[Influence of corneal biomechanical properties on myopic regression after laser in situ keratomileusis]. / Einfluss der kornealen Biomechanik auf die Myopieregression nach Laser-in-situ-Keratomileusis.

BACKGROUND: Laser in situ keratomileusis is a safe and accepted method for correcting myopia. The operational results in terms of accuracy as well as the subjective acceptance of patients for corrections to - 8 D are now considered to be promising (Seiler, Refraktive Chirurgie der Hornhaut, 2000); however, postoperative results show individual patient problems in long-term stability. It is believed that the preoperative condition of the cornea (e.g. thickness, biomechanical properties) could have an influence on postoperative problems such as myopic regression. METHOD: This study included a total of 46 eyes from 25 patients. At 3 months postoperatively, 15 patients (19 eyes) showed a SEQ of -0.50 D or more. Within this group, 11 patients (15 eyes) developed a regression (regression group) within the first 3 postoperative months. The remainder of the total group did not show any regression (stability group). The subjects of this study were on average 33 ± 8 years (stability group) and 31 ± 7 years old (regression group). The corneal thickness was tested and refractive error, visual acuity (BCVA/UCVA) and intraocular pressure was measured. In addition, the corneal hysteresis (CH) and corneal resistance factor (CRF) were determined. RESULTS: The mean preoperative spherical equivalent refraction was -3.14 D ± 1.41 D (SE) in the stability group and - 6.47 D ± 1.40 D (p = 0.001)in the regression group. Also, the postoperative spherical equivalents were statistically significant different (p < 0.05). In contrast, the mean preoperative corneal thickness showed no differences in both groups (p = 0.96) (stability group 563 ± 36 µm and regression group 563 ± 28 µm). CONCLUSIONS: The aim of the study to detect a possible causal relationship between myopia regression after LASIK and the biomechanical properties of the cornea and corneal thickness could not be clearly identified.

[Unilateral papilledema with contralateral loss of vision]. / Einseitiges Papillenödem und kontralateraler Visusverlust.

A 46-year-old woman presented with a 4-day history of headache, dizziness and blurred vision in the left eye and a 1-year history of neck pain. Fundoscopy revealed a pale optic disc in the left eye and a swollen optic disc in the right eye. Furthermore a bilateral anosmia was evident. Cranial magnetic resonance imaging (MRI) showed a mass in the anterior cranial fossa, which was classified as a WHO grade I endotheliomatous meningeoma. A Foster Kennedy syndrome was diagnosed.

[Scanning electron microscopic characteristics of lamellar keratotomies using the Femtec femtosecond laser and the Zyoptix XP microkeratome. A comparison of quality]. / Vergleich des Femtec Femtosekundenlasers und des Zyoptix XP Mikrokeratoms. Rasterelektronenmikroskopische Gegenüberstellung lamellärer Keratotomien.

OBJECTIVE: To demonstrate the qualities and compare the typical features of cut surfaces and cut edges created by the Femtec femtosecond laser and the Zyoptix XP microkeratome, using scanning electron microscope (SEM) pictures. METHODS: Lamellar keratotomies were performed using a femtosecond laser (40 kHz) or a microkeratome on freshly enucleated porcine eyes (n=16, eight each per technique). After special preparation, SEM images were taken to evaluate the qualities of the cut surfaces and cut edges. Therefore, special criteria were involved, including relief and homogeneity of the surface and sharpness of the cut edges. RESULTS: Surfaces created by microkeratome cuts were very homogenous. Concerning surface relief, nearly no irregularities occurred. Cut edges showed a flat, serrated course from the epithelial layer to the stroma of the cornea. The edges were sharp and easily visible. After preparation using the femtolaser, the surface showed many rips in the tissue, leading to irregularities. Nevertheless, the cut edges were very sharp and entered the corneal layer straight at 90 degrees . CONCLUSIONS: A comparison of the two systems shows that the microkeratome creates a more homogenous cut surface. The need for preparation after automated cutting with the femtosecond laser leads to irregularities on the cut surface. The cut edges of both systems tested here differ concerning their angles on entering the tissue. With regard to the sharpness of the cuts, the qualitative aspect is nearly similar, although the cut edges of the microkeratome are serrated. Because the microkeratome-cut edge has a flatter course, the wound area might be bigger. Cut edges with the steepness produced by the femtosecond laser could be an advantage for repositioning the flap after LASIK. If excimer laser ablation is performed later, the flap bed created by the femtosecond laser could be disadvantageous.

