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A review of 21 cases of the medallion circular loop metal-clip lens
a review of 21 cases of the medallion circular loop metal-clip lens Harry F. Brown, M.D. Newport Beach, California
This report concerns intraocular lens implantation of the Medallion Circular Loop, metal clip lenses. It wilIshare the author's experience with the use of this particular intraocular lens, for those eye surgeons who might be considering using it, or a lens of similar design. Twenty-one cases were reviewed for this summary. The Circular Loop lens has been recommended for lens implantation since the eye surgeon does not have to vary his customary cataract techniques when adding this new procedure. Technique: The method advocated by Medical Workshop was followed initially. With experience in use of the lens, certain modifications were made and certain items were found to be of particular importance, as follows: 1. Insertion It was found that this lens could be inserted easier if the pupil were smaller, (rather than be dilated as recommended). No pre-operative dilation of the pupil is made. After cataract extraction, miochol is inserted to constrict the pupil, and the anterior chamber is then filled with balanced salt solution. With a taut iris sphincter to press against, it is easy to insert the lens under direct visualization, using the mIcroscope. 2. Iridectomy The peripheral iridectomy should be placed exactly at twelve o'clock. After the corneal incision, a suture is placed at twelve o'clock for identification. Using the Vaness scissors, the iris is cut at twelve o'clock as an iridotomy, and this opening is extended parallel to the limbus (rather than V-shaped). This allows a good support, of about 2/3 the radius of the iris, for the metal clip, which fixates the lens through the peripheral iridotomy. 3. Positioning If any positioning of the lens is necessary after insertion, it is easily moved by using a spatula placed against one of the two holes in the upper haptic portion. Thus, centering can be easily performed.
dislocate, it seemed that this was the "ideal lens." However, with further experience, the special problems associated with this implant became evident: 1. Post-operatively five cases occurred in which the nasal or temporal posterior rim had advanced into the anterior chamber. Four were solved by simple dilation of the pupil in the office allowing the posterior rim to return to the posterior chamber, and then constricting the pupil. In one case, all methods failed after repeated attempts. The lens had to be mechanically repositioned, using a spatula in the anterior chamber. Then the pupil was constricted by Miostat irrigation. 2. Three patients noted extreme amounts of glare. Complaints of light reflection are frequent. It became evident that the implant even when perfectly positioned in the eye has a "rotary-type movement" in which the metallic clip through the iridectomy acts as the stabilizing hinge. 3. Two cases of cystoid macular edema developed in patients who had 20/40 vision three weeks post-op, with a subsequent decrease at eight weeks to 201200. 4. Final visual acuity in patients with no retinal pathology was usually 20/30 to 20/40. Even though the distance acuity was lower than that obtained from an ordinary intracapsular cataract extraction, the patients were happier with the quality of vision associated with the implant (true in general with all types of implants). 5. Transient complications (one hyphema, two corneal edema, and two iritis). All were minor problems and cleared with no residual effects. Comments: It should be stressed that the presence of this lens does seem to function to keep the vitreous face within the posterior chamber. In no case did the anterior vitreous project through the pupil, as is common following an ordinary cataract extraction. To date, there have been no cases of corneal dystrophy. The two holes in the haptic portion of the implant are important design-wise. As previously mentioned they are an aid for the surgeon in positioning the lens in the anterior chamber. A summary of the Advantages and Disadvantages of this lens is as follows: Advantages:
Complications: Because the first few lenses were easily inserted and the lens was thought to be very difficult to 182
1. The implant is relatively easy to insert. 2. It is used with an intracapsular cataract
extraction. This eliminates lthe problems of extracapsular extraction, with retained cortex and secondary discission. It allows the eye surgeon to use his usual type of cataract surgery. 3. Quality of vision is good. The patient is able to use both eyes together soon after surgery and has normal peripheral vision. 4. The implant acts to retain the vitreous within the posterior chamber. 5. Lens dislocations are not difficult to correct. Disadvantages: 1. The implant should be accurately centered at the twelve o'clock position, or the lens will not remain centered. 2. A 170 incision is necessary at surgery. 3. There is an extra amount of glare from the lens, because of its rotary movement. It is frequently necessary to use tinted, or ultraviolet filtered type glasses. 4. Lens dislocation does occur post-operatively. 5. The lens is somewhat large and bulky. 0
Comment: It is this author's opinion that the rotary movement of the implant produces iridodonesis, and this is the main disadvantage of this lens. It is the chief cause of the lens dislocations and the glare symptoms may be the cause of the cystoid macular edema.
