Electrophysiological Studies in Thyroid Associated Orbitopathy: A Systematic Review

Area of Science:

• Ophthalmology
• Neuroscience
• Clinical Electrophysiology

Background:

• Dysthyroid optic neuropathy (DON) is a leading cause of blindness in thyroid-associated orbitopathy (TAO).
• Current diagnosis of DON is primarily clinical, lacking objective tests for early or uncertain cases.
• Electrophysiological studies (EPS) have been explored for DON, but optimal types and parameters remain unclear.

Purpose of the Study:

• To systematically review electrophysiological studies for diagnosing Dysthyroid optic neuropathy.
• To identify the most effective EPS types and parameters for detecting DON in Thyroid-Associated Orbitopathy patients.

Main Methods:

• A systematic literature search was conducted across MEDLINE, EMBASE, and Cochrane databases up to August 20, 2017.
• 16 original studies, involving 1327 eyes from 787 patients, were included after screening 437 records.
• Pattern visual evoked potential (pVEP) was the most frequently analyzed EPS modality.

Main Results:

• Eyes with DON exhibited delayed P100 latencies and/or decreased P100 amplitudes during pVEP compared to controls.
• Delayed N75 latencies were also observed in pVEP for DON patients.
• Study heterogeneity precluded quantitative meta-analysis, but consistent trends were noted.

Conclusions:

• Pattern visual evoked potential (pVEP) is the most common EPS studied for DON.
• P100 latency and amplitude are key pVEP parameters potentially useful for DON diagnosis.
• Standardized pVEP testing is recommended for future research to improve DON detection.