Indications for penetrating keratoplasty in a tertiary referral centre in Canada, 1996-2004
Bibliographic record
Abstract
BACKGROUND: The leading indications for penetrating keratoplasty (PKP) have changed over recent years. This study examined the leading indications for PKP and their trends, comparing these with recently published data from other studies, including a report from our centre examining indications from 1986 through 1995. METHODS: A retrospective chart review was conducted of all patients who underwent PKP in a single practice at the University Health Network, Toronto Western Hospital, between July 1, 1996, and June 30, 2004. RESULTS: A total of 617 patients underwent 794 PKP operations during the 8-year study period. Sufficient documentation was available to include 777 surgeries from 600 patients in this study. Specific indications for PKP were reported and grouped into 16 categories. The leading indication categories for PKP were regraft (209 cases, 26.9%), pseudophakic bullous keratopathy (PBK) (193 cases, 24.8%), primary corneal endotheliopathies including Fuchs' endothelial dystrophy (101 cases, 13.0%), anterior keratoconus (93 cases, 12.0%), and viral or postviral causes (41 cases, 5.3%). Regraft, keratoconus, and Fuchs' endothelial dystrophy each displayed a nonsignificant decreasing trend from 1996 to 2004, and PBK, herpes simplex virus, and mechanical trauma each displayed a nonsignificant increasing trend (p > 0.05 for all). INTERPRETATION: Regraft was the leading indication for PKP at our centre, followed by PBK; these findings were in agreement with data reported in recent literature. The frequency of regraft had increased since a previous study from our centre (1986-1995), and the frequency of PBK had decreased.
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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 | 0.001 | 0.004 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".