# PWR-065 — Visual acuity: learner worksheet Release: Revision 7T · Full Tutorial Edition Estimated time: Estimated 25 min reading and worksheet pass Difficulty: Intermediate Equipment: Common household or practice equipment — An exact two-ladder construction sheet. A helper makes six rows per ladder at 72, 60, 48, 36, 30 and 24 px in DejaVu Sans or the same available sans-serif font. Each row has four separated groups of five identical arrows except one arrow pointing in the opposite direction; group base directions cycle up, right, down and left. Odd-arrow positions for ladder A, largest to smallest, are [3,5,2,4], [1,4,5,2], [2,5,3,1], [4,1,5,3], [5,2,4,1], [3,1,2,5]. Ladder B uses [2,4,1,5], [5,3,2,1], [4,2,1,3], [1,5,3,2], [2,3,5,4], [4,5,1,2]. The helper folds this position key and labels rows only by size.; One screen or printed card kept at a marked distance and size.; Ordinary prescribed glasses or contact lenses.; A ruler/tape and record for lighting, correction, row accuracy and symptoms. 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 Visual acuity can improve in selected amblyopia treatment settings, but this is not a route to superhuman eyesight. The low-risk teachable version is a symbol-discrimination fixture, not home measurement of visual acuity. The learner fixes screen, distance, lighting and usual correction, answers once per row, records errors and repeats with a novel ladder. Clinical visual acuity requires standardised charts and qualified interpretation. Target outcome: The learner completes the supplied A and B symbol ladders with fixed configuration and reports four-group accuracy and confidence at each displayed size. ### Authority and setup conditions - Use the same eye correction normally used for the selected viewing distance. - Choose even comfortable lighting without glare and mark the viewing position. - Do not cover or patch an eye if a clinician has told you not to; record whether one or both eyes are used. - New or sudden visual loss, eye pain, flashes, a curtain-like shadow or double vision needs prompt eye care, not practice. ### Required or supplied materials - An exact two-ladder construction sheet. A helper makes six rows per ladder at 72, 60, 48, 36, 30 and 24 px in DejaVu Sans or the same available sans-serif font. Each row has four separated groups of five identical arrows except one arrow pointing in the opposite direction; group base directions cycle up, right, down and left. Odd-arrow positions for ladder A, largest to smallest, are [3,5,2,4], [1,4,5,2], [2,5,3,1], [4,1,5,3], [5,2,4,1], [3,1,2,5]. Ladder B uses [2,4,1,5], [5,3,2,1], [4,2,1,3], [1,5,3,2], [2,3,5,4], [4,5,1,2]. The helper folds this position key and labels rows only by size. - One screen or printed card kept at a marked distance and size. - Ordinary prescribed glasses or contact lenses. - A ruler/tape and record for lighting, correction, row accuracy and symptoms. ## 1. Lock the configuration Record display, zoom, card size, distance, lighting, correction and whether one or both eyes are used. Why: Symbol size changes with every one of these choices. Success check: A second person could reproduce the setup. Accessible alternative: A spoken or tactile version of “Record display, zoom, card size, distance, lighting, correction and whether one or both eyes are used.” can rehearse the response sequence, but it removes the declared visual stimulus and is therefore a related activity, not an equivalent attempt at Visual acuity. 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: “A second person could reproduce the setup.” Alternative relationship: Related alternative changes trained or measured target Learner notes: ________________________________________________________________________________ Completed: [ ] ## 2. Learn the response rule For each of the four groups on a row, say the odd arrow's position from 1 to 5 before the helper reveals the folded key. Do not revise a blurred answer after feedback. Why: One fixed question keeps the score about detail discrimination. Success check: The learner gives four position answers on each of two large practice rows and can explain how positions are counted. Accessible alternative: A supported, seated, reduced-range or slower version of “For each of the four groups on a row, say the odd arrow's position from 1 to 5 before the helper reveals the folded key. Do not revise a blurred answer after feedback.” is equivalent only when it keeps the same trained or measured target, declared configuration and success check: “The learner gives four position answers on each of two large practice rows and can explain how positions are counted.” 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: [ ] ## 3. Start with obvious rows Begin at 72 px and give all four group positions before checking or moving to the next size. Why: Easy rows establish the task without forcing strain. Success check: Each row has four recorded positions and one confidence rating before feedback. Accessible alternative: A supported, seated, reduced-range or slower version of “Begin at 72 px and give all four group positions before checking or moving to the next size.” is equivalent only when it keeps the same trained or measured target, declared configuration and success check: “Each row has four recorded positions and one confidence rating before feedback.” 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: [ ] ## 4. Descend one row at a time Continue toward smaller rows while keeping head and card at the mark and using the same allowed viewing time. Why: Leaning or zooming makes a smaller symbol larger. Success check: Distance and zoom remain unchanged. Accessible alternative: Complete “Continue toward smaller rows while keeping head and card at the mark and using the same allowed viewing time.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “Distance and zoom remain unchanged.” Use a chin/forehead distance marker only if comfortable and non-restrictive. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 5. Use a stopping rule Stop at the 24 px row or earlier for blur that persists after ordinary blinking, headache, eye pain, nausea or other visual discomfort; never repeat a row to improve its count. Why: The fixture reports performance by size and does not need a clinical-style threshold chase. Success check: The end reason is 24 px or a named symptom, and no row is replayed. Accessible alternative: A spoken or tactile version of “Stop at the 24 px row or earlier for blur that persists after ordinary blinking, headache, eye pain, nausea or other visual discomfort; never repeat a row to improve its count.” can rehearse the response sequence, but it removes the declared visual stimulus and is therefore a related activity, not an equivalent attempt at Visual acuity. 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 end reason is 24 px or a named symptom, and no row is replayed.” Alternative relationship: Related alternative changes trained or measured target Learner notes: ________________________________________________________________________________ Completed: [ ] ## 6. Score from the key Compare the four positions with the folded key, record 0–4 correct for each size and retain every wrong position; do not convert a home row to Snellen or logMAR. Why: The fixture lacks clinical calibration. Success check: Raw row accuracy and confidence remain visible. Accessible alternative: Complete the same research action — “Compare the four positions with the folded key, record 0–4 correct for each size and retain every wrong position; do not convert a home row to Snellen or logMAR.” — using speech-to-text, text-to-speech, enlarged text, keyboard-only navigation, shorter work blocks or a support person. Preserve this declared check: “Raw row accuracy and confidence remain visible.” Do not convert the research task into capability practice. Alternative relationship: Target preserving when declared check is preserved Learner notes: ________________________________________________________________________________ Completed: [ ] ## 7. Retest with a new ladder After at least 48 hours, use the second ladder in the identical setup. Why: A new item reduces memorisation of the symbol sequence. Success check: Configuration matches and item order is unfamiliar. Accessible alternative: Complete “After at least 48 hours, use the second ladder in the identical setup.” in shorter passes, or use keyboard input, dictation or a support person, while preserving this success check: “Configuration matches and item order is unfamiliar.” Use a chin/forehead distance marker only if comfortable and non-restrictive. Alternative relationship: Target preserving when declared check is preserved 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.