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Dr. Koo is an ophthalmologist specializing in pediatric ophthalmology, retinopathy of prematurity (ROP) and adult strabismus. She received her ophthalmology training at UC San Francisco and then her fellowship training in pediatric ophthalmology and adult strabismus at Boston Children's Hospital affiliated with Harvard Medical School. She has been board certified by the American Board of Ophthalmology since 2016. Her practice reflects her clinical interests in pediatric ophthalmology (strabismus, amblyopia, pediatric cataracts, and ROP) and in adult strabismus.

She utilizes botox in management of adult and pediatric strabismus. She also uses hidden adjustable sutures in children and adults to optimize alignment of eyes with surgery. Muscles can be adjusted up to 10 days after surgery.
She also has an interest in teaching residents and improving surgical training.

Clinical Focus

  • Ophthalmology

Academic Appointments

Honors & Awards

  • Farley Award, Boston Children's Hospital (2016)
  • House Officer Award for Clinical Research, Boston Children?s Hospital (2016)
  • Heed Fellowship Award, Heed Ophthalmic Foundation (2015)
  • Vice President of Cordes Society, UC San Francisco Ophthalmology Alumni Society (2014)
  • Member of Board of Trustees, California Academy of Eye Physicians and Surgeons (CAEPS) (2013)
  • Emergency Medicine Intern of the Year Award, Scripps Mercy Hospital, San Diego (2012)
  • Mercy Style of Care Award, Scripps Mercy Hospital (2012)
  • Alpha Omega Alpha Honor Medical Society, Alpha Omega Alpha Honor Medical Society (2011)
  • Association of Pathology Chairs Award, University of Florida College of Medicine (2009)

Boards, Advisory Committees, Professional Organizations

  • Member, American Association for Pediatric Ophthalmology and Strabismus (2015 - Present)
  • Member, American Academy of Ophthalmology (2012 - Present)

Professional Education

  • Fellowship: Boston Children's Hospital (2016) MA
  • Internship: Scripps Mercy Hospital Transitional Internship (2012) CA
  • Board Certification: American Board of Ophthalmology, Ophthalmology (2016)
  • Residency: University of California at San Francisco School of Medicine (2015) CA
  • Fellowship, Boston Children's Hospital, Harvard Medical school, Pediatric Ophthalmology (2016)
  • Residency, UC San Francisco, Ophthalmology residency (2015)
  • Internship, Scripps Mercy Hospital, Transitional Intern year (2012)
  • Medical Education: University of Florida, College of Medicine (2011) FL
  • MD, University of Florida College of Medicine (2011)
  • BS, University of Florida (2007)


All Publications

  • Outcomes After Corneal Crosslinking for Keratoconus in Children and Young Adults. Cornea Saleh, S., Koo, E. B., Lambert, S. R., Manche, E. E. 2021


    PURPOSE: The aim of this study was to assess the effect of corneal crosslinking on vision and keratometry in children and young adults with progressive keratoconus.METHODS: A retrospective medical records review of patients aged 22 years or younger with keratoconus who underwent corneal crosslinking between January 2013 and November 2019 at Byers Eye Institute at Stanford University was conducted. Outcome measures included logarithm of the Minimum Angle of Resolution corrected distance visual acuity (CDVA); keratometry, including maximum keratometry (Kmax); pachymetry; and total wavefront aberration. Measurements were taken at baseline and at 12 and 24 months postoperatively.RESULTS: Fifty-seven eyes of 49 patients aged 12 to 22 years were assessed. The mean preoperative CDVA was logarithm of the Minimum Angle of Resolution 0.38 ▒ 0.32 (20/48), with a mean postoperative CDVA of 0.29 ▒ 0.31 (20/39) and 0.31 ▒ 0.31 (20/41) at 12 and 24 months postoperatively, respectively. Compared with preoperative mean Kmax, there was an improvement of -0.8 diopters (D) to a mean postoperative Kmax of 59.1 ▒ 9.1 D at 12 months and -1.3 D to 59.7 ▒ 8.8 D at 24 months. Subanalysis excluding the second eye of patients who underwent bilateral crosslinking showed similar results. Linear mixed modeling showed significant improvement in Kmax at both 12 and 24 months postoperatively. Minimum central corneal thickness initially decreased but stabilized at 24 months after crosslinking. Total wavefront aberration remained stable.CONCLUSIONS: Corneal crosslinking stabilizes, and in some cases improves, visual and corneal parameters in pediatric and young adult patients with keratoconus. The procedure is safe and well-tolerated and may prevent keratoconus progression in young patients.

