I have noticed there is often a microcystic edema around the corneal incision in my clear cornea cataract patients. Is this normal?
Microcystic edema over the wound site and over the paracentesis site in clear cornea cataract surgery is not at all uncommon, says Howell M. Findley, O.D., director of Commonwealth Eye Surgery Center in Nicholasville, Ky. More surgeons today are performing clear corneal incisions. Because many are also using a temporal corneal approach, incidents of microcystic edema also occur more often than previously. This finding is so common and localized to the incision site that the surgeon may have passed it off as normal and recorded a clear cornea, Dr. Findley says.
Patients who had dense nuclear sclerosis or Fuchs endothelial dystrophy prior to surgery may require longer phacoemulsification times during surgery, putting them at greater risk for developing a generalized microcystic edema.
Microcystic edema may be seen in near-clear corneal incisions as well. These incisions start just outside the limbus and then turn into clear cornea, Dr. Findley says. These types of incisions often heal a little faster than clear corneal incisions and have a lesser incidence of endophthalmitis.
When can I expect this to resolve, and how should I manage it?
These types of microcystic edema are almost always benign, are not visually significant and resolve without treatment 1-3 weeks post-op.
Microcystic edema over a larger area of the cornea is a different concern, however. Dr. Findley advises you rule out the possibility of elevated intraocular pressure, a common finding postoperatively. Pressures under 40mm Hg probably would not cause microcystic edema, he says. If the pressure is elevated, it should be addressed immediately.
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| Corneal edema may be caused by detachment of Descemets membrane. |
Persistent corneal edema not due to any of the previously mentioned causes may be secondary to retained lens material or detachment of Descemets membrane (DMD). There is evidence that iris retractors may increase the risk of DMD because the iris is more anterior to the cornea.1
Researchers at the University of Illinois in Chicago found that an abnormality in the fibrillary stromal attachment to Descemets membrane could be a predisposition to detachment.2 Other factors that may predispose patients to DMD are a preoperative diagnosis of glaucoma or a recent episode of corneal edema.3
You can see DMD using close slit lamp observation with an optic section, Dr. Findley says. If you suspect DMD, send the patient back to the surgeon for surgical repair of the membrane as soon as possible. In extensive DMD, early surgical treatment is recommended to achieve good results.1
Some patients do experience spontaneous clearing of the cornea with DMD. French researchers cite a patient with a large, superior DMD curling inward and down into the anterior chamber, limited by a thin blood pigmented line one day post-op.4 Two months later, the patients cornea had cleared and remained clear for 10 years with a visual acuity of 20/20 and an IOP of 14mm Hg.
Dont take the risk, though, that your patient will be in this lucky minority. If you observe DMD, refer him or her back to the surgeon immediately.
1. Pahor D, Gracner B. Surgical repair of Descemets membrane detachment. Coll Antropol 2001;25 Suppl:13-16.
2. Kansal S, Sugar J. Consecutive Descemet membrane detachment after successive phacoemulsification. Cornea 2001 Aug;20(6):670-1.
3. Mahmood MA, Teichmann KD, Tomey KF, al-Rashed D. Detachment of Descemets membrane. J Cataract Refract Surg 1998 Jun;24(6):827-33.
4. Feys J, Mohand-Said M, Nodarian M, Hollard P. Spontaneous clearing of the cornea with detachment of Descemets membrane. J Fr Ophthalmol 2002 May;25(5):502-4.
Vol. No: 139:08Issue:
8/15/02
