I. Examination of the ocular appendages (a) Eyelids Observe for redness, bruising, emphysema, scars or swelling; inversion or ectropion; symmetry of the lid fissures on both sides, and normal upper lid lift and lid closure. The eyelashes are neat and properly oriented, with or without discoloration or loss, and the roots are congested, scaly, pustular or ulcerated. (ii) The lacrimal apparatus Note whether there is ectropion or occlusion of the tear dots; whether there is redness, swelling, pressure or fistula in the lacrimal sac area, and whether there is overflow of secretions from the tear dots by squeezing the lacrimal sac. In tear overflow, the following methods can be taken to check whether there is obstruction of the tear duct. 1.Sodium fluorescein test Put 1%~2% fluorescein nano solution into the conjunctival sac, blow the snot after 2 minutes, such as with greenish yellow, that means the tear duct can pass the tear. 2.Lacrimal flushing Use a small syringe with a blunt needle of No. 6 to inject saline into the lower tear dots, if the patient complains of water flowing into the mouth, nose or pharynx, it also means that the lacrimal tract can pass through the tears. 3.X-ray iodine oil imaging or ultrasonography can further understand the site of tear duct obstruction and the size of the tear sac, so as to consider the surgical problem. 4.The examination of ocular dryness Ocular dryness is caused by the decrease of tear secretion or the abnormality of its composition. Schirmer’s test or examination of tear film rupture time can be used to help diagnosis. (1) Schirmer test: use a 5mm×35mm filter paper, bend one end by 5mm, place it in the inner 1/3 of the conjunctival sac of the lower lid, and drape the rest on the skin surface, close the eyes lightly, and measure the length of the filter paper wetted by tears after 5 minutes. If epi-anesthetic is ordered before the examination, this test mainly evaluates the role of the paracentral lacrimal gland, and a shortening of 5mm is abnormal; if epi-anesthetic is not ordered, the function of the lacrimal gland is evaluated, and a shortening of 10mm is abnormal. (2), measurement of tear film break up time (breaking up time, BUT): observed by slit lamp cobalt blue filter, a drop of 2% sodium fluorescein in the lower temporal part of the bulbar conjunctiva, ask the patient to blink several times to make the fluorescein evenly distributed on the cornea, then open the eyes and stare ahead, no blinking, the examiner from the patient’s eyes open immediately and continuously observe the patient’s cornea, at the same time start timing, until When the first black spot (tear film defect) appears on the cornea, if it is shorter than 10s, it indicates that the tear film is unstable. (iii) Conjunctiva Turn the eyelid up and down to examine the lid conjunctiva and fornix conjunctiva, noting its color, and whether it is clear and smooth, with or without congestion, edema, papillary hypertrophy, follicular hyperplasia, scarring, ulceration, lid bulb adhesions, and the presence of foreign bodies or secretion retention. To examine the bulbar conjunctiva, separate the upper and lower eyelids with the thumb and index finger and ask the patient to rotate the eyeball in each direction, observing for congestion, paying special attention to distinguish between ciliary congestion (which is around the cornea) and conjunctival congestion (which is in the peripheral part of the bulbar conjunctiva), and for herpes, hemorrhage, foreign bodies, hyperpigmentation, or neoplasia. (d) Eye position and movement Note whether the corneal position is in the center of the lid fissure when both eyes are looking straight ahead, whether the height is the same, and whether there is nystagmus and strabismus. The size of the eye is not abnormal and there is no protrusion or entropion. A simple way to detect protrusion is to sit the patient in a seated position with the head slightly tilted back and the examiner standing behind the patient, using both index fingers to simultaneously raise the patient’s upper lid and see if the protrusion of the two eyes is symmetrical from the back up to the front down. To accurately measure the normal anterior-posterior position of the eye and to record the degree of protrusion, a Hertel protrusion meter is used, in which the ends of the protrusion meter are stuck on the lateral orbital rim of the patient and the patient is asked to look forward and read from the reflector of the meter the number of mm of corneal apex projected on a scale (Figure 3-7). The normal average of the prominence of our eyes is 12-14 mm, and the difference between the two eyes is not more than 2 mm. When examining eye movements, the patient is asked to look up and down to the left and right, right, left, and left in eight directions to understand whether there is any obstruction to the rotation of the eye in each direction. (V) Orbital Observe whether the orbits on both sides are symmetrical and whether there is any defect, pressure pain or swelling on palpation of the orbital rim. A simple method of examining the anterior segment of the eye is the oblique illumination method, in which a flashlight with a spotlight bulb is held from the side of the eye at a distance of approximately 2 cm from the eye, and a 13D magnifying glass is held in front of the eye to examine the cornea, anterior chamber, iris, and lens. (a) Cornea