Impact of Corneal Fluorescein Staining on Reading Speed
Varshini Varadaraj, MD, MPH
Varshini Varadaraj, MD, MPH, Sezen Karakus, MD, Priya M. Mathews, MD, MPH, Pradeep Y. Ramulu, MD, Ph.D., Bonnielin S. Swenor, MPH, PhD, Esen K. Akpek, MD.
The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD
Purpose: We aimed to evaluate the impact of corneal punctate epithelial erosions on reading speed.
Methods: This prospective cross-sectional study included 184 literate English-speakers aged ≥50 years with a range of corneal staining as evaluated by the Sjögren's International Collaborative Clinical Alliance grading system (scored 0-3, and an additional point given for each of the following: confluent staining, central staining and presence of filaments). A 77-word IReST paragraph was used to assess short-duration out-loud reading speed, and a 7300-word passage was used to measure silent reading speed. Age-adjusted linear regression models were used to examine the association of worse-eye corneal staining score 0-3, confluent staining, and central staining, in separate models, with short and sustained reading speeds [measured as words per minute (wpm)]. Additionally, an age-adjusted log-linear regression model was used to examine associations between corneal staining score 0-3 and per cent decrease in sustained reading speed.
Results: Mean short-duration and sustained reading speeds by corneal staining category 0-3 are shown in the Figure. For the short-duration out-loud reading test, corneal staining at any level was not associated with reading speed. For the sustained reading test, there was a dose-dependent decrement in reading speed (1+ staining: -35.1 wpm, 95%CI=-61.2 to -9.0, p=0.009; 2+ staining: -37.7 wpm, 95%CI=-68.3 to -7.1, p=0.02; 3+ staining: -40.7 wpm, 95%CI=-65.5 to -15.8, p=0.001), as compared to no staining. In a log-linear model, similar decrements in reading speed were noted (1+ staining: -4.9%, 95%CI=-8.9 to -0.53, p=0.02; 2+ staining: -5.8%, 95%CI=-10.5 to -0.67, p=0.03; 3+ staining: -6.4%, 95%CI=-10.3 to -2.3, p=0.002). The presence of confluent staining and central staining were not associated with change in sustained reading speed. There were no subjects with corneal filaments.
Conclusions: Corneal staining is associated with reduced sustained reading speed in a dose-dependent manner and could potentially be used as an objective surrogate for subjective visual symptoms commonly reported by dry eye patients.