[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.

[Retinal color Doppler scanning of arteria centralis retinae by retinal diseases and healthy people]. / Farbduplexsonografie der Arteria centralis retinae bei retinalen Erkrankungen und bei Gesunden.

BACKGROUND: The purpose of the study was to analyse retinal vascular diseases, a frequent reason for the sudden loss of vision, with the help of duplex Doppler ultrasonography as a non-invasive procedure, and to reproduce the results known from the literature using a common clinical device, thus allowing for an inexpensive out-patient examination. METHOD: 50 volunteers without eye diseases and with normal blood pressure, 8 patients with central retinal artery occlusion, and 24 patients with central retinal vein occlusion were examined. The study was conducted for the first time with a common device, a duplex Doppler unit (EccOcee SSA 340 A; Toshiba) using a 7 MHz microconvex array transducer. RESULTS: The observed peak velocity was 10.41 +/- 2 cm/s in normal subjects and therefore statistically significantly lower compared to patients with central retinal artery occlusion (6.5 +/- 1.2 cm/s) and those with central retinal vein occlusion (8.4 +/- 1.7 cm/s). The end diastolic velocity was also significantly lower in both groups of patients. With a lower statistical level of significance, it was also found that the second eye of patients with retinal vascular diseases shows a lower peak velocity in comparison to the control persons. CONCLUSIONS: We have examined the haemodynamics of the eye with respect to the blood flow velocity in the central retinal artery while trying to keep the other influencing factors neutral. The measured velocity is in accordance with the results known from the literature. We have thus confirmed that the blood flow in the central retinal vessels can be measured also with a less powerful device. Being simple, our method can easily be reproduced and is perfectly suited for measuring the systolic/diastolic flow at the optic nerve. Our observation of a generally lower flow velocity in cases of known high-risk patients whose second eye shows a retinal occlusion suggests that therapeutic consequences and prognoses can be derived whenever duplex Doppler ultrasonography yields abnormally low values.

[Keratoconus: epidemiology, risk factors and diagnosis]. / Keratokonus: Epidemiologie, Risikofaktoren und Diagnostik.

Keratoconus is a bilateral, non-inflammatory and progredient corneal ectasia with an incidence of approximately 1 per 2,000 in the general population. Within the second decade of life the cornea develops a conical shape, due to thinning of the corneal stroma with subsequent irregular astigmatism and myopia leading to marked impairment of vision. The most common presentation of the keratoconus is as a sporadic disorder, but it has long been recognized that a significant minority of patients exhibit a family history as an autosomal dominant mode of inheritance. Most investigators suggest complete penetrance of predisposing factors with variable phenotypic expression. In some patients heterozygous mutations in the VSX1 gene are described as the underlying gene defect. An association with Down syndrome, monosomia X (Turner syndrome), Leber's congenital amaurosis, mitral valve prolaps, collagenosis, retinitis pigmentosa and Marfan syndrome is described. The role of corneal cells in the pathogenesis of keratoconus is supported by the published reports of recurrence of keratoconus in eyes after penetrating keratoplasty due to graft repopulation by the recipient cells. Placido-based computeed videokeratographic corneal curvature mapping systems, linked with pachymetry, are useful for identifying overt and subclinical cases of keratoconus. Different indices may quantify the clinical features of keratoconus and may improve the classification. We compared videokeratometric data (Fourier series harmonic analysis and wavefront analysis) in eyes with keratoconus to answer the question of which parameters are useful for early diagnosis of keratoconus.

[Correction and induction of high-order aberrations after standard and wavefront-guided LASIK and their influence on the postoperative contrast sensitivity]. / Korrektur und Induktion von Aberrationen höherer Ordnung nach Standard- und wellenfrontgeführter LASIK und deren Auswirkungen auf das postoperative Kontrastsehen.

BACKGROUND: Wavefront-guided LASIK-treatments should reduce high-order aberrations (HOA). However, both the microkeratome cut as well as the ablation itself induce HOA. The purpose of this study was to investigate the amount of corrected preoperative measured HOA and induction of new HOA. METHODS: In this retrospective study 67 eyes of 45 myopic patients (- 2 to - 8.1 D SE; spherical equivalent) were treated by standard and wavefront-guided LASIK (Keracor 217z). Pre- and postoperative measurements of total aberrations and contrast sensitivity were performed. The follow-up time was 5.7 +/- 0.9 months. RESULTS: Patients with preoperative increased aberrations of 3rd and 4th order and myopia up to 5 D showed a slightly reduction of wavefront deformation. Cases of higher myopic corrections and lower preoperative spherical aberrations developed an increase of spherical aberrations after LASIK. The changes of other HOA showed no correlation with the amount of corrected myopia. Up to - 5 D patients showed the trend to better postoperative contrast sensitivity under 3 and 85 cd/m (2) after wavefront-guided LASIK than after standard LASIK. A significant advantage of wavefront-guided LASIK can be detected under a spatial frequency of 3 CPD (cycles per degree) and 85 cd/m (2). No advantages of any treatment procedure were shown after higher myopic corrections. CONCLUSION: If preoperative aberrations of 3rd and 4th order were increased and the myopia is < 5 D (SE) -- wavefront-guided LASIK can reduce total ocular HOA. Aberrometric findings after wavefront-guided LASIK in patients with lower preoperative HOA and myopia > 5 D (SE) are comparable with the results after standard treatment.

