12.2  Posterior Segment Procedures

12.2.1 Fluorescein Angiography

Y (Why Have the Procedure)

“Fluorescein angiography is an important test to study the retina (or “film”) at the back of your eye. It is used to diagnose certain eye conditions and to guide treatment. It is commonly performed in diabetic retinopathy, age-related macular degeneration and diseases affecting the blood vessels in your eye.”

M (Mechanism, What is the Procedure)

“Fluorescein angiography uses a dye to take special photos of the back of your eye (retina)”.

  • “The procedure is performed in the clinic. A yellow dye is injected into a vein in your arm, the dye then travels via blood vessels to your eye. Its passage through the blood vessels in the retina is recorded with a camera. The flash is bright and because the photographs are quite frequent, you may find that you will temporarily lose vision in your eye. The photographer will instruct you where to look.”

C (Complications)

“This is a commonly performed and generally safe procedure, but as with any medical procedure, complications can occur”:

More Common

  1. All patients notice that their skin, eyes and urine turn yellow. This is from the dye and will resolve completely over 1 - 2 days
  2. Nausea (Approximately 1 in 10)
  3. Vomiting (1 in 100)

Less Common

  1. Urticaria (1 in 1000)
  2. Anaphylaxis (1 in 10000)
  3. Death (1 in 200000)

A (Alternatives)

Optical coherence tomography-Angiography (OCT-A), OCT, indocyanine green angiography (ICG) and fundus autofluorescence may offer complementary information.

Extra Questions

  1. Allergies
  2. Pregnancy (probably safe but best avoided if possible)

NB: Renal failure is not a contraindication to fluorescein angiography.

Confirm that the patient understands. Any questions?

12.2.2 Intravitreal Injection

Y (Why Have the Procedure)

“An intravitreal injection is an injection into the jelly inside the eye called the vitreous. This delivers medication to the retina at the back of the eye. It is a commonly performed procedure used to treat a number of conditions including age-related macular degeneration, diabetic retinopathy, inflammation in the eye and diseases affecting the blood vessels in the retina.”

Neovascular AMD

“There are two forms of macular degeneration: wet and dry. You have the wet form where abnormal blood vessels grow underneath the retina causing bleeding that blurs your vision. We now have drugs that when injected in the vitreous can stop the growth of these vessels and reduce the bleeding. Most patients will notice an improvement in their vision. You are likely to require a number of treatments, initially monthly.”

M (Mechanism, What is the Procedure)

“Medication will be given into your eye as an injection”

  • “This will be performed in a procedure room in the clinic. It takes about 5 minutes. Anaesthetic drops will be put into your eye (and sometimes a local anaesthetic injection) so it doesn’t hurt. Your eye and eyelids will be cleaned with an antiseptic to reduce the risk of infection. Your eyelids will be held open with a special clip. Most patients don’t feel the injection. You may see bubbles or fluid swirling as the medicine is injected. After the injection you’ll be able to go home.
  • “I’ll also give you an information sheet and contact number if you have any concerns”

C (Complications)

Most patients tolerate the injection very well.

Common

  1. Grittiness due to povidone-iodine (resolves on its own)
  2. Subconjunctival haemorrhage (“bloodshot eye”)
  3. Floaters

Less Common

Serious complications occur rarely (<0.1%):

  1. Endophthalmitis 1:3000
  2. Cataract due to lens touch
  3. Retinal tear / detachment
  4. Central retinal vascular occlusion - check vision and retinal vascular perfusion post-injection

Any of these complications can lead to severe permanent loss of vision.

Vision

Astigmatism is common
May need glasses/contact lenses/another operation
Takes time for good vision

Specific Considerations:

A) Anti-VEGF Injections

  1. Risk of thromboembolic events: “There are some concerns that it may increase your risk of stroke. The evidence for this is inconclusive, however if you have a history of stroke or heart attack I would like to discuss this with your physician before going ahead with the treatment.”
  2. Contraindication in pregnancy

B) Intravitreal Steroid Injections

  1. Triamcinolone Acetate: 2/3 develop glaucoma; 1/3 require glaucoma surgery
  2. Dexamethasone intravitreal implant (Ozurdex): 1/3 develop glaucoma; 1% require glaucoma surgery With both options cataract will eventually develop

A (Alternatives)

  1. No treatment: Likely to lead to further vision loss / blindness
  2. Photodynamic therapy
  3. Thermal laser

Confirm that the patient understands. Any questions?

