Tomey TMS-5 - 3.8 Utilities

3-49
Instantaneous Power This is the local corneal curvature map of the corneal shape,
and conversion to refractive power is performed by paraxial
calculation using the conversion refractive index. Compared
to the Axial Power map, changes in a specic point on the
cornea can be reected on the map more clearly.
Therefore, the rapid change from a normal corneal
curvature to the radius of a shrunken corneal curvature
due to keratoconus can be shown more clearly. Similarly,
the border between a section cut by laser due to PRK and
its surrounding area is also emphasized.
[Keratometric]
This is the conventional instantaneous map of TMS.
Similar to “Axial Power [Keratometric],” 1.3375 is used
for conversion to refractive power.
[Posterior]
This is the instantaneous power map of the posterior.
This map is drawn regarding the anterior corneal
center to be the reference, and paraxial calculation is
performed using the refractive index (cornea = 1.376
and aqueous humor = 1.336) of the Gullstrand model
practice eye for conversion to refractive power.
[Real]
This is the total power map of both anterior and
posterior.
The refractive power is calculated by adding the
corneal thickness correction to the sum of anterior and
posterior refractive power.
(Fig. 1)