    View details for DOI 10.1097/ICO.0000000000002730

    View details for PubMedID 33859086

  • Prenatal and postnatal inflammation-related risk factors for retinopathy of prematurity JOURNAL OF PERINATOLOGY Goldstein, G. P., Leonard, S. A., Kan, P., Koo, E. B., Lee, H. C., Carmichael, S. L. 2019; 39 (7): 964?73
  • Prenatal and postnatal inflammation-related risk factors for retinopathy of prematurity. Journal of perinatology : official journal of the California Perinatal Association Goldstein, G. P., Leonard, S. A., Kan, P. n., Koo, E. B., Lee, H. C., Carmichael, S. L. 2019


    To evaluate the relationship between prenatal and postnatal inflammation-related risk factors and severe retinopathy of prematurity (ROP).The study included infants born <30 weeks in California from 2007 to 2011. Multivariable log-binomial regression was used to assess the association between prenatal and postnatal inflammation-related exposures and severe ROP, defined as stage 3-5 or surgery for ROP.Of 14,816 infants, 10.8% developed severe ROP. Though prenatal inflammation-related risk factors were initially associated with severe ROP, after accounting for the effect of these risk factors on gestational age at birth through mediation analysis, the association was non-significant (P?=?0.6). Postnatal factors associated with severe ROP included prolonged oxygen exposure, sepsis, intraventricular hemorrhage, and necrotizing enterocolitis.Postnatal inflammation-related factors were associated with severe ROP more strongly than prenatal factors. The association between prenatal inflammation-related factors and ROP was explained by earlier gestational age in infants exposed to prenatal inflammation.

    View details for PubMedID 30932029

  • Review of Ocular Manifestations of Joubert Syndrome. Genes Wang, S. F., Kowal, T. J., Ning, K., Koo, E. B., Wu, A. Y., Mahajan, V. B., Sun, Y. 2018; 9 (12)


    Joubert syndrome is a group of rare disorders that stem from defects in a sensory organelle, the primary cilia. Affected patients often present with disorders involving multiple organ systems, including the brain, eyes, and kidneys. Common symptoms include breathing abnormalities, mental developmental delays, loss of voluntary muscle coordination, and abnormal eye movements, with a diagnostic "molar tooth" sign observed by magnetic resonance imaging (MRI) of the midbrain. We reviewed the ocular phenotypes that can be found in patients with Joubert syndrome. Ocular motor apraxia is the most frequent (80% of patients), followed by strabismus (74%) and nystagmus (72%). A minority of patients also present with ptosis (43%), chorioretinal coloboma (30%), and optic nerve atrophy (22%). Although mutations in 34 genes have been found to be associated with Joubert syndrome, retinal degeneration has been reported in only 38% of patients. Mutations in AHI1 and CEP290, genes critical to primary cilia function, have been linked to retinal degeneration. In conclusion, Joubert syndrome is a rare pleiotropic group of disorders with variable ocular presentations.

    View details for PubMedID 30518138

  • Incidence of Cytomegalovirus-Related Ocular Disease in Pediatric Patients Mercado, C., Koo, E. B. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2018
  • Global Practice Patterns in the Management of Infantile Cataracts. Eye & contact lens Koo, E. B., VanderVeen, D. K., Lambert, S. R. 2018


