Early Endophthalmitis Incidence and Risk Factors after Glaucoma Surgery in the Medicare Population from 2016 to 2019

PURPOSE

To determine early endophthalmitis incidence and risk factors after glaucoma surgeries in the Medicare population.

DESIGN

Retrospective, longitudinal study.

PARTICIPANTS

Medicare Fee-for-Service (FFS) and Medicare Advantage beneficiaries in the United States aged 65 years or older undergoing glaucoma surgery.

METHODS

Medicare claims were used to identify all patients who underwent glaucoma, cataract, or combined cataract/glaucoma surgery from 2016 to 2019. Endophthalmitis cases within 42 days of the index surgery were identified using the diagnostic codes. Multivariable logistic regression models were used to evaluate factors associated with postoperative endophthalmitis.

MAIN OUTCOME MEASURES

The 42-day postoperative endophthalmitis incidence and risk factors associated with endophthalmitis after glaucoma surgery.

RESULTS

There were 466 928 glaucoma surgeries, of which 310 823 (66.6%) were combined with cataract surgery. Cataract surgeries alone (n = 8 460 360) served as a reference group. Microinvasive glaucoma surgeries constituted most glaucoma procedures performed (67.8%), followed by trabeculectomy (14.0%), tube shunt (10.9%), and other procedures (7.3%). There were 572 cases of endophthalmitis identified after all glaucoma surgeries. Endophthalmitis incidence after glaucoma, combined cataract/glaucoma, and cataract surgeries alone was 1.5 (95% confidence interval [CI], 1.3-1.7), 1.1 (95% CI, 1.0-1.2), and 0.8 (95% CI, 0.8-0.8) per 1000 procedures, respectively. The median day of diagnosis of endophthalmitis was later for glaucoma surgeries (16.5 days) compared with combined cataract/glaucoma or cataract surgeries alone (8 and 6 days, respectively). Compared with microinvasive glaucoma surgery (MIGS), tube shunts were the only surgery type to be a significant risk factor for endophthalmitis for both stand-alone (adjusted odds ratio [aOR], 1.8, P = 0.002) and combined surgery (aOR 1.8, P = 0.047). The other risk factor for both stand-alone (aOR 1.1, P = 0.001) and combined (aOR 1.06, P = 0.049) surgeries was the Charlson Comorbidity Index (CCI). Age (aOR 1.03, P = 0.004) and male gender (1.46, P = 0.001) were significant risk factors for combined cataract and glaucoma surgeries.

CONCLUSIONS

Compared with cataract surgery, early endophthalmitis incidence was higher for both glaucoma and combined cataract/glaucoma surgeries, with the highest incidence among tube shunts.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Capabilities and Limitations of Student-Led Free Vision Screening Programs in the United States

Purpose

The Consortium of Student-Led Eye Clinics (CSLEC), founded in 2021, administered a comprehensive survey to document the types of services, most common diagnoses, and follow-up care protocols offered by student-led free vision screening programs (SLFVSP) in the United States.

Methods

An 81-question institutional review board (IRB)-approved survey was administered to student-led vision screening eye clinics from October 1, 2022 to February 24, 2023.

Results

Sixteen SLFVSPs were included in the final analysis, of which 81% (n = 13) conducted variations of fundoscopic examinations and 75% (n = 12) measured intraocular pressure. Cataracts and diabetic retinopathy were reported as the most frequent diagnoses by the majority of SLFVSPs (n = 9, 56%); non-mobile SLFVSPs more commonly reported cataract as a frequent diagnosis (P < 0.05). Most patients screened at participating programs were uninsured or met federal poverty guidelines. Prescription glasses were offered by 56% of the programs (n = 9). SLFVSPs that directly scheduled follow-up appointments reported higher attendance rates (66.5%) than those that only sent referrals (20%). Transportation was the most cited barrier for follow-up appointment attendance.

Conclusions

SLFVSPs, one community vision screening initiative subtype, vary significantly in scope and capabilities of identifying vision threatening disease. The follow-up infrastructure is not uniformly robust and represents a key target for improving care delivery to at-risk populations.

Translational Relevance

The CSLEC aims to develop a consensus-based standardization for the scope of screening services, offer guidelines for diagnostic criteria, promote real-time data stewardship, and identify means to improve follow-up care mechanisms in member communities.

Comparison of the Biomechanics of the Mouse Astrocytic Lamina Cribrosa Between Glaucoma and Optic Nerve Crush Models

Purpose

The strain response of the mouse astrocytic lamina (AL) to an ex vivo mechanical test was compared between two protocols: eyes that underwent sustained intraocular pressure (IOP) increase and eyes after optic nerve crush.

Methods

Chronic IOP elevation was induced by microbead injection or the optic nerve was crushed in mice with widespread green fluorescence. After 3 days or 6 weeks, eyes were inflation tested by a published method of two-photon fluorescence to image the AL. Digital volume correlation was used to calculate strains. Optic nerve axon damage was also evaluated.

Results

In the central AL but not the peripheral AL, four strains were greater in eyes at the 3-day glaucoma time point than control (P from 0.029 to 0.049, n = 8 eyes per group). Also, at this time point, five strains were greater in the central AL compared to the peripheral AL (P from 0.041 to 0.00003). At the 6-week glaucoma time point, the strains averaged across the specimen, in the central AL, and the peripheral AL were indistinguishable from the respective controls. Strains were not significantly different between controls and eyes 3 days or 6 weeks after crush (n = 8 and 16).

Conclusions

We found alterations in the ex vivo mechanical behavior in eyes from mice with experimental glaucoma but not in those with crushed optic nerves. The results of this study demonstrate that significant axon injury does not directly affect mechanical behavior of the astrocytic lamina.

The Retinal Ganglion Cell Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration Consortium

Purpose

The Retinal Ganglion Cell (RGC) Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) consortium was founded in 2021 to help address the numerous scientific and clinical obstacles that impede development of vision-restorative treatments for patients with optic neuropathies. The goals of the RReSTORe consortium are: (1) to define and prioritize the most critical challenges and questions related to RGC regeneration; (2) to brainstorm innovative tools and experimental approaches to meet these challenges; and (3) to foster opportunities for collaborative scientific research among diverse investigators.

Design and Participants

The RReSTORe consortium currently includes > 220 members spanning all career stages worldwide and is directed by an organizing committee comprised of 15 leading scientists and physician-scientists of diverse backgrounds.

Methods

Herein, we describe the structure and organization of the RReSTORe consortium, its activities to date, and the perceived impact that the consortium has had on the field based on a survey of participants.

Results

In addition to helping propel the field of regenerative medicine as applied to optic neuropathies, the RReSTORe consortium serves as a framework for developing large collaborative groups aimed at tackling audacious goals that may be expanded beyond ophthalmology and vision science.

Conclusions

The development of innovative interventions capable of restoring vision for patients suffering from optic neuropathy would be transformative for the ophthalmology field, and may set the stage for functional restoration in other central nervous system disorders. By coordinating large-scale, international collaborations among scientists with diverse and complementary expertise, we are confident that the RReSTORe consortium will help to accelerate the field toward clinical translation.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Prediction of MIGS outcomes on second eyes using first eyes' response

To evaluate how well outcomes following cataract extraction and microinvasive glaucoma surgery in one eye predict outcomes in sequential second eye. Retrospective study of 78 patients who underwent cataract extraction and microinvasive glaucoma surgery in both eyes. Linear regressions using Pearson correlation coefficients were used to evaluate correlations in intraocular pressure and glaucoma medication change between eyes. Multivariable logistic regression models were used to evaluate the associations between first-eye variables and the likelihood of second-eye surgical success at 6 months. Surgical success was defined as meeting target intraocular pressure without additional medications compared to baseline or secondary surgical interventions. Baseline ocular characteristics were comparable between fellow eyes, with the majority having mild glaucoma. Intraocular pressure changes between fellow eyes at 6 months were modestly correlated between eyes (R = 0.48; P < .001). Changes in glaucoma medications were strongly correlated between eyes at all time points, and month 6 demonstrated the most significant correlation (R = 0.80; P < .001). First and second eye cohorts achieved 82% and 83% surgical success. Multivariate analysis for predictive factors of successful second eye surgery showed patients with successful first eye surgery at 6 months were significantly more likely to have successful second eye surgery (odds ratio, 20.67; P < .001). Reductions in intraocular pressure and glaucoma medications at 6 months following surgery in first eyes are correlated to second eye reductions. Successful surgical outcomes at 6 months following first eye surgeries are strongly associated with successful sequential second eye outcomes.

