Influence of dry eye syndrome on glaucoma diagnostic procedures

Approximately 50-60% of primary open angle glaucoma patients suffer from dry eye and ocular surface disease and have a reduced corneal thickness. The measurements by imaging procedures are weakened by signal noise and perimetry procedures are affected by generalized loss of sensitivity. In dry eye patients, possible influences on new perimetry procedures, such as frequency doubling technology (FDT), flicker-defined form (FDF) perimetry and pulsar perimetry (PP) potentially result from stray light and reduced contrast sensitivity. In glaucoma patients with ocular surface disturbances, measuring procedures with high sensitivity and low specificity should be carefully checked for plausibility by the examiner. Using these procedures uncritically involves the danger of over interpretation in terms of non-existent glaucoma progression. If necessary, eyes should be pretreated with lubricating eye drops or therapy should be switched to preservative-free pressure lowering drops. Afterwards, new control measurements should be taken to exclude glaucoma pseudoprogression.