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This report concerns intraocular lens implantation of the Medallion Circular Loop, metal clip lenses. It wilIshare the author's experience with the use of this particular intraocular lens, for those eye surgeons who might be considering using it, or a lens of similar design. Twenty-one cases were reviewed for this summary. The Circular Loop lens has been recommended for lens implantation since the eye surgeon does not have to vary his customary cataract techniques when adding this new procedure. Technique: The method advocated by Medical Workshop was followed initially. With experience in use of the lens, certain modifications were made and certain items were found to be of particular importance, as follows: 1. Insertion It was found that this lens could be inserted easier if the pupil were smaller, (rather than be dilated as recommended). No pre-operative dilation of the pupil is made. After cataract extraction, miochol is inserted to constrict the pupil, and the anterior chamber is then filled with balanced salt solution. With a taut iris sphincter to press against, it is easy to insert the lens under direct visualization, using the mIcroscope. 2. Iridectomy The peripheral iridectomy should be placed exactly at twelve o'clock. After the corneal incision, a suture is placed at twelve o'clock for identification. Using the Vaness scissors, the iris is cut at twelve o'clock as an iridotomy, and this opening is extended parallel to the limbus (rather than V-shaped). This allows a good support, of about 2/3 the radius of the iris, for the metal clip, which fixates the lens through the peripheral iridotomy. 3. Positioning If any positioning of the lens is necessary after insertion, it is easily moved by using a spatula placed against one of the two holes in the upper haptic portion. Thus, centering can be easily performed.
dislocate, it seemed that this was the "ideal lens." However, with further experience, the special problems associated with this implant became evident: 1. Post-operatively five cases occurred in which the nasal or temporal posterior rim had advanced into the anterior chamber. Four were solved by simple dilation of the pupil in the office allowing the posterior rim to return to the posterior chamber, and then constricting the pupil. In one case, all methods failed after repeated attempts. The lens had to be mechanically repositioned, using a spatula in the anterior chamber. Then the pupil was constricted by Miostat irrigation. 2. Three patients noted extreme amounts of glare. Complaints of light reflection are frequent. It became evident that the implant even when perfectly positioned in the eye has a "rotary-type movement" in which the metallic clip through the iridectomy acts as the stabilizing hinge. 3. Two cases of cystoid macular edema developed in patients who had 20/40 vision three weeks post-op, with a subsequent decrease at eight weeks to 201200. 4. Final visual acuity in patients with no retinal pathology was usually 20/30 to 20/40. Even though the distance acuity was lower than that obtained from an ordinary intracapsular cataract extraction, the patients were happier with the quality of vision associated with the implant (true in general with all types of implants). 5. Transient complications (one hyphema, two corneal edema, and two iritis). All were minor problems and cleared with no residual effects. Comments: It should be stressed that the presence of this lens does seem to function to keep the vitreous face within the posterior chamber. In no case did the anterior vitreous project through the pupil, as is common following an ordinary cataract extraction. To date, there have been no cases of corneal dystrophy. The two holes in the haptic portion of the implant are important design-wise. As previously mentioned they are an aid for the surgeon in positioning the lens in the anterior chamber. A summary of the Advantages and Disadvantages of this lens is as follows: Advantages:
Complications: Because the first few lenses were easily inserted and the lens was thought to be very difficult to 182
1. The implant is relatively easy to insert. 2. It is used with an intracapsular cataract
extraction. This eliminates lthe problems of extracapsular extraction, with retained cortex and secondary discission. It allows the eye surgeon to use his usual type of cataract surgery. 3. Quality of vision is good. The patient is able to use both eyes together soon after surgery and has normal peripheral vision. 4. The implant acts to retain the vitreous within the posterior chamber. 5. Lens dislocations are not difficult to correct. Disadvantages: 1. The implant should be accurately centered at the twelve o'clock position, or the lens will not remain centered. 2. A 170 incision is necessary at surgery. 3. There is an extra amount of glare from the lens, because of its rotary movement. It is frequently necessary to use tinted, or ultraviolet filtered type glasses. 4. Lens dislocation does occur post-operatively. 5. The lens is somewhat large and bulky. 0
Comment: It is this author's opinion that the rotary movement of the implant produces iridodonesis, and this is the main disadvantage of this lens. It is the chief cause of the lens dislocations and the glare symptoms may be the cause of the cystoid macular edema.
183