# PWR-066 — Contrast sensitivity: learner worksheet Release: Revision 7T · Full Tutorial Edition Estimated time: Estimated 27 min reading and worksheet pass Difficulty: Intermediate Equipment: Basic stationery or digital tools — An exact patch recipe for a helper using a slide or drawing program. Make every patch 8 cm square with ten equal stripes and a mean grey of RGB 128/128/128. Alternate stripe greys by level: 1 = 64 and 192; 2 = 96 and 160; 3 = 112 and 144; 4 = 120 and 136; 5 = 124 and 132; 6 = 126 and 130. Rotate the same stripe tile to horizontal H, vertical V or 45-degree diagonal D; export all patches at one pixel size with no labels visible to the learner.; Two folded 18-trial keys. Set A is 1H,1V,1D,2V,2D,2H,3D,3H,3V,4H,4V,4D,5V,5H,5D,6D,6V,6H. Set B is 1D,1H,1V,2H,2V,2D,3V,3D,3H,4D,4H,4V,5H,5D,5V,6V,6H,6D. The helper inserts an unscored level-1 catch patch after trials 4, 8, 12 and 16, with concealed H/V/D order.; A fixed viewing-distance marker and ordinary correction.; Answer key and trial sheet. Space: Desk / seated Automated structural checklist: 10 of 10 structural checks present Evidence quality/context: G2; Deep research depth Automated method-quality band: Comprehensive Method-rating basis: Structure coverage, instruction/check specificity, alternative distinctness, source troubleshooting, comparison depth and whether purpose/check fields are authored rather than derived. Editorial review: Pending manual editorial sign off ## Before you begin - [ ] I read the tutorial authority and stop conditions. - [ ] I have the required equipment/space or a declared accessible alternative. ## Canonical source context Contrast sensitivity can be trained in some clinical settings, but a better test threshold is not generally enhanced vision. This fixture teaches contrast discrimination for one pattern set. The learner begins with obvious stripes, reports orientation before feedback, descends a fixed ladder and retests unfamiliar items. It is not a clinical contrast-sensitivity function and should not be used to clear night driving. The learner also uses catch trials at clearly visible contrast to tell a true low-contrast limit from loss of attention or a habitual orientation response. Target outcome: The learner completes two novel contrast ladders and reports correct orientation by level, false guesses, configuration and symptoms. ### Authority and setup conditions - Set comfortable room light and eliminate screen glare. - Fix display brightness, colour mode, zoom and viewing distance. - Use the ordinary correction for that distance. - Do not use the fixture during migraine aura, acute eye symptoms or a photosensitive episode. ### Required or supplied materials - An exact patch recipe for a helper using a slide or drawing program. Make every patch 8 cm square with ten equal stripes and a mean grey of RGB 128/128/128. Alternate stripe greys by level: 1 = 64 and 192; 2 = 96 and 160; 3 = 112 and 144; 4 = 120 and 136; 5 = 124 and 132; 6 = 126 and 130. Rotate the same stripe tile to horizontal H, vertical V or 45-degree diagonal D; export all patches at one pixel size with no labels visible to the learner. - Two folded 18-trial keys. Set A is 1H,1V,1D,2V,2D,2H,3D,3H,3V,4H,4V,4D,5V,5H,5D,6D,6V,6H. Set B is 1D,1H,1V,2H,2V,2D,3V,3D,3H,4D,4H,4V,5H,5D,5V,6V,6H,6D. The helper inserts an unscored level-1 catch patch after trials 4, 8, 12 and 16, with concealed H/V/D order. - A fixed viewing-distance marker and ordinary correction. - Answer key and trial sheet. ## 1. Fix luminance and geometry Record screen, brightness, room light, patch size and viewing distance. Why: Contrast depends on background luminance and display behaviour. Success check: All configuration fields are filled. Accessible alternative: A spoken or tactile version of “Record screen, brightness, room light, patch size and viewing distance.” can rehearse the response sequence, but it removes the declared visual stimulus and is therefore a related activity, not an equivalent attempt at Contrast sensitivity. To preserve the target, keep the authored visual stimulus and adapt only non-target access such as response input, instructions, breaks or support; retain this success check: “All configuration fields are filled.” Alternative relationship: Related alternative changes trained or measured target Learner notes: ________________________________________________________________________________ Completed: [ ] ## 2. Learn orientations Practise naming the high-contrast horizontal, vertical and diagonal patches. Why: The response labels must be known before contrast falls. Success check: All practice orientations are named correctly. Accessible alternative: Complete “Practise naming the high-contrast horizontal, vertical and diagonal patches.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “All practice orientations are named correctly.” Provide non-glare surrounds and breaks while keeping the tested contrast values unchanged. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 3. Begin above threshold Start with an obvious contrast level and view each patch for the same declared time. Why: Starting easy confirms the task and avoids immediate guessing. Success check: The first two trials are correct without strain. Accessible alternative: Complete “Start with an obvious contrast level and view each patch for the same declared time.