Rare intercellular material transfer as a confound to interpreting inner retinal neuronal transplantation following internal limiting membrane disruption

Intercellular cytoplasmic material transfer (MT) occurs between transplanted and developing photoreceptors and ambiguates cell origin identification in developmental, transdifferentiation, and transplantation experiments. Whether MT is a photoreceptor-specific phenomenon is unclear. Retinal ganglion cell (RGC) replacement, through transdifferentiation or transplantation, holds potential for restoring vision in optic neuropathies. During careful assessment for MT following human stem cell-derived RGC transplantation into mice, we identified RGC xenografts occasionally giving rise to labeling of donor-derived cytoplasmic, nuclear, and mitochondrial proteins within recipient Müller glia. Critically, nuclear organization is distinct between human and murine retinal neurons, which enables unequivocal discrimination of donor from host cells. MT was greatly facilitated by internal limiting membrane disruption, which also augments retinal engraftment following transplantation. Our findings demonstrate that retinal MT is not unique to photoreceptors and challenge the isolated use of species-specific immunofluorescent markers for xenotransplant identification. Assessment for MT is critical when analyzing neuronal replacement interventions.

ACR Appropriateness Criteria® Preprocedural Planning for Transcatheter Aortic Valve Replacement: 2023 Update

This document discusses preprocedural planning for transcatheter aortic valve replacement, evaluating the imaging modalities used in initial imaging for preprocedure planning under two variants 1) Preintervention planning for transcatheter aortic valve replacement: assessment of aortic root; and 2) Preintervention planning for transcatheter aortic valve replacement: assessment of supravalvular aorta and vascular access. US echocardiography transesophageal, MRI heart function and morphology without and with IV contrast, MRI heart function and morphology without IV contrast and CT heart function and morphology with IV contrast are usually appropriate for assessment of aortic root. CTA chest with IV contrast, CTA abdomen and pelvis with IV contrast, CTA chest abdomen pelvis with IV contrast are usually appropriate for assessment of supravalvular aorta and vascular access. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium

Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.

Regional Gene Expression in the Retina, Optic Nerve Head, and Optic Nerve of Mice with Optic Nerve Crush and Experimental Glaucoma

A major risk factor for glaucomatous optic neuropathy is the level of intraocular pressure (IOP), which can lead to retinal ganglion cell axon injury and cell death. The optic nerve has a rostral unmyelinated portion at the optic nerve head followed by a caudal myelinated region. The unmyelinated region is differentially susceptible to IOP-induced damage in rodent models and human glaucoma. While several studies have analyzed gene expression changes in the mouse optic nerve following optic nerve injury, few were designed to consider the regional gene expression differences that exist between these distinct areas. We performed bulk RNA-sequencing on the retina and separately micro-dissected unmyelinated and myelinated optic nerve regions from naïve C57BL/6 mice, mice after optic nerve crush, and mice with microbead-induced experimental glaucoma (total = 36). Gene expression patterns in the naïve unmyelinated optic nerve showed significant enrichment of the Wnt, Hippo, PI3K-Akt, and transforming growth factor β pathways, as well as extracellular matrix-receptor and cell membrane signaling pathways, compared to the myelinated optic nerve and retina. Gene expression changes induced by both injuries were more extensive in the myelinated optic nerve than the unmyelinated region, and greater after nerve crush than glaucoma. Changes present three and fourteen days after injury largely subsided by six weeks. Gene markers of reactive astrocytes did not consistently differ between injury states. Overall, the transcriptomic phenotype of the mouse unmyelinated optic nerve was significantly different from immediately adjacent tissues, likely dominated by expression in astrocytes, whose junctional complexes are inherently important in responding to IOP elevation.

Short-Term Outcomes of Hydrus Microstent With and Without Additional Canaloplasty During Cataract Surgery

PRCIS

Compared with phacoemulsification and microstent alone, we observed that phacoemulsification with combined microstent and canaloplasty resulted in a significantly greater reduction in glaucoma medications while maintaining similar rates of intraocular pressure reduction and low complications.

PURPOSE

The purpose of this study was to compare the outcomes of phacoemulsification combined with Hydrus Microstent (Alcon Inc.) implantation alone or in combination with canaloplasty (OMNI Surgical System, Sight Sciences Inc.).

MATERIALS AND METHODS

Retrospective study of mild-to-moderate primary open angle glaucoma patients who underwent phacoemulsification with microstent alone (42 eyes of 42 patients) or in combination with canaloplasty (canaloplasty-microstent, 32 eyes of 32 patients). The mean number of ocular hypotensive medications and intraocular pressure were assessed preoperatively and postoperatively at 1 week and at 1, 3, and 6 months. Complications and secondary surgical interventions were recorded. Outcomes measures included the percentage of unmedicated eyes and surgical success at 6 months. Surgical success was defined as reaching the target intraocular pressure without medications or secondary surgical interventions.

RESULTS

Mean intraocular pressure at 6 months was 14.1±3.5 mm Hg (13% reduction) after microstent alone and 13.6±3.1 mm Hg (17% reduction) after canaloplasty-microstent. Mean medications at 6 months were 0.57±0.9 (67% reduction) after microstent alone and 0.16±0.4 (88% reduction) after canaloplasty-microstent ( P< 0.05). At 6 months, 64.3% of microstent alone and 87.3% of canaloplasty-microstent were off all medications ( P =0.02). Success probabilities at 6 months were 44.5% for microstent alone and 70.0% for canaloplasty-microstent ( P =0.04). No secondary surgical interventions occurred in either group.

CONCLUSIONS

Microstent combined with canaloplasty resulted in a significantly higher rate of medication-free status compared with microstent alone through 6 months.

Comparing Ahmed-FP7 to Baerveldt-250 and Baerveldt-350 surgical outcomes: 1-year results from a retrospective cohort study leveraging the electronic health record

OBJECTIVE

To compare outcomes following Ahmed-FP7 (AGI-FP7), Baerveldt-250mm2 (BGI-250), or Baerveldt-350mm2 (BGI-350) implantation.

METHODS AND ANALYSIS

Retrospective cohort study comprising 800 eyes from 800 individuals who underwent surgery 1 January 2016-31 December 2020 at a tertiary-care institution. Data were extracted from standardised fields in the electronic health record. Primary outcome was failure (defined as intraocular pressure (IOP) ≤5 mm Hg or >18 mm Hg or reduction <20% at two consecutive visits from month 3 onwards; or visual acuity (VA) loss ≥3 lines; or return to the operating room (OR)). Secondary outcomes were IOP, VA, number of follow-up visits and return to the OR.

RESULTS

A total of 523 AGI-FP7, 133 BGI-250 and 144 BGI-350 cases were analysed. The AGI-FP7 group was more likely to be younger and diagnosed with secondary glaucoma, with a higher mean baseline IOP (28.5±12.2 vs 22.0±7.7 mm Hg in BGI-250 and 23.4±9.0 in BGI-350, p<0.001). Cumulative failure rate at month 12 was 30% (AGI-FP7) vs 39% (BGI-250) vs 33% (BGI-350, p=0.159). Mean IOP at month 12 was lower in the BGI-350 group compared with AGI-FP7 (12.4±4.4 vs 14.8±5.6 mm Hg, p=0.003) but not BGI-250 (vs 13.1±4.6, p=0.710). Target IOP was achieved in 71% of AGI-FP7, 66% BGI-250, and 76% BGI-350. VA loss and rates of return to the OR did not differ between groups. Both BGI-250 and BGI-350 had more follow-up visits than AGI-FP7 (p<0.001).

