Changes in meibum composition following plaque bachytherapy for choroidal melanoma.

OBJECTIVES

Dry eye is common when external beam radiation is used for the treatment of choroidal melanoma (CM). As meibum structure and composition have been related to dry eye, we determined if plaque bachytherapy for CM alters meibum composition.

DESIGN

H-NMR spectroscopy was used to measure the lipid composition of meibum.

SETTING

The University of Louisville, Kentucky, USA.

PARTICIPANTS

All 13 participants had CM and one participant had iris melanoma.

MAIN OUTCOME MEASURES

Cholesteryl ester (CE) to wax ester (WE) ratio, amount of meibum esters (ME) and meibum lipid saturation were measured.

RESULTS

ME decreased by 80%±18% (±99% CI) in 11 eyes that were treated compared with the contralateral untreated eye. ME increased by 181% in two eyes that were treated compared with the contralateral untreated eye. The mole % CE/WE for meibum was significantly (p<0.0001) 67% lower in eyes that were irradiated compared with control eyes from donors without CM and were not treated. Plaque brachytherapy induced the de-esterification of CE. The intensity of the meibum double bond resonances did not change significantly (p>0.05).

CONCLUSION

Eyes that had plaque brachytherapy had a lower amount of expressible meibum and a lower CE/WE ratio compared with meibum from the contralateral eye that received no treatment and eyes that did not have uveal melanoma. Both the quality and quantity of meibum should be considered in designing a therapy for dry eye after plaque brachytherapy.