Steffi Knappe

Results of Confocal Microscopy Examinations after Collagen Cross-Linking with Riboflavin and UVA Light in Patients with Progressive Keratoconus

Purpose: Keratoconus is a predominantly bilateral form of corneal degeneration that is associated with central thinning and cone-shaped bulging of the cornea usually accompanied by a progressive reduction in visual acuity. A recent therapeutic option is cross-linking, a procedure designed to prevent the progression of keratoconus by the photochemical cross-linkage of collagen fibers. Patients and Methods: Eight eyes in 8 patients with progressive keratoconus were treated by the photochemical cross-linking method using riboflavin and UVA light. In addition to the usual ophthalmological examinations, patients were examined pre- and postoperatively by confocal in vivo laser scanning microscopy. Follow-up examinations were performed at 2 weeks and at 2, 4, 6 and 12 months postoperatively. Results: Complete regeneration of corneal epithelium was detected by 2 weeks after therapy at the latest. The sub-basal nerve plexus could not be visualized by confocal microscopy after treatment. Immediately after treatment, the anterior corneal stroma had a honeycombed appearance but without the typical hyperreflective keratocyte nuclei. At about 6 months postoperatively, the corneal stroma had virtually regained its normal configuration. After therapy, confocal microscopy revealed that corneal endothelium was normal in terms of cell density and morphology at every time point. Conclusions: Confocal in vivo laser scanning microscopy is an investigative technique that permits reproducible visualization of structural changes in the cornea (epithelium, stroma and endothelium) following collagen cross-linking with riboflavin and UVA light. Once epithelial healing is complete, the epithelium and endothelium appear to be unaffected by the treatment. The most noteworthy structural changes, which are detected on confocal microscopy shortly after treatment, involve the anterior and middle corneal stroma. Over the course of time, up to 12 months postoperatively, these changes show a definite tendency to regress.

Short-term corneal response to cross-linking in rabbit eyes assessed by in vivo confocal laser scanning microscopy and histology.

Purpose: Corneal cross-linking for the treatment of keratoconus has been tested in animal trials and proven clinically. A combination of in vivo confocal laser scanning microscopy (CLSM) and histology was used in rabbit corneas to assess early modifications at the cellular level after corneal cross-linking. Methods: Twelve New Zealand male rabbits were tested; in each case, the right eye was the study eye and left eye was the control eye. In vivo CLSM was performed on both eyes before and at 3 days and 1 week after cross-linking. Keratocyte and endothelial cell densities were determined by CLSM before and after cross-linking. After CLSM, the corneas were excised and processed for histology and immunohistochemistry. Results: Massive edema was observed 3 days after cross-linking. The corneal epithelium had already closed again by day 3. No cellular structures were detected in the stroma and endothelium. One week after cross-linking, normal corneal transparency and thickness were restored. The anterior stroma still lacked nuclei. The number of nuclei in the posterior stroma was significantly lower than that in the intact corneas. Highly reflective spindle-shaped structures were detected in the posterior stroma. The endothelial monolayer had closed again but still showed significantly decreased cell density. At 1 week after cross-linking, immunohistochemical staining revealed the presence of proliferating cells in the corneal epithelium, posterior stroma, and endothelium. Conclusions: The early response of the rabbit cornea to cross-linking was successfully characterized at the cellular level by in vivo CLSM and histology, and the results obtained with both techniques correlated positively.

Epidemic keratoconjunctivitis. In vivo images of corneal structures with the confocal Rostocker laser scanning microscope (RLSM)

