Bagolini Striated Glasses Test

Bagolini striated glasses test, or BSGT, is a subjective clinical test to detect the presence or extent of binocular functions and is generally performed by an orthoptist. It is mainly used in strabismus clinics. Through this test, suppression, microtropia, diplopia and manifest deviations can be noted. However this test should always be used in conjunction with other clinical tests, such as Worth 4 dot test, Cover test, Prism cover test and Maddox rod to come to a diagnosis.

To perform the test you will need

Alternatively, trial frames and lenses or a lorgnette can be used. In some cases, the use of prisms is necessary to measure a deviation and test for the presence of binocular functions.

Bagolini striated glasses are glasses of no dioptric power that have many narrow striations running parallel in one meridian. These glasses cause the fixation light to appear as an elongated streak perpendicular to the striations. The lenses are usually placed at 135 degrees in front of the one eye and at 45 degrees in front of the other. Each eye receives a similar, fusible image, with the exception of the line, allowing simultaneous perception to be observed. With both eyes, the patient should see a cross. This test is minimally dissociative for the assessment of retinal correspondence.

Apart from testing binocular functions, Bagolini striated glasses can measure cyclotropia . The principle of the test is similar to that of double Maddox rod test. The glasses are placed in the trial frames with the striations vertical, giving rise to two horizontal line images when viewing a spotlight. If the patient has a vertical deviation, the lines will be seen one above the other. If there is little or no vertical separation, vertical prism can be used to separate the lines. The patient is asked if one or both lines are tilted. The lines can be straightened subjectively by rotating the glasses in the trial frame and the degree of cyclotropia recorded.

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