Seeing Eye to Eye By Lisa Glickstein, Ph.D, Triplet Mom Originally printed in April, 2005 In the dark ages of neonatal intensive care, most premature babies lost their eyesight. Now, this outcome usually occurs only for the earliest premature infants, usually those born prior to 26-weeks gestation. However, most infants born prematurely have an increased risk of a range of eye problems that can affect vision. Retinopathy of Prematurity (ROP) The retina can be imagined to be like a movie screen inside the eye. After premature birth, blood vessels continue to grow across the retina, especially from 32-42 weeks gestational age. Rapid growth is called ROP. ROP is scored according to how dense the vessels are, and where the cluster of vessels is located on the retina. The danger of ROP is that these vessels distort the shape of the retina. Vision will then be distorted, much like trying to watch a movie on a movie screen that isn’t flat. Thus, a small cluster of vessels in the central retina may be worse than a moderate cluster on the edge where it will affect peripheral vision. In the most severe cases, the vessels lead to scar formation, which pulls or puckers the retina and detaches it from the inside of the eye. This is like the collapse of the movie screen. If the retina detaches totally, it results in blindness. Treatment Babies’ eyes are carefully observed in the NICU each week (more often if there is any problem). If ROP at Stage 3 or above is observed, treatment will be started to stop the blood vessels’ growth. This is usually accomplished by laser treatment. If partial or even complete retinal detachment has occurred, the retina can be re-attached using a “scleral buckle.” This can restore partial or nearly all sight. Children with severe ROP are at greater risk for glaucoma and cataract formation, which may require separate treatment. Wandering and Lazy Eyes Wandering eyes (strabismus) and lazy eyes (amblyopia) are not the same condition, although they are related to each other. Strabismus can cause one or both eyes to cross inward, outward, or even up or down. When this happens, the eyes are not working together. Rather than sending two signals to the brain that can be put together into one picture, the eyes are sending conflicting messages. The brain deals with this by ignoring one eye. If both eyes wander, the brain will pay attention to the one that is focused on the object of interest, and by random chance will still get signals from each eye some of the time. If only one eye wanders, the brain will keep ignoring that eye, and over time, the part of the brain responsible for that eye will wither up (atrophy) and vision will get worse. This condition, of an eye that the brain doesn’t use, is called amblyopia. If left untreated, eventually, vision in that eye cannot be recovered. Treatment Strabismus is frequently caused in toddlers by extreme far-sightedness. Toddlers are naturally far-sighted (can see objects far away clearly, but near objects are hard to focus on). If you hold an object close to your nose and try to focus on it, you’ll note that your eyes turn inward to try to focus (accommodate). So toddlers that are far-sighted will cross their eyes when they try to focus on an object somewhat further away (usually within arms’ length). The treatment in these cases is glasses to correct the far-sightedness. If these correct the crossing, and are worn for most of the day, the brain will get signals from both eyes and stay active. Then, as the natural far-sightedness lessens over time, the prescription will be lowered (and maybe not needed anymore) and the crossing will stop. If this doesn’t work, or if the crossing is due to another cause (eyes that cross in a different direction, nerve pathology in Duane’s syndrome, for examples), surgery to change the alignment of the eyes manually may be required. The surgery for strabismus is usually performed as an outpatient procedure, with the child going home the same day. Glasses may still be needed after surgery. Patching the stronger eye, to force the brain to pay attention to signals from the weaker eye, treats amblyopia. This will strengthen the part of the brain responsible for that eye. Patching is now done for no more than two hours per day, during any activity, so can be done at home rather than school, if preferable. Adhesive patches are recommended to completely block vision in the stronger eye (these are like large band-aids), but felt patches that fit over glasses are also available. Frequent appointments are needed to assess vision (usually with simple eye charts) and monitor the degree of crossing, change the prescription of eyeglasses if needed, and assess success of patching. Near-sightedness (myopia) This is a common condition in children and adults, resulting in fuzzy vision for far away objects. The usual onset is during elementary, middle or high school, resulting in complaints of “not seeing the board.” Myopia is often diagnosed initially from in-school screenings at the nurse’s office or at the pediatrician’s. Older children or teenagers may hide their complaint because of fears of getting glasses. Tip-offs in these cases may include declining grades or frequent headaches caused by eyestrain. Another related condition is astigmatism, which can accompany near or far-sightedness. In this condition, the cornea (outer surface of the eye) or lens is misshapen, and distorts the image being projected onto the cornea. It is like projecting a movie through a distorted projector lens. It can cause blurry spots or areas in the field of vision. It is extremely common, occurring in up to a third of children and adults who need vision correction. Treatment Treatment for myopia or astigmatism is glasses, contact lenses, or LASIK surgery. Contact lenses require the child be able to safely insert, remove and care for the lenses, generally by late middle or early high school. LASIK surgery cannot be performed until the prescription stabilizes, usually soon after puberty.