The Risks of Eye Injections

The Risks of Eye Injections

The risks and complications of  injections into the eye are low.  The most dreaded complication of intravitreal injections is infection inside the eye (aka endophthalmitis).  The risk of endophthalmitis is reported to be about 0.09%.  Endophthalmitis can cause blindness.

As more and more intravitreal injections are delivered for the treatment of diabetic retinopathy and wet macular degeneration, the concern for causing blinding infection becomes greater.  The rates of infection have always been low, in fact, so low, it is difficult to estimate and study.

Intraocular Injection, Randall V. Wong, M.D., Retina Specialist, Fairfax, Virginia

Intraocular Injection

Complications of intraocular injections include;

  • Subconjunctival hemorrhage – bleeding outside the eye (scary looking), but benign
  • Pain/Discomfort
  • Cataract
  • Vitreous Hemorrhage – bleeding inside the eye
  • Retinal Detachment
  • Endophthalmitis – infection inside the eye

Retinal Detachment and Infection are the biggest concern.  The other “complications” are rather soft and either don’t cause damage or are reversible (cataract and vitreous hemorrhage).

Retinal detachment can occur if the needle enters the eye in the wrong spot and causes a hole/tear in the retina.  Additional surgery may be needed depending upon when this complication is diagnosed.  Retinal detachments can potentially cause permanent loss of vision depending upon timing.

Endophthalmitis is a nightmare.  It may occur in any intraocular procedure where the eye is penetrated by a surgical instrument.  It happens so infrequently, that it is difficult to really measure the rate at which it occurs and to study just how it occurs.  In theory, bacteria on the outside of the eye gets inside.  Does this happen during surgery, or, after?  We don’t really know.

You Have a Dirty Mouth – The eye, nose and mouth are all connected.  This is why you blow your nose after crying.   Your eye is as dirty as your mouth and nose.  There is a lot of bacteria that can cause an infection.

Pre-Operative Antibiotics are controversial.  In theory, it makes sense to treat the eye with antibiotics prior to anticipated surgery or injection.  Many cataract surgeons prescribe antibiotic drops prior to surgery, but many don’t.  The rate of infection is so low, it is hard to measure.  Many retina specialists prescribe antibiotic drops prior to intraocular injection, but many don’t (I do).

A study was just published that found no difference in the rate of infection between using antibiotics before (and after) injection compared to no antibiotics.  Over 3800 injections were studied.  What is crucial; however, is the use of a lid speculum (small wire device that keeps the eyelids spread apart) and the application of a topical iodine/povidone antiseptic.

What Does This Mean? My point is to highlight that the risk of blindness due to infection is low in intraocular injections.  As injections become more widely used for diabetic retinopathy and macular degeneration, we’ll be able to better define the rate and causes of this potentially blinding complication.  Incidentally, as the use of sustained release technology is emerging, infection will become less of a concern as fewer ‘injections” will be necessary.


Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist
Fairfax, Virginia

  • Pingback:Ozurdex Implant Treats Retinal Vein Occlusions
    Posted at 07:57h, 11 April Reply

    […] told my patient about Ozurdex.  I told him that the major risk of injections is the possibility of blinding infection (endophthalmitis) which is estimated to be about 1/2000 […]

  • Jeffrey M Keil
    Posted at 11:18h, 16 June Reply

    My daughter has a severe form of FEVR (Familial Exudative Vitreoretinopathy). Unfortunately, she has developed secondary neovascular glaucoma. At this point, the only intervention that has prevented full progression to closure of her angles is Avastin injections every 6 weeks. This may seem trivial, but her retinologists not only recommend antibiotic eye drops after the injections but also no swimming for 5 days afterward. My daughter is an avid swimmer and this significantly limits her activities. Is there any evidence to recommend such a limitation? My wife and I are both primary care physicians. My tendency is to give her 2d off and then let her swim (injection site should be healed in that time). My wife is a believer in following orders to the letter.

    What are your thoughts?

    thanks so much for your time. Jeff Keil

    • Randall V. Wong, M.D.
      Posted at 10:17h, 20 June Reply

      Dear Doc,

      With regard to swimming. My recommendation is to let her swim. I presume that her docs are concerned about intraocular infection (endophthalmitis) as it could blind her.

      In my opinion, swimming in a chlorinated pool would be safe as;

      1. The conjunctival “wound” would probably heal rapidly (<24 from a needle wound).
      2. The water is chlorinated
      3. The eyes, mouth and nose are all interconnected anyway….loads of bacteria anyway!
      4. I don't know of any evidence to support their worries.

      Here's an article I wrote last year about the eyes, nose and mouth being connected.

      Good luck Dad!


  • Marietta Ogarek
    Posted at 09:50h, 10 July Reply

    Dr. Wong,
    I’ve been receiving Avastin and now, Eylea injections ….Avastin for 5 years, and now
    Eylea for the last year. Both have worked fine for me. Sometimes I get a black circle that I see for sometime…a day and goes away overnight. I received another injection of Eylea yesterday, and I’m still seeing that black circle.
    It looks like a bubble. How long do these last? I don’t ever feel any pain with these injections.
    Love your column.

    • Randall V. Wong, M.D.
      Posted at 14:51h, 12 July Reply


      Probably (and no way for me to say for sure!) just tiny bubbles of air. In my experience, these absorb within about a day.

      Thanks for reading!


Post A Comment