Newer Signatures for Evidence Based Evaluation in Strabismus: Imaging and Genetics
Zia Chaudhuri, FRCS (Glasg), FICO; Joseph L. Demer, MD, PhD
Lady Hardinge Medical College, University of Delhi, New Delhi, India and Stein Eye Institute and Department of Neurology, University of California, Los Angeles, United States of America
New Delhi, India and Los Angeles, United States of America
Purpose/Relevance: With newer modalities of investigations available in the form of high-resolution surface-coil orbital imaging for extraocular muscle (EOM) evaluation, and genetics in the form of next generation sequencing (NGS) tools to assess the etiology of both common and special forms of strabismus, it becomes important for the strabismologist to have an overview.
Target Audience: Strabismologists
Current Practice: Clinical strabismus practices globally do not incorporate these modalities for routine application. While imaging for strabismus is now an established modality for assessing EOM position as well as function, cost is a major impeding factor. Application of NGS in the evaluation of strabismus is relatively new and still in the research domain.
Best Practice: Both imaging and genetics provide customized signatures for the evidence-based diagnosis of conditions including strabismus. Imaging can clarify internal phenotypes not evident on clinical examionation. With the emergent recognition of newer likely genetic determinants of strabismus, basic research supportive of strabismus has become very exciting.
Expected Outcomes: The practicing strabismologist will be informed about the latest available tools in the strabismus diagnosis armamentarium.
- Two lectures on:
a. Imaging as a phenotypic marker in congenital cranial dysinnervation disorders and rectus pulley heterotopy: Professor Joseph L Demer
b. Whole exome sequencing in common forms of strabismus: Professor Zia Chaudhuri
2. Case presentations
3. Question – answer forum
Summary: Evidence based, highly specific diagnostic signatures for strabismus that have long languished in the research domain are now increasingly relevant to the everyday practice of strabismology. EOM imaging is already used for diagnosing difficult cases of strabismus. With advances in genetic tools and relentlessly decreasing cost of many investigations, a plethora of clinical information should soon be available. The practicing strabismologist should be aware of these modalities.
References: 1. Chaudhuri Z, John A, Aneja S, Thelma BK. Identification of a novel putative variant in the EPHA2 gene on chromosome 1p in a family with exotropia by whole exome sequencing. Oral presentation at the ARVO 2017; Program No 3439; Strabismus: Basic and Clinical Session on May 9, 2017 (ARVO 2017 Annual Program Abstracts)
2. Demer JL, Ortube MC, Engle EC, Thacker N. High-resolution magnetic resonance imaging demonstrates abnormalities of motor nerves and extraocular muscles in patients with neuropathic strabismus. J AAPOS. 2006 Apr;10(2):135-42.
3. Demer JL, Clark RA, Engle EC.. Magnetic resonance imaging evidence for widespread orbital dysinnervation in congenital fibrosis of extraocular muscles due to mutations in KIF21A. Invest Ophthalmol Vis Sci. 2005 Feb;46(2):530-9.