? The most common method of slit lamp is to directly focus illumination, turn on the light source, and project it on the eyes from the right or left side at an angle of 45 ~65 degrees. Adjust the crack to a very thin width to form a "light knife" and focus the microscope clearly on the observed tissue. We usually check the eyelids and conjunctiva, tear film, cornea, anterior chamber, iris and pupil, lens and vitreous body first.
? When checking eyelids and conjunctiva, adjust the brightness of slit lamp to medium, and check with diffuse light illumination method under low power microscope. Pay attention to the normal anatomical structure of the eyelid, starting from the right eye and from the nasal side to the temporal side. Look at the eyelids and upper eyelids first to see if there are hair follicles or stones. Generally, follicles will see particles with small bubbles, while stones will have yellow and white spots. Then observe the bulbar conjunctiva, which is a transparent membrane on the sclera. Observe whether there is edema, dryness and vascular abnormality in the bulbar conjunctiva here. Check subconjunctival bleeding, secretions and other abnormalities. If there is a problem, you need to zoom in.
? When examining the tear film, you need to order fluorescein first, and the tears are common green. When observed with cobalt blue light under low diffuse light, the shape of tear river on bulbar conjunctiva above the lower eyelid margin can be seen. Here, we will evaluate the height of the tear river, observe the cornea under a microscope, and then instruct the examiner to blink. When the yellow-green film appears black for the first time, it means that the tear film is broken, and the rupture time is recorded. The normal rupture time is (10-45 seconds). If it is less than 10 second, the tear film is abnormal. If it is less than 5 seconds, there may be dry eye, which needs to be combined with other examinations and diagnosis.
? Corneal examination uses direct illumination and indirect illumination, and back illumination is used alternately. Adjust the angle and width of the slit light source, also from the nasal side to the temporal side. The normal cornea is halo and shadow except the scleral edge, and the cornea itself can be completely clear, and the light band will be gray-blue when passing through. If the cornea is abnormal, will there be gray shadows in the field of vision of the microscope? On the cornea in the middle. If the cornea has epithelial injury or corneal ulcer, it can be further examined by fluorescein staining to confirm its severity. If there is damage, you can see bright green staining and complete epithelium. This place has no color.
? Check the anterior chamber, direct focus illumination makes the focus move into the anterior chamber, and the length of the crack as a light source is reduced. Make the incident light form a small column, and then project it into the anterior chamber to observe whether the anterior chamber is transparent. If the anterior chamber light band is white and flashing, it indicates that the protein content in the anterior chamber water is increased. The destruction of blood-aqueous barrier function is an important sign of iris inflammation.
? Iris and pupil, mainly to observe whether the iris texture is clear, whether the color is normal, whether there are iris tremor, nodules, new blood vessels, cracks, perforations, or foreign bodies. Is it related to the cornea? Or lens adhesion. Compare pupil size. And whether it is sensitive to light reflection.
Lens examination, the light from the small crack is projected on the lens at a 45-degree angle, and a well-defined long cube can be seen. See if it is transparent and the position is normal.
Vitrectomy. Under normal circumstances, the anterior 1/3 vitreous body is a loose and amorphous gauze-like structure. At present, when there is bleeding and inflammation in the vitreous body, red blood or inflammation can be seen. The exudate is floating. After examination and treatment, a front mirror is needed.