Bagolini striated glasses can be used to assess sensory function in strabismus. They can help determine presence of diplopia, suppression, the presence of anomalous retinal correspondence, as well as the presence of the monofixation syndrome What is special about these lenses? Like Maddox rod they also convert a point source of light into a straight line They are less dissociating than a Maddox rod, in fact they are the least dissociating of all the sensory tests They permit near normal viewing and fusion and, Cover testing can be performed simultaneously while wearing the lenses. This is a binocular test. After performing a cover test to determine the presence of a tropia, the lenses are placed in front of the eyes such that the striations are placed from the patient’s point of view at 135 degrees in front of the right eye & 45 degrees in front of the left eye, (that is , striations oriented upward & inward) & the patient is asked to fixate on a distant light. Since the streak of light is seen perpendicular to the striations, the patient will see a line in this direction from the right eye, & this direction from the left eye. So in a normal person, the binocular fusion response looks like this; since the patient has near normal vision through Bagolini lenses, the central fixation light is also seen. Let’s see some examples Scenario 1 → The patient sees this, (this is essentially what a normal person sees), but cover testing reveals the presence of a tropia. Since both lines are seen there is no suppression, the light is single so no diplopia, the lines cross in the center so there is binocular fusion, so this is a case of an ocular deviation with anomalous retinal correspondence, SO this pattern with no deviation indicates normal retinal correspondence, & in the presence of a deviation indicates ARC. Scenario 2 → This is what the patient sees. A single light so no diplopia; in fact only the line from the left eye is seen. Cover test shows the presence of a tropia. So this is a case of a right tropia with suppression Scenario 3 → This is what the patient sees? How do we interpret this? Since only a single light is seen, there is no diplopia. Since lines from both eyes are seen, there is no gross suppression. Both lines cross each other exactly in the middle which means there is fusion, the line from the right eye has a small central gap — this is a foveal suppression scotoma, & this is classic of monofixation syndrome. In monofixation syndrome, there is a foveal suppression scotoma in one eye, with peripheral fusion. Cover testing will reveal either no deviation or a tropia of ≤ 10 pd Scenario 4 → This is what the patient sees? Here two lights are seen so there is diplopia; this of course means that there is a deviation & there is no suppression. Next let’s see the type of diplopia — the light seen on the right belongs to the right eye, so the diplopia is uncrossed, so the patient has an esotropia, which is what the cover test would show. So this is a right esotropia with normal retinal correspondence & absence of suppression Scenario 5 → This is what the patient sees? Here again there are two lights so diplopia is present ; again this means there is a deviation & no suppression. Here the light seen on the right belongs to the left eye, so the diplopia is crossed, so the cover test will show an exotropia. So this is a right exotropia with normal retinal correspondence & absence of suppression Sometimes, depending on the deviation, there may be a greater horizontal separation of images, or if there is a vertical component, the images may be vertically separated as well