Repeatability and reproducibility of Cobra HD fundus camera meibography in young adults with and without symptoms of dry eye

Abstract

The inter-session repeatability (ISR), inter-examiner reproducibility (IER) and within-subject variability (WSV) of the Cobra HD fundus camera meibographer were examined in participants with and without dry eye symptoms. Methods: Symptoms were determined based on Ocular Surface Disease Index scores (≥13 being considered symptomatic), and subgroups were compared using the Mann-Whitney U-test. Images of meibomian glands (MGs) from the upper and lower right eyelids were captured by two examiners on the same day (S1) to determine IER. One examiner repeated the measurements on a second day (S2) to obtain the ISR. ISR, IER and WSV were calculated using Friedman, correlation tests and Bland and Altman analyses with mean differences (md) and 95% confidence intervals (CIs), within-subject standard deviations (Sw) and intra-class correlation coefficients (ICC). Results:The ISR experiment included 72 participants (mean age: 23 ± 5 years, range: 19-43, 36 symptomatic). Mean MG loss of the upper (S1: 13.5 ± 9.5%, S2: 12.8 ± 8.5%) and lower eyelids (S1: 7.5 ± 6.9%, S2: 7.3 ± 6.3%) was not significantly different between sessions for all participants, symptomatic and asymptomatic subgroups for both eyelids. The ISR Sw for the upper and lower eyelids was 1.3% and 1.0%; md was 0.7 ± 3.5% (CI:−6.25% to 7.62%) and 0.1 ± 2.1% (CI: −3.94% to 4.17%), respectively. The IER experiment included 74 participants (mean age: 23 ± 5 years, range: 19-43, 37 symptomatic). Mean MG loss of the upper (Examiner 1: 12.7 ± 8.2%, Examiner 2: 13.1 ± 8.0%) and lower eyelids (Examiner 1: 7.0 ± 6.2%, Examiner 2: 7.4 ± 6.2%) was not significantly different between examiners for all participants, symptomatic and asymptomatic subgroups for both eyelids. The IER ICC values were >0.86 for all conditions, Sw was 1.3% and 1.2%, with a md of −0.4 ± 3.2% (CI: −6.65% to 5.90%) and −0.4 ± 2.9% (CI: −6.15% to 5.31%), respectively. The WSV Sw values were <1.4%, and ICC values were >0.89 for both eyelids, examiners and experimental sessions. Conclusions: The Cobra HD fundus camera demonstrates good repeatability, reproducibility and low WSV, and is a reliable clinical instrument for meibography.

Anterior segment optical coherence tomography meibography compared with keratograph meibography

“…The high percentage of points that fell within the clinical limits suggests a strong agreement between the methods and supports the idea that these two techniques can be used interchangeably. For this study, differences exceeding 12.50% were considered as clinically significant 24 . As such, these findings demonstrate that the difference in measurement between the instruments was not clinically significant.…”

“…For this study, differences exceeding 12.50% were considered as clinically significant. 24 As such, these findings demonstrate that the difference in measurement between the instruments was not clinically significant.…”

“…To establish clinical significance using the meiboscore grading schema, based on the minimum step size of 25% between the grades, a difference not greater than 12.5% was needed between measurements. 23,24…”

Ductal Hyperkeratinization and Acinar Renewal Abnormality: New Concepts on Pathogenesis of Meibomian Gland Dysfunction

“…Traditionally, the devices illuminated the tarsal plate from the skin side for seeing the structure of the MGs [ 47 , 48 ]. With the advancement of technology, noncontact infrared photography has been used to assess MG morphology, including BG-4M/DC-4 (Topcon, Tokyo, Japan), the Meibom Pen (Japan Focus Corporation, Tokyo, Japan), the Keratograph 4 (K4) (Oculus, Wetzlar, Germany), the Keratograph 5M (K5M) (Oculus, Wetzlar, Germany), the Meiboviewer 2.0 (Visual Optics, Chuncheon, Korea), and the Cobra HD fundus camera (Scandicci, Firenze, Italy) [ 49 , 50 , 51 , 52 ]. In normal subjects, relatively straight glands can be observed, with those in the upper eyelid ( Figure 2 A) being slenderer and more elongated than those in the lower eyelid ( Figure 2 C).…”

Contact lens wear and follow‐up and its association with signs and symptoms of meibomian gland dysfunction

“…The Cobra HD meibographer requires that the examiner mark the area of the upper and lower eyelids, as well as the area in which the MGs are observed. 37 The software subsequently calculates the percentage and degree of MG loss (0%-100%, 0-4) where scores of 0, 1, 2, 3 and 4 represent no MG loss, <25% loss, 26%-50% loss, 51%-75% loss and >75% MG loss, respectively. 38 A meiboscore ≥2 is considered abnormal.…”