CONCLUSION

These three glaucoma drainage devices performed similarly within 1 year, with no difference in failure rates despite differing baseline patient characteristics.

Regional Gene Expression in the Retina, Optic Nerve Head, and Optic Nerve of Mice with Experimental Glaucoma and Optic Nerve Crush

A major risk factor for glaucomatous optic neuropathy is the level of intraocular pressure (IOP), which can lead to retinal ganglion cell axon injury and cell death. The optic nerve has a rostral unmyelinated portion at the optic nerve head followed by a caudal myelinated region. The unmyelinated region is differentially susceptible to IOP-induced damage in rodent models and in human glaucoma. While several studies have analyzed gene expression changes in the mouse optic nerve following optic nerve injury, few were designed to consider the regional gene expression differences that exist between these distinct areas. We performed bulk RNA-sequencing on the retina and on separately micro-dissected unmyelinated and myelinated optic nerve regions from naïve C57BL/6 mice, mice after optic nerve crush, and mice with microbead-induced experimental glaucoma (total = 36). Gene expression patterns in the naïve unmyelinated optic nerve showed significant enrichment of the Wnt, Hippo, PI3K-Akt, and transforming growth factor β pathways, as well as extracellular matrix-receptor and cell membrane signaling pathways, compared to the myelinated optic nerve and retina. Gene expression changes induced by both injuries were more extensive in the myelinated optic nerve than the unmyelinated region, and greater after nerve crush than glaucoma. Changes three and fourteen days after injury largely subsided by six weeks. Gene markers of reactive astrocytes did not consistently differ between injury states. Overall, the transcriptomic phenotype of the mouse unmyelinated optic nerve was significantly different from immediately adjacent tissues, likely dominated by expression in astrocytes, whose junctional complexes are inherently important in responding to IOP elevation.

The importance of unambiguous cell origin determination in neuronal repopulation studies

Neuronal repopulation achieved through transplantation or transdifferentiation from endogenous sources holds tremendous potential for restoring function in chronic neurodegenerative disease or acute injury. Key to the evaluation of neuronal engraftment is the definitive discrimination of new or donor neurons from preexisting cells within the host tissue. Recent work has identified mechanisms by which genetically encoded donor cell reporters can be transferred to host neurons through intercellular material transfer. In addition, labeling transplanted and endogenously transdifferentiated neurons through viral vector transduction can yield misexpression in host cells in some circumstances. These issues can confound the tracking and evaluation of repopulated neurons in regenerative experimental paradigms. Using the retina as an example, we discuss common reasons for artifactual labeling of endogenous host neurons with donor cell reporters and suggest strategies to prevent erroneous conclusions based on misidentification of cell origin.

HIF-1α accumulation in response to transient hypoglycemia may worsen diabetic eye disease

Tight glycemic control (TGC), the cornerstone of diabetic management, reduces the incidence and progression of diabetic microvascular disease. However, TGC can also lead to transient episodes of hypoglycemia, which have been associated with adverse outcomes in patients with diabetes. Here, we demonstrate that low glucose levels result in hypoxia-inducible factor (HIF)-1-dependent expression of the glucose transporter, Glut1, in retinal cells. Enhanced nuclear accumulation of HIF-1α was independent of its canonical post-translational stabilization but instead dependent on stimulation of its translation and nuclear localization. In the presence of hypoxia, this physiologic response to low glucose resulted in a marked increase in the secretion of the HIF-dependent vasoactive mediators that promote diabetic retinopathy. Our results provide a molecular explanation for how early glucose control, as well as glycemic variability (i.e., oscillating serum glucose levels), contributes to diabetic eye disease. These observations have important implications for optimizing glucose management in patients with diabetes.

Effects of experimental glaucoma in Lama1nmf223 mutant mice

To identify changes in response to experimental intraocular pressure (IOP) elevation associated with the laminin α1 nmf223 mutation in mice. Laminin mutant (LM) mice (Lama1^nmf223) and C57BL/6J (B6) mice in two age groups each (4-5 months and >1 year) underwent intracameral microbead injections to produce unilaterally elevated IOP. We assessed axonal transport block of immunofluorescently labeled amyloid precursor protein (APP) after 3 days and retinal ganglion cell (RGC) axon loss after 6 weeks. Light, electron and fluorescent microscopy was used to study baseline anatomic differences and effects of 3-day IOP elevation in younger LM mice. In younger mice of both LM and B6 strains, elevated IOP led to increased APP block in the retina, prelaminar optic nerve head (preONH), unmyelinated optic nerve (UON), and myelinated optic nerve (MON). APP blockade not significantly different between younger B6 and LM mouse strains. Older LM mice had greater APP accumulation in both control and glaucoma eyes compared to older B6, however, accumulation was not significantly greater in LM glaucoma eyes compared to LM controls. Axon loss at 6 weeks was 12.2% in younger LM and 18.7% in younger B6 mice (difference between strains, p = 0.22, Mann Whitney test). Untreated LM optic nerve area was lower compared to B6 (nerve area, p < 0.0001, t-test). Aberrant axon bundles, as well as defects, thickening and reduplication of pia mater, were seen in the optic nerves of younger LM mice. Axonal transport blockade significantly differed between old B6 and old LM mice in control and glaucoma eyes, and younger LM mice had abnormal axon paths and lower optic nerve area.

Formulation and Evaluation of Polymer-Based Nanoparticles for Intravitreal Gene-Delivery Applications

The advent of the first-ever retinal gene therapy product, involving subretinal administration of a virus-based gene delivery platform, has garnered hope that this state-of-the-art therapeutic modality may benefit a broad spectrum of patients with diverse retinal disorders. On the other hand, clinical studies have revealed limitations of the applied delivery strategy that may restrict its universal use. To this end, intravitreal administration of synthetic gene-delivery platforms, such as polymer-based nanoparticles (PNPs), has emerged as an attractive alternative to the current mainstay. To achieve success, however, it is imperative that synthetic platforms overcome key biological barriers in human eyes encountered following intravitreal administration, including the vitreous gel and inner limiting membrane (ILM). Here, we introduce a series of experiments, from the fabrication of PNPs to a comprehensive evaluation in relevant experimental models, to determine whether PNPs overcome these barriers and efficiently deliver therapeutic gene payloads to retinal cells. We conclude the article by discussing a few important considerations for successful implementation of the strategy. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Preparation and characterization of PNPs Basic Protocol 2: Evaluation of in vitro transfection efficacy Basic Protocol 3: Evaluation of PNP diffusion in vitreous gel Basic Protocol 4: Ex vivo assessment of PNP penetration within vitreoretinal explant culture Basic Protocol 5: Assessment of in vivo transgene expression mediated by intravitreally administered PNPs.

Quantitative Microstructural Analysis of Cellular and Tissue Remodeling in Human Glaucoma Optic Nerve Head

Purpose

To measure quantitatively changes in lamina cribrosa (LC) cell and connective tissue structure in human glaucoma eyes.

Methods

We studied 27 glaucoma and 19 age-matched non-glaucoma postmortem eyes. In 25 eyes, LC cross-sections were examined by confocal and multiphoton microscopy to quantify structures identified by anti-glial fibrillary acidic protein (GFAP), phalloidin-labeled F-actin, nuclear 4',6-diamidino-2-phenylindole (DAPI), and by second harmonic generation imaging of LC beams. Additional light and transmission electron microscopy were performed in 21 eyes to confirm features of LC remodeling, including immunolabeling by anti-SOX9 and anti-collagen IV. All glaucoma eyes had detailed clinical histories of open-angle glaucoma status, and degree of axon loss was quantified in retrolaminar optic nerve cross-sections.

Results

Within LC pores, the proportionate area of both GFAP and F-actin processes was significantly lower in glaucoma eyes than in controls (P = 0.01). Nuclei were rounder (lower median aspect ratio) in glaucoma specimens (P = 0.02). In models assessing degree of glaucoma damage, F-actin process width was significantly wider in glaucoma eyes with more damage (P = 0.024), average LC beam width decreased with worse glaucoma damage (P = 0.042), and nuclear count per square millimeter rose with worse damage (P = 0.019). The greater cell count in LC pores represented 92.3% astrocytes by SOX9 labeling. The results are consistent with replacement of axons in LC pores by basement membrane labeled by anti-collagen IV and in-migrating astrocytes.

