In this lecture, the basics of pediatric eye examination for primary care nurses are covered by Dr. Neely. The lecture contains the overview of the prevalence of blindness, anatomy of the eye, diseases of the eye, basic eye examination and supplemental videos.
Narrator: Dr. Daniel Neely. Created by Orbis International and the KwaZulu-Natal, South Africa Health Department with the generous support of Kenneth Youngstein.
Greetings. And welcome to the Pediatric Eye Examination: A Guide for Primary Care Nurses. In this presentation, we will touch on the general causes of blindness, anatomy of the eye, diseases of the eye, and we’ll provide supplemental videos for later viewing. On the topic of blindness we will discuss world blindness, but we will largely concentrate on childhood blindness and its causes. Keep in mind that as a nurse, you can help prevent childhood blindness.
World blindness is a significant problem with at least two billion people in the world who are blind or visually impaired. The most common cause being uncorrected refractive error, or needs for glasses. Followed by diseases such as cataract, glaucoma, corneal scarring, for infractions such as trachoma. And a majority of these patients live in rural areas where it is very difficult to receive care.
The good news is, 80% of blindness can be prevented through early detection and treatment. Childhood blindness, specifically, is also a significant problem. While frequently not thought of as affecting children, blindness occurs in 1.4 million children in the world. Many more have significantly reduced vision. Not only does this affect their vision, but it also affects their lifespan. 50% of children who go blind will die within two years. Again the good news is a significant percentage of this, approximately 50% of childhood blindness, can be prevented through early detection and treatment. This is where nurse screenings are particularly important.
The causes of childhood blindness are many. Congenital cataracts, congenital glaucoma, cancers such as retinoblastoma, premature birth or retinopathy of prematurity, infections such as trachoma, injury from chemical burns and trauma, and even the traditional eye medications can be causing harm rather than helping.
Reduced vision in children is frequently from strabismus, also known as squint, and amblyopia or lazy eye. If not treated, these conditions result in a decrease in vision in one or both eyes. A very common cause of refractive errors and decreased vision, is a need for glasses. If children do not receive glasses to correct their refractive error, this can lead to problems in school and their social life, as well as leading to the conditions of squint and lazy eye. Other conditions that you will encounter include nystagmus, or shaking movement from the eyes, one cause of which is albinism. This is noticed to be less pigment of the skin and eyes or just the eyes.
Nurses can prevent childhood blindness by screening newborns, infants, and children. You, the nurse, can identify causes of blindness while still treatable. And this only takes a few minutes of time and no special equipment is needed. The process is to screen, identify the problem, and refer the child for further care.
Section Two: Anatomy of the Eye. In this section, we will touch on the external anatomy of the eye, including the eyelids, conjunctiva, sclera, and cornea, the eye muscles, of which there are six on each eye. And the internal anatomy of the eye, which most of us are less familiar with. These internal structures include the iris, the pupil, the lens, the vitreous gel, the retina, which makes the picture, and the optic nerve which carries the picture to the brain.
When we talk about the external anatomy of the eye, people frequently refer to the pupil and iris. It should be kept in mind that the pupil is the black hole in the middle of the iris. The white part of the eye is the sclera, although it is covered by a thin layer called the conjunctiva.
Each eye has six muscles which move it side to side, up and down, and also provide rotation of the eye. Internally, we have, once you pass through the cornea and the pupil, then we have a lens of the eye. The lens of the eye is where cataracts occur. Behind the lens we have the vitreous humor, which is a thick, gel-like substance that is transparent. And along the back wall of the eye, we have the retina, which makes the picture and the choroid which provides blood supply to the retina. From the retina, the picture travels through the optic nerve to the brain. This entire system is what gives us vision.
Section three: diseases of the eye. As we discuss diseases of the eye, we will touch on the external diseases: things such as the eyelids, red eyes, or conjunctivitis, and the cornea. We will also discuss the importance of a white pupil and how this can be screened. This white pupil is critical because it can be a sign of a congenital cataract or retinoblastoma tumors.
