Angle-Supported Intraocular Lenses

40 Angle-Supported Intraocular Lenses

Manus C. Kraff

On November 29, 1949, Sir Harold Ridley implanted the first intraocular lens (IOL) in London, England. In the following years, the first early adapting surgeons and researchers tried to determine the best place in the eye optically to implant, and the best place to support, the IOL. Ridley implanted the first lens in the posterior chamber (PC) (Fig. 40.1).¹^,²

Angle-supported, iris-supported, and later the reemergent PC lenses appeared. The angle was a logical area for support because it simplified the surgical procedure.

Dannheim, Strompelli, Barraquer, and Choyce developed the first angle-supported lenses. The Dannheim, Strompelli, and Barraquer lenses were either poorly designed or poorly manufactured, or of inappropriate material, and they all failed shortly after implantation, requiring explantation in almost all cases (Fig. 40.2).

Peter Choyce working in the United Kingdom persisted through the 1950s, 1960s, and 1970s in developing eight iterations of his angle-supported (anterior chamber [AC]) lens. The United States Food and Drug Administration (FDA) officially approved the Mark VIII (Rayner, Kansas City, MO) in 1981 (Fig. 40.3).

The manufacturing of IOLs began in the United States in the mid-1970s. The initial lenses were poorly manufactured copies of the European Choyce Mark VIII lens, with rough edges and warpage, and complications soon arose, including uveitis, glaucoma, and uveitis-glaucoma-hyphema (UGH) syndrome. The manufacturing techniques improved in the next phase of development (the late 1970s and early 1980s). In an effort to improve the design, tubular haptics were employed. With these new lenses, complications took slightly longer to develop but also included UGH syndrome, because of cocooning of the tubular elements in the angle, producing inflammation.

Fig. 40.1 Queen Elizabeth Knighting Sir Harold Ridley in London, March 2000. (From Steinert RF, ed. Cataract Surgery, 3rd ed. Philadelphia: Saunders, Elsevier; 2010.)

It was Charles Kelman who observed that properly manufactured Choyce lens lacked the UGH complication and determined that a plate haptic in the angle, as Choyce had originally designed it, eliminated the risk of UGH. Kelman, whose primary interest was always the small incision, developed flexible haptics with triangular and quadripedal angle support in the mid-1980s to accommodate these lenses. The Kelman quadripod flexible lens design is still the angle-supported lens implanted today. These lenses are called “new-design” IOLs, even though they are almost 30 years old, and they are still the gold standard (Figs. 40.4, 40.5, 40.6).³^,⁴

Indications for the Use of Angle-Supported Lenses

The current indications for angle-supported (AS) IOLs are as follows:

Primary implantation

a. Rupture of the posterior capsule during cataract surgery with insufficient capsular support for a PC IOL

b. Inadequate capsular support, and the surgeon chooses to use a far less traumatic procedure in the eye than suturing it
Secondary implantation

a.After a current or previous intracapsular cataract extraction

b.As an alternative to sutured, glued, or iris-supported PC IOLs.

c.After removal of a subluxated PC IOL with insufficient capsular support remaining

Suturing of a PC IOL, currently being performed when inadequate capsular support exists for the implantation of a PC IOL, may be a traumatic and lengthy process. Unless the surgeon has performed this procedure many times, suturing the lens may subject the eye to avoidable trauma. An angle-supported lens may be a better choice for both the patient and the surgeon, especially in elderly patients, for the following reasons:

An AS IOL is technically more straightforward to implant.
Less surgical time is required for the procedure.
The implantation of an AS IOL is less traumatic to the eye than is suturing of a PC IOL.
If it becomes necessary, the AS lens is easier to remove than a sutured PC IOL.
An AS lens is in contact with the anterior surface of the iris. This cell layer is derived from mesodermal tissue. This is in contrast to a sutured PC IOL that is in contact with the iris pigment layer. This layer is derived from neural ectoderm, which causes intensified intraocular inflammation and cystoid macular edema in the post-surgical period. Additionally, there is the possibility of a greater incidence of late hemorrhaging into the AC and PC.
In a review of my own data from more than 1,500 AS IOLs over a 25-year period, the results are superior to those with sutured PC IOLs.