Oxygen tension beneath piggyback contact lenses and clinical outcomes of users.
Bibliographic record
Abstract
PURPOSE: Patients with keratoconus sometimes wear a rigid contact lens as a piggyback over a countersunk soft one. This geometry restricts movement of the rigid lens over the central cornea and may also reduce corneal oxygenation. This aim of this study was to estimate the equivalent oxygen percentage beneath such lenses and to review the clinical records of users to determine their success rate. METHODS: The right eyes of four normal subjects were covered for 5 minutes with a combination of rigid gas permeable (Boston ES or 7 [Polymer Technology Corp., Rochester, NY]) and soft (Acuvue [Johnson & Johnson, Jacksonville, FL], Keraflex [KF] 3 or 5 [Blanchard, Sherbrooke, QC, Canada]) contact lenses. After removal of the lenses, oxygen tension was measured with a Clark electrode. In order to determine whether measurements of oxygen tension were supported by clinical data, the clinical files of 11 patients fitted with KF 5-Boston ES piggyback lenses were reviewed for the presence of corneal edema. RESULTS: Mean relative equivalent oxygen percentage ranged from 6.9% to 11.2% beneath the following lens combinations: KF 3-Boston ES; KF 3-Boston 7; KF 5-Boston ES; KF 5-Boston 7; Acuvue-Boston ES; and Acuvue-Boston 7. Of the ten patients followed after dispensing, none had any sign of corneal edema. Nine had worn their contact lenses for periods up to 6 years. CONCLUSIONS: Based on the measured equivalent oxygen percentage and on the absence of corneal edema in patients, the combination of countersunk KF 5 with Boston ES lenses provides enough oxygen to fulfill corneal needs in oxygen during daily wear.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".