A steep peripheral ring in irregular cornea topography, real or an instrument error?

Peripheral ring opacity of the cornea.

(i) A 59-year-old Caucasian male presented at the casualty department complaining of pricking in the right eye. Symptoms were caused by a marginal infiltrate and this resolved on conventional therapy. A recurrence one month later also responded well. Each cornea presented an arcus senilis and, in the zone ofstroma affected by the arcus, an additional opacity could be seen. This was identical in...

The topography of the central and peripheral cornea.

PURPOSE To investigate the topography of the central and peripheral cornea in a group of young adult subjects with a range of normal refractive errors. METHODS Corneal topography data were acquired for 100 young adult subjects by a method that allows central and peripheral maps to be combined to produce one large, extended corneal topography map. This computer-based method involves matching t...

Imaging of the cornea: topography vs tomography.

Refractive Surgery Correcting the Irregular Cornea

AUGUST 2011 CATARACT & REFRACTIVE SURGERY TODAY 31 P rogressive, asymmetrical corneal steepening associated with an increase in myopic and astigmatic refractive errors, combined with midperipheral and/or peripheral corneal thinning, represents a constellation of findings in ectatic corneal disorders (eg, keratoconus and pellucid marginal degeneration). These entitites are associated with asymme...

The ring of real-continuous functions on a topoframe

 A topoframe, denoted by $L_{ tau}$,  is a pair $(L, tau)$ consisting of a frame $L$ and a subframe $ tau $ all of whose elements are complementary elements in $L$. In this paper, we define and study the notions of a $tau $-real-continuous function on a frame $L$ and the set of real continuous functions $mathcal{R}L_tau $ as an $f$-ring. We show that $mathcal{R}L_{ tau}$ is actually a generali...