Purpose:
Schober test assesses the client´s binocular coordination. The test measures the relative horizontal and vertical deviation of the eyes, one with respect to the other, when fusion is broken (dissociated with two tinted lenses being put in a trial frame). The traditional test is performed on a paper form. The client usually reports where the middle cross is in relation to the circle. With an application, the client simply moves a cross around the screen and the programme interprets the result.
Equipment and set-up:
Put a red glass filter in front of the clpatient´s right eye and the green filter in front of the left eye over his the correction for the distance. The test is held at 40 cm. Show the patient client this test and ask him them about the position of the red cross in relation to the green circles. If the cross is not spot on in the centre, ask a patthe client to touch the cross and to slide it into the centre of two green circles. If there is a phoria, the cross moves corresponding according to the angle of phoria. The programme will show you the direction and the value of heterophoria. It will interpret the result and show how many prisms the clpatient needs in which direction (IN, OUT, UP, DOWN).
Interpreting the results:
- EXOPHORIA (the cross is moved into the left, or the circles are moved into the right) -> Correction: PRISM BASE NASAL
- ESOPHORIA (the cross is moved into the right, or the circles are moved into the right) -> Correction: PRISM BASE TEMPORAL
- RIGHT HYPOPHORIA or LEFT HYPERPHORIA (the cross is moved upwards, or the circles are moved downwards) -> Correction: PRISM BASE UP
- RIGHT HYPERPHORIA or LEFT HYPOPHORIA (the cross is moved downwards, or the circles are moved upwards) -> Correction: PRISM BASE DOWN
Combinations:
- EXOPHORIA AND RIGHT HYPOPHORIA (the cross is moved into the left and upwards, or the circles are moved into the right and downwards)
- EXOPHORIA AND RIGHT HYPERPHORIA (the cross is moved into the left and downwards, or the circles are moved into the left and upwards)
- ESOPHORIA AND RIGHT HYPOPHORIA (the cross is moved into the left and upwards, or the circles are moved into right and downwards)
- ESOPHORIA AND RIGHT HYPERPHORIA (the cross is moved into the right and downwards, or the circles are moved into the left and upwards)
Special cases:
Schober test may also help in the diagnostic assessment in paediatrics with anisometropic (unequal refractive power of the two eyes) amblyopia. If a child sees the rings when the green lens is in front of the amblyopic eye but not the cross when the red lens is in front of the amblyopic eye, the area of suppression of the image of that eye is very small, the size of the cross. If suppression of the amblyopic eye is weak, a child might report that the cross may be seen “blinking”, which means the cross appears for a short time and then disappears again for a short time. In such case suppression is weak and can be usually broken in a short time. If the child has intensively trained the amblyopic eye, visual acuity may become normal within a month.
