Development of a prognostic model for predicting long-term visual acuity after cataract surgery in children with bilateral congenital cataracts: a single centre retrospective, observational study.

BACKGROUND

To evaluate factors influencing best corrected visual acuity (BCVA) in paediatric patients with bilateral congenital cataracts (CC) after cataract extraction and intraocular lens (IOL) implantation, as well as develop a robust model for predicting long-term visual acuity.

METHODS

This retrospective study followed 194 paediatric patients with bilateral CC from January 2008 to December 2021. The endpoint event was defined as a final BCVA < 0.22 Log MAR at the last follow-up, which indicated good outcome. The probability of reaching this endpoint event was modelled using Cox proportional hazards regression analysis and internally validated through 200 iteration of 5-fold cross-validation.

RESULTS

A prognostic model for long-term visual acuity in bilateral CC after surgical treatment was established as follows: ln h(t) = -0.009 × "age at cataract extraction" - 0.015 × "age at IOL implantation" - 2.934 × "without nystagmus at last follow - up" + ln h0(0), in which h0(t) represents the baseline risk equation that can be any non-negative equation for time (t); h(t) represents the probability of the endpoint event occurring at time (t) without any endpoint event occurring before it. The model was visualized using a nomogram and contour plot to facilitate clinical practice. The model demonstrated reasonably accurate discrimination with an area under the receiver operating characteristic curve of 0.712 (95% confidence interval [CI]: 0.589-0.835) and a C-index of 0.797 (95% CI: 0.683-0.911). According to the model, children with bilateral CC had a higher likelihood of achieving a good outcome (BCVA < 0.22 Log MAR) if they underwent cataract extraction before the age of six months (hazard ratio [HR] 1.80, 95% CI: 0.92-3.70), received IOL implantation before the age of thirty-one months (HR 3.70, 95% CI: 1.77-7.80), and presented without nystagmus during their last follow-up visit (HR 11.20, 95% CI: 3.96-31.80).

CONCLUSIONS

This long-term visual acuity prognostic model demonstrates adequate performance for individualized prediction and assists in clinical decision-making. The risk stratification index guides optimal timing for surgery.