Modifications Made to the Refractive Result when Prescribing Spectacles
Bibliographic record
Abstract
PURPOSE: The purpose of this study was to determine how optometric practitioners modify the subjective refractive result when prescribing spectacles. METHODS: Refractive data were gathered for patient visits at the School of Optometry, University of Waterloo, between January 2007 and January 2008. The entering prescription, subjective refraction, and exiting prescription were analyzed from 5001 records for patients aged ≥ 7 years. RESULTS: The refraction was modified to create the prescription in at least one eye in 45% of cases; specifically, 27% of cases for the sphere power, 18% for the cylinder power, 25% for the cylinder axis, and 21% for the add. Significant differences, defined as ≥ 0.50 D in sphere, cylinder, or add power or a change in axis of 15° for cylinders < 1 D, 10° for cylinders between 1 and ≤ 2, and 5° for cylinders >2, were made in at least one eye in 17% of cases; specifically 9% of cases for the sphere power, 6% for the cylinder power, 6% for the cylinder axis, and 5% for the add. Spheres were more likely to be modified in the minus direction (weaker plus and stronger minus power) (18 vs. 11%), cylinder powers reduced (14 vs. 5%), and adds increased in power (12 vs. 8%). Modifications to create the exiting prescription were made to be closer or the same as the entering prescription 97% of the time. However, modifications were such that the entering prescription was duplicated exactly only 0.7% of the time. CONCLUSIONS: Optometric practitioners routinely modify the subjective refraction to create the prescription. Small modifications are common, whereas larger modifications are used more sparingly. Because there is a significant amount of clinical judgment involved in determining the refractive prescription, reliance on automated or subjective refraction alone would not be prudent.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".