Cataract Surgery in Patients with Keratoconus: Pearls and Pitfalls.

BACKGROUND: Keratoconus (KC) is a common ectatic disorder resulting in progressive corneal thinning and irregular astigmatism. It has been observed that patients affected by KC are more likely to develop lens opacities earlier compared to non-keratoconic patients. OBJECTIVE: Intraocular lens (IOL) selection and refractive outcome prediction are among a number of factors that can make cataract surgery in keratoconic patients challenging. Accurate biometry is often difficult to obtain due to unreliable K measurements and lack of dedicated biometric formulae. The use of toric IOLs has also been investigated. CONCLUSIONS: Determining the stage of KC, pre-operative patient counselling and the preferred method of refractive correction are all crucial to obtain successful postoperative outcomes and good patient satisfaction. The use of toric IOLs can achieve good results only in selected low-grade keratoconic eyes.

Dark Adaptation in Patients with Primary Open-Angle Glaucoma, Pseudoexfoliation Glaucoma and Childhood Glaucoma.

Purpose To investigate the state of dark adaptation and macular blood flow in different forms of glaucoma. Methods Eighteen eyes of 18 patients with primary open-angle glaucoma, 14 eyes of 14 patients with pseudoexfoliation glaucoma, and 10 eyes of 10 patients with childhood glaucoma (CG) were examined by means of dark adaptometry, scanning-laser retinal flowmetry, and retinal tomography. Results All glaucomatous eyes had comparable optic disc excavation (one-way ANOVA, p = 0.138). Eyes with CG had significantly lower best-corrected visual acuity than the other groups (Tukey, all p < 0.0001). Macular perfusion was comparable in all three groups (one - way ANOVA, p = 0.08). The delay in rod-cone break time in the CG group was significantly higher than in the other groups (Tukey, all p < 0.0001). The scotopic sensitivity threshold in the CG group was significantly greater than in the other groups (Tukey, all p < 0.01). Conclusion This underlying dysfunction of dark adaptation may contribute, at least to some extent, to the decreased visual perception observed in patients with CG.

Corneal sensitivity and morphology of the corneal subbasal nerve plexus in primary congenital glaucoma.

BACKGROUND: To quantify the corneal subbasal nerve density and the total number of nerve fibers in primary congenital glaucoma (PCG) and to evaluate their impact on corneal sensitivity. METHODS: Forty eyes of 26 PCG patients were compared with 40 eyes randomly selected from 40 non-glaucoma patients who populated the control group. Central corneal sensitivity (CCS) was assessed by means of Cochet-Bonnet esthesiometry. The mean subbasal nerve density and the total number of nerve fibers were quantified by laser-scanning confocal microscopy. Normality of data was assessed by Kolmogorov-Smirnov testing. Differences in parameters were assessed with Student's t-test, while correlations with CSS were assessed with Pearson's correlation. RESULTS: Significant differences were identified in the mean subbasal nerve density (2108 ± 692 µm in PCG, 2642 ± 484 µm in controls, P = 0.003) and in the total number of nerve fibers (12.3 ± 4.2 in PCG, 15.4 ± 3.1 in controls, P = 0.02). Both groups presented comparable mean CCS and tortuosity. Both groups presented strong correlations between CCS and mean nerve density (r = 0.57 in PCG, r = 0.67 in controls, all P < 0.05), and between CCS and total number of nerve fibers (r = 0.55 in PCG, r = 0.56 in controls, all P < 0.05). CONCLUSION: PCG exerts significant changes in both the mean subbasal nerve density and the total number of nerve fibers. However, these changes do not appear to affect central corneal sensitivity.

[Treatment of severe recurrent symblepharopterygium: combined ipsilateral autologous limbus and homologous amniotic membrane transplantation]. / Behandlung des schweren rezidivierenden Pterygiums mit Symblepharonbildung: Kombinierte ipsilaterale autologe Limbus- und homologe Amnionmembrantransplantation.

