Repeatability of corneal densitometry measurements using a scheimpflug camera in healthy normal corneas

Pakbin, Mojgan; Khabazkhoob, Mehdi; Pakravan, Mohammad; Fotouhi, Akbar; Jafarzadehpur, Ebrahim; Aghamirsalim, Mohamadreza; Hashemi, Hassan

doi:10.4103/joco.joco_173_21

Cited by 6 publications

(9 citation statements)

References 23 publications

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“…Furthermore, the repeatability of the measurement of the transparency in the middle layer of the cornea was better than that in the posterior and anterior layers of the cornea. These findings are in accord with the results of previous (intra-day) studies on cohorts of subjects with keratoconus 17 , 23 , and among healthy subjects 6 , 17 , 18 , 23 . However, to the best of our knowledge, no studies have been carried out to determine the inter-day repeatability of corneal densitometry measurements and thus, the results from this investigation cannot be compared.…”

Section: Discussionsupporting

confidence: 92%

“…The findings of this study also show that measurements of the transparency of the middle 0–2 and 2–6-mm annular zones have better repeatability than the more outer zones (6–10 and 10–12 mm). The poorer repeatability in the more peripheral zones could be explained by the inclusion of the limbal and sceral area in the analysis, particularly in eyes with diameters less than 12 mm 18 . Another explanation could be that eyelids and lashes have a negative effect on the measurements.…”

Section: Discussionmentioning

confidence: 99%

“…A few studies have been carried out on the intra-day repeatability of densitometry in subjects with keratoconus 16 , 17 , and in healthy subjects 6 , 18 . However, as clinical measurements are compared over time, the inter-day repeatability is more relevant.…”

Section: Introductionmentioning

confidence: 99%

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The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls

Gustafsson

Bizios

Ivarsen

et al. 2023

Sci Rep

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The healthy cornea is transparent, however, disease can affect its structure, rendering it more or less opaque. The ability to assess the clarity of the cornea objectively could thus be of considerable interest for keratoconus patients. It has previously been suggested that densitometry can be used to diagnose early keratoconus, and that the values of densitometry variables increase with increasing disease severity, indicating that densitometry could also be used to assess progressive keratoconus. Previous studies have only assessed the repeatability of corneal densitometry measurements on the same day, which does not reflect the clinical setting in which changes are evaluated over time. We have therefore evaluated the inter-day repeatability of densitometry measurements in both patients with keratoconus and healthy controls. Measurements in the middle layer of the 2–6 mm zone of the cornea showed the best repeatability. Although an objective measure of the corneal transparency could be interesting, the generally poor repeatability of densitometry measurements limits their use. The repeatability of corneal clarity measurements could be improved by using other approaches such as optical coherence tomography, but this remains to be investigated. Such improvements would allow the more widespread use of corneal densitometry in clinical practice.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls

Gustafsson

Bizios

Ivarsen

et al. 2023

Sci Rep

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show abstract

“…During the examination, the patient remains in a standardized dim-light condition for 5-10 min and is subjected to the test in the natural state of the pupil ( Pakbin et al, 2022 ). The patient, who is seated with their chin fixed on a mandibular brace, is asked to stare at a fixed target in the center of the Pentacam blue stripe without blinking or moving their eyes.…”

Section: Measurement Methods Of the Corneal Optical Densitymentioning

confidence: 99%

Corneal optical density: Structural basis, measurements, influencing factors, and roles in refractive surgery

Zeng

et al. 2023

Front. Bioeng. Biotechnol.

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The cornea is the main refractive medium of the human eye, and its clarity is critical to visual acuity. Corneal optical density (COD) is an important index to describe corneal transparency. Intact corneal epithelial and endothelial cells, regular arrangement of collagen fibers in the stroma, and normal substance metabolism are all integral for the cornea to maintain its transparency. In the last two decades, the Pentacam Scheimpflug imaging system has emerged as a breakthrough for the measurement of COD (also called corneal densitometry). It has been found that a wide variety of factors such as age, refractive status, and corneal diseases can affect COD. Different corneal refractive surgery methods also change COD in different corneal regions and layers and affect visual acuity following the surgery. Thus, COD has gradually become a significant indicator to evaluate corneal health, one on which the attention of clinicians has been increasingly focused.

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“…Scheimp ug cameras, such as the Pentacam (Oculus Optikgeraete GmbH; Wetzlar, Germany), have gained popularity as tools for assessing CD in healthy human eyes (4,(7)(8)(9)(10), and in various diseases, including diabetes mellitus (11), corneal infections (6), keratoconus (12), Fuchs endothelial dystrophy (13), refractive surgery (14,15), and keratoplasty (16,17).…”

Section: Introductionmentioning

confidence: 99%

Corneal Densitometry Measurements Comparison between Anterior Segment OCT and Scheimpflug Imaging

Lupardi,

Moramarco,

Cassini

et al. 2024

Preprint

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Purpose: To evaluate and compare the repeatability of corneal densitometry (CD) measurements obtained using both an anterior-segment optical coherence tomography (AS-OCT) device and a Scheimpflug camera system, while also assessing the level of agreement. The study also sought to investigate the correlation of CD with age, gender, and central corneal thickness (CCT) in normal eyes. Methods: CD measurements were obtained using the Casia 2 and the Pentacam AXL Wave. Data were collected on total corneal densitometry (TCD) and 4 concentric corneal annular areas, these are referred to as zone 1, denoting the central area, through to zone 4, designating the outermost peripheral region. Repeatability was assessed using intra-session test-retest variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). The agreement was evaluated using Bland-Altman plots. Correlation analysis was performed between CD, age, gender, and CCT. Results: The study included 96 healthy volunteers. The Casia 2 demonstrated high repeatability and lower CoV values compared to the Pentacam AXL Wave. Agreement between the instruments was high in all corneal zones except for zone 1. CD values were positively correlated with age, except for zone 1 with the Pentacam. Conclusions: The findings suggest that the Casia 2 can be a reliable tool for assessing corneal transparency in healthy individuals, however its measurements are not interchangeable with those provided by the Pentacam. The AS-OCT device may be more sensitive in detecting subtle age-related changes in CD within the central zone.

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Repeatability of corneal densitometry measurements using a scheimpflug camera in healthy normal corneas

Cited by 6 publications

References 23 publications

The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls

The intra- and inter-day repeatability of corneal densitometry measurements in subjects with keratoconus and in healthy controls

Corneal optical density: Structural basis, measurements, influencing factors, and roles in refractive surgery

Corneal Densitometry Measurements Comparison between Anterior Segment OCT and Scheimpflug Imaging

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