Assessment of toric intraocular lens alignment by a refractive power/corneal analyzer system and slitlamp observation
Received 20 June 2009; received in revised form 16 August 2009; accepted 19 August 2009.
Purpose
To assess the validity of an internal optical path difference map of a refractive power/corneal analyzer system in determining the alignment of toric intraocular lenses (IOLs).
Settings
Private practices, Spring Hill, Brisbane, and Chermside, Australia.
Methods
This retrospective study comprised patients with more than 1.5 diopters of preexisting corneal astigmatism who had phacoemulsification and AcrySof toric IOL implantation. Preoperatively, the surgical eye was marked at the slitlamp microscope using a 4-point technique. The desired IOL orientation was marked with a Mendez marker based on the steep corneal axis. The toric IOL axis was measured 3 weeks postoperatively by rotating the slitlamp beam to align with the IOL axis indicator marks and using the Internal OPD Map on the Nidek OPD-Scan system. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, residual refractive sphere, and residual keratometric and refractive cylinders were also measured at 3 weeks.
Results
Postoperatively, the mean UDVA was 0.17 logMAR ± 0.18 (SD) and the mean CDVA, −0.01 ± 0.12 logMAR; 88.2% of eyes had a UDVA of 0.3 or better, and no eye lost lines of visual acuity. There was an 82.33% reduction in defocus equivalent and a 64.62% reduction in refractive cylinder. The mean IOL misalignment measured by slitlamp was 2.55 ± 2.76 degrees and by the internal map, 2.65 ± 1.98 degrees. The correlation between the 2 methods was highly significant (r = 0.99, P<.001).
Conclusions
Both refractive power/corneal analyzer system and slitlamp observation were reliable and predictable methods of assessing IOL alignment. The 4-point preoperative marking technique yielded clinically acceptable, accurate toric IOL alignment.
Financial Disclosure
No author has a financial or proprietary interest in any material or method mentioned.
From the Brisbane North Eye Centre (Carey), Chermside, Australia; School of Biomedical Sciences (Carey, Leccisotti, McGilligan, Goodall, Moore), University of Ulster, Northern Ireland; Ophthalmic Surgery Unit (Leccisotti), Casa di Cura Rugani, Siena, Italy
Corresponding author: Paul Carey, Brisbane North Eye Centre, 708 Gympie Road, Chermside, Queensland 4032, Australia.
Bill Watson and Kevin Vandeleur, FRACS, FRACO, Brisbane North Eye Centre, Chermside, Australia, offered advice and support.
ABSTRACT