    OBJECTIVES: Surveys are an important tool to assess the impact of research on physicians' approach to patient care. This survey was conducted to assess current practice patterns in the management of infantile cataracts in light of the findings of the Infant Aphakia Treatment Study.METHODS: Pediatric ophthalmologists were emailed a link to the survey using newsletters from American Association of Pediatric Ophthalmology and Strabismus, World Society of Pediatric Ophthalmology and Strabismus, and the Pediatric Listserv. The 17-question survey was anonymous and active during July to August 2016.RESULTS: One hundred twenty-five respondents (North America, 65%; Asia, 12%; Europe, 9%; and other, 14%) reported operating on pediatric cataracts. Most practice in a university setting (55%). There was a strong consensus that unilateral cataract surgery should be performed between ages 4 to 6 weeks and aphakic contact lenses should be used to optically correct their eyes, particularly in children ?6 months of age. For bilateral cataracts, there was a trend for surgeons to perform cataract surgery at an older age than unilateral cataract surgery. Surgeons who performed less than 5 versus greater than 20 pediatric cataract surgeries/year were more likely to use aphakic contact lenses in children undergoing cataract surgery more than 6 months of age (62% vs. 35%, P=0.04). Most respondents (73%) indicated that the Infant Aphakia Treatment Study had changed how they manage unilateral congenital cataracts.CONCLUSION: Most pediatric cataract surgeons perform congenital cataract surgery between ages 4 to 6 weeks and use aphakic contact lenses for initial optical correction in infants less than 6 months. Surgeons have equal preference for intraocular lenses and contact lenses in infants more than 6 months of age.

    View details for PubMedID 29369235

  • Treatment of Amblyopia and Amblyopia Risk Factors Based on Current Evidence SEMINARS IN OPHTHALMOLOGY Koo, E. B., Gilbert, A. L., VanderVeen, D. K. 2017; 32 (1): 1-7
  • Effects of Glaucoma Tube Surgery on Corneal Endothelial Cells: A Review. Eye & contact lens Koo, E. B., Hou, J., Keenan, J. D., Stamper, R. L., Jeng, B. H., Han, Y. 2016; 42 (4): 221-224


    The etiology of corneal decompensation after aqueous shunt implantation remains poorly understood. With the use of anterior segment optical coherence tomography and specular microscopy, the relationship of these implants to the surrounding tissues can be investigated over time. This article will review the current knowledge pertaining to endothelial cell loss related to glaucoma and surgery and highlight possible causes that have been proposed for endothelial cell loss after aqueous shunt implantation.

    View details for DOI 10.1097/ICL.0000000000000171

    View details for PubMedID 26222096

  • Treatment of Amblyopia and Amblyopia Risk Factors Based on Current Evidence. Seminars in ophthalmology Koo, E. B., Gilbert, A. L., VanderVeen, D. K. 2016: 1?7


    Amblyopia is a leading cause of low vision and warrants timely management during childhood. We performed a literature review of the management of amblyopia and potential risk factors for amblyopia.Literature review of the management of amblyopia and risk factors for amblyopia.Common amblyopia risk factors include anisometropic or high refractive error, strabismus, cataract, and ptosis. Often a conservative approach with spectacles is enough to prevent amblyopia. However, surgery may be necessary to clear the visual axis or align the eyes.Amblyopia risk factors should be managed early. Though amblyopia treatment is more likely to be successful at a younger age, those who are older but treatment-na´ve may still respond to treatment. Promoting binocular or dichoptic experiences may be the future direction of amblyopia management.

    View details for DOI 10.1080/08820538.2016.1228408

    View details for PubMedID 27748640

  • Evaluation and Management of Acute Acquired Comitant Esotropia in Children. Seminars in ophthalmology Gilbert, A. L., Koo, E. B., Heidary, G. n. 2016: 1?6


    Acute acquired comitant esotropia (AACE) is characterized by a sudden-onset eye misalignment with an equal angle of deviation in all fields of gaze. This form of esotropia is distinct from common forms of childhood esotropia, such as infantile esotropia and accommodative esotropia, in the rapid tempo and typically later timing of onset; further, AACE is distinct from restrictive or paretic strabismus, which usually results in an incomitant angle of deviation that varies with the direction of gaze. The underlying etiologies for AACE are broad but, in some cases, it may be associated with significant neurologic disease. Therefore, the purpose of this article is to examine and summarize the current literature on AACE to provide a framework for the evaluation and management of this form of acquired strabismus.

