Clinical Focus
- Ophthalmology
- Cataract
- Cataract Surgery
- Laser Cataract Surgery
- Femtosecond Laser
Academic Appointments
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Clinical Professor, Ophthalmology
Administrative Appointments
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Ophthalmology Delegate, Stanford OR Committee (2008 - Present)
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Director, Cataract Surgery Service (2010 - Present)
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Clinic Chief, Department of Ophthalmology (2007 - 2022)
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Director, Byers Eye Surgery Center at Stanford (2012 - Present)
Professional Education
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Internship: UCSF Health St Mary's Hospital (2002) CA
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Medical Education: Yale School Of Medicine (2001) CT
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Residency: Stanford University Ophthalmology Residency (2005) CA
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Board Certification: American Board of Ophthalmology, Ophthalmology (2006)
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MD, Yale University (2001)
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PhD, Yale University, Neuroscience (1999)
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BA, Amherst College, Neuroscience (1991)
Community and International Work
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US Eye Care and Cataract Surgery, Fiji
Partnering Organization(s)
SMA
Location
International
Ongoing Project
No
Opportunities for Student Involvement
No
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International Cataract Surgery, Guatemala
Partnering Organization(s)
SEE International
Location
International
Ongoing Project
No
Opportunities for Student Involvement
No
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Thimphu Hospital, Bhutan
Topic
International Ophthalmology Instruction
Partnering Organization(s)
Health Volunteers Overseas
Populations Served
Bhutan
Location
International
Ongoing Project
No
Opportunities for Student Involvement
No
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Arbor Clinic
Topic
Ophthalmology
Populations Served
under-served
Location
Bay Area
Ongoing Project
Yes
Opportunities for Student Involvement
No
Current Research and Scholarly Interests
Multicenter Catalys Consortium Trial - To compare femtosecond laser assisted cataract surgery with conventional cataract surgery
2024-25 Courses
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Independent Studies (5)
- Directed Reading in Ophthalmology
OPHT 299 (Aut, Win, Spr, Sum) - Early Clinical Experience in Ophthalmology
OPHT 280 (Aut, Win, Spr, Sum) - Graduate Research
OPHT 399 (Aut, Win, Spr, Sum) - Medical Scholars Research
OPHT 370 (Aut, Win, Spr, Sum) - Undergraduate Research
OPHT 199 (Aut, Win, Spr, Sum)
- Directed Reading in Ophthalmology
All Publications
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Using Electronic Health Record Data to Determine the Safety of Aqueous Humor Liquid Biopsies for Molecular Analyses.
Ophthalmology science
2024; 4 (5): 100517
Abstract
Knowing the surgical safety of anterior chamber liquid biopsies will support the increased use of proteomics and other molecular analyses to better understand disease mechanisms and therapeutic responses in patients and clinical trials. Manual review of operative notes from different surgeons and procedures in electronic health records (EHRs) is cumbersome, but free-text software tools could facilitate efficient searches.Retrospective case series.A total of 1418 aqueous humor liquid biopsies from patients undergoing intraocular surgery.Free-text EHR searches were performed using the Stanford Research Repository cohort discovery tool to identify complications associated with anterior chamber paracentesis and subsequent endophthalmitis. Complications of the surgery unrelated to the biopsy were not reviewed.Biopsy-associated intraoperative complications and endophthalmitis.A total of 1418 aqueous humor liquid biopsies were performed by 17 experienced surgeons. EHR free-text searches were 100% error-free for surgical complications, >99% for endophthalmitis (<1% false positive), and >93.6% for anesthesia type, requiring manual review for only a limited number of cases. More than 85% of cases were performed under local anesthesia without ocular muscle akinesia. Although the most common indication was cataract (50.1%), other diagnoses included glaucoma, diabetic retinopathy, uveitis, age-related macular degeneration, endophthalmitis, retinitis pigmentosa, and uveal melanoma. A 50- to 100-μL sample was collected in all cases using either a 30-gauge needle or a blunt cannula via a paracentesis. The median follow-up was >7 months. There was only one minor complication (0.07%) identified: a case of a small tear in Descemet membrane without long-term sequelae. No other complications occurred, including other corneal injuries, lens or iris trauma, hyphema, or suprachoroidal hemorrhage. There was no case of postoperative endophthalmitis.Anterior chamber liquid biopsy during intraocular surgery is a safe procedure and may be considered for large-scale collection of aqueous humor samples for molecular analyses. Free-text EHR searches are an efficient approach to reviewing intraoperative procedures.Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
View details for DOI 10.1016/j.xops.2024.100517
View details for PubMedID 38881613
View details for PubMedCentralID PMC11179400
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Liquid-biopsy proteomics combined with AI identifies cellular drivers of eye aging and disease in vivo.