BACKGROUND: This retrospective study reports on four patients with severe recurrent symblepharopterygium formation and extensive subconjunctival scarring who were treated with a novel surgical technique combining free limbal autografting and amniotic membrane transplantation. PATIENTS AND METHODS: The surgical technique included symblepharolysis, meticulous removal of subconjunctival scar tissue, ipsilateral free limbal autograft and homologous amniotic membrane transplantation. RESULTS: There were no intraoperative or postoperative adverse events and three patients had no manifestation of recurrence of pterygium, symblepharon or diplopia during a mean follow-up period of 172 ± 18 weeks (39 ± 4 months) postoperatively. Only one patient had persistent symblepharon and experienced a recurrence of pterygium approximately 40 weeks (9 months) after surgery. CONCLUSION: The results suggest that ipsilateral autologous limbal and homologous amniotic membrane transplantation can be an effective therapeutic approach in the treatment of recurrent pterygium with symblepharon formation.

[New aspects on biomechanics of the cornea in keratoconus]. / Neues zur Biomechanik der Kornea beim Keratokonus.

Keratoconus is a bilateral, progressive, non-inflammatory corneal degeneration characterized by a conical protrusion of the cornea which leads to marked corneal thinning thereby inducing severe visual impairment due to increasingly irregular astigmatism. Current corneal imaging technology provides an accurate anatomical and topographical analysis of the cornea which is the 'gold standard for the diagnosis of keratoconus and preoperative screening in refractive surgery. Until recently evaluation of corneal biomechanics was feasible only in vitro as the technology required for in vivo analysis was not available. However, in recent years methods have been developed which enable an accurate in vivo analysis of corneal biomechanics thereby enhancing the early detection of keratoconus and improving the safety profile of corneal refractive procedures.

Dysfunctional uveoscleral pathway in a rat model of congenital glaucoma.

UNLABELLED: The purpose of the study was to investigate the presence of the uveoscleral pathway in the normotensive rat (NR) and in a rat model of congenital glaucoma (CGR). We injected the fluorescent tracer 70-kDa dextran rhodamine B in the anterior chamber of four NRs and four CGRs. At 10 and 60 minutes after injection, rats were euthanized by CO2 inhalation and eyes were enucleated. Cryosections were prepared and analyzed using fluorescent microscopy. Hematoxylin-eosin staining and electron microscopy of the anterior chamber angle (ACA) were performed. At 10 minutes after injection, fluorescent tracer was detected in the iris root and ciliary processes of NRs and CGRs. At 60 minutes, NRs showed prominent signal in the suprachoroidal, whereas, in the CGRs, tracer was barely detectable. Histology of the anterior chamber revealed the presence of an open ACA and electron microscopy confirmed the normal structure of the ciliary body in CGRs. CONCLUSIONS: Our results document the presence of an uveoscleral pathway in the normotensive rat. The rat model of congenital glaucoma shows severe impairment of the uveoscleral pathway, suggesting that alterations of the uveoscleral outflow might play a role in the pathogenesis of CG.

[Testosterone reduces the expression of keratinization-promoting genes in murine Meibomian glands]. / Reduzierung von Testosteron durch Expression Keratinisierung-fördernder Gene in der Meibom-Drüse der Maus.

BACKGROUND: Extensive keratinization appears to play a major role in the dysfunction of the Meibomian gland. This article presents the potential impact of androgens on limiting keratinization in this tissue, thus, contributing to normal Meibomian gland function and a healthy ocular surface. MATERIALS AND METHODS: Orchidectomized mice were systemically treated with either testosterone or placebo for 2 weeks. The mRNA was then extracted from the Meibomian glands and differential gene expression was investigated by microarray hybridization and evaluation with GeneSifter software as well as gene ontology information from the Gene Ontology (GO) Consortium. RESULTS: By z-score calculations, keratinization was the most significantly gene ontology term influenced by testosterone based on down-regulated genes in the mouse Meibomian gland. In particular, under the influence of testosterone the genes coding for small proline-rich protein (Sprr) 2a, Sprr 2b, Sprr 3, keratins 6a and 17 and periplakin were significantly down-regulated, while Sprr 1a and Sprr 2f were significantly up-regulated. CONCLUSIONS: Testosterone down-regulates the expression of genes promoting keratinization in the Meibomian gland. This may help to prevent Meibomian gland dysfunction by limiting excessive keratinization of this tissue and the adjacent lid margins. The findings elucidate, at least in part, the beneficial impact of androgens on Meibomian gland function and thus on th e health of the ocular surface.

[Delayed course of Acanthamoeba keratitis]. / Protrahierter Verlauf einer Akanthamöbenkeratitis.

