[Treatment of keratoconus by collagen cross linking].

Background: We were able to show a significant increase in corneal stiffness of rabbit and porcine eyes after combined riboflavin/UVA-induced collagen cross-linking. In this study,we tried to treat keratoconus patients with this method to stop the progression of corneal ectasia.

Patients And Methods: We treated 16 eyes of 15 patients with progressive keratoconus and mostly moderate keratectasia (48-56 dpt).

Anterior lamellar keratoplasty with a microkeratome: a method for managing complications after refractive surgery.

Purpose: To demonstrate a technique of anterior lamellar keratoplasty with standardized and automated preparation of surface-parallel cuts in both donor and recipient appropriate for addressing several problems after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).

Methods: We report a noncomparative series of ten eyes with complications after LASIK and PRK. Lamellar cuts were performed in donor and recipient eyes by means of an automated microkeratome.

Experimental results of preparing laser-shaped stromal implants for laser-assisted intrastromal keratophakia in extremely complicated laser in situ keratomileusis cases.

Purpose: To evaluate the feasibility of laser-shaped stromal implants from a donor eye for correcting extreme high hyperopia with irregular astigmatism and an exceptionally thin corneal bed.

Methods: Thirty-one fresh enucleated porcine eyes were used. The procedure was initiated with mechanical de-epithelialization followed by a lamellar cut with a microkeratome, resulting in a hinged flap (thickness 150 microm, diameter 9.

Customized corneal ablation.

Refractive surgery is still one of the most innovative and evolving fields in ophthalmology. With the advent of customized ablation, a change in paradigm has been established: the primary goal of refractive surgery is not only to eliminate spectacles but to improve or at least prevent deterioration of the optical performance of the eye. Wavefront-guided refractive surgery has, as a new goal, to correct or at least minimize all optical aberrations of the eye, and consequently to improve or preserve visual performance, especially under scotopic conditions.

Aberration-sensing and wavefront-guided laser in situ keratomileusis: management of decentered ablation.

Purpose: To clarify the feasibility of aberration-sensing and wavefront-guided laser in situ keratomileusis (LASIK) to manage grossly decentered ablation and to discuss the limitations of the technology.

Methods: Three patients with previous decentrations of the ablation zone between 1.5 to 2.

V(H) mutation status, CD38 expression level, genomic aberrations, and survival in chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), biologic risk factors such as immunoglobulin variable heavy chain gene (V(H)) mutation status, CD38 expression level, and genomic aberrations have recently been identified, but the relative prognostic impact of the individual parameters is unknown. In the current study, we analyzed V(H) mutation status by polymerase chain reaction and sequencing (n = 300), genomic aberrations by fluorescence in situ hybridization (+3q, 6q-, +8q, 11q-, +12q, 13q-, t(14q), 17p-) (n = 300), and CD38 expression by triple-color FACS (CD5, CD19, CD38) (n = 157) in a unicentric CLL cohort. The prognostic influence of V(H) mutation rate and CD38 expression level was tested by maximally selected log-rank statistics.

Corneal myxoma.

Background: Myxomas are rare benign tumors that can be found most frequently in the heart. We report the clinical and histological findings in a very rare case of corneal myxoma, which is only the sixth case in the literature.

Case: A whitish elevated tumor of the anterior cornea developed in the left eye cornea of a 46-year-old man 2 years after luxation of the patient's lens into the anterior chamber and subsequent endothelial decompensation.

Optical low coherence reflectometry for noncontact measurements of flap thickness during laser in situ keratomileusis.

Objective: There is growing evidence that iatrogenic keratectasia after laser in situ keratomileusis (LASIK) for high corrections occurs more frequently than initially assumed, and that it may result from larger variation in flap thickness.

Design: Consecutive noncomparative case series

Participants: Thirty-four patients who underwent LASIK for myopia and astigmatism (first treatment group) and 10 patients who received re-LASIK (retreatment group).

Methods: Central corneal thickness and thickness of the lamella during LASIK were determined by optical low coherence reflectometry (OLCR) and contact ultrasound pachymetry.

Influence of corneal curvature on calculation of ablation patterns used in photorefractive laser surgery.

Purpose: The aim of this work was to clarify the influence of the effective illumination area and possible reflection losses that occur during laser-tissue interaction on the modeling of profiles for customized corneal ablation, such as wavefront-guided treatments.

Methods: The changes of the ablation depth per laser pulse due to the projection of a laser spot onto the corneal front surface and reflection losses at the air-tissue interface were calculated.

Results: Moving with a scanning-spot from the center of the cornea toward the limbus resulted in an increase of the effective illumination area and reflection losses, which led to a decrease in the ablation depth per laser pulse.

[Fundamentals of wavefront-guided refractive corneal surgery].

The clinical introduction of aberration-sensing and wavefront-guided refractive surgery opens new ways in diagnostic and therapy of high order optical aberrations of the human eye. The main application is the optimization of current treatment methods such as LASIK or PRK. The aim of wavefront-guided treatments is to omit the deterioration of the optical performance under mesopic conditions of the eye by the refractive treatment and, if possible, to increase contrast sensitivity by correcting the higher order aberrations.

Erbium: yttrium-aluminum-garnet laser induced vapor bubbles as a function of the quartz fiber tip geometry.

Background: The use of modern erbium: yttrium-aluminum-garnet (YAG) laser systems in opthalmic microsurgery requires a precise knowledge of the size and dynamics of the laser induced vapor bubbles. The aim of this work was to clarify the possibilities of controlling the vapor bubble shape and size by using an optimized fiber tip geometry for various ophthalmic applications with the erbium: YAG laser.

Methods: The mid-infrared radiation of free-running erbium: YAG laser was coupled optically into means of different low OH(-) quartz fiber tips to investigate the vapor bubble formation in water by high-speed photography.

