Table 7.
Clinical signs found at the vision examination in all included patients
| Clinical Sign | Patients, n (%) | Comment |
|---|---|---|
| Refractive error (n=42) | ||
| Suboptimal refractive correction | 12 (28.6) | |
| Contrast sensitivity (n=26) | ||
| Sensitivity below expected according to age | 4 (15.4) | Cataracts (n=2) |
| Eye motility and versional (gaze) eye movements (n=42) | ||
| Eye motility restriction | 1 (2.4) | Premorbid condition |
| Fixation (saccadic intrusions, detectable drifts, or nystagmus) | 2 (4.8) | |
| Smooth pursuit (intruding saccades or head movements) | 4 (9.5) | |
| Visually induced saccades (long latency, dysmetria, head movements) | 3 (7.1) | |
| Voluntary saccade (variable or prolonged latency, dysmetria, head movements, stops due to discomfort) | 12 (28.6) | |
| Head movement and motion sensitivity | ||
| VOR head movement (patient-reported discomfort or observed fixation loss) (n=39) | 12 (30.8) | |
| Hand motion in peripheral visual field (patient-reported discomfort, observed fixation loss) (n=41) | 6 (14.6) | |
| Binocular (eye teaming) functions (patients with stereovision, n=39) | ||
| Reduced fusion vergences at distance (3 m) | 20 (51.3) | |
| Reduced fusion vergences at near (40 cm) | 15 (38.5) | |
| Reduced near point of convergence | 9 (23.1) | |
| Reduced convergence facility | 26 (66.7) | |
| Accommodative function (age <40 y, n=6) | ||
| Reduced accommodative amplitude | 3 (50.0) |
NOTE. Clinical signs are deviations in visual function, ie, where the criteria for normal function are not met. The criteria are listed in table 3. Eye motility concerns the ability to move the eyes in all directions without restriction or experiencing double vision. Versional, or gaze, eye movements are when the eyes move in unison in the same direction. The movements are stabilizing (fixation), rapid (saccades), or following (pursuit) and are essential for the acquisition of visual information, eg, through focusing, visual search and/or scanning of the environment and tracking of moving objects. Binocular functions concern the teaming of the eyes. Eye teaming is essential for maintaining clear and single (not double) vision and to adjust for different viewing distances. Eye teaming happens through vergence eye movements where the eyes move in opposite directions.