[Clinical course of a solitary retinal astrocytoma]. / Klinisch-zeitlicher Verlauf eines solitären retinalen Astrozytoms.

Retinal astrocytomas are benign tumors of the retina. Their localization can be solitary, multiple, or bilateral in both eyes. It is also known that they can be part of a phakomatosis syndrome (i.e., tuberous sclerosis or neurofibromatosis). Because retinal astrocytomas have a slow growth rate, yearly controls by an ophthalmologist with interdisciplinary consultation are adequate. Some uncommon cases have been reported in which the tumor has grown more aggressively. These tumors may require therapeutic interventions (e.g., vitreoretinal surgery, brachytherapy, photodynamic therapy, or cryotherapy).

[Unusual myopic fundus alteration]. / Ungewöhnliche myope Fundusveränderung.

A 44-year-old female patient reported a "black dot" which had been in front of the right eye for more than 4 days and which moved together with eye movements. The optical coherence tomography (OCT) image of the right macula showed large cystic cavities and thickening within the retinal pigment epithelium (RPE) near the fovea centralis as well as small bore cystic alterations, which indicated an event in the region of the choroid. Fluorescein angiography and indocyanine green angiography excluded choroidal neovascularization (CNV). The diagnosis revealed a broad superficial choroidal blood vessel mimicking a subretinal hemorrhage.

Retinal colour duplex scanning during LASIK-ring suction with different keratomes.

PURPOSE: The purpose was to measure the blood flow velocity during the suction phase of LASIK. SETTING: University Eye Hospital, Martin-Luther-University Halle-Wittenberg, Halle, Germany. METHODS: Papillary blood flow velocity was measured by colour Doppler sonography. Suction rings of four different manufacturers were applied in 30 healthy volunteers without eye diseases all of normal blood and eye pressure. The velocity of the blood flow in the central retinal artery was measured before, during and after suction. RESULTS: When Hansatome (Bausch & Lomb) and M2 (Moria) rings were used, no blood flow velocity was detected during suction in 90% of all cases. These rings were compared to the SKBM standard suction ring (Alcon) and the Krumeich non-IOP ring, in which no blood was present in only 56.67% (p < 0.05) and 10% (p < 0.001) of cases respectively. Moria, Alcon and Krumeich Lasitome rings performed equally well during the recovery phase compared with the original values. An exception is the Hansatome ring (Bausch & Lomb), with lower velocities when evaluated after 30 minutes (p < 0.01). CONCLUSIONS: During the ring suction phase of LASIK, the rings tested reduce velocity differently.

[Hazeformation (corneal scarring) after cross-linking therapy in keratoconus]. / Haze-Bildung nach Vernetzungstherapie bei Keratokonus.

The aim of cross-linking therapy is to prevent keratoconus progression and stabilize the present refractive situation. A 41-year-old man was treated with collagen cross-linking in one eye. Postoperatively there were a diffuse subepithelial opacification and a paracentral corneal thinning. This superficial scarring in the sense of a "haze" disappeared only gradually despite intensive therapy.

Pellucid marginal corneal degeneration: evaluation of the corneal surface and contact lens fitting.

AIM: To quantify corneal irregularities, to describe the fitting with contact lenses, and to answer the question whether or not contact lenses with a special back surface design could improve visual acuity in patients with pellucid marginal corneal degeneration (PMCD). METHODS: 13 eyes were fitted with contact lenses with a special back surface. Videokeratographic data were assessed. The patients were followed up for an average period of 22.2 months. Lens tolerance and corrected visual acuity were evaluated. RESULTS: The mean eccentricity did not exceed 0.7 in all patients. Either the superior or the inferior eccentricity, or both, were negative in all patients. Using Fourier analysis all PMCD subjects showed an increased irregular astigmatism of the anterior cornea. Using Zernike coefficients seven eyes (53.8%) had a higher order aberration root mean square error (HOA RMS error) out of the normal range. The visual acuity with contact lenses improved in all eyes with an average increase of 2.7 lines (maximum eight lines). No serious complications were observed. CONCLUSIONS: Quantitative evaluation of videokeratographic data may help to diagnose PMCD and to distinguish PMCD from other ectatic corneal diseases. Contact lenses with a special back surface design can improve visual acuity and lens tolerance.

