Effect of Time on Scleral Lens Settling and Change in Corneal Clearance
Bibliographic record
Abstract
SIGNIFICANCE: With the increase in the use of scleral contact lenses among practitioners, questions regarding lens settling are gradually gaining attention. This is because current studies support the notion that scleral lenses settle back over time. More research is needed to understand the exact cause and the factors that underpin such phenomenon. PURPOSE: The present study aims to assess the effect of time on topographic corneal clearance of three scleral contact lenses of varying sagittal depths. METHODS: Three scleral contact lenses were fitted to 20 subjects with previous diagnosis of keratoconus (n = 18) or pellucid marginal degeneration (n = 2). The fit was based on corneal sagittal height measured with the Visante optical coherence tomographer (OCT) at 15 mm along the horizontal meridian. To select an appropriate lens from the diagnostic lens set, values of 325 μm (lens 1), 375 μm (lens 2), and 425 μm (lens 3) were randomly added in sequence to the corneal sagittal height. Subjects wore each lens for 1 hour. Corneal clearance was measured at 10-minute intervals for 1 hour using a custom ultra-long OCT. To assess change in clearance, central point and two mid-peripheral points (+3 mm and -3 mm) along an 8-mm chord were measured by taking differences at each time point up to 1 hour. Measurements were repeated for the two other lenses. RESULTS: Mean central corneal clearance loss for all three lenses was 33.83 ± 48.40 μm. This was 26 ± 27 μm (13 ± 14 μm, +3 mm; 34 ± 37 μm, -3 mm), lens 1; 35 ± 59 μm (38 ± 61 μm, +3 mm; 52 ± 69 μm, -3 mm), lens 2; and 41 ± 54 μm (33 ± 26 μm, +3 mm; 52 ± 48 μm, -3 mm), lens 3, respectively. There was no significant difference (P = 0.06) at central and other locations for lens 1 (location and over time). There were significant differences for both lenses 2 and 3 (P < .001, P = .01, respectively) for all three locations and over time. CONCLUSIONS: There is a likelihood of clearance loss after 1 hour of lens wear. This varies between subjects, initial lens-fit relationship, and over time.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.004 | 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".