[Idiopathic orbital inflammatory syndrome (orbital pseudotumors): diagnosis and therapy]. / Idiopathische entzündliche intraorbitale Fibrosklerose: Diagnostik und therapeutische Möglichkeiten.

BACKGROUND: Pseudotumors of the orbit comprise a group of idiopathic inflammatory processes and are, except for endocrine orbitopathy, the most common reason for exophthalmos in adults. Orbital pseudotumors, also called idiopathic orbital inflammatory syndrome (IOIS), can be determined from orbital involvement in systemic fibrosing diseases. Finding the correct diagnosis can be challenging. Due to the topographic relations of the orbit to neighbouring structures, a multidisciplinary cooperation is highly recommended. CASE REPORT: We report a case of a 42-year-old woman with unilateral exophthalmos. Additionally we found impaired motility of the affected bulbus, ptosis and reduction of visual acuity. Orbital MR imaging demonstrated dense fibrotic masses filling the whole orbita including the extraocular muscles as well as the optic nerve. Tissue specimens were extracted while performing orbital decompression via a lateral orbitotomy. Histological examination revealed a lymphatic infiltration and fibrotically destroyed tissue containing the lacrimal gland. After surgical decompression, oral steroid therapy and immunotherapy, a recovery of the visual loss could be seen. CONCLUSIONS: Intraorbital fibrosclerosing pseudotumors often require a difficult long-term treatment. Therapeutic options are steroid therapy, immunotherapy, radiotherapy and surgery. The diagnostic steps include blood tests, ultrasound, CT and/or MRI as well as histological differentiation. Solid tumors and orbital involvement in diseases of the hematopoetic system have to be excluded. Since intraorbital fibrosis can be accompanied by manifestations in various other organs, a complete investigation of the body and thorough follow up are crucial.

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.

[Quantitative assessment of topographical parameters to differentiate keratoconus from pellucid marginal corneal degeneration and ]. / Quantitative Evaluierung topographischer Parameter zur Differenzierung von Keratokonus und pelluzidaler marginaler Hornhautdegeneration.

INTRODUCTION: The purpose is to compare videokeratometric data (Fourier series harmonic analysis and wave-front analysis) in eyes with ectatic corneal disease (keratoconus; pellucid marginal corneal degeneration [PMCD]) and to determine parameters for early diagnosis and distinction of keratoconus and PMCD. PATIENTS AND METHODS: 13 eyes with PMCD, 32 eyes with keratoconus and 18 healthy eyes were included. Computerized videokeratographic methods were assessed, using Fourier series harmonic analysis, Zernike coefficients and eccentricity. RESULTS: Irregular astigmatism (Fourier series harmonic analysis: decentration and/or irregularity) and the aberration coefficient were out of the normal range in all pathologic eyes. Both the nasal and the temporal eccentricities were greater than 0.63 in all PMCD patients, whereas either the superior or the inferior eccentricity was negative in all patients. In keraotoconic eyes, all quadrant eccentricities were positive and greater than 0.4. CONCLUSIONS: Irregular astigmatism and the aberration coefficient are useful parameters in detecting ectatic corneal disease using a computerized videokeratoscope. The calculation of the spherical equivalent (Fourier series harmonic analysis: no decrease of spherical equivalent in PMCD subjects) and of quadrant eccentricities are useful tools in distinguishing PMCD and keratoconus.

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.

[Usability of self-tonometry under ambulatory conditions to obtain daily profiles of intraocular pressure at home]. / Anwendbarkeit der Selbsttonometrie unter ambulanten Bedingungen zur Gewinnung von Tagesprofilen des intraokularen Druckes.

BACKGROUND: Diurnal profiles of intraocular pressure at opening times in the doctor's office do not deliver enough information, especially nightly and early morning measurements are lacking. Self-tonometry using the automatic self-tonometer "Ocuton S" might be suitable to achieve valid 24-hour IOP profiles without the need to stay in a hospital. MATERIALS AND METHODS: 96 people were taught to use the automatic self-tonometer once. Those who had learnt self-tonometry after this training underwent a diurnal IOP profile for 24 hours in the hospital using Goldmann tonometry and self-tonometry every 4 hours at the same times of day. One to three days later, they created a third IOP profile at home using self-tonometry at the same intervals as at the hospital. The IOP profiles were then tested for equality. RESULTS: 50 people out of 96 were able to perform self-tonometry after one training session. The IOP measurements of all three IOP profiles did not differ by more than 2 mmHg and thus may be considered comparable. There was no significant difference between daily curves, either. CONCLUSIONS: Self-tonometry using the automatic self-tonometer "Ocuton S" appears to be suitable to record diurnal profiles of intraocular pressure at home.