1 Wessex Adult Cystic Fibrosis Service, University Hospital Southampton NHS Foundation Trust, Southampton, UK. Electronic address: theresa.kolaczkowski@uhs.nhs.uk.
2 Department of Paediatrics, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
3 Ophthalmology department, University Hospital Southampton, Southampton, UK; Clinical and Experimental Sciences, University of Southampton, Southampton, UK.
4 Wessex Adult Cystic Fibrosis Service, University Hospital Southampton NHS Foundation Trust, Southampton, UK.