Abstract
M.Phil.
Keratometric readings on three subjects were taken both
during pregnancy and postpartum. One subject was visually
non-compensated and did not require refractive correction, one
was a contact lens wearer and one had undergone radial
keratotomy. Twenty readings were taken by means of an
automatic keratometer on each eye, morning and afternoon,
every fortnight. The recent matrix method of optometric
statistical analysis was employed and the results graphically
compared and analysed.
Findings indicate diurnal variations including variation
in corneal curvature and variance through the course of normal
pregnancy. Most evident was an increase in keratometric
variation in all three subjects at the time of birth and a
substantial decrease in corneal refractive power in the
subject who had before undergone radial keratotomy. This
result may have far-reaching implications on the long term
prognosis of refractive surgery especially for females of
child bearing age.
Outliers representing transient increases in curvature
were most common in the vertical meridian (indicating possible
lid interaction), while the presence of bimodal distributions
suggests a sensitivity of the automatic keratometer to changes
in head posture.