Purpose: In the present study we
have tried to find the most reliable intraocular lens (IOL) power calculation
formula in patients with keratoconus (KCN) and cataract.
Methods: In a prospective case
series between October 2010 and March 2012, eligible patients with cataract and
KCN underwent phacoemulsification with IOL implantation. Preoperatively, based
on IOL master keratometric data IOL power calculation was subsequently
performed by means of six well-known formulas: Haigis, Holladay 1 and 2, Hoffer
Q, SRKII, and SRKT. Postoperatively the “desired IOL power” was back-calculated
in order to determine the most accurate formula for IOL power calculation.
Results: Fourteen patients
(20 eyes) with nuclear sclerosis and KCN were cumulatively enrolled. The mean
age was 56.7 years±13.8 (SD) (range, 23 to 70 years). Nine patients (64%) were
males. In mild KCN subgroup, SRK II and SRK-T represent as the “matched formulas”
within defocus range of less than 1 D in 66.6% of cases. In moderate KCN
subgroup, Hoffer Q, Holladay 1, Holladay 2, SRK II and SRK-T II represent as the
“matched formulas” within defocus range of less than 1 D in 75% of cases.
Finally in severe KCN subgroup, SRK II represents as the “matched formula” in
50% of cases.
Conclusion: Findings of the
present study suggest that irrespective of axial length classification, the SRK
II formula can be considered as “the ideal formula” the one with the most
reliable outcome in all stages of KCN.
Iranian Journal of Ophthalmology 201426(2):66-71 © 2014 by the Iranian Society of Ophthalmology