Keratoconus detected by videokeratography in candidates for photorefractive keratectomy.
BACKGROUND
Patients with corneal shape abnormalities should be identified prior to photorefractive keratectomy (PRK). We used videokeratography screening to detect subclinical corneal abnormalities, including keratoconus, which might have been missed by conventional clinical evaluation.


METHODS
One hundred forty-six apparently normal myopic eyes (-1.00 to -7.00 diopters [D] with less than 1.50 D of cylinder) of 91 consecutive patients who were candidates for PRK were screened by videokeratography.


RESULTS
In 6 of 91 patients (7 of 146 eyes), unsuspected corneal shape abnormalities were detected by videokeratography. Two patients had definite keratoconus and three were classified as keratoconus suspects by inferior corneal steepening (Rabinowitz I-S index ranging from 1.62 to 6.20 D). One patient had early pellucid marginal degeneration.


CONCLUSIONS
Keratoconus suspects and contact lens-induced changes resembling keratoconus are present in the "normal" myopic population that presents for refractive surgery. Videokeratographic screening is the only effective means of identifying these and other corneal shape abnormalities.
Nesburn
A B
AB
Ophthalmology Research Laboratories, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Bahri
S
S
Salz
J
J
Rabinowitz
Y S
YS
Maguen
E
E
Hofbauer
J
J
Berlin
M
M
Macy
J I
JI
D000328:Adult; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007640:Keratoconus / Q000175:diagnosis*; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy; D012680:Sensitivity and Specificity; D014741:Video Recording