Education & Certifications

  • Bachelor of Science, Duke University, Major in Biology with Minors in Religion and Neuroscience (2011)


  • 2015 Autumn - MED 313A Ambulatory Medicine Core Clerkship
  • 2015 Summer - FAMMED 310A Primary Care Continuity Experience
  • 2015 Summer - OBGYN 300A Obstetrics and Gynecology Core Clerkship
  • 2015 Summer - OPHT 300A Ophthalmology Clerkship
  • 2014 Spring - ANES 306A Critical Care Core Clerkship
  • 2014 Spring - MED 312C Advanced Medicine Clerkship
  • 2014 Spring - PSYC 300A Psychiatry Core Clerkship
  • 2014 Winter - FAMMED 301A Family Medicine Core Clerkship
  • 2014 Winter - PEDS 300A Pediatrics Core Clerkship
  • 2013 Autumn - NENS 301A Neurology Core Clerkship
  • 2013 Autumn - OPHT 398A Elective in Ophthalmology
  • 2013 Autumn - SURG 300A Surgery Core Clerkship
  • 2013 Summer - MED 300A General Medicine Core Clerkship
  • 2013 Summer - SURG 300A Surgery Core Clerkship

Stanford Advisors

Research & Scholarship

Current Research and Scholarly Interests

On research teams analyzing:
1) Tele-ophthalmology and remote triage feasibility with the Stanford EyeGo
2) Reliability and validity of telemedicine in screening newborns for ophthalmic disease
3) Image recognition in urgent ophthalmologic diagnosis

Research Projects

  • Single vs. Multiple Fractionations in the Treatment of Acoustic Neuromas (MedScholars Project)
  • Acute Lung Injury in Patients with Subarachnoid Hemorrhage: National Inpatient Sample Study (MedScholars Project)
  • Tele-ophthalmology and Remote Triage Feasibility Study in Rural India and Stanford Byers Eye Institute using the EyeGo Low-Cost Smartphone Adapters for Anterior Segment Imaging and Indirect Ophthalmoscopy (MedScholars Project)

Lab Affiliations


2014-15 Courses


All Publications

  • What colour are newborns' eyes? Prevalence of iris colour in the Newborn Eye Screening Test (NEST) study. Acta ophthalmologica Ludwig, C. A., Callaway, N. F., Fredrick, D. R., Blumenkranz, M. S., Moshfeghi, D. M. 2016


    This study aims to assess the birth prevalence of iris colour among newborns in a prospective, healthy, full-term newborn cohort.The Newborn Eye Screening Test (NEST) study is a prospective cohort study conducted at Lucile Packard Children's Hospital at Stanford University School of Medicine. A paediatric vitreoretinal specialist (DMM) reviewed images sent to the Byers Eye Institute telemedicine reading centre and recorded eye colour for every infant screened. Variables were graphed to assess for normality, and frequencies per subject were reported for eye colour, sex, ethnicity and race.Among 192 subjects screened in the first year of the NEST study with external images of appropriate quality for visualization of the irides, the birth prevalence of iris colour was 63.0% brown, 20.8% blue, 5.7% green/hazel, 9.9% indeterminate and 0.5% partial heterochromia. The study population was derived from a quaternary care children's hospital. We report the birth prevalence of iris colour among full-term newborns in a diverse prospective cohort.The study demonstrates a broad range of iris colour prevalence at birth with a predominance of brown iris coloration. Future studies with the NEST cohort will assess the change in iris colour over time and whether the frequencies of eye colour change as the child ages.

    View details for DOI 10.1111/aos.13006

    View details for PubMedID 27061128

  • A novel smartphone ophthalmic imaging adapter: User feasibility studies in Hyderabad, India. Indian journal of ophthalmology Ludwig, C. A., Murthy, S. I., Pappuru, R. R., Jais, A., Myung, D. J., Chang, R. T. 2016; 64 (3): 191-200


