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Pre-op images of a 19-year-old male who was injured in a pyrotechnic explosion. He had a white cataract with a fibrotic anterior capsule, an irregular inferior lens border suggestive of zonular weakness, and a complete iridodialysis inferiorly with evidence of iris atrophic changes
 Post-op image after iris repair (pre- and post-dilation). The patient is 20/20 and the pupil has rounded out. Source (all): Steven G. Safran, M.D.
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After many consultations, family decides on
procedure that's best
for explosion victim
When a 19-year-old male whose eye was injured in a fireworks accident presented to Steven G. Safran, M.D., Lawrenceville, N.J., he was faced with a decision—repair the damaged iris or replace it altogether with a prosthesis. The patient and his mother had been to several surgeons and their hopes were dimming.
"The mother contacted me after bringing [the patient] to various surgeons/institutions and hearing a poor prognosis for visual and functional recovery of the iris, which left her somewhat dismayed," Dr. Safran said.
The young man had a white cataract with a fibrotic anterior capsule, an irregular inferior lens border suggestive of zonular weakness, and a complete iridodialysis inferiorly with evidence of iris atrophic changes.
"I told the mother that I thought I could do a pretty good job of restoring iris anatomy, but they might want to consider an iris prosthesis," Dr. Safran said. "After
discussing the details of the device and the surgery I would do to repair rather than replace the iris, the family decided to have me do the surgery with the belief that this might give a greater amount of iris function than a prosthesis."
Dr. Safran also consulted a number of anterior segment surgeons, including Kenneth Rosenthal, M.D., New York Eye and Ear Infirmary, New York, who has extensive experience with the foldable iris diaphragm from HumanOptics (Erlangen,
Germany) and who is the co-inventor (with Volker Rasch, M.D.) and first surgeon to implant the first modular iris implant.
Dr. Rosenthal agreed that a restoration of the iris anatomy was possible in this case.
"When Dr. Safran first consulted me about this case, I noted that the pupillary ruff and most likely the sphincter muscle were intact, and the primary defects were a probable zonular dehiscence underlying a clean iridodialysis," Dr. Rosenthal said. "I recommended that cataract surgery with possible use of a capsular tension ring (CTR) and a primary repair of the iridodialysis be performed."
Where to begin
It's difficult to create countertraction against the leading edge of a tear when zonular compromise is present. While one approach is to start the rhexis at or near the area of zonular dialysis, Dr. Rosenthal said, "I prefer to perform the rhexis by starting at the side opposite the area of zonular dialysis, and tearing
toward the dialysis, which changes the vector force toward, rather than against, the weakened area. Sometimes it is necessary to begin the rhexis counterclockwise, up to and within the area of the weakness, and then continue the rhexis from the opposite side, tearing, for example, clockwise, until the leading edges of the rhexes meet, again lessening capsular tension."
In cases of zonular compromise, the need for additional capsule support is essential.
"My preferred method is to support the capsule from within by either insufflating the capsule with a generous amount of a highly retentive viscoelastic such as Healon 5 (Abbott Medical Optics, AMO, Santa Ana, Calif.), which will maintain tension within the capsule locally, or by early placement of a CTR with or without a Cionni ring modification, or an Ahmed segment, to buttress the capsule's support within the bag," Dr. Rosenthal said. "I often use these two modalities together to
create a strong support system in the absence of intact zonules."
Capsular hooks, which may be needed with diffuse or profound zonular deficiency, can cause a tear in the edge of the capsule or an inadvertent radialization of the rhexis, Dr. Rosenthal added, although several new modified designs (such as those manufactured by MicroSurgical Technology, Redmond, Wash.) may be useful with less risk of capsular damage. He uses an intraocular endoscope (endocyclophotocoagulation unit, Endo Optiks, Little Silver, N.J.) while suturing to the ciliary sulcus or iris root. The unit allows him to see exactly where the sutures should be placed and place them there without damaging the ciliary body.
"I use a combination of direct visualization of the placement of the suture needle, coupled with transillumination of the sclera ab interno from the coaxial illumination of the probe, to assess the scleral wall
position of the ab externo suture," Dr. Rosenthal said.
The importance of
instrumentation
The use of capsular dye in performing iris repair is vital to its outcome as is the judicious use of capsular microforceps and scissors, Dr.
Rosenthal stressed. "For those not willing to outlay the cost of the beautifully constructed instruments by MST, disposable, single-use
vitreoretinal scissors and forceps are available from Alcon [Fort Worth, Texas] and Grieshaber [Alcon, Schaffhausen, Switzerland].
In this case, Dr. Safran did use VisionBlue (trypan blue, Dutch
Ophthalmic, Exeter, N.H.), which ended up staining the vitreous.
"It did not ruin the case, but made the surgery far more difficult," he said. Dr. Rosenthal's solution: "To avoid VisionBlue from migrating behind the capsule, obscuring the red reflex, retentive viscoelastic (either dispersive such as Healon EndoCoat [AMO] or Viscoat [Alcon], or pseudodispersive such as Healon 5) can be placed at the peripheral capsule to serve as a barrier." An added benefit of Healon 5 is that it may assist in the capsulorhexis by providing countertractional tamponade of the anterior capsular surface.
Dr. Safran also used iris retractors to help tear the capsule and hold the iris out of the way and in place while he performed other parts of the surgery.
How it ended
Many times an iris repair may end up disappointing for the patient. Because of this elegantly performed surgery, this was not one of those cases, Dr. Rosenthal said. "While I have had extensive
experience with implantation of
various types of iris prostheses, I agree with Dr. Safran's decision to perform the primary repair here, since the pupil will still dilate (and would be of a fixed diameter with an iris prosthesis) and since the use of the iris prosthesis would add expense without significant clinical
advantage," he said. "Nonetheless, I have performed many iris prosthetic implants in cases in which there is extensive iris damage, and particularly in cases of sphincter damage, fixed dilated pupils, multiple or
extensive iridodialysis, or significant transillumination defects. In such cases, a primary repair is disappointing more often than not."
This patient ended up being 20/30 uncorrected and 20/20 with about 1 D of with-the-rule astigmatism. Dr. Safran saw him recently, and he's currently 20/20.
"The pupil has rounded out even more, providing better function and cosmesis," Dr. Safran said. "He is very happy with the cosmetic outcome and has very good pupil function."
Editors' note: Dr. Safran has no financial interests related to this article.
Dr. Rosenthal has financial interests with HumanOptics.
Contact information
Rosenthal: kr@eyesurgery.org
Safran: safran12@comcast.net |
