Clinical and specular microscopic manifestations of iridocorneal endothelial syndrome

Posterior corneoscleral limbus: Architecture, stem cells, and clinical implications

The limbus is a transition from the cornea to conjunctiva and sclera. In human eyes, this thin strip has a rich variation of tissue structures and composition, typifying a change from scleral irregularity and opacity to corneal regularity and transparency; a variation from richly vascularized conjunctiva and sclera to avascular cornea; the neural passage and drainage of aqueous humor. The limbal stroma is enriched with circular fibres running parallel to the corneal circumference, giving its unique role in absorbing small pressure changes to maintain corneal curvature and refractivity. It contains specific niches housing different types of stem cells for the corneal epithelium, stromal keratocytes, corneal endothelium, and trabecular meshwork. This truly reflects the important roles of the limbus in ocular physiology, and the limbal functionality is crucial for corneal health and the entire visual system. Since the anterior limbus containing epithelial structures and limbal epithelial stem cells has been extensively reviewed, this article is focused on the posterior limbus. We have discussed the structural organization and cellular components of the region beneath the limbal epithelium, the characteristics of stem cell types: namely corneal stromal stem cells, endothelial progenitors and trabecular meshwork stem cells, and recent advances leading to the emergence of potential cell therapy options to replenish their respective mature cell types and to correct defects causing corneal abnormalities. We have reviewed different clinical disorders associated with defects of the posterior limbus and summarized the available preclinical and clinical evidence about the developing topic of cell-based therapy for corneal disorders.

Clinical and Specular microscopy characteristics and corelation in Iridocorneal endothelial syndrome without corneal edema

PURPOSE

To investigate endothelial imaging patterns in ICE syndrome and correlate these with the observed clinical features in the affected eye.

METHODS

Of the 70 patients of ICE syndrome referred from the glaucoma clinic between 2017 and 18, 17 patients had a clear cornea for reliable endothelial imaging were included in the study.

RESULTS

Mean age was 47(range 29-63) years; 9 males and 8 females. The right eye was involved in 10 and left eye in 7 patients. Mean best corrected visual acuity was 20/30 (20/20-20/80) in the affected eye. All 17 patients had clear and compact central cornea and reasonably good vision at the time of specular microscopy. Those with best corrected visual acuity <20/20 had cataract as a co-morbidity. Endothelial abnormalities were noted in all patients and were documented using Hirst and modified Sherrard's classification system. As per the modified Sherrard's classification system, 9 eyes were categorised into total ICE, 5 eyes into subtotal ICE, in 3 eyes grading could not be applied. Of the 4 subtotal ICE, 1 was subtotal ICE (+) and 3 were subtotal ICE (-). 12/17 patients had glaucomatous disc.

CONCLUSIONS

Specular microscopy provides information on the various morphological pattern of endothelial abnormalities and helps in mapping out the areas with abnormal/diseased endothelium. These have implications in the management of ICE syndrome.

Surgical outcomes of Ahmed glaucoma valve implantation in patients with glaucoma secondary to iridocorneal endothelial syndrome

OBJECTIVES

To evaluate the long-term outcome of patients with iridocorneal endothelial (ICE) syndrome who underwent Ahmed glaucoma valve implantation surgery for uncontrolled glaucoma.

METHODS

Eighteen patients who suffered from unilateral ICE syndrome with uncontrolled glaucoma and subsequently underwent Ahmed aqueous shunt surgery at Zhongshan Ophthalmic Center between January 2008 and December 2016 were reviewed. Outcome measures included intraocular pressure (IOP), the use of glaucoma medications, visual acuity, further surgical interventions, and surgical complications.

RESULTS

The mean IOP was reduced from 34.8 ± 10.6 mmHg on 3.6 ± 0.5 medications to 17.4 ± 4.9 mmHg (t = 6.791, P = 0.000) on 1.6 ± 1.1 medications (Z = -3.545, P = 0.000) at the last follow-up (42.0 ± 19.3 months). Five eyes (27.8%) achieved complete success, nine (50.0%) achieved qualified success, and the remaining four (22.2%) were considered failures. Survival was 94.4% at 1 year, 88.1% at 2 years, and 73.5% at 3 years. Four cases displayed a flat anterior chamber and were treated with a single anterior chamber reformation surgery with no recurrence. No other complications related to the glaucoma drainage implants occurred in this series.

CONCLUSIONS

Ahmed glaucoma valve implantation appears to be a safe and effective method for treating glaucoma secondary to ICE syndrome. Postoperative shallow anterior chamber and hypotony may occur but responds well to the treatment. Early consideration may be given to aqueous shunt surgery in patients with glaucoma secondary to ICE syndrome when trabeculectomy fails.

