Diagnosis and management of iridocorneal endothelial syndrome

The iridocorneal endothelial (ICE) syndrome is a rare ocular disorder that includes a group of conditions characterized by structural and proliferative abnormalities of the corneal endothelium, the anterior chamber angle, and the iris. Common clinical features include corneal edema, secondary glaucoma, iris atrophy, and pupillary anomalies, ranging from distortion to polycoria. The main subtypes of this syndrome are the progressive iris atrophy, the Cogan-Reese syndrome, and the Chandler syndrome. ICE syndrome is usually diagnosed in women in the adult age. Clinical history and complete eye examination including tonometry and gonioscopy are necessary to reach a diagnosis. Imaging techniques, such as in vivo confocal microscopy and ultrasound biomicroscopy, are used to confirm the diagnosis by revealing the presence of "ICE-cells" on the corneal endothelium and the structural changes of the anterior chamber angle. An early diagnosis is helpful to better manage the most challenging complications such as secondary glaucoma and corneal edema. Treatment of ICE-related glaucoma often requires glaucoma filtering surgery with antifibrotic agents and the use of glaucoma drainage implants should be considered early in the management of these patients. Visual impairment and pain associated with corneal edema can be successfully managed with endothelial keratoplasty

Comparison of corneal endothelial mosaic according to the age: the corimmo 3D project

International audienceAim: The human corneal endothelium is a monolayer of flat hexagonal cells. It is a nearly regular hexagonal tessellation during the first years of life, but with age, becomes less regular in shape and size. The aim is to evaluate geometrically the age of an endothelial mosaic.Material and methods: Segmented endothelial mosaics of healthy subjects of different age groups are compared by morphological criteria. The mosaics are studied according to their age group (decades), their age and their location (center or mid-periphery of the cornea). The measures used are: the cell density, the Ripley's L function and the cell area and perimeter density.Results: These measures point out the endothelial cell density decrease, the cell area, perimeter and diameter increase, the cell heterogeneity increase, and the differences between central and mid-peripheral cells increases with age.Conclusion: These measures are able to characterize healthy mosaics

From DMEK to Corneal Endothelial Cell Therapy: Technical and Biological Aspects

The main treatment available for restoration of the corneal endothelium is keratoplasty and DMEK provides faster visual recovery and better postoperative visual acuity when compared to DSAEK. However, the technical challenges related to this technique and the steep technical learning curve seem to prevent the overcoming of DSAEK in favor of DMEK. Furthermore, the outcome of lamellar keratoplasty techniques is influenced by problems related to corneal grafting tissue availability, management, and quality. On the other hand, improvements in the field of cell engineering have opened the way for the use of stem cells-derived corneal endothelial cells with regenerative intent. In this overview, latest findings in endothelial cell engineering are reported, and perspectives of clinical application of mesenchymal stem cells for corneal endothelial replacement and regeneration are evaluated

Evaluation of Bleb Morphology and Reduction in IOP and Glaucoma Medication following Implantation of a Novel Gel Stent

Objective. To evaluate the efficacy and safety of the Xen Gel Stent and provide a macro- and microscopic analyses of bleb morphology. Methods. A prospective 12-month study on patients with primary open-angle glaucoma. Patients underwent implantation of the XEN Gel Stent (Allergan INC, Dublin, Ireland) either alone or combined with a cataract surgery. Biomicroscopy, in vivo confocal microscopy (IVCM), and anterior segment-optical coherence tomography (AS-OCT) were used to assess bleb morphology. Safety parameters were adverse events, best corrected visual acuity, visual field, and corneal endothelial cell loss. A postoperative IOP ≤ 18 mmHg without or on medications was respectively defined as complete and qualified success while an IOP ≥ 18 mmHg was defined as failure. Results. Twelve eyes of 11 patients were evaluated. At one year, 5 out of 10 patients available achieved a complete success while five were qualified success. AS-OCT showed that bleb wall reflectivity was significantly higher in the failure group; IVCM revealed that stromal density was significantly lower in the success group. No safety issues were recorded. Conclusion. Implantation of the XEN Gel Stent appears to be a safe and effective procedure. AS-OCT and IVCM may be helpful in bleb assessment

