US FDA clinical trial of the Tetraflex potentially accommodating IOL: comparison to concurrent age-matched monofocal controls

J Refract Surg. 2010 Oct;26(10):723-30. doi: 10.3928/1081597X-20091209-06. Epub 2009 Dec 15.


Purpose: To assess the efficacy of the Tetraflex (Lenstec Inc) intraocular lens (IOL) to provide enhanced near reading ability and spectacle independence relative to a monofocal control IOL in bilaterally implanted eyes tested binocularly.

Methods: A prospective, age-matched, non-randomized US Food and Drug Administration clinical trial of 255 Tetraflex and 101 monofocal IOL control patients was performed. To date, 239 Tetraflex and 96 control patients were examined at 12 months postoperatively.

Results: At 12 months postoperative, the Tetraflex patients read better than the controls at print sizes of 20/80 (P=.04), 20/63 (P=.01), 20/50 (P<.001), 20/40 (P=.001), 20/32 (P<.001), and 20/25 (P=.001). The proportion of patients reading at a speed of ≥80 words per minute was significantly higher with the Tetraflex IOL (P=.003). Ninety-six percent of Tetraflex patients reported never wearing glasses for distance compared with 80% of control patients (P<.001). Seventy-five percent of the Tetraflex patients reported near spectacle wear either never or only occasionally for small print and/or dim light (21% never) compared with 46% of control patients (P<.001) (9% never). Near add power requirement for corrected near visual acuity was less in the Tetraflex group (P<.001); 28% of Tetraflex patients required ≤1.25 diopters of near add, compared to only 7% of control patients. Spectacle independence, as measured by the proportion of patients with uncorrected distance visual acuity of 20/25 or better and various degrees of uncorrected near visual acuity, was also significantly better (P<.001) as was distance-corrected near visual acuity (P<.001).

Conclusions: The results support the efficacy of the Tetraflex IOL to provide enhanced near reading ability and spectacle independence relative to a monofocal IOL control.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Accommodation, Ocular / physiology*
  • Aged
  • Cataract Extraction*
  • Eyeglasses
  • Female
  • Follow-Up Studies
  • Humans
  • Lens Implantation, Intraocular*
  • Lenses, Intraocular*
  • Male
  • Prospective Studies
  • Prosthesis Design
  • Reading
  • Refraction, Ocular / physiology
  • Treatment Outcome
  • United States
  • United States Food and Drug Administration
  • Visual Acuity / physiology