# A Pilot Study on Predicting Ocular Hypertension in Chinese Patients Undergoing Femtosecond Laser-Assisted Penetrating Keratoplasty

## TL;DR

This study creates a tool to predict the risk of high eye pressure after a specific corneal transplant surgery in Chinese patients.

## Contribution

The study introduces a new predictive nomogram for ocular hypertension after femtosecond laser-assisted penetrating keratoplasty in Chinese patients.

## Key findings

- The nomogram includes four predictors and achieved a C-index of 0.705 for predicting ocular hypertension.
- High-risk patients identified by the nomogram had significantly higher OHT rates than low-risk patients.
- Calibration curves and decision curve analysis confirmed the model's accuracy and clinical usefulness.

## Abstract

Background: Ocular hypertension (OHT) can lead to corneal transplant failure, yet no predictive model exists for OHT after femtosecond laser-assisted penetrating keratoplasty (Fs-PKP). This study aimed to develop and validate a predictive nomogram for OHT in Chinese patients undergoing Fs-PKP.

Methods: A retrospective cohort study at Nanjing First Hospital included 238 patients who underwent Fs-PKP and were followed up for two years. OHT was defined as postoperative intraocular pressure exceeding 21 mmHg or an increase of more than 10 mmHg from baseline. Twenty-three variables related to recipient, donor, and surgical factors were evaluated. Key predictors were identified using the least absolute shrinkage and selection operator (LASSO) method and multivariate Cox regression, leading to nomogram development and validation via 500 bootstrap resamples.

Results: The final nomogram included four independent predictors: prior PKP history, history of viral ocular disease, history of ocular trauma, and intraoperative plan. The model demonstrated good discrimination with a concordance index (C-index) of 0.705 (95% CI: 0.646-0.764), consistent after Bootstrap resampling (C-index: 0.705, 95% CI: 0.648-0.747). Time-dependent receiver operating characteristic analysis at 6, 12, and 24 months showed areas under the curve ranging from 0.677 to 0.756. Calibration curves indicated strong agreement between predicted and observed outcomes. Decision curve analysis demonstrated clinical usefulness across risk thresholds of 20%-70%. High-risk patients identified by the nomogram had significantly higher OHT rates than low-risk patients (P < 0.001).

Conclusions: The nomogram accurately predicts OHT risk following Fs-PKP in Chinese patients, aiding clinical decision-making by preoperatively identifying high-risk individuals.