Cogan-Reese syndrome: image analysis with specular microscopy, optical coherence tomography, and ultrasound biomicroscopy

Iridocorneal endothelial (ICE) syndrome is a progressive clinical spectrum of corneal endothelial abnormalities affecting the cornea, iris, and iridocorneal angle. Three clinical variations are recognized: essential (progressive) iris atrophy, Chandler syndrome, and Cogan-Reese syndrome. Direct slit-lamp visualization of the cornea and anterior segment in cases of ICE syndrome is inadequate for precise and objective assessment of the affected structures. We describe the evolution of corneal and anterior segment structural changes in a woman with Cogan-Reese syndrome using three different methods of image analysis: specular microscopy, anterior segment optical coherence tomography, and ultrasound biomicroscopy.

Iridocorneal endothelial syndrome: Evaluation of patient demographics and endothelial morphology by in vivo confocal microscopy in an Indian cohort

Purpose:

To evaluate the patient demographics and morphological characteristics of corneal endothelium by in vivo confocal microscopy (IVCM), in patients with Iridocorneal Endothelial (ICE) Syndrome.

Methods:

In this retrospective observational series, IVCM acquired endothelial images of patients with ICE syndrome were evaluated. ‘ICE cells’ morphology was classified as “−” or “+” if they were larger or smaller than contralateral normal endothelium. It was correlated with patient demographics and clinical manifestations.

Results:

IVCM was performed on 41 eyes of 21 patients, with 13 males (62%) and 8 females (38%). The disease was unilateral in 19 (90.5%) and bilateral but asymmetric in two (9.5%) patients. Total ICE was seen in 91% eyes. Eighty percent patients (12 out of 15) with ICE—cells were males while 83.3% (5 out of 6) patients with ICE + cells were females. Mean age of patients with ICE- cell type and ICE + cell type was 45.8 ± 17.8 years and 40.3 ± 9.2 years respectively (P = 0.02). Both ICE – and ICE + eyes had similar incidence (33.3%) of corneal edema. ICE + eyes had more severe (grades 2/3) glaucoma (n = 5/6 eyes, 83.3%) compared to ICE – eyes (n = 8/15 eyes, 53.3%).

Conclusion:

A male preponderance, predilection of ICE – and + cell variants for male and female gender respectively, lack of association of the endothelial cell morphology with corneal edema, and apparent association of ICE + phenotype with more severe glaucoma occurring at a relatively younger age, are some novel findings of the present study. In the clinical setting correlation of patient demographics with these IVCM findings may help in better long-term prognostication of eyes with ICE syndrome.

Corneal endothelial cell dysfunction: etiologies and management

A transparent cornea is essential for the formation of a clear image on the retina. The human cornea is arranged into well-organized layers, and each layer plays a significant role in maintaining the transparency and viability of the tissue. The endothelium has both barrier and pump functions, which are important for the maintenance of corneal clarity. Many etiologies, including Fuchs’ endothelial corneal dystrophy, surgical trauma, and congenital hereditary endothelial dystrophy, lead to endothelial cell dysfunction. The main treatment for corneal decompensation is replacement of the abnormal corneal layers with normal donor tissue. Nowadays, the trend is to perform selective endothelial keratoplasty, including Descemet stripping automated endothelial keratoplasty and Descemet’s membrane endothelial keratoplasty, to manage corneal endothelial dysfunction. This selective approach has several advantages over penetrating keratoplasty, including rapid recovery of visual acuity, less likelihood of graft rejection, and better patient satisfaction. However, the global limitation in the supply of donor corneas is becoming an increasing challenge, necessitating alternatives to reduce this demand. Consequently, in vitro expansion of human corneal endothelial cells is evolving as a sustainable choice. This method is intended to prepare corneal endothelial cells in vitro that can be transferred to the eye. Herein, we describe the etiologies and manifestations of human corneal endothelial cell dysfunction. We also summarize the available options for as well as recent developments in the management of corneal endothelial dysfunction.

Unique variations and characteristics of iridocorneal endothelial syndrome in China: a case series of 58 patients

PURPOSE

Iridocorneal endothelial (ICE) syndrome is a rare condition, and unique characteristics in Chinese patients can make diagnosis difficult. Our purpose was to describe the clinical characteristics and variations of ICE syndrome in 58 consecutive Chinese patients.

METHODS

The clinical data of consecutive patients with ICE syndrome who were seen between 2008 and 2011 at the glaucoma clinic of our ophthalmology department were retrospectively reviewed. The diagnostic criteria for ICE syndrome were a "hammered-silver" appearance of the corneal endothelium and specular microscopy showing ICE cells characterized by the absence of a hexagonal appearance, dark areas within the cells, and a light-dark reversal pattern. The general characteristics of the cornea, iris, pupil, and anterior chamber angles were compiled and examined.

