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Pediatric Ophthalmology and Adult Strabismus

Dr. Michael Repka with child patient

Wilmer's Division of Pediatric Ophthalmology and Adult Strabismus treats the full spectrum of children's vision problems.

Our specialists are among the top experts in their field and have advanced training in strabismus (both pediatric and adult), amblyopia (lazy eye), congenital and pediatric cataracts, retinopathy of prematurity, pediatric glaucoma and pediatric neuro-ophthalmologic disorders.



Conditions We Treat

Wilmer's Division of Pediatric Ophthalmology and Adult Strabismus provides expert clinical care for eye diseases and conditions including:


Our Team

Chief, Pediatric Ophthalmology and Adult Strabismus


Providers by Location

The Johns Hopkins Hospital

Wilmer - Bel Air


Wilmer - Bethesda


Wilmer - Columbia


Wilmer - Green Spring Station - Lutherville

Wilmer - Frederick



We are committed to the eye health of children, when delivering care in our offices, studying how to expand service for children in our community, and improving clinical outcomes from research into treatments and novel instruments to detect problems early.

- Dr. Michael Repka,  Chief, Division of Pediatric Ophthalmology

Meet our Orthoptists

Orthoptic Department services include diagnostic tests and measurements on patients with disorders of binocular vision and/or visual function deficits.
  • Alex Christoff, BS, CO

    Alex Christoff is an assistant professor of ophthalmology who has been an American Orthoptic Council-Certified orthoptist for 21 years, as well as a JCAHPO-Certified ophthalmic technician for over 30 years. He has devoted his professional career to the education of Wilmer's residents, fellows, orthoptic students, and ophthalmic technicians across the United States through over 200 lectures, posters and presentations. He was the 45th Richard G. Scobee Memorial Lecturer for the American Association of Certified Orthoptists (AACO) in 2014 and is the current president.

    alexander christoff
  • Xiaonong Liu, MSc, CO, COMT

    Xiaonong Liu specializes in the assessment and treatment of children and adult patients with amblyopia, strabismus, diplopia, and eye muscle disorders. She graduated from Suzhou University School of Medicine, then trained and worked as an ophthalmologist in a Suzhou-affiliated teaching hospital. She received a master science degree from State University of New York, School of Optometry, and completed orthoptic training at the University of Florida. She has been an American Orthoptic Council-certified orthoptist since 1999, as well as a JCAHPO-Certified ophthalmic medical technologist since 1998. She started her orthoptist career with University of Maryland and later joined pediatric ophthalmology department at Wilmer Eye Institute, Johns Hopkins University School of Medicine in 2001.

    xiaonong liu
  • Jana Mattheu, CO, COMT

    Jana Mattheu is a certified orthoptist and certified ophthalmic medical technologist. She specializes in both pediatric and adult strabismus and binocular vision. Mrs. Mattheu has nearly 30 years of experience in the field - in both academic and private practice - totaling 10 years with the Wilmer Eye Institute. In 2019, she was a recipient of the Service Star of Excellence award from the Johns Hopkins Medical Institute. Prior to her orthoptic education at the University of Florida, Mrs. Mattheu worked in opticianry. This experience helped her in understanding the optical principles of refracting and crafting lenses, helping to fit patients with complicated spectacle prescriptions, and utilizing prisms to help restore binocular vision. Over the years, Jana has lectured at both regional and national Academy meetings to her peers. She enjoys spending time working one-on-one in clinic educating resident physicians and sharing her tricks to excel in the pediatric and strabismus ophthalmologic exams.

    jana mattheu
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