Cell
2023
Abstract
Single-cell analysis in living humans is essential for understanding disease mechanisms, but it is impractical in non-regenerative organs, such as the eye and brain, because tissue biopsies would cause serious damage. We resolve this problem by integrating proteomics of liquid biopsies with single-cell transcriptomics from all known ocular cell types to trace the cellular origin of 5,953 proteins detected in the aqueous humor. We identified hundreds of cell-specific protein markers, including for individual retinal cell types. Surprisingly, our results reveal that retinal degeneration occurs in Parkinson's disease, and the cells driving diabetic retinopathy switch with disease stage. Finally, we developed artificial intelligence (AI) models to assess individual cellular aging and found that many eye diseases not associated with chronological age undergo accelerated molecular aging of disease-specific cell types. Our approach, which can be applied to other organ systems, has the potential to transform molecular diagnostics and prognostics while uncovering new cellular disease and aging mechanisms.
View details for DOI 10.1016/j.cell.2023.09.012
View details for PubMedID 37863056
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Biobanking of Human Aqueous and Vitreous Liquid Biopsies for Molecular Analyses.
Journal of visualized experiments : JoVE
2023
Abstract
A critical challenge in translational research is establishing a viable and efficient interface between patient care in the operating room (OR) and the research laboratory. Here, we developed a protocol for acquiring high-quality liquid biopsies for molecular analyses from the aqueous humor and the vitreous from patients undergoing eye surgery. In this workflow, a Mobile Operating Room Lab Interface (MORLI) cart equipped with a computer, a barcode scanner, and lab instruments, including onboard cold storage, is used to obtain and archive human biological samples. A web-based data privacy-compliant database enables annotating each sample over its lifetime, and a cartesian coordinate system allows tracking each barcoded specimen in storage, enabling quick and accurate retrieval of samples for downstream analyses. Molecular characterization of human tissue samples not only serves as a diagnostic tool (e.g., to distinguish between infectious endophthalmitis and other non-infectious intraocular inflammation) but also represents an important component of translational research, allowing the identification of new drug targets, development of new diagnostic tools, and personalized therapeutics.
View details for DOI 10.3791/65804
View details for PubMedID 37747194
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Immunoprofiling of Nonarteritic Anterior Ischemic Optic Neuropathy.
Translational vision science & technology
2021; 10 (8): 17
Abstract
Purpose: Nonarteritic anterior ischemic optic neuropathy (NAION) is a common acute optic neuropathy in those older than 50 years. There is no blood diagnostic test or efficient treatment for NAION. We investigated the suitability of blood inflammatory proteins as biomarkers and therapeutic targets of NAION.Methods: We conducted an exploratory, cross-sectional case-control study including 18 patients with NAION (n = 5 acute, and n = 13 chronic) and 9 controls. NAION was confirmed by clinical examination and optical coherence tomography. Subjects underwent peripheral blood collection; plasma was isolated within 2 hours and analyzed using a 76-plex array of cytokines, chemokines, and growth factors.Results: In acute NAION, there was increased peripapillary retinal thickness on optical coherence tomography consistent with optic disc edema. Plasma profiling revealed dramatic changes in inflammatory proteins in NAION. Statistical analysis generated a list of 20 top-ranked molecules in NAION, with 15% overlap in acute and chronic NAION. Principal component analysis, hierarchical clustering, and Spearman correlation generally segregated controls, acute and chronic NAION, with some overlap. Longitudinal data from one patient demonstrated an evolving inflammatory pattern from acute to chronic NAION. In acute NAION, Eotaxin-3, MCP-2, TPO, and TRAIL were the top biomarker candidates. In chronic NAION, IL-1alpha and CXCL10 emerged as the strongest therapeutic targets.Conclusions: Post-NAION inflammation occurs in both acute and chronic NAION. Statistical analysis of plasma profile changes generated a list of 20 potential biomarker and therapeutic targets of NAION.Translational Relevance: We identified blood molecular targets to improve NAION diagnosis and treatment.
