edema in the setting of autoimmune thyroid disease. Our study investigated the tenet that orbital adipose tissue lacks lymphatic vessels and analyzed the clinicopathologic differences between patients with acute and chronic thyroid eye disease (TED). The underlying molecular mediators of blood and lymphatic vessel formation within the orbital fat also were evaluated. DESIGN: Retrospective cohort study. PARTICIPANTS: The study included fat specimens from 26 orbits of 15 patients with TED undergoing orbital decompression. Orbital fat specimens from patients without TED as well as cadaveric orbital fat served as controls. METHODS: Tissue specimens were processed as formalin-fixed, paraffin-embedded sections or frozen cryosections for immunohistochemistry. Total RNA was extracted and analyzed via quantitative (real-time) reverse-transcription polymerase chain reaction. Clinicopathologic correlation was made by determining the clinical activity score (CAS) of each patient with TED. MAIN OUTCOME MEASURES: Samples were examined for vascular and lymphatic markers including podoplanin, lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), and cluster of differentiation 31 (CD31) by immunohistochemistry, as well as for mRNA levels of vascular endothelial growth factor (VEGF), VEGF receptors, semaphorin 3F, neuropilin 1, neuropilin 2, podoplanin, and LYVE-1 by quantitative (real-time) reverse-transcription polymerase chain reaction. RESULTS: Clinicopathologic correlation revealed increased staining of CD31-positive blood vessels in patients with acute TED with a CAS more than 4, as well as rare staining of podoplanin-positive lymphatic vessels within acutely inflamed orbital fat tissue. Additionally, quantitative (real-time) reverse-transcription polymerase chain reaction analysis demonstrated increased expression of VEGF receptor (VEGFR) 2 as well as VEGF signaling molecules VEGF-A, VEGF-C, and VEGF-D. CONCLUSIONS: In acute TED, compared with chronic TED and control orbital fat, there is increased blood vessel density, suggesting neovascularization and rare lymphatic vessels suggestive of limited lymphangiogenesis. This proangiogenic and prolymphangiogenic microenvironment is likely the result of the increased expression of VEGFR-2, VEGF-A, VEGF-C, and VEGF-D. These findings imply that orbital edema in acute TED may be mediated, in part, by both the formation of new, immature blood vessels and the formation of lymphatic capillaries that are functionally incapable of draining interstitial fluid.

Histological studies from autopsy specimens have characterized hard exudates as a composition of lipid-laden macrophages or noncellular materials including lipid and proteinaceous substances (hyaline substances). However, the characteristics of hard exudates in living patients have not been examined due to insufficient resolution of existing equipment. In this study, we used adaptive optics scanning laser ophthalmoscopy (AO-SLO) to examine the characteristics of hard exudates in patients with retinal vascular diseases. High resolution imaging using AO-SLO enables morphological classification of retinal hard exudates into two types, which could not be distinguished either on fundus examination or by spectral domain optical coherence tomography (SD-OCT). One, termed a round type, consisted of an accumulation of spherical particles (average diameter of particles: 26.9 ± 4.4 μm). The other, termed an irregular type, comprised an irregularly shaped hyper-reflective deposition. The retinal thickness in regions with round hard exudates was significantly greater than the thickness in regions with irregular hard exudates (P = 0.01 →0.02). This differentiation of retinal hard exudates in patients by AO-SLO may help in understanding the pathogenesis and clinical prognosis of retinal vascular diseases.

PURPOSE: To evaluate crosslinking of cornea in vivo using green light activation of Rose Bengal (RGX) and assess potential damaging effects of the green light on retina and iris. METHODS: Corneas of Dutch belted rabbits were de-epithelialized, then stained with Rose Bengal and exposed to green light, or not further treated. Corneal stiffness was measured by uniaxial tensiometry. Re-epithelialization was assessed by fluorescein fluorescence. Keratocytes were counted on hematoxylin and eosin (H&E)-stained sections, and iris cell damage was assessed by lactate dehydrogenase staining. Thermal effects on the blood-retinal barrier (BRB) were assessed by fluorescein angiography and those on photoreceptors, retinal pigment epithelium (RPE), and choriocapillaris by light microscopy and transmission electron microscopy. RESULTS: RGX (10-min irradiation; 150 J/cm) increased corneal stiffness 1.9-fold on day 1 (1.25 ± 0.21 vs. 2.38 ± 0.59 N/mm; P = 0.036) and 2.8-fold compared with controls on day 28 (1.70 ± 0.74 vs. 4.95 ± 1.86 N/mm; P = 0.003). Keratocytes decreased only in the anterior stroma on day 1 (24.0 ± 3.0 vs. 3.67 ± 4.73, P = 0.003) and recovered by day 28 (37.7 ± 8.9 vs. 34.5 ± 2.4, P = 0.51). Iris cells were not thermally damaged. No evidence of BRB breakdown was detected on days 1 or 28. Retina from RGX-treated eyes seemed normal with RPE cells showing intact nuclei shielded apically by melanosomes, morphologically intact photoreceptor outer segments, normal outer nuclear layer thickness, and choriocapillaris containing intact erythrocytes. CONCLUSIONS: The substantial corneal stiffening produced by RGX together with the lack of significant effects on keratocytes and no evidence for retina or iris damage suggest that RGX-initiated corneal crosslinking may be a safe, rapid, and effective treatment.