Note the size, curvature, transparency and smoothness of the surface of the cornea. The presence of foreign bodies, neovascularization and clouding (scarring or inflammation). How does it feel. The presence or absence of posterior corneal precipitate (keratic precipitate, KP). Corneal fluorescein staining: In order to find out whether there is a defect in the corneal epithelium and whether the corneal opacity is ulcerated, a sterile glass rod with sterile 1% to 2% sodium fluorescein solution can be applied to the conjunctiva of the inferior fornix and observed after 1 to 2 minutes, the yellow-green staining can show the site and extent of the epithelial defect. Corneal curvature examination: The easiest way is to observe the distortion of the Placido plate on the cornea. The examinee is asked to sit backlit, and the examiner holds the plate in one hand, with the front of the plate facing the lid fissure, and observes the image of the black and white concentric circles on the cornea through the central hole in the plate. A normal image is a regular and clear concentric circle, an ellipse indicates regular astigmatism, and a distortion indicates irregular astigmatism (Figure 3-8). To determine the radius of curvature and refraction of the cornea for spectacles, refractive surgery or IOL implantation, a keratometer or corneal topography is required. Corneal sensory examination: A simple method is to twist a fiber from a sterile cotton swab and touch the cornea with its tip from the side of the subject, if it does not cause a transient reflex or if there is a significant difference in the required tactile force between the two eyes, it indicates decreased corneal sensation, which is mostly seen in people with herpes virus-induced keratitis or trigeminal nerve damage. (b) Sclera Note the presence of yellow staining, congestion, nodules and pressure pain in the sclera. （If the nasal iris is fully illuminated, it is a deep anterior chamber. If the nasal iris is only illuminated by 1 mm or less, it is a shallow anterior chamber and there is a potential risk of closed angle glaucoma. Note whether there is clouding of the atrial fluid and whether there is blood and pus accumulation in the anterior chamber. (d) Iris Observe the color, texture, presence of neovascularization, pigment detachment, atrophy, nodules, adhesions to the anterior cornea, adhesions to the posterior lens, root disconnection and defects, and tremor (lens dislocation). (e) Pupils: Are the pupils on both sides equal in size and round in shape, are they centered, and are the edges neat. The normal adult pupil is about 2.5 to 4 mm in diameter under diffuse natural light, and slightly smaller in young children and the elderly. Inspection of the pupil and various reflexes is of great significance for the diagnosis of visual pathways and systemic diseases, and is described below. 1. Direct-to-light reflex The pupil of the eye is rapidly narrowed in response to shining a flashlight on the eye in a dark room. This response requires the joint participation of the afferent and efferent nerve pathways of the pupillary reflex of the eye. 2. Indirect light reflex A response in which the pupil of the examined eye is rapidly narrowed when a flashlight is shone on the other eye in a dark room. This response only requires the involvement of the efferent pathway of the pupillary reflex of the examined eye. 3. Relative afferent pupillary defect (RAPD), also known as Marcus-Gunn pupil (Figure 3-9), is a condition in which the pupils of both eyes narrow when the right (healthy) eye is illuminated with a flashlight. The pupils of both eyes do not narrow because of afferent pupillary disorders in the left eye; when the pupils of the healthy eye narrow and the pupils of the affected eye dilate when the flashlight is shone alternately on both eyes at 1-second intervals. This sign is particularly helpful in the diagnosis of ocular diseases such as retrobulbar optic neuritis in one eye. 4, the pooling reflex first asked the subject to look at a distant target, and then changed to look at the 15-cm visual mark, then the pupils of both eyes narrowed, accompanied by bilateral pooling. 5, Argyll-Robertson pupil The direct light reflex disappears and the convergence reflex exists, this sign can be seen in neurosyphilis. (f) Lens Observe the lens for clouding and dislocation. Slit-lamp microscopy 1, slit-lamp microscope (slit-lamp biomicroscope) and use It consists of two systems, namely, the light source projection system for illumination, and the magnification system for observation. It can be used to examine ocular lesions by magnifying 10-16 times under strong light, which can not only make superficial lesions seen very clearly, but also adjust the focus and the width of the light source to form an optical section to identify deep tissue lesions and their anterior and posterior locations. Additional anterior mirror, contact mirror, anterior chamber angle mirror, triple mirror, can also examine the anterior chamber angle, vitreous and fundus. Then equipped with anterior chamber depth meter, pressure leveling IOP meter, camera, etc., its use is more extensive. 