Contrast sensitivity in multifocal intraocular lenses

Abstract

Contrast sensitivity was measured in two groups of 20 patients each implanted with refractive and diffractive multifocal intraocular lenses and in two control groups of 20 patients each--the first group implanted with a monofocal IOL and the second phakic subjects. All cases had a postoperative follow-up of at least one year and a corrected visual acuity of 20/20- or better. We used two psychophysical tests, Pelli Robson test chart and Vistech 6500 test chart, and an objective test, visual evoked potentials (VEPs). There were no statistically significant differences in contrast sensitivity in the psychophysical tests between the two groups implanted with multifocal IOLs. The situation was different, however, when they were compared with the control group with monofocal IOLs and the group with phakic eyes: the Pelli-Robson test results were not significantly different, but the Vistech 6500 test showed a significant reduction in contrast sensitivity in both groups. The pattern VEPs objective test confirmed these results: no differences were noted between the two different multifocal IOLs, while there was a drop in contrast sensitivity when their results were compared with those of the control groups; the intermediate frequencies were particularly affected by this phenomenon. The contrast sensitivity in patients with multifocal IOLs is reduced despite high visual acuity and this can affect the quality of vision.

Visual acuity from far to near and contrast sensitivity in eyes with a diffractive multifocal intraocular lens with a low addition power

“…We used the CAT-2000 for contrast sensitivity testing because with and without glare, it is more sensitive than other contrast sensitivity testing devices. 11,12 Many studies [13][14][15][16][17][18][19][20][21] report that contrast sensitivity is impaired with most multifocal IOLs, especially diffractive IOLs. However, because the multifocal IOL we used has an aspheric optic and a low add power, contrast sensitivity with and without glare under photopic and mesopic conditions was markedly better than with the C4.0 D IOLs we tested in the clinical trial.…”

“…Second, contrast sensitivity tends to be impaired and glare disability greater, in particular with diffractive multifocal IOLs. [13][14][15][16][17][18][19][20][21] Third, halo and glare symptoms are more severe with multifocal IOLs, specifically refractive models. [30][31][32][33] The current study showed that the aspheric diffractive multifocal IOL with low add power improved intermediate visual acuity significantly and provided contrast visual acuity with and without glare similar to that with monofocal IOLs.…”

Avaliação da sensibilidade ao contraste e da estereopsia em pacientes com lente intra-ocular multifocal

“…Porém, alguns estudos envolvendo LIOs multifocais, mostram resultados de SC consideravelmente diferentes (11)(12)(13)(14)(15)(16)(17)(18) ; entretanto deve-se ter cuidado com comparações, devido às diferenças entre pacientes, tabelas, condições de iluminação e examinadores.…”

Phakic intraocular contact lenses–perversion of a profession?

“…The list of IOCL complications is long and also includes some less than sight threatening events such as pupillary distortion and/or retraction (Waring, 1998), poor IOCL ®xation with consequent reopening of the globe (Menezo et al, 1998;Waring, 1998), incorrect lens power (Menezo et al, 1998), and a reduction in contrast sensitivity in multifocal implants (Ravalico et al, 1993).…”