What Leads to DMD During Cataract Surgery?

Friction of surgical instruments has the greatest association with incisional Descemet membrane detachment (DMD) during cataract surgery, according to results of a case series published in JAMA Ophthalmology. To help reduce the severity of incisional DMD, researchers suggested decreasing ultrasonic energy and phacoemulsification time.

Incision-related DMD is a common complication in cataract surgery, as previous studies have found incidence of DMD at the incision site 1 day post phacoemulsification ranges between 36.7% to 82%. Although slight incisional DMD can be self-healing, “in the case of inexperienced surgeons or unhealthy corneas, severe DMD may occur, leading to corneal decompensation that requires transplantation,” authors wrote.

To determine the surgical steps during which incisional DMD is most likely to be initiated and to identify potential factors contributing to or reducing risk of DMD, researchers used intraoperative optical coherence tomography (iOCT) technology to detect incisional DMD in real time. Investigators subsequently analyzed associated factors to formulate an evidence base for prevention strategies.

A total of 133 patients undergoing phacoemulsification with intraocular lens (IOL) implantation for age-related cataract were included in the case series. All patients underwent the procedure between January 1 and March 31, 2019, at a single ophthalmologic center in China. For patients undergoing surgery in both eyes, only right eyes were included in the analysis; patients with lens dislocation, glaucoma, or uveitis were excluded.

The mean (SD) patient age was 72.3 (8.1) years, and the majority (n = 77; 57.9%) of participants were female. Of the 133 patients who underwent surgery, DMD occurred in 125 eyes (94%) during capsulorrhexis (2 [1.6%]), hydrodissection (7 [5.6%]), phacoemulsification (69 [55.2%]), irrigation-aspiration (44 [35.2%]), and IOL implantation (3 [2.4%]).

Researchers also found that “the extent of DMD increased during the operation (mean [SD] difference between final and initial relative DMD length, 22.8% [1.4%]; 95% CI, 20.0-25.6; P < .001).” Initial DMD occurred most frequently (n = 77) at the posterior margin of the surgical wound, while at the end of surgery final DMD occurred at the anterior wound margin (n = 6 [4.5%]), posterior wound margin (n = 12 [9.0%]), and both margins (n = 107 [80.4%]).

Multivariate stepwise analyses found the extent of DMD was associated with time of ultrasonography (β = 0.34; 95% CI, 0.17-0.50; P < .001), equivalent mean ultrasonic power (β = 87.8; 95% CI, 19.1-156.4; P = .01), and presence of DMD at the anterior and posterior wound margins (coefficient = 16.7; 95% CI, 6.4-26.9; P = .002).

According to researchers, findings indicate the occurrence and severity of DMD are likely related to intraoperative manipulation of surgical instruments. To prevent DMD caused by mechanical friction, “handpiece types and materials could be optimized…or the construction of the incision could be modified for the enlarged incision mechanically at the end of surgery,” authors wrote.

In addition, “Enlarging the internal size of the incision with the femtosecond laser could increase the scope for movement of the phacoemulsification handpiece and irrigation-aspiration tip without compromising the stability of the incision or increasing surgery-induced astigmatism in the future,” researchers suggested.

Because the study only included patients with age-related cataracts, findings may not be generalizable to all patients undergoing cataract extraction. Wide CIs due to a relatively small sample size also mark a limitation to the study.

Reference

Dai Y, Liu Z, Wang W, et al. Real-time imaging of incision-related descemet membrane detachment during cataract surgery. JAMA Ophthalmol. Published online December 10, 2020. doi:10.1001/jamaophthalmol.2020.5396