Conclusions

Alteration in LC structure in glaucoma involves migration of astrocytes into axonal bundles, change in astrocyte orientation and processes, production of basement membrane material, and thinning of connective tissue beams.

The utility of home tonometry for peri-interventional decision-making in glaucoma surgery: Case series

Purpose

To describe twelve cases in which home intraocular pressure (IOP) monitoring complimented clinical decision-making in glaucoma management.

Observations

Home IOP monitoring elucidated peaks and amplitudes of variation that were not captured by in-clinic IOP measurements during the pre- or post-interventional period.

Conclusions & Importance

Home monitoring can establish pre-treatment IOP patterns that are not evident during in-clinic measurements. Home monitoring can also demonstrate response to treatment more quickly than in-clinic monitoring, and provide more information about nyctohemoral fluctuations than is ascertained by in-clinic tonometry.

Association Between Open Payments-Reported Industry Transfers of Value and Prostaglandin Analog Prescribing in the US

Importance

Reported transfers of value (TOV) from pharmaceutical companies have been associated with greater use of branded anti-vascular endothelial growth factor agents by ophthalmologists, but payment under the Medicare Part B buy-and-bill model includes a financial incentive to choose costlier agents, potentially confounding analyses of pharmaceutical TOV and prescribing patterns. How these reported TOV are associated with prescribing patterns for prescription eye drops, not subject to the incentives created by Part B payments, should be considered.

Objective

To assess the association between prostaglandin analog (PGA) eye drop prescribing and reported nonresearch TOV by makers of branded PGAs to US vision care professionals.

Design, Setting, and Participants

This retrospective cohort analysis used a 20% nationally representative sample of 2018 Medicare Part D claims and industry TOV reported to the Open Payments program. Optometrists and ophthalmologists who had more than 10 claims for PGA drops in the 20% sample were analyzed. Analysis took place from June 2021 to February 2022.

Main Outcomes and Measures

Multivariable logistic regression assessing the association between membership in strata of reported TOV and branded PGA prescribing rate, controlling for prescriber demographic factors, local area practices, total PGA prescribing volume, and plan formularies involved.

Results

A total of 20 612 ophthalmologists and 5426 optometrists (7449 [29%] female and 18 589 [71%] male) prescribed PGA eye drops. Of these, 9685 (37%) were reported to have received TOV from manufacturers of branded PGAs in 2018, totaling $5 060 346. The median (IQR) reported TOV was $65 ($24-$147). Multivariable logistic regression showed that the predicted probability of primarily prescribing branded PGAs among prescribers who reported receiving no TOV was 12.9% (95% CI, 12.4%-13.4%). This figure increased to 19.6% (95% CI, 18.8%-20.4%) among prescribers receiving TOV, a 50% increase. There was a dose-response association, such that the top 10% of TOV recipients had a 29.2% probability (95% CI, 26.4%-31.9%) of preferential branded use.

Conclusions and Relevance

While the median reported TOV to a PGA prescriber was relatively low in this study, there was a positive association between amount of reported nonresearch TOV received from PGA makers and the frequency of branded PGA use. This shows that small reported TOV were associated with differences in prescribing. High rates of branded PGA prescribing may pose a cost burden to patients that affects adherence. Clinicians and policy makers should be aware of these associations.

Aquaporin 4 is not present in normal porcine and human lamina cribrosa

Aquaporin 4 is absent from astrocytes in the rodent optic nerve head, despite high expression in the retina and myelinated optic nerve. The purpose of this study was to quantify regional aquaporin channel expression in astrocytes of the porcine and human mouse optic nerve (ON). Ocular tissue sections were immunolabeled for aquaporins 1(AQP1), 4(AQP4), and 9(AQP9), myelin basic protein (MBP), glial fibrillary acidic protein (GFAP) and alpha-dystroglycan (αDG) for their presence in retina, lamina, myelin transition zone (MTZ, region just posterior to lamina) and myelinated ON (MON). Semi- quantification of AQP4 labeling & real-time quantitative PCR (qPCR) data were analyzed in retina and ON tissue. Porcine and control human eyes had abundant AQP4 in Müller cells, retinal astrocytes, and myelinated ON (MON), but minimal expression in the lamina cribrosa. AQP1 and AQP9 were present in retina, but not in the lamina. Immunolabeling of GFAP and αDG was similar in lamina, myelin transition zone (MTZ) and MON regions. Semi-quantitative AQP4 labeling was at background level in lamina, increasing in the MTZ, and highest in the MON (lamina vs MTZ, MON; p≤0.05, p≤0.01, respectively). Expression of AQP4 mRNA was minimal in lamina and substantial in MTZ and MON, while GFAP mRNA expression was uniform among the lamina, MTZ, and MON regions. Western blot assay showed AQP4 protein expression in the MON samples, but none was detected in the lamina tissue. The minimal presence of AQP4 in the lamina is a specific regional phenotype of astrocytes in the mammalian optic nerve head.

Retina-sparing suprachoroidal intraocular foreign body resulting in cyclodialysis cleft

Purpose

Suprachoroidal intraocular foreign bodies (IOFBs) are an exceedingly rare manifestation of ocular trauma. Here we present a unique case of a metallic wire tracking from the cornea through the suprachoroidal space, and remarkably sparing the retina and lens. The patient attained an excellent visual outcome after management of resultant cyclodialysis cleft.

Observations

A 34-year-old male experienced a penetrating IOFB while operating a rotary wire brush. He presented to the emergency department where posterior involvement of the IOFB was confirmed on CT scan. He underwent emergent pars plana vitrectomy, during which the IOFB was found to be located underneath intact retina and choroid on scleral depression. The wire was removed through the entry wound, which was self-sealing. At follow up, intraocular pressure was 3 mmHg with findings of hypotony. A cyclodialysis cleft was confirmed with ultrasound biomicroscopy. Cycloplegic and photocoagulation treatments were attempted, but ultimately direct cyclopexy was performed to successfully repair the cleft. One year after the initial incident, visual acuity is 20/25 and IOP is 17 mmHg.

Conclusion and importance

Cyclodialysis cleft is a rare sequela of penetrating ocular injury. Clinicians should consider the presence of a cyclodialysis cleft in the setting of postoperative hypotony and confirm either with gonioscopy or other anterior segment imaging methods. Despite failure of conservative therapies, our patient had an excellent visual outcome following surgical closure of the cleft.

Analyses of transplanted human retinal ganglion cell morphology and localization in murine organotypic retinal explant culture

Retinal ganglion cell (RGC) transplantation has the potential to restore vision in optic neuropathy, but donor neuron survival and retinal integration remain challenging. Here, we present a protocol for ex vivo human RGC transplantation on flatmounted murine organotypic retinal explants, providing a robust platform for studying donor RGC survival, dendritic stratification, topographic distribution, donor-host interactions, and pro-engraftment strategies. The protocol includes microscopy-based analyses to evaluate donor cell engraftment and can be adapted to various donor cell types or culture systems.

For complete details on the use and execution of this protocol, please refer to Zhang et al. (2021a, 2021b).

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Protocol for murine organotypic retinal explant culture with RGC transplantation

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Proteolytic digestion of the internal limiting membrane enhances engraftment

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Microscopy-based analyses quantify donor RGC survival and topology

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Three-dimensional microscopy reconstructions localize donor neurite engraftment

Demographics, clinical interests, and ophthalmology skills confidence of medical student volunteers and non-volunteers in an extracurricular community vision screening service-learning program

BACKGROUND

Medical school curricular hours dedicated to ophthalmology are low and declining. Extracurricular ophthalmology activities, such as participation in community vision screenings, may serve an important adjunctive role in medical school curricula. The Johns Hopkins University (JHU) Vision Screening In Our Neighborhoods (ViSION) Program is an example of a voluntary medical student-directed community service-learning program.

