Factors Associated with Development of Dissociated Optic Nerve Fiber Layer (DONFL) Appearance in the PIONEER Study

Abstract

Purpose : The cause of the Dissociated Optic Nerve Fiber Layer (DONFL) appearance after membrane peeling for vitreomacular interface (VMI) disorders remains unknown. We used intraoperative OCT (iOCT) to examine the relationship between retinal alterations during membrane peeling and postoperative development of DONFL appearance.

Methods : This was a post-hoc analaysis of eyes undergoing membrane peeling for VMI disorders in the PIONEER study, an IRB-approved prospective study examining iOCT in ophthalmic surgery. A microscope mounted SD-OCT probe (Bioptigen) was used to obtain pre-incision and post-peel iOCT images. Exclusion criteria included lack of follow-up OCT from 3-12 months postoperatively and poor iOCT or postoperative OCT image quality. iOCT images were assessed for microarchitectural changes including inner, middle, and outer retinal thickness. Clinical variables assessed included indication for surgery and membrane peeling technique (e.g., diamond-dusted membrane scraper [DDMS], forceps). Primary outcome was development of DONFL appearance on 6 month follow-up SD-OCT.

Results : Ninety-nine eyes were included in the study. Preoperative diagnosis included epiretinal membrane (ERM) in 54 eyes (55%), macular hole (MH) in 41 eyes (42%), and vitreomacular traction syndrome (VMT) in 3 eyes (3%). The OCT-based prevalence of DONFL appearance at 6 months was 33%. Prevalence of DONFL appearance was 9.3% in eyes with ERM and 63.4% in eyes with MH. In eyes where forceps alone were used for membrane peeling, prevalence of DONFL appearance was 30.4%, while in eyes where DDMS was used, prevalence was 34.6% (p=0.66). Quantitative analysis of iOCT and acute postoperative retinal layer changes identified increased inner retinal layer thickness as a significant factor associated with postoperative development of DONFL appearance (p = 0.02).

Conclusions : Acute increase in inner retinal thickness and MH repair were associated with the development of DONFL appearance after membrane peeling. This suggests that one mechanism in the development of DONFL appearance may be intraoperative trauma to the inner retina as well as with peeling of the internal limiting membrane (e.g., MH repair). Additionally, this study showed no difference in development of DONFL appearance between forceps-only technique and use of DDMS for peel initiation.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

En face SD-OCT of (A) Severe DONFL and (B) no DONFL appearance.