Wolfgang Philipp

Histological and immunohistochemical findings after laser in situ keratomileusis in human corneas

Purpose: To describe histopathological and immunohistochemical findings in human corneas after myopic laser in situ keratomileusis (LASIK) followed by iatrogenic keratectasia and after hyperopic LASIK. Setting: Department of Ophthalmology, University of Innsbruck, Innsbruck, Austria. Methods: Clinical, histological, and immunohistochemical investigations were performed of 1 human cornea with iatrogenic keratectasia following myopic LASIK and 1 human cornea with irregular astigmatism and central scar formation after hyperopic LASIK. Corneal buttons were obtained during penetrating keratoplasty in both patients. Results: Histopathological examination showed thinning of the central stroma with a posterior residual thickness of 190 &mgr;m in the patient with iatrogenic keratectasia after myopic LASIK and significant midperipheral thinning in the patient who had hyperopic LASIK. However, this characteristic ablation profile of the stroma after hyperopic LASIK was partially mitigated and compensated by the epithelium, which was significantly thinned in the center and markedly thickened in the midperiphery. Traces of wound healing with minimal scar tissue were present at the flap margin after myopic and hyperopic LASIK. In a few sections of the cornea with keratectasia after myopia LASIK, only a few collagen lamellae were visible crossing between the posterior residual stroma and the superficial flap. Immunohistochemical examination revealed minimally increased staining of dermatan sulfate proteoglycan within the stroma adjacent to the interface of the microkeratome incision. Increased staining of hepatocyte growth factor was found on keratocytes/fibroblasts at the flap margin in both corneas. Conclusions: The wound‐healing response is generally poor after LASIK, which may result in significant weakening of the tensile strength of the cornea after myopic LASIK, probably due to biomechanically ineffective superficial lamella. After LASIK in patients with high hyperopia, compensatory epithelial thickening in the annular midperipheral ablation zone might be partly responsible for regression.

The effect of streptozotocin-induced diabetes mellitus on substance P and calcitonin gene-related peptide expression in the rat trigeminal ganglion

Substance P (SP) and calcitonin gene-related peptide (CGRP) constitute the main sensory peptides in the trigeminal ganglion (TG). The objective of this study was to characterize peptidergic changes in the streptozotocin-induced diabetes mellitus rat model both quantitatively and qualitatively. Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (65 mg/kg) and the levels of SP and CGRP were measured by means of radioimmunoassay (RIA) in a time-dependent manner. Peptide immunoreactivities were characterized by high pressure liquid chromatography (HPLC). The expression of both neuropeptides was examined 5 weeks after streptozotocin injection using in situ hybridization with 35S-labelled oligonucleotides. Saline-injected rats served as controls. SP was significantly decreased in the diabetic rat TG, i.e. , a 44.6% (+/-10.9) decrease after 1 week, 40.2% (+/-11.8) after 3 weeks and 72.3% (+/-14.6) after 5 weeks. CGRP was decreased only after 5 weeks (19.6% decrease +/-3.9), whereas at later stages, both peptide levels returned to normal values. HPLC revealed one major peak coeluting with the synthetic peptides. By using in situ hybridization, a significantly increased signal of both peptide-encoding mRNAs was found (43.8%), which seems to act to restore a diabetes-associated depletion of neuropeptides in the diabetic rat TG. The decreased SP- and CGRP levels in the diabetic rat TG reflect a diabetes-associated deficit which may be clinically relevant. Diabetes mellitus is associated with a variety of ocular complications, even corneal complications, including decreased corneal sensitivity, which in many ways resemble those after interruption of the normal trophic innervation of the eye. Our results point to reduced availability of neuropeptides for corneal innervation and may thus support the idea of a partial loss of trophic influences from the trigeminal nerve in diabetics.

Altered lectin binding sites in keratoconus corneas

We investigated the glycoconjugates in frozen sections of keratoconus corneas, using a panel of 12 biotin- or fluorescein isothiocyanate-labeled lectins. No differences between the lectin binding sites of the epithelium, endothelium and Descemets membrane of normal and keratoconus corneas could be observed. However, in contrast to normal corneas, intense staining with peanut agglutinin (PNA) could be detected at breaks in Bowmans layer, in scar tissue and in the adjacent stroma. Furthermore, in the majority of cases binding sites for Phaseolus vulgaris erythroagglutinin (PHA-E) and increased staining with Ricinus communis agglutinin I (RCA-I) and Lens culinaris agglutinin (LCA) could also be detected in ruptures in Bowmans layer and in scar tissue. These data suggest that the scarred regions of the anterior stroma in keratoconus corneas may contain oligosaccharides with terminal D-galactose (beta 1-3)-D-N-acetylgalactosamine disaccharides (recognized by PNA), increased amounts of glycoconjugates with terminal beta-galactose residues (recognized by RCA-I), increased amounts of glycoconjugates with glucose/mannose residues (recognized by LCA), and finally, biantennary complex-type glycopeptides containing two outer galactose residues and a residue of N-acetylglucosamine (recognized by PHA-E). Since corneal scars due to causes other than keratoconus revealed lectin binding sites (particularly for PNA and to a lesser extent also for PHA-E, LCA and RCA-I) similar to those seen in scar tissue of keratoconus corneas, we conclude that it is mainly scar formation that may be responsible for the altered lectin binding sites in keratoconus.