    View details for DOI 10.1080/08820538.2016.1228398

    View details for PubMedID 27726470

  • An adolescent with a swollen nerve. JAMA ophthalmology Koo, E., de Alba Campomanes, A. G. 2015; 133 (1): 97-98

    View details for DOI 10.1001/jamaophthalmol.2014.4461

    View details for PubMedID 25569312

  • Effect of Glaucoma Tube Shunt Parameters on Cornea Endothelial Cells in Patients With Ahmed Valve Implants CORNEA Koo, E. B., Hou, J., Han, Y., Keenan, J. D., Stamper, R. L., Jeng, B. H. 2015; 34 (1): 37-41


    The aim of this study was to assess the effect of various tube parameters on corneal endothelial cell density (ECD) after insertion of Ahmed valves.Thirty-nine eyes of 33 patients with previous superotemporal (ST) Ahmed valve implantation and 20 eyes of 13 participants with previous uncomplicated phacoemulsification and intraocular lens implantation but no history of glaucoma surgery were evaluated. Various tube parameters were measured with anterior segment optical coherence tomography. ST, central, and inferonasal (IN) ECD and pachymetry were measured. Endothelial cell loss and corneal thickness in the ST cornea was compared with those in the IN cornea.The mean age of the operated patients was 58 ▒ 22 years, and the mean time since glaucoma surgery was 2.5 ▒ 2.6 years. Thirty-two of the 39 study eyes were pseudophakic. The ECD was significantly lower in the ST endothelium than in the IN endothelium in eyes with glaucoma tube surgery (P < 0.001), although this relative reduction in ST ECD was not greater than that seen in pseudophakic control eyes (P = 0.16). In univariate analysis, tube angle relative to the cornea and distance from the tip of the tube to the cornea were significant risk factors for decreased ST endothelial cell loss when assessed relative to the IN ECD (P = 0.01 and P = 0.02, respectively). In multivariate analysis, only the distance of the tube tip to the cornea remained significantly associated with ST endothelial cell loss.Although this was a retrospective study with inherent limitations, tubes that are closer to the cornea seem to lead to increased loss of adjacent endothelial cells.

    View details for Web of Science ID 000345924700011

    View details for PubMedID 25393097

  • Macular xanthophylls, lipoprotein-related genes, and age-related macular degeneration AMERICAN JOURNAL OF CLINICAL NUTRITION Koo, E., Neuringer, M., SanGiovanni, J. P. 2014; 100 (1): 336S-346S


    Plant-based macular xanthophylls (MXs; lutein and zeaxanthin) and the lutein metabolite meso-zeaxanthin are the major constituents of macular pigment, a compound concentrated in retinal areas that are responsible for fine-feature visual sensation. There is an unmet need to examine the genetics of factors influencing regulatory mechanisms and metabolic fates of these 3 MXs because they are linked to processes implicated in the pathogenesis of age-related macular degeneration (AMD). In this work we provide an overview of evidence supporting a molecular basis for AMD-MX associations as they may relate to DNA sequence variation in AMD- and lipoprotein-related genes. We recognize a number of emerging research opportunities, barriers, knowledge gaps, and tools offering promise for meaningful investigation and inference in the field. Overviews on AMD- and high-density lipoprotein (HDL)-related genes encoding receptors, transporters, and enzymes affecting or affected by MXs are followed with information on localization of products from these genes to retinal cell types manifesting AMD-related pathophysiology. Evidence on the relation of each gene or gene product with retinal MX response to nutrient intake is discussed. This information is followed by a review of results from mechanistic studies testing gene-disease relations. We then present findings on relations of AMD with DNA sequence variants in MX-associated genes. Our conclusion is that AMD-associated DNA variants that influence the actions and metabolic fates of HDL system constituents should be examined further for concomitant influence on MX absorption, retinal tissue responses to MX intake, and the capacity to modify MX-associated factors and processes implicated in AMD pathogenesis.