Another blinding condition of children, which we will discuss, is congenital glaucoma or high pressures in the eyes. Also there is retinopathy of prematurity. This is a blinding retinal disorder which is on the rise in developing countries. We have previously touched on squint, also known as strabismus, which is where the eyes are not aligned together. And again, refractive errors which are the most common cause of visual impairment.
Diseases of the external eye are usually notable as lumps, bumps, sores, swelling, redness of the skin, drooping eyelids, discharge or crusting from the eyelashes. And all of these are reasons for referral. Many bumps, such as the one seen here, can be related to plugged glands around the eyelids. And one common easy treatment is to start warm compresses to improve drainage of the glands.
Ptosis is the medical term for a drooping eyelid. All cases of ptosis, or drooping eyelids, need to be evaluated. Particularly if they are present at birth or develop suddenly. Red eyes are common. It is very difficult to tell the cause of a red eye just by looking at it. However, some common causes are infections, bleeding, or inflammation. While these may be easily treated by an eye professional, it can be very difficult for the primary care provider to determine what is causing a red eye. And if not treated, some red eyes may lead to corneal scarring or blindness. Therefore, it is usually recommended to refer all red eyes to an eye clinic.
Corneal ulcers and opacities. The cornea is the window to the eye. It is normally quite clear, with no visible haze, cloudiness, scars, or blood vessels. Through the clear cornea, one can usually see the round pupil of the iris. If any of these things are noted to be abnormal, you should refer all corneal abnormalities to an eye clinic immediately.
The white pupil. This is an urgent finding and it’s something that all children should be checked for. The white pupil, as seen in the photograph on the right side, in the patient’s left eye, can be a symptom of cataract, clouding of the lens, or retinoblastoma tumors inside the eye. Sometimes they can be noticed by the parent or caregiver, but other times they may only be noticeable on examination. This examination is the red reflex test. All white pupils should be referred for further investigation immediately.
Cataract. The normal lens of the eye is crystal clear and allows light to reach the retina, forming a picture that is then transmitted to the brain. A cataract is when that lens becomes cloudy. Clouding of the lens locks light, or the image, from reaching the retina. In children, especially young children, the retina and brain need a clear image to develop normal vision. Untreated cataracts can lead to permanent loss of vision and therefore should be referred immediately and promptly. This highlights again the importance of the red reflex text.
While it may seem strange, children do in fact develop cancers of the eye. Retinoblastoma is the most common eye cancer of children. It is important to identify, because when detected early it has a high rate of cure. However, when detected late, it may be too advanced and require removal of the eye or lead to death of the child. Therefore, again, the red reflex test is very important and any white pupil must be referred urgently. The child on the right is an example of an advanced retinoblastoma, where the tumor has eroded through the eye and now is likely to cause the death of this child.
Glaucoma is high pressure inside the eye. In congenital glaucoma, this is usually from a birth defect. And fluid is being formed inside the eye, but is not leaving the eye through normal channels. This increased pressure leads to damage of the optic nerve, clouding of the cornea, and an eye that appears to be larger than normal. Sometimes this occurs in other family members and is an inherited condition. Always refer all suspected cases of glaucoma.
Children with congenital glaucoma will show signs of light sensitivity or photophobia, they may have excessive tearing, and the cornea may be cloudy or even enlarged. The normal cornea is approximately 12 millimeters in diameter from side to side. In cases of congenital glaucoma, the cornea may be larger and may look like a cow’s eye. What we call buphthalmos. In these patients, the cornea may be 13 or 14 millimeters in diameter.
Retinopathy of prematurity is an increasing problem all around the world. It largely affects preterm infants, those born less than 32 weeks of gestational age. Keep in mind that a normal pregnancy is 40 weeks gestational age. It is more likely to occur in low birth weight newborns, those less than 1,500 grams, and it is also more likely to occur in those infants who require supplemental oxygen.
Retinopathy of prematurity is when the retina fails to grow normal blood vessels. It leads to an abnormal neovascularization, similar to what diabetics experience. These neovascular vessels also have scar tissue with them and it leads to contraction or detachment of the retina. Because the retina is what makes the picture in the eye, this leads to blindness which is usually not treatable.
