Recommended Reading – Treatment of Nystagmus and Saccadic Oscillations

Treatment of Nystagmus and Saccadic Oscillations
Matthew J. Thurtell, and John J. Brinkley/ University of Iowa. EyeRounds.org. 2013
http://webeye.ophth.uiowa.edu/eyeforum/tutorials/Nystagmus/

Introduction
Nystagmus is often encountered in ophthalmology practice, having a prevalence of about 24 per 10,000 in the general population.[1] Unlike physiologic nystagmus, where the slow phases of nystagmus minimize retinal image slip, the slow phases of pathologic nystagmus cause retinal image slip. Retinal image slip of greater than 5 degrees per second produces a decline in visual acuity, partly because the image of the object of interest no longer lies on the fovea, and illusory motion of the visual environment known as oscillopsia.[2,3] Saccadic intrusions and oscillations can also cause visual symptoms, such as difficulty reading, since they take the eye off target so that the image of the object of interest no longer lies on the fovea.[2]

Goals of Treatment
The goal of treatment is to reduce visual symptoms (e.g., blurred vision, oscillopsia) by reducing the speed of nystagmus slow phases or by suppressing saccadic oscillations. Treatments that stop the eyes from moving altogether (e.g., botulinum toxin injections into the extraocular muscles) are not ideal, because they cause oscillopsia during head movements (due to loss of the vestibulo-ocular reflex) and diplopia (due to loss of vergence eye movements).[2] Thus, treatments that suppress the abnormal eye movements without affecting normal eye movements are preferred. Note that some types of nystagmus (e.g., gaze-evoked) and saccadic intrusions (e.g., square-wave jerks) do not usually give visual symptoms and, thus, do not require specific treatment.

General Approaches to Treatment
Treatments for nystagmus that have been proposed include medical, optical, surgical, and other miscellaneous treatments (Table 1); few of these have been evaluated in prospective masked clinical trials.[2,4] Likewise, a variety of treatments for saccadic oscillations have been proposed; few have been evaluated in prospective masked clinical trials.[2] Most treatments aim to suppress the abnormal eye movements without affecting normal eye movements, whereas others aim to negate the visual consequences of the abnormal eye movements. Choice of treatment depends on the type of nystagmus or saccadic oscillation and its characteristics. While some patients will derive benefit from one treatment approach, others require a combination of treatments.[2,4]

Full Article http://webeye.ophth.uiowa.edu/eyeforum/tutorials/Nystagmus/

Recommended Reading – Nystagmus Videos – Neuro-Ophthalmology Virtual Education Library

List of related Videos from the Novel Moran Eye Center – Neuro-Ophthalmology Virtual Education Library

• Peripheral Vestibular Nystagmus
• Downbeat Nystagmus
• Upbeat Nystagmus
• Torsional Nystagmus
• Seesaw Nystagmus | alternative Seesaw Nystagmus
• Periodic Alternating Nystagmus
• Acquired Pendular Nystagmus in MS
• Ocular Flutter
• Opsoclonus

Novel Moran Eye Center – Neuro-Ophthalmology Virtual Education Library

https://collections.lib.utah.edu/search?facet_setname_s=ehsl_novel_jmec

Recommended Reading – The clinical evaluation of infantile nystagmus: What to do first and why

The clinical evaluation of infantile nystagmus: What to do first and why.
Morgan Bertsch, Michael Floyd, Taylor Keohea, Wanda Pfeifer, and Arlene V. Dracka Ophthalmic Genet. 2017 ; 38(1): 22–33.
Department of Ophthalmology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA

Abstract Introduction—Infantile nystagmus has many causes, some life threating. We determined the most common diagnoses in order to develop a testing algorithm.

Methods—Retrospective chart review. Exclusion criteria were no nystagmus, acquired after 6 months, or lack of examination. Data collected: pediatric eye examination findings, ancillary testing, order of testing, referral, and final diagnoses. Final diagnosis was defined as meeting published clinical criteria and/or confirmed by diagnostic testing. Patients with a diagnosis not meeting the definition were “unknown.” Patients with incomplete testing were “incomplete.” Patients with multiple plausible etiologies were “multifactorial.” Patients with negative complete workup were “motor.”

Results—284 charts were identified; 202 met inclusion criteria. The 3 most common causes were Albinism(19%), Leber Congenital Amaurosis(LCA)(14%) and Non-LCA retinal dystrophy (13%). Anatomic retinal disorders comprised 10%, motor another 10%. The most common first test was MRI (74/202) with a diagnostic yield of 16%. For 28 MRI-first patients, nystagmus alone was the indication; for 46 MRI-first patients other neurologic signs were present. 0/28 nystagmus-only patients had a diagnostic MRI while 14/46 (30%) with neurologic signs did. Yield of ERG as first test was 56%, OCT 55%, and molecular genetic testing 47%. 90% of patients had an etiology identified.

Conclusion—The most common causes of infantile nystagmus were retinal disorders (56%), however, the most common first test was brain MRI. For patients without other neurologic stigmata complete pediatric eye examination, ERG, OCT and molecular genetic testing had a higher yield than MRI scan. If MRI is not diagnostic, a complete ophthalmologic workup should be pursued.

Full Article https://drive.google.com/open?id=1h76ziIrxB6TpINMsPF1mcsWvvAvVkaj3