View details for DOI 10.1167/tvst.10.8.17
View details for PubMedID 34264294
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Immunoprofiling of Nonarteritic Anterior Ischemic Optic Neuropathy
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2021
View details for Web of Science ID 000690761400568
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Multimodal Imaging of Posterior Dislocation of Crystalline Lens Nucleus following Vitrectomy.
Journal of ophthalmic & vision research
2015; 10 (2): 197-199
View details for DOI 10.4103/2008-322X.163785
View details for PubMedID 26425326
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Comparison of One-Day Versus One-Hour Application of Topical Gatifloxacin in Eliminating Conjunctival Bacterial Flora
111th Annual Meeting of the American-Academy-of-Ophthalmology
ELSEVIER SCIENCE INC. 2008: 2013–16
Abstract
To compare efficacies of 1-day, 1-hour, and combined 1-day/1-hour preoperative topical gatifloxacin in eliminating conjunctival bacterial flora.Prospective, comparative case series.Sixty patients (120 eyes) scheduled to undergo anterior segment intraocular surgery at Stanford University Medical Center.Cultures were collected from the palpebral conjunctival sac at baseline and after 1 day (4 doses), 1 hour (3 doses), and 1 day/1 hour (7 doses) of gatifloxacin use.Incidence of positive bacterial samples collected pre- and post-antibiotic treatment and number of colony forming units (CFUs).SeptiChek (Becton Dickinson, Franklin Lakes, NJ) positive cultures significantly decreased from 67% growth at baseline to 28% (P<0.0001) after 1 day and from 60% at baseline to 37% (P = 0.018) after 1 hour of gatifloxacin use. Reductions of 44% growth at baseline to 12% (P = 0.0001) after 1 day and 32% at baseline to 13% (P = 0.029) after 1 hour of gatifloxacin use were observed on blood agar. Surgical eyes that received both 1-day and 1-hour preoperative gatifloxacin had reductions from 67% growth at baseline to 18% posttreatment (P<0.0001) and 45% at baseline to 7% posttreatment (P<0.0001) on SeptiChek and blood agar media, respectively. In addition to a lower frequency of positive cultures, a significantly lower CFU count was found after 1-day (P = 0.004) and 1-hour (P = 0.049) gatifloxacin use compared with pretreatment levels. Combined 1-day/1-hour doses of gatifloxacin were associated with a greater reduction in CFUs (P = 0.001) when compared with 1-hour treatment alone.Both 1-hour and 1-day topical gatifloxacin use are effective in reducing the frequency of conjunctival bacterial growth and the overall bacterial load as measured by CFUs, relative to baseline. Although a 1-hour pretreatment is associated with a reduction in bacterial growth, the combination of 1-day and 1-hour preoperative gatifloxacin dosing results in an even lower overall bacterial load, suggesting that the latter might be the preferred preoperative regimen for eyes undergoing anterior segment surgery.
View details for DOI 10.1016/j.ophtha.2008.06.024
View details for PubMedID 18708260
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Prospective comparison of topical moxifloxacin in eliminating conjunctival bacterial flora following a one-day or one-hour application
Annual Meeting of the Association-for-Research-in-Vision-and-Ophthalmology
MARY ANN LIEBERT INC. 2008: 427–31
Abstract
The aim of this study was to compare the efficacy of a 1-hour(h) versus 1-day application of topical moxifloxacin in eliminating conjunctival bacterial flora.In this prospective, nonrandomized, controlled trial, the surgical eyes of 60 patients scheduled for intraocular surgery received topical moxifloxacin four times a day, starting 1 day prior to surgery and three additional applications at 5-minute intervals 1 h before surgery. The nonsurgical eye of each patient only received three applications of the same antibiotic at 5-minute intervals 1 h before surgery. Conjunctival cultures were obtained at baseline and after antibiotic application.Prior to antibiotic application, 80% of surgical eyes and 70% of nonsurgical eyes had positive cultures. Following the 1-day application, significantly fewer eyes (40%) had positive cultures (P < 0.0001), with a further reduction to 32% with three additional doses 1 h prior to surgery. In the nonsurgical eye, the decrease in the percentage of positive cultures, from 55% to 53% following the three applications 1 h prior to surgery, was not significant (P > 0.9999). The 1-day application was associated with significantly fewer positive cultures, compared to the 1-h group (P = 0.0267).The one-day application of moxifloxacin resulted in significantly fewer positive conjunctival cultures, compared with a 1-h application.
