Nidek ConfoScan 4 (Z-Ring) Measurements Over Soft Contact Lenses

Abstract

Thickness measurements with the CS4 (z-ring) were not affected if made over soft contact lenses. The use of a soft lens to buffer the cornea during measurements was effective in eliminating corneal dehydration, preventing staining induced by the z-ring without affecting the corneal thickness measurement. It also enhanced epithelial image brightness, which may improve the accuracy in pachymetry.

Improving Interobserver Variation in Corneal Sublayer Pachymetry Using ConfoScan4 With Z Ring

“…Although there are detailed descriptions about corneal sublayer pachymetry using CS4 with z ring in the literatures, 9,[15][16][17] discrepancy could still happen between observers following the written guideline. Although there are detailed descriptions about corneal sublayer pachymetry using CS4 with z ring in the literatures, 9,[15][16][17] discrepancy could still happen between observers following the written guideline.…”

“…The current study used the most anterior keratocytes as the posterior reference for epithelium, which included the Bowman layer. 17,18,20,21 Our FST solely consisted of stromal structures measured from the most anterior keratocytes to the most posterior keratocytes. 14,22,23 However, the reading of Epi+BT is commensurate with the combined readings of epithelial and Bowman thickness in other studies.…”

“…17 The examiner advanced the z ring until the coupling gel contacted with the cornea through the contact lens, and the autoalignment mode was initiated once the stroma was observed. The z ring adapter was placed in front of a 40· objective lens, and the light intensity of the CS4 was set between 75 and 78.…”

“…15,17 Hence, corneal frame selected by different observers may affect the measurement of corneal sublayer thickness. The CS4 renders the total CT, corneal sublayer thickness, and the confocal images of different corneal structures.…”