Comparison of manual & automated analysis methods for corneal endothelial cell density measurements by specular microscopy

Abstract

PurposeTo determine the reliability of corneal endothelial cell density (ECD) obtained by automated specular microscopy versus that of validated manual methods and factors that predict such reliability.MethodsSharp central images from 94 control and 106 glaucomatous eyes were captured with Konan specular microscope NSP-9900. All images were analyzed by trained graders using Konan CellChek Software, employing the fully- and semi-automated methods as well as Center Method. Images with low cell count (input cells number <100) and/or guttata were compared with the Center and Flex-Center Methods. ECDs were compared and absolute error was used to assess variation. The effect on ECD of age, cell count, cell size, and cell size variation was evaluated.ResultsNo significant difference was observed between the Center and Flex-Center Methods in corneas with guttata (p = 0.48) or low ECD (p = 0.11). No difference (p = 0.32) was observed in ECD of normal controls <40 yrs old between the fully-automated method and manual Center Method. However, in older controls and glaucomatous eyes, ECD was overestimated by the fully-automated method (p = 0.034) and semi-automated method (p = 0.025) as compared to manual method.ConclusionOur findings show that automated analysis significantly overestimates ECD in the eyes with high polymegathism and/or large cell size, compared to the manual method. Therefore, we discourage reliance upon the fully-automated method alone to perform specular microscopy analysis, particularly if an accurate ECD value is imperative.

One-year natural course of corneal densitometry in high myopic patients after implantation of an implantable collamer lens (model V4c)

“…However, because the specular microscope evaluates ECD by analysing the central corneal image, which was taken through a central fixation area of the cornea [42,43], peripheral endothelial damage may not be detected. Corneal densitometry assessments by using a Pentacam HR are able to detect various abnormalities in a wider zone than is a specular microscope.…”

Representation of Central Endothelial Cell Density by Analysis of Single Best Specular Microscopy Image Regardless of Cell Size Variance

“…In this study, we adopted only manual analysis due to many previous studies showing that automated ECD analysis significantly overestimates ECD in the eyes with high polymegathism and/or large cell size, compared with manual analysis 5,25,28,29. For the present study, we used only trained and certified reading center graders to perform the specular ECD analysis to eliminate confounding due to inexperience of the grader in performing manual method ECD analysis.…”

“…In order to achieve most reliable ECD values (single best is better than averaging), the graders were to grade on the best quality image of their own choice out of the three. ECD and CV values were evaluated using the Konan center method25–27 in CellChek software. Any eye with very low ECD signifying pathologic endotheliopathy (ECD ≤ 800 cells/mm 2 ) were excluded from analysis.…”

Morphological features of the corneal endothelium in patients with pseudoexfoliative glaucoma

“…Обсуждение В настоящее время в клинической практике используют несколько разновидностей бесконтактных эндотелиальных микроскопов различных производителей, позволяющих проводить точную и безопасную для пациента оценку состояния эндотелиального слоя роговицы. Каждый из этих приборов имеет свои технологические особенности, программное обеспечение и способность работать в автоматическом и/или полуавтоматическом режимах, что в конечном счёте отражается в цифровых величинах результатов исследований, а также в их повторяемости [23][24][25][26][27]. В нашем исследовании морфологию роговичного эндотелия оценивали при помощи бесконтактного эндотелиального микроскопа (ЭМ) ЕМ 935 (Haag Streit, Швейцария) в полуавтоматическом режиме.…”