Symposien Freitag

Newer treatment modalities have dictated the necessity of diagnosing ectatic disease both with greater specificity and at an earlier stage than was both previously possible and required. While multiple topographic and tomographic parameters have been proposed, no single parameter meets current clinical requirements. An analysis of the screening and diagnostic potential of various parameters will be discussed. Potential parameters for documenting progression will be presented.

Corneal refractive surgery is extremely successful in the vast majority of patients. One rare but important complication is thinning and protrusion of the cornea, often termed keratectasia. Risk factors include abnormal pre-operative topography and tomography, corneal thinning, high myopia and young age, but known risk factors do not predict all cases. Methods of diagnosis and a variety of treatment options will also be discussed.

Contact lenses of various types are an essential part of the management of patients with keratoconus and can be used to improve vision and delay or eliminate the need for surgery. This talk will review the different types of contact lenses currently used for keratoconus, including rigid gas-permeable lenses, hybrid lens, and both commercially-available and individually-customized scleral lens. Strategies to improve contact lens acceptance and reduce potential complications will be emphasized.

The spectrum of stage-related therapy of keratoconus has been broadened through the minimally invasive femtosecond-assisted implantation of intracorneal ring segments (Intacs). Although some potential complications may arise particularly with the mechanical tunnel dissection, the Intacs SK implantation appeared to be an effective method in improving the UCVA and BSCVA and at the same time seemed to stabilise the ectatic corneal condition in patients with keratoconus.

Compared to penetrating keratoplasty, DALK provides similar refractive results and postoperative astigmatism. But in contrast to penetrating keratoplasty, there are no endothelial immune reactions after DALK. This is especially relevant in young keratoconus patients and patients with e.g. neurodermitis. So according to AAO technology assessments, DALKs is a safer proecedure compared to penetrating keratoplasty. Surgery in DALK is more complicated and lasts longer compared to penetrating keratoplasty. That is one reason why DALK still is only performed regularly in a few cornea centers in Europe. Nonetheless due to increased safety, similar refractive results, absent immune reactions and the option to double use one donor tissue for two recipinets by combining DMEK and DALK, DALK is the standard form of care for patients with keratoconus at the Department of Ophthalmology in Cologne and in several other cornea centers.

To compare the intraoperative feasibility and postoperative outcome of the excimer and femtosecond laser trephination approaches during PKP for keratoconus. Prospective clinical studies have shown that the technique of non-contact excimer laser PKP results in significantly less "all-sutures-out" astigmatism, higher regularity of the topography and better visual acuity than the motor trephine. In addition, keratometric astigmatism and incidence of immune reactions after femtosecond laser PKP in keratoconus are significantly higher than after excimer laser PKP.

Visual loss in Schnyder corneal dystrophy results from progressive corneal opacification caused by abnormal deposition of corneal cholesterol and phospholipid. The causative gene UBIAD1 is a cholesterol metabolism gene and also catalyzes synthesis of human vitamin K (MK-4). Further work has uncovered UBIAD1 mutations in bladder cancer, and in Drosophila Parkinson´s disease. Investigation of Schnyder dystrophy may lead to inroads in our understanding of the pathogenesis of bladder cancer and Parkinson’s disease as well as suggests a link between Vitamin K metabolism and cholesterol metabolism.