Pattern ERG is used to assess which type of vision?

• A. Scotopic
• B. Photopic
• C. Mesopic
• D. Peripheral vision

Answer: (C)

Pattern ERG probes retinal ganglion cell function in the central retina under bright, pattern-stimulus conditions, so it predominantly reflects cone-driven, or photopic, vision. The high-contrast pattern presented in a well-lit field is designed to isolate the central macular response and inner retinal activity, rather than rod-driven responses seen in dark adaptation. Scotopic testing uses dark-adapted flashes to assess rod pathways, while mesopic would involve mixed rod and cone input and isn’t what pattern stimuli target. Peripheral vision isn’t the focus of pattern ERG, which centers on the macula and central retinal function. This makes Pattern ERG especially useful for evaluating central vision integrity and diseases affecting retinal ganglion cells, like glaucoma and macular disorders.