The fundus can be examined without dilating the pupils, but there are limitations to what can be seen.
The blood vessels on the retinal surface of the fundus include retinal arteries, retinal veins, and the macula. When observing the fundus, it is necessary to pass through the pupil, and the normal pupil is only 3mm, so it is difficult to see the peripheral retina in all directions. After dilating the pupil, the pupil can be dilated to 6mm, so the doctor can see the fundus structure more clearly.
However, some patients are not suitable for pupil dilation, such as patients with closed angle glaucoma, only a small piece of retina around the macula of the optic nerve can be observed, and other parts of the fundus have limited scope of examination, so the patient can undergo a wide-angle fundus image examination in order to check the fundus clearly.
It is recommended that patients with abnormal funduscopic examination should consult a doctor in time to evaluate their condition and follow the doctor’s instructions for treatment.