In Vivo Confocal Microscopy Findings in Keratoconus (original) (raw)
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In vivo corneal confocal microscopic analysis in patients with keratoconus
International journal of ophthalmology, 2015
To quantify corneal ultrastructure using laser scanning in vivo confocal microscopy (IVCM) in patients with keratoconus and control subjects. Unscarred corneas of 78 keratoconic subjects without a history of contact lens use and 36 age-matched control subjects were evaluated with slit-lamp examination (SLE), corneal topography and laser scanning IVCM. One eye was randomly chosen for analysis. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve structure were evaluated. IVCM qualitatively demonstrated enlarged basal epithelial cells, structural changes in sub-basal and stromal nerve fibers, abnormal stromal keratocytes and keratocyte nuclei, and pleomorphism and enlargement of endothelial cells. Compared with control subjects, significant reductions in basal epithelial cell density (5817±306 cells/mm(2) vs 4802±508 cells/mm(2), P<0.001), anterior stromal keratocyte density (800±111 cells/mm(2) vs 555±115 cells/mm(2), ...
Clinical Optometry, 2016
A 22-year-old Indian female was referred to Sg Buloh hospital with the diagnosis of bilateral keratoconus. On examination, slit lamp biomicroscopy and corneal topography revealed stage 3 keratoconus in the right eye and stage 2 keratoconus in the left eye. Corneal cell morphology in both eyes was evaluated using confocal microscope. In qualitative observation, almost all corneal layers in right eye except endothelium were partially or completely obscured by haze. Additionally, morphological alterations, such as elongation of keratocyte nuclei and cluster of cells, and dark bands in the anterior stroma were observed in right eye. In the left eye, the amount of haze was less, allowing better visibility of the corneal layers compared with the right eye. The dark bands were evident in the posterior stroma. Quantitative analysis showed that anterior and posterior stromal keratocyte density and endothelium cell density were relatively low in the right eye (834.0, 700.5, and 2,133 cells/mm 2 , respectively) compared with the left eye (934.1, 750.6, and 2,361 cells/mm 2 , respectively). In this case, the right eye, exhibiting stage 3 keratoconus, showed more morphological alteration, particularly in the anterior stroma compared with the left eye with stage 2 keratoconus. Increased severity of the disease can explain these differences in corneal cell morphology.
In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus
Journal of Clinical Medicine, 2022
Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechani...
Corneal Cell Morphology in Keratoconus: A Confocal Microscopic Observation
Malaysian Journal of Medical Sciences, 2017
Purpose: To evaluate corneal cell morphology in patients with keratoconus using an in vivo slit scanning confocal microscope. Methods: A cross-sectional study was conducted to evaluate the corneal cell morphology of 47 keratoconus patients and 32 healthy eyes without any ocular disease. New keratoconus patients with different disease severities and without any other ocular co-morbidity were recruited from the ophthalmology department of a public hospital in Malaysia from June 2013 to May 2014. Corneal cell morphology was evaluated using an in vivo slit-scanning confocal microscope. Qualitative and quantitative data were analysed using a grading scale and the Nidek Advanced Visual Information System software, respectively. Results: The corneal cell morphology of patients with keratoconus was significantly different from that of healthy eyes except in endothelial cell density (P = 0.072). In the keratoconus group, increased level of stromal haze, alterations such as the elongation of keratocyte nuclei and clustering of cells at the anterior stroma, and dark bands in the posterior stroma were observed with increased severity of the disease. The mean anterior and posterior stromal keratocyte densities and cell areas among the different stages of keratoconus were significantly different (P < 0.001 and P = 0.044, respectively). However, the changes observed in the endothelium were not significantly different (P > 0.05) among the three stages of keratoconus. Conclusion: Confocal microscopy observation showed significant changes in corneal cell morphology in keratoconic cornea from normal healthy cornea. Analysis also showed significant changes in different severities of keratoconus. Understanding the corneal cell morphology changes in keratoconus may help in the long-term monitoring and management of keratoconus.
Laser Scanning In Vivo Confocal Analysis of Keratocyte Density in Keratoconus
Ophthalmology, 2008
Purpose: Keratoconus is a form of progressive noninflammatory corneal ectasia. Although abnormalities have been documented at every level of the keratoconic cornea, the exact underlying pathophysiologic process remains unknown. This study aimed to determine the keratocyte density in human corneas with keratoconus imaged by laser scanning in vivo confocal microscopy. Design: Prospective cross-sectional study. Participants: Thirty-six eyes of 26 subjects with keratoconus compared with 33 eyes of 33 control subjects. Methods: Subjects were assessed via ophthalmic examination, computed topography, and laser scanning in vivo confocal microscopy.
