Skiascopy: what it is, the methodology, interpretation of results
In modern conditions the number of patients with pathology of the organ of vision is growing exponentially. Already from an early age many children are registered at the ophthalmologist about a particular disease. Examination and admission Committee of higher and secondary educational institutions to identify healthy in this respect, individuals with extremely low frequency. Despite the fact that science does not stand still, and there are many modern methods of diagnosis, not being deprecated, this method of research, as skiascopy.
Definition and relevance of the methodology
Skiascopy was proposed half a century ago by a French doctor. Such a study is conducted to refractive ability of the eye to determine the presence of ocular pathology.
The range of diseases that can be detected when the shadow study is small. But this is the most common and important disease, which should start to correct as early as possible:
- Myopia (nearsightedness) of varying degrees of severity.
- Numerous varieties of astigmatism (violation of sphericity of the cornea and/or lens).
If you suspect the list of pathological conditions of the organ of vision should be performed the study. What situations more and more often require these techniques?
- Children’s age after 7 years.
- Mental illness with pronounced psychotic component.
- Mental retardation and other conditions in which the level of cognitive disability restricts possibilities for other types of studies of the organ of vision.
- The suspicion of simulation and aggravation.
- Conduct professional examinations and other types of examination, because of low cost.
- But the method has several disadvantages, which explains the existing contraindications.
When conducting skiaskopia not shown?
Children before reaching the age of seven do not pass the shadow study. In addition, skiascopy is contraindicated in various States, accompanied by severe photophobia (photophobia).
Especially dangerous is the conduct of studies in children in the presence of photophobia.
Another disease in which ophthalmologists have not conducted the study, is glaucoma. Skiascopic examination will aggravate the situation, leading to increased intraocular pressure.
The methodology of the
Retinoscope (another name of the method) is carried out by an eye doctor (ophthalmologist) in a specialized office, where you can create the necessary lighting. What should be in the Arsenal of eye doctor to conduct skiaskopia?
- Electric lamp (a special lamp).
- Mirror or skiascopy.
- Lenses or skiaskopia line.
Before having the procedure, should be drip for upper eyelid the drug which causes mydriasis – persistent mydriasis. This allows you to adequately and without distortion to determine the presence of pathology and its degree of severity. Usually use Atropine or Eririn.
Then the studied sits near the doctor. The distance between them is 1 meter. This is important for calculations and selection of optical. On the left side of the patient is the source of light –the electric lamp. The doctor directs with the help of a special mirror and the hole in it the concentrated beam. It needs to be in the area of the fundus. Then is the norm. The pupil will be red. In order to avoid zagareanu, the patient is asked to look at the earlobe of the doctor.
Then, the doctor moves the mirror first in horizontal and then in vertical direction. This is necessary for accurate determination of violations of the refractive ability of the visual organ. The next stage, the selection of lenses.
The decoding result is carried out on site in terms of ophthalmic office. The doctor evaluates how well does the shadow in the pupillary area of the hole when moving flat mirrors.
Often there is the following situation. A shadow moved in the similar direction skiascope. That is, if the mirror moves up, and the shadow in the pupil moved in this direction. About what it can speak?
- Hyperopic type of refractive error, typical for elderly patients with a tendency to longsightedness.
- Emmetropia (absolutely normal refractive ability of the eye).
- Myopic disease of a low degree (less than 1.0 diopter).
There is the opposite situation. A shadow in the pupil moves in the opposite relative to the moving mirror direction. Here, obviously, there is a myopia more severe.
Finally, a special case occurs when the shadow reaction is mixed. Then there is a astigmatism. To clarify the type of astigmatic refractive error should be bar-skiascopy.
The technique of neutralization of shadow phenomenon necessary for corrective optics. It is possible for this purpose to apply the lenses for conventional glasses selection or a whole line of skiaskopia glasses. Keep them on distance from eye approximately 1.2 cm Try on different lenses to eventually achieve the disappearance of the shadow. Then the power of the lens should subtract unit, and will be calculated the degree of myopia. Farsightedness unit add to the value of the lens, which shadow reflex disappeared. So establish the degree of refractive error and pick up the optics for the correction.