Blast Exposure Induces Ocular Functional Changes with Increasing Blast Over-pressures in a Rat Model

Area of Science:

• Ophthalmology
• Neuroscience
• Trauma Research

Background:

• Blast-related injuries pose a significant risk for acute and chronic visual dysfunction.
• The long-term visual consequences and progression following blast exposure are not well understood.

Purpose of the Study:

• To analyze ocular functional responses to varying blast exposure levels.
• To identify a blast exposure threshold that causes acute and chronic visual dysfunction.

Main Methods:

• Adult male Long-Evans rats were subjected to single-blast exposures at 78, 117, 164, or 213 kPa.
• Ocular assessments included clinical eye exams, intraocular pressure (IOP) measurements, flash electroretinography (fERG), and spectral-domain optical coherence tomography (SD-OCT).

Main Results:

• No fERG abnormalities were noted at 78 or 117 kPa.
• A 164 kPa blast caused transient fERG deficits and minor IOP fluctuations.
• The 213 kPa blast resulted in significant, temporary IOP elevation and bimodal fERG deficits, with a late-onset depression indicating chronic retinal dysfunction.

Conclusions:

• Single blast exposure can induce acute and chronic fERG deficits and traumatic IOP elevation.
• Noninvasive functional tests are promising for identifying individuals at risk for chronic visual deficits.
• These tests may aid in early clinical diagnosis, rehabilitation, and treatment planning for blast-injured individuals.