    To evaluate the ability of ancillary health staff to use a novel smartphone imaging adapter system (EyeGo, now known as Paxos Scope) to capture images of sufficient quality to exclude emergent eye findings. Secondary aims were to assess user and patient experiences during image acquisition, interuser reproducibility, and subjective image quality.The system captures images using a macro lens and an indirect ophthalmoscopy lens coupled with an iPhone 5S. We conducted a prospective cohort study of 229 consecutive patients presenting to L. V. Prasad Eye Institute, Hyderabad, India. Primary outcome measure was mean photographic quality (FOTO-ED study 1-5 scale, 5 best). 210 patients and eight users completed surveys assessing comfort and ease of use. For 46 patients, two users imaged the same patient's eyes sequentially. For 182 patients, photos taken with the EyeGo system were compared to images taken by existing clinic cameras: a BX 900 slit-lamp with a Canon EOS 40D Digital Camera and an FF 450 plus Fundus Camera with VISUPAC™ Digital Imaging System. Images were graded post hoc by a reviewer blinded to diagnosis.Nine users acquired 719 useable images and 253 videos of 229 patients. Mean image quality was ≥ 4.0/5.0 (able to exclude subtle findings) for all users. 8/8 users and 189/210 patients surveyed were comfortable with the EyeGo device on a 5-point Likert scale. For 21 patients imaged with the anterior adapter by two users, a weighted κ of 0.597 (95% confidence interval: 0.389-0.806) indicated moderate reproducibility. High level of agreement between EyeGo and existing clinic cameras (92.6% anterior, 84.4% posterior) was found.The novel, ophthalmic imaging system is easily learned by ancillary eye care providers, well tolerated by patients, and captures high-quality images of eye findings.

    View details for DOI 10.4103/0301-4738.181742

    View details for PubMedID 27146928

  • Retinal and Optic Nerve Hemorrhages in the Newborn Infant: One-Year Results of the Newborn Eye Screen Test Study. Ophthalmology Callaway, N. F., Ludwig, C. A., Blumenkranz, M. S., Jones, J. M., Fredrick, D. R., Moshfeghi, D. M. 2016


    To report the birth prevalence, risk factors, characteristics, and location of fundus hemorrhages (FHs) of the retina and optic nerve present in newborns at birth.Prospective cohort study at Stanford University School of Medicine.All infants who were 37 weeks postmenstrual age or older and stable were eligible for screening. Infants with known or suspected infectious conjunctivitis were excluded.Infants born at Lucile Packard Children's Hospital (LPCH) from July 25, 2013, through July 25, 2014, were offered universal newborn screening via wide-angle digital retinal photography in the Newborn Eye Screen Test study. Maternal, obstetric, and neonatal factors were obtained from hospital records. The location, retinal layer, and laterality of FH were recorded by 1 pediatric vitreoretinal specialist.Birth prevalence of FH. Secondary outcomes included rate of adverse events, risk factors for FH, hemorrhage characteristics, and adverse events.The birth prevalence of FH in this study was 20.3% (41/202 infants). Ninety-five percent of FHs involved the periphery, 83% involved the macula, and 71% involved multiple layers of the retina. The fovea was involved in 15% of FH cases (birth prevalence, 3.0%). No cases of bilateral foveal hemorrhage were found. Fundus hemorrhages were more common in the left eye than the right. Fundus hemorrhages were most commonly optic nerve flame hemorrhages (48%) and white-centered retinal hemorrhages (30%). Retinal hemorrhages were found most frequently in all 4 quadrants (35%) and more often were multiple than solitary. Macular hemorrhages most often were intraretinal (40%). Among the risk factors examined in this study, vaginal delivery compared with cesarean section (odds ratio [OR], 9.34; 95% confidence interval [CI], 2.57-33.97) showed the greatest level of association with FH. Self-identified ethnicity as Hispanic or Latino showed a protective effect (OR, 0.43; 95% CI, 0.20-0.94). Other study factors were not significant.Fundus hemorrhages are common among newborns. They often involve multiple areas and layers of the retina. Vaginal delivery was associated with a significantly increased risk of FH, whereas self-identified Hispanic or Latino ethnicity was protective against FH in this study. The long-term consequences of FH on visual development remain unknown.

    View details for DOI 10.1016/j.ophtha.2016.01.004

    View details for PubMedID 26875004

  • Mobile Health in the Retinal Clinic Population: Access to and Interest in Self-Tracking. Ophthalmic surgery, lasers & imaging retina Ludwig, C. A., Callaway, N. F., Park, J. H., Leng, T. 2016; 47 (3): 252-7


    Implementation of mobile health-tracking programs for retinal pathology requires both access to mobile devices and patient motivation to participate in self-tracking. The authors' study aimed to evaluate the prevalence of smartphone and tablet ownership and patient interest in self-tracking among a retinal clinic population.This is an institutional, prospective, cross-sectional survey of 103 retinal clinic outpatients. Consenting patients underwent a one-on-one interview conducted in the examination room during their waiting period by one researcher.Overall, 75 of 103 participants (72.2%) reported either owning a smartphone and/or tablet or having access at their household to a device that could be used to track eye health. The majority of participants (69 of 103 participants; 67%) reported interest in using a mobile application (smartphone or tablet) to track their eye health.These data suggest strong patient interest in the use of mobile devices to track eye health. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:252-257.].