[Molecular genetic analysis of the BIGH3 gene in lattice type I (Biber-Haab-Dimmer) and granular type II (Avellino) corneal dystrophy: is indirect mutation analysis for hot spots recommended?]. / Molekulargenetische Analyse des BIGH3-Gens bei gittriger Hornhautdystrophie Typ I (Biber-Haab-Dimmer) und bei bröckliger Hornhautdystrophie Typ II (Avellino): Erlauben Hot Spots einen indirekten Mutationsnachweis?

BACKGROUND: Mutations of the BIGH3 gene were delineated as the underlying gene defect for corneal dystrophy Lattice Type I (CDL1) and corneal dystrophy Avellino type (CDA) in families with different regional provenance. Missense mutations in exon 4 with single base pair substitution which result in amino acid alterations Arg124Cys (CDL1) and ARG124His are described as hot spots. We report on histopathological and molecular genetic investigations in 2 German families and a single patient with CDL1 and CDA. METHOD: In 3 affected family members and 1 unaffected family member and in one single patient with CDL1 and in 3 affected family members and 1 unaffected family member of a family with CDA mutation analysis in exon 4 of BIGH3 gene by direct sequencing of genomic DNA from peripheral blood was performed. Histopathological examination of corneal tissue of both index patients was performed after penetrating keratoplasty. RESULTS: We revealed a heterozygous single base pair substitution 417C-->T in family A and patient B (CDL1) and a heterozygous single base pair substitution 418G-->A in family C (CDA). In all index patient's diagnosis was confirmed by histopathological examination of corneal tissue. The sequencing results were confirmed by restriction digestion with HpyCH4V (NEB; CDL1) restriction endonuclease site and AvaII (NEB; CDA) restriction endonuclease site. The heterozygous 417C-->T transition in family A and patient B alters the amino acid sequence from Arg124Cys while the heterozygous 418G-->A transition in family C alters the amino acid sequence from Arg124His in the keratoepithelin. COMMENT: Codon 124 of the BIGH3 gene appears as a mutation hot spot also in German families with CDL1 and CDA. Indirect mutation analysis with restriction digestion is suggested as first step investigation in families with relevant corneal dystrophies. Direct sequencing of all exons is recommended as a second step if there are no results in restriction digestion.

[Lamellar keratoplasty. Back to the future?!]. / Lamelläre Keratoplastik. Zurück in die Zukunft?!

In 1840 Mühlbauer was the first to describe a technique for anterior lamellar keratoplasty (LKP). However, in the second half of the twentieth century penetrating keratoplasty (PKP) became the gold standard. Although it is associated with a higher risk for serious complications -- it is technically easier to perform and avoids wound healing reactions in the lamellar interface and thus resulting in better visual acuity. In view of the pathology, replacing all layers of the cornea including healthy parts can be considered therapeutic "overkill" for many corneal graft indications. Several innovative surgical techniques have recently been described which allow the lamellar dissection of recipient and donor cornea with good reproducibility in almost every desired depth. This now allows the recipient endothelium and Descemet's membrane to be selectively replaced or preserved and to avoid formation of an optical barrier in the lamellar interface in eyes undergoing lamellar keratoplasty for optical indications. The most important principal advantage of an anterior LKP -- to minimize the risk of an immune reaction in the graft -- is even more important in tectonic indications. From the large number of variations, the surgical technique, results, and problems with anterior and posterior LKP for optical indications as well as lamellar segment keratoplasty and epikeratoplasty for tectonic indications are discussed.

Contact lenses and special back surface design after penetrating keratoplasty to improve contact lens fit and visual outcome.

AIMS: To describe the fitting of patients with high or irregular astigmatism following penetrating keratoplasty with contact lenses and to answer the question whether or not contact lenses with special back surface design can improve visual acuity in complex cases after penetrating keratoplasty. METHODS: 28 eyes were included. They were fitted with contact lenses with a special back surface that was designed for optical rehabilitation after penetrating keratoplasty. Four different types of these lenses (tricurve, keratoconus, reverse, oblong) were used selectively depending on abnormal eccentricity determined by videokeratoscope. The patients were followed up for an average period of 15.5 months. Lens tolerance and corrected visual acuity were evaluated and compared with that corrected with spectacles. RESULTS: The visual acuity was significantly improved in nearly all eyes with an average increase of 3.6 lines (maximal nine lines) accompanied by good contact lens tolerance and satisfactory contact lens fit. No noticeable complications were observed. CONCLUSION: Contact lenses with special back surface design can improve visual results and lens tolerance, and minimise problems in contact lens fitting. This is in favour of contact lenses as an alternative to surgical procedures for correction of high or irregular astigmatism after penetrating keratoplasty. This procedure is recommended especially in cases of patients who decline further operative interventions.