The corneal endothelium reflected: Studies on surgical damage tot the corneal endothelium and on endothelial specular microscopy

The endothelium is the innermost layer of the cornea. It is a mosaic of hexagonal cells that is only one cell thick. These endothelial cells actively maintain the corneal hydration equilibrium, and hence are very important for its transparency. However, they are vulnerable to trauma, disease, and intra-ocular surgery, because they have a very restricted capacity for cell division. In part II, studies are presented on the reliability of in-vivo examinations of the endothelium with a specific type of specular microscope. We found that after correct calibration and with adequate assessment methods, valid and reproducible measurements of the endothelial cell density (ECD) could be obtained. However, there is a systematic difference between specular microscopic ECDs and donor cornea ECDs that are measured with a different technique. This difference can only in part be explained by optical factors. In part III, in a clinical and an experimental study, no toxic effects on the endothelium of current common applications of the dye trypan blue, in cataract surgery and in eye banks on donor corneas, could be observed. However, caution is warranted, as higher concentrations or longer exposures were found to cause substantial toxicity. In part IV, endothelial cell loss patterns were investigated after selective transplantation of different parts of the cornea (deep anterior and posterior lamellar keratoplasty, DALK and PLK). After DALK, ECD-loss approached normal levels after an initial drop. When however in PLK a posterior lamella including the endothelium was transplanted, ECD-loss continued at an increased level for up to 7 years. The possible consequences of this result for graft survival were discussed

Neuroglobin and cytoglobin distribution patterns in human and canine eye

Globins are a family of heme-containing proteins that reversibly bind gaseous ligands such as oxygen, nitric oxide and carbon monoxide. Neuroglobin (Ngb) and cytoglobin (Cygb) have been recently added to mammalian globin family. The general hypothesis of this dissertation was: The presence of Ngb and Cygb can be detected by biochemical and immunohistochemical methods in different structures of the eye;Ngb immunoreactivity (IR) in the canine retina was located in the ganglion cell layer (GCL), inner (INL) and outer nuclear layers (ONL), inner (IPL) and outer plexiform layers (OPL), photoreceptor inner segments (IS) and retinal pigment epithelium (RPE). Cygb-IR in the canine retina was found in the GCL, INL and ONL, IPL and OPL and RPE. Ngb and Cygb were expressed in the same cells in the GCL and INL. Distribution pattern of Ngb and Cygb in human retina was similar to distribution found in the canine retina;Ngb and Cygb-IR in the human and canine anterior segment structures was detected in the corneal epithelium and endothelium. Furthermore, in the iris, Ngb and Cygb-IR was localized to the anterior border layer and the stroma, iridal sphincter and dilator muscle. In the iridocorneal angle, both Ngb and Cygb were detected in endothelial cells of the human and canine trabecular meshwork and canal of Schlemm in human. In the ciliary body, Ngb- and Cygb-IR was localized to the nonpigmented ciliary epithelium of the pars plana and pars plicata, as well as in ciliary body musculature. Weak Ngb and Cygb-IR was detected in the lens epithelium. Ngb and Cygb distribution was consistent between human and canine anterior segments and was co-localized within the same cells in all structures;Our studies are the first detailed description of Ngb and Cygb presence detected by immunohistochemical methods in different structures of the canine and human eye. Based on Ngb and Cygb localization and their previously reported biochemical features, we hypothesize that Ngb and Cygb may have important roles in scavenging reactive oxygen species and/or facilitating oxygen diffusion in the eye

Topographic analysis of the centration of the treatment zone after Small Incision Lenticule Extraction (SMILE) surgery for myopia and myopic astigmatism and comparison to Femtosecond laser-assisted LASIK (FS-LASIK)

