Manual for the application of prism strabismus compensators.
A set of prismatic strabismus compensators is designed to measure the squint angle or squint angle compensation for orthopto-diploptic treatment in the ophthalmologic clinics, eyesight test cabinets and in the ophthalmologic departments of hospitals specialized in the treatment of strabismus.
Method of application
The doctor is located opposite the patient at a distance from 0.67 m to 1 m.
A patient is put on a test universal eye-glass rim with a precisely set interpupillary distance. If necessary, you could install lenses in the test the eye-glass rim to correct ametropia. The patient should fix a point source of light or another fixation object located at a distance of 30 cm from the patient (when measuring the squint angle for close distance). At measuring the angle of strabismus for the distance, the patient records the optotypes of the table for checking visual acuity corresponding to his visual acuity from a distance of 5 m.
An alternating cover test is conducted to detect the presence and direction of the installation movements of the eyes, alternately covering the left and right eyes with an occluder. Then, a minimum size prism is installed in the lens holder of the test frame in front of the better seeing or more often fixing eye so that the triangular index of the prism compensator marking, indicating the direction of action of the prism, is directed toward the deflection of the eye.
Occludor 3-4 times alternately for 2-3 seconds closed the right and left eye, paying attention to the presence or absence of the installation movements. If such movements are observed, the force of the prism increases or decreases until the installation movements are completely neutralized, which means that the deviation angle is neutralized. If a prism with a force of 30 PD in front of one eye does not eliminate the installation movements, prisms of increasing force have to be placed in front of the other eye (maximum 30 PD), achieving complete neutralization of the installation movements. If the setting movements are not eliminated, further measurements of the squint angle are impossible (angle greater than 60 prism diopters).
The sum of the force of the prisms attached to both eyes, with which there are no adjusting movements, corresponds to the magnitude of the angle of deviation.
Angle measurement with converging and diverging strabismus (esotropy, exotropia)
You have to install prism compensators in increasing order at the lens holder of the test spectacle rim in front of a better seeing or fixing eye, the direction of action of which corresponds to the direction of eye deflection (marking with a triangular index indicates this direction: in esotropy it must be directed to the nose, in exotropia it must be directed to the temple). To identify mounting movements, perform a cover test. In the presence of horizontal mounting movements, increase the force of prism compensators until they completely disappear. The strength of the prism, at such there are no adjusting movements, determines the angle of strabismus.
Angle measurement with vertical strabismus (hypertropy, hypotropy)
Install prisms in increasing order at the lens holder of the test spectacle rim in front of the better seeing or fixing eye, the direction of action corresponds to the deviation of the eye (in hypertrophy, the direction of the marking index is up, in case of hypotropia, downward) until the vertical mounting movements disappear. The quantitative value of the force of prisms, necessary for the elimination of adjusting movements, is equal to the angle of strabismus.
Angle measurement with combined strabismus (horizontal with vertical component)
Install prisms in increasing order at the lens holder of the test spectacle rim in front of the better seeing or fixing eye to compensate for the horizontal deviation of the eye (during esotropy direction of the marking index of the prism compensator must be directed to the nose, at exotropia it must be directed to the nose to the temple) until the horizontal installation movements disappear.
Then, without removing the prisms that compensate horizontal deviation, additionally install in vertical order prisms of vertical action (in hypertrophy, the direction of the marking index is up, in case of hypotropia, downward) until the vertical adjusting movements disappear to compensate for the vertical component of the deviation.
The magnitude of the strabismus angle consists of a horizontal deviation equal to the quantitative value of the prisms used to eliminate the horizontal mounting movements and the vertical deviation corresponding to the strength of the prisms necessary to compensate for the vertical mounting movements.
All microprism devices have passed the necessary medical tests and patented in Ukraine.
1. Patent 18152 Ukraine. Device for measuring angle of heterotropy / Sergієnko MM, Petrov V.V., Rikov S.O., Shanojlo S.M., Shevkolenko M.V., Kryuchin A.A .; Owner of Kyiv City Clinical Ophthalmological Hospital "Center of Eye Microsurgery" - No. 2006 07554; application 07.07.06; Published on October 16, 2006 by Bul. No. 10
2. Patent 25549 Ukraine. A device for strabismus diagnosis / Petrov VV, Sergienko MM, Rykov SO, Shanoyolo SM, Shevkolenko MV, Kriyan AA, Antonov Ye.E. the owner of the Institute of Information Recording Problems of the National Academy of Sciences of Ukraine - No. 2007 04035; Declared.12.04.07; published 08.10.07, Bul. No. 12
3. Patent for utility model 46750 Ukraine. Microprise lens of combined action / Petrov VV, Kryabin AA, Rykov SO, Sergienko MM, Antonov E. E., Mellina VB, Shanyalo S. M., Shevkolenko M. IN.; the owner of the Institute of Information Recording Problems of the National Academy of Sciences of Ukraine - № u 2009 04525; application 07.05.09; published 11.01.10, Bul. No. 1
4. Patent for utility model 76872 Ukraine. Diagnostic set of symmetric microprism strabismus compensators. / Petrov VV, Kryabin AA, Rykov SO, Sergienko MM, Antonov E.Ye., Shanoyolo SM, Shevkolenko MV; the owner of the Institute of Information Recording Problems of the National Academy of Sciences of Ukraine - № u 2012 05126; declared 25.04.12; Published on January 25, 13, BUL. No. 2