- Pediatric Eye ExaminationYogesh Shukla
- Vision Assessment in Infants and ChildrenRohit Saxena, Vaishali Rakheja
- Management of Refractive Errors in ChildrenYogesh Shukla
- Accommodative Anomalies in ChildrenYogesh Shukla
- AmblyopiaEdward Kuwera, Courtney L Kraus, Oded Lagstein, Adrianna Jensen
- Conjunctival Inflammatory and Allergic Disorders in ChildrenAhmad Kheirkhah, Vadrevu K Raju
- Disorders of Pediatric Cornea and ManagementNamrata Sharma, Rasik Vajpayee, Rinky Agarwal, Mohamad Ibrahime Asif, Priyadarshini KM
- Pediatric UveitisVishali Gupta, Nitin Kumar Menia, Aniruddha Agarwal
- Pediatric CataractAbhay R Vasavada, Vaishali Vasavada
- Congenital GlaucomaSamiksha Fouzdar Jain, Mehmet C Mocan
- Lid and Adnexal Anomalies in ChildrenMichael O'Rourke, Thomas Hardy
- Neuro-ophthalmological Disorders in ChildrenSangeeta Khanna, Joseph Conway, Swati Phuljhele
- Pediatric Ocular Congenital VasculopathiesMarina Roizenblatt, Emmanuel Y Chang, Kim Jiramongkolchai
- Retinopathy of PrematurityRajvardhan Azad, Sony Sinha, Prateek Nishant
- Ocular and Orbital Neoplastic Lesions in ChildrenSantosh G Honavar, Ankita Aishwarya, Raksha Rao
- Pediatric Community OphthalmologyVadrevu K Raju, Satya S Yalla, Srinivasa R Nambula, Leela V Raju
- Pediatric Low Vision CareSarika Gopalakrishnan, TS Surendran
- Genetics and Pediatric Ocular Disorders
“The only thing worse than being blind is to have sight but no vision.”
—Hellen Keller
INTRODUCTION
In a general patients outdoor, the presence of a small child as patient is viewed with some distaste, as most of clinicians are not conversant with the techniques of eye examination of a small child. In essence, ocular examination of a small child requires patience, skill, and some talent. If one has to become proficient as a pediatric ophthalmologist, the person has to train himself to learn the techniques for a smooth and efficient examination in children. We will focus most of our attention on learning examination of infants and preschool children where the examination is difficult and requires special skills.
Sophisticated technological advances in medicine have proved to be remarkably useful in the diagnostic process, yet the well-observed history and physical examination remain a clinicians most important tools. They are venerated elements of the art of medicine, the best series of tests we have. Numerous medical anecdotes relate instances in which the examination revealed findings unrelated and unexpected from the patients complaints and concerns.
Timely eye examination and visual assessment are critical for detection of conditions that may result in irreversible visual impairment and in some cases threaten a child's life.
There is a difference in your approach when taking history/examining a small child's eyes than an older child with only vague complaints by parents. Many a times parents will bring children for just routine examination as their other sibling already has an eye problem. The approach to examination will depend upon the age, level of development, and level of understanding of the child. Inspection and observation are probably the most important part of examination.
To architect a pediatric clinic, one has to make certain changes in the environment of the clinic. For example, the waiting area should be different than a general patients area with comfortable sitting and some toys, big and small which makes the child feel at home rather than a hostile hospital atmosphere. Some institutions arrange a “play area” where the child can play during the waiting period. The waiting period