Cupping reversed in 43% of congenital glaucoma eyes, and corneal diameter predicts it

Design

retrospective chart review with multivariable logistic regression and cluster-robust standard errors

Population

1,223 eyes of 775 children operated for primary congenital glaucoma, 1993 to 2023, minimum 1 year follow-up

Primary outcome

postoperative reversal of cup-disc ratio by 0.2 or more

Effect

reversal in 528 of 1,223 eyes (43.2%); per 1 mm larger corneal diameter aOR 0.50 (95% CI 0.42 to 0.59)

A thirty-year chart review covered 1,223 eyes of 775 children operated for primary congenital glaucoma between 1993 and 2023, all with at least a year of follow-up. Reversal was defined as a fall in cup-disc ratio of 0.2 or more, with cluster-robust standard errors for the bilateral cases.

Reversal occurred in 528 eyes, 43.2%. On multivariable analysis the strongest predictors were anatomical and available at presentation: every additional millimetre of baseline corneal diameter halved the odds of reversal (adjusted OR 0.50, 95% CI 0.42 to 0.59), and shorter axial length favoured it. Earlier onset also predicted reversal - neonatal onset adjusted OR 2.03 (1.04 to 3.93) and infantile onset 2.45 (1.30 to 4.60) against late-onset disease. The authors built a scoring system from the model.

Two things follow for clinic. First, a large cup in an infant is not necessarily a permanent measure of damage, and a substantial minority improve once pressure is controlled - which changes what you tell a family on the day of diagnosis, when the cup-disc ratio is often the most frightening number they hear. Second, buphthalmos with a big cornea is the marker of the eye that will not recover its disc appearance, so the counselling should be different in those children from the start. Measure and record corneal diameter and axial length at baseline; they are what the prediction rests on.

• Record baseline corneal diameter and axial length in every child - they predict disc recovery
• Tell families that cupping can improve after pressure control in a substantial minority
• Set different expectations where the cornea is already large: reversal is much less likely
• Re-document the cup-disc ratio at follow-up rather than carrying the baseline figure forward
• Do not use an unchanged cup alone as evidence of uncontrolled pressure in a larger eye

Why it matters

The cup-disc ratio is treated as a fixed measure of damage in these children, and in over 40% of eyes it was not.

Don't overread it

Retrospective single-centre data over 30 years, with the prediction score derived and not externally validated.

The statistics, in plain English

An adjusted odds ratio of 0.50 per millimetre of corneal diameter is a steep gradient - two millimetres larger means roughly a quarter of the odds - and the narrow interval of 0.42 to 0.59 makes it the most reliable finding here. The onset-timing odds ratios have wide intervals (1.04 to 3.93 for neonatal onset), so their direction is more solid than their size. This is retrospective across three decades of changing surgical practice, and the scoring system was derived in the same data, so it will perform worse elsewhere until validated.

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