(ALNeelain University, 2002-08) Madiha Sid Ahmed Ali
AllS'I'RAC'l'
The aim of this study was to find arelationship between the corneal and
refractive astigmtism , (RA) & (CA) and to show if it is possible to derive the
subjective astigmatism (SA) from kcralomctric reading (KR).
SO subjects(lOO eyes) were examined using Shin-nippon 9000 autorelkeratometer
for RA and CA measurements , and subjective results were obtained .
The difference in location of the axes of RA with CA and CA with SA was
approximately same .There was no fixed relation in the axes .
RA and SA axes exhibited small variation , §i5° difl”crcnce was the most
(39.3%) , followed by £il0° (22.7%). l
The dioptric difference of i0.75D and less between RA and CA was (95.8%)
(95.7%) between CA and SA and (95.7%) between RA and SA.
20.1% for RA with CA , 25.6% for CA with SA and 18.3% for RA with SA
were the difference of si0.50D.
CA was agreed RA in l8.2%,with SA in 19.2% while RA and SA agreed in
32.6% .
Generally , amathematical formula for the relation of RA with CA could not be
drown . \
Key words : refractive , corneal, subjective,astigmatism .
ll
