Retrospective Observational Study of Posterior Keratometry Measured

Retrospective Observational Study of Posterior Keratometry Measured by IOLMaster 700 in Patients With Keratoconus

Keratoconus is a progressive bilateral disease leading to an apical stromal thinning and an irregular astigmatism by a steepening of the cornea, causing visual impairment. The causes are not yet well known, but it seems to be linked to several comorbidities. Keratoconus is a rare and for a long-time asymptomatic condition and its diagnosis needs meticulous screening for the early stages. Detecting it as soon as possible is a goal as it could lead to earlier avoiding of contributing factors such as eye rubbing and earlier treatment if needed.

The gold standard for keratoconus screening and staging is computerized videotography. It gives information about anterior and posterior corneal bulging, steepening, and thinning. It can be completed by anterior segment optical coherence tomography, which can show corneal scarring. Since recently, some biometry devices can give some information about the posterior corneal keratometry trough swept source optical coherence tomography measures. The measurement of the total corneal power instead of an extrapolation lead to better precision in refractive results after cataract surgery in some cases. It also helped to increase our knowledge about posterior corneal astigmatism. In normal eyes, average posterior corneal astigmatism is 0.37 diopters and against the rule in 91 percent of eyes. There is a correlation between the magnitude of anterior and posterior astigmatism.

In keratoconus eyes, several studies have shown that there is an alignment between axes of the anterior and posterior corneal astigmatism. These studies have been performed on computerized videotopography devices.

The goal of this study was to confirm or deny previous observations about posterior astigmatism in keratoconus eyes, and to assess if the rotation of axis between anterior and posterior astigmatism measured by IOL Master 700® can be a good sign for detection of early stages and fruste keratoconus.

Study Overview

• Status: Completed
• Conditions: Keratoconus

• Study Type: Observational
• Enrollment (Actual): 200

Contacts and Locations

Study Locations

• France
  • Montpellier, France, 34295
    • UH Montpellier

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

included all patients having a specialized cornea consultation, in which keratoconus was diagnosed or suspected from November 2018 to May 2020 in the department of Ophthalmology, University Hospital Gui de Chauliac in Montpellier (France),

Description

Inclusion criteria:

- Keratoconus diagnosed on videotopography

Exclusion criteria:

- loss of sight due to another condition than keratoconus, corneal scarring leading to lack or mistaken data, corneal graft, non-keratoconus related corneal ectasia such as post Laser in Situ Keratomileusis (LASIK) ectasia or keratoglobus

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Keratoconus patient; Patient with keratoconus disease diagnosed on videotopography
Healthy patient; Patient consulting for keratoconus screening with no keratoconus on videotopography

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Posterior keratometry	Posterior cylinder and axis measured on biometry	1 day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total keratometry	Total corneal power (cylinder and axis) measured on biometrycompleted by the patient	1 day

Collaborators and Investigators

• Sponsor: University Hospital, Montpellier
• Investigators: Principal Investigator: Arnaud : MUYL CIPOLLINA, Internship of ophthalmology, University Hospitals of Montpellier

Study record dates

Study Major Dates

• Study Start (ACTUAL): November 1, 2019
• Primary Completion (ACTUAL): June 1, 2020
• Study Completion (ACTUAL): June 3, 2020

Study Registration Dates

• First Submitted: June 4, 2020
• First Submitted That Met QC Criteria: June 4, 2020
• First Posted (ACTUAL): June 9, 2020

Study Record Updates

• Last Update Posted (ACTUAL): June 9, 2020
• Last Update Submitted That Met QC Criteria: June 4, 2020
• Last Verified: June 1, 2020

More Information

Terms related to this study

• Keywords: Ophthalmology; Keratoconus
• Additional Relevant MeSH Terms: Eye Diseases; Corneal Diseases; Keratoconus
• Other Study ID Numbers: RECHMPL20_0338

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: NC

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No