[Ocular side-effects associated with amiodarone therapy]. / Okuläre Nebenwirkungen der Amiodaron-Therapie.

Amiodarone, one of the most effective anti-arrhythmic drugs, is also known for its ability to accumulate lipid-pharmakon complexes in the lysosomes of different tissues. In the eye the lysosomal storage leads to typical side-effects. Whorl-like epithelial, reversible corneal inclusions occur in about 70 to 100 % of the patients on amiodarone therapy. Tiny lens opacities without visual impairment have been reported in 50 % of patients who had been treated with amiodarone. At present the most severe complication of amiodarone is optic neuropathy with an incidence of 1.3 to 1.8 %. The optic neuropathy, as the rule, is only reversible approximately in (1/2) of the patients after discontinuing the drug. The fundoscopic picture of amiodarone neuropathy is similar to classic AION. Retinal involvement has also been reported; however, a relationship with amiodarone has not been proven yet.

Molecular genetic and ocular findings in patients with holt-oram syndrome.

PURPOSE: The autosomal dominant Holt-Oram syndrome (HOS) is characterized by upper limb and cardiac septal defects. Mutations of the TBX5 gene have been identified as the underlying gene defect in HOS. Embryonic expression of TBX5 has been found in the human retina. This is the first report of ocular findings in two unrelated families with mutations in the TBX5 gene. METHODS: Six living persons affected with HOS and 10 unaffected family members were subjected to mutation analysis and complete ophthalmological examination, including electrophysiological examinations (EOG and flash ERG). RESULTS: A heterozygous single base-pain substitution in exon 5 (408C --> A) was detected in all affected patients. All examined affected patents were ophthalmological asymptomatic with normal EOG. A scotopic elongated b-wave latency was found in affected family members who were older than 35 years. The ERG was normal in the young patients. CONCLUSIONS: Haploinsufficiency of TBX5 alters the dorsal-ventral polarity in developing eye vesicles without amy detected functional loss in human. Slight ERG abnormalities later in life may be a result of changes induced by the inner ganglion cell layer in the inner nuclear layer.

[Corneal wound healing after hyperopic PRK and LASIK]. / Korneale Wundheilungsreaktionen nach hyperoper PRK und LASIK.

BACKGROUND: The purpose of this study was to investigate the influence of different postoperative treatments on the wound healing reaction in the anterior stroma after PRK and in the interface area after LASIK. METHODS: Seventy-two corneal buttons of refractively treated rabbit eyes underwent different postoperative eyedrop regimens with antibiotics and/or steroids or additional UV-B irradiation. Morphological and immunohistological investigations were performed 6 months postoperatively by light and transmission electron microscopy. RESULTS: PRK eyes showed interdigitations between the epithelia and the anterior stroma. LASIK-treated eyes showed only minor changes between epithelia and stroma in the incisional region. Only a slight increase in deposits of fibrillar extracellular matrix components were detectable in the interface region. CONCLUSIONS: The clinically important problem of haze after PRK is caused by the interdigitations between epithelia and anterior stroma. The delicate wound healing reactions in the interface region in LASIK eyes corresponded to the clinically visible minor changes in these corneas.

[Radiotherapy for Graves' ophthalmopathy]. / Radiotherapie der endokrinen Orbitopathie.