    View details for DOI 10.3928/23258160-20160229-08

    View details for PubMedID 26985799

  • Altered Innervation Pattern in Ligaments of Patients with Basal Thumb Arthritis. Journal of wrist surgery Ludwig, C. A., Mobargha, N., Okogbaa, J., Hagert, E., Ladd, A. L. 2015; 4 (4): 284-291


    Purpose The population of mechanoreceptors in patients with osteoarthritis (OA) lacks detailed characterization. In this study, we examined the distribution and type of mechanoreceptors of two principal ligaments in surgical subjects with OA of the first carpometacarpal joint (CMC1). Methods We harvested two ligaments from the CMC1 of eleven subjects undergoing complete trapeziectomy and suspension arthroplasty: the anterior oblique (AOL) and dorsal radial ligament (DRL). Ligaments were divided into proximal and distal portions, paraffin-sectioned, and analyzed using immunoflourescent triple staining microscopy. We performed statistical analyses using the Wilcoxon Rank Sum test and ANOVA with post-hoc Bonferroni and Tamhane adjustments. Results The most prevalent nerve endings in the AOL and DRL of subjects with OA were unclassifiable mechanoreceptors, which do not currently fit into a defined morphological scheme. These were found in 11/11 (100%) DRLs and 7/11 (63.6%) AOLs. No significant difference existed with respect to location within the ligament (proximal versus distal) of mechanoreceptors in OA subjects. Conclusion The distribution and type of mechanoreceptors in cadavers with no to mild OA differ from those in surgical patients with OA. Where Ruffini endings predominate in cadavers with no to mild OA, unclassifiable corpuscles predominate in surgical patients with OA. These findings suggest an alteration of the mechanoreceptor population and distribution that accompanies the development of OA. Clinical Relevance Identification of a unique type and distribution of mechanoreceptors in the CMC1 of symptomatic subjects provides preliminary evidence of altered proprioception in OA.

    View details for DOI 10.1055/s-0035-1564982

    View details for PubMedID 26649261

  • Intracranial fat migration: A newly described complication of autologous fat repair of a cerebrospinal fluid leak following supracerebellar infratentorial approach. International journal of surgery case reports Ludwig, C. A., Aujla, P., Moreno, M., Veeravagu, A., Li, G. 2015; 7C: 1-5


    Intracranial fat migration following autologous fat graft and placement of a lumbar drain for cerebrospinal fluid leak after pineal cyst resection surgery has not been previously reported.The authors present a case of a 39-year-old male with a history of headaches who presented for removal of a pineal cyst from the pineal region. He subsequently experienced cerebrospinal fluid leak and postoperative Escherichia coli (E. Coli) wound infection, and meningitis, which were treated initially with wound washout and antibiotics in addition to bone removal and primary repair with primary suture-closure of the durotomy. A lumbar drain was left in place. The cerebrospinal fluid leak returned two weeks following removal of the lumbar drain; therefore, autologous fat graft repair and lumbar drain placement were performed. Three days later, the patient began experiencing right homonymous hemianopia and was found via computed tomography and magnetic resonance imaging to have autologous fat in the infra‑ and supratentorial space, including intraparenchymal and subarachnoid spread. Symptoms began to resolve with supportive care over 48 hours and had almost fully resolved within one week.This is the first known report of a patient with an autologous fat graft entering the subarachnoid space, intraparenchymal space, and ventricles following fat graft and lumbar drainage.This case highlights the importance of monitoring for complications of lumbar drain placement.