A 35-year-old male presented with corneal ulceration on the left eye with a history of treatment over several months. At the first visit in our department we saw an elliptically shaped ulcerative stromal keratitis with circular peripheral neovascularization. There was organized hypopyon with hyphemia. The best corrected visual acuity (BCVA) was light perception. The patient had used contact lenses for many years. Under the suspicion of herpetic keratitis due to a positive "dendrite" the patient had undergone antiviral therapy for 6 months in a different department. Our diagnosis was Acanthamoeba keratitis. We performed penetrating excimer laser keratoplasty-à-chaud (8.0 × 7.0 mm/8.1 × 7.1 mm) with simultaneous cryotherapy of the mid-peripheral cornea. The topical therapy was polyhexamethylene biguanide, propamidine isoethionate, neomycin and steroids in intervals. A repeat penetrating excimer laser keratoplasty (8.5 × 7.5 mm/8.6 × 7.6 mm) with simultaneous amniotic membrane patch and lateral tarsorrhaphy was performed 2 months later due to melting of the graft with positive Seidel test. After successful surgery of the mature cataract the BCVA was 20/25. In a patient with a positive contact lens history acanthamoeba keratitis should always be considered as a differential diagnosis to herpes simplex keratitis in the early course of the disease.

[Ping-pong transmission of herpes simplex virus 1 following corneal transplantation]. / Ping-Pong-Transmission von Herpes-simplex-Virus 1 nach Hornhauttransplantation.

BACKGROUND: Primary corneal graft failure (PCGF) after penetrating keratoplasty (PKP) despite good endothelial cell count of the transplant in organ culture rarely occurs in young patients. A herpes simplex virus type I (HSV-1) infection (transmission through the donor or reactivation by the patient) can lead to PCGF. METHODS: We report on a 43-year-old man with pellucid marginal corneal degeneration and neurodermitis, who was underwent penetrating keratoplasty (PKP) on the left eye after acute corneal hydrops in both eyes. A repeat keratoplasty (re-PKP) had to be performed 15 days after the first PKP due to a primary graft failure. A re-re-PKP with simultaneous amniotic membrane transplantation (as a patch) and partial lateral tarsorrhaphy became necessary 4 months after the re-PKP due to melting on the edge of the graft with persistent epithelial defects. RESULTS: After intensive cooperation between ophthalmologists and pathologists the histopathological findings showed keratocytes which reacted immunohistochemically positive for HSV-1 antigens in the deep corneal stroma of both corneal grafts. The excised own cornea of the patient was histopathologically negative but the DNA-PCR for HSV-1 was weakly positive. After adequate topical and systemic antiviral therapy the third graft has remained clear for 12 months. CONCLUSION: In cases of PCGF after normal risk corneal transplantation the possibility of HSV infection should always be considered. After confirmation of the diagnosis with the help of the immunohistochemical tests and/or PCR, an adequate treatment with antiviral medication (acyclovir tablets 2 × 400 mg for more than 1 year) should be administered to the patient after repeat PKP.

[Acute unilateral loss of vision in a 38-year-old male patient]. / Akute einseitige Visusminderung bei einem 38-jährigen Patienten.

Although Valsalva retinopathy is a rare condition, it should be considered in the differential diagnosis of an acute macular hemorrhage in an otherwise healthy young patient. In most cases the patient presents with sudden, painless visual deterioration and a central scotoma. It is essential to immediately acquire a medical history because patients have typically undertaken strenuous physical activity in the recent past.

[Salzmann's nodular degeneration on a corneal graft 20 years after penetrating keratoplasty for keratoconus]. / Salzmann'sche noduläre Degeneration 20 Jahre nach perforierender Keratoplastik bei Keratokonus.

INTRODUCTION: We report a unique case of a young patient who underwent penetrating keratoplasty for keratoconus 20 years previously and presented in our department with visual deterioration due to Salzmann's nodular degeneration (SND) on the corneal graft, induced probably by underlying recurrent herpetic (HSV) keratitis. The patient was treated with phototherapeutic keratectomy (PTK) and despite the low endothelial density of the corneal graft, visual acuity was sufficiently restored. CONCLUSION: Treatment with PTK is a promising therapeutic option in SND to avoid repeat penetrating keratoplasty, even if the prognosis for the corneal graft is endangered by several risk factors (age of the graft, low endothelial density, subclinical recurrent HSV infection).