Dynamic angle closure following pars plana vitrectomy with perfluoropropane gas.

Purpose: To report the clinical course of an aphakic patient who developed positional secondary angle closure glaucoma following pars plana vitrectomy (PPV) with perfluoropropane (C3F8) gas tamponade. Observations: A 23-year-old male presented due to a two-year history of vision loss in the left eye. Best-corrected visual acuity (BCVA) was 20/200 and intraocular pressure (IOP) was 12 mm Hg OS. Exam revealed iridodonesis and aphakia of both eyes, and a total RRD in the left eye. The patient underwent scleral buckle plus PPV with 15 % C3F8 gas and was instructed to maintain face-down positioning for 5 days. On post-operative day 1, IOP was 32 mm Hg and exam revealed significant diffuse corneal edema, a large epithelial defect, and 85 % C3F8 fill of the vitreous cavity. Patient was started on IOP-lowering drops but continued to have elevated IOP and corneal epithelial sloughing over the next 3 weeks. He was taken for a superficial keratectomy, but when placed supine under the microscope, a large new gas bubble was visualized overlying the pupil in a now shallow anterior chamber (AC) and IOP was 52 mm Hg. The patient was positioned back upright and the gas bubble migrated posteriorly out of the AC with return of IOP to 25 mm Hg. The dynamic nature of his IOP raised concerns for intermittent angle closure by C3F8 induced by supine positioning. Thus, a pars plana aspiration of the C3F8 gas was performed and resulted in normalization of the IOP. Conclusions and importance: Dynamic, positional secondary angle closure glaucoma can occur after vitrectomy with C3F8 in the setting of aphakia. This is the first report to capture C3F8 gas migration causing intermittent acute angle closure in real-time. Due to its intermittent nature however, the diagnosis may not be initially apparent at the slit lamp. Thus, we suggest this potential complication should be carefully monitored for and discussed when advising post-vitrectomy positioning in aphakic patients.

Absence of Gut Microbiota Is Associated with RPE/Choroid Transcriptomic Changes Related to Age-Related Macular Degeneration Pathobiology and Decreased Choroidal Neovascularization.

Studies have begun to reveal significant connections between the gut microbiome and various retinal diseases, including age-related macular degeneration (AMD). As critical supporting tissues of the retina, the retinal pigment epithelium (RPE) and underlying choroid play a critical role in retinal homeostasis and degeneration. However, the relationship between the microbiome and RPE/choroid remains poorly understood, particularly in animal models of AMD. In order to better elucidate this role, we performed high-throughput RNA sequencing of RPE/choroid tissue in germ-free (GF) and specific pathogen-free (SPF) mice. Furthermore, utilizing a specialized laser-induced choroidal neovascularization (CNV) model that we developed, we compared CNV size and inflammatory response between GF and SPF mice. After correction of raw data, 660 differentially expressed genes (DEGs) were identified, including those involved in angiogenesis regulation, scavenger and cytokine receptor activity, and inflammatory response-all of which have been implicated in AMD pathogenesis. Among lasered mice, the GF group showed significantly decreased CNV lesion size and microglial infiltration around CNV compared to the SPF group. Together, these findings provide evidence for a potential gut-RPE/choroidal axis as well as a correlation with neovascular features of AMD.

Computerized Texture Analysis of Optical Coherence Tomography Angiography of Choriocapillaris in Normal Eyes of Young and Healthy Subjects.

Computerized texture analysis uses higher-order mathematics to identify patterns beyond what the naked eye can recognize. We tested its feasibility in optical coherence tomography angiography imaging of choriocapillaris. Our objective was to determine sets of parameters that provide coherent and consistent output when applied to a homogeneous, healthy group of patients. This observational cross-sectional study involved 19 eyes of 10 young and healthy Caucasian subjects. En-face macular optical coherence tomography angiography of superficial choriocapillaris was obtained by the RTVue-XR Avanti system. Various algorithms were used to extract texture features. The mean and standard deviation were used to assess the distribution and dispersion of data points in each metric among eyes, which included: average gray level, gray level yielding 70% threshold and 30% threshold, balance, skewness, energy, entropy, contrast, edge mean gradient, root-mean-square variation, and first moment of power spectrum, which was compared between images, showing a highly concordant homology between all eyes of participants. We conclude that computerized texture analysis for en-face optical coherence tomography angiography images of choriocapillaris is feasible and provides values that are coherent and tightly distributed around the mean in a homogenous, healthy group of patients. Homology of blob size among subjects may represent a "repeat pattern" in signal density and thus a perfusion in the superficial choriocapillaris of healthy young individuals of the same ethnic background.