METHODS

We used a mixed-methods cross-sectional approach, including an online survey and semi-structured interviews. JHU School of Medicine students enrolled in MD or MD/PhD programs during the 2019-2020 academic year were surveyed regarding demographics, career and service interests, involvement in ophthalmology-related activities, and confidence in their ophthalmology-related skills. Survey responses were compared between ViSION volunteers and non-volunteers using Fisher's exact chi-square tests. Semi-structured interviews were conducted via webconference with 8 prior or current ViSION volunteers and responses analyzed using inductive thematic analysis. Data were collected when ViSION volunteers were in variable stages of their medical education and involvement with the ViSION program.

RESULTS

A total of 118 medical students were included, representing an overall response rate of 24.6% of JHU medical students. ViSION volunteers reported greater involvement in ophthalmology-related research (42% vs. 4%, p < 0.001), intent to apply to ophthalmology residency programs (35% vs. 1%, p = 0.001), and confidence with multiple ophthalmology knowledge and clinical skill domains. In particular, ViSION volunteers were more likely to feel confident estimating cup-to-disc ratio using direct ophthalmoscopy (20% vs. 0%, p < 0.001). In open-ended survey and interview questions, most volunteers attributed at least some degree of their ophthalmology skill development and desire to pursue ophthalmology and public health careers to their ViSION experience.

CONCLUSIONS

Medical students who volunteered with a student-led community vision screening program were more likely to have a prior interest in ophthalmology than those who did not volunteer, but only 1/3 of volunteers planned to pursue a career in ophthalmology. Overall, volunteers reported higher confidence performing ophthalmology-related clinical skills, suggesting that student-led community vision screening programs may provide an important avenue for medical students to explore public health aspects of ophthalmology, while practicing ophthalmology exam skills and learning about common ophthalmic pathologies, regardless of their career intentions.

Electronically Monitored Corticosteroid Eye Drop Adherence after Trabeculectomy Compared to Surgical Success

OBJECTIVE

To compare electronically measured adherence with topical corticosteroid drops to outcomes of glaucoma surgery.

DESIGN

This prospective cohort study included eyes undergoing surgery from August 2019 to January 2021 and followed for up to 1 year.

PARTICIPANTS

All patients were recruited from the Glaucoma Center of Excellence at the Wilmer Eye Institute, Johns Hopkins. Eligible patients had either primary open angle or angle closure glaucoma, were ≥18 years old, and underwent either trabeculectomy (with or without cataract surgery) or tube-shunt implantation.

INTERVENTION

Patients were instructed on use of an eyedrop monitoring device (Kali Drop®), with knowledge that it would be used to record postoperative corticosteroid instillation in real time.

MAIN OUTCOMES

Adherence to a regimen of corticosteroid eye drops during the first 5 postoperative weeks; achievement of target intraocular pressure (IOP) at 6 weeks, 6 months to 1 year after surgery; and bleb morphology at 1 year.

RESULTS

Among 90 patients, adherence was 90 ± 14% overall and 81 ± 16% during q2h dosing. Target IOP was achieved at final visit (6 months or 1 year) in 81% (59/73) without reoperation. Eyes with a higher ratio of drops taken vs prescribed were significantly more likely to achieve target IOP at 6 months/1 year (p=0.05). Total adherence was better in younger persons, eyes with less field loss, and patients of one particular surgeon (p<0.03). Percent adherence during every 2 hours (q2h) dosing was higher in eyes with higher target IOP (p=0.01). No adherence outcome was significantly related to race, sex, bleb morphology, postoperative pain, or post-operative anterior chamber inflammation. Adherence values did not significantly correlate with adherence questionnaire data (predicted mean = 70 ± 17%, actual mean = 91 ± 13% adherent, p < 0.001).

CONCLUSION

Adherence with frequent postoperative eye drops was high and can be successfully monitored remotely. Surgical success was greater among eyes with nearly ideal adherence and was poorer in older persons and those with more advanced glaucoma.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03402802.

Restoring partial vision to a blind patient

This paper reports an important breakthrough in partially restoring sight to a man who had lost his vision due to retinitis pigmentosa (RP), a heritable retinal degenerative disease that affects approximately 1 in 4000 people. Long considered an insurmountable challenge, a stellar team of vision scientists, engineers, basic biologists, and others, working together for many years, has enabled a man who had been legally blind for decades to begin distinguishing objects and navigating his environment¹.

Applicant Characteristics Associated with Glaucoma Fellowship Match from 2010 to 2017

PURPOSE

To describe trends in the glaucoma fellowship match results, glaucoma applicant characteristics, and applicant characteristics associated with matching.

DESIGN

Retrospective study.

PARTICIPANTS

Ophthalmology fellowship applicants participating in the San Francisco (SF) Match between 2010 and 2017.

METHODS

De-identified, individual applicant data provided by the San Francisco (SF) Match were used to describe glaucoma fellowship match trends and applicant characteristics between 2010 and 2017. Publicly available, conglomerate SF Match data were used to determine trends in the number of programs participating in the glaucoma fellowship match, as well as the number of positions offered and filled from 2014 to 2019. All trends analyses were performed using linear regression models on log-transformed response variables. Summary statistics for applicants who matched in glaucoma were compared with those who did not match. A multivariable logistic regression model was used to evaluate factors associated with matching in glaucoma fellowship.

MAIN OUTCOME MEASURES

Fellowship match status (matched in glaucoma vs. did not match in any ophthalmology subspecialty).

RESULTS

From 2010 to 2019, the number of matched glaucoma fellowship applicants increased from 54 to 77 (mean 3.3% per year, P = 0.001), and the proportion of applicants to any ophthalmology fellowship who matched in glaucoma increased from 13% to 15.5% (mean, 3% per year; P = 0.041). Compared with applicants who did not match in any specialty between 2010 and 2017, matched glaucoma applicants were more likely to have graduated from a top 10 residency program (10.7% vs. 4.5%, P < 0.001), U.S. medical school (93.1% vs. 39.1%, P < 0.001), or U.S. residency program (95.0% vs. 42.2%, P < 0.001), and complete more interviews (9 vs. 1, P < 0.001). After controlling for potential covariates, factors associated with increased odds of matching in glaucoma included graduating from a U.S. residency program (odds ratio [OR], 9.91; 95% confidence interval [CI], 5.45-18.03), applying to fewer programs (OR, 0.91; 95% CI, 0.88-0.93), and completing a greater number of interviews (OR, 1.49; CI, 1.39-1.60). United States Medical Licensing Examination (USMLE) Step scores were not associated with matching in glaucoma.

CONCLUSIONS

The number of applicants who matched in glaucoma fellowship increased from 2010 to 2019. Factors associated with matching in glaucoma were graduating from a U.S. residency program and completing more interviews.

ACR Appropriateness Criteria® Asymptomatic Patient at Risk for Coronary Artery Disease: 2021 Update

Coronary atherosclerotic disease is a leading cause of mortality and morbidity due to major cardiovascular events in the United States and abroad. Risk stratification and early preventive measures can reduce major cardiovascular events given the long latent asymptomatic period. Imaging tests can detect subclinical coronary atherosclerosis and aid initiation of targeted preventative efforts based on patient risk. A summary of available imaging tests for low-, intermediate-, and high-risk asymptomatic patients is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Syncope

Syncope and presyncope lead to well over one million emergency room visits in the United States each year. Elucidating the cause of syncope or presyncope, which are grouped together given similar etiologies and outcomes, can be exceedingly difficult given the diverse etiologies. This becomes more challenging as some causes, such as vasovagal syncope, are relatively innocuous while others, such as cardiac-related syncope, carry a significant increased risk of death. While the mainstay of syncope and presyncope assessment is a detailed history and physical examination, imaging can play a role in certain situations. In patients where a cardiovascular etiology is suspected based on the appropriate history, physical examination, and ECG findings, resting transthoracic echocardiography is usually considered appropriate for the initial imaging. While no imaging studies are considered usually appropriate when there is a low probability of cardiac or neurologic pathology, chest radiography may be appropriate in certain clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Home Self-tonometry Trials Compared with Clinic Tonometry in Patients with Glaucoma

PURPOSE

This study examined characteristics of intraocular pressure (IOP) as measured during home tonometry in comparison with in-clinic tonometry in patients with glaucoma.