2, operation method Slit lamp microscope operation methods are many, commonly used is the direct focus illumination method, that is, the light focus and microscope focus joint together, the light will be projected on the conjunctiva, sclera or iris, visible a realm of clear illumination area, in order to fine observation of the lesion in the area. The slit light is shone on the transparent cornea or lens as an opalescent optical cut. This allows observation of its curvature, thickness, the presence of foreign bodies or posterior corneal deposits, and the level and shape of infiltrates, ulcers, and other lesions. By shifting the light into a small column into the anterior chamber, we can check for atrial water flash, also known as Tyndall’s phenomenon, which is an increase in protein in the atrial water and a milky white band of light between the cornea and the lens, as well as the presence of cells in the atrial water. Moving the focus backward also allows observation of the lens for clouding and the level of clouding, as well as lesions in the anterior 1/3 of the vitreous. To observe lesions in the posterior pole of the eye, an anterior lens can be used, paying attention to the angle between the projected optical axis and the visual axis within 30 degrees. In order to detect and examine certain special signs, sometimes the scattered illumination method of the corneal edge and the posterior reflection illumination method can also be used. Anterior chamber angle microscopy (a), anterior chamber angle and anterior chamber angle mirror 1, the anterior chamber angle by the anterior wall, the posterior wall and the two walls of the crypt composed of three parts. (1) The anterior wall is the most anterior Schwalbe line, the termination of the posterior elastic layer of the cornea, white, shiny, slightly raised; followed by the trabecular meshwork, pigmented, is the atrial drainage pathway, the scleral venous sinus is located on the outside of it; the end of the anterior wall is the scleral prominence, white. (2) The saphenous fossa is the anterior end of the ciliary body, which is black and also called the ciliary band. (3) The posterior wall is the root of the iris. 2, anterior chamber angle microscopy (gonioscope) The various structures of the anterior chamber angle must be detected by refraction (direct atrial angle microscopy) or reflection (using indirect atrial angle microscopy with slit lamp microscopy) of light using an anterior chamber angle microscope (Figure 3-11). Anterior chamber angle microscopy is a common method used in glaucoma prevention and treatment. In addition, anterior chamber angle microscopy must also be applied in order to detect lesions such as fine foreign bodies, neoplastic and neovascularization in the anterior chamber angle. (2) Clinical description of anterior chamber angle width and opening and closing Judging the width and opening and closing of the anterior chamber angle is important for the diagnosis, classification, treatment and prevention of glaucoma. 1.History The early description was proposed by Scheie, and thereafter for Shaffer’s classification, which focused on evaluating the geometric angle of the atrial angle and was divided into 5 levels and took into account the potential closure of the atrial angle, and was widely used because it was relatively simple. Finally, Spaeth proposed a more complex classification method that emphasized the three-dimensional structure of the atrial horn. 2, common atrial angle classification method (1), Scheie’s classification method: emphasizing the structure of the last part of the atrial crypt that can be seen microscopically, the narrow grade IV atrial angle is the narrowest. Those who can see all the structures of the atrial angle when the eye is in situ (static) are considered to have a wide angle, otherwise they are considered to have a narrow angle, and the narrow angle is further divided into four classes, i.e., those who can only see part of the ciliary band at static are considered to have a narrow Ι, those who can only see the scleral prominence are considered to have a narrow Ⅱ, those who can only see the anterior trabeculae are considered to have a narrow Ⅲ, and those who can only see the Schwalbe line are considered to have a narrow Ⅳ. Under dynamic, that is, the opening and closing of the atrial angle can be judged when changing the position of the eye or applying little pressure, if the posterior trabeculae are visible then the atrial angle is open, otherwise the atrial angle is closed. (2) Shaffer’s classification: The atrial angle is divided into 5 levels according to the width of the angle formed between the anterior surface of the iris and the inner surface of the trabecular meshwork under static examination. level 0 is the narrowest and level 4 is the widest. level 4 angle (35°~40°), all atrial angle structures are visible; level 3 angle (20°~35°), structures above the scleral eminence are visible; level 2 angle (20°), trabecular structures are visible; level 1 angle (10°) Atrial angle closure is not likely to occur in grade 3 to 4 of the Shaffer classification; grade 2 atrial angle may be closed; grade 1 atrial angle is likely to be closed. grade 0 to 1 are high-risk atrial angles; grade 2 should be followed up regularly. (3), Spaeth’s classification: evaluation of the anterior atrial angle according to three parameters by code: (1) atrial angle crypt angle width: evaluation of the atrial angle crypt width from 0° to 40° (0°, 10°, 20°, 30°, 40°) based on Shaffer’s classification; (2) peripheral iris morphology: code S (Steep) indicates bowed forward elevation