[Visual acuity and contrast sensitivity in pseudophakic patients after cataract surgery]

ABSTRACT

This study was designed to determine the role of intraocular lens implantation in visual acuity and contrast sensitivity in pseudophakic patients. This case control study was done in the year 2004 in Mashhad Ophthalmology Center of Khatam- al- Anbia. with convenience sampling method based on object visual acuity and contrast sensitivity in 85 pseudophakic patients [110 eyes] with a mean age of 63.83, and 20 age - matched phakic subjects [40 eyes] were compared. The visual acuity and contrast sensitivity at distance after correction of refractive disorders were measured by Snellen chart and Cambridge Low Contrast grating chart at 6 meter. Individual data, surgery date, visual acuity, and contrast sensitivity were gathered in a questionnaire and analyzed by descriptive statistics and frequency distribution tables. Statistical test showed that the best corrected visual acuity in IOL group had no significant difference from that in the phakic group [p=0.36]. But the contrast sensitivity reduces in the pseudophakic group comparing with the phakic group [p=0.004]. These patients often complain of blur vision, despite of good visual acuity. Contrast sensitivity reduced significantly with increase of age in both groups of normal and pseudophakic patients. No improvement in contrast sensitivity and visual acuity was found over the time [P[va]=0.174, P[cs]=0.257]. This study showed that intraocular lenses could provide good visual acuity for distance but there was slight reduction in contrast sensitivity. Contrast sensitivity test is an important tool for evaluation of visual function; especially age related changes or intraocular differences, which may not have been detected by visual acuity tests