Abstract
Purpose :
To compare the refractive predictability of the SRK-T (ST), Hoffer-Q (HQ), Holladay 1 (H1), and Olsen (OS) lens formulas in the DMEK triple procedure in short, medium, and long eyes.
Methods :
A retrospective review was conducted of a prospective consecutive series of DMEK triple cases performed at one center. Optical biometry was performed with the Lenstar. Standard cataract surgery with a one piece acrylic IOL was performed followed by DMEK surgery according to a published standardized technique: pre-stripped and S-stamped tissue provided by an eye bank, overstripping of the recipient, modified glass Jones tube, no-touch tap technique, and 20% SF6 gas bubble. Manifest refraction was measured at 6-months. The difference between the achieved spherical equivalent (SE) and the predicted SE was compared between the HQ, ST, H1, and OS formulas. Eyes were grouped by axial length (short: <22 mm; medium: 22-26 mm; and long: >26 mm).
Results :
60 consecutive eyes were included in the study. Among eyes < 22 mm (n=4), the mean differences between the predicted and achieved SE for the ST, HQ, H1, and OS formulas were -0.19 D, -0.43 D, -0.19 D, and 0.13 D, respectively. Among eyes 22-26 mm (n=53), the mean differences were 0.33 D, 0.37 D, 0.36 D, and 0.47 D, respectively. Among eyes > 26 mm (n=3), the mean differences were 0.07 D, 0.54 D, 0.44 D, and 0.17 D, respectively. In the 22-26 mm subgroup, the ST had a smaller difference compared to the H1 (p=0.03) but exhibited equivalence compared to the HQ (p=0.75) and OS (p=0.37).
Conclusions :
In eyes undergoing the DMEK triple, the SRK-T, Hoffer-Q, Holladay 1, and Olsen formulas may exhibit different gradations of predictability. If this postulate is confirmed in a larger study, it may be possible to refine the intraocular lens target (at this center it is -0.7 D to achieve emmetropia) according to the formula used by the surgeon.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.