In the news: Overview: Nutritional Optic Neuropathies; State of Omega-3s & Corneal Nerve Health

Nutritional Deficits & Optic Neuropathies

Nutritional deficiency is an under-recognized cause of optic neuropathy. Deficits of certain nutrients have long been thought to be common only in developing countries. However, they are showing up more often in the US with the advent of bariatric surgery, restrictive/selective diets, and the upswing in alcohol dependence. According to a national survey, for example, excessive and binge drinking increased by 21% during the COVID-19 pandemic.

Although nutritional optic neuropathy can cause severe and debilitating vision loss, it is often reversible when it is diagnosed and treated in a timely manner.

A new review(1) on the topic from the Warren Alpert Medical School of Brown University, Department of Neurology, aims to raise awareness of how to identify, diagnose, and manage causes of nutritional optic neuropathies.

The authors provide an extensive overview of how patients with these optic neuropathies present, such as painless bilateral vision loss with distinctive visual field scotomas (blind spot or partial loss of vision in a normal visual field), and anatomic changes in the fundus.

The most common nutritional deficiencies associated with optic neuropathy are highlighted, including vitamin B12, B1 (thiamine) and folic acid. The authors also provide recommendations for the steps in diagnosing and managing these deficiencies, as well as identifying individuals who would benefit from early screening.

The authors point out that loss of visual acuity, color desaturation, and a relative afferent pupillary defect (RAPD) is common for all forms of optic neuropathies. Successful treatment algorithms have evolved from better imaging modalities such as OCT, refined MRI protocols for accurate diagnosis, and the availability of specific biomarkers.

This informative review can be downloaded in full -text PDF from ResearchGate: https://www.researchgate.net/publication/270963605_Approach_to_diagnosis_and_management_of_optic_neuropathy

Omega-3s & Corneal Nerve Health

Another review article(2) worth reading focuses on the topic of omega-3 polyunsaturated fatty acids (PUFAs) and corneal nerve health.

The authors, a team from the University of Melbourne and the New Zealand National Eye Centre, University of Auckland, review the current evidence for the role of omega-3s in maintaining ocular surface health and summarize the potential applications of these PUFAs in managing ocular and systemic conditions that cause corneal nerve damage.

The cornea is the most densely innervated tissue in the body and plays a critical role in maintaining ocular surface integrity. Corneal nerve damage, from local or systemic conditions, can lead to ocular discomfort, pain, impaired wound healing, and if poorly managed, neurotrophic keratopathy – the degenerative disease of the corneal epithelium resulting from impaired corneal innervation.

The authors highlight the neuroprotective properties of these fatty acids. They also discuss their ability to reduce corneal epithelial nerves loss and to promote corneal nerve regeneration in diabetes, as well as their potential role in promoting corneal nerve recovery following corneal surgery.

The abstract and excerpts from the review are available at: https://www.sciencedirect.com/science/article/abs/pii/S1542012422000921?via%3Dihub

References

1. Bhat N and Bakaeva T. Approach to the diagnosis and management of nutritional optic neuropathies. Curr Opin Ophthalmol. 33:507-11, 2022.
2. Britten-Jones A, et al. Omega-3 polyunsaturated fatty acids and corneal nerve health: Current evidence and future directions. Ocular Surface. Available online Oct. 31, 2022.