Articoli Scientifici di Oftalmologia
Argomento : 2
Validation of an Objective Scoring System for Forme Fruste Keratoconus Detection and Post-LASIK Ectasia Risk Assessment in Asian Eye
Purpose: To investigate the efficacy of the SCORE Analyzer
(Bausch+Lomb TechnoLas, Germany) in detecting forme fruste
keratoconus (FFKC) in Asian eyes and validate its usefulness as
a risk assessment system for post–laser in situ keratomileusis
(LASIK) keratectasia.
Methods: We retrospectively evaluated corneal topographies with
the Orbscan IIz system and independently tested them with the
SCORE Analyzer through masked investigators. Eyes were classi-
fied into 2 groups: (1) The FFKC group included clinically and
topographically normal eyes with definite keratoconus in the
contralateral eye. (2) The control group included normal preoperative
topographies of patients with LASIK performed at least 4 years
before with no resultant keratectasia. The main outcome measures
were accuracy indicators: sensitivity, specificity, positive, and
negative predictive values. Parameters in the calculation of the
SCORE including irregularity at 3 mm, thinnest pachymetry, the
difference between central and thinnest pachymetry (CP 2 TP),
vertical decentration of the thinnest point, maximum posterior
elevation, and anterior elevation of the thinnest point were compared
in both groups.
Results: We analyzed 128 Orbscans of 128 Asian patients. There
were 24 FFKC eyes and 104 control eyes. SCORE was negative in 7
eyes (false negative) in the FFKC group and was positive in 2 eyes in
the control group (false positive). The sensitivity was 70.8%,
specificity 98.1%, positive predictive value 89.5%, and negative
predictive value 93.6%. Irregularity at 3 mm, thinnest pachymetry,
CP 2 TP, thinnest point decentration, maximum posterior elevation,
and anterior elevation of the thinnest point were significantly
different in both groups.
Conclusions: The SCORE Analyzer algorithm, developed and
validated in white eyes, was found to be valid and consistent in
Asian eyes, showing good sensitivity and specificity in FFKC
detection, and to be useful in objectively identifying cases at risk
of post-LASIK keratectasia.
Key Words: corneal topography, forme fruste keratoconus, postLASIK
keratectasia
(Cornea 2015;00:1–9)