However, if screened early on four to six weeks after birth, and on a regular basis thereafter, if the retinopathy is identified in its early stages it is quite treatable and this retinal detachment can be prevented. As babies begin surviving to younger and younger ages and smaller birth weights, the incidence of retinopathy of prematurity is increasing in developing countries around the world. You should refer all preterm and underweight infants to specialty hospitals for screening and treatment.
We have mentioned squint before, the other term for squint is strabismus. This means that the eyes are not properly aligned with each other. They can be crossing in, they could be drifting out, or they can be misaligned up and down. Squint, or strabismus, can be constant, it can be intermittent, it can appear in one eye and then the other, or alternating. And sometimes it is only seen when the child is tired. Esotropia is specifically strabismus where one eye is crossed in towards the nose. Exotropia is when one eye is deviated outward. Hypertropia is an upward deviated eye and hypotropia is a downward deviated eye.
So why treat squint or strabismus? Is it just cosmetic? Well, no, in fact it’s not. When the eyes are not properly aligned, the brain does not want to see double vision. And it will start to suppress or not use one eye. This leads to amblyopia, what some people term: lazy eye. Essentially what happens with amblyopia, is that the brain stops using the eye. If this is not caught in a timely fashion, it leads to permanent blindness or decreased vision. And at a certain point the brain is no longer capable of learning to see with that eye.
Amblyopia, or lazy eye, should be detected and treated before five years of age. Many times by age five to seven or eight, it is already permanent. Sometimes the treatment of squint, or strabismus, can be as easy as providing eyeglasses or spectacles. In addition to producing amblyopia, misalignment of the eyes can lead to problems with depth perception, difficulty with school, play, or work, and poor self-image, or teasing by other children. You should refer all cases of suspected squint or strabismus.
Refractive errors. Refractive errors are blurry vision needing glasses. If they are not corrected with glasses or spectacles, refractive errors can lead to permanent decrease in vision, and decreased development, and quality of life. With normal vision, the cornea and the lens focus light coming into the eye, and bring it to a sharp focus right at a focal point on the retina. This image is then very clearly seen.
However, in myopia, also termed nearsightedness for shortsightedness, the cornea and lens are focusing too strongly and the light is focused in front of the retina. This leads to a blurred image on the retina, and the brain perceives a blurry picture. This makes it difficult to see things further away.
Hyperopia, also termed for farsightedness or longsightedness, is the opposite problem. It is difficult to see things up close. This is similar to what happens to people as they age and develop another condition called presbyopia. In these cases, the cornea and the lens are not strong enough and the image is being focused behind the retina. So again, the brain is seeing a blurry image rather than a sharply focused image.
Astigmatism is another variety of refractive error. You can think of this as irregular focusing where there may be two focal points at different points inside the eye. Therefore, the brain is perceiving a double image or blurred image. And this is true for things far away and up close. Astigmatism can be caused irregularities of either the cornea or the lens shape.
Section four, the eye examination. In this section we will talk about what you need to perform a screening eye examination, how to obtain a useful patient history, how to perform visual acuity testing, inspection of the external eye, white pupil testing, looking for cataract and retinoblastoma, eye alignment testing, looking for strabismus or squint, using the two techniques of the Hirschberg test and the Cover test. We’ll also touch on examining infants and some of their particular needs.
In general, when using an examination room you will need two chairs. One for you and one for the patient or caregiver and child. It is helpful to have a small light source, such as a penlight, or small torch. Also a standard direct ophthalmoscope, either battery-powered or rechargeable. And then small objects of interest that the child will either look at and focus on, or contract as you move them around. Also, always keep in mind when testing visual acuity, that you want to use an eye chart which is age and literacy appropriate.