RESULTS

Fifty-eight patients with ICE syndrome were identified: 26 had Chandler's syndrome (CS), 23 Cogan-Reese syndrome, and nine progressive iris atrophy (PIA). The incidence of glaucoma was 98%. Twenty-three (39.7%) patients had atypical ICE syndrome. Intraocular pressure was relatively high in 13 patients with slightly damaged irises, while the corneal endothelium remained relatively intact. Slit lamp examination showed an intact iris in ten patients (17.2%), with massive deposition of black pigment in the anterior chamber angle. In the 25 patients in whom the anterior chamber angle was only partially closed, 80% of the anterior chamber angles were hyperpigmented.

CONCLUSIONS

CS is the most common variation of ICE syndrome in Chinese patients, and PIA is the least common. A slight change or an intact iris under slit lamp examination is a characteristic of ICE syndrome.

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.

Atypical angle closures

PURPOSE OF REVIEW

Primary angle closure typically causes acute intraocular pressure rise in the phakic elderly. Alternative diagnoses, however, for which iridotomy is usually ineffective, occur commonly in younger, nonhyperopic, and pseudophakic patients.

RECENT FINDINGS

High-resolution ultrasonography has advanced our understanding of these entities. Management of platueau iris, present in over half of angle closures with patent iridotomy, may depend on disease stage. Early postoperative pseudophakic patients with myopic shift and narrow angle should be treated with laser capsulotomy for capsular block. Bilateral angle closure is usually due to an offending systemic pharmacologic agent, which must be stopped to resolve the closure. Ciliary body swelling often produces angle closure by blocking the access of aqueous to the anterior chamber, sometimes paradoxically after hypotony. Annular choroidal effusions, difficult to detect without ultrasound, may mimic angle closure. Although cycloplegic and corticosteroid therapy may resolve some entities, pars plana vitrectomy and lensectomy may be necessary to resolve severe ciliary block. We also discuss unique variants of angle closure in patients with retinal disease.

SUMMARY

Atypical angle closures should always be considered. Careful examination techniques and new technology can detect the mechanisms involved and direct treatment.

Le glaucome du syndrome irido-cornéo-endothélial

Iridocorneal endothelial (ICE) syndrome is a group of ocular conditions characterized by corneal proliferative endotheliopathy in which secondary corneal edema, peripheral anterior synechiae, and abnormalities of the iris stroma are the common features. The etiology remains unclear, but may be related to viral infection with Herpes simplex or Epstein-Barr virus. The pathogenesis of the ICE syndrome is believed to result from an abnormality of the corneal endothelial cells (causing corneal edema), with secondary spreading of the cells over the trabecular meshwork region (causing anterior synechiae and elevated intraocular pressure [IOP]) and across the surface of the iris (responsible for the formation of iris holes, pupillary distortion, and iris noduli). The disease complex, which includes essential iris atrophy, Chandler's syndrome, and iris nevus (Cogan-Reese) syndrome, is almost always unilateral, nonfamilial, and typically occurs in females during young adulthood. ICE syndrome is commonly progressive and frequently complicated by secondary glaucoma and corneal decompensation. In Chandler's syndrome, iris changes are less pronounced and corneal edema more frequent than in essential iris atrophy or Cogan-Reese syndrome. Glaucoma associated with ICE syndrome is often difficult to manage and is usually treated with medications and/or filtering surgery. Glaucoma filtering surgery is usually successful when done early, but may fail due to endothelialization of the fistula by the abnormal corneal endothelium.

In vivo confocal microscopic characteristics of iridocorneal endothelial syndrome

PURPOSE

To analyse five cases of iridocorneal endothelial (ICE) syndrome and describe the microstructural characteristics observed by in vivo confocal microscopy.

METHODS

All five subjects presented with clinical characteristics suggestive of ICE syndrome and were examined clinically by Orbscan II pachymetry and by in vivo confocal microscopy. At least 600 sequential digital confocal images throughout the z-axis were analysed qualitatively and quantitatively for each cornea.

RESULTS

Clinically, all subjects presented with: minimal to moderate corneal oedema, focal to diffuse 'beaten metal' appearance of the corneal endothelium, and varying degrees of iris atrophy. Three subjects had a history of elevated intraocular pressure. In vivo confocal microscopy highlighted two main patterns of endothelial change: small cells (mean maximal diameter of 13.6 +/- 1.5 micro m), with indistinct borders and very bright and prominent, uniform nuclei (two subjects) and larger, epithelioid-like cells (mean maximal diameter of 26.6 +/- 5.5 micro m), with irregular borders and non-homogenous, diversely shaped nuclei (three subjects). Different degrees of alteration of stromal structure, very prominent corneal nerves and unusual syncytia of keratocytes were also observed. Significant oedema of the basal epithelium with increased reflectivity of the intercellular spaces was prominent in all cases.

CONCLUSIONS

Although ICE syndrome is considered to be primarily an endothelial disease, in vivo confocal microscopy demonstrated structural alterations throughout the entire cornea even in clinically mild cases. The ability of in vivo confocal microscopy to localize and accurately measure various elements in different corneal layers will assist differentiation of various presentations of ICE syndrome as this technique becomes increasingly available in clinical practice.