ULTRASTRUCTURE AND RETINAL IMAGING OF INTERNAL LIMITING MEMBRANE: A Clinicopathologic Correlation of Trypan Blue Stain in Macular Hole Surgery

Vital Dyes in Vitreomacular Surgery

Vital dyes contain complex molecules with chromophores that stain living tissues and have greatly enhanced identification and removal of transparent vitreoretinal tissues during surgery. Several "chromovitrectomy" dyes are frequently used by vitreoretinal specialists, including indocyanine green, trypan blue, brilliant blue G, and triamcinolone acetonide; other dyes are also under investigation. Trypan Blue was approved by the U.S. Food and Drug Administration (FDA) for epiretinal membrane removal, and preservative-free triamcinolone acetonide was approved by the FDA for intraocular use. However, currently available chromovitrectomy dyes have their limitations, and of particular concern for some of them is the possibility for acute and chronic toxicity to the neurosensory retina and retinal pigmented epithelium. The potentially irreversible acute toxicity and other limitations, such as lack of long-term safety profiles, highlight the need for further advancements. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:788-798.].

Brilliant blue G assisted macular surgery: the effect of air infusion on contrast recognisability in internal limiting membrane peeling

BACKGROUND

To evaluate the potential efficacy and safety of inner limiting membrane (ILM) staining with brilliant blue G (BBG) under air infusion.

METHODS

63 patients, treated by one surgeon with macular hole or idiopathic epiretinal membrane were evaluated prospectively. BBG was applied under air infusion in 38 patients (group 1), and injected into the vitreous cavity in 25 (group 2). Main outcome measures were the chromaticity difference between the stained ILM and the unstained underlying retina, anatomical-functional outcomes and complications of the surgery. Chromaticity difference was measured by an objective and quantitative analysis method to describe colour contrast strengths as they are perceived by the human eye. Anatomical and functional outcomes were assessed using optical coherence tomography (OCT), visual field analyses (VFA) and multifocal electroretinography (mfERG).

RESULTS

CIELAB scores showed a significantly superior contrast for group 1 (16.72±2.36) than group 2 (10.34±1.29) (p<0.001). Visual acuity had increased in 28 eyes and remained stable in 10 eyes in group 1. In group 2, visual acuity had improved in 17 patients and remained unchanged in 8 patients. Based on postoperative OCT, anatomical success rate was 100%. During the follow-up period, mfERG and VFA demonstrated no case of BBG toxicity in either group. Cataract progression was the main postoperative complication (six eyes in group 1 and four eyes in group 2) and did not show a significant difference between the groups (p=0.45).

CONCLUSIONS

BBG under air infusion yields a significantly higher contrast staining and easy peeling of ILM associated with anatomical and functional improvement and no retinal toxicity after macular surgery.

Chromovitrectomy and the vitreoretinal interface

It still remains unclear to which extent the presence and the amount of retinal debris seen in internal limiting membrane (ILM) specimens harvested during macular surgery for macular holes or epiretinal membranes are related to the procedure of ILM peeling itself or to modifications of the surgical technique, such as application of vital dyes for visualization of the ILM, or to pathological conditions with epiretinal membrane formation at the vitreoretinal interface. The presence of cellular fragments on the retinal side of the removed ILM appears to be of multifactorial origin, and additional causes besides dye application need to be considered. However, morphological studies with evaluation of vital dyes are still of relevance and provide additional insights into the ultrastructure of the vitreoretinal interface and its interaction with adjuvants used during macular surgery. Chromovitrectomy is an emerging field in vitreoretinal surgery. It is of importance to better understand the tissue-dye interactions, which not only alter the mechanical properties of the tissue being stained, but may also have an impact on the functional result postoperatively.

Dyes for Eyes™: hydrodynamics, biocompatibility and efficacy of 'heavy' (dual) dyes for chromovitrectomy

As epiretinal membranes (ERMs), the internal limiting membrane (ILM) and the vitreous cortex are essentially transparent tissues, or translucent structures, nontraumatic removal may be challenging in various types of macular surgery. Vital dyes stain these thin tissues, thus allowing for better visualization of these structures during vitrectomy and selective 'membrane peeling' from the underlying retina. To avoid swirling of the dye within the fluid-filled vitreous cavity, and to better target the dye onto the macula, a fluid-air exchange is commonly performed. However, this may jeopardize visualization of the macula during peeling due to clouding of the posterior lens capsule, and may lead to postoperative visual field defects. Recently, a new dye solution for staining the ERM and ILM simultaneously has been developed that circumvents the need for fluid-air exchange, i.e. MembraneBlue-Dual™. This paper will focus on the hydrodynamics and biocompatibility of this 'heavy' dual dye and its efficacy for staining of the ILM and/or ERMs during posterior segment surgery in a multicenter clinical setting.

Unanticipated vision loss after pars plana vitrectomy

Although advances in vitreoretinal surgical techniques and technology have helped to minimize the risks associated with surgical manipulation of the retina, retinal pigment epithelium, and optic nerve, unanticipated or unexplained visual loss still occurs. We review causes of vision loss encountered after pars plana vitrectomy, including retinal toxicities, vascular events, and optic neuropathies, and we suggest strategies to limit or prevent them.