Imaging Microscopic Features of Keratoconic Corneal Morphology
Cornea, 2016
Purpose: To search for gold-standard histology indicators using alternative imaging modalities in keratoconic corneas. Methods: Prospective observational case-control study. Fourteen keratoconic corneas and 20 normal corneas (10 in vivo healthy subjects and 10 ex vivo donor corneas) were examined. Images of corneas were taken by spectral domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM) before keratoplasty. The same removed corneal buttons were imaged after keratoplasty with full-field optical coherence microscopy (FFOCM) and then fixed and sent for histology. Controls consisted of normal subjects imaged in vivo with IVCM and donor corneas imaged ex vivo with FFOCM. Corneal structural changes related to pathology were noted with each imaging modality. Cell density was quantified by manual cell counting. Results: Keratoconus indicators (ie, epithelial thinning/thickening, cell shape changes, ferritin deposits, basement membrane anomalies, Bowman layer thinning, ruptures, interruptions, scarring, stromal modifications, and appearance of Vogt striae) were generally visible with all modalities. Additional features could be seen with FFOCM in comparison with gold-standard histology, particularly in the Bowman layer region, whereas the combination of SD-OCT plus IVCM detected 76% of those features detected in histology. Threedimensional FFOCM imaging aided interpretation of twodimensional IVCM and SD-OCT data. Basal epithelial cell and keratocyte densities were significantly lower in patients with keratoconus than those in normals (P , 0.0001). Conclusions: Structural and cellular assessment of the keratoconic cornea by means of either in vivo SD-OCT combined with IVCM or ex vivo FFOCM in both cross-sectional and en face views can detect as many keratoconus indicators as gold-standard histology.
Histological Patterns of Epithelial Alterations in Keratoconus
Journal of Ophthalmology, 2020
Purpose. The purpose of this study was to confirm the presence of specific patterns of epithelial response in corneal buttons from keratoconus patients. Methods. This was a retrospective and descriptive study. 90 penetrating keratoplasty specimens obtained from patients diagnosed with keratoconus were evaluated using bright-field microscopy. Morphologically identifiable characteristics including epithelial cell density and epithelial thickness were analyzed on hematoxylin and eosin- (H&E-) and periodic acid of Schiff- (PAS-) stained slides. Results. Three distinctive patterns of epithelial alteration of the central cornea were established. Pattern 3, in which the central epithelium was as thick as peripheral epithelium, was the commonest (44.4%), followed by the pattern 2, defined as central epithelium thinner than periphery epithelium (38.9%), and the uncommonest pattern was number 1, with central epithelium thicker than the periphery (16.7%). Conclusions. Three distinctive histolo...
Endothelial Cell Analysis in Different Grades of Keratoconus. Specular Microscopy Study
Purpose: To compare the endothelial cell density (ECD) and endothelial cell morphology in different grades of keratoconus with normal corneas by specular microscopy scan and to correlate the findings with the parameters of the severity of keratoconus namely the corneal thickness and keratometric readings. Methods: The study included 75 corneas from 75 patients with keratoconus. They are subdivided according to the severity of keratoconus into 3 subgroups: mild, moderate and severe keratoconus including 30, 25 and 20 eyes respectively. ECD, cell morphology values, central pachymetry and keratometric values were measured in each cornea and results were compared with the values of the 30 normal corneas. Moreover, endothelial count was correlated with the corneal thickness and keratometric measurements in each studied group. Results: In overall, 105 eyes from 105 patients with mean age of 32± 5.2 years were enrolled. The average of the ECD in mild group was (2830 ± 305) which did not differ significantly from that of the control group (2869 ± 313). Although the ECD in the moderate group (2765 ± 319) was lower than that of the normal corneas; there was no significant difference between them. On the other hand, there was a significant difference in the endothelial count between the severe keratoconic eyes (2453 ± 325) and normal corneas (p<0.001). ECD correlated positively with the corneal thickness and inversely with the keratometric readings in the studied eyes. Qualitative analysis of the corneal endothelial cells in keratoconic eyes showed a significant increase in the extent of polymegethism as compared with controls. The relative frequency of heaxagonal cells in keratoconus was significantly lower than that of controls. Additionally, an increase of various cell shapes was noted, indicating that there was also a significant increase in cellular pleomorphism. Conclusions: Quantitative and qualitative endothelial changes were observed in keratoconic eyes by using specular microscopy. The changes are more prominent in eyes with severe keratoconus. Thus specular microscopy may prove to be noninvasive in vivo technique useful in the diagnosis, grading and follow-up of keratoconus.
Recent developments in keratoconus diagnosis
Expert Review of Ophthalmology, 2018
Introduction: Keratoconus and ectatic corneal diseases represent a hot area of research. The need to enhance diagnosis in order to recognize milder forms of the disease and identify inherent predisposition for ectasia progression has gained significant importance because of refractive surgery and also due to the development of new treatment modalities to treat ectatic corneal diseases. This article discusses the nomenclature related to the diagnostic tests used to characterize keratoconus and ectatic corneal diseases, providing a prospective discussion on the latest developments for the diagnosis and follow up of these conditions, including imaging modalities, biomechanical assessments, and an outlook in genetics and molecular biology. Areas covered: We performed an extensive Pubmed literature search, considering the latest developments in the diagnosis of keratoconus and additional ectatic corneal diseases.
Advances in the diagnosis and treatment of keratoconus
Therapeutic Advances in Ophthalmology, 2021
Keratoconus had traditionally been considered a rare disease at a time when the imaging technology was inept in detecting subtle manifestations, resulting in more severe disease at presentation. The increased demand for refractive surgery in recent years also made it essential to more effectively detect keratoconus before attempting any ablative procedure. Consequently, the armamentarium of tools that can be used to diagnose and treat keratoconus has significantly expanded. The advances in imaging technology have allowed clinicians and researchers alike to visualize the cornea layer by layer looking for any early changes that might be indicative of keratoconus. In addition to the conventional geometrical evaluation, efforts are also underway to enable spatially resolved corneal biomechanical evaluation. Artificial intelligence has been exploited in a multitude of ways to enhance diagnostic efficiency and to guide treatment. As for treatment, corneal cross-linking treatment remains t...