in Slit Lamp

Slit lamp microscope

Brief introduction
Slit lamp microscope, ophthalmic examination is an indispensable instrument. Slit lamp microscope binocular microscope by the illumination system and composition, it can not only make superficial lesions observed very clearly, and can adjust the focus and the light source width, made “optical section” to make deep tissue lesions can clearly show .

Slit lamp microscope
Working principle
As the name suggests it is the light through a crack on the eye for lighting. Because it is a slit light source, so it is called “knife.” This “knife” is irradiated to form an optical section eye, can be observed in various parts of the health of the eye. Its principle is to use the British physicist John Tyndall’s “Tyndall phenomenon.”
Tyndall phenomenon: when a beam of light through a colloid, from the vertical direction of the incident light can be observed a bright “path” colloid appeared, this phenomenon is called Tyndall phenomenon, also known as Tyndall effect.
Our daily lives see this phenomenon: The beam of a flashlight at night; the sun through a window or door inside the house irradiation; forest sunlight and so on. In order to effectively observe the health of the eye, slit lamp must be installed in a relatively dark room light, the light source illuminates the eye fissure, then the examining physician to observe the health of the various parts of the eye through a microscope.

The basic structure
Slit lamp constructed mainly consists of two parts, namely “slit lamp” and “microscope.” In order to facilitate fracture eye light source of each part from different angles, as well as microscope eye from different angles, the requirements on the mechanical slit lamp microscope has sufficient swing angle. Slit lamp light source requires its fractured edges must be very smooth, crack must clear image in the center vertical plane from side to side, while the focus of the microscope must also be focused on the center vertical plane.

Digital Slit Lamp

Fractured lighting must have:
1. crack width in the range of 0 to 14mm adjustable;
2. crack length adjustable (when the length and width are 14mm fracture when light is actually a circular spot) in the range of 1 to 14mm. ;
3. direction fractures adjustable. That source may be vertical cracks, it can be horizontal, but may be oblique;
4. adjustable brightness light source;
For digital photographic slit lamp should have adjustable brightness backlight light.
Stereo binocular microscope structure, must have:
1. a clear image;
2. adjustable eyepiece focal length to accommodate different operator diopter;
3. adjustable distance between the two eyepieces to accommodate different operator IPD;…
In addition to the above-mentioned mechanical structure of the swing function, but also with three adjustable moving platform; jaw holder means can be fixed patient head, adjustable upper and lower jaw jaw holder rack to accommodate different patient’s skull length; fixation lamp can avoid the patient’s eyes unconsciously rotated.

Common auxiliary instruments slit lamp microscope
1. Gonioscope
2. Corneal thickness gauge
3. Laser photocoagulation apparatus
4. Retinometer meter

When using diffuse illumination method using a collection of light, low magnification, can cornea, iris, lens for a comprehensive observation.
When the direct focus illumination method can be observed curvature and thickness of the cornea, with or without foreign bodies and corneal deposits (KP), and infiltration, ulcers and other disease levels and forms; the focus is pushed back, the crystal can be observed as with the light cone, you can check the price of water floating particles; turbid and the front part of vitreous 1/3.
When irradiated with a mirror reflection method, you can carefully observe the subtle changes around the cornea and lens capsule before and after, such as tear film exfoliated cells, patterns, crystal pattern around the capsule and adult nucleus of the corneal endothelium.
When using a rear reflector irradiation, can be found in epithelial or endothelial corneal edema, corneal calm things, angiogenesis, mild scarring, as well as crystal and other cavity.
When the horn Gong fate lighting method, you can find a very light haze on the cornea, such as nebula, blisters, piercing, scars and so on.
When indirect illumination method can be observed pupil sphincter, iris hemorrhage, iris blood vessels, cornea pannus like. Meanwhile slit lamp microscope can also attach pre-mirror, and three-mirror contact lens, etc., with peripheral retinal examination, anterior chamber and vitreous rear, can produce more by binocular stereo vision.
Therefore, by slit lamp examination, wearing soft contact lenses can be identified contraindications for wearers of soft contact lens fitting option.

Care and maintenance
1, slit lamp microscope is a precision instrument, under normal circumstances, the instrument should be placed in a well-ventilated, dry environment, the relative humidity should not exceed 50% of the interior, otherwise plated metal parts and optical parts of the surface of the instrument have adverse effects .
2, slit lamp Microscope optics is a key instrument to ensure the normal use, be sure to keep clean. When the lens from dust, spare parts are available random pen whisk gently brushed the dust; if there is oil lenses, available cotton flower dipped in a mixture of 60 percent alcohol and gently wipe 40% diethyl ether to remove the oil.
3, the optical lens surface due basin to avoid contact with the hands and other parts of the body, because the body sweat and grease on the optical components will directly affect the quality of the surface; after contact with regret because if you do not operate it in order to ensure timely wipe clean the lens. can grow
Term use.

Vision problems in space travelers inform eye health, disease research
4, above the instrument easy to plot the dust the condenser, remove the lamp cover and lamp holder, with pen whisk gently brushed the dust in order to ensure normal operation of the instrument in the quality of the light source.
5, Killeen proud axis motion base of the instrument on the outside part should be regularly wiped clean and evenly coated with a very thin layer of oil, so that it remains smooth; otherwise rust or dirt contaminated with a direct impact on the instrument flexible operation.
6, when moving the instrument should be sports base, slit lamp microscope arm and the arm of the fastening bolt tightened to prevent the instrument from the instrument when carrying out rail or the instrument lost focus. Broken instruments. In normal use these instruments should be three bolts loose.
7, the instrument after use, should be promptly put leather dust outside of the instrument. Instrument to prevent dust and dirt.
8, optical instruments and spare parts (accessories) should be stored in a cylinder filled with desiccant drying preservation.
9, before using the instrument Please note the local power supply fits this instrument of power requirements.

