Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

Abstract

Objectives:The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls.Materials and Methods:Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy). Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient.Results:Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198) and gender (M/F: 4/29 vs. 8/32, p=0.366). Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90).Conclusion:The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

<p>Repeatability of OCT-Based versus Scheimpflug- and Reflection-Based Keratometry in Patients with Hyperosmolar and Normal Tear Film</p>

“…Our findings are supported by some other studies: Dogan et al compared the repeatability for a Sirius Scheimpflug device in patients with dry eyes to healthy patients and found excellent agreement of repeated SimK average measurements in both groups. 39 Jensen et al found no statistically significant differences in the K-values of the IOLMaster 700 when comparing repeated measurements with and without different artificial tear drops, although no evaluation of dry eyes was reported. 40 For PCP, both OCT devices had statistically significantly lower means of both average K and astigmatism differences compared to the Scheimpflug device in both groups.…”

<p>Impact of Thermal Pulsation Treatment on Astigmatism Management and Outcomes in Meibomian Gland Dysfunction Patients Undergoing Cataract Surgery</p>

“…Meibomian gland dysfunction (MGD)-associated evaporative dry eye negatively affects ocular surface health through tear film instability, increased tear evaporation, hyperosmolarity, inflammation, and subsequent ocular surface damage. 7 , 8 The unstable tear film affects the quality of optical surface reflections from the cornea on which the keratometric measurements are based, compromising keratometry readings with manual keratometry or advanced devices like placido disc/point-source color light-emitting diode topographers, slit-scan imaging, swept source OCT biometers or Scheimpflug image-based tomographers. 9 , 10 Further, chronic ocular desiccation and deficiency of the tears have also been associated with corneal deformation, most commonly inferior corneal steepening and high astigmatism resembling keratoconus.…”

The repeatability of corneal topography measurements in severe Dry Eye disease

“…In previous reports the investigators assessed the repeatability of central corneal thickness (CCC) by Pentacam and corneal topography measurements by Sirius devices [5,6]. Lee et al reported that CCT undulated in dry eyes and found that ICC was lower in dry eyes than healthy eyes by Pentacam [5].…”

“…It has been postulated that Scheimpflug device includes the precorneal tear film layer in measuring corneal thickness [4]. Previous studies showed that Pentacam was repeatable in both healthy and dry eyes [1,5,6]. However, a study focusing on the change profile of repeated Pentacam measurements in severe dry eye patients is lacking.…”