Leukozyten-Adhäsionsmoleküle bei chronisch-entzündlichen Erkrankungen der Hornhaut

Using immunohistochemical techniques, we investigated the expression of leukocyte adhesion molecules – intercellular adhesion molecule-1 (ICAM-1), E-selectin (endothelial leukocyte adhesion molecule-1), and vascular cell adhesion molecule-1 (VCAM-1) – in various chronic inflammatory corneal diseases of different etiology. ICAM-1 was focally expressed on epithelial cells and showed an increased expression, on keratocytes, corneal endothelial cells, and vascular endothelial cells. E-selectin was present on vascular endothelial cells of several corneas, while VCAM-1 was found particularly on macrophages and only sporadically on vascular endothelial cells. Our results suggest that ICAM-1, E-selectin, and VCAM-1 may be involved in the pathogenesis of various chronic inflammatory corneal diseases, particularly in the selective recruitment of different leukocyte populations.

Retinal phakomata associated with cerebral astrocytoma: an incomplete form of Bourneville-Pringle disease?

We report on a 21-year-old, male patient with unilateral retinal phakomata associated with histologically proved cerebral astrocytoma. The patient had presented with bilateral loss of vision and a left-sided hemiparesis. Ophthalmoscopy showed bilateral optic nerve atrophy, multiple punched-out areas of depigmentation and astrocytic hamartomata in the right eye. Despite the absence of classic signs of Bourneville-Pringle disease such as adenoma sebaceum, epilepsy and mental retardation, a strongly presumptive diagnosis of tuberous sclerosis could be made. This unusual case demonstrates that retinal phakomata can be the solely visible manifestation of Bourneville-Pringle disease.