12.2.3 Macular Laser

Y (Why Have the Procedure)

“You have swelling at the back of your eye (“retina”) due to leaking blood vessels from diabetes / vein occlusion. This swelling is causing a reduction in your vision (“wet camera film” analogy)”.

Aims:

  1. Reduce the leak
  2. Maintain your vision (ETDRS: 50% reduction in moderate vision loss, don’t promise that vision will improve)

M (Mechanism, What is the Procedure)

  • “Laser is used to seal off leaking blood vessels at the back of your eye.”
  • “It is performed on a laser “slit-lamp”. You will be given anaesthetic drops and a contact lens is placed on your eye during the procedure. You should not feel pain. You may need more than 1 treatment session (usually 3 months later). Immediately after the laser you won’t see much but your vision will gradually come back over the next few hours.”

C (Complications)

Although macular laser has a good success rate, complications may occur:

  • Central / paracentral scotoma: Inadvertent foveal burn (“may lose central vision but won’t go blind”), scar expansion, foveal lipid dump


Stress close follow-up, need for urgent review if vision declines.

A (Alternatives)

  1. Observation: Higher risk of vision loss
  2. Intravitreal anti-VEGF: First-line treatment in most patients
  3. Intravitreal triamcinolone: Risks of intravitreal injection / cataract / glaucoma

Confirm that the patient understands. Any questions?

12.2.4 Pan-Retinal Photocoagulation (PRP)

Y (Why Have the Procedure)

“You have advanced damage to the back of your eye (“retina”) from diabetes. This has resulted in the growth of abnormal blood vessels in the retina. If left untreated these blood vessels can bleed (reducing your vision) or cause scarring and retinal detachment.”

Aims:

  1. Regress the vessels
  2. Prevent bleeding in the eye (vitreous haemorrhage) or retinal detachment, which can result in severe vision loss

This is the mainstay of treatment for proliferative “severe” diabetic retinopathy and has been demonstrated to reduce the risk of severe vision loss by 50% (Diabetic Retinopathy Study DRS).

M (Mechanism, What is the Procedure)

“Laser targeting the peripheral part of the back of your eye (“retina”) is required to prevent bleeding and preserve your central vision.”

  • It is performed on a laser “slit-lamp”. You will be given anaesthetic drops and a contact lens will be held on your eye. You may feel some discomfort- let me know if it is getting too sore. You will likely need several treatments over a few weeks. Each session takes around 10 minutes. Immediately after the laser you won’t see much but this will gradually come back over the next few hours.”

C (Complications)

“Although PRP has a good success rate, complications may occur:”

Pain / Discomfort

Can have peribulbar anaesthetic if unable to tolerate

↓ Peripheral / Night vision

↓ Night Vision (Nyctalopia)

Loss of Near Vision

Reduced accommodation in pre-presbyopic patients

Vision Loss

Uncommon (worsening of macular oedema, inadvertent foveal burn, CNV)

Stress close follow-up, need for urgent review if develops reduced vision.

A (Alternatives)

  1. Observation: Higher risk of vision loss
  2. Intravitreal anti-VEGF: Temporary effect only. Risks of intravitreal administration.
  3. Cryotherapy of peripheral retina

Confirm that the patient understands. Any questions?

12.2.5 Photodynamic Therapy (PDT)

Y (Why Have the Procedure)

“You have an abnormal blood vessel or vessels in the back of your eye that could result in long term vision loss without treatment. This treatment helps to seal off those abnormal blood vessels.”

PDT can be used for central serous chorioretinopathy (CSC) as well as certain types of wet age-related macular degeneration (polypoidal choroidal vasculopathy).

Aim: Stop further leaking and stabilise vision, may improve vision in some cases.

          

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