Corneal power measurements in fixating versus anesthetized nonfixating children using a handheld keratometer.
OBJECTIVE
To compare keratometry measurements on a fixating patient with readings from the same nonfixating patient intraoperatively using the Nidek KM-500 handheld keratometer.


METHODS
Consecutive patients who were scheduled for strabismus or nasolacrimal surgery between 5 and 11 years of age were included in the study. Handheld keratometry was performed preoperatively on both eyes with the child fixating and intraoperatively with the child anesthetized. Three readings were taken on each eye. The steepest and flattest corneal meridians were recorded. Intraclass correlation coefficients were calculated to assess reliability, and interchangeability was assessed by the use of the Bland-Altman method.


RESULTS
Included in the study were 55 eyes of 28 patients. The average fixating keratometry reading was 44.10 +/- 1.45 D for right eyes and 44.12 +/- 1.42 D for left eyes. The average nonfixating keratometry reading was 44.06 +/- 1.62 D for right eyes and 44.02 +/- 1.54 D for left eyes. The intraclass correlation coefficient for the average keratometry obtained fixating versus nonfixating was 0.96 for right eyes and 0.95 for left eyes. The Bland-Altman analysis showed fairly large limits of agreement between readings, but most readings fall within the limits of variability. The mean time to obtain the intraoperative measurements was 4.26 minutes.


CONCLUSIONS
In our study the Nidek KM-500 handheld keratometer provided reliable readings when used intraoperatively on anesthetized nonfixating children and required minimal time to perform.
The Ohio State University College of Medicine, Department of Ophthalmology, Section of Pediatric Ophthalmology and Adult Strabismus, Columbus, Ohio, USA. david.rogers@nationwidechildrens.org
David L
DL
Rogers
G Rick
GR
Whitehead
Julie A
JA
Stephens
Rae R
RR
Fellows
Don L
DL
Bremer
Mary Lou
ML
McGregor
Richard P
RP
Golden
Cybil Bean
CB
Cassady
Gary L
GL
Rogers
D000293:Adolescent; D000758:Anesthesia; D002648:Child; D002675:Child, Preschool; D003315:Cornea / Q000033:anatomy & histology* / Q000601:surgery; D019781:Corneal Topography / Q000295:instrumentation* / Q000592:standards; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000592:standards; D009301:Nasolacrimal Duct / Q000601:surgery; D011300:Preoperative Care / Q000295:instrumentation / Q000592:standards; D015203:Reproducibility of Results; D013285:Strabismus / Q000175:diagnosis / Q000601:surgery*; D014851:Wakefulness