Inverted Meniscus Intraocular Lenses Can Prevent Negative Dysphotopsias
Published 2024
- 42nd Congress of the ESCRS
Reference: FP27.07
| Type: Free paper
| DOI:
10.82333/w1db-fw69
Authors:
Harilaos Ginis* 1
, Dimitrios Christaras 1
, Spyridon Tsoukalas 1
, José María Marín 2
, Pablo Artal 3
1diestia,Athens,Greece, 2Oftalvist,Murcia,Spain, 3Laboratorio de Optica,Universidad de Murcia,Murcia,Spain
Purpose
Negative dysphotopsia (ND) is an entoptic phenomenon appearing in pseudophakic eyes, causing a crescent-shaped shadow in peripheral vision. It arises from light passing unfocused through the gap between the intraocular lens (IOL) and the iris. This study used a physical model of the pseudophakic eye to compare ND occurrence and severity between biconvex and meniscus intraocular lenses for different pupil diameters and Anterior Chamber Depth (ACD).
Setting
Laboratory testing, Diestia Systems, Athens Greece
Methods
The water-filled eye model had a PMMA cornea with a radius of 7.73mm (Q= -0.24) and an iris at 3.55mm from the anterior surface of the cornea. The IOL was positioned at 0.5 or 1.5mm from the pupil (ACD of 4.05 and 5.05mm respectively). Images of a horizontal bar (5x15 degrees) at the peripheral visual field were recorded at the retinal plane using a camera. ND was quantified by comparing the retinal illuminance of regions within the dark band against adjacent areas (A ratio ranging from 0 (completely dark band) to 1 (no dark band). Two types of IOLs, a biconvex Acrysof SA60AT (Alcon, TX, USA) and an inverted meniscus ArtIOL Art25 (Voptica SL, Murcia, Spain) were tested at the different ACD and pupil diameter conditions. (3 and 6 mm).
Results
A characteristic shadow manifested on the retinal image at a visual angle of approximately 75 degrees for the biconvex IOL, becoming more pronounced at a smaller pupil diameter (3 mm) compared to a larger one (6 mm) and the greater ACD. On the contrary, the meniscus-shaped IOLs did not produce the shadow at any of the tested pupil diameters. ND ranged from 0.65 to 1 in the tested conditions.
Conclusions
The incidence of negative dysphotopsia is diminished or entirely avoided by employing meniscus-shaped intraocular lenses (IOLs). This conclusion aligns with results from non-sequential ray-tracing modeling. The meniscus configuration, due to its design, presents a reduced peripheral gap between the IOL's optic edge and the posterior surface of the iris at a specific implantation depth. Consequently, this characteristic makes it inherently less prone to inducing negative dysphotopsia.