    View details for DOI 10.1016/j.ijscr.2014.12.008

    View details for PubMedID 25557086

  • Idiopathic pigmented vitreous cyst. Acta ophthalmologica Ludwig, C. A., Leng, T. 2015

    View details for DOI 10.1111/aos.12785

    View details for PubMedID 26095667

  • Acute Lung Injury in Patients with Subarachnoid Hemorrhage: A Nationwide Inpatient Sample Study WORLD NEUROSURGERY Veeravagu, A., Chen, Y., Ludwig, C., Rincon, F., Maltenfort, M., Jallo, J., Choudhri, O., Steinberg, G. K., Ratliff, J. K. 2014; 82 (1-2): E235-E241
  • Ultrastructure and Innervation of Thumb Carpometacarpal Ligaments in Surgical Patients With Osteoarthritis CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Mobargha, N., Ludwig, C., Ladd, A. L., Hagert, E. 2014; 472 (4): 1146-1154


    BACKGROUND: The complex configuration of the thumb carpometacarpal (CMC-1) joint relies on musculotendinous and ligamentous support for precise circumduction. Ligament innervation contributes to joint stability and proprioception. Evidence suggests abnormal ligament innervation is associated with osteoarthritis (OA) in large joints; however, little is known about CMC-1 ligament innervation characteristics in patients with OA. We studied the dorsal radial ligament (DRL) and the anterior oblique ligament (AOL), ligaments with a reported divergent presence of mechanoreceptors in nonosteoarthritic joints. QUESTIONS/PURPOSES: This study's purposes were (1) to examine the ultrastructural architecture of CMC-1 ligaments in surgical patients with OA; (2) to describe innervation, specifically looking at mechanoreceptors, of these ligaments using immunohistochemical techniques and compare the AOL and DRL in terms of innervation; and (3) to determine whether there is a correlation between age and mechanoreceptor density. METHODS: The AOL and DRL were harvested from 11 patients with OA during trapeziectomy (10 women, one man; mean age, 67 years). The 22 ligaments were sectioned in paraffin and analyzed using immunoflourescent triple staining microscopy. RESULTS: In contrast to the organized collagen bundles of the DRL, the AOL appeared to be composed of disorganized connective tissue with few collagen fibers and little innervation. Mechanoreceptors were identified in CMC-1 ligaments of all patients with OA. The DRL was significantly more innervated than the AOL. There was no significant correlation between innervation of the DRL and AOL and patient age. CONCLUSIONS: The dense collagen structure and rich innervation of the DRL in patients with OA suggest that the DRL has an important proprioceptive and stabilizing role. CLINICAL RELEVANCE: Ligament innervation may correlate with proprioceptive and neuromuscular changes in OA pathophysiology and consequently support further investigation of innervation in disease prevention and treatment strategies.

    View details for DOI 10.1007/s11999-013-3083-7

    View details for Web of Science ID 000332576400016

  • Radiosurgery for Intramedullary Spinal Cord Tumors Pineal, Pituitary, and Spinal Tumors Veeravagu, A., Ludwig, C., Jiang, B., Chang, S. D. Springer Netherlands. 2014; 1: 213-221
  • Fungal infection of a ventriculoperitoneal shunt: histoplasmosis diagnosis and treatment. World neurosurgery Veeravagu, A., Ludwig, C., Camara-Quintana, J. Q., Jiang, B., Lad, N., Shuer, L. 2013; 80 (1-2): 222 e5-13


    BACKGROUND: Histoplasmosis is a fungal disease caused by Histoplasma capsulatum, commonly found in the Americas, and Histoplasma duboisii, located in Africa. In the United States, H. capsulatum is prevalent in the Ohio and Mississippi river valleys. In rare circumstances, central nervous system (CNS) histoplasmosis infection can be caused by shunt placement. We present a case report of a 45-year-old woman in whom CNS histoplasmosis developed after having a ventriculoperitoneal (VP) shunt placed for communicating hydrocephalus. A review of the literature on fungal infections after CNS shunt placement as well as treatment options for this subset of patients was undertaken. METHODS: The PubMed database current to 1958 was filtered and limited to English-language articles. Fifty-eight articles were selected for review based on evidence of information regarding the fungal organism responsible for shunt infection, symptoms, treatment, and/or outcomes. Also included in this review is our case study. RESULTS: A thorough analysis of the PubMed database revealed 58 reported cases of CNS shunt-related fungal infections in the English-language medical literature as well as 7 therapeutic agents used to treat patients in whom postshunt fungal infections developed. CONCLUSIONS: We describe the steps in diagnosis of histoplasmosis after shunt placement, provide an effective therapeutic regimen, and review the present understanding of CNS fungal infections. The medical literature was surveyed to compare and analyze various CNS fungal infections that can arise from shunt placement as well as treatments rendered.

