Funduscopic examination: typical funduscopic changes can be observed, mainly include yellowish color of the optic papilla, thinning of the retinal blood vessels, and osteoblastic pigmentation (starting at the equator, the pigmentation is a small protruding dot, which then increases in size, and becomes osteoblastic, and sometimes appears as an irregular line, which is arranged around the equator as a ring of varying widths) triple sign; macular degeneration; lens clouding, i.e., cataracts, especially the posterior capsule, and vitreous clouding. cataracts are common; vitreous clouding.
Functional examination: may be accompanied by astigmatism and myopia, narrowing of the visual field, loss of visual acuity, loss of contrast sensitivity, and blue-blindness in color vision with a lack of blue-sensitive optic vertebral cells.
Dark adaptation test: is a psychophysical measure of visual threshold to light stimuli. The subject is first given a bright light stimulus, then placed in a dark environment for 30 minutes, and the weakest light intensity perceivable by the subject is measured at the interval point. Early stage cone cell function is still normal, and rod cell function declines, raising the rod cell curve end threshold and causing a reduction in the light-color intervals. In the late phase, when rod cell function is lost, the cone cell threshold is also elevated, resulting in a high monophasic curve.
Whole-field electroretinography (ERG): measures the electrical response of the retina to light stimulation and is among the traditional criteria for diagnosing the disease.RP may show a delay in the production of electrical signals from the retina after stimulation and a decrease in wave amplitude. The test is highly sensitive, and the ERG can detect abnormalities even in the early stages of the disease.
Electrooculogram (EOG): reflects the function of the retinal pigment epithelium-photoreceptor complex. Significantly reduced or extinguished LP/DT can be detected even in the early stages, when changes in visual field, dark accommodation, and even ERG are not yet evident. Therefore, EOG is more sensitive than ERG for the diagnosis of this disease.
Fundus angiography: Early in the course of the disease, it shows mottled strong fluorescent spots; when the development of the lesion is obvious, there is a large area of strong translucent fluorescence, and the pigmented area is masked fluorescence. In the late stage, due to choroidal capillary atrophy, and see a large area of weak fluorescence and choroidal blood vessels.