Pars-plana-Lensektomie bei kongenitaler Katarakt, klinische Langzeitergebnisse

ZusammenfassungHintergrundBei der Operation der kindlichen Katarakt muss einerseits die hohe Nachstarrate, andererseits das noch nicht abgeschlossene Längenwachstum des kindlichen Auges berücksichtigt werden, das bei einer zu frühen Linsenimplantation zu einem starken myopen Shift führen kann. Aus diesem Grund wird in der Regel bei Kindern unter 1,5–2 Jahren generell keine Kunstlinse implantiert und der postoperative Refraktionsausgleich erfolgt zunächst am besten mit einer Kontaktlinse während bei älteren Kindern immer mehr dazu übergegangen wird primär eine Hinterkammerlinse zu implantieren. Die Operation ist sowohl über einen limbusnahen Zugang, als auch über die Pars-plana möglich. Die vorliegende Arbeit analysiert unsere Erfahrungen mit letztgenannter Technik und die daraus folgenden Langzeitergebnisse bezüglich Nachstarrate, Visus, Refraktionsentwicklung und Binokularfunktion.Patienten und MethodikIm Zeitraum von 1994 bis 2002 führten wir an 26 Augen von 15 Patienten eine Pars-plana-Lensektomie mit einer vorderen und hinteren Kapsulotomie sowie eine vordere Vitrektomie durch. Bei 11 Patienten bestand eine bilaterale Katarakt (22 Augen, durchschnittliches Alter bei OP 2,3 Monate), bei 4 Patienten eine unilaterale Katarakt (4 Augen, Alter zwischen 1 Monat und 3,5 Jahren). Postoperativ erfolgte der Aphakieausgleich mittels Kontaktlinsen oder Brillen sowie eine orthoptische Nachbehandlung an der Sehschule. Bei 7 Augen wurde im Alter zwischen 3,5 und 6 Jahren eine Sekundärimplantation einer Hinterkammerlinse durchgeführt.ResultateBei allen Augen konnten durch die Operation klare optische Medien erreicht werden. Der durchschnittliche Visus cc. betrug nach bilateralen Katarakten mit 4a 0,3 und mit 7a 0,5 (Range 0,16–0,8). Bei 4 Augen trat zwischen 1,5 und 3,5 Monaten postoperativ zentral ein regeneratorischer Nachstar auf, der operativ entfernt werden musste. Ansonsten wurden bis auf einen Fall eines Sekundärglaukoms keine Komplikationen dokumentiert. Bei 2 Patienten war Simultansehen, bei 2 Fusion und bei einem Stereosehen nachweisbar. Bei 3 Kindern kam es zu keiner Binokularfunktion, die restlichen waren diesbezüglich auf Grund des Alters nicht beurteilbar. Nach unilateraler Katarakt konnte ein durchschnittlicher Visus cc. von 0,1 am operierten Auge erreicht werden. Eine Binokularfunktion war nur bei einem Patienten nachweisbar. Die Refraktion der aphaken Augen verringerte sich durchschnittlich von +25 Dpt. mit wenigen Monaten auf +20 Dpt. mit la, auf + 17 Dpt. mit 3a und stabilisierte sich schließlich mit ca. 4–7 Jahren bei +16 bis +17 Dpt.SchlussfolgerungDie Pars-plana-Lensektomie erwies sich in unseren Händen als eine sichere und komplikationsarme Methode der Kataraktoperation in den ersten beiden Lebensjahren, in denen die Implantation einer Linse wegen des noch nicht abgeschlossenen Wachstums des Auges später zu einem massiven myopen Shift führen kann. Um möglichst eine Nachstarbildung besonders bei Kindern in diesem Lebensalter zu verhindern, kann mit dieser Technik relativ einfach zugleich eine hintere Kapsulotomie und vordere Vitrektomie durchgeführt werden. Später kann nach weitgehend abgeschlossenem Längenwachstum des Auges sekundär eine Hinterkammerlinse mit einem in der Regel guten refraktiven Ergebnis implantiert werden.SummaryPurposeSeveral techniques of cataract surgery in young children must take into account the high rate of posterior capsule opacification (PCO) on one hand, and the incomplete growth of the eye in infants on the other hand which may result in a high myopic shift if lens implantation is performed too early. As a consequence, generally no lens is implanted in children younger than 1.5–2 years of age, and postoperative aphakia is corrected by contact lenses or spectacle glasses. In contrast, primary posterior chamber lens (PCIOL) implantation is the method of choice in older children. Surgery may be performed via a limbal or pars plana approach. The present paper deals with our experience and long-term results of pars plana lensectomy in infants particularly regarding best corrected visual acuity (BCVA), PCO rate, evolution of refractive error changes and development of binocular functions.Patients and methodsBetween 1994 and 2002 pars plana lensectomy with anterior and posterior capsulotomy and anterior vitrectomy was performed in 11 children (mean age 2.3 months at time of surgery) with bilateral congenital cataracts (22 eyes) and in 4 patients between 1 month and 3.5 years of age with unilateral cataracts. Correction of aphakia was performed with contact lenses or spectacle glasses and all patients underwent intensive orthoptic examinations postoperatively. In 7 eyes secondary PCIOL implantation was performed between 3.5 and 6 years of age.ResultsIn all eyes a clear visual axis could be achieved after surgery. Mean best corrected visual acuity increased from 0.3 at an age of 4 years to 0.5 (range 0.16–0.8) at 7 years. Elschnig pearl PCO which required surgical removement occurred in 4 eyes between 1.5 and 3.5 months postoperatively. Other complications with the exception of one case with secondary glaucoma were not observed. Binocular functions could be detected in 5 patients and were lacking in 3 children but could not be assessed in the remaining patients due to their low age. Patients with unilateral cataracts achieved mean BCVA of 0.1 after surgery. Binocular functions were detected only in one patient. Mean postoperative refraction of aphakic eyes decreased from +25 dpts at an age of few months to +20 dpts with 12 months, to +17 dpts with 3 years, and stabilized at +16 and +17 dpts between 4 to7 years of age.ConclusionsIn the present study we could show that pars plana lensectomy is a save and efficacious method of cataract surgery in children younger than 2 years of age, in whom primary PCIOL implantation would lead to a significant myopic shift due to the incomplete axial growth of the infant’s eye. With this technique lensectomy with anterior and posterior capsulotomy simultaneously with anterior vitrectomy may be performed relatively easily using the same small incision through the pars plana/pars plicata. Secondary PCIOL implantation — usually with good refractive results — may be taken into consideration later when the axial growth of the eye is completed.

Langerhans Cells in the Recipient Cornea as Prognostic Indicator in Corneal Transplantation

The aim of the present study was to investigate whether there is a correlation between the density of Langerhans cells (LC) in the recipient cornea (graft bed) and the incidence of immunologically caused graft failures.