Abstract
Purpose:
To determine if there are differences in dry eye signs and symptoms among healthy patients group (control) and an affected keratoconus group (KC), before surgery (pre). Also, to identify the surgery effects on dry eye signs and symptoms, assessing the symptoms before (pre) and after (post) the intrastromal corneal ring segments (ICRS) insertion
Methods:
We included 15 patients (15 eyes) with KC and Kerarings ® intrastromal rings implanted, while the control group consisted of 16 healthy subjects (16 eyes). Schirmer test without anesthesia, BUT, corneal staining, OSDI questionnaire and the concentrations of diadenosine tetraphosphate (Ap4A) from samples collected through Schirmer tear strips were evaluated. Goblet cells density, mucin cloud height (MCH) and thickness of the cell (CLT) were measure using impression cytology by means of the Eye Prim medical device. All measurements were performed before (pre) surgery, one month after (post) and at 6 months (post6m) to assess the evolution of the changes in time.
Results:
The values obtained from Schirmer test indicate that patients with KC show statistically lower tear volume, 5.70 ± 3.74 mm, than healthy patients, 12.44 ± 8.83 mm, whereas no statistical differences were found when compared before and after implementing the ICRS group in KC. We found no differences in BUT, or in the evaluation between control groups and KC group before or after ICRS surgery. At OSDI, KC patients showed scores 44.96 ± 8.65 before surgery, decreasing to 19.31 ± 4.28 value, 6 months after surgery. KC patients presented statistically significant more corneal staining than subjects in the control group. In addition, KC patients presented very high concentrations of Ap4A, 2.56 ± 1.10 mM, compared to the control group 0.15 ± 0.12 uM, while at 6 months the concentration decreased to 1.02 ± 0 65 uM. Finally, in KC group the goblet cells cell density was 21.2 ± 8.02 cells/mm2 compared to the control 32.22 ± 12.59 cells/mm2, and further decreasing after ICRS surgery. On the contrary, the mch increased at 6 months after surgery, with no statistically significant differences between KC and control group.
Conclusions:
Keratoconus patients present more symptoms and signs of dry eye than healthy subjects. It seems that ICRS surgery induces changes improving dry eye symptoms in KC patients.
Keywords: 574 keratoconus •
550 imaging/image analysis: clinical •
486 cornea: tears/tear film/dry eye