Gnotobiotic Operations and Assembly for Development of Germ-Free Animal Model of Laser-Induced Choroidal Neovascularization.

Purpose: Compelling new evidence reveals a close link between the gut microbiome and the pathogenesis of neovascular age-related macular degeneration (nAMD). Germ-free (GF) animal models are the current gold standard for studying host the microbe interactions in vivo; yet, no GF animal models of nAMD are available today. This protocol describes gnotobiotic operations and assembly for a laser-induced choroidal neovascularization (CNV) model in GF mice to study the gut microbiome in neovascular AMD. Methods: We developed a step-wise approach to performing retinal laser photocoagulation in GF C57BL/6J mice that were bred and maintained at the gnotobiotic facility. Following a strict sterility protocol, we administered laser photocoagulation via an Argon 532-nm laser attached to a customized slit-lamp delivery system. Sterility was confirmed by weekly fecal cultures and reverse transcriptase-polymerase chain reaction. Results: The experiment was repeated twice at different time points using seven mice (14 eyes). Stool cultures and RT-PCR remained negative for 14 days post-procedure in all mice. Lectin immunostaining performed on choroidal flatmounts confirmed the presence of CNV lesions 2 weeks after laser treatment. Conclusions: We established a GF mouse model of nAMD with detailed guidelines to deliver retinal laser in GF mice maintaining sterility after the laser procedure. Translational Relevance: To our knowledge, this is the first protocol that describes a GF murine model of laser-induced CNV. In addition to nAMD, this animal model can be used to investigate host-microbial interactions in other eye diseases with laser-induced mouse models such as glaucoma and retinal vein occlusion.

Herpes Simplex Virus 2 Meningoencephalitis-Associated Bilateral Optic Neuritis and Radiculitis.

The most common ocular complication of herpes simplex virus (HSV) is acute retinal necrosis. We present a rare case of a patient with HSV-2 meningoencephalitis that developed severe vision-threatening optic neuritis. The patient was treated with steroids and IVIG, which allowed a rapid improvement in her vision.

The microbiome and ophthalmic disease.

IMPACT STATEMENT: This review describes a growing body of research on relationships between the microbiome and eye disease. Several groups have investigated the microbiota of the ocular surface; dysregulation of this delicate ecosystem has been associated with a variety of pro-inflammatory states. Other research has explored the effects of the gastrointestinal microbiota on ophthalmic diseases. Characterizing the ways these microbiotas influence ophthalmic homeostasis and pathogenesis may lead to research on new techniques for managing ophthalmic disease.

Long-term Outcomes of Ocular Surface Stem Cell Allograft Transplantation.

PURPOSE: To investigate the long-term outcomes of ocular surface stem cell allograft transplantation (OSST) in patients with total limbal stem cell deficiency (LSCD) owing to various etiologies with a follow-up ≥ 5 years. DESIGN: Retrospective interventional cohort. METHODS: Setting: Single tertiary referral hospital. STUDY POPULATION: Patients who had (1) presence of total LSCD, (2) surgical treatment with at least 1 allograft OSST procedure, and (3) minimum follow-up ≥ 5 years after OSST. INTERVENTION: All patients underwent allograft OSST from March 1998 to June 2009. All patients received systemic immunosuppression. MAIN OUTCOME MEASURES: Ocular surface stability, best-corrected visual acuity (BCVA). RESULTS: A total of 165 eyes of 110 patients fulfilled the inclusion criteria with a mean follow-up period of 109.22 ± 35.7 months or approximately 9.1 years (range 5.2-17.7 years). Ocular surface stability was achieved in 72.7% (120/165) of eyes at last follow-up, while 15.2% (25/165) maintained an improved ocular surface and 12.1% (20/165) developed total surface failure. Additional OSST surgery was necessary in 30.9% (51/165 eyes) to maintain a stable ocular surface. There was ≥ 2 lines BCVA improvement in 62.1%, no change in 7.7%, and a worsened BCVA in 18.6% at last follow-up. CONCLUSIONS: With proper immunosuppression and repeat procedure in case of failure, allograft OSST can provide true long-term ocular surface stability and successful visual outcomes.

