Brief overview of dye staining
Surgical procedures using vital dyes
- Anterior and posterior/pars plana vitrectomy
- Epiretinal membrane (ERM)/internal limiting membrane (ILM) peel
- Macular hole repair
- Retinal detachment repair
- Evaluate the patency and leakage of glaucoma filtering blebs
- Color pharmacologic agents, such as mitomycin C and 5-fluorouracil, for precise placement.
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A Guide to Vital Dyes for Optometrists
Fluorescein sodium (NaFl) dye
- Healthy cells
- Damaged or dead cells
- Intracellular spaces
- Tear film
Uses for fluorescein sodium dye
- Epithelial defects: The major goal of NaFl staining in the cornea and conjunctiva is to detect epithelial abnormalities and to aid in the diagnosis of ocular surface pathologies such as dry eye disease (DED), erosions, abrasions, and a variety of other disorders.
- Tear film: NaFl staining of the tear film allows evaluation of tear break-up time (TBUT), tear volume and clearance, tear secretion, and tear turnover.
- Ocular biometrics: NaFl is used in Goldmann tonometry to measure intraocular pressure (IOP), and is vital in contact lens fit assessments.
Assessment using fluorescein sodium dye
Pros/cons of NaFl dye
- Pros: NaFl has many advantages, such as its commercial availability, selection of preparation choices, and high patient tolerability. In addition, NaFl is highly fluorescent, with the luminosity of fluorescence proportional to the tear film thickness observed.8
- Cons: One of the biggest drawbacks to NaFl is that it diffuses very quickly, so staining must be read immediately. Another downside is that the fluorescent tear film itself may obscure the staining pattern behind it.8
Rose bengal (RB) dye
Uses for rose bengal dye
- Aqueous tear deficiency
- Corneal and conjunctival neoplasms
- Dendritic herpes simplex corneal ulcers
- Lacrimal and meibomian gland dysfunction
- Nocturnal lagophthalmos
- Sjögren’s syndrome
Assessment using rose bengal dye
Pros/cons of rose bengal dye
- Pros: The RB staining pattern lasts longer than the NaFl staining pattern.8
- When RB is applied as a drop, there is significant stinging, which causes reflex tearing.
- It might be difficult to distinguish RB pigment from the underlying color in patients with injected eyes.6
- RB stains skin on contact, causing visually undesirable discoloration that can last for several hours.
- More importantly, RB is toxic to cells and can also be photoactivated by ultraviolet radiation, causing additional toxicity. As a result, sun exposure will exacerbate any symptoms, particularly in dry eye patients with severe staining.8
Lissamine green dye
Uses for lissamine green dye
Assessment using lissamine green dye
Pros/cons of lissamine green dye
- Pros: Compared with RB, LG is nontoxic and is better tolerated by patients, thus making it a superior dye for the evaluation of the conjunctiva.11
- Cons: Some studies have shown that LG strips may not provide enough concentration to highlight conjunctival staining. Liquid LG (bottled) does deliver acceptable concentrations, however due to formulary rules, this preparation is not available in the US.7
Combination of fluorescein sodium (NaFl) and lissamine green (LG) dye
Uses of NaFL and LG dye
Assessment using NaFl and LG dye
Pros/cons of NaFl and LG dye
- Pros: Combining NaFl and LG simultaneously allows comprehensive staining of the entire ocular surface for uninterrupted evaluation, and increases clinician efficiency.
- Cons: The clinician will need to shift back and forth between white light and the cobalt filter during the examination, adjusting the magnification as necessary to appreciate tiny areas within the larger region. The switching process might seem more cumbersome to some.
Fluorescein sodium (NaFl) dye
Uses for injectable NaFl dye
- Angiography: For years, the injection of intravenous fluorescein sodium has been the gold standard for the diagnostic staining of retinal and choroidal vessels during fluorescein angiography (FA).4
- Cataract surgery: NaFl is used as a coloring agent underneath the capsule in cataract surgery, using blue light to visualize staining of the epithelium located on the inner surface of the anterior capsule.2
- Chromovitrectomy: NaFl is very well absorbed by the vitreous, and gives improved visualization of clear vitreous fibers during chromovitrectomy without toxicity.
Note: Highlighted procedures indicate off-label use.2
Pros/cons of injectable NaFl dye
- Pros: NaFl is available in multiple commercial formulations and is very economical.
- Cons: NaFl may not be an optimal agent for cataract surgery due to the migration of NaFl into the vitreous cavity, staining of the cortex and nucleus lenticular regions, and staining of the corneal endothelium, resulting in decreased contrast between the lens capsule and cortex.2
Contraindications for injectable NaFl dye
Children and infants
Indocyanine green dye
- ICG can penetrate the RPE, macular xanthophyll, and other ocular pigments
- ICG has limited diffusion through the small fenestrations of the choriocapillaris.2
Uses for indocynanine green dye
- Angiography: ICG angiography (ICGA) is particularly useful in analyzing choroidal vasculature and is the gold standard for choroidal retinal angiography. ICG is FDA-approved for IV use only.15
- Cataract surgery: Not only is ICG valuable in staining the anterior capsule without any special illumination, but ICG also allows superior capsule visualization in conditions with poor or no red reflex. In ocular surgery, it remains off-label despite widespread popularity in other countries.2
- Corneal transplant surgery: ICG is used for evaluating endothelial cell usability in donor corneas, as ICG almost exclusively stains dead cells. ICG can also color the corneal stroma of the donor disk, making it effective for deep lamellar endothelial keratoplasty (DLEK).2
- ERM/ILM peel: ICG adheres well to the extracellular matrix components of the ILM and helps facilitate ILM peeling in vitreoretinal surgery. Also, ICG has been proposed to allow better visualization of ERMs in vitrectomy for proliferative diabetic vitreoretinopathy (PDVR), idiopathic ERMs, and proliferative vitreoretinopathy (PVR).2
- Glaucoma surgery: ICG can be used to visualize bleb leakage during trabeculectomy.2
- Strabismus surgery: ICG are good vehicles for staining the superior oblique tendon in strabismus surgery. It stains the tendon’s fascia very well, with no staining of the scleral tissue.2
- Other: ICG aids in the visualization of conjunctival cyst capsules. ICG is injected directly into the conjunctival cyst in combination with trypan blue.2
Assessment using ICG dye
Pros/cons of ICG dye
- Pros: Rates of adverse reactions to ICG (IV) are significantly lower than NaFl. Nausea and vomiting, which are common with NaFl, are rare with ICG.
