Postoperative scenario tracks potential complications.
When and how does incision-related Descemet membrane detachment (DMD) occur during cataract surgery? As a comanaging medical optometrist, how can you successfully comanage this and counsel your patient through recovery?
An 80-year-old man presented with progressive vision loss secondary to bilateral, dense nuclear cataracts. He elected to proceed with a phacoemulsification cataract extraction. While surgery in the left eye was uneventful, the right cataract density required high amounts of phaco energy to disassemble the nucleus.
During irrigation and aspiration, as the aspiration port was inserted through the corneal incision, a 2-mm central tear was noted in the Descemet membrane (DM). A posterior intraocular lens (IOL) was implanted, and he was treated with an air injection into the anterior chamber through a corneal limbal paracentesis track.
At the 1-day postoperative visit, the patient presented with significant corneal edema, deep endothelial folds, visual acuity (VA) of counting fingers at 3 feet, and an elevated intraocular pressure (IOP) of 55 mm Hg.
Centrally, DM was separated from the posterior corneal stroma by approximately 1/4th the corneal thickness at the most severe parts. The anterior chamber air tamponade bubble adhered to the tear of DM and was positioned in the superior anterior chamber, as expected.
Given the patient’s IOP, we performed serial tonometry with topical IOP-lowering drops and an oral carbonic anhydrase inhibitor over the course of an hour and a half. The patient was released with a β-blocker/carbonic anhydrase inhibitor combination drop dosed twice a day. He was also instructed to follow the postsurgical drop regimen of a topical steroid, nonsteroidal anti-inflammatory drug, as well as an antibiotic.
Two days later, the IOP stabilized at 8 mm Hg. He stopped the topical IOP-lowering drops and continued treatment with the postsurgical drop regimen, previously mentioned.
By the 1-week postoperative visit, the air bubble had dissolved, although there were persistent corneal edema and endothelial folds. VA remained at counting fingers at 3 feet. Pachymetry measured a corneal thickness of 694 µm.
Figure 1: At the 3-week postoperative visit, cornal cross section imaging via optical coherence tomography revealed sufficient reattachment and a persistently edematous cornea. The patient continued a treatment course of topical steroids.
Over the next month, we observed the separation of the DMD decrease with each subsequent postoperative visit. Considering the small area of DMD and the observed improvements, we decided to continue conservative treatment rather than a second surgical intervention (see Figure 1).
He continued an extended therapy of topical steroids, with added instructions of sodium chloride hypertonicity ophthalmic (Muro 128) 5% solution (Bausch + Lomb) 4 times a day through the second and third postoperative month, to address persistent but improving 2+ corneal edema and endothelial folds.
VA and central corneal thickness gradually improved to 20/40 and 590 µm, and the DMD totally regressed 5 months after cataract surgery. Mild scarring remained.
The final VA of this patient was 20/40 (as compared to the initial preoperative VA of 20/150). No recurrent DMD was observed during the postoperative period, although a notable episode of rebound iritis coincided with an initial steroid taper
Incision-related DMD is a rare but not uncommon complication of cataract surgery. Surgical trauma is the predisposing factor to these cases.
Incidents occur during surgery from instrumental friction at the incision site, improper incisions (e.g. excessively anterior or shelved incisions), too tight or too long corneal tunnels, dull blades, engagement of DM during IOL implantation, or misuse of the irrigation/aspiration devices.
The severity of the tear is also associated with the degree of ultrasonic energy and length of time of phacoemulsification—essentially, how thick and dense the cataract is.1-7
Additionally, DMD has been reported as a potential complication after iridectomy, extracapsular cataract extraction, viscocanalostomy, trabeculectomy, iridectomy, penetrating keratoplasty, and cyclodialysis.1-6
In uncomplicated cataract surgery cases, DMD is rare and may have resulted from an underlying endothelium disorder rather than surgical trauma.8
In our case, endothelial dysfunction and bullous keratopathy, thankfully, did not occur. In most cases, the cornea will eventually regain clarity if the remainder of the corneal endothelium stays viable. This is attributed to corneal endothelial cell hypertrophy, migration, redistribution, and repopulation.9
The surgeon may opt for observation initially or perform air tamponade surgery after IOL placement to improve recovery. That decision is determined by the extent of and associated risk factors during each step of surgery.
Figure 2: An example of an anterior chamber air tamponade bubble adhering to the tear of Descemet membrane and positioning in the superior anterior chamber.12
(Images courtesy of Thomas John, MD.)
Literature mostly describes spontaneous resolution of partial or less DM detachment. Medical treatment seems to be adequate in many cases, but as an appropriate additional therapy, surgical intervention options can reattach larger DM detachments.
When the DMD area is large or involves a significant portion of the central cornea, initial or secondary sessions of air tamponade with room air or 20% sulfur hexafluoride gas injections are indicated.
If the air tamponade technique fails to reattach DM, further penetrating keratoplasty or endothelial keratoplasty are suggested to rehabilitate vision and avoid total corneal decompensation (Figure 2).10
With most DMD incidences, it’s important to have close communication with the surgeon to determine the best course of action. Although there’s no significant difference in the final visual outcome of intervention vs observation, surgical intervention typically accelerates recovery duration for the patient.
For DMD with visual axis involvement, if DM is separated from the posterior corneal stroma by greater than or equal to 1 mm, conservative treatment using an extended therapy of topical steroids with close observation proves sufficient.11
For older patients, exceptionally mature cataracts, and/or underlying endothelium conditions preexisting surgery, watch closely for DMD occurrence during and after surgery to ensure an optimal postoperative recovery and visual outcome.