Study of the factors associated with the presence of white dots in the corneas of regular soft contact lens users from an Asian country

Abstract

Purpose: : To investigate factors associated with the presence of microdot deposits or white dots (WDs) on confocal microscopy in regular soft contact lens (SCL) users.

Methods: : This cross-sectional observational study investigated changes in the cornea in regular SCL users by using an in vivo slit-scanning microscope (ConfoScan 3). Images were analyzed by noting the presence of highly reflective WDs. Factors associated with WDs were analyzed by using an unpaired t test with Welch correction.

Results: : There were 56 SCL wearers. Of these, a group of 10 had WDs (GWD) in various parts of the cornea. They had worn SCLs for 7 to 20 years and had a mean total duration of SCL wear of 13.6 +/- 4.4 years. Their mean age was 35.8 +/- 10.4 years. They were compared with a group of SCL wearers with no evidence of WDs (GNWD). The mean age of GNWD was 29.1 +/- 7.2 years, with a mean duration of SCL use of 8.17 +/- 5.1 years. The two groups were compared in terms of age, total duration of SCL wear (years), duration in hours per week, SCL water content (%), mean cell density in the endothelium and stroma, endothelial cell coefficient of cell size variation, and percentage of hexagonal cells. Only the duration of SCL wear was significantly associated with the presence of WDs (p=0.0042). WDs were most commonly found in the posterior stroma (n = 9). Two patients had WDs in the epithelium, with one of these having WDs in the endothelium. All patients except one with a hazy left eye scan had WDs bilaterally and symmetrically.

Conclusions: : Confocal microscopy allows visualization of WDs in the corneas of Asian regular SCL users. Patients with WDs have a longer history of SCL wear. WDs may represent an early stage of corneal disease or degeneration associated with alterations in cell behavior.