morphology, r (Regular) indicates regular flat form, and q (queer) indicates irregular depressed form. The latter is commonly seen in eyes with pigment spreading syndrome, high myopia, lens dislocation, or aphakia. (3) Iris root attachment site (seen on dynamic examination): code A: at or before the Schwalbe line; code B: on the trabecular meshwork after the Schwalbe line; code C: on the scleral crest; code D: anterior to the ciliary body band; code E: posterior to the ciliary body band. spaeth’s classification is easy to make shorthand and evaluate the anterior chamber angle, e.g., E-40°-q: extremely wide anterior chamber angle, open angle; D-10°-S: extremely narrow anterior atrial angle, iris bulge, but open atrial angle; B-40°-r: wide anterior atrial angle, flat iris, but atrial angle may be closed. (C), trabecular meshwork pigment grading The trabecular meshwork pigment is divided into 5 grades: Grade 0: trabecular meshwork lacks pigment particles; Grade I: fine pigment particles are distributed on the posterior trabecular meshwork; Grade II: both anterior and posterior trabecular meshwork have fine pigment particles; Grade III: dense rough granular or homogeneous black or tan pigment is attached to the posterior trabecular meshwork, and pigment particles can also be seen on the anterior trabecular meshwork and Schwalbe’s line Grade IV: homogeneous black or tan pigmentation over the entire trabecular meshwork, with pigment particles visible on the Schwalbe line, scleral crest and inner surface of the cornea, ciliary body band and scleral surface. IOP measurement (tonometry) includes finger-measurement and tonometer measurement. (a) Finger-prick method is the simplest method to estimate IOP qualitatively, and requires some clinical experience. The patient is instructed to gaze down at both eyes while the examiner places the tips of the index fingers of both hands on the skin surface of the upper eyelid and alternately presses lightly on the eyeball, feeling the tension of the eyeball as if it were fluctuating, to estimate the hardness of the eyeball. Beginners can touch their forehead, nose tip and lips to roughly feel the 3 types of IOP: high, medium and low. When recording, use Tn to indicate normal IOP, T+1 to T+3 to indicate the degree of increased IOP, and T-1 to T-3 to indicate the degree of slightly lower IOP. (B), the ophthalmometer measurement method ophthalmometer is divided into flattening type, indentation type two types. (1), indentation type: such as Schiotz IOP meter, is to use a certain weight of the IOP measuring rod to make the cornea into a depression, under the condition that the weight of the IOP meter remains unchanged, the deeper the indentation the lower the IOP, and its measurement value is affected by the hardness of the wall of the eye. (2), flattening type: is used with sufficient force to flatten the cornea, according to the area of the cornea flattening or pressure size can be divided into two kinds. One is a fixed flattening area, depending on the size of the force required to flatten the area, the force required is small, the IOP is also small. When a flattening tonometer measures IOP, the convex surface of the cornea flattens slightly without sinking, and the volume of the eye changes very little, so it is not affected by the hardness of the eye wall, such as the Goldmann flattening tonometer. Another type of fixed pressure (the weight of the tonometer remains unchanged) depends on the flattening area, the larger the flattening area the lower the IOP, such as Maklakow flattening tonometer, this kind of tonometer measurement of the volume of the eye has a greater impact, the measured IOP value is affected by the hardness of the eye wall. 1.Schiotz IOP meter is still widely used in China. This ophthalmometer is indentation type, and the amount of its scale depends on the degree of pressure of the ophthalmometer needle on the downward depression of the cornea, so the measured value is influenced by the hardness of the bulbous wall. In cases of significant abnormalities in spherical wall hardness (e.g., highly myopic eyes), a low number is given, and the error caused by spherical wall hardness can be eliminated by using two weights for measurement and then checking the table for correction (Figure 3-13). 2, Goldmann pressure flattening IOP meter This is the current international standard IOP meter, which is attached to a slit lamp microscope, observed with a microscope and measured in a sitting position (Figure 3-14). It is a pressure flattening tonometer, which only flattens the cornea without sinking during measurement, so it is not affected by the hardness of the spherical wall. However, recent studies have found that the thickness of the central cornea affects the IOP values it measures. If the central cornea is thick, the IOP value is overestimated, and if the central cornea is thin, the IOP value is underestimated. perkin IOP meter is a hand-held flattening IOP meter that does not require a slit-lamp microscope for examination, and the subject can be in a sitting or lying position. The principle of non-contact tonometer is to use controlled air pulses with a linear increase in pressure to flatten the cornea to a certain area, feel the light reflected from the corneal surface through the monitoring system, record the time when the cornea is flattened to a certain level, and convert