Introduction Corneal refractive surgery reshapes the cornea in order to change its refractive power and correct refractive errors such as myopia, hyperopia and astigmatism. An important factor associated with the postoperative quality of vision is the centration of the treatment zone. A treatment zone that is decentered in relation to the visual axis may affect the functional corneal morphology and therefore the quality of the visual outcome after the treatment. Functional deficits, such as reduced corrected distance and near visual acuity, irregular astigmatism, halos, glare, reduced contrast sensitivity and monocular diplopia are associated with decentered treatment zones, even in cases of subclinical decentration (<1.0 mm). Purpose An argument often expressed by refractive surgeons is that in small incision lenticule extraction (SMILE) a precise centration cannot be guaranteed due to the subjective intraoperative alignment and lack of eye tracking. Therefore, the purpose of this study is to investigate and compare the centration of the treatment zone between eyes treated with SMILE and active eye-tracker assisted femtosecond laser-assisted LASIK (FS-LASIK), and evaluate the pattern of the achieved centration. Methods In the present retrospective study, 69 myopic eyes of 36 patients who underwent SMILE were compared to 69 myopic eyes of 36 patients treated with FS-LASIK. All procedures were performed at the Department of Ophthalmology, Philipps University of Marburg, by a single surgeon using the VisuMax® femtosecond-laser and MEL-80® excimer-laser (Carl Zeiss Meditec AG, Jena, Germany). Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) was used for preoperative and 3-month postoperative topography and pachymetry. The centration of the treatment zone was estimated by the distance of the point of the maximum pachymetric difference (PMPD) on the corneal thickness differential map from the coaxially sighted corneal light reflex (CSCLR; reference point of centration of the treatment zone in SMILE) and the topographic centre of the entrance pupil (EPC; reference point of centration of the treatment zone in FS-LASIK). The distribution of angle K (angular distance between visual and pupillary axis) was assessed preoperatively in both groups by depicting the exact location of the CSCLR in relation to the EPC. The pattern of the achieved centration was evaluated by depicting on a Cartesian plane the location of the PMPD in relation to the EPC. The pattern of the achieved centration was compared to the preoperative pattern of angle K (pattern of the preoperative CSCLR in relation to the EPC). Results In SMILE group, the mean decentration of the treatment zone from the EPC was 0.326 ± 0.196 mm, ranging from 0.014 to 1.062 mm, whereas the centration of the treatment zone demonstrated a nasalization pattern. In FS-LASIK group, the mean decentration of the treatment zone from the EPC was 0.452 ± 0.224 mm, ranging from 0.02 to 1.040 mm, whereas the centration of the treatment zone demonstrated a random pattern. In relation to the CSCLR, the decentration in SMILE was 0.315 ± 0.211 mm, ranging from 0.0 to 1.131 mm, whereas FS-LASIK eyes demonstrated a mean decentration of 0.516 ± 0.254 mm, ranging from 0.103 to 1.265 mm. The decentration from the reference point of its technique (CSCLR in SMILE; EPC in FS-LASIK) was significantly more extended in FS-LASIK group (P < 0.001). The evaluation of angle K based on the location of the preoperative CSCLR in relation to the EPC showed in SMILE group 32 right eyes and 24 left eyes with positive angle K, 2 right eyes and 11 left eyes with negative angle K, and no eyes with 0° angle K. In FS-LASIK group, there were 29 right eyes and 22 left eyes with positive angle K, 3 right eyes and 14 left eyes with negative angle K, and 1 right eye with 0° angle K. In both groups, the location of the preoperative CSCLR demonstrated a nasalization pattern. In SMILE group, the mean distance of the point corresponding to the preoperative CSCLR from the EPC was 0.227 ± 0.121 mm, ranging from 0.014 to 0.602 mm, and in FS-LASIK group was 0.206 ± 0.097 mm, ranging from 0.045 to 0.457 mm. Statistical analysis showed no significant difference between the two groups (P = 0.201). After SMILE, the achieved centration followed the preoperative pattern of angle K in 52 out of 69 eyes (75.36%), whereas only 32 of 69 eyes (46.37%) followed that pattern after FS-LASIK (P < 0.001). Conclusions The centration of the treatment zone as evaluated on corneal thickness differential maps was better for patient-controlled fixation during SMILE compared to active eye tracker-assisted FS-LASIK. Moreover, the results suggest that centring the refractive procedure on the CSCLR (as in SMILE), results in a more natural outcome, which follows the preoperative pattern of angle K as opposed to centring the refractive procedure on the EPC (as in FS-LASIK)