    View details for DOI 10.1016/j.wneu.2012.12.016

    View details for PubMedID 23247021

  • Traumatic epistaxis: Skull base defects, intracranial complications and neurosurgical considerations. International journal of surgery case reports Veeravagu, A., Joseph, R., Jiang, B., Lober, R. M., Ludwig, C., Torres, R., Singh, H. 2013; 4 (8): 656-661


    Endonasal procedures may be necessary during management of craniofacial trauma. When a skull base fracture is present, these procedures carry a high risk of violating the cranial vault and causing brain injury or central nervous system infection.A 52-year-old bicyclist was hit by an automobile at high speed. He sustained extensive maxillofacial fractures, including frontal and sphenoid sinus fractures (Fig. 1). He presented to the emergency room with brisk nasopharyngeal hemorrhage, and was intubated for airway protection. He underwent emergent stabilization of his nasal epistaxis by placement of a Foley catheter in his left nare and tamponade with the Foley balloon. A six-vessel angiogram showed no evidence of arterial dissection or laceration. Imaging revealed inadvertent insertion of the Foley catheter and deployment of the balloon in the frontal lobe (Fig. 2). The balloon was subsequently deflated and the Foley catheter removed. The patient underwent bifrontal craniotomy for dural repair of CSF leak. He also had placement of a ventriculoperitoneal shunt for development of post-traumatic hydrocephalus. Although the hospital course was a prolonged one, he did make a good neurological recovery.The authors review the literature involving violation of the intracranial compartment with medical devices in the settings of craniofacial trauma.Caution should be exercised while performing any endonasal procedure in the settings of trauma where disruption of the anterior cranial base is possible.

    View details for DOI 10.1016/j.ijscr.2013.04.033

    View details for PubMedID 23792475

  • Biopsy versus resection for the management of low-grade gliomas. Cochrane database of systematic reviews Veeravagu, A., Jiang, B., Ludwig, C., Chang, S. D., Black, K. L., Patil, C. G. 2013; 4: CD009319-?


    Low-grade gliomas (LGG) constitute a class of slow-growing primary brain neoplasms. Patients with clinically and radiographically suspected LGG have two initial surgical options, biopsy or resection. Biopsy can provide a histological diagnosis with minimal risk but does not offer a direct treatment. Resection may have additional benefits such as increasing survival and delaying recurrence, but is associated with a higher risk for surgical morbidity. There remains controversy about the role of biopsy versus resection and the relative clinical outcomes for the management of LGG.To assess the clinical effectiveness of biopsy compared to surgical resection in patients with a new lesion suspected to be a LGG.The following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 11), MEDLINE (1950 to week 3 November 2012), EMBASE (1980 to Week 46 2012). Unpublished and grey literature including Metaregister, Physicians Data Query,,, and were also queried for ongoing trials.Patients of any age with a suspected intracranial LGG receiving biopsy or resection within a randomized clinical trial (RCT) or controlled clinical trial (CCT) were included. Patients with prior resections, radiation therapy, or chemotherapy for LGG were excluded. Outcome measures included overall survival (OS), progression free survival (PFS), functionally independent survival (FIS), adverse events, symptom control, and quality of life (QoL).A total of 2764 citations were searched and critically analyzed for relevance. This effort was undertaken by three independent review authors.No RCTs of biopsy or resection for LGG were identified. Twenty other studies were retrieved for analysis based on pre-specified selection criteria. Ten studies were retrospective or literature reviews. Three studies were prospective but were limited to tumor recurrence or the extent of resection. One study was a population-based parallel cohort and not an RCT. Four studies were RCTs, however patients were randomized with respect to varying radiotherapy regimens to assess timing and dose of radiation. One RCT was focused on high-grade gliomas and not LGG. One last RCT evaluated diffusion tensor imaging (DTI)-based neuro-navigation for surgical resection.Currently there are no randomized clinical trials or controlled clinical trials available on which to base clinical decisions. Therefore, physicians must approach each case individually and weigh the risks and benefits of each intervention until further evidence is available. Future research could focus on randomized clinical trials to determine outcomes benefits for biopsy versus resection.

    View details for DOI 10.1002/14651858.CD009319.pub2

    View details for PubMedID 23633369

  • From the Patient’s Point of View: Patient Centered Outcomes in Spine Surgery Cureus Cassie A. Ludwig, Anand Veeravagu, Michael Zhang, Mitchel G. Maltenfort, Phillip Dowzicky, John K. Ratliff 2013; 5 (4)