Stage-related therapy of corneal dystrophies.
ABSTRACT Corneal dystrophies typically result in a gradual bilateral loss of vision in a primary 'white eye' - often in conjunction with epithelial defects in later stages. Treatment of corneal dystrophies needs to be stage-related. To ensure a stage-related therapeutic approach, an adequate classification based on clinical, histopathological and genetic knowledge is indispensable. In principle, topical medications, contact lenses and various microsurgical approaches are applicable. In case of predominantly superficial dystrophies of the epithelium, basal membrane and/or Bowman's layer (map-dot-fingerprint, Meesmann, Lisch, Reis-Bücklers, Thiel-Behnke), recurrent epithelial defects may complicate the clinical picture. If conservative therapy with gels/ointments, application of therapeutic contact lenses and/or conventional corneal abrasion are not successful, phototherapeutic keratectomy (PTK) using a 193-nm excimer laser is the method of choice today. PTK can be repeated several times, thus post poning corneal transplantation (lamellar or even penetrating) for a long time. Three major goals may be achieved by PTK depending on the diagnosis: (1) to remove superficial opacities; (2) to regularize the surface and treat irregular astigmatism, and (3) to improve the adherence of the epithelium. In dystrophies with depositions predominantly in the stroma (e.g. granular, lattice, macular, recurrence on the graft), PTK may be a reasonable alternative to anterior lamellar or penetrating keratoplasty (PKP) depending on the exact localization of the lesions. Besides exact determination of the depth of depositions using a slit lamp, a preoperative topography analysis is indispensable. The therapy of endothelial dystrophies depends on diagnosis and age: Fuchs endothelial corneal dystrophy will need corneal transplantation (e.g. when visual acuity drops below 0.4). In contrast, transplantation will only be very rarely necessary in posterior polymorphous corneal dystrophy, but the intraocular pressure has to be checked frequently. Especially in elderly patients with reduced compliance, posterior lamellar keratoplasty - preferably in the form of Descemet stripping automated endothelial keratoplasty - may be performed instead of PKP. In case of congenital hereditary endothelial dystrophy, the best time point of PKP has to be determined with regard to amblyopia (surgery too late) and inadequate follow-up (surgery too early) together with parents and pediatric ophthalmologists on an individual basis. In conclusion, for stage-related therapy of corneal dystrophies, besides contact lenses, PTK and PKP, various techniques of lamellar keratoplasties represent an indispensable enrichment of our corneal microsurgical spectrum today.
SourceAvailable from: Eric G Romanowski[Show abstract] [Hide abstract]
ABSTRACT: To measure the diffusion of topical preparations of moxifloxacin, amphotericin B (AmB), and polyhexamethylene biguanide (PHMB) through silicone hydrogel (SH) contact lenses (CLs) in vitro. Using an in vitro model, the diffusion of three antimicrobials through SH CLs was measured. Diffused compounds were measured using a spectrophotometer at set time points over a period of 4 hr. The amount of each diffused antimicrobial was determined by comparing the experimental value with a standard curve. A biological assay was performed to validate the CL diffusion assay by testing antimicrobial activity of diffused material against lawns of susceptible bacteria (Staphylococcus epidermidis) and yeast (Saccharomyces cerevisiae). Experiments were repeated at least two times with a total of at least four independent replicates. Our data show detectable moxifloxacin and PHMB diffusion through SH CLs at 30 min, whereas AmB diffusion remained below the limit of detection within the 4-hr experimental period. In the biological assay, diffused moxifloxacin demonstrated microbial killing starting at 20 min on bacterial lawns, whereas PHMB and AmB failed to demonstrate killing on microbial lawns over the course of the 60-min experiment. In vitro diffusion assays demonstrate limited penetration of certain anti-infective agents through SH CLs. Further studies regarding the clinical benefit of using these agents along with bandage CL for corneal pathologic condition are warranted.Eye & contact lens 03/2015; DOI:10.1097/ICL.0000000000000121 · 1.68 Impact Factor
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ABSTRACT: We have used a focused and comprehensive ophthalmology patent database to characterize the international patenting landscape dedicated to the pharmacological treatment of cataract, corneal opacities and dystrophies, and complicated refractive errors. A total of 201 disclosures related to cataract or corneal clouding (published between 1982 and 2011), and 99 documents (published between 1991 and 2011) related to refractive or geometry errors were identified. Current applications for the treatment or prevention of primary cataract have ceased to address diabetic cataract specifically through the inhibition of glycation-specific mechanisms. The most innovative approaches for pharmacotherapy of the lens focus on phase separation inhibitors, modulators of the TGF-β pathway, and matrix metalloproteinase inhibition. Patenting for the prevention of secondary cataracts as a delayed complication of intraocular lens insertion follows similar routes. For keratoconus, progressive myopia and Avellino corneal dystrophy, the focus remains on efficiently stabilizing the corrected shape of the cornea in the course of orthokeratology treatments. We expect future patenting in the fields of our investigation to concentrate more heavily on molecular medicine, in close lockstep with biotechnology and genetic testing.05/2012; 1(2):165-75. DOI:10.4155/ppa.12.23
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ABSTRACT: The aim of this study was to describe a microkeratome-assisted 2-stage technique of superficial anterior lamellar keratoplasty (SALK) to manage Reis-Bucklers corneal dystrophy (RBCD).Cornea 07/2014; DOI:10.1097/ICO.0000000000000189 · 2.36 Impact Factor