[Alterations in intraocular pressure and the CorVis parameters after LASIK]. / Änderung des Augeninnendrucks und der CorVis-Parameter nach LASIK.

INTRODUCTION: The reduction of corneal thickness following laser-assisted in-situ keratomileusis (LASIK) requires a correction of intraocular pressure (IOP) measurements. The corneal visualization Scheimpflug technology (CorVis ST, Oculus, Wetzlar, Germany) not only measures the IOP and central corneal thickness (CCT) but also determines 10 additional corneal parameters, such as the time to first and second applanation and velocity. Besides CCT we compared various corneal parameters before and after LASIK in order to detect possible correlations and to correct IOP measurements. METHODS: Measurements with CorVis ST were made before and after LASIK in 45 myopic patients (45 left eyes). We compared the IOP and CorVis ST parameters using a paired t­test before and after LASIK and corrected for possible correlations in a multifactorial linear model. Finally, we correlated the changes in IOP to changes in biomechanical parameters. RESULTS: We observed a direct correlation between the IOP measurements and the corneal thickness. The IOP was underestimated by 0.039 mm Hg per micrometer in reduction of corneal thickness. The multifactorial linear model showed a correlation of IOP change to A2 velocity and the radius of applanation. CONCLUSION: Surgical thinning of the central cornea via LASIK demonstrated a direct correlation between corneal thickness and IOP measurements using the CorVis ST technique. Postoperative changes of the A2 velocity and the applanation radius also had a statistically significant influence on post-LASIK IOP measurements. Our findings could be useful to obtain more precise post-LASIK IOP measurements.

[Intraocular Inflammation: Autoimmune or Infectious?]. / Intraokulare Entzündung: autoimmun oder infektiös?

Presentation of 3 cases of intraocular inflammation: 1. 47-year old female patient with severe necrotising scleritis and uveitis with underlying granulomatous polyangiitis (formerly known as Wegener granulomatosis, in honour of the German pathologist Friedrich Wegener), known for 10 years. 2. 48-year old male patient with longstanding bilateral uveitis and granulomatous polyangiitis for 2 years. In the histopathological examination of the enucleation specimen, a retrolental tumour turned out to be a granuloma. 3. 57-year old male patient in status post renal transplantation with intraocular cellular infiltration suspicious for lymphoma, which surprisingly proved to be Toxoplasma gondii-associated uveitis. The clinical course and characteristic histological signs and therapeutic options are discussed.

Outcomes of Descemet membrane endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and penetrating keratoplasty from a single centre study.

PURPOSE: According to some pioneer surgeons, lamellar endothelial keratoplasty techniques (EK), including Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK), yield excellent clinical results. However, there is a lack of studies with high levels of evidence and results of large national keratoplasty registers are contradictory. Therefore, two large cohorts of DMEK and DSAEK procedures are compared to a cohort of penetrating keratoplasty (PK). METHODS: The study reports 868 keratoplasty procedures at a single centre (694 eyes with Fuchs endothelial dystrophy (FED) and 174 with bullous keratopathy (BK)). Patients underwent DMEK (450 eyes), DSAEK (89 eyes), or PK (329 eyes). Postoperative visual acuity, endothelial cell density (ECD), rate of regrafting, and rejections were recorded. RESULTS: Visual acuity recovers faster and to a greater extent in EK compared to PK. DMEK performs better than DSAEK. ECD drops faster initially for EK compared to PK. In EK the rate of regrafting is higher than in PK (7 % in DMEK, 20 % in DSAEK and 2 % in PK in FED). The rejection rate is lowest following DMEK (7 % after DMEK, 21 % after DSAEK and 18 % after PK in FED). CONCLUSIONS: In contrast to recent reports from national keratoplasty registers, the overall clinical outcome of EK in FED and BK is superior to PK. Including ocular comorbidities and learning curves, these data reflect a realistic setting for comparing the different keratoplasty techniques. Corneal surgeons may be encouraged to preferentially use DMEK in FED and BK.

Prolonged organ culture reduces the incidence of endothelial immune reactions.

PURPOSE The number of antigen-presenting cells decreases during organ culture of corneoscleral discs. This might result in a decrease of immune reactions with increasing duration of organ culture. To investigate this hypothesis, we performed a retrospective analysis of all penetrating keratoplasties that were consecutively performed over the last 5 years.PATIENTS AND METHODS All cases of penetrating keratoplasties (n=1006) were divided into two groups, with the division made at the median of the storage time (21 days). These two groups were compared by a Cox proportional hazards survival model regarding the incidence of endothelial immune reactions, clear graft survival, and chronic endothelial cell loss following penetrating keratoplasty considering patient's age, donor's age, and risk situation as co-variates.RESULTS We observed statistically significantly fewer endothelial immune reactions (20.1% (95% confidence interval 15.5-24.5%) after 2 years) in the group with a storage time of more than 21 days compared with the group with a storage time of <21 days (26.5% (95% confidence interval 21.6-31.2%) after 2 years). However, the duration of organ culture did not have a statistically significant effect on clear graft survival or chronic endothelial cell loss.CONCLUSION Our results demonstrate that an increased duration of organ culture leads to a lower incidence of endothelial immune reactions following penetrating keratoplasty. However, we do not recommend increased storage times in general as overall graft survival did not improve. The reason for this apparent paradox may be that the endothelial cell count decreases during storage time.