[Ultrasound biomicroscopy diagnosis of traumatic choroid effusion without cyclodialysis].

Background: Chamber angle changes due to trauma represent a diagnostic challenge in modern ophthalmology and two examination techniques are compared: gonioscopy which has been used in ophthalmology for almost a century and is still undergoing continuous improvements and ultrasound biomicroscopy (UBM) which was introduced into clinical ophthalmology in 1991.

Case Report: We report the case of a 14-year-old boy with ocular trauma caused by a soft gun projectile. Gonioscopy showed a large goniosynechia in the presence of ocular hypotension, therefore, cyclodialysis was suspected.

Improvement in photorefractive corneal laser surgery results using an active eye-tracking system.

Purpose: To study the advantage of modern eye-tracking systems for photorefractive surgery.

Setting: Department of Ophthalmology, University of Zurich, Zurich, Switzerland.

Methods: Photorefractive surgery (photorefractive keratectomy and laser in situ keratomileusis) for myopia and myopic astigmatism was performed in 40 eyes with a commercially available medical excimer laser system.

[Does refractive surgery really make eyeglasses superfluous?].

Spectacles have become a problem of life-style in some societies. In the USA, in 1999 approximately 1 million LASIK operations have been performed to correct myopia and astigmatism and in Europe the frequency of refractive surgery stead by increases. However, only 3 to 5% of these operations are medically indicated.

[Supportive amblyopia treatment by means of computer games with background stimulation; a placebo controlled pilot study of 10 days].

Background: Computer programmes for visual stimulation may give new impulses to the field of amblyopia treatment by offering an option to shift the apparative visual training into the domestic sphere. Regarding this aspect we report on a placebo controlled study on a newly developed vision training consisting of a background stimulation by a drifting sinusoidal grating combined with a foreground game aimed to maintain the attention.

Materials And Methods: Fourteen amblyopia patients aged from 6 to 13 years participated in the study.

Stress wave amplitudes during laser surgery of the cornea.

Purpose: To determine the stress wave amplitudes generated during photoablation of the cornea using an argon fluoride excimer laser.

Design: Experimental study using porcine eyes.

Methods: Profiles of the stress wave amplitudes and enucleated human eyes along the axis of symmetry of porcine eyes and enucleated human eyes were measured using a miniature piezoelectric transducer.

Ocular optical aberrometer for clinical use.

Higher-order optical errors of the human eye are often responsible for reduced visual acuity in spite of an optimal spherical or cylindrical refraction. These optical aberrations are of natural origin or can result from operations in the eye that involve optical structures. The ocular aberrometer presented is based on Tscherning's aberroscope.

Understanding refraction and accommodation through "retinal imaging" aberrometry: a case report.

Purpose: A new form of aberrometry based on Tscherning optics has been proposed that captures the refraction and high-order aberrations of the eye with and without accommodation.

Design: Experimental clinical optics study.

Method: A green neodymium:yttrium-aluminum-garnet laser grid pattern is projected into the eye and viewed on the retina through a narrow, collimated aperture of 1 mm.

[Cavitation bubble formation during Erbium:YAG laser vitrectomy].

Background: Clinical and experimental studies demonstrated the potential advantages of Erbium:YAG laser vitrectomy for posterior segment surgery. However, a detailed knowledge on the laser-tissue interaction is needed for an optimization of new ophthalmic applications. The aim of this experimental work was to investigate the cavitation bubble formation during Erbium:YAG laser vitrectomy and to find optimized laser parameters and the best geometry of the aspiration port of the microsurgical probe.

Increased higher-order optical aberrations after laser refractive surgery: a problem of subclinical decentration.

Purpose: To study the clinical and theoretical effects of subclinical decentrations on the optical performance of the eye after photorefractive laser surgery.

Setting: Department of Ophthalmology, University of Dresden, Dresden, Germany.

Methods: Ocular aberrations were determined before and 1 month after uneventful photorefractive keratectomy (PRK) with the Multiscan laser (Schwind) in 10 eyes of 8 patients.

Clinical results of wavefront-guided laser in situ keratomileusis 3 months after surgery.

Purpose: To investigate the visual and refractive outcome of wavefront-guided laser in situ keratomileusis (LASIK) to correct myopic astigmatism.

Setting: Departments of Ophthalmology of the Universities of Dresden, Dresden, Germany, and Zurich, Zurich, Switzerland.

Methods: This prospective study comprised 35 eyes of 28 patients who had a mean preoperative spherical refraction of -4.

[Motion artifacts in the vitreous body during vitrectomy].

Background: Movements and vibrations of intraocular structures can be observed during vitrectomy with mechanical cutting systems. We experimentally compared these intraocular motion artifacts between mechanical and erbium:YAG laser vitrectomy.

Material And Methods: The intraocular structures were reliably simulated by a 0.

Manifest diabetes and keratoconus: a retrospective case-control study.

Purpose: To assess the influence of diabetes on the development of keratoconus to show whether biomechanical effects are also reflected in epidemiology. The two diseases have opposite impact on the biomechanics of the corneal stroma: manifest diabetes stiffens the cornea, whereas keratectasia weakens the tensile strength of the stroma.

Methods: The retrospective case-control study included files of 1,142 patients, with 571 patients in the case group (keratoconus patients) and 571 in the control group (clinical population).

[Irradiation of cornea with ultraviolet light and riboflavin administration as a new treatment for erosive corneal processes, preliminary results in four patients].

Background: Corneal melting is a serious condition and in many cases maybe managed only by surgery. UV-radiation with Riboflavin is a new method that may stop the melting process of the cornea.

Patients And Method: Four patients suffering from melting ulcera of the cornea of various origin underwent a single UV-radiation.