Which testing method is better for detecting the progression of Retinitis pigmentosa?

The electroretinogram (ERG) is a critical tool for assessing retinal function in patients with Retinitis pigmentosa (RP). This condition is characterized by progressive degeneration of photoreceptor cells in the retina, primarily affecting rods and eventually cones. As the disease progresses, the ERG can provide valuable data on the integrity and function of these cells.

The ERG measures the electrical responses of the retina to light stimulation, allowing clinicians to evaluate the function of both rod and cone photoreceptors. In the early stages of Retinitis pigmentosa, the ERG may show diminished responses primarily due to the loss of rod function. As the condition advances, the response may further decline, indicating progression of the disease. Therefore, tracking changes in the ERG over time can effectively demonstrate the extent of retinal degeneration and help in assessing disease progression.

Other testing methods, while useful in certain contexts, do not correlate as directly with the specific functional impairment caused by Retinitis pigmentosa. For instance, the electro-oculogram (EOG) primarily measures the function of the retinal pigment epithelium rather than the retina itself, making it less suitable for monitoring RP progression. Optical coherence tomography (OCT) is excellent for visualizing structural changes in the