[Intraocular Lens Opacification Following Posterior Lamellar Keratoplasty]. / Kunstlinsentrübungen nach hinterer lamellärer Keratoplastik.

BACKGROUND: The opacification of an artificial intraocular lens is a rare but serious complication following cataract surgery as an exchange of the intraocular lens can become necessary. At our eye center we observed single cases of IOL opacifications following complicated posterior lamellar keratoplasty (Descemet stripping automated endothelial keratoplasty = DSAEK or Descemet membrane endothelial keratoplasty = DMEK). Therefore, we performed a retrospective analysis of all our digital charts regarding the incidence of this serious complication with respect to posterior lamellar keratoplasty, penetrating keratoplasty or sole cataract extraction. METHODS: We searched our digital patient database from 2003 to 2015 using the following headings: intraocular lens, artificial lens or IOL and opacification or calcification and selected only those patients who had undergone either DSAEK, DMEK, penetrating keratoplasty or sole cataract surgery (n = 19,565). RESULTS: In total we found five IOL opacifications out of 153 DSAEK and two out of 450 DMEK cases, respectively. Five of these seven cases had a complicated clinical course with repeated rebubbling or additional intraocular surgery (i.e., repeat DSAEK or DMEK or secondary penetrating keratoplasty). There were no documented IOL opacifications following penetrating keratoplasty or sole cataract extraction. In two cases intraocular lens exchange became necessary. All opacifications showed similar clinical appearance in form of small granular deposits on the surface of the intraocular lens. Almost all implanted lenses were made from hydrophilic acrylate. DISCUSSION: In total we found seven cases of intraocular lens opacification that have only been observed following DSAEK or DMEK. According to reports from the literature these opacifications are superficial calicifications of the hydrophilic lenses. As five of the seven cases had a complicated clinical course, the repeated air contact of the lens could be one major factor in inducing the calcification. Besides the air contact a breakdown of the blood-aqueous barrier could also play a role in the induction of calcium phosphate crystallisation on the intraocular lens. The risk of this serious complication in mainly hydrophilic intraocular lenses with respect to posterior lamellar keratoplasty should be kept in mind for the selection of the type of intraocular lens in patients with endothelial diseases or in patients undergoing combined cataract extraction and DSAEK/DMEK.

Visual outcome and histological findings following femtosecond laser-assisted versus microkeratome-assisted DSAEK.

BACKGROUND: The aim of this study was to compare the visual outcome of femtosecond laser-assisted Descemet stripping automated endothelial keratoplasty (DSAEK) to microkeratome-assisted DSAEK as well as to contrast precut versus surgeon-cut grafts. Histologic characterization of failed DSAEK grafts was performed in order to correlate ultrastructural changes with graft failures. METHODS: In this case control study, 47 cases of DSAEK were investigated in terms of visual acuity, keratometric astigmatism, spherical equivalent, endothelial cell count, and postoperative complications. We formed three groups: the femtosecondlaser-assisted DSAEK with precut grafts, the microkeratome-assisted DSAEK with precut and with surgeon-cut grafts. Mean follow-up was 6 months. In the case of graft failure, penetrating keratoplasty was performed, and the excised corneal buttons were investigated by light and electron microscopy. RESULTS: Microkeratome-assisted DSAEK lead to better visual outcome than femtosecond laser-assisted DSAEK. Keratometric astigmatism, spherical equivalent and endothelial cell count did not differ significantly between both methods. Precut and surgeon-cut grafts in microkeratome-assisted DSAEK did not show any significant difference regarding all upraised parameters. No definite histological correlate for graft failure following femtosecond laser-assisted DSAEK was found. CONCLUSIONS: Femtosecond laser-assisted DSAEK is not the method of choice, and needs further technical improvement. However, failed femtosecondlaser-assisted DSAEK grafts did not show significant histological changes related to the technique to explain reduced visual acuity. In microkeratome-assisted DSAEK, the preparation time point of the graft does not seem to influence the visual and optical outcome.

[Perspectives of posterior lamellar keratoplasty. In search of the perfect lamella]. / Perspektiven der hinteren lamellären Keratoplastik. Auf der Suche nach der perfekten Lamelle.

Corneal endothelial diseases, such as Fuchs' endothelial dystrophy and bullous keratopathy represent the most common indications for keratoplasty. Replacement of the entire cornea by penetrating keratoplasty has been the gold standard in treating corneal endothelial diseases for many decades. However, recently new and innovative surgical techniques for selective endothelial replacement have been developed. These are Descemet stripping (automated) endothelial keratoplasty (DS(A)EK), Descemet membrane endothelial keratoplasty (DMEK) and hybrid techniques of both. The distinct advantages and drawbacks of lamellar and penetrating techniques reveal the need of comparative studies to find out which method is suitable for which patient, particularly with regard to long-term visual rehabilitation.

[Chronic dacryocystitis 24 years after dacryocystorhinostomy?]. / Chronische Dakryozystitis 24 Jahre nach Dakryozystorhinostomie? Diagnose: Extraorbital gelegenes Hämangioperizytom (solitärer fibröser Tumor bzw. SFT nach WHO).

A 50-year-old woman suffered from recurrent swelling and inflammation in the region of the medial portion of the lower eyelid 24 years after right-sided dacryocystorhinostomy. The tumor was removed in two stages under histological control of the excision margins. No evidence for malignancy was found. During the follow-up period of 4 years the patient remained recurrence free and without complaints. The diagnosis reached was an extraorbital hemangiopericytoma.