Late Acute Rejection After Allograft Limbal Stem Cell Transplantation: Evidence for Long-Term Donor Survival.

PURPOSE: To describe the clinical presentation and management of late (>3.0 years) acute graft rejection in keratolimbal allograft (KLAL) recipients. METHODS: This was a multicenter, retrospective observational case series. Six eyes of 6 patients with ocular surface transplant at a mean age of 36.2 years were seen at 3 tertiary referral centers for acute graft rejection between 2007 and 2013. Main outcome measures included strength of systemic immunosuppression (SI) at the time of rejection, time to rejection, and clinical presentation of rejection. RESULTS: Preoperative diagnoses included total limbal stem cell deficiency because of aniridia (n = 2) or chemical injury (n = 4). After an initially successful outcome, patients experienced late acute graft rejection at a mean time of 67.8 ± 24.1 months (range: 41-98) after KLAL while receiving suboptimal levels of SI because of medication taper (n = 5) or noncompliance (n = 1). Objective findings included an epithelial rejection line (n = 6), edema (n = 2), corneal epithelial irregularities (n = 2), and neovascularization (n = 1). Antirejection management consisted of topical corticosteroids (n = 6) and augmentation of SI therapy (n = 5). CONCLUSIONS: These cases of late acute graft rejection in KLAL patients support the notion that allodonor cells can persist over the long run and remain at risk for immunologic rejection. It further underscores the fact that long-term success with KLAL may require extension of SI beyond the first few years, albeit at lower levels individualized to each patient.

Superior Limbic Keratoconjunctivitis-like Inflammation in Patients with Chronic Graft-Versus-Host Disease.

PURPOSE: Describe the presentation and management of superior limbic keratoconjunctivitis (SLK)-like inflammation and secondary limbal stem cell dysfunction in the setting of ocular chronic graft-versus-host disease (cGVHD). METHODS: Retrospective observational case series in a multicenter clinical practice. Participants were 13 patients (26 eyes) with ocular cGVHD and SLK-like inflammation presenting to the University of Illinois at Chicago and BostonSight® between January 1, 2009 and July 1, 2013. MAIN OUTCOME MEASURES: 1) Reversal or worsening of SLK, and 2) development of limbal stem cell dysfunction. RESULTS: All eyes showed evidence of SLK-like inflammation and superior limbal stem cell dysfunction manifested by conjunctival injection and superior conjunctival and corneal staining. In addition to aggressive lubrication, management strategies for SLK included topical steroids (20/26), punctal occlusion (18/26), topical cyclosporine (24/26), autologous serum tears (12/26), therapeutic soft contact lens (13/26 eyes) and scleral lenses (4/26 eyes). SLK and limbal stem cell dysfunction were reversed in 23/26 eyes. Three eyes of two patients with long-standing disease demonstrated frank limbal stem cell deficiency (LSCD) and corneal pannus, with one patient requiring multiple reconstructive surgical procedures. CONCLUSIONS: SLK-like inflammation is an under-recognized condition in patients with severe dry eyes secondary to ocular cGVHD. Untreated SLK can potentially lead to permanent LSCD over time. Early recognition and management of SLK in ocular cGVHD can improve vision, reverse signs, and may prevent these long-term consequences.

Stability of limbal stem cell deficiency after mechanical and thermal injuries in mice.

We studied the reproducibility and stability of limbal stem cell deficiency (LSCD) in mice following controlled injuries to the corneal and limbal epithelia. In one method, corneal and limbal epithelia were entirely removed with a 0.5 mm metal burr. In the other, limbus to limbus epithelial removal with the burr was followed by thermal injury to the limbus. These two methods were compared with a previously published one. Unwounded corneas were used as control. The corneas were examined monthly for three months by slit lamp with fluorescein staining. Immunofluorescence staining for cytokeratin 12 and 8 on corneal wholemount and cross sections were performed to determine the phenotype of the epithelium. Mechanical shaving of the epithelium, with or without thermal injury, resulted in a reproducible state of LSCD marked by superficial neovascularization, reduce of keratin 12 expression and presence of goblet cells on the cornea. The phenotype was stable in 100% of the eyes up to at least three months. Thermal injury produced a more severe phenotype with more significant stromal opacification. These corneal injury models may be useful for studying the mechanisms leading to limbal stem cell deficiency.

