Dry eyes after photorefractive keratoplasty
Reviewed by Magdalena Popiela

This study examined changes in tear break up time (TBUT), Schirmer test, tear osmolarity and dry eye questionnaire (OSDI) score from prior to photorefractive keratoplasty (PRK), to two months and four months postoperatively. Fifty eyes of 25 patients were examined. Patients used artificial tears up to two months post PRK. All measured parameters showed significant worsening at two months post surgery compared to values measured beforehand, despite the regular use of artificial teardrops. At four months values for Schirmer test and tear osmolarity have improved and were comparable to ones recorded before the PRK. Tear break up time also improved at four months but remained significantly worse compared to prior the surgery. OSDI score followed a reverse trend, where values at four months post PRK were significantly better compared to before the surgery. This study confirms dry eye as a frequent but transient complication of PRK. It is a first report of changes in tear osmolarity in patients undergoing photorefractive keratectomy. 

Evaluation of tear osmolarity changes after photorefractive keratectomy.
Beheshtnejad A, Hashemian H, Kermanshahani A, et al.
CORNEA
2015;34(12):1541-4.