1.     What is the retina?

The eye is a hollow sphere, and the retina the inner lining of the eye wall.  It is the structure responsible for capturing visual information and sending it to the brain.  There are multiple layers to the retina.

The blood vessels which supply oxygen to the retina lie in the innermost layers.

2.     What is retinopathy of prematurity (ROP)?

ROP is a disorder of the blood vessels of the retina (the light sensitive part of the eye) that occurs in some premature babies.  ROP is one of the leading causes of blindness in children.

3.     Which infants are at risk for ROP?

In general, ROP is a disease affecting the youngest, smallest and sickest infants.  Typically, this includes infants born earlier than 32 weeks of gestation and under 1500 grams (about 3.3 pounds).  The smaller and more premature the infant, the greater the risk.

4.     How does an infant get ROP?

It takes a full term (40 week) pregnancy for the blood vessels which will supply oxygen to the retina to fully develop.  The blood supply to the retina starts at the back of the eye at 16 weeks of gestation.  The vessels gradually grow over the surface of the retina to reach the front edge at about the time of birth.

When an infant is born early this process stalls.  There are a variety of reasons this occurs, but the most important ones in babies born today are the degree of prematurity and birth weight.

Once the blood vessels stop growing over the surface of the retina, a patch of retina ends up starved for oxygen.  At this point:  either the blood vessels pick up where they left off and finish the growing normally (see #5 below), or ROP begins to develop (see #7 below).

5.     Do all babies born prematurely get ROP?

No.  In most infants (85% of those at risk) the blood vessels finish growing over the surface of the retina as they were supposed to, although finishing the job a few weeks later than the original due date.

6.     Do all babies who get ROP require treatment?

No.  In most infants the ROP will subside (regress) on its own.

7.     What are the different stages of ROP?

Retinopathy of prematurity (ROP) has been divided into five stages.  Stages 1 and 2 customarily get better on their own.  Some eyes, however, go on to Stage 3 retinopathy of prematurity.  Stage 3 ROP exists when these disturbing new blood vessels grow out from the ridge in the retina toward the center of the eye.  If this blood vessel growth becomes severe and is accompanied by “plus” disease (enlarged and twisting blood vessels in the back part of the eye), the child may reach the point where treatment of the peripheral retina with laser (or rarely freezing) treatment is performed.  When stage 4 or 5 ROP is reached, the retina is detached.

8.     Can ROP get better or heal on its own?

Yes – in fact most infants do.  It is called “regression” of the disease, and occurs when the retinal blood vessels grow to cover and nourish the retina, and whatever stage of ROP was present fades.  See the answer to Question #5, above.

9.     Can ROP lead to blindness?

Yes.  Eyes which progress to stage 4 or 5 can go blind.  This may happen even when a child is properly screened and is properly treated in a timely fashion.

10.  What treatments are there for ROP?

Currently, the standard of care treatment for ROP severe enough to require it is destroying the retina without blood vessels with laser.  On occasion, freeze-treatment is used to accomplish the same goal.  By destroying the peripheral retina the goal is to save central vision so that the infant can have as normal vision as possible.  Other experimental treatments are being studied as well – most notably a drug called Avastin (bevacizumab).

Once the retina detaches (Stage 4 or 5), there are surgical therapies which may be employed to salvage vision.

11.  How are at-risk infants followed?

They are examined either at the bedside or by digital pictures, generally on a weekly basis.

12.  Is my child “out of the woods” in terms of ROP risk once s/he is discharged?

Usually not.  Infants at risk for ROP are followed until 52 weeks after conception.  Since most infants are discharged from neonatal intensive care well before that age, in general some exams are still necessary in the weeks following hospital discharge to ensure the best visual outcome for your child.

13.  How important are follow-up visits for ROP?

Failing to keep follow-up appointments puts your child at risk of blindness.

14.  When are infants with ROP treated?

Most infants requiring treatment for ROP are treated at about 35-36 weeks post-conceptional age (typical range 32-40 weeks).

15.  What is the treatment procedure?

The baby’s eyes are dilated, a lid speculum is used to hold the lids open, and the peripheral retina is treated with the laser.  Treatment can be done either under general anesthesia, or sedation with local anesthesia.

16.  Is treatment for ROP painful?

Without anesthesia it would be a painful procedure.  There is no pain after the treatment is completed.

17.  What is the treatment success rate?

On the order of 85% of eyes requiring laser are effectively treated.

18.  What will my child’s vision be after treatment?

It depends on the stage and severity of ROP.  The less scar tissue present at the time of treatment, the greater the potential for visual development.  Eyes treated at stage 2 or 3 may see as well as 20/40 or better.  Eyes at early stage 4 often see as well as 20/80 - 20/200.  About half of eyes at more severe stages of stage 4 see better than 20/2000 (ambulatory vision).  Ambulatory vision is defined as being able to see objects and move around a room without stumbling or bumping into obstacles.  Surgery for stage 5 ROP is often done to preserve vision in the range of ambulatory vision to light perception.

19.  What is the impact of the laser on a child’s field of vision?

Peripheral vision (“side vision”) is usually reduced by laser treatment.  Some side vision is sacrificed in the interest of preserving central vision – what we all use to read, drive, etc.

20.  What if treatment fails?

When stage 4 or 5 ROP is reached, the retina is detached and other therapies can be performed.  One such therapy is scleral buckling, which involves encircling the eyeball with a silicone band to try and reduce the pulling on the retina.  The most commonly performed surgery is vitrectomy (removal of the gel-like substance called the vitreous that fills the back of the eye).  Sometimes the removal of the lens as well is required if the retina is touching the back surface of the lens, which would make it impossible to enter the eye.

21.  What is the impact of low vision on development?

Infants and children with visual impairment often have a different timeline for hitting traditional developmental milestones.  Assuming there is no other health problem beyond vision – and many premature infants have other health issues - the reason is many of the developmental items your pediatrician will look for rely on vision to some degree:  raising the head for an infant, walking for the toddler-to-be.  Children with low vision still hit such milestones, though they may take a bit longer to do so.

22.  What happens once the ROP regresses?

ROP is a lifelong disease, whether it resolves after treatment or gets better (regresses) on its own.  Formerly premature children and adults require ongoing care for nearsightedness (myopia), amblyopia (“lazy eye”), glaucoma (high eye pressure), retinal detachment, and early cataract.

23.  Does my child have any activity limitations because of ROP?

Usually not.  Most children with regressed ROP live normal lives.  On occasion, children with more advanced stages of ROP may have limitations with regard to contact sports, ball sports, and the like.

For other information see:  http://www.nei.nih.gov/health/rop/