Long-term management of severe ocular surface injury due to methamphetamine production accidents.

PURPOSE: The aim of this study was to report the clinical features and management of patients with ocular surface damage during methamphetamine production accidents. METHODS: This is a retrospective noncomparative interventional case series of 5 patients with methamphetamine production-related ocular injuries referred to the Cincinnati Eye Institute between 1999 and 2014. RESULTS: Four of 5 cases were white young men with severe bilateral ocular injury and extremely poor vision. All except 1 eye (9 of 10) were diagnosed with total or near-total ocular surface failure. Limbal stem cell transplantation was performed in 8 of 10 eyes. Keratolimbal allograft was followed by penetrating keratoplasty in 7 of 10 eyes. Ocular surface stability was achieved in 7 of 10 eyes after keratolimabl allograft. Postoperative visual acuity was better than 20/200 in 4 of 10 of eyes. Keratolimbal graft rejection occurred in 3 of 10 eyes; the rate of rejection of penetrating keratoplasty was also 3 out of 10 eyes. CONCLUSIONS: Methamphetamine-related accidents can lead to severe bilateral ocular injuries. Although stem cell transplantation procedure success is guarded in most of these patients because of severe conjunctival inflammation and accompanying ocular comorbidities, as well as personality issues, compliant patients can achieve good visual function with ocular surface transplantation and subsequent keratoplasty.

Cataract surgery in patients with ocular surface disease: An update in clinical diagnosis and treatment.

In this article we review essentials of diagnosis and management of ocular surface disease in patients who undergo cataract surgery. It is clearly shown that dry eye disease worsens following the cataract surgery in patients with prior history of ocular surface disease, Also new cases of dry eye might appear. Current strategies for the timely diagnosis and proper management of dry eye syndrome in the face of cataract surgery patients are mainly emphasized. To achieve the best outcome in cataract surgery, a healthy ocular surface is crucial. While ocular surface preparation is indispensable in patients with established ocular surface disease, it is also helpful in those with minimal signs or symptoms of surface disease. The current approach begins with early diagnosis and drastic management of ocular surface disease before cataract surgery using a stepwise regimen customized to each patient and disease severity. These measures are continued throughout and after the surgery.

The role of toll-like receptor 4 in corneal epithelial wound healing.

PURPOSE: We evaluated the role of Toll-like receptor 4 (TLR4) in corneal epithelial wound healing. METHODS: The expression of TLR4 during in vivo corneal epithelial wound healing was examined by immunostaining in mice. The expression and activation of TLR4 was studied in primary or telomerase-immortalized human corneal epithelial cells (HCEC). Scratch assay was performed to evaluate in vitro wound closure using live time-lapse microscopy. Transwell migration assay and Ki67 immunostaining were done to evaluate migration and proliferation, respectively. Lipopolysaccharide (LPS) was used to activate TLR4, whereas CLI-095 was used for its inhibition. The expression of inflammatory cytokines was determined by RT-PCR and ELISA. The activation of p42/44 and p38 was determined by immunoblotting. RESULTS: In the murine model, TLR4 immunostaining was noted prominently in the epithelium 8 hours after wounding. There was a 4-fold increase in the expression of TLR4 6 hours after in vitro scratch wounding (P < 0.001). Confocal microscopy confirmed the membrane localization of TLR4/MD2 complex. There was a significant increase in migration, proliferation, and wound closure in HCEC treated with LPS (P < 0.05), while there was significant decrease with TLR4 inhibition (P < 0.05). Addition of LPS to wounded HCEC resulted in a significant increase in the expression of IL-6, TNF-α, CXCL8/IL8, and CCL5/RANTES at the mRNA and protein levels. Likewise, LPS increased the activation of p42/44 and p38 in wounded HCEC. CONCLUSIONS: These results suggest that epithelial wounding induces the expression of functional TLR4. Toll-like receptor 4 signaling appears to contribute to early corneal epithelial wound repair by enhancing migration and proliferation.

The ocular surface chemical burns.

