Eye examination with side (focal) and transmitted light
Last reviewed: 19.10.2021
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The method is designed to detect subtle changes in the anterior part of the eyeball.
The study is conducted in a dark room using a table lamp installed on the left and front of the patient at a distance of 40-50 cm at the level of his face. For inspection use ophthalmic loupes with a force of 13.0 or 20.0 diopters. The doctor is located opposite the patient, his legs are to the left of the legs of the latter. Then the doctor takes the magnifying glass with his right hand, slightly turns the patient's head towards the light source and directs a beam of light to the eyeball. The magnifying glass should be placed between the light source and the patient's eye, taking into account its focal length (7-8 or 5-6 cm) so that the light rays, passing through the glass, are focused on a certain area of the anterior section of the eyeball to be examined. Bright illumination of this site in contrast with the neighboring makes it possible to examine in detail the individual structures. The method is called lateral, because the magnifier is located on the side of the eye.
In the study of sclera pay attention to its color and the state of the vascular pattern. Normally, the sclera is white, only the conjunctival vessels are visible , the marginal loopy network of vessels around the cornea is not visible.
The cornea is transparent, shiny, smooth, mirrored, spherical. Normally, there are no own vessels in the cornea. Through the cornea is seen the anterior chamber of the eye, the depth of which is better seen from the side. The distance between light reflexes on the cornea and iris determines the depth of the anterior chamber (normally its depth is 3-3.5 mm in the center). The moisture filling the front chamber is normally perfectly clear. With some diseases, it can contain pus, blood, flakes of exudate. Considering the iris through the cornea, note whether there are any changes in color and pattern, the presence of coarse inclusions of the pigment, assess the condition of the pigment fringe, the width and mobility of the pupil. The color of the iris depends on the amount of pigment in it and is from light blue to dark brown. The change in the color of the iris can be detected by comparing it with the color of the iris of the other eye. In the absence of pigment, the iris is transparent, it has a red color due to the translucence of the choroid (albinos). The lace-like appearance of the iris is attached to its trabecular and lacunar structure. In it the pupillary and root (ciliary) zones are distinctly distinguished. On the pupillary margin there is a brown border, which is part of the inner pigmentary leaf of the iris, turned out on its front surface. With age, this border is depigmented.
At lateral illumination the pupil is defined as a black circle. The pupil examination can be carried out using three methods: papilloscopy, papillomatometry and papillography, however in clinical practice the first two are usually used.
A study to determine the size (width) of the pupil is usually carried out in a bright room, while the patient looks afar over the doctor's head. Pay attention to the shape and position of the pupil. Normally the pupil is round, and in pathological conditions it can be oval, scalloped, eccentric. Its size varies depending on the illumination from 2.5 to 4 mm. In bright illumination, the pupil contracts, but expands in the dark. The size of the pupil depends on the age of the patient, his refraction and accommodation. The width of the pupil can be measured by a millimeter ruler, and more precisely by a papillometer.
An important property of the pupil is its reaction to light, I distinguish three types of reaction: direct, friendly, reaction to convergence and accommodation.
To determine the direct reaction: first, both eyes are covered with palms for 30-40 seconds, and then in turn are opened. In this case, the opening of the eye will show a narrowing of the pupil in response to the light flux entering the eye.
Friendly reaction is checked as follows: at the time of covering the opening of one eye, I observe the reaction of the second. The study is conducted in a darkened room using light from an ophthalmoscope or a slit lamp. When opening one eye, the pupil in the other eye will expand, and when it opens, it will narrow.
The pupil's response to convergence and accommodation is evaluated as follows. The patient first looks into the distance, and then looks at some close object (the tip of the pencil, the handle of the ophthalmoscope, etc.), located at a distance of 20-25 cm from it. In this case, the pupils of both eyes taper.
Transparent crystalline lens in the study using the method of lateral illumination is not visible. Particular areas of turbidity are determined if they are located in the surface layers: When the cataract ripens fully, the pupil becomes white.
Examination in Transmitted Light
The method is used to examine the optically transparent eyeballs (cornea, the anterior chamber, lens, vitreous humor ). Given that the cornea and anterior chamber can be inspected in detail with side (focal) illumination, this method is used primarily for the study of the lens and vitreous.
The light source is installed (in a darkened room) behind and to the left of the patient. The doctor with the help of a mirror ophthalmoscope, attached to his right eye, directs a reflected beam of light into the pupil of the patient's eye. For a more detailed study, the pupil should first be expanded with the help of medications. When a light beam hits, the pupil begins to glow red, which is due to the reflection of the rays from the vascular membrane (reflex from the fundus). According to the law of conjugate foci, some of the reflected rays fall into the eye of the doctor through an opening in the ophthalmoscope. In the event that in the path reflected from the fundus of the rays there are fixed or floating opacities, against the background of a uniform red glow of the fundus there appear fixed or moving dark formations of various shapes. If, in the lateral illumination, opacities in the cornea and anterior chamber are not determined, the formations detected in transmitted light are opacities in the lens or in the vitreous. The opacities in the vitreous are mobile, they move even when the eyeball is still. Dull patches in the lens are fixed and move only when the eyeball moves. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction.
Examination in Transmitted Light
The method is used to examine the optically transparent eyeballs (cornea, the anterior chamber, lens, vitreous humor). Given that the cornea and anterior chamber can be inspected in detail with side (focal) illumination, this method is used primarily for the study of the lens and vitreous.
The light source is installed (in a darkened room) behind and to the left of the patient. The doctor with the help of a mirror ophthalmoscope, attached to his right eye, directs a reflected beam of light into the pupil of the patient's eye. For a more detailed study, the pupil should first be expanded with the help of medications. When a light beam hits, the pupil begins to glow red, which is due to the reflection of the rays from the vascular membrane (reflex from the fundus). According to the law of conjugate foci, some of the reflected rays fall into the eye of the doctor through an opening in the ophthalmoscope. In the event that in the path reflected from the fundus of the rays there are fixed or floating opacities, against the background of a uniform red glow of the fundus there appear fixed or moving dark formations of various shapes. If, in the lateral illumination, opacities in the cornea and anterior chamber are not determined, the formations detected in transmitted light are opacities in the lens or in the vitreous. The opacities in the vitreous are mobile, they move even when the eyeball is still. Dull patches in the lens are fixed and move only when the eyeball moves. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction. - it is opacities in the lens or in the vitreous. The opacities in the vitreous are mobile, they move even when the eyeball is still. Dull patches in the lens are fixed and move only when the eyeball moves. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction. - it is opacities in the lens or in the vitreous. The opacities in the vitreous are mobile, they move even when the eyeball is still. Dull patches in the lens are fixed and move only when the eyeball moves. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction. In order to determine the depth of opacification in the lens, the patient is asked to look first up, then down. If the turbidity is in the fore layers, then in the transmitted light it will move in the same direction. If the opacity is in the back layers, then it will shift in the opposite direction.