Pellucid marginal corneal degeneration: evaluation of the corneal surface and contact lens fitting.
OBJECTIVE
To quantify corneal irregularities, to describe the fitting with contact lenses, and to answer the question whether or not contact lenses with a special back surface design could improve visual acuity in patients with pellucid marginal corneal degeneration (PMCD).


METHODS
13 eyes were fitted with contact lenses with a special back surface. Videokeratographic data were assessed. The patients were followed up for an average period of 22.2 months. Lens tolerance and corrected visual acuity were evaluated.


RESULTS
The mean eccentricity did not exceed 0.7 in all patients. Either the superior or the inferior eccentricity, or both, were negative in all patients. Using Fourier analysis all PMCD subjects showed an increased irregular astigmatism of the anterior cornea. Using Zernike coefficients seven eyes (53.8%) had a higher order aberration root mean square error (HOA RMS error) out of the normal range. The visual acuity with contact lenses improved in all eyes with an average increase of 2.7 lines (maximum eight lines). No serious complications were observed.


CONCLUSIONS
Quantitative evaluation of videokeratographic data may help to diagnose PMCD and to distinguish PMCD from other ectatic corneal diseases. Contact lenses with a special back surface design can improve visual acuity and lens tolerance.
Gruenauer-Kloevekorn
C
C
Department of Ophthalmology, Martin-Luther-University, Ernst-Grube-Strasse 40, 06097 Halle, Germany. claudia.gruenauer-kloevekorn@medizin.uni-halle.de
Fischer
U
U
Kloevekorn-Norgall
K
K
Duncker
G I W
GI
D000328:Adult; D001251:Astigmatism / Q000209:etiology / Q000503:physiopathology / Q000628:therapy; D003261:Contact Lenses; D003316:Corneal Diseases / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D017755:Prosthesis Fitting / Q000379:methods; D016896:Treatment Outcome; D014792:Visual Acuity