1. Comparison of Autokeratometry and Manual Keratometry
The authors have no financial interest in the subject matter of this poster
Dr. A. Braganza,
M.K. Kummelil, A. Shetty
Narayana Nethralaya, Bangalore, India

2. Incidence of Astigmatism
15 to 25% of the cataract patients have a pre-existing astigmatism of 1.50 D or more
9-12% have a pre-existing astigmatism of 2.00 D or more
Less than 1% have a pre-existing astigmatism of more than 3 D
Commonest cause of poor post-op UCVA are residual spherical error & uncorrected pre-existing astigmatism
Biometry of 7,500 cataractous eyes. Hoffer KJ. AmJ Ophthalmol, 1980; 90:360–368; correction, 890
Prevalence of corneal astigmatism before cataract surgery, Ferrer-Blasco T, Montés-Micó R, Peixoto-de-Matos SC, González-Méijome JM, Cerviño A. JCRS June2009,

3. Purpose
To compare the keratometry values obtained by autokeratometry against those obtained by manual keratometry for accuracy and consistency.
With the advent of toric IOLs and toric refractive IOLs to correct astigmatism we felt the need to see which was the more valid method for pre-operative assessment of patients

4. Materials and methods
Patients meeting inclusion and exclusion criteria for intraocular lens implantation were included in the study after signing the informed consent
100 eyes of patients posted for cataract surgery underwent keratometry using a hand-held autokeratometer (NIDEK) and a manual keratometer (Bausch and Lomb) using a standardized protocol.
Repeat measurements were taken 5 minutes later to check for consistency.

5. Materials and methods
All patients underwent routine phacoemulsification through a clear corneal incision.
Manifest refraction was performed at 6 weeks post op and the post operative refraction was analysed to assess the accuracy of the “k” readings obtained by the 2 instruments.

6. Results Manual Automated T-test Steep K 44.09 + 1.22 44.18 + 1.32 0.74
Flat K
Mean K
Correlation coefficient
0.97
0.99
biometry was

7. Conclusion
There was no statistical difference between Manual and Automated Keratometry values
The repeatability of the tests was good when performed in a standardized fashion (correlation coefficient=0.97 & 0.99)
Steep axis of the post-operative K by both techniques correlated well with the refractive cylinder. (correlation coefficient=0.98 & 0.98)