In the past, conventional means to evaluate patients' near visual acuity consisted of letters or numbers on a near card. A person's ability to distinguish the near card's figures may have no bearing, however, on his capacity to read functionally.
A study presented at the 2007 American Academy of Ophthalmology's Annual Meeting in New Orleans evaluated functional near vision in patients with multifocal IOLs using the NPReading Test.1 The test, developed with the collaboration of The Post and Courier of Charleston, South Carolina, is a practical examination system designed to simultaneously determine reading acuity, reading speed, and functional vision.
In the study, 56 patients were enrolled and divided into four groups. Group one (n=15) had received the AcrySof Restor lens (Alcon Laboratories, Inc., Fort Worth, Texas) in one eye and the ReZoom lens (Advanced Medical Optics, Inc., Santa Ana, California) in their fellow eye. Group two (n=14) received the AcrySof Restor IOL bilaterally; group three (n=15) had blended AcrySof Restor (postoperative target refraction in dominant eye was plano; nondominant eye, 1.00 D); and group four (control; n=12) underwent the implantation of monofocal IOLs with external near correction.
The investigators compared all of the patients' reading speeds in words per minute with different font sizes at 3 months postoperatively.
Those who had received multifocal IOLs and were measured with or without their best distance correction were capable of reading faster than patients in the control group using their best near correction. Patients in groups one, two, and three were able to read faster (193.5, 201.6, and 184.9 words per minute, respectively) than those in group four (118.8 words per minute). The number of subjects able to read in all groups decreased as the font size decreased.
The investigators concluded that the slower reading speed of the monofocal group compared with the multifocal IOL groups indicated that the multifocal lenses provide good functional vision.
