LogMAR BCVA A. Nystagmus Intensity Measurements Д Д Д Д B. BCVA Measurement Method READING CHART @ 4m FROM PARTICIPANT Nystagmus Intensity (°/s) 20 30 40 50 10 -30 -15 0 15 30 Gaze Angle (°) C. Examples of Intra-subject Correlations Between BCVA and Nystagmus Intensity 0.9 0.8 0.7 0.6 ° 0 0.5 ° ° 0.4 ° 0.3 °° 00 0.2 0.1 0.0 0 20 ° Albinism 0 Grade 1 FH Grade 2 FH • Grade 3 FH • Grade 4 FH Idiopathic IN No FH 40 Nystagmus Intensity (°/s) 60 80 Slope (logMAR/(°/s)) -30° -20° -10° 0° 10° 20° 30° D. Slopes of Intrasubject Correlations between BCVA and Nystagmus Intensity (where r > 0.25) Depending on Degree of Foveal Hypoplasia n 0.03- 10 10 2 3 7 5 ALBINISM 3 0 0 0 IIN 0.02- 0.01- 0.00+ -0.01- -0.02 None Grade 1 Grade 2 Grade 3 Grade 4 Degree of Foveal Hypoplasia
i found this past paper online and am using it for revision but i cannot find the mark scheme anywhere and i dont understand how to do the question but i feel it would be useful revision.
An experiment was carried out to compare intra-subject changes in best-corrected visualvacuity (BCVA) to changing nystagmus in people with albinism and idiopathic infantile nystagmus (a type of nystagmus with mild or no foveal hypoplasia) as shown in Figure 3.
The amount of nystagmus was assessed by calculating nystagmus intensity (peak to peak amplitude x frequency of oscillations) derived from eye movements recorded using a pupil tracker (sample rate: 250 Hz). Participants followed a dot moving from left to right across the horizontal axis in 3° steps from −30° (to the left) to +30° (to the right) (figure 3A). BCVAs were recorded in 10° steps from −30° (to the left) to +30° (to the right) by changing the head posture of the participants. Electronic visual acuity charts were used so that the letters could be randomised (figure 3B).
Figure 3 on the following page shows the intra-subject changes in best-corrected visual acuity (BCVA) to changing nystagmus in people with albinism and idiopathic infantile nystagmus as described in the text above and also in reference to the questions B2.1 and B2.2 below, where:
• n =
• MAR = part of logMAR (measurement of visual acuity which is in logMAR units
where logMAR = Logarithm of the Minimum Angle of Resolution)
• FH = foveal hypoplasia
• IN = infantile nystagmus
• IIN = idiopathic infantile nystagmus
B2.1. The data shown in Figure 3 panel A is for one participant with nystagmus.
i. Describe panel A
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