The first step in performing eye screening is to speak with the parent, or caretaker, and obtain a history. If possible, speak directly with the child. General questions to ask when taking a patient history are: Have you seen anything abnormal with your child’s eyes? Do you think your child has a problem seeing? Have you seen a white pupil or a white spot in your child’s eyes? Do any family members have eye problems? This last one should always be kept in mind as many eye conditions are hereditary and passed on from one generation to another.
Other things to discuss with the child or caregiver: Have you noticed that your child’s eyes tear a lot or are light sensitive? Does your child watch television? If so, do they seem to like to be particularly close to the television? If your child reads or draws, do they hold their head very close to the paper? When your child plays with toys, do they hold a toy very near to their eyes? These things can be a sign of nearsightedness or shortsightedness.
If the patient or the caregiver does reveal a problem in the history, you should explore this. When did the problem start? Has the problem stayed the same, become better, or gotten worse over time? What treatment have you already tried?
As you look at the child’s eyes, the eyes should be bright and clear with white sclera and black, round pupils in the center. There should be no lumps or crusting of the eyelids. The child should be able to fix steady on an object with no shaking eye movements. And they should be able to follow moving object with both eyes together and then with each eye individually.
One quick and easy vision test that you can use on younger children, in particular, involves placing a small sweet or object of interest in the palm of your hand. Do this without showing the child which hand you’re placing it into. Then, open your hands and see if the child can identify which hand has the sweet or object in it. Once you’ve done this with both eyes open, you may repeat it with first the left eye covered, and then the right eye covered. It is best to use a patch or occluder rather than a hand, as the child may peek through the fingers of a hand.
If children are older and able to cooperate with visual acuity testing, generally at four to five years of age and up, it is preferred to perform vision testing with an eye chart. To do this, you will need a well-illuminated room, a distance from the child to the eye chart of either three or six meters, and an appropriate eye chart which is calibrated for either three or six meters. It is also helpful to have a pointer, such as a long stick, a pencil, or a knitting needle. This will allow you to point to letters or numbers without blocking the view of the child.
There are many types of visual acuity test charts, however some are better than others. The best ones are well-constructed letter charts, such as the Snellen, the Slone, the HOTV, seen on the top right here, and Lea symbols which are seen on the bottom right here. These charts are preferable because they are evenly constructed and have uniform spacing and uniform numbers of optotypes on each line.
Frequently, if a child is unable to verbally identify the letter or symbol, it may be easiest for them to simply have a matching card and point. Which test you use will depend on not only the patient’s age, but also their literacy level.
When starting you may begin the test with both eyes open to ensure the child is able to easily perform the test. Begin by pointing to one of the larger letters or numbers, such as the top line, and work your way across and then down the eye chart. Let the child tell you what the letter or number or optotype is, and if they aren’t comfortable saying it, let them use a matching card and point to it while they hold the card on their lap. Do not tell them if they are correct or wrong, and do not give them hints. Move your way across each row and then down to the next line until the child can no longer pass the acuity test. Typically, to be given credit for a visual acuity line, one must identify the majority of the optotypes on that line.
It is preferable to have the eye not being tested covered with a patch or a solid eye occluder. Do not use the child’s hand or that of a parent, as it is frequently easy for the child to peek between the fingers and then the test results will be inaccurate. After testing the right eye with the left eye covered, then test the left eye with the right eye covered. All school-aged children with worse than 20/40 or 6/12 vision should receive further evaluation.
We have mentioned the white pupil red reflex test and how important this is. The white pupil test is used to visualize anything that might block the light passing through the eye. This would include cataracts, tumors such as retinoblastoma, cloudy corneas, et cetera. You will see a standard direct ophthalmoscope as illustrated here. The ophthalmoscope is assembled by taking the two parts, inserting the head into the charging handle, and twisting it. The ophthalmoscope is then turned on by depressing the green button on the sleeve and rotating the black sleeve.
There are dials or diopter settings on the head of the ophthalmoscope. And in general, you should just set this to the reading zero. You want to use the white light, in general, and not the green or blue lights.