DESIGN

Retrospective cross-sectional study of glaucoma patients who completed 1 week of self-tonometry at a single academic center.

PARTICIPANTS

Patients with glaucoma who completed home tonometry trials with the iCare HOME tonometer (iCare USA) for any reason.

METHODS

Home IOP measurements were compared with in-clinic tonometry performed during the 5 visits preceding home tonometry. Maximum daily IOP was correlated to time of day. Generalized estimating equations were used to evaluate patient characteristics and clinic-derived variables that predicted differences between home and clinic IOP.

MAIN OUTCOME MEASURES

IOP mean, maximum, minimum, range, standard deviation and coefficient of variation were compared between clinic and home tonometry. IOP mean daily maximum (MDM) and mean daily range were calulated to describe recurrent IOP spiking.

RESULTS

A total of 107 eyes from 61 patients were analyzed. Mean age was 63.2 years (standard deviation [SD], 14.0 years) and 59.0% were women. Mean clinic and home IOPs were 14.5 mmHg (SD, 4.7 mmHg) and 13.6 mmHg (SD, 5.1 mmHg). Home tonometry identified significantly higher maximum IOP, lower minimum IOP, and greater IOP range than clinic tonometry (P < 0.001). Maximum daily IOP occurred outside of clinic hours (8 am-5 pm) on 50% of days assessed and occurred between 4:30 am and 8 am on 24% of days. Mean daily maximum IOP exceeded maximum clinic IOP in 44% of patients and exceeded target IOP by 3 mmHg, 5 mmHg, or 10 mmHg in 31%, 15%, and 6% of patients, respectively. Patient characteristics that predicted significant deviations between MDM and mean clinic IOP or target IOP in multivariate models included younger age, male gender, and absence of prior filtering surgery.

CONCLUSIONS

Self-tonometry provides IOP data that supplements in-clinic tonometry and would not be detectable over daytime in-clinic diurnal curves. A subset of patients in whom home tonometry was ordered by their glaucoma clinician because of suspicion of occult IOP elevation demonstrated reproducible IOP elevation outside of the clinic setting. Such patients tended to be younger and male and not to have undergone previous filtering surgery.

The internal limiting membrane: Roles in retinal development and implications for emerging ocular therapies

Basement membranes help to establish, maintain, and separate their associated tissues. They also provide growth and signaling substrates for nearby resident cells. The internal limiting membrane (ILM) is the basement membrane at the ocular vitreoretinal interface. While the ILM is essential for normal retinal development, it is dispensable in adulthood. Moreover, the ILM may constitute a significant barrier to emerging ocular therapeutics, such as viral gene therapy or stem cell transplantation. Here we take a neurodevelopmental perspective in examining how retinal neurons, glia, and vasculature interact with individual extracellular matrix constituents at the ILM. In addition, we review evidence that the ILM may impede novel ocular therapies and discuss approaches for achieving retinal parenchymal targeting of gene vectors and cell transplants delivered into the vitreous cavity by manipulating interactions with the ILM.

An Algorithm for Ramp Up of Ophthalmic Elective Surgeries Post-COVID-19

Purpose: As ophthalmic elective surgeries resume amidst the COVID-19 pandemic, protocols for testing patients for SARS-CoV-2 is important due to the transmissibility of the virus. Here, we describe the protocol our institution has implemented for screening asymptomatic patients before proceeding to elective ophthalmic surgery. Methods: A retrospective chart review analyzed the number of elective surgeries, results of SARS-CoV-2 testing, and the effect of a positive result on surgery scheduling. Results: We display the screening protocol our institution used to test for SARS-CoV-2. Through its implementation, we found 2 asymptomatic patients who were positive for SARS-CoV-2 resulting in cancellation of their surgeries.  Conclusion: Because of the possibility of positive COVID-19 status in asymptomatic patients and the risk this poses to patients and staff, we recommend testing all asymptomatic patients for SARS-CoV-2 prior to elective surgeries.

Factors Influencing Postgraduate Career Decisions of Ophthalmology Residents

Objective This study aims to identify factors that influence ophthalmology residents' decision to pursue fellowship training or to practice comprehensive ophthalmology after residency.

Design This is a cross-sectional study.

Methods An anonymous survey was sent to ophthalmology residents in the United States from the graduating class of 2018. The main outcome measure was the decision to seek fellowship training or to practice comprehensive ophthalmology. Information on demographics, residency program characteristics, and factors influencing career choices were collected.

Results The overall response rate was 24.0% (112/467). Among the 112 respondents, 88 (78.6%) matched into subspecialty training. Compared with residents entering comprehensive ophthalmology, there was a greater proportion of Asians (37.5 vs. 8.3%) and a smaller proportion of non-Hispanic whites (47.7 vs. 70.8%, p = 0.029) among residents pursuing fellowship training. Residents pursuing fellowships had fewer children (0.4 vs. 0.8, p = 0.049), had less debt (median debt ≤ $100,000 vs. > $200,000, p = 0.008), had more first-author publications (4.3 vs. 1.2, p< 0.001), decided on their postgraduate career path earlier (median time postgraduate second year [PGY2] versus postgraduate third year [PGY3], p = 0.016), and were more likely to plan to practice in an academic setting (51.1 vs. 29.2%, p< 0.001) and in an urban location (44.3 vs. 12.5%, p = 0.004). In a multiple logistic regression model, factors predictive of fellowship training included a desire to acquire special skills (odds ratio [OR] =4.39; 95% confidence intervals [CI]: 1.70–16.37) and work with new technology (OR = 2.92; 95% CI: 1.16–10.02). Factors that predicted a career in comprehensive ophthalmology were higher levels of educational debt (OR = 0.35; 95% CI: 0.12–0.77), a later timing of postgraduate decision (OR = 0.17; 95% CI: 0.02–0.65), and lifestyle considerations (OR = 0.13; 95% CI: 0.03–0.36). Gender, prestige, or perceived favorable job market was not significant factors.

Conclusion The majority of U.S. ophthalmology residents matched into fellowships. A desire to gain special skills and a desire to work with new technology were major factors influencing residents to seek fellowship training. Lifestyle considerations and educational debt were more important in the decision to choose a comprehensive ophthalmology career. Future research that includes more trainees and programs may minimize the selection bias issues present in this study.

Intraocular Pressure Following Prerandomization Glaucoma Medication Washout in the HORIZON and COMPASS Trials

PURPOSE

To assess the effectiveness of topical ocular hypotensive medications in patients with open-angle glaucoma and to identify factors associated with postwashout intraocular pressure (IOP) elevation.

DESIGN

Secondary analysis of prerandomization data from 2 prospective, multicenter, randomized clinical trials.

METHODS

Fourteen hundred subjects (1,400 eyes, 781 from the HORIZON study of the Hydrus micro-stent and 619 from the COMPASS study of the Cypass micro-stent) with primary open-angle glaucoma who were using 0-4 classes of topical IOP-lowering medication underwent Goldmann applanation tonometry before and after a protocol-defined washout period.

RESULTS

The mean (standard deviation) age was 70.7 (8.0) years and 55.6% were female. The change in IOP following washout for patients using 0 (n = 100), 1 (n = 705), 2 (n = 355), 3 (n = 214), or 4 (n = 26) medications was 0.2 (2.8), 5.7 (3.3), 6.9 (3.7), 8.8 (5.0), and 9.5 (4.1) mm Hg, respectively (P < .001, Kruskal-Wallis test). Postwashout IOP change was similar between the HORIZON and COMPASS cohorts. No difference in postwashout IOP change was detected among individual prostaglandin analogues in patients on monotherapy. A generalized linear model identified the following factors to be associated with greater IOP rise upon medication washout: greater number of glaucoma medications, higher unmedicated IOP, thinner central corneal thickness (CCT), lack of prior selective laser trabeculoplasty (SLT), and male sex.