it into IOP value. The advantage is that it avoids cross-contamination caused by the contact of the tonometer with the cornea and can be used for patients who are allergic to corneal surface anesthetics. The disadvantage is that the measured value is not accurate enough. The commonly used ophthalmoscope has two types: direct and indirect (Figure 3-15, Figure 3-16). (a), direct ophthalmoscope examination The fundus is seen as a positive image, put about 16 times. Usually the pupil can be examined without dilatation, but if a detailed examination is needed, the pupil should be dilated. The order and content of the examination are as follows: 1. The thorough illumination method is used to observe the refractive interstitial clouding of the eye. When normal, the pupil area is an orange-red reflection, if the refractive interstitium is cloudy, a black shadow appears in the red reflection; at this time, the patient is asked to turn the eye, and if the black shadow moves in the same direction as the eye movement, it indicates that the cloudiness is located in front of the lens, and vice versa, it is located behind the lens, and if it does not move, it is in the lens. 2, fundus examination Dial to “0”, 2cm from the examined eye, because the examiner and the refractive state of the examined person is different, need to dial the dial to see the fundus until. Ask the patient to gaze straight ahead, the light source of the examining glass through the pupil deviated nasal side about 15 ° can check the optic disc, and then along the vascular direction to observe the peripheral part of the retina, and finally ask the patient to look at the light of the examining glass, in order to check the macula. 3. Fundus examination records: size and shape of the optic disc (whether there is congenital developmental abnormality), color (whether there is optic nerve atrophy), boundary (whether there is optic disc edema, inflammation) and pathological depression (glaucoma); size, uniformity, color, arteriovenous ratio (normal 2s3), shape, pulsation and cross-compression of retinal vessels; macula and central concave light reflection; whether there is retinal hemorrhage The retina should be described for hemorrhage, exudation, pigmentation or loss, and its size, shape and number. The obvious abnormalities can be plotted on the retinogram. (b), binocular indirect ophthalmoscopy Indirect ophthalmoscopy has a small magnification, a large visible range, the image seen is inverted, with a sense of stereo, generally need to dilate the pupil examination. The field of view seen with indirect ophthalmoscopy is larger than that of direct ophthalmoscopy, which can observe the fundus more comprehensively and is not easy to miss fundus lesions. Supplemented with a scleral compressor, the serrated edge can be seen, which is conducive to finding retinal fissures. Because it can examine the fundus at a longer distance, operations such as retinal fissure closure and extra-scleral pad pressure can be performed under direct vision. It is mainly used for: (1) all kinds of primary and secondary retinal detachment; (2) all kinds of fundus disorders caused by uneven elevation, such as swelling, inflammation, exudation and parasites; (3) intraocular foreign body when the refractive medium is transparent, especially the foreign body in the flat part of the ciliary body; (4) the refractive medium is unclear or high refractive error, and it is difficult to observe the fundus with direct ophthalmoscopy. Fundus angiography Fundus angiography is the process of injecting contrast agent into the body from the elbow vein and using a fundus camera with a specific filter to photograph the fundus vessels and their perfusion. It can be divided into two types of fundus fluorescence angiography (FFA) and indocyanine green angiography (ICGA), the former is using sodium fluorescein as the contrast agent, mainly reflecting the condition of retinal vessels, and is a common and basic fundus angiography method (Figure 3). The former uses sodium fluorescein as the contrast agent and mainly reflects the retinal vasculature, which is a common and basic method of fundus angiography (Figure 3-17); the latter uses indocyanine green as the contrast agent and reflects the choroidal vasculature, which aids the former in detecting early choroidal neovascularization, leakage, etc., because the choroidal vascular image appears in FFA for only a few seconds and is quickly obscured by the retinal vascular image. The normal human arm-retinal circulation time is about 7 to 12 s. Staging of fluorescein fundus angiography vascular filling: divided into pre-retinal arterial (early fluorescence of the optic papilla → arterial laminar flow), arterial phase (arterial laminar flow → arterial filling), arteriovenous phase (arterial filling → venous laminar flow) and venous phase (venous laminar flow → venous filling), and late phase (about 5 to 10 minutes after fluorescein injection). Abnormal fundus fluorescence patterns: 1. Strong fluorescence (1), transillumination fluorescence: seen in retinal pigment epithelial atrophy and congenital pigment epithelial reduction. Characteristics: (1) It appears in the early phase of fluorescence imaging, fills with the choroid at the same time, and diminishes or disappears with the emptying of choroidal dye in the late phase of imaging. (2) The morphology and size of its fluorescence