Graves' ophthalmopathy (GO) is the most frequent extrathyroidal manifestation of Graves' disease, an autoimmune disorder of the thyroid, whereas the precise pathogenesis still remains unclear. In Hashimoto's thyroiditis the occurrence of proptosis is an extremely rare event. The therapy for middle and severe courses of GO shows in partly disappointing results, although several therapy modalities are possible (glucocorticoid therapy, radiotherapy, antithyroid drug treatment, surgery). All these therapies lead in only 40 - 70 % to an improvement of the pathogenic symptoms. An intensive interdisciplinary cooperation is necessary to satisfy the requirements for the treatment of Graves' ophthalmopathy. As a consequence of the very different results of the few of clinical studies that were accomplished with reference to this topic, treatment by radiotherapy in the management of the disease is presently controversially discussed. In the German-speaking countries the radiotherapy is, however, firmly established as a therapy option in the treatment of the moderate disease classes (class 2-5 according to NO SPECS), especially if diplopia is present. This article describes the sequences, dosages and fractionation schemes as well as the risks and side effects of the radiotherapy. Altogether, radiotherapy is assessed as an effective and sure method. The administration of glucocorticoids can take place before the beginning of or during the radiotherapy. For the success of treatment the correct selection of patients who may possibly profit from a radiotherapy is absolutely essential. By realising that GO proceeds normally over a period of 2-5 years, which is followed by a period of fibrotic alteration, the application of the radiotherapy in the early, active phase is indispensable. A precise explanation for the effects of radiotherapy in treatment of the GO does not exist at present. The determination of the most effective irradiation doses was made from retrospectively evaluated collectives. Recently the results of a national survey of all German RT departments were published, initiated by the working group of the DEGRO (German Society of Radiooncology). In the most of the German radiooncology departments irradiation with 8 to 10 x 1.8-2.0 Gy 5 x weekly to 16 or 20 Gy is standard. Two recently published prospective German studies pointed out the equivalence of the effectiveness of a short therapy in low dose ranges up to 2.4 Gy as well as of a low proportioned irradiation during a longer period in relation to a standard therapy with 20 Gy. That is why at the moment it is not possible to give a definite recommendation with reference to dosages or the fractionation schemes. In 2003 the first European group (European Group on Graves ' Orbitopathy Experience -- EUGOGO) was founded for pursuing investigations of GO in multi-centric studies, mainly to improve therapy results.

[Results of wavefront-guided LASIK]. / Ergebnisse der wellenfrontgestützten LASIK.

BACKGROUND: Wavefront-guided LASIK procedures provide patients with customized corneal treatments. The computer ablation profiles correct both spherical and/or cylindrical errors of refraction and aberrations up to the fifth order. METHODS: We performed wavefront-guided LASIK treatments on 62 patients using the Keracor 217 Z. The spherical equivalent was -6.11 +/-2.29 D on the average. Data collected for 3 months were evaluated to determine the predictability, efficacy, stability, and safety of the refractive procedure. RESULTS: We found good predictability of the refractive result after correcting -1 to -6 D of myopia. Beyond -7 D there were over- and undercorrections of +/-2 D in 10% of the procedures. A UCVA of 0.8 or better was observed in 53% of the patients 3 months postoperatively, and 75% of the patients reached a BCVA of 0.8 or better. After 3 months 6% lost 2 lines, 22% lost 1 line, 22% of the patients gained 1-2 lines, and BCVA remained unchanged in 55%. The fluctuation of the refraction was about -0.23 D during the first 3 postoperative months. CONCLUSIONS: The low and middle range of myopia can be corrected very accurately using the wavefront technology. Higher degrees of myopia face both under- and overcorrections. Postoperative refractions become stable very quickly. However, the visual acuity changes even 6 months postoperatively. From our point of view, wavefront correction by LASIK should be more reliable in terms of centration, accuracy, and standardization to get better results.

[The use of intracorneal rings in penetrating keratoplasty]. / Zum Einsatz von Nahtspannringen bei perforierenden Keratoplastiken.

BACKGROUND: The visual rehabilitation after penetrating keratoplasty (PKP) is affected by postoperative corneal astigmatism. Up to now studies were focused on different trephine systems as well as the suture techniques. A new option for reducing postoperative corneal astigmatism could be the implantation of an intracorneal ring. PATIENTS AND METHODS: Over a period of 2 years we implanted in 20 patients, who were suffering from keratoconus, Fuchs' dystrophy or bullous keratopathy, an 8-mm cobalt-molybdenum-titanium intracorneal ring in a prospective clinical trial. We used the guided trephine system (GTS) for preparation and a 10-0 nylon double running suture. The mean follow-up period was 16.2 months. A control group of 20 additional patients who underwent PKP was randomized. Topographic astigmatism as well as the spherical equivalent was evaluated after 1, 3, 6 and 12 months, respectively. RESULTS: Although a lower topographic astigmatism in the intracorneal ring group was reached 12 months postoperatively (3.0 dptr., SD 1.2 versus 4.0 dptr., SD 1.8) no statistical significance was found. The spherical equivalent in that group was lower during the complete evaluation period with a hyperopization in both groups as well. We did not see any immunological reactions caused by the ring. CONCLUSIONS: Whether the intracorneal ring could be a useful addition to PKP is not yet clear. Therefore more patients need to be enrolled and further studies established.