    View details for DOI 10.3945/ajcn.113.071563

    View details for PubMedID 24829491

  • Ten-Year Incidence Rates of Age-Related Cataract in the Age-Related Eye Disease Study (AREDS): AREDS Report No. 33 OPHTHALMIC EPIDEMIOLOGY Koo, E., Chang, J. R., Agron, E., Clemons, T. E., Sperduto, R. D., Ferris, F. L., Chew, E. Y. 2013; 20 (2): 71-81


    To investigate the long-term incidence of age-related cataract and cataract surgery in the Age-Related Eye Disease Study (AREDS) cohort.Baseline and annual lens photographs of participants, aged 55-80 years, were graded centrally for nuclear, cortical, and posterior subcapsular (PSC) lens opacities using the AREDS System for Classifying Cataracts. Progression from a baseline status of no or mild lens opacity to at least moderate severity was analyzed and cumulative incidence estimated rates were calculated for each lens opacity type and cataract surgery stratified by age, sex, race, age-related macular degeneration category, multivitamin (Centrum) use and history of diabetes.The ten-year cumulative incidence was 43.6% for any cataract, 23.1% for nuclear cataract, 22.0% for cortical cataract, 13.1% for PSC cataract, and 26.8% for cataract surgery. The 5- and 10-year incidence rates of all cataract types and cataract surgery were significantly higher with increasing age. Females had a higher incidence of any, nuclear and cortical cataract and cataract surgery (p?=?0.02-0.05). Incidence of cortical cataract was higher in non-white participants (p?=?0.001).These results are largely consistent with the results of previous observational studies. Long-term incidence rates of type-specific cataract can be useful in designing clinical studies of age-related cataract.

    View details for DOI 10.3109/09286586.2012.759598

    View details for Web of Science ID 000316418400001

    View details for PubMedID 23510310



    To evaluate the safety and preliminary efficacy of intravitreal ranibizumab for nonneovascular idiopathic macular telangiectasia Type 2.Single-center, open-label Phase II clinical trial enrolling five participants with bilateral nonneovascular idiopathic macular telangiectasia Type 2. Intravitreal ranibizumab (0.5 mg) was administered every 4 weeks in the study eye for 12 months with the contralateral eye observed. Outcome measures included changes in best-corrected visual acuity, area of late-phase leakage on fluorescein angiography, and retinal thickness on optical coherence tomography.The study treatment was well tolerated and associated with few adverse events. Change in best-corrected visual acuity at 12 months was not significantly different between treated study eyes (0.0 ▒ 7.5 letters) and control fellow eyes (+2.2 ▒ 1.9 letters). However, decreases in the area of late-phase fluorescein angiography leakage (-33 ▒ 20% for study eyes, +1 ▒ 8% for fellow eyes) and in optical coherence tomography central subfield retinal thickness (-11.7 ▒ 7.0% for study eyes and -2.9 ▒ 3.5% for fellow eyes) were greater in study eyes compared with fellow eyes.Despite significant anatomical responses to treatment, functional improvement in visual acuity was not detected. Intravitreal ranibizumab administered monthly over a time course of 12 months is unlikely to provide a general and significant benefit to patients with nonneovascular idiopathic macular telangiectasia Type 2.

    View details for DOI 10.1097/IAE.0b013e31824690a8

    View details for Web of Science ID 000303502200018

    View details for PubMedID 22266930

  • Risk Factors Associated with Incident Cataracts and Cataract Surgery in the Age-Related Eye Disease Study (AREDS) AREDS Report Number 32 OPHTHALMOLOGY Chang, J. R., Koo, E., Agron, E., Hallak, J., Clemons, T., Azar, D., Sperduto, R. D., Ferris, F. L., Chew, E. Y. 2011; 118 (11): 2113-2119


    To investigate potential risk factors associated with incident nuclear, cortical, and posterior subcapsular (PSC) cataracts and cataract surgery in participants in the Age-Related Eye Disease Study (AREDS).Clinic-based prospective cohort study.Persons (n = 4425) 55 to 80 years of age enrolled in a controlled clinical trial of antioxidant vitamins and minerals, AREDS, for age-related macular degeneration and cataract.Lens photographs were graded centrally for nuclear, cortical, and PSC opacities using the AREDS system for classifying cataracts. Type-specific incident cataracts were defined as an increase in cataract grade from none or mild at baseline to a grade of moderate at follow-up, also with a grade of at least moderate at the final visit, or cataract surgery. Cox regression analyses were used to assess baseline risk factors associated with type-specific opacities and cataract surgery.Moderate cataract was defined as a grade of 4.0 or more for nuclear opacity, 10% or more involvement within the full visible lens for cortical opacity, and 5% or more involvement of the central 5-mm circle of the lens for PSC opacity. These were graded on baseline and annual lens photographs.A clinic-based cohort of 4425 persons 55 to 80 years of age at baseline was followed up for an average of 9.8▒2.4 years. The following associations were found: increasing age with increased risk of all types of cataract and cataract surgery; males with increased risk of PSC and decreased risk of cortical cataracts; nonwhite persons with increased risk of cortical cataract; hyperopia with decreased risk of PSC, nuclear cataract, and cataract surgery; Centrum (Wyeth Consumer Healthcare, Madison, NJ) use with decreased risk of nuclear cataract; diabetes with increased risk of cortical, PSC cataract, and cataract surgery; higher educational level with decreased risk of cortical cataract; and smoking with increased risk of cortical cataract and cataract surgery. Estrogen replacement therapy in female participants increased the risk of cataract surgery.These findings largely are consistent with the results of previous studies, providing further evidence for possible modifiable risk factors for age-related cataract.The author(s) have no proprietary or commercial interest in any materials discussed in this article.

