Increased Straylight in Patients With Keratoconjunctivitis Sicca

PURPOSE: (1) To qualify complaints of quality of vision in patients with (severe) keratoconjunctivitis sicca by examining straylight values and (2) to check for an effect of scleral lens wear on straylight.

METHODS: Straylight was measured in 16 patients with severe keratoconjunctivitis sicca using the Oculus C-Quant. In 9 of these patients, scleral lenses were used, and straylight was measured with and without scleral lenses. Other tests included the Schirmer test, visual acuity, the van Bijsterveld score, and a straylight questionnaire.

RESULTS: Patients with keratoconjunctivitis sicca had a mean straylight OD of log(s) = 1.36 ± 0.19 SD and OS of log(s) = 1.45 ± 0.17 SD. Mean age was 56 ± 9.3 SD. This was significantly higher than the mean age-matched normal value of log(s) = 1.10 (P < 0.001). Such a straylight increase is functionally significant. The difference in straylight with and without scleral lenses was 0.06 log units ± 0.02 SD, but this was not statistically significant for OD (P = 0.134) and OS (P = 0.293). No correlation was found between straylight and the van Bijsterveld score on the corneal section for OD (P = 0.326) and OS (P = 0.433).

CONCLUSIONS: Keratoconjunctivitis sicca leads to increased straylight. However, this increase was not correlated to the amount of surface damage graded with the van Bijsterveld score. Further study on the cornea is necessary to determine the source of the increased straylight. Scleral lenses do not have a noteworthy influence on straylight in these patients.