Thursday, April 7, 2016

Ophthalmic Nerve Sonography: Update

I need to restrain myself.  I have encountered an article which may contain truths, and half truths.  I will try to explain.  The measurements of the ophthalmic nerve for non-invasive evidence of increased intracranial pressure was pioneered by NASA and the Russian Space agency because of issues with astronauts and cosmonauts returning to earth with blurring eye site, and other signs of neural impairments due to the time spent in micro gravity. This has been known for many years.  It is known that micro gravity causes an imbalance in the CSF in the brain and spinal column of astronauts, which can result in strange effects.  These effects, specifically on intracranial pressure have been studied well by many countries participating in the ISIS.  The use of non-invasive ocular ultrasound was demonstrated many years ago, by measuring the diameter of the optic nerve using and ultrasound probe sending sonic waves to image the optic nerve through the closed eye-lid.  I will cite a couple articles:

ISS Science for Everyone
Science Objectives for Everyone 
The Vision Impairment and Intracranial Pressure (VIIP) project examined the effect of long-term exposure to microgravity on the structure of the eye along with change in distance and near vision of crew members before and after they returned to Earth.
Science Results for Everyone 
I can see (less) clearly now. Many astronauts experience poorer vision after flight, some even for years after. A number of studies have looked for causes and distinct physical changes in the eye itself have been found. MRI scans suggest that pressure changes in the brain and spinal fluid caused by weightlessness may be partly to blame. Many astronauts do not show these effects, though, and more advanced imaging techniques may be needed to understand the role of changing brain pressure in microgravity. This in turn will help researchers assess vision problems and develop ways to prevent them.  

This was published 5-13-15

Thanks NASA/gov

Next is a breaking article TODAY!

Breaking News: Ocular Sonography Detects Intracranial Pressure

SoRelle, Ruth MPH

This is so interesting that science journalists lag so far behind the times.

Faced with a patient in the emergency department who might have increased intracranial pressure, Kristi Koenig, MD, reaches for one of her most valuable tools — the ultrasound machine — to rule out the possibility that forces are building inside the skull.

Thanks Live Science
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