When testing for red reflex, you should look through the ophthalmoscope with one eye, with the patient at approximately an arm’s length away. Focus the light on one eye of the patient and then switch to the other eye. It is helpful to have the lighting dim in the room while doing this. This will give the larger pupil size and a better visibility of the red reflex. Normally, the pupil on the red reflex test will appear red or orange in color. If it appears white or hazy or dark, this is abnormal. Some white pupils may be so prominent that they are visible to naked eye and even the parents may see them. Again, immediately refer any child with a white pupil, evaluation should not be delayed.
The Hirschberg test is a simple test for assessing eye alignment or strabismus. It utilizes a small torch or penlight. Sit in front of the child at arm’s length, ask the child to look at your nose, and while centering the small light or torch in front of you, aim the beam centrally between the patient’s two eyes. It should illuminate both eyes. What you are looking for is the reflection off the cornea of both eyes. These corneal light reflections should be centered in the pupil or very close to it.
This is a normal Hirschberg test. You can see the light reflection is essentially centered in the pupil. This is an abnormal Hirschberg test. On the patient’s right eye you can see that the light reflex is almost to the sclera. This indicates that the eye has deviated outward or exotropic. In the lower example, the eye is deviated the other way. The light reflex is near the outer edge of the iris, close to the sclera, indicating that the eye is deviated inward or esotropic. Here is a video of the Hirschberg test.
[Sibongile] The Hirschberg test. This is a test that is done to test if the eyes are straight. So it’s a test we use to detect squint. Penlights can be used as a torch or you can use an ophthalmoscope. But remember, in this instance, the ophthalmoscope is used for lighting. The light is shone at the center of the forehead, between the eyes. The distance of the torch should be half a meter away from the patient. When you look at the patient’s eyes, with the light shone between the eyes, you should be able to see two tiny reflections of light. This reflections should be at the center. In a normal eye the reflections should be at the center of the eyes, on both eyes. If the reflection is away from the center of the cornea, that means that eye is squinting. It can be on both, the reflection can be away from the center of the cornea on one or both eyes.
[Daniel] The Cover test is another test for squint or strabismus. When performing the Cover test, you will have the child fixate on an interesting toy, object, or light in front of you, with both eyes open. While they fixate at the near or distance object, cover one eye and watch the other eye for a refixation or repositioning movements. This may be in, out, up, or down, and occurs in the uncovered eye. Then, remove the cover and watch the uncovered eye for additional refixation movement.
With the Cover test, we again have the child fixate on a target. Cover one eye and watch for movement of the other eye. If the other eye moves inward, that indicates that it was exotropic or outward deviated. If the uncovered eye moves outward, that means that it was deviated inward or esotropic. You then remove the cover from the covered eye and continue to look at the uncovered eye. If it moves to a new position, this confirms misalignment, strabismus, or squint. Refer all strabismus or squint cases for further evaluation.
In this video, we will demonstrate the Cover test.
[Sibongile] (speaking in foreign language) Oh, beautiful!
(speaking in foreign language) Oh, beautiful!
[Daniel] Examining infants can be particularly difficult. Try to keep them happy and as comfortable as possible, and move quickly to collect your information. If an infant is particularly tired or squirming, you can try to sooth them by wrapping them in a blanket to complete the examination. This video demonstrates how to wrap and examine an infant.
[Sibongine] (speaking in foreign language)
(baby fussing) Oh, beautiful!
[Daniel] Referral. When needing to refer a child, children must be seen promptly by an eye care professional: an ophthalmic nurse, an optometrist, or an ophthalmologist. Many of the eye conditions affecting children are very time-sensitive. Particularly urgent referrals, things such as white pupils, cataracts, glaucoma, retinoblastoma tumors, should all be seen within a week, whenever possible. It is also important to convey the importance of the further examination to the parents, educate them, and have them understand why it is urgent to have follow up.
If you would like to obtain additional information and have free vision screening resources, AAPOS, the American Association for Pediatric Ophthalmology and Strabismus is a fantastic source. They can be reached at www.AAPOS.org. Here you will find vision screening information, frequently asked questions, and information for nurses.
On behalf of the staff and donors of Orbis International, I thank you for your attention.