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The diagnostic procedure used by ophthalmologists to obtain accurate and reliable data on the parameters of the organ of vision is called ultrasound biometry. This study is considered more accurate than classical ultrasound diagnostics, therefore it is mandatory before laser vision correction.
Features and types of eye biometrics
With the help of eye biometrics, you can measure its length and depth of the anterior chamber, find out the parameters of the lens and the thickness of the cornea. The examination is performed by optical and ultrasonic devices. The results of the procedure are needed for the doctor to make an accurate diagnosis, monitor the condition of the cornea. With the help of biometrics, the specialist can choose the most suitable contact lenses for the patient. Also, during the manipulation, the doctor can diagnose glaucoma (increased intraocular pressure).
Eye biometrics allows you to identify a person, since the iris of the eye is unique for each person. The procedure is applied quite often, is accurate and fast. Abroad, with the help of manipulation, the received data is recorded in a single database, which allows them to be further viewed and analyzed. Also, in some countries, eye biometrics is done for issuing a biometric passport.
There are 2 types of biometrics: ultrasonic and optical. Ophthalmologists most often use the first type. With its help, the parameters of the organ of vision are recorded, and then analyzed by a specialist. As a result of the diagnosis, it is possible to calculate the optical power of the intraocular lens, objectively assess the progress of myopia, monitor the effectiveness of therapy aimed at stabilizing myopia (myopia).
Optical examination by physicians is considered more modern and progressive. It belongs to non-contact diagnostic methods in ophthalmology. As a result of optical biometry of the eye, it is possible to measure the posterior and anterior axis of the organ of vision, the depth of the anterior chamber, and conduct keratometry (assessment of the curvature of the surface of the cornea).
The optical procedure helps to choose intraocular lenses for the patient, while taking into account the individual parameters of the organ. The main condition for successful manipulation is the transparency of optical media.
Indications and contraindications for the procedure
Ultrasonic biometrics of the organ is prescribed by an ophthalmologist after examining the patient and obtaining the results of the tests. Manipulation is carried out in order to diagnose diseases and establish the dynamics of disease progression. It is also necessary to conduct studies to test the treatment of myopia and other diseases of the organ.
Other indications for the procedure include: glaucoma, cataracts (complete or partial clouding of the lens), suspicion of benign and malignant neoplasms, pathological changes in the organ of vision, mechanical trauma to the eye, decreased transparency of optical media, mild inflammatory processes in the eyes.
Contraindications include:
- severe inflammation of the organ;
- purulent diseases of the studied area;
- lens diseases.
If the patient feels unwell before the study, he must inform the attending physician about this. The doctor will take all necessary measures to protect the patient from the appearance of adverse reactions and complications.
Generally accepted norms during the study
The normal result of diagnosis for adult men and women is the length of the eye axis of about 22-24 millimeters. Children under 4 years of age should have an eye axis length of 20 to 22 millimeters. From 4 to 18 years old in humans, this parameter should vary from 22 to 24 millimeters.
If, as a result of the procedure, a woman or a man has an eye axis length of 18 to 22 millimeters, this indicates hyperopia, with 24 millimeters or more – myopia. The normal values of an ultrasound examination of the eyes of people differ and are individual, therefore only a qualified doctor can make an accurate diagnosis.
Carrying out ultrasound biometrics of the eye
The procedure is performed by a special device called a biometer. There is no need to prepare for the manipulation, it is absolutely painless and the patient does not feel any discomfort. The duration of the study varies from 15 to 30 minutes.
The patient should lie on his back on the couch. A thick layer of water-soluble gel is applied to the skin near the eyelids, which is used for almost all ultrasound examinations. The gel improves the conductivity of ultrasonic radiation and will prevent the penetration of oxygen between the epidermis and the transducer.
The ophthalmologist or ultrasound specialist fixes the transducer with his hand on the eye that is to be examined. The patient must be immobile during the diagnosis, because any body movements will make it difficult for the ultrasound waves to penetrate. The doctor may ask the patient to hold their breath for 3-5 seconds during the procedure in order to make the image clearer.
The waves are reflected and converted into electrical impulses. These impulses are processed by the scanner and turn them into a digital image. During the procedure, the person does not feel pain. The only disadvantage of manipulation is that the patient should be motionless. Sometimes medical staff will hold the person’s head during the examination.
At the end of the diagnosis, the specialist wipes the gel from the eyelids with a napkin or cotton swab. Then the specialist goes to decipher the results of ultrasound biometrics (decoding takes from 10 to 15 minutes).
The main advantage of manipulation is the availability of portable devices for conducting ultrasound examinations. Therefore, it is possible to examine a person, if he is paralyzed or has problems with the musculoskeletal function, even at his home. Other advantages of the procedure are: affordable cost, safety and painlessness of eye biometrics. Also, this manipulation is carried out for women during pregnancy and during lactation due to safety and minimal radiation.
It is very important to diagnose on time, when the symptoms have just begun to appear. This will prevent the appearance of unpleasant processes, diseases and even save your eyesight. Ultrasound biometrics is an effective technique that allows you to examine the state of the organ of vision and other areas of the human visual apparatus.