eOphtha

Menu

 

 

Intravitreal Injections -technique and tips

Varsha V. Prabhu, MS; Parag K. Shah, DNB. Department of Retina & Vitreous, Aravind Eye Hospital, Avinashi Road, Coimbatore – 641014, Tamilnadu. E-mail: drshahpk2002@yahoo.co


Definition
Intravitreal injections involves injecting therapeutic agents (drugs/air/gases) inside the vitreous cavity through pars plana under aseptic precautions

Surgical anatomy

Pars plicata
Circumferential zone
2.5mm in anteroposterior diameter

Pars plana
Varies in anteroposterior diameter nasally 3mm wide and temporally 4.5mm wide.This variation is because posterior globe on temporal side curves posteriorly & laterally more than on nasal side .Pars plana extends from pars plicata anteriorly to ora serrata (termination of retina) posteriorly. Blood vessels in pars plana are radially oriented but circumferential incisions across these vessels cause no bleeding .Also, lens zonules insert into ciliary body avoiding pars plana

e10.2

Thus, needle punctures 3.5 mm posterior to limbus enter globe through pars plana

Ciliary body, lens & retina attain adult size by 7years of age
Linear relation exists between the axial length of eye & pars plana during development
Hence in paediatric eyes site of injection varies taking into consideration small size of eye, anterior placement of pars plana & relatively greater size of crystalline lens.

Age

Distance of injection from limbus

1- 6 months

  1.5 mm

6 mths—1year

  2 mm

1—2yr

  2.5 mm

2—6yr

  3 mm

7 yr onwards

  4 mm phakic,
  3.5 mm pseudophakic
  3 mm aphakic

  Table 1: Distance of site of injection from limbus according to age

 


Therapeutic  agent

Indication

Standard dosage

Absolute

Relative

Triamcinolone Acetonide

Refractory CSME, refractory pseudophakic CME, CRVO, BRVO.

-

2 mg in 0.05 ml / 4mg in 0.1ml

Macugen
(pegaptanib sodium)

 CNVM 
  -Wet AMD
  - Non AMD    

Refractory CSME, PDR, NVG, CRVO, BRVO.

0.3 mg in 90 µl

Lucentis
(ranibizumab)

 CNVM 
  -Wet AMD
  - Non AMD    

Refractory CSME, PDR, NVG, CRVO, BRVO.

0.3 mg in 0.05 ml

Avastin
(bevacizumab)

 CNVM 
  -Wet AMD
  - Non AMD    

Refractory CSME, PDR, NVG, CRVO, BRVO.

1.25 mg in 0.05 ml

Vancomycin

Endophthalmitis

-

1 mg 0.1ml

Amikacin

Endophthalmitis

-

0.4 mg 0.1ml

Ceftazidime/cefazoline/cefotaxime

Endophthalmitis

-

2.25 mg in 0.1ml

Amphotericin B

Endophthalmitis

-

5 mcg in 0.1ml

Air

Pneumatic retinopexy

-

0.5-0.8cc

SF6 (100%)

Pneumatic retinopexy

-

0.5 ml

C3F8 (100%)

Pneumatic retinopexy

-

0.3 ml

Table 2: Drugs, indications and dosage

CSME: clinical significant macular edema, CRVO: central retinal vein occlusion, BRVO: branch retinal vein occlusion, CNVM: choroidal neovacular membrane, AMD: age related macular degeneration, PDR: proliferative diabetic retinopathy, NVG: neovascular glaucoma.

Technique

Informed consent clearly explaining what the treatment involves/what to expect/what the risks are 1-3

Equipment

Eyelid speculum, gloves, toothed microforceps, cotton buds, eye drape, callipers, povidone iodine, 0.5% proparacaine, 26 or 30 gauge needle, tuberculin syringe

Preparation & Administration:4-7

Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

Video 1: Anterior chamber tap + vitreous tap (with 24 guage needle) + intravitreal antibiotics injection (with 26 guage needle).

Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

   

Video 2: Intravitreal injection of 0.1 ml triamcinolone acetonide.

Post procedure

Advise patient to administer antibiotic drops qds for a minimum of 5 days postinjection.
They should be instructed to report immediately if any symptoms like eye pain or discomfort, increased redness or additional blurring of vision arise. Floaters are common and should be explained to patients (especially with triamcinolone acetonide)

Follow-up

24 hours after injection. In cases of triamcinolone injections patient is asked to follow-up after 2 wks for intra ocular pressure (IOP) measurement.
In cases of anti-VEGF injections follow-up after 4 wks


Complications

  1. Defined risks (should be included in every informed consent)
  2. Infection (0.16%, 2-year incidence in over 10,000 injections)
  3. Retinal detachment (0.15%, 2-year incidence in over 10,000 injections);
  4. Lens trauma/acute cataract (0.07%, 2-year incidence in over 10,000 injections).
  5. Sub-conjunctival / vitreous hemorrhage
  6. Vitreous wick syndrome
  7. Precipitated angle closure
  8. Elevated IOP with perfusion compromise (CRAO: Paracentesis to be done immediately)
  9. Wound leak and hypotony
  10. Anaphylactic reaction to either the agent or peri-procedural materials.

References:

  1. Jager RD, Aiello LP, Patel SC Cunningham ET. Risks of intravitreous injection: a comprehensive review. Retina 2004; 24:676-698.
  2. Speaker MG, Milch FA, Shah MK et al. Role of external bacterial flora in the pathogenesis of acute post-operative endophthalmitis. Ophthalmology 1991; 98:639-649.
  3. Gragoudas ES, Adamis AP, Cunningham AP et al. Pegaptanib for neovascular age-related macular degeneration. N Eng J Med 2004; 351:2805-2816.
  4. Aiello LP, Brucker AJ, Chang S, Cunningham ET et al. Evolving guidelines for intravitreous injections. Retina 2004; 24: S3-S19.
  5. Speaker MG, Menikoff JA. Prophylaxis of endophthalmitis with topical povidone-iodine. Ophthalmology 1991;98:1769-1775.
  6. Cuilla TA, Starr MB, Masket S. Bacterial endophthalmitis prophylaxis for cataract surgery: an evidence-based update. Ophthalmology 2002;109:13-24.
  7. Ta CN. Minimizing the risk of endophthalmitis following intravitreous injections. Retina 2004; 24:699-705