do not change in the late contrast phase. (2), abnormal vessels and their anastomoses: such as tortuous dilatation of vessels, microaneurysms, commonly retinal vein obstruction, diabetic retinopathy, retinal adventitia, congenital vasodilatation, optic papilledema, optic papillitis, etc. (3), neovascularization: it can occur in the retina, subretina or optic disc, and can enter the vitreous. Neovascularization can cause fluorescein leakage. Retinal neovascularization is mainly caused by retinal ischemia, most commonly in diabetic retinopathy, retinal vein obstruction, retinal perivasculitis, etc. Some lesions can cause choroidal neovascularization, such as age-related macular degeneration. (4) Retinal leakage: The result of disruption of the retinal vascular endothelial and pigment epithelial barriers and leakage of dye into the tissue interstices. Characteristically, it appears late in the contrast phase. Macular vascular leakage is often manifested as cystic edema. (5) Choroidal leakage: divided into pool-like filling and tissue staining. (1) Pooling is also known as pooling, in which the fluorescence pattern and brightness become larger and stronger with the progress of time, and the fluorescence is maintained for several hours. Fluorescein accumulates under the retinal sensory layer (border unclear) and under the pigment epithelium (border clear). ② tissue staining (staining), which means that abnormal structures or substances under the retina can be stained by choroidal leakage, resulting in late strong fluorescence, such as vitreous wart staining, macular scar staining. 2, weak fluorescence (1), fluorescence masking: the part that should show fluorescence under normal circumstances, due to the presence of cloudy substances on it, such as blood, pigment, so that the fluorescence is significantly weakened or disappeared. (2), vascular filling defect: low fluorescence due to vascular obstruction, no fluorescence filling in the blood vessels. Such as pulseless disease, carotid artery stenosis, ophthalmic artery or central retinal artery obstruction. Retinal venopathy can result in poor venous filling. If capillary occlusion can form a large dark area without fluorescence, called non-perfusion area, commonly seen in diabetic retinopathy, after retinal vein obstruction, etc. Ophthalmic imaging has developed rapidly in recent years, and has gradually become a common method for clinical diagnosis of ophthalmology. Here we only outline the examination principles and indications. (A), ocular ultrasonography Ophthalmology commonly used ultrasound scanner is divided into type A and type B. In recent years, color ultrasound Doppler has been used in ophthalmology. 1, type A ultrasound: shows the detection of the echoes of each acoustic interface of the tissue, in the form of wave crests, in order of the time sequence of the echoes returned to the probe on the baseline, constituting a one-dimensional image consistent with the direction of detection. The advantages are accurate distance measurement and quantification of the strength of the echoes, B-type ultrasound scanning: through the sector or line array scanning, the interface reflected echoes into the form of light dots of different sizes and brightness, light dots represent the strength of the echoes, echo formation of many light dots on the oscilloscope screen to form a two-dimensional acoustic section of the local tissue image. Real-time dynamic scanning can provide the location, size, morphology and relationship with surrounding tissues of the lesion, and obtain an intuitive and practical impression of the detected lesion. (Figure 3-18) 2. ultrasound biomicroscopy (UBM) UBM is also a type of B-mode ultrasound, with the difference that the frequency spectrum of the UBM transducer is high, generally above 40 mHz. Therefore, compared with ordinary 2D ultrasound, it can obtain clearer images and more detailed observation of tissue structures, and can obtain image characteristics similar to those of low magnification optical microscopy. Its limitation is that the penetration is weak, and the general imaging range is between 5mm×5mm and 8mm×12mm, so only the anterior segment of the eye can be examined. Indications: ① Patients with glaucoma can apply UBM to understand the atrial angle exhaustively. ② To understand the damage of the anterior segment in case of ocular trauma, such as low intraocular pressure syndrome, foreign body, etc. (iii) Morphological observation of tumors in the anterior segment of the eye. ④Diagnosis of peripheral vitreous and ciliary body diseases. Examination of posterior iris structures is a feature of UBM, which is the only examination method among existing instruments and equipment that can understand the posterior chamber and ciliary body in the in vivo state. ⑤ Corneal and conjunctival diseases, anterior segment scleral diseases, and lens diseases can also be examined by UBM. . Color doppler imaging (CDI) is a technique that uses the Doppler principle to superimpose blood flow characteristics in color on a B-shaped gray-scale map, with red indicating blood flow toward the probe (often an artery) and blue for blood flow behind the probe (often a vein). often a vein). The blood flow color is used as an indication for localization, sampling and quantitative analysis. It can detect blood flow in the ophthalmic artery, central retinal artery, posterior ciliary