Evaluation of the dual staining technique for complete removal of idiopathic epimacular membranes

Abstract

Purpose This study tries to evaluate the usefulness of the dual staining first with Triamcinolone acetonide (TA) to effectively visualize and remove the fibrous component of idiopathic epimacular membrane (EMM) and then with brilliant blue G (BBG) to selectively remove the internal limiting membrane (ILM). The primary outcome was the visual acuity improvement and the concomitant decrease in the central macular thickness (CMT) after surgery, and the secondary outcome was the condition of the ILM after this dual staining. Subjects and Methods A prospective, non-randomized, observational cohort study including 15 eyes .The inclusion criterion was a clinically detectable idiopathic EMM diagnosed by fundus examination or optical coherence tomography (OCT), causing a decrease of visual acuity. The exclusion criteria included prior intravitreal injection of TA or antivascular endothelial growth factor, ocular inflammation or prior trauma. During a standard 23 G vitrectomy, peeling the EMM was carried out after administration of TA, BBG (0.25 mg /mL) was injected onto the retinal surface utilizing the ′′dry method′′ or the ′′air-filled technique′′. Both stains will be completely washed out immediately. Then the surgeon recorded the characteristics of the underlying ILM before peeling. Postoperatively the patients were followed up at 1 day, 1 week, 1 month and at 6 months. Primary and secondary outcomes were recorded. Results Our patients included 8 (53.3%) females and 7 males (46.7%). A single surgeon performed all surgeries. TA was used to identify the posterior hyaloid in all 14 cases (93.3%) with no prior vitreous surgery and to effectively visualize and remove the idiopathic EMM in all 15 cases. Three (20%) of the cases had EMM remnants after BBG staining. When this dye was used to stain the ILM during surgery, the unstained EMM clearly stood out against the ILM, which was stained blue. After EMM peeling, all of the eyes had residual ILM except one (6.3%). In all eyes, the surgeon was unable to determine the status of the ILM before BBG staining. The ILM was present and damaged in 8 eyes (53.3%), while it was present and undamaged in 6 (40%). The mean preoperative CMT in eyes were the ILM was found to be damaged on table was 565.3 ± 79.9 μm, while the mean preoperative CMT in eyes were the ILM was undamaged was 446.6 ± 34.4 microns, this was statistically significant (P = 0.005). At 6 months, decimal BCVA improved from 0.18 ± 0.06 at baseline to 0.53 ± 0.11 (P = 0.005). Again at 6 months, the CMT also improved from 506.2 ± 90.03 ΅m at baseline to 365.8 ± 53.3 μm (P < 0.001) but none of the cases had a normal foveal contour. Conclusions In conclusion, dual staining starting with TA effectively led to adequate visualization and removal of the posterior hyaloid as well as the fibrous component of the idiopathic EMM. The subsequent BBG administration in an air filled vitreous (the dry technique) helped selective removal of the ILM with no deleterious effects on the functional or the anatomical outcomes of the procedure as demonstrated by the significant improvement in both the BCVA and the CMT 6 months after surgery.

Keywords

• Triamcinolone acetonide (TA)
• Epimacular membrane (EMM)
• Brilliant blue G (BBG)
• Internal limiting membrane (ILM).