Contrast sensitivity after extracapsular and intracapsular cataract extraction.

Contrast sensitivity function after cataract extraction and intraocular lens implantation has been mainly correlated to the type or the material of the intraocular lens. Our purpose was to identify other possible factors, like posterior capsule, to contrast sensitivity alterations after cataract surgery, comparing patients operated for cataract by techniques that mainly differed on the posterior capsule's integrity. The intraocular lens implanted was either a posterior or an anterior chamber one, always monofocal and made of PMMA. We measured contrast sensitivity function at four spatial frequencies in two groups of operated individuals (group A and B) and in one group of healthy control individuals. Each group consisted of 42 eyes. Group A comprised eyes with intact, clear posterior capsule and posterior chamber monofocal intraocular lens. Group B comprised eyes with ruptured or removed posterior capsule and anterior chamber monofocal intraocular lens. Control group comprised healthy control eyes. A pair matched design was used to compare contrast sensitivity values among the individuals of the three groups. No statistically significant differences in contrast sensitivity values were found when group B patients were compared to healthy controls (p >0.05). Patients of group A exhibited contrast sensitivity function impairment at intermediate and high spatial frequencies when compared to patients of group B (p <0.05) and to controls (p <0.01). It seems that intact posterior capsule provides inferior visual function, in spite of relatively good visual acuity and apparently satisfactory results.