The present invention relates generally to laser delivery probes and uses thereof, and more particularly, to a laser probe especially adapted for ophthalmologic applications and its use in treating glaucoma with a filtering procedure.
Glaucoma is a long-term condition where the fluid pressure inside the eye, the intraocular pressure, remains above normal for extended periods of time. This abnormal condition, if not treated properly, can lead to blindness. The high internal fluid pressure tends to cut off needed oxygen from the retina, which, if continued for a time, can cause retina cells to die. A healthy eye allows fluid to pass out through the trabecular meshwork adjacent the iris, and then through the schlemm canal and into the sinuses. Intraocular pressure builds up to unacceptable levels when this passage becomes blocked. Indeed, glaucoma is one of the chief causes of blindness, worldwide.
The current goal in the management of the patient with advanced glaucoma is the reduction and control of this intraocular pressure. Unfortunately, it is often difficult to achieve a desired pressure level in a particular patient by medical therapy because of the complexity of the disease. All too frequently, intraocular pressure continues to increase, or at least remains high, when the patient is being treated for the condition with a maximum level of medication. As a result, other, more invasive alternatives generally must be used.
These invasive alternatives include various surgical techniques of forming an opening into the eye in order to provide a fluid passage that relieves the high intraocular pressure in glaucoma patients. One method involves treatment of the trabecular meshwork with a light beam from an argon laser, without surgery, in an attempt to restore an outflow of fluid through this meshwork. The laser beam is directed through the cornea and against the trabecular meshwork. Current studies, however, have shown that a significant percentage of these procedures fail after some period of time. Other lasers, such as Q-switched ruby and neodymium:YAG have also been used to perform trabeculo-punctures.
Another invasive method involves forming a new pathway through the sclera adjacent the cornea in order to allow aqueous fluid to pass from the anterior chamber of the eye, through the pathway and into a region under the conjunctiva. A flap is first opened in the covering conjunctiva by making straight line incisions along three sides of a rectangle, in a position alongside the cornea. The sclera is exposed by folding back this flap. A small opening is then formed in the sclera by either an incision (external filtration surgery) or a laser light beam. Carbon dioxide, neodymium:YAG in the free running mode, and excimer lasers have been used to perform sclerostomies. After the opening is formed, the conjunctival flap is sewn shut. Neither of these methods, however, have provided a complete solution. Surgical intervention of the conjunctiva can cause complications because of surgical trauma, and the necessary sewing shut of the conjunctival flap. External filtering surgery results in successful lowering of the intraocular pressure in 65% to 85% of the cases, depending on the condition of the eye.
Accordingly, it is a primary object of the present invention to provide an improved sclerostomy procedure and fiber optic probe for use in the procedure that is simpler, more effective and long lasting, and which is less damaging than current procedures.
It is another object of the present invention to provide a procedure and fiber optic probe for use in the procedure that can be performed on an outpatient basis, in an office, clinic or hospital.