An angle-supported phakic intraocular lens (pIOL) remained stable in the anterior segment after pupil dilation, according to a recent study.1Anterior segment optical coherence tomography (AS-OCT) was used to assess IOL positioning and stability before and after pharmacologic pupil dilation three months after surgery.
Anatomic parameters included horizontal pupil size, anterior chamber depth, horizontal angle-to-angle distance, distance between the anterior surface of the IOL and the corneal endothelium at three points, distance between the crystalline lens and the pIOL, and temporal and nasal iridocorneal angles.
"However, to our knowledge, the stability of this pIOL with changes in pupil diameter has not been evaluated," the authors said. "This is relevant given the characteristics of any anterior chamber angle-supported pIOL and the position of this pIOL model in the anterior chamber."
The observational, cross-sectional study included 20 eyes of 20 patients ages 24 years to 48 years presenting with moderate to high myopia. All eyes were implanted with the AcrySof Cachet pIOL.
Study data showed that anterior chamber depth increased a mean 0.06 mm; pupil size, 2.21 mm; temporal iridocorneal angle, 7.75°; and nasal iridocorneal angle, 5.82°. These changes were statistically significant (P < .01).
Changes in distance between the peripheral edges of the IOL and corneal endothelium, and between the crystalline lens and IOL, were statistically insignificant, the authors reported.
"Although there was a slight tendency for the central pIOL to move backward after pharmacologic dilation, the distance between the pIOL edges and the endothelium remained constant," the authors said. "Therefore, sufficient space was maintained between the pIOL and the anterior segment structures after pupil dilation, preventing the possibility of unwanted pIOL contact with ocular structures."
1. J Cataract Refract Surg. 36 (9): 1517-1522 (2010)