CONCLUSIONS

Cessation of glaucoma medications results in a dose-dependent IOP increase in treated open-angle glaucoma patients. Two independent clinical trial cohorts exhibit similar levels of IOP elevation upon washout, using standardized methodology to estimate real-world medication effectiveness. Thicker CCT and history of SLT may predict reduced response to IOP lowering medications.

A method to quantify regional axonal transport blockade at the optic nerve head after short term intraocular pressure elevation in mice

Axonal transport blockade is an initial step in retinal ganglion cell (RGC) degeneration in glaucoma and targeting maintenance of normal axonal transport could confer neuroprotection. We present an objective, quantitative method for assessing axonal transport blockade in mouse glaucoma models. Intraocular pressure (IOP) was elevated unilaterally in CD1 mice for 3 days using intracameral microbead injection. Longitudinal sections of optic nerve head (ONH) were immunofluorescently labeled for myelin basic protein (MBP) and amyloid precursor protein (APP), which is transported predominantly orthograde by neurons. The beginning of the myelin transition zone, visualized with the MBP label, was more posterior with elevated IOP, 288.8 ± 40.9 μm, compared to normotensive control eyes, 228.7 ± 32.7 μm (p = 0.030, N = 6 pairs). Glaucomatous regional APP accumulations in retina, prelaminar ONH, unmyelinated ONH, and myelinated optic nerve were identified by objective qualification of pixels with fluorescent intensity greater than the 97.5th percentile value of control eyes (suprathreshold pixels). This method segregated images with APP blockade from those with normal transport of APP. The fraction of suprathreshold pixels was significantly higher following IOP elevation than in normotensive controls in the unmyelinated ONH and myelinated nerve regions (paired analyses, p = 0.02 and 0.003, respectively, N = 12), but not in retina or prelaminar ONH (p = 0.91 and 0.08, respectively). The mean intensity of suprathreshold pixels was also significantly greater in glaucoma than in normotensive controls in prelaminar ONH, unmyelinated ONH and myelinated optic nerve (p = 0.01, 0.01, 0.002, respectively). Using this method, subconjunctival glyceraldehyde, which is known to worsen long-term RGC loss with IOP elevation, also produced greater APP blockade, but not statistically significant compared to glaucoma alone. Systemic losartan, which aids RGC axonal survival in glaucoma, reduced APP blockade, but not statistically significant compared to glaucoma alone. The method provides a short-term assessment of axonal injury for use in initial tests of neuroprotective therapies that may beneficially affect RGC transport in animal models of glaucoma.

ACR Appropriateness Criteria® Chest Pain-Possible Acute Coronary Syndrome

Chest pain is a frequent cause for emergency department visits and inpatient evaluation, with particular concern for acute coronary syndrome as an etiology, since cardiovascular disease is the leading cause of death in the United States. Although history-based, electrocardiographic, and laboratory evaluations have shown promise in identifying coronary artery disease, early accurate diagnosis is paramount and there is an important role for imaging examinations to determine the presence and extent of anatomic coronary abnormality and ischemic physiology, to guide management with regard to optimal medical therapy or revascularization, and ultimately to thereby improve patient outcomes. A summary of the various methods for initial imaging evaluation of suspected acute coronary syndrome is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Aqueous Flow Measured by Fluorophotometry in the Mouse

PURPOSE

A fluorophotometer designed to measure aqueous flow in murine eyes was tested with artificial fluorescein chambers and in live mice with different anesthesia regimens, aqueous flow suppressants, and an anterior chamber cannulation method.

METHODS

Two hours following topical fluorescein application, one group of CD-1 mice was anesthetized with ketamine/xylazine, 2,2,2-tribromoethanol, or ketamine alone. Cornea and anterior chamber fluorescein concentrations were measured periodically for 60 to 90 minutes by fluorophotometric scans to calculate aqueous flow. Later, a subgroup of mice underwent aqueous flow measurement by anterior chamber cannulation. A third group was treated with timolol, dorzolamide, and vehicle in a crossover manner 1 hour prior to fluorophotometric scans.

RESULTS

Aqueous flow with ketamine/xylazine anesthesia (0.09 ± 0.05 μL/min, mean ± SD, n = 24) was slower than with tribromoethanol or ketamine alone (P < 0.001). Timolol reduced aqueous flow from 0.20 ± 0.07 μL/min to 0.07 ± 0.03 μL/min (P = 0.001) under tribromoethanol anesthesia and from 0.14 ± 0.03 μL/min to 0.10 ± 0.02 μL/min (P = 0.004) under ketamine anesthesia but not under ketamine/xylazine anesthesia. Dorzolamide reduced aqueous flow from 0.09 ± 0.03 to 0.06 ± 0.03 μL/min (P = 0.04) under ketamine/xylazine anesthesia. Aqueous flow by anterior chamber cannulation (0.20 ± 0.13 μL/min) was greater (P = 0.05) than by fluorophotometry (0.09 ± 0.07 μL/min).

CONCLUSIONS

A new noninvasive fluorophotometric method detected effects of general anesthesia and known aqueous suppressants on aqueous flow in mice. Aqueous flow measured by fluorophotometry was slower than by cannulation, and was technically easier with less variability. The mouse fluorophotometer is useful for repeated measurements of aqueous flow in the murine eye making crossover and longitudinal studies possible.

Time-Lapse Retinal Ganglion Cell Dendritic Field Degeneration Imaged in Organotypic Retinal Explant Culture

Purpose

To develop an ex vivo organotypic retinal explant culture system suitable for multiple time-point imaging of retinal ganglion cell (RGC) dendritic arbors over a period of 1 week, and capable of detecting dendrite neuroprotection conferred by experimental treatments.

Methods

Thy1-YFP mouse retinas were explanted and maintained in organotypic culture. Retinal ganglion cell dendritic arbors were imaged repeatedly using confocal laser scanning microscopy. Maximal projection z-stacks were traced by two masked investigators and dendritic fields were analyzed for characteristics including branch number, size, and complexity. One group of explants was treated with brain derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) added to the culture media. Changes in individual dendritic fields over time were detected using pair-wise comparison testing.

Results

Retinal ganglion cells in mouse retinal explant culture began to degenerate after 3 days with 52.4% surviving at 7 days. Dendritic field parameters showed minimal change over 8 hours in culture. Intra- and interobserver measurements of dendrite characteristics were strongly correlated (Spearman rank correlations consistently > 0.80). Statistically significant (P < 0.001) dendritic tree degeneration was detected following 7 days in culture including: 40% to 50% decreases in number of branch segments, number of junctions, number of terminal branches, and total branch length. Scholl analyses similarly demonstrated a significant decrease in dendritic field complexity. Treatment of explants with BDNF+CNTF significantly attenuated dendritic field degeneration.

Conclusions

Retinal explant culture of Thy1-YFP tissue provides a useful model for time-lapse imaging of RGC dendritic field degeneration over a course of several days, and is capable of detecting neuroprotective amelioration of dendritic pruning within individual RGCs.

Stem cell therapy for glaucoma: possibilities and practicalities

Glaucoma is a progressive, neurodegenerative, optic neuropathy in which currently available therapies cannot always prevent, and do not reverse, vision loss. Stem cell transplantation may provide a promising new avenue for treating many presently incurable degenerative conditions, including glaucoma. This article will explore the various ways in which transplantation of stem or progenitor cells may be applied for the treatment of glaucoma. We will critically discuss the translational prospects of two cell transplantation-based treatment modalities: neuroprotection and retinal ganglion cell replacement. In addition, we will identify specific questions that need to be addressed and obstacles to overcome on the path to clinical translation, and offer insight into potential strategies for approaching this goal.

