New Allergan OptiEdge IOL designed to prevent glare, PCO

The lens optic has a rounded anterior edge to prevent glare and halos and a sharp posterior edge to create a defense against PCO.

Issue: July 1, 2001

ByMichela Cimberle

ROME – The design of the new Allergan Sensar AR40E OptiEdge IOL, with rounded anterior and sharp posterior optic edges, aims for the highest standards for quality of vision and prevention of posterior capsular opacification (PCO), according to a presentation here.

At the 6th Annual Rome Symposium on Cataract, Glaucoma and Refractive Surgery, jointly sponsored by Ocular Surgery News Europe/Asia-Pacific Edition, the International Society of Refractive Surgery and the Associazione Italiana di Chirurgia Cataratta e Refrattiva, Alessandro Franchini, MD, gave a visual demonstration of how the edge design of a lens is a determining factor in the patient’s perception of glare and halos.

“If the sharp-edge design has been demonstrated to create an effective defense against PCO, this is not necessarily true in the prevention of visual disturbances such as glare and halos, which can be very distressing for the patient and even require the explantation of the lens. On the other hand, round-edge IOLs create fewer problems with light refraction, but they don’t have the same barrier effect against cell migration,” Dr. Franchini said.

The optic geometry of the new Allergan lens is conceived to combine both qualities; the sharp angle of the posterior edge limits opacification while the smooth anterior edge prevents glare and other ghosting phenomena.

Comparing light refraction

“In our study, we used a sophisticated ray tracing program to analyze light refraction through a 5-mm pupil using three types of IOL: the square-edge optic Alcon AcrySof MA60BM (figure 1), the round-edge optic Allergan Sensar AR40 (figure 2) and the new OptiEdge AR40E (figure 3),” Dr. Franchini said.

“We placed a light source at 35° from the optical axis to obtain maximum light refraction on the lens, and therefore maximum potential glare. A ghost image forms from the refraction of the light on the optic edge, which is deviated in the opposite direction from the primary image.”

He showed how the square-edge lens produces a ghost image of maximum intensity, where all reflected beams converge in the same, opposite direction (figure 4). Glare and a semicircular or circular halo might be perceived by the patient. With the round-edge lens, there is a higher dispersion of the light. The beams are scattered in all directions (figure 5), and the ghost image is therefore more diffuse and less intense.

“This second lens produces a ghost image 10 times less intense than the primary image, and thus is practically undetected by the patient. This accounts for the absence of glare and halos with this kind of implant,” Dr. Franchini said.

The OptiEdge lens creates an intermediate situation. All the light beams are deviated in the same direction but more diffusely than with the sharp-edge lens (figure 6).

“Ghost intensity is three times lower than that of the square-edge lens and three times higher than that of the round-edge lens. There is a good chance that this intensity of glare remains below the threshold of perception,” Dr. Franchini noted. Clinical results are needed to confirm this supposition since, as the surgeon reported, the first patients had been implanted with this lens only a few days before the Rome meeting.

“If the new lens can prevent glare and halos,” he concluded, “we will have finally achieved the best of both worlds: preventing posterior capsular opacification and guaranteeing the best quality of vision in our pseudophakic patients.”

Figures 1a and 1 b: The sharp-edge AcrySof MA60BM from Alcon shown from two different views.
Figure 2: The round-edge Sensar AR40 from Allergan.	Figure 3: The OptiEdge AR40E from Allergan.
Figure 4: Ghost image of the AcrySof MA60BM.	Figure 5: Ghost image of the Sensar AR40.

Figure 6: Ghost image of the OptiEdge AR40E.

For Your Information:

Alessandro Franchini, MD, can be reached at Istituto di Oculistica, Università di Firenze, Viale Morgagni 85, 50134 Firenze, Italy; +(39) 055-411-765; fax: +(39) 055-437-7749; e-mail: oculist@unifi.it. Dr. Franchini has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Allergan can be reached at 2525 Dupont Drive, Irvine, CA 92612; (800) 433-8871; fax: (714) 246-5913; web site: www.allergan.com.