A. Field of the Invention
The present invention relates to an apparatus and method for implanting intraocular lenses in ophthalmic surgical procedures. More particularly, this invention relates to a means and method for implanting intraocular lenses made from a relatively soft, pliable foldable material through a very small surgical incision.
B. Problems in the Art
Working within the human eye requires that any incision be kept to minimum size. This conflicts with the need to use surgical instruments and tools in performing surgery within the eye, including implanting intraocular lenses.
Microsurgical tools are utilized in eye surgery. As the term "microsurgical" implies, because of the small frame work and intricate nature of surgery on the eye, the microsurgical tools or instruments must at once both have control portions (usually handles) which are easily grippable and maneuverable by the surgeon's hands and fingers, and have working end tips which are down-sized or basically miniaturized. The size and shape of instrument tips can be made so as to give the surgeon grasping, positioning, and retrieval capabilities on a very small scale. Conventional microsurgical forceps, having parallel spaced apart handle and tip combinations, work adequately for many requirements of ophthalmic surgery.
However, in ophthalmic surgery, even conventional microsurgical forceps are many times deficient. Where intrusion is needed to gain access into the interior of the eye, such as with delivering an artificial intraocular lens for implantation, conventional forceps basically require that the surgical incision or wound must be at least as wide as the open width of the forceps tips. This is required to insert and release an object into the eye and retrieve objects from the eye, which necessitates opening and closing of the tips within the eye. In other words, microsurgical forceps, when closed, generally present a fairly narrow and small cross section. They could easily be inserted through a small incision. However, in order to open the forceps tips to perform any grasping or releasing function within the eye, or to allow insertion of an object gripped in the forcep's tips, the incision must be wide enough to accommodate the open position of the tips.
In ophthalmic surgery, smaller wounds or incisions cause less trauma, reduced problems and scarring, and promote faster healing. Many forceps can be inserted through a very narrow wound, but can not be opened up inside the cavity because movement is restricted by the small size of the incision. Further, a narrow incision does not allow insertion of an object wider than the wound.
With conventional microsurgical forceps, therefore, the incision has to be made large enough to provide the needed opening and closing movement of the forceps, and also to accommodate the passage of objects that must be inserted into the cavity.
A specific example in ophthalmic surgery is where an artificial replacement lens (referred to in the art as an "intraocular lens") is to be delivered into the interior cavity of the eye. Such a lens, of course, has a certain length, width and thickness. Generally these lenses are thin in thickness, yet by comparison substantial in length and width; being somewhat rectangular or elliptical in shape. Even grasping the lens on its edges across its width requires a wound approximately as wide as the lens to insert the lens into the eye. In fact, the wound many times must be slightly larger to enable the forceps tips to pass and to allow the forceps tips to release the lens in the eye.
Recent developments in soft intraocular lenses allow that the lens can be folded or rolled into a small, somewhat cylindrical form. With the advent of the use of intraocular lenses made from relatively soft, flexible materials, such as silicone or hydroxyethylmethacrylate, has furthermore come the suggestion that these lenses could be folded or otherwise manipulated to facilitate implantation of the lenses in the eye. Reference is made to the following publications for further background information in this regard: Dreifus, Wichterle, and Lim, of II. Eye Clinic, Charles University, Prague, Czechoslovakia, "INTRACAMERAL LENSES MADE 0F HYDROCOLLOID ACRYLATES", from Cs. oftamologie, 16(2), 454-459 (1960); U.S. Pat. No. 4,664,666 (Barrett); U.S. Pat. No. 4,573,998 (Mazzocco); and U.S. Pat. No. 4,813,957 (McDonald). In this form, the lens can be inserted into the eye through a much smaller incision than would otherwise be required.
The problem then becomes how to fold the lens and retain it undamaged for delivery into the eye, and then release it when inside the eye. The lens must be released slowly, and restrained during release so that it does not pop out of the restraining device.
It would therefore be advantageous to have an apparatus which could pass through a smaller opening and still be able to open and release while inserted through the opening, which would be allowed to be smaller than the width of the forceps tips when in a substantially open position.
It would furthermore be advantageous to develop a method to insert an artificial lens into the eye through as small an opening as possible.
Although the advent of soft intraocular lenses has made it possible to consider folding the lenses to facilitate the use of a smaller surgical incision, there are still significant problems associated with the folding or other manipulation of soft lenses and the implantation of such lenses in the folded or manipulated state. For example, the same properties which allow the lenses to be folded also make the lenses susceptible to being damaged due to contact with folding instruments such as forceps. The damage can be in the form of scratches, tears or other physical damage to the lenses, as well as deterioration of the optical properties of the lenses. In addition, it should be borne in mind that the implantation of intraocular lenses is a very delicate procedure which is performed with the aid of a microscope. The lenses are quite small (i.e., typical diameter of optical portion about 6 millimeters and overall length/width of 12 millimeters), and are therefore difficult to handle under the best of circumstances. The handling of the lenses with conventional surgical instruments, such as forceps, can be much more difficult if attempts are made to fold or otherwise manipulate the lenses.
Present ophthalmic surgical procedures present problems with respect to insertion of soft intraocular lenses through as small of incision as possible along with providing a controlled release and unfolding of a lens once inside the eye. The surgeon must be able to easily and reliably control operation and orientation of the instrument or instruments used in such procedures; but at the same time introduce both the tool or apparatus and the artificial lens through a very small incision; and controll-ably release the lens into the eye.
Accordingly, there is a need for an improved apparatus and method for folding a soft intraocular lenses and releasing the lens for implantation in the eye using a small incision and with minimized risk of damaging the lens or the eye. The present invention is directed to fulfillment of this need.
These and other objects, features, and advantages of the present invention will become more apparent with reference to the accompanying specification and claims.