Ocular chemical burns are common and serious ocular emergencies that require immediate and intensive evaluation and care. The victims of such incidents are usually young, and therefore loss of vision and disfigurement could dramatically affect their lives. The clinical course can be divided into immediate, acute, early, and late reparative phases. The degree of limbal, corneal, and conjunctival involvement at the time of injury is critically associated with prognosis. The treatment starts with simple but vision saving steps and is continued with complicated surgical procedures later in the course of the disease. The goal of treatment is to restore the normal ocular surface anatomy and function. Limbal stem cell transplantation, amniotic membrane transplantation, and ultimately keratoprosthesis may be indicated depending on the patients' needs.

Loss of Notch1 disrupts the barrier repair in the corneal epithelium.

The corneal epithelium is the outermost layer of the cornea that directly faces the outside environment, hence it plays a critical barrier function. Previously, conditional loss of Notch1 on the ocular surface was found to cause inflammation and keratinization of the corneal epithelium. This was in part attributed to impaired vitamin A metabolism, loss of the meibomian glands and recurrent eyelid trauma. We hypothesized that Notch1 plays an essential role in the corneal epithelial barrier function and is a contributing factor in the pathologic changes in these mice. Notch1 was conditionally deleted in adult Notch1(flox/flox), K14-Cre-ERT(+/-) mice using hydroxy-tamoxifen. The results indicated that conditional deletion of Notch1 on the ocular surface leads to progressive impairment of the epithelial barrier function before the onset of corneal opacification and keratinization. Loss of the barrier was demonstrated both by an increase in in vivo corneal fluorescein staining and by enhanced penetration of a small molecule through the epithelium. Corneal epithelial wounding resulted in significant delay in recovery of the barrier function in conditional Notch1(-/-) mice compared to wild type. Mice with conditional deletion of Notch1 did not demonstrate any evidence of dry eyes based on aqueous tear production and had normal conjunctival goblet cells. In a calcium switch experiment in vitro, Notch1(-/-) cells demonstrated delayed membrane localization of the tight junction protein ZO-1 consistent with a defect in the epithelial tight junction formation. These findings highlight the role of Notch1 in epithelial differentiation and suggest that intrinsic defects in the corneal epithelial barrier recovery after wounding is an important contributing factor to the development of inflammatory keratinization in Notch1(-/-) mice.

Notch inhibition during corneal epithelial wound healing promotes migration.

PURPOSE: To determine the role of Notch signaling in corneal epithelial migration and wound healing. METHODS: Immunolocalization of Notch1 was performed during epithelial wound healing in vivo in mouse corneal epithelial debridement wounds and in vitro in primary human corneal epithelial cells following a linear scratch wound. The effects of Notch inhibition, using the γ-secretase inhibitor N-(N-[3,5-difluorophenacetyl]-l-alanyl)-S-phenylglycine t-butyl ester (DAPT) or following stable transfection with Notch1-short hairpin RNA (shRNA), was evaluated in a scratch assay and transwell migration assay. Likewise, in vitro adhesion, proliferation and the actin cytoskeleton was examined. The DAPT effect was also evaluated in vivo in a mouse model of corneal epithelial wound healing. RESULTS: The expression of Notch1 was reduced at the leading edge of a healing corneal epithelium both in vivo and in vitro. Notch inhibition using DAPT and using Notch1-shRNA both enhanced in vitro migration in scratch and transwell migration assays. Consistent with this increased migratory behavior, Notch inhibited cells demonstrated decreased cell-matrix adhesion and enhanced lamellipodia formation. Notch inhibition by DAPT was also found to accelerate corneal epithelial wound closure in an in vivo murine model without affecting proliferation. CONCLUSIONS: The results highlight the role of Notch in regulating corneal epithelial migration and wound healing. In particular, Notch signaling appears to decrease in the early stages of wound healing which contributes to cytoskeletal changes with subsequent augmentation of migratory behavior.

Cataract surgery in the face of ocular surface disease.

PURPOSE OF REVIEW: This article reviews the importance of ocular surface management in patients undergoing cataract surgery. The current strategies for the diagnosis and management of ocular surface disease in cataract surgery patients are discussed. RECENT FINDINGS: The current trend is to diagnose and treat ocular surface disease before cataract surgery using a stepwise regimen tailored to the individual patient and disease severity. SUMMARY: Maintaining a healthy ocular surface is essential for achieving the best visual outcome in cataract patients. Ocular surface preparation is beneficial not only in patients with established ocular surface disease, but also in those with minimal signs or symptoms of surface disease.