- Common reactions specific to ICG include urticaria/hives, hypotension, and vasovagal reaction/syncope. Severe reactions such as hypotensive and anaphylactic shock with ICG are rare.15
- Cons: Intraocular use of ICG is off-label. Similar to NaFl, ICG also carries a level of inherent risk as categorized by the latest pregnancy and lactation labeling.
- In addition, ICG is contraindicated in patients with iodine or shellfish allergies, liver disease, and end-stage renal disease.
- Also, there can be toxic retinal damage from ICG-assisted chromovitrectomy like RPE changes, visual field defects, and optic nerve atrophy.16
Note: Infracyanine Green (IfCG) is a green dye with the same chemical formula and similar pharmacologic properties as ICG, except IfCG contains no sodium iodine. The absence of iodine reduces retinal toxicity and permits it to attach firmly to the ILM while not coloring the ERM.16
Trypan blue dye
Uses of trypan blue dye
- Cataract surgery: During cataract surgery, intraoperative TB stains the anterior capsule and its edge intensely, making the differentiation between other tissues easily viewable.2
- Corneal transplant surgery: TB is used to color regions of Descemet’s membrane (DM) lacking endothelial cells as well as the nuclei of injured and dead cells in donor corneas to assess endothelial cell viability.16
- In addition, TB helps in stripping the corneal endothelium from the donor button in deep anterior lamellar keratoplasty (DALK) and Descemet’s stripping endothelial keratoplasty (DSEK).17
- Enucleation: TB is used to stain Tenon’s capsule during enucleation surgery.2
- ERM peel: Because TB has such a high affinity for ERM, it is the dye of choice for ERM identification during chromovitrectomy.2
- Glaucoma surgery: TB can be used to stain the anterior capsule to visualize bleb drainage function during cataract surgery. Mitomycin C and 5-fluorourcil are easily stained with TB, allowing precise placement during filtering surgery.2
- Strabismus surgery: TB, as well as ICG, stains tendon fascia without staining scleral tissue, making it useful in strabismus surgery since it stains the superior oblique tendon so strongly.2
- Other uses:2
- TB is used to coat the phaco incision blade for clear corneal incisions to improve visualization.
- When injected, TB, combined with ICG, aids in the removal of conjunctival cyst capsules.
Pros/cons of indocyanine green dye
- TB is more economical than ICG.
- TB is not toxic to the corneal endothelium.
- TB is considered safe to use in pediatric cataract surgeries.13
- Cons: TB staining might produce retinal damage, especially at higher concentrations.
- The use of TB is contraindicated in the use of dry-state hydrophilic expandable acrylic intraocular lenses (IOLs), as TB can be absorbed by these particular types of IOLs, causing staining and retinal toxicity.2
Brilliant blue G (BBG) dye
Uses of BBG dye
- Cataract surgery: BBG is used to stain the anterior capsule in cataract surgery.2
- ILM/ERM peel: BBG dyes the ILM but not the overlying ERM, causing the ERM to be visible against the blue background of the underlying ILM, called negative staining.
- This helps facilitate the peeling of the ERM. After the ERM is peeled away, BBG is instilled again to stain the ILM, which is then peeled. This process is called double staining.17
Pros of BBG dye
Bromophenol blue (BroB) dye
Uses for BroB dye
- Cataract surgery: BroB is capable of staining the anterior capsule for enhanced visibility during cataract surgery.2
- ERM/ILM peel: Being less toxic, BroB is a safer alternative to ICG for staining the ERM, ILM, and vitreous in chromovitrectomy.2
Cons of BroB dye
Patent blue (PB) dye
Uses for PB dye
- Cataract surgery: PB has been certified in Europe since 2003 for anterior capsule staining during cataract surgery.
- ERM peel: PB is an adjunctive tool in chromovitrectomy to stain the ERM selectively.
Pros/cons of PB dye
- Pros: PB and TB have comparable safety profiles, being that they are both less hazardous to the retina than ICG.
- Cons: PB is not FDA-approved in the US, nor is it certified for vitreoretinal surgery in Europe.13
Triamcinolone acetonide dye
Uses for TA dye
- Anterior vitrectomy: TA can be injected into the anterior chamber to view the vitreous for prolapse.2
- ILM peel: ILM removal with TA yields effective outcomes comparable to ICG-guided ILM removal without the toxic side effects.2
Pros/cons of TA dye
- Pros: TA is a low-cost option as a staining dye. Furthermore, it is hypothesized that using TA as a visual aid may have the extra benefit of reducing post-operative inflammation and vitreoretinopathy.
- Cons: Intra-operative TA during vitreoretinal surgery decreases the risk of post-operative RD, but there is a risk of increased IOP requiring glaucoma drops post-operatively.2