Mechanism of action of the tetraflex accommodative intraocular lens.
OBJECTIVE
To investigate the mechanism of action of the Tetraflex (Lenstec Kellen KH-3500) accommodative intraocular lens (IOL).


METHODS
Thirteen eyes of eight patients implanted with the Tetraflex accommodating IOL for at least 2 years underwent assessment of their objective amplitude-of-accommodation by autorefraction, anterior chamber depth and pupil size with optical coherence tomography, and IOL flexure with aberrometry, each viewing a target at 0.0 to 4.00 diopters of accommodative demand.


RESULTS
Pupil size decreased by 0.62 ± 0.41 mm on increasing accommodative demand, but the Tetraflex IOL was relatively fixed in position within the eye. The ocular aberrations of the eye changed with increased accommodative demand, but not in a consistent manner among individuals. Those aberrations that appeared to be most affected were defocus, vertical primary and secondary astigmatism, vertical coma, horizontal and vertical primary and secondary trefoil, and spherical aberration.


CONCLUSIONS
Some of the reported near vision benefits of the Tetraflex accommodating IOL appear to be due to changes in the optical aberrations because of the flexure of the IOL on accommodative effort rather than forward movement within the capsular bag.
Aston University, School of Life and Health Sciences, Birmingham, UK. j.s.w.wolffsohn@aston.ac.uk
James S
JS
Wolffsohn
Leon N
LN
Davies
Navneet
N
Gupta
Shehzad A
SA
Naroo
George A
GA
Gibson
Toshifumi
T
Mihashi
Sunil
S
Shah
D000065:Accommodation, Ocular / Q000502:physiology*; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008875:Middle Aged; D011474:Prosthesis Design; D012029:Refraction, Ocular / Q000502:physiology