ZusammenfassungHintergrundDie Keratoconjunctivitis epidemica ist eine hochkontagiöse Erkrankung, die durch Adenoviren vom Typ 8, 19 und 37 verursacht wird. Durch die Ausbildung subepithelialer Nummuli kann eine jahrelange Visusminderung resultieren. Warum in einigen Fällen die histopathologisch aus Lymphozyten, Histiozyten und Fibroblasten bestehenden Nummuli persistieren, ist bisher nicht genau bekannt. Mit dem konfokalen Rostocker Laser-Scanning-Mikroskop (RLSM) gelingt es in vivo korneale Strukturen durch eine optimale Ortsauflösung zu erkennen und eine exakte Tiefenzuordnung zu treffen.Patient und MethodeUnter besonderer Berücksichtigung krankheitsspezifischer Veränderungen untersuchten wir eine 28-jährige Patientin, die einen typischen Krankheitsverlauf einer KCE zeigte. Zur Verlaufsdokumentation führten wir neben der spaltlampenmikroskopischen Untersuchung eine konfokale Hornhautmikroskopie mit dem RLSM durch und stellten die Untersuchungsbefunde beider Methoden gegenüber.ErgebnisseMit dem RLSM ließen sich in den basalen Schichten des Epithels und auf Höhe des Nervenplexus massenhaft dendritische Zellen sowie punktförmige Strukturen darstellen. Wir vermuten, dass es sich bei den dendritischen Zellen um Langerhans-Zellen handelt.SchlussfolgerungDas RLSM ermöglicht In-vivo-Untersuchungen zur Darstellung kornealer Mikrostrukturen mit präziser Tiefenzuordnung nach einer KCE. Weitere Verlaufsuntersuchungen werden zeigen, welche Bedeutung die sichtbaren Strukturen haben und ob neue Erkenntnisse zur Persistenz der subepithelialen Nummuli gewonnen werden können.AbstractPurposeEpidemic keratoconjunctivitis (EKC) is a highly contagious infection caused by adenovirus types 8, 19, and 37. The formation of subepithelial nummular infiltrates may lead to permanent visual disturbance. These infiltrates consist histopathologically of an accumulation of lymphocytes, histiocytes, and fibroblasts.Patient and methodThe reasons for the persistence of these nummular infiltrates are not fully understood. We examined a 28-year-old female patient with typical signs of EKC infection clinically and additionally with the RLSM.ResultsNummuli were identified by the RLSM as areas with an accumulation of dendritic cells (supposed to be Langerhans cells) as well as so far unidentified punctiform structures located in the basal cell layer and in the region of the subepithelial nerve plexus.ConclusionsThe RLSM allows us to investigate corneal microstructures in vivo with precise depth localization related to epidemic keratoconjunctivitis. Further investigations may disclose the role of dendritic cells in the pathogenesis of the nummular formation as well as their contribution to the variable persistence of partially threatening vision opacities.

Treatment and Pathology of an Unusual Large Carcinoma of the Conjunctiva

Carcinoma of the conjunctiva is a malignant tumor which is mostly detected and surgically treated at an early stage because of medical or cosmetic problems. Exceptions of this rule may occur in developing countries, where patients do not have access to standard medical care systems. We report the case of a conjunctival carcinoma in an African patient with an unusually late presentation. Because of local medical shortcomings, and considering the severe, transmural inflammation of anterior ocular structures, an exenteration was performed although the orbit was not deeply involved with the tumor. The strong nuclear expression of p53 indicates a major role of UV exposure in this case. A total of 16-month follow-up in this patient and larger published series suggest that the risk of metastasis is rather low under those circumstances, even with invasive tumors.

Management of Congenital Clinical Anophthalmos with Orbital Cyst: A Kinshasa Case Report

An early developmental lack of the optic vesicle can result in congenital anophthalmia, defined as a complete absence of the eye, which can be distinguished from congenital microphthalmos, where ocular rudiments are present. Here, a rare pediatric case of congenital clinical anophthalmos with orbital cyst in the left orbit is reported. The patient was a 14-month-old girl with no other congenital defects who underwent surgical and prothetic management in St. Josephs Hospital Kinshasa, Democratic Republic of the Congo (DRC). Surgery was carried out under general anesthesia. The cyst was punctured and its wall fully excised. Near the orbital apex pigmented elements representing iris, ciliary body, and choroidal or retinal remnants were found. The specimens were fixed in formalin for histological examination. Surgical cyst removal including socket deepening for an artificial eye was performed. Postoperative wound healing was uneventful and a satisfactory cosmetic outcome was achieved in all follow-up examinations. Histological examination revealed rudimentary ocular structures similar to degenerated lens tissue with a typical, PAS-positive capsule. Additionally, pigmented epithelial structures, which seem to be of ciliary body, iris, and choroidal or retinal-type epithelium origin, could be detected, prompting the final diagnosis, microphthalmia with dominant cyst formation.