A quarter of eyes developed macular oedema after endothelial cell injection, and the prostaglandin was the clue

Design

Multicentre retrospective clinical cohort study with univariate and Kaplan-Meier analysis

Population

57 eyes of 57 patients undergoing cultured human corneal endothelial cell injection at three Japanese tertiary centres

Primary outcome

Postoperative detection of cystoid macular oedema, its timing, and six-month best-corrected acuity

Effect

Oedema in 15/57 eyes (26.3%); preoperative prostaglandin analogue use in 60.0% of affected vs 14.3% of unaffected eyes (P = .001); all resolved, six-month acuity logMAR 0.44 vs 0.60 (P = .52)

Cultured human corneal endothelial cell injection is a cell therapy alternative to keratoplasty for endothelial failure, and this multicentre retrospective review of 57 eyes at three Japanese tertiary centres asks what happens to the macula afterwards.

Cystoid macular oedema was detected on spectral-domain optical coherence tomography in 15 of 57 eyes (26.3%), predominantly in the early postoperative period. Preoperative prostaglandin analogue use was the strongest associated factor: 60.0% of the eyes that developed oedema had been on one, against 14.3% of those that did not (P = .001), with the Kaplan-Meier separation significant at log-rank P = .002. Glaucoma itself (P = .006), topical glaucoma medication (P = .006) and worse preoperative acuity (P = .003) were also associated. Lens status was not.

All cases resolved with topical non-steroidal anti-inflammatory drops or sub-Tenon triamcinolone, and six-month acuity did not differ between eyes that developed oedema and those that did not (logMAR 0.44 against 0.60, P = .52).

The practical response is straightforward and the authors name it: review prostaglandin analogues before the procedure and image the macula afterwards as routine. The important caveat is theirs too - preoperative macular status was undetermined in 50 of the 57 eyes, so some of this oedema may have been present before anyone injected anything. Given how poor the view is through a decompensated cornea, that is not a trivial gap.

• Ask what glaucoma drops a patient is on before endothelial cell injection, and consider substituting the prostaglandin
• Get a preoperative macular OCT wherever the corneal view permits - most of this cohort had none
• Schedule postoperative macular OCT routinely, not only if vision disappoints
• Treat detected oedema; all cases here resolved and six-month acuity was unaffected
• A poor corneal view is a reason to document the limitation, not to skip the attempt

Why it matters

It identifies a modifiable exposure in the weeks before a procedure that is being adopted as an alternative to keratoplasty.

Don't overread it

Pre-existing oedema could not be excluded in 50 of 57 eyes, so this is a detection rate rather than an incidence.

The statistics, in plain English

Every association here comes from univariate analysis in 57 eyes, which means the factors identified are entangled rather than independent. Glaucoma, glaucoma drops and prostaglandin use are largely the same patients, so the data cannot say whether the prostaglandin causes the oedema or simply marks an eye with glaucoma, prior surgery and a compromised blood-retinal barrier. The missing preoperative macular imaging in 50 of 57 eyes is the more serious limitation: a 26.3% detection rate is not the same as a 26.3% incidence when you could not see the macula beforehand.

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