Ophthalmoscope can be divided into direct ophthalmoscope and indirect ophthalmoscope two kinds.
Direct ophthalmoscope can directly examine the fundus without dilating the pupil. The examination is carried out in a dark room. The examiner's eyes must be close to the patient's eyes, check the patient's right eye with the right eye, hold the ophthalmoscope in the right hand of the patient, sit or stand on the right side of the patient, and the left eye is vice versa. Use +10D lens to check whether the patient's dioptric interstitium is transparent, after checking the dioptric interstitium, you can begin to examine all parts of the fundus, rotate the disc of the lens to correct the doctor and the patient's refractive errors, if the doctor is emmethean or has been equipped with corrective glasses, the diopter used to see the fundus indicates the refractive condition of the examined eye.
Generally, the affected eye is looked straight forward, the optic papilla is examined, and then the superior temporal, infratemporal, superior nasal, and inferior nasal quadrants are examined along the omental vessels. Finally, the affected eye is fixed on the temporal side, and the macula is examined. The size of the fundus lesion was expressed by the diameter of the optic nipple, and the degree of curvature of the lesion was measured by the diopter of the lens. 3D was equivalent to 1mm. Some ophthalmoscopes are equipped with green filters for better observation of optic nerve fibers and macula.
When the indirect ophthalmoscope is used, the pupil must be fully dilated and examined in the dark room. The doctor should switch on the power supply, adjust the distance and the position of the mirror, observe with weak light first, see the opacity of the cornea, crystal and vitreous body, and then direct the light into the pupil of the examined eye, and let the examined eye focus on the light source. Generally, the +20D objective lens is placed at 5cm in front of the examined eye. The convex surface of the objective lens faces the examiner, the examiner holds the objective lens with his left hand, and fixes it on the orbital margin of the patient. The examined eye, the objective lens, and the head of the examiner are fixed. When the optical papilla and macula are seen, the objective lens is moved to the direction of the examiner, and the stereoscopic inversion of the optical papilla and macula can be clearly seen at 5cm in front of the subject.
When examining the rest of the fundus, the subject should be able to move his eyes to cooperate with the examination, and the examiner should move around the subject's head, and the hand-held objective and the examiner's head should move accordingly. The images are opposite up and down, opposite left and right. To examine the periphery of the fundus, such as the 6 o 'clock position, the examiner is located on the top of the client's head, so that the affected eye looks down at the 6 o 'clock position. The examination of the far peripheral part of the fundus must be combined with scleral compression method. The metal scleral compression device is worn on the middle or index finger of the right hand of the inspector, and the head of the compression device is placed outside the corresponding eyelid of the examined eye. If necessary, the examination can be carried out from the conjunctival sac after epimanaesthesia. During the operation, the line of sight of the examiner should be kept in a straight line with the illumination of the indirect ophthalmoscope, the focus of the objective lens, the inspected eye position, and the head of the oppressor. During the examination, attention should be paid to asking the patient to close the eyelid at any time to wet the cornea. When there is a suspected intraocular space occupying lesion, pressure examination should be avoided.