Muhammed, Julieana
(2015)
Evaluation of visual electrophysiology and retinal nerve fiber layer analysis in nonarteritic anterior ischaemic optic neuropathy patients.
Masters thesis, Universiti Sains Malaysia.
Abstract
INTRODUCTION
Nonarteritic anterior ischaemic optic neuropathy (NAION) is a disease among elderly more
than 50 years old that leading to blindness. Assessment and monitoring of this disease is
essential in order to evaluate the structural and functional damage. Visual electrophysiology
tests (pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP)) able to
detect axonal degeneration and functional impairment of retina ganglion cells (RGC) in
patient with NAION. Assessment of Retinal Nerve Fiber Layer (RNFL) with Optical
Coherence Tomography (OCT) provides 3-Dimensional image of RNFL, objectively evaluate
the RNFL thickness and detection of structural damage. It compliments the existing standard
structural and functional test.
OBJECTIVE
To evaluate visual electrophysiology response and retina nerve fibers layer (RNFL) thickness
in NAION. The correlation between visual electrophysiology with RNFL thickness were also
evaluated.
MATERIALS AND METHODS
A comparative cross sectional study was conducted in Hospital Universiti Sains Malaysia
involving 42 samples of NAION patients and controls. A complete ocular examination was
done to confirm the diagnosis of NAION. Evaluation of structural changes of RNFL was
conducted using Cirrus SD-OCT (Carl Zeiss Meditec Inc, USA) with good signal strength (≥
6/10). PERG (0.8º checks size) and PVEP (0.25º checks size) was conducted by a trained
technician. Mann-Whitney test and Spearman’s correlation coefficient analysis were used in
statistical analysis.
RESULTS
There were statistically significant reduction in amplitudes and prolonged in latencies of
PVEP in NAION patients (p<0.001). There were also significant reduction in magnitude of
amplitude (p<0.001) and prolonged latency in PERG (p<0.001). There was also significant
thinning of Mean RNFL thickness in NAION patients (p<0.001). No significant correlation
between RNFL and latency and amplitudes of PVEP and PERG.
CONCLUSION
Visual electrophysiology tests and RNFL analysis has shown significant changes in NAION
patients. This supports that PERG, PVEP and OCT are complimentary tests in assessment
and monitoring structural and functional damage in NAION.
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