Retinal Toxicity

Visual electrophysiology for retinal toxicity

The American Academy of Ophthalmology (AAO) recommends the use of objective testing to screen for retinal toxicity. Multifocal electroretinography (mfERG), a test defined by the International Society for Clinical Electrophysiology of Vision (ISCEV), offers an objective assessment of retinal function in patients treated with HCQ/CQ. A 2019 study suggests that while spectral-domain optical coherence tomography (SD-OCT) can detect retinal toxicity, mfERG demonstrates greater sensitivity to retinal dysfunction that may precede structural abnormalities. Also, mfERG can be useful in confirming the absence of retinal toxicity when perimetry or other tests detect abnormalities.

The rERG stimulus pattern has four rings across the central 50° of vision. The ratios of the amplitude densities are calculated from the second or third ring, relative to the fourth (outermost) ring. Reference normative data indicate that measurements using the second ring are suitable for testing subjects of European, African, and Hispanic descent due to their typical parafoveal pattern of toxicity. Measurements using the third ring are suitable for testing subjects of Asian descent, due to their typical peripheral presentation of retinal toxicity damage.