Collagen cross-linking in the treatment of pellucid marginal degeneration.

Pellucid marginal degeneration (PMD) is an uncommon cause of inferior peripheral corneal thinning disorder, characterized by irregular astigmatism. We analyzed a case of bilateral PMD patient and treated one eye with corneal collagen cross-linking (CXL) therapy. Corneal topography was characteristic for PMD. Visual acuity, slitlamp examinations, tonometry, and corneal thickness were observed. Simulated keratometric and topographic index values were detected with corneal topography. Uncorrected, LogMAR visual acuity has improved from +0.8 to +0.55 during the 6 months and +0.3 during the 8 months followup after CXL. Pachymetry values and intraocular pressure showed no changes. Keratometric values and topografic indexes disclosed no progression of the disease. CXL may postpone or eliminate the need of corneal transplantation in cases with PMD.

Scheimpflug imaging in anterior megalophthalmos.

We report an anterior megalophthalmos case with decreased corneal thickness and show the findings using Scheimpflug imaging. A 25-year-old male was diagnosed with anterior megalophthalmos. In both eyes, enlarged corneal length was measured. Beside a comparatively good visual acuity, a thin but clear cornea, a fairly deep anterior chamber, and central lens opacity were found. Scheimpflug images were taken using Pentacam HR. Scheimpflug-based imaging can provide us new data at the examination of this syndrome affecting the whole anterior segment.

Birefringence of cells grown in vitro and of mitotic chromosomes after staining with picrosirius red

Fibroblasts and neuroblastoma cells kept in monolayer cultures, as well as surface spreads of mitotic chromosomes, were stained with picrosirius red. Red staining (in normal light) and optical anisotropy of the stained structures (in polarized light) were observed intracellularly and in the chromosomes. The intracellular and extranuclear birefringence induced by staining with sirius red could not be abolished by digestion with collagenase prior to staining, or by treatments used to disrupt microtubules (vinblastine, colcemid) or microfilaments (cytochalasin B). We therefore propose that the parallelly-arranged intermediate filaments are responsible for the optical anisotropy induced by sirius red staining in these cells. In addition, the spatially oriented scaffold of chromosomes can be detected by sirius red-induced birefringence. These data argue against the collagen-specificity of picrosirius red staining and of the birefringence induced by this technique. Our results also suggest that picrosirius red staining combined with polarized light microscopy can be used to study the spatial orientation pattern of the intermediate filaments and chromosome scaffold.