View details for DOI 10.1089/jop.2008.0018
View details for PubMedID 18665815
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CustomVue laser in situ keratomileusis treatment after previous keratorefractive surgery
JOURNAL OF CATARACT AND REFRACTIVE SURGERY
2006; 32 (5): 795-798
Abstract
To evaluate the efficacy, predictability, and safety of Visx CustomVue wavefront-guided enhancement after previous keratorefractive surgery.Stanford University Eye Laser Center, Stanford, California, USA.A retrospective analysis was used to evaluate wavefront-guided enhancement in a preliminary set of 120 eyes of 102 patients. All eyes had previous keratorefractive surgery (photorefractive keratoplasty [PRK] in 1 eye, laser in situ keratomileusis [LASIK] in 119 eyes); the prekeratorefractive surgery spherical equivalent (SE) refraction ranged from -1.25 diopters (D) to -7.00 D. Primary outcome variables including uncorrected visual acuity (UCVA), manifest refraction, and complications were evaluated at 1 and 3 months.At 1 month, the mean pre-enhancement SE was reduced from -0.91 D +/- 0.40 (SD) (range -2.375 to -0.125 D) to -0.13 +/- 0.33 D (range -1.25 to 0.75 D) with 91% of eyes within +/-0.5 D of emmetropia and 100% within +/-1.0 D. All eyes showed equal or improved UCVA (range 20/15 to 20/30) with 20/20 or better in 84 of 91 eyes. At 3 months, the mean was -0.20 +/- 0.32 D (range -0.75 to 0.75 D) with 100% of eyes within +/-0.75 D of emmetropia. All eyes showed equal or improved UCVA (range 20/15 to 20/30) with 20/20 or better in 74 of 84 eyes. Higher-order wavefront aberration analysis showed that the mean root-mean-square error was reduced from 0.39 +/- 0.14 microm (range 0.16 to 0.86 microm) to 0.34 +/- 0.12 microm (range 0.12 to 0.78 microm). Coma was reduced from 0.22 +/- 0.13 microm (range 0.02 to 0.71 microm) to 0.16 +/- 0.11 microm (range 0.01 to 0.62 microm), and trefoil was reduced from 0.16 +/- 0.09 microm (range 0.01 to 0.62 microm) to 0.11 +/- 0.07 microm (range 0.01 to 0.27 microm). Spherical aberration was unchanged from 0.14 +/- 0.14 microm (range -0.18 to 0.59 microm) to 0.14 +/- 0.14 microm (range -0.16 to 0.5 microm).Preliminary data show that Visx CustomVue wavefront-guided enhancement after keratorefractive surgery is an effective, predictable, and safe procedure.
View details for DOI 10.1016/j.jcrs.2006.01.081
View details for PubMedID 16765797
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Differential distribution of ionotropic glutamate receptor subunits in the rat olfactory bulb
JOURNAL OF COMPARATIVE NEUROLOGY
1999; 405 (2): 233-246
Abstract
The subcellular localization of ionotropic glutamate receptor (GluR) subunits was examined with light and electron microscopy in the rat olfactory bulb by using antibodies to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor subunits: GluR1, GluR2/3, and GluR4; and kainate (KA) receptor subunits: GluR5/6/7. Immunoreactivity to GluR1 was heavy in the glomerular layer, moderate in the external plexiform layer, and localized to periglomerular somata and dendrites, short axon somata and dendrites, mitral cell somata, and mitral/tufted dendrites. GluR2/3 immunoreactivity was heavy in the external plexiform and glomerular layers and localized to periglomerular somata and dendrites, mitral cell somata, mitral/tufted dendrites, granule cell somata, and olfactory nerve-associated glia. GluR4 immunoreactivity showed heavy staining in the external plexiform and olfactory nerve layers with localization to mitral cells, mitral/tufted dendritic processes, and olfactory nerve glial processes. GluR5/6/7 immunoreactivity was heavy in the external plexiform layer, moderate in the olfactory nerve and glomerular layers, and localized to granule cells, mitral cells, and mitral/tufted dendritic processes. Ultrastructural immunolabeling for all antibodies examined showed immunoreactivity in the postsynaptic membrane and densities, adjacent dendritic cytoplasm, and somatic cytoplasm. These data demonstrate a highly specific laminar, cellular, and subcellular distribution of ionotropic GluR subunits within the primary afferent and local synaptic circuits of the olfactory bulb. The results are consistent with the notion that the different roles subserved by glutamate in the olfactory bulb are actuated, in part, by a differential distribution of GluR subunits.
View details for Web of Science ID 000078411900007
View details for PubMedID 10023812