Contrast sensitivity after implantation of diffractive bifocal and monofocal intraocular lenses

• Published in: Journal of cataract and refractive surgery Vol. 24; no. 5; pp. 653 - 658
• Main Authors: Haaskjold, Erling, Allen, Eric David, Burton, Robert L., Webber, Susan K., Sandvig, Kjell U., Jyrkkiö, Hannu, Leite, Eugenio, Liekfeld, Anja, Philipson, Bo, Nyström, Alf, Wollensak, Josef
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.1998; Elsevier Science
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Cataract Extraction; Contrast Sensitivity; Female; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Male; Medical sciences; Middle Aged; Prospective Studies; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the eye and orbit; Visual Acuity; Human; Eye disease; Cataract; Sensitivity; Lens disease; Surgery; Bifocal; Implantation; Intraocular lens; Contrast; Anterior segment disease; Comparative study
• ISSN: 0886-3350; 1873-4502
• DOI: 10.1016/S0886-3350(98)80260-5

Purpose: To compare contrast sensitivity (CS) after implantation of a diffractive bifocal intraocular lens (IOL) and a monofocal IOL of similar design. Setting: Seven European centers. Methods: In this randomized, prospective study, CS was tested 5 months after cataract and IOL implantation surgery in 115 patients with a diffractive bifocal IOL and 106 patients with a monofocal IOL. It was also tested in a subgroup of 38 patients who had bilateral implantation of a diffractive bifocal IOL. Contrast sensitivity was tested using the Vision Contrast Test System (VCTS). Results: In patients with a best corrected visual acuity (BCVA) of 1.0 or better, the CS at all spatial frequencies (1.5 to 18 cycles/degree), both at distance and near, was slightly lower in the bifocal IOL group than in the monofocal group. Mean values were within the normal range. In patients with a BCVA of less than 1.0, the CS was lower and the difference between the bifocal and monofocal groups was less. In patients with bilateral bifocal IOLs, CS was better when tested bilaterally than when testing the better eye alone. Pupil size affected the results to a small degree. Contrast sensitivity appeared to improve over time after implantation of a diffractive bifocal IOL. Conclusions: In patients with cataract and no other eye pathology, the diffractive bifocal IOL will slightly reduce the CS at all spatial frequencies. In those with reduced visual acuity after cataract surgery, CS will be reduced accordingly. In this situation, the reduction from the diffractive bifocal optic would be minor.