[Comparison of EyeSys videokeratoscope algorithms in the evaluation of idiopathic and postoperative astigmatism].
OBJECTIVE
To compare the accuracy and reproducibility of the Eye Sys videokeratoscope algorithms for analyzing idiopathic and surgery-induced astigmatism analysis.


METHODS
Refractive astigmatism, videokeratoscopy (axial, tangential and refractive power), autorefractometry, autokeratometry, and keratometry were recorded in 20 patients with idiopathic astigmatism, 40 patients who had undergone cataract surgery and 40 patients who had undergone penetrating keratoplasty. For each eye, 2 successive videokeratoscopy were recorded.


RESULTS
Both cylinder and axis provided by the tangential algorithm are significantly less reproducible than the cylinder and axis provided by the axial and refractive algorithms (P < 0.001). Cylinders provided by the axial and refractive algorithms showed a stronger correlation with subjective cylinder (rs > 0.89; p < 0.001) than the cylinder provided by the tangential algorithm (rs = 0.66; p < 0.001). Both keratometric axis and autokeratometric axis showed the strongest correlation with subjective axis (rs > 0.92; p < 0.001). The accuracy and reproducibility were higher for the topographic "bow tie" patterns than for the other topographic patterns.


CONCLUSIONS
The axial and refractive algorithms of the Eye Sys videokeratoscope are more accurate and reproducible than the tangential algorithm for analyzing idiopathic or surgery-induced astigmatism.
Touzeau
O
O
Service d'Ophtalmologie, Hôpital Saint-Antoine, Paris.
Borderie
V
V
Chastang
P
P
Scheer
S
S
Allouch
C
C
Laroche
L
L
D000465:Algorithms; D001251:Astigmatism / Q000175:diagnosis* / Q000209:etiology; D002387:Cataract Extraction / Q000009:adverse effects*; D019781:Corneal Topography / Q000379:methods*; D003627:Data Interpretation, Statistical; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000009:adverse effects*; D015203:Reproducibility of Results