artery, and intraocular and intraorbital tumors. Indications: ; ② intraocular tumors;; ④ etiological diagnosis of ocular protrusion; ⑦ ocular and orbital hemodynamic studies (CDI); (b), electronic computed tomography (computer tomography, CT) The use of ionizing rays and the assistance of a computer to form multiple cross-sectional images. It can be used to observe soft tissue or bony structures. The layer thickness of each scan is usually 1 to 2 mm. contrast can be used for the assessment of vascular structures, and significant leakage can occur when the barrier effect of normal capillaries is disrupted. indications for CT scan: ① suspected intraocular tumors; ② orbital lesions including tumors, acute and chronic inflammation and vascular malformations; ③ ocular trauma orbital bone fractures; intraocular and intraorbital foreign bodies, both metallic and non-metallic, can be displayed and localized; ④ unexplained visual impairment, visual field defects, etc. (iv) unexplained visual impairment, visual field defects, etc. to explore the optic nerve and intracranial occupational lesions. Methods: CT orbital examination requires both cross-sectional and coronal scans. The plain scan is routinely performed. The baseline is the infraorbital line (the line between the inferior edge of the orbit and the center of the external auditory canal). The coronal scan can be performed in the supine or prone position, generally in the supine position, with the head in the supine chin position, with the mid-sagittal plane of the head perpendicular to the examination bed, and the scan baseline is the vertical line of the infraorbital line. The cross-sectional scan should cover the orbital apex to the orbital floor, and the coronal scan should cover the entire orbit from the eyelid to the pterygoid area. For orbital wall fracture observation, a bone window with bone algorithm reconstruction and a soft tissue window at the fracture level is generally used; for soft tissue structure observation, a soft tissue window scan is mostly used and a bone window at the lesion level is reconstructed. For optic nerve canal examination, a bone window scan was used. Multi-layer spiral CT examination acquires mostly volumetric data, which can be reconstructed in coronal and sagittal positions for multi-directional observation. (3), magnetic resonance imaging (MRI) (1), the basic principle: MRI is the use of hydrogen atoms in the human body in a strong magnetic field by the frequency of radio frequency pulse excitation, the proton absorption energy resonance. After the termination of the RF pulse the protons release energy when they return to their original state, i.e., the MR signal, which is passed through the receiving coil, received and converted into an MRI image by a computer. T1-weighted imaging (T1WI) means that this imaging method focuses on the longitudinal relaxation differences of the tissue and minimizes the effect of other tissue properties such as transverse relaxation on the image; T2-weighted imaging (T2WI) focuses on the transverse relaxation differences of the tissue. Basic examination methods: Cranial coil or ocular surface coil is used. Ocular surface coils can be used for lesions of the eye. The ocular surface coil has a small field of examination, high signal-to-noise ratio, high image resolution, and shows anatomical details more clearly, but it is sensitive to eye movements, especially T2WI has more movement artifacts. Orbital and retrobulbar lesions are examined using cephalometric coils, which have a large field of view and are useful for understanding the relationship between the lesion site and adjacent structures, and are especially valuable for cranio-orbital communicating lesions. Ocular MRI scans are performed in cross-sectional, coronal and oblique sagittal planes with the same baseline as the CT scan baseline. T1WI and T2WI scans are usually performed in the cross-sectional plane, and T1WI scans are performed in the remaining sections. Gd-DTPA 0.1 mmol/kg is used as the contrast agent for MRI enhancement, and the largest section is usually selected for dynamic enhancement, followed by SE sequence T1WI for all three sections, and fat suppression scan can be added to the section with the clearest lesion. Intravenous injection of Gd-DTPA and fat suppression technique can improve the contrast between the tumor and the surrounding tissues and make the lesion appear clearly. (2) Indications: All kinds of ocular and orbital lesions (except metallic foreign bodies) that need to be displayed by imaging are indications for MRI. (1) Diagnosis and differential diagnosis of intraocular tumors. (2) Intraorbital tumors, especially small orbital apical tumors and optic nerve tumors, showing tumor invasion in the optic nerve canal and intracranial segment MRI is better than CT. (3) Acute and chronic inflammation in the orbit. ④Vascular malformation in the orbit. ⑤ Chronic orbital trauma. (6) Intracranial spread of intraorbital masses and intraorbital invasion of periorbital masses. (7) Certain neuro-ophthalmologic diseases. (3) Contraindications: those with pacemakers and nerve stimulators; those with artificial heart valves; post-operative arterial silver clips; those with metal prostheses implanted in the inner ear; those with metal foreign bodies. (D) Ophthalmic computer image analysis The application of computer image processing, scanning