    View details for DOI 10.1016/j.ophtha.2011.03.032

    View details for Web of Science ID 000296573500003

    View details for PubMedID 21684602

  • Expanding indications for the Boston keratoprosthesis CURRENT OPINION IN OPHTHALMOLOGY Colby, K. A., Koo, E. B. 2011; 22 (4): 267-273


    To review emerging indications for the Boston keratoprosthesis (KPro) and to discuss current research underway to improve clinical outcomes.In addition to multiple failed corneal grafts, other ocular conditions for which the Boston KPro has been used include herpetic keratitis, aniridia, autoimmune ocular disorders, and pediatric corneal opacities. In the recent years, the KPro has been implanted for various other conditions and has also been explored as a cost-effective treatment for severe corneal diseases internationally. Cicatricial and inflammatory ocular conditions remain the most difficult cases for KPro use but studies investigating various immunomodulators and biologic materials for improved retention are ongoing. Postoperative management of glaucoma is critical for preserving the visual gains achieved with the Boston KPro. Current studies are evaluating novel devices for intraocular pressure measurement.Accrued experience with the Boston KPro has demonstrated its versatility but also the difficulties that remain in postoperative management. With many studies underway to improve cost-effectiveness, intra-operative and postoperative management, keratoprostheses will be made increasingly available to those countries most in need.

    View details for DOI 10.1097/ICU.0b013e3283477d0d

    View details for Web of Science ID 000291429100010

    View details for PubMedID 21537184

  • Spatial summation of mechanically evoked muscle pain and painful aftersensations in normal subjects and fibromyalgia patients PAIN Staud, R., Koo, E., Robinson, M. E., Price, D. D. 2007; 130 (1-2): 177-187


    Impulse frequency and number of recruited central neurons are relevant for pain encoding and temporal as well as spatial summation of pain (SSP). Whereas SSP of heat-induced pain is well characterized, mechanical SSP (MSSP) has been less studied. MSSP may be relevant for chronic pain conditions like fibromyalgia (FM) and play an important role in the pathogenesis of this chronic pain syndrome. Our study was designed to determine MSSP in 12 normal controls (NC) and 11 FM subjects. MSSP testing consisted of 5 s suprathreshold pressure-pain stimulations of forearm muscles by up to three identical probes (separated by 4 or 8 cm). The stimulated areas ranged between 0.79 and 2.37 cm2. The subjects rated the pain intensity of mechanical stimuli as well as pain aftersensations. Although MSSP increased monotonically in NC and FM subjects, pressure pain and pressure pain aftersensations were greater in FM subjects and highly associated with clinical pain intensity (r2=.44-.64), suggesting that spatial and temporal summation factors may contribute to overall clinical pain. However, despite higher experimental pain ratings, the magnitude of MSSP was not statistically different between NC and FM subjects. Furthermore, muscle stimuli elicited more MSSP when separated by 8 cm than 4 cm and this finding was not different between NC and FM subjects. Thus, mechanisms of MSSP were similar for both FM and NC subjects. The important role of MSSP for pain encoding suggests that decreasing pain in some muscle areas by local anesthetics or other means may improve overall clinical pain of FM patients.

    View details for DOI 10.1016/j.pain.2007.03.015

    View details for Web of Science ID 000247754300022

    View details for PubMedID 17459587

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