Large diameter lenses are usually needed to achieve adequate centration and pupillary coverage in pellucid marginal degeneration, although inferior edge standoff in the ectatic region of the cornea may be difficult to overcome. Due to the extreme inferior ectasias, J.D.’s lenses exhibited inferior edge standoff, right lens greater than left lens, and the lenses popped out occasionally, due to the interaction of the lower edge of the lenses with his lower lids as he blinked. J.D.’s Orbscan maps showed more advanced pellucid marginal degeneration in his right eye, with the greatest thinning (lower right map) inferiorly. The typical topography pattern of pellucid has been described as “two birds kissing,” “a handlebar moustache,” “crab claws,” or “butterfly wings.” Although the condition is usually bilateral, like keratoconus, it tends to be asymmetric, with the corneal irregularity and thinning more advanced in one eye than in the other. The area of greatest thinning in keratoconus is usually central or paracentral in pellucid it is generally about 1.0 mm above the inferior limbus. Pellucid marginal degeneration usually appears between the ages of 20 and 40 and results in the development of high degrees of astigmatism as it progresses.
On the basis of the corneal topography, pellucid marginal degeneration, rather than keratoconus was diagnosed. Test Procedures, Fitting/Refitting, Design & Orderingīiomicroscopy: Inferior corneal thinning negative for Vogt’s striae Fleischer’s ring OU.Ĭorneal Topography: An inferior butterfly-shaped region of corneal steepening was present. He stated that both of his GP lenses pop out of his eyes, more often his right than his left.
J.D., a 42-year-old white male, presented with a history of “keratoconus” OU that was diagnosed at a commercial optical chain. Pellucid Marginal Degeneration: Phyllis Rakow, COMT, FCLSA Background
0 kommentar(er)