1. Focus: Focus instrument brought rod insertion position shown in the drawing, so that cracks at the center of focus according to the diameter of the rod, a clear crack tone light. Rotating eyepiece adjustment ring, if the microscopic eyepiece can clearly see the cracks and focus rod surface, indicating that the cracks and confocal microscopy.
2. by adjusting the level of the instrument station and the jaw holder and the level of the gantry system that allows the subject to sit
The comfort, the head is fixed to the jaw and forehead against the upper bracket, engraved contour line of the subject and the outer canthus on the column. If the instrument is not the focus can be moved to the bridge of the nose at the crack of patients focusing.
Slit lamp microscope using an optical principle
(1).Shines law
Slit lamp 450 to take the position, a front view of the microscope, which is the most common method. Shines with the law can be observed most immediate lesions, such as the proliferation of conjunctival papillae, conjunctival follicles, scarring trachoma, corneal foreign bodies, corneal clouding, anterior lens capsule and lens opacity pigments and the like. This method is mainly to check and change the color of the relevant part of the form to determine the lesion.
(2).Reflective law
Slit lamp shining into the eye cornea front face, back, front, crystal, behind other smooth surface, reflection phenomenon occurs when. At this time, such as the rotation of the microscope stand, the reflected light enters the microscope, then when observed with a microscope, one would have to see a very bright reflection. Microscope can move back and forth to see the fine changes reflective surface. If the rotation angle and the slit lamp microscope to change the irradiation site without moving the microscope, can also achieve the purpose of the reflected light (Note: The microscope must focus on reflective surfaces). When this law can be used to check the surface of the cornea corneal edema “seeding.” Corneal epithelial exfoliation, corneal ulcer healing scar, anterior lens capsule reflective or reflective color and so on.
(3).After irradiation method
AF method is basically the same method shines, but this time the observer not watch the illuminated mirror clearly at the border, and the line of sight to the iris, resulting in a blurred spot. Attention turned to the spot in front of the iris portion of the cornea observation, you will see appear on a bright background corneal disease. When corneal neovascularization or after deposits, deep corneal foreign bodies, corneal deep blood vessels, cornea pannus like. Such conditions can not confirm the diagnosis using shines method This method is used often easy to visit.
(4).Diffuse light illumination method
This way the light irradiation method: an illumination system from a larger fracture angle oblique projection, while fully open fracture, widely irradiation, or the use of concentrated light plus ground glass, low magnification microscope. Ordinary light illumination, if coupled with frosted glass, lighting is poor, difficult to observe subtle lesions. But with fractured illumination light, the light is highly concentrated, because light is too strong, not sustainable for a long time. Therefore, we can not add frosted glass, and then use to focus the light, and as short as possible to focus the light irradiation time. This method uses a high concentration of fractured light intensity, and the use of binocular vision at the same time check, so check in is very convenient, comfortable, easy to grasp; the observed morphology of the site intact, with three-dimensional. It is mainly used to check the situation conjunctiva, sclera, cornea, lens and other anterior segment tissue. For example, this method may be the entire cornea, iris, lens surface for a comprehensive observation, and three-dimensional; for corneal folds stretch film, the elderly form the lens capsule and lens nucleus like a complete concept than the average shines method is superior.
(5).Adjust aperture Usage
When adjusting aperture size can be obtained as different crack lengths it is generally used for sweeping the eye, an overview of ocular lesions. It may be appropriate to shorten the length of the crack as check crystal in order to reduce glare. When the contact lens or mirror with pre fundus examination or rear vitreous, like the crack length must be shortened. Blue filters commonly used in fluorescent observation, the green filter is used to observe the blood vessels.

Slit Lamp Exam (Video)

Clinical Significance
1. diffuse illumination method: Can cursory examination conjunctival and corneal sclera and other front organizations.
2. Direct black spots lighting method: the careful observation of illuminated area of the lesion.
3. The rear lighting method: the back of the organization for help to check the front of the reflected light is mainly used to check the tissue transparent organization.
4. specular reflection illumination method.
5. cornea fate lighting method.
6. The method of indirect lighting.

1911 Swedish scientist Gullstrand eye invented the famous eye examination instrument “slit lamp” (Slit lamp), 1920  vogt be improved to make it more perfect, became the blueprint for today’s slit lamp.
In 1950 China started to develop a slit lamp, 1967 Shanghai Medical Optical Instrument Factory lead a successful trial. The same year also successfully Suzhou Medical Instrument design and manufacture of a slit lamp, and in the next twenty years to become a major production of Chinese slit lamp manufacturers. Then this period the plant also launched a 135 film camera slit lamp. Since the film flush technology in ophthalmology and the hospital can not grasp the scope of which time the film is seriously lagging behind, hampered the development of photographic film slit lamp. Only in ophthalmology medical research, the paper compiled a small aspect of the application. And it has been in use in clinical eye observation, handwritten report inspection mode.
With the rapid development of market economy, the nineties slit lamp manufacturers have sprung up, the market competition is also heating up state. With the rapid development of computer technology, digital imaging technology, the new photographic slit lamp ever-changing. Wherein the highly regarded digital camera applications. Photos and text reports can be printed on one diagnostic report card on the inspection report can do that is to check that is out. Thus photographic slit lamp before entering the actual clinical application. Chinese slit lamp has been out of the country, a number of manufacturers have a lot of exports and export sales year after year highs.

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