Reliability of Topography Measurements in Keratoconus

Keratoconus Clinical Trial

Official title:

Repeatability and Reliability of Galilei Corneal Topographer Measurements in Keratoconus

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03511495
• Other study ID #: STUDY00007951
• Status: Completed
• Start date: September 11, 2017
• Est. completion date: March 31, 2019

Study information

• Verified date: April 2019
• Source: Milton S. Hershey Medical Center
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

The purpose of this study is to assess the reliability and repeatability of the parameters obtained using the Galilei dual-scheimpflug corneal topographer for monitoring progression in eyes with keratoconus.

Description:

Keratoconus is a progressive corneal degeneration characterized by progressive steepening and thinning of the central or paracentral cornea leading to corneal protrusion and resulting irregular astigmatism and high myopia. This disorder is usually bilateral and is linked to atopy and excessive eye rubbing, although the precise pathophysiology behind development of this condition is unclear. Keratoconus is the most common corneal degeneration in the United States, affecting between 50 and 230 subjects per 100,000 population.

Early diagnosis and appropriate management of keratoconus relies greatly on accurate assessment of corneal topographic measurements. It is therefore imperative that the data obtained via corneal topography devices is accurate and reliable.

The GALILEI Dual Scheimpflug Analyzer integrates Placido disc topography and dual Scheimpflug tomography to assess anterior and posterior corneal curvature data. Although there have been several studies performed assessing the ability of the Galilei to accurately distinguish keratoconus from unaffected eyes and investigating interdevice reliability between the Galilei analyzer and other tomographers, to our knowledge the repeatability of measurements obtained in this population via the Galilei device has been incompletely evaluated to date.

Corneal topography data obtained via the Galilei device is relied upon heavily in clinical decision making for keratoconic patients both in the Hershey Eye Clinic and in a great number of ophthalmology practices world-wide. It is vital that the accuracy and repeatability of these measurements obtained via the Galilei device are investigated.

The primary endpoint to be measured in the study will be the maximum (steepest) and minimum (flattest) keratometry values in the central zone.

Secondary endpoints will be maximum keratometry across the entire area scanned, axis of corneal astigmatism, anterior and posterior best fit spheres in float mode with the diameter set to 8 mm, maximum anterior and posterior elevations, thinnest corneal thickness, and corneal asphericity at 6 mm, root mean square (RMS) of the HOAs, RMS of the third-order coma, coma axis, vertical and horizontal coma and spherical aberration.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 86
• Est. completion date: March 31, 2019
• Est. primary completion date: March 31, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Patientswho are older than 18 years of age

• Patients who are scheduled to undergo Galilei dual-scheimpflug corneal topography testing

• Patients who have been diagnosed with keratoconus

• Measurements with a reported reliability of 'good' from the topographer

Exclusion Criteria:

• Patients who have undergone any prior surgical intervention involving the cornea (i.e. cornea transplant or INTACS, or corneal cross linking)

Related Conditions & MeSH terms

• Keratoconus

Intervention

Diagnostic Test:
• Galilei Corneal Topographer
A series of five measurements via the Galilei corneal topographer of each keratoconic eye in quick succession

Locations

Country	Name	City	State
United States	Penn State Hershey Eye Center	Hershey	Pennsylvania

Sponsors (1)

Lead Sponsor	Collaborator
Milton S. Hershey Medical Center

Country where clinical trial is conducted

United States, 

References & Publications (11)

Anayol MA, Güler E, Yagci R, Sekeroglu MA, Ylmazoglu M, Trhs H, Kulak AE, Ylmazbas P. Comparison of central corneal thickness, thinnest corneal thickness, anterior chamber depth, and simulated keratometry using galilei, Pentacam, and Sirius devices. Cornea. 2014 Jun;33(6):582-6. doi: 10.1097/ICO.0000000000000119. — View Citation

Bawazeer AM, Hodge WG, Lorimer B. Atopy and keratoconus: a multivariate analysis. Br J Ophthalmol. 2000 Aug;84(8):834-6. — View Citation

Crawford AZ, Patel DV, McGhee CN. Comparison and repeatability of keratometric and corneal power measurements obtained by Orbscan II, Pentacam, and Galilei corneal tomography systems. Am J Ophthalmol. 2013 Jul;156(1):53-60. doi: 10.1016/j.ajo.2013.01.029. Epub 2013 Mar 28. — View Citation

Demir S, Sönmez B, Yeter V, Ortak H. Comparison of normal and keratoconic corneas by Galilei Dual-Scheimpflug Analyzer. Cont Lens Anterior Eye. 2013 Oct;36(5):219-25. doi: 10.1016/j.clae.2013.04.001. Epub 2013 Apr 30. — View Citation

Feizi S, Yaseri M, Kheiri B. Predictive Ability of Galilei to Distinguish Subclinical Keratoconus and Keratoconus from Normal Corneas. J Ophthalmic Vis Res. 2016 Jan-Mar;11(1):8-16. doi: 10.4103/2008-322X.180707. — View Citation

Güler E, Yagci R, Akyol M, Arslanyilmaz Z, Balci M, Hepsen IF. Repeatability and reproducibility of Galilei measurements in normal keratoconic and postrefractive corneas. Cont Lens Anterior Eye. 2014 Oct;37(5):331-6. doi: 10.1016/j.clae.2014.04.004. Epub 2014 Jun 14. — View Citation

Holladay JT. Keratoconus detection using corneal topography. J Refract Surg. 2009 Oct;25(10 Suppl):S958-62. doi: 10.3928/1081597X-20090915-11. — View Citation

Jahadi Hosseini HR, Katbab A, Khalili MR, Abtahi MB. Comparison of corneal thickness measurements using Galilei, HR Pentacam, and ultrasound. Cornea. 2010 Oct;29(10):1091-5. doi: 10.1097/ICO.0b013e3181cf98e5. — View Citation

Meyer JJ, Gokul A, Vellara HR, Prime Z, McGhee CN. Repeatability and Agreement of Orbscan II, Pentacam HR, and Galilei Tomography Systems in Corneas With Keratoconus. Am J Ophthalmol. 2017 Mar;175:122-128. doi: 10.1016/j.ajo.2016.12.003. Epub 2016 Dec 18. — View Citation

Park SH, Choi SK, Lee D, Jun EJ, Kim JH. Corneal thickness measurement using Orbscan, Pentacam, Galilei, and ultrasound in normal and post-femtosecond laser in situ keratomileusis eyes. Cornea. 2012 Sep;31(9):978-82. doi: 10.1097/ICO.0b013e31823d03fc. — View Citation

Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998 Jan-Feb;42(4):297-319. Review. — View Citation

* Note: There are 11 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Maximum (steepest) and minimum (flattest) keratometry values in the central zone	Assessment of the steepness of the cornea	Measured at day 0 of study enrollment
Secondary	Thinnest pachymetry	The thinnest area of the cornea	Measured at day 0 of study enrollment