Related Experiment Video
Updated: Jul 10, 2026

Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis
Published on: November 12, 2015
Associations between endothelial cell characteristics and corneal topography findings in different stages of
Ali Hakim Reyhan1, Ayşe Sevgi Karadağ2, Ali Şimşek3
1Department of Ophthalmology, Faculty of Medicine, Harran University, Şanlıurfa, Türkiye. alihakimreyhan@gmail.com.
Purpose:
This study aimed to compare and correlate specular microscope indices and corneal topography indices in different stages of keratoconus.
Methods:
Two hundred forty-six eyes of 123 participants were enrolled in the study. Corneal topography was performed using Sirius (CSO, Italy), with a rotating Scheimpflug camera and a Placido disc topographer. Corneal endothelial cell indices were assessed using a specular microscope (Nidek CEM-530, Japan). Eyes were graded as keratoconus stages 0-4 according to the Amsler-Krumeich classification. Corneal topography and endothelial cell indices were compared among the groups, and the correlations between them were analyzed.
Results:
The mean age of the patients was 23.26 ± 6.75 years (range, 14-47 years). Forty-eight cases were male (39%) and 75 were female (61%). There were no statistically significant age (p = 0.578) or sex ratio (p = 0.529) differences between the groups. Twenty-nine eyes were included in the control group (11.78%), while 41 (16.67%) had stage 1 keratoconus, 88 (35.77%) had stage 2, and 88 (35.77%) had stage 3. Measurement was not possible in stage 4 keratoconus. No statistically significant difference was determined in specular microscopy values according to the stage of keratoconus, except for the number of analyzed cells (NUM) (p > 0.05). The lowest NUM values were observed in stages 1, 2, and 3, with values of 184.34 ± 67.62 cells/mm2, 155.07 ± 59.48 cells/mm2, and 127.06 ± 64.39 cells/mm2, respectively (p = 0.001). In the keratoconus group, weak statistically significant negative correlations were observed between NUM and SimK1, SimK2, KVf, BCVf, KVb, and BCVb, while a weak positive correlation was noted between NUM and central corneal thickness (p < 0.05).
Conclusions:
NUM seems to decrease, while endothelial cell density exhibits no significant changes, with the progression of keratoconus. It appears that as keratoconus index values increase, NUM may decrease in different stages of keratoconus.
Related Concept Videos
Fluid Mosaic Model
Asymmetric Lipid Bilayer
Membrane Domains
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the anterior...
Mechanisms of Membrane Domain Formation
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Types of Membrane Protrusions
The microvilli, an example of stable protrusions, are finger-like projections with a...
Cells of the Epidermis
The cells in all these layers except the stratum basale are called keratinocytes, a type of cell that manufactures and stores the protein keratin. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from...