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “The first two trials are correct without strain.” Use spoken orientation answers or switches without adding a speed score. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 4. Answer before feedback State orientation and confidence, then reveal the key. Why: A committed response preserves discrimination data. Success check: Every trial has a pre-feedback answer. Accessible alternative: Complete “State orientation and confidence, then reveal the key.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “Every trial has a pre-feedback answer.” Increase the physical patch size only as a declared new accessibility configuration. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 5. Descend the ladder Present the three concealed H/V/D patches at level 1, then levels 2 through 6 in the supplied set order. Give one H, V or D answer per patch and do not skip a level after an error. Why: A fixed adaptive rule and mixed directions reduce pattern guessing. Success check: Each level has exactly one valid H, V and D trial before the next level begins. Accessible alternative: Complete “Present the three concealed H/V/D patches at level 1, then levels 2 through 6 in the supplied set order. Give one H, V or D answer per patch and do not skip a level after an error.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “Each level has exactly one valid H, V and D trial before the next level begins.” Provide non-glare surrounds and breaks while keeping the tested contrast values unchanged. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 6. Stop at repeated uncertainty Stop after level 6 or earlier for glare, headache, visual disturbance or a missed level-1 catch trial that remains wrong after rest; do not raise brightness or repeat faint patches. Why: Changing brightness invalidates contrast and chasing faint items adds strain. Success check: The stop reason is recorded. Accessible alternative: A spoken or tactile version of “Stop after level 6 or earlier for glare, headache, visual disturbance or a missed level-1 catch trial that remains wrong after rest; do not raise brightness or repeat faint patches.” can rehearse the response sequence, but it removes the declared visual stimulus and is therefore a related activity, not an equivalent attempt at Contrast sensitivity. To preserve the target, keep the authored visual stimulus and adapt only non-target access such as response input, instructions, breaks or support; retain this success check: “The stop reason is recorded.” Alternative relationship: Related alternative changes trained or measured target Learner notes: ________________________________________________________________________________ Completed: [ ] ## 7. Retest novel patterns After a delay, use a new orientation order at identical settings. Why: Novel order distinguishes task learning from memorising the sequence. Success check: Settings match and items are unfamiliar. Accessible alternative: Complete “After a delay, use a new orientation order at identical settings.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “Settings match and items are unfamiliar.” Increase the physical patch size only as a declared new accessibility configuration. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 8. Insert visible catch trials After every four difficult patches, present one clearly visible patch in a concealed orientation. If that catch trial is wrong, pause and mark the preceding difficult group as attention-affected rather than lowering contrast again. Why: A high-contrast catch trial should remain easy. Missing it suggests fatigue, response-key confusion or a lapse rather than a new contrast threshold. Success check: Catch-trial orientation is correct, or the affected group is labelled and the learner rests before continuing. Accessible alternative: A supported, seated, reduced-range or slower version of “After every four difficult patches, present one clearly visible patch in a concealed orientation. If that catch trial is wrong, pause and mark the preceding difficult group as attention-affected rather than lowering contrast again.” is equivalent only when it keeps the same trained or measured target, declared configuration and success check: “Catch-trial orientation is correct, or the affected group is labelled and the learner rests before continuing.” If any of those change, record it as a related alternative rather than an equivalent repetition. Alternative relationship: Conditional equivalence requires target and configuration check Learner notes: ________________________________________________________________________________ Completed: [ ] ## Reflection What changed? ________________________________________________________________________________ What remains difficult? ________________________________________________________________________________ What will I repeat, adapt, ask for help with, or stop? ________________________________________________________________________________ --- Completion of this worksheet demonstrates tutorial participation only. It does not establish capability, qualification, safety clearance, diagnosis, treatment or independent validation.