Identification of retinal ganglion cell neuroprotection conferred by platelet-derived growth factor through analysis of the mesenchymal stem cell secretome

The development of neuroprotective strategies to attenuate retinal ganglion cell death could lead to novel therapies for chronic optic neuropathies such as glaucoma. Intravitreal transplantation of mesenchymal stem cells slows retinal ganglion cell death in models of optic nerve injury, but the mechanism of action remains unclear. Here we characterized the neuroprotective effects of mesenchymal stem cells and mesenchymal stem cell-derived factors in organotypic retinal explant culture and an in vivo model of ocular hypertensive glaucoma. Co-culture of rat and human bone marrow-derived mesenchymal stem cells with retinal explants increased retinal ganglion cell survival, after 7 days ex vivo, by ∼2-fold and was associated with reduced apoptosis and increased nerve fibre layer and inner plexiform layer thicknesses. These effects were not demonstrated by co-culture with human or mouse fibroblasts. Conditioned media from mesenchymal stem cells conferred neuroprotection, suggesting that the neuroprotection is mediated, at least partly, by secreted factors. We compared the concentrations of 29 factors in human mesenchymal stem cell and fibroblast conditioned media, and identified 11 enriched in the mesenchymal stem cell secretome. Treatment of retinal explants with a cocktail of these factors conferred retinal ganglion cell neuroprotection, with factors from the platelet-derived growth factor family being the most potent. Blockade of platelet-derived growth factor signalling with neutralizing antibody or with small molecule inhibitors of platelet-derived growth factor receptor kinase or downstream phosphatidylinositol 3 kinase eliminated retinal ganglion cell neuroprotection conferred by mesenchymal stem cell co-culture. Intravitreal injection of platelet-derived growth factor -AA or -AB led to profound optic nerve neuroprotection in vivo following experimental induction of elevated intraocular pressure. These data demonstrate that mesenchymal stem cells secrete a number of neuroprotective proteins and suggest that platelet-derived growth factor secretion in particular may play an important role in mesenchymal stem cell-mediated retinal ganglion cell neuroprotection. Furthermore, platelet-derived growth factor may represent an independent target for achieving retinal ganglion cell neuroprotection.

Myocilin mediates myelination in the peripheral nervous system through ErbB2/3 signaling

The glaucoma-associated gene, myocilin, is expressed in ocular and non-ocular tissues including the peripheral nervous system, but its functions in these tissues remain poorly understood. We demonstrate that in sciatic nerve, myocilin is expressed in Schwann cells with high concentrations at the nodes of Ranvier. There, myocilin interacts with gliomedin, neurofascin, and NrCAM, which are essential for node formation and function. Treatment of isolated dorsal root ganglion cultures with myocilin stimulates clustering of the nodal proteins neurofascin and sodium channel Nav1.2. Sciatic nerves of myocilin null mice express reduced levels of several myelin-associated and basal membrane proteins compared with those of wild-type littermates. They also demonstrate reduced myelin sheath thickness and partial disorganization of the nodes. Myocilin signaling through ErbB2/3 receptors may contribute to these observed effects. Myocilin binds to ErbB2/ErbB3, activates these receptors, and affects the downstream PI3K-AKT signaling pathway. These data implicate a role for myocilin in the development and/or maintenance of myelination and nodes of Ranvier in sciatic nerve.

Myocilin stimulates osteogenic differentiation of mesenchymal stem cells through mitogen-activated protein kinase signaling

Myocilin is a secreted glycoprotein that is expressed in ocular and non-ocular tissues. Mutations in the MYOCILIN gene may lead to juvenile- and adult-onset primary open-angle glaucoma. Here we report that myocilin is expressed in bone marrow-derived mesenchymal stem cells (MSCs) and plays a role in their differentiation into osteoblasts in vitro and in osteogenesis in vivo. Expression of myocilin was detected in MSCs derived from mouse, rat, and human bone marrow, with human MSCs exhibiting the highest level of myocilin expression. Expression of myocilin rose during the course of human MSC differentiation into osteoblasts but not into adipocytes, and treatment with exogenous myocilin further enhanced osteogenesis. MSCs derived from Myoc-null mice had a reduced ability to differentiate into the osteoblastic lineage, which was partially rescued by exogenous extracellular myocilin treatment. Myocilin also stimulated osteogenic differentiation of wild-type MSCs, which was associated with activation of the p38, Erk1/2, and JNK MAP kinase signaling pathways as well as up-regulated expression of the osteogenic transcription factors Runx2 and Dlx5. Finally, cortical bone thickness and trabecular volume, as well as the expression level of osteopontin, a known factor of bone remodeling and osteoblast differentiation, were reduced dramatically in the femurs of Myoc-null mice compared with wild-type mice. These data suggest that myocilin should be considered as a target for improving the bone regenerative potential of MSCs and may identify a new role for myocilin in bone formation and/or maintenance in vivo.

Cell transplantation approaches to retinal ganglion cell neuroprotection in glaucoma

Glaucoma is a complex neurodegenerative disease that involves interactions among multiple signaling pathways, ultimately leading to progressive retinal ganglion cell (RGC) death. The development of neuroprotective approaches to glaucoma therapy could preserve vision by modulating these pathologic pathways or by acting directly on RGCs to attenuate cell death and maintain function. Intraocular cell transplantation is being evaluated as one approach to achieve sustained RGC neuroprotection. Unlike traditional pharmacological approaches, transplanted cells might be capable of simultaneously targeting multiple pro-survival pathways via local delivery of secreted factors and/or via modulation of the intraocular microenvironment. Elucidating the mechanisms by which different cell types attenuate RGC death in models of glaucoma may uncover additional novel mechanisms of neuroprotection. In this review, we will discuss the rationale for transplantation-based approaches to neuroprotection for glaucoma and explore the various mechanisms of action proposed to account for RGC neuroprotection achieved by two distinct cell classes that have been studied most extensively for this purpose: glial cells and mesenchymal stem cells.

Abstract 102: FOCUS: Appropriate Use of Cardiac Imaging

Introduction The American College of Cardiology has created a new initiative (FOCUS) to help reduce inappropriate use of clinical imaging in cardiology. In accord with the effort, the Sanger Heart and Vascular Institute (SHVI) has designed a program to enhance appropriate use of cardiac imaging.

Hypothesis: By implementing a quality improvement program to evaluate the appropriateness of cardiac imaging, there will be a 10% improvement in the percentage of studies ordered for appropriate indications and a corresponding decrease in the number of studies ordered for inappropriate indications.

Methods: The initiative utilized an integrated multifaceted approach to quality improvement: 1) Staff / physician education with video teleconferences: Presentations were given at SHVI’s Grand Round, focusing on the appropriate use criteria as outlined in the ACCF/ASE/ASNC documents. An important component was interactive case studies highlighting the principles of appropriate use criteria. 2) Peer review and audits: Each practitioner and site received individual performance feedback. This was a complete analysis which included testing appropriateness as an indication. 3) System support tools: A comprehensive order sheet with check boxes for all appropriate indications was designed. All ordering physicians were asked to use this form for ordering all cardiac imaging studies. For those studies in which the form was not utilized, the imaging technologist attempted to obtain the appropriate information. All information from the forms was entered into a database designed specifically for this study. A baseline survey of 30 consecutive studies was selected for analysis from each echocardiography and cardiac nuclear imaging site within SHVI for a total of 360 studies. The ongoing post intervention survey conducts a monthly review of 25% of all studies per site.

Results: At baseline, 77% of transthoracic echocardiographic studies were ordered for appropriate indications. Post intervention there was significant improvement: 91% (p<0.0013) of studies were categorized as appropriate and 1% of studies categorized as inappropriate (14% improvement in each). Of the remaining studies, 9% could not be categorized. With regards to stress cardiac imaging, 71% of studies were ordered for appropriate indications at baseline. Post intervention, there was significant improvement: 94% (p<0.0008) of studies categorized as appropriate (23% improvement), 16% categorized as inappropriate, and 6% could not be categorized.

Conclusion: Although there is limited data on a national basis, published literature would suggest 70-80% appropriate use of cardiac imaging as a baseline benchmark. The results of this initiative demonstrated a statistically significant benefit in the appropriate use of cardiac imaging for SHVI from this baseline. The data gathering and database capabilities established during this initiative will allow quarterly reviews to providers, which will help ensure continued compliance with the guidelines.