confocal laser and other technologies is an important symbol of modern ophthalmology development, providing a more sophisticated examination method for ophthalmology diagnosis and research, introduction as follows: . Optical coherence tomography (OCT): It is a new non-contact non-invasive optical imaging diagnostic technique developed in the early 1990s, which uses the different reflectivity of different tissues in the eye to light (with 830 nm near infrared light), and compares the reflected light waves with the reference light waves through a low coherence optical interferometry to The delay time and reflection intensity of the reflected light waves are measured, and the structures of different tissues and their distances are analyzed and imaged by computer processing, and the cross-sectional structures of the tissues are displayed in pseudo-color. The axial resolution can reach 10 μm. it has important application value for the diagnosis of macular diseases. However, the resolution of OCT relies on the different reflective properties of tissue structures to distinguish tissues, and the really easy to distinguish clearly in retinal tomography are neuroepithelial light bands, pigment epithelial light bands and choroidal light bands, and the structures between neuroepithelial layers are still difficult to distinguish clearly. There are horizontal, vertical, circular, radial, and linear scans with different angles, and the examiner can choose the appropriate scan according to the location, nature, and purpose of the lesion. Because the lateral resolution of OCT is related to the length of the scan line, the longer the scan line, the lower the resolution. In order to facilitate the comparison of information and the standardization of data acquisition, a fixed scan length and a fixed scan sequence can be selected. For example, for macular scans, a linear scan with a scan line length of 4 mm or 4.5 mm and 45° interval can be selected as the basic scan. Corneal topography (corneal topography) is also known as a computer-aided corneal topography analysis system. It is a computerized image processing system that digitally analyzes the corneal morphology and then presents the obtained information in a color morphological map with different characteristics, which is called corneal topography because it resembles the undulating state of the earth’s surface in geography. Corneal topography allows the detection of most of the corneal refractive power from the central to the peripheral part of the cornea, thus allowing a greater amount of information to be obtained, which is clinically important in the detection of corneal refractive power. The corneal topography of normal corneas is generally steep in the center and flattens out toward the periphery, with most corneas being approximately 4.00D flat; for the same individual, the corneal topography is often similar, but for different individuals, the corneal topography is often different from each other; the corneal topography of normal corneas can be divided into the following categories: round, oval, symmetrical or asymmetrical bowtie (or figure of eight), and Irregular shape. Corneal endothelioscopy is the use of light shining on the interface of the cornea, lens and other transparent refractive components to reflect, between the corneal endothelium and the atrial fluid interface, the intercellular space will reflect and form dark lines, thus showing the mosaic hexagonal appearance of corneal endothelial cells. Modern corneal endothelial microscopy is combined with a computer to automatically analyze corneal endothelial cell morphology. The corneal endothelioscopy method is divided into contact and non-contact types. The commonly used non-contact endothelioscope is used to see the corneal endothelial cell morphology when the illumination optical axis of the slit lamp microscope and the observation axis are symmetrically separated from the corneal apex vertical line to both sides. The condition of the corneal endothelium is closely related to corneal nutrient metabolism and facilitates the evaluation of corneal endothelial function. In normal people, the average cell density is 3,000 to 4,000 cells/mm2 before the age of 30, 2,600 to 2,800 cells/mm2 around the age of 50, and 2,150 to 2,400 cells/mm for people older than 69. Corneal confocal microscopy Using confocal laser to scan the living cornea at different levels, it can show the ultrastructure of the cornea and assist in the diagnosis of fungal and amebic keratitis. Scanning laser polarimetry uses two beams of polarized laser light perpendicular to each other to scan the retinal nerve fiber layer (RNFL) around the optic disc, the light reflection parallel to the RNFL alignment is faster than the light reflection perpendicular to the RNFL, the time difference between the two reflections is called the polarization The difference in time between the two reflections is called the polarization delay value, which indirectly reflects the thickness of the RNFL and aids in the early diagnosis of glaucoma. Scanning laser topography uses a confocal laser to scan the optic disc at 32 levels, giving a three-dimensional picture of the topography of the optic disc surface and automatically detecting several parameters related to the optic disc, optic cup and disc rim for early diagnosis of glaucoma and follow-up monitoring of the optic nerve.