Tear Film and Lid Margins in Over-Blink
Bibliographic record
Abstract
Purpose It is generally accepted that the eyelid margins touch each other in spontaneous blinks while spreading the lipid over the tear film in the upwards movement of the upper lid. In contrast, recent research has demonstrated that the central upper lid (UL) and lower lid (LL) do not touch in spontaneous blinks due to an over-blink (OB). Furthermore a lissamine green drop, placed onto the anterior portion of the central LL, was demonstrated to be unchanged in spontaneous blinks (drop-test). The aim of this project was to evaluate UL and LL margins movements and a possible tear film spreading model based on the new knowledge. Methods In 15 subjects (9 female; median age= 45) lid-margin thickness of the opened eye was measured by Pentacam. Drop-test was performed over a period of 60sec. Blinks were filmed by high-speed video from a temporal-inferior view to analyse OB (Fig. 1) and LL margin movement (z-axis). UL tear meniscus depth (UL-TMD; horizontal width between UL margin and cornea; z-axis) was observed in the opened eye and almost closed eye via a mirror and slit lamp microscope. Image J Software was used for digital analysis of TMD and LL movement. OB was simulated in vitro by a dynamic blink model (glass-plates (=lids and cornea; saline solution = tear film (TF)). Results In-vivo: median lid margin thickness was 1.8mm (LL) and 1.9mm (UL), but not significant different (p=0.258). Lissamine green drops stayed unaltered in all subjects. Median OB grade was 3. The LL margin tightened in blinks by 1.2mm (median) but this was not related to OB (r=-0.25; p=0.220). Median TMD ratio (TMD almost closed eye / TMD opened eye) was 1.8 indicating an increasing separation of the upper eyelid margin from the cornea. This small effect was significantly correlated to OB (r=0.875; p<0.001). TM appeared to retreat slightly behind the UL (in y-axis direction, toward the cul-de-sac). In-vitro: When dynamically simulating OB the in-vitro TMD increased and the in-vitro TM retreated. TF was anchored to the UL by surface tension and mixed with the LL TM even without lid contact. Conclusions Central keratinized lid margins frequently do not touch in spontaneous blinks and it appears that the central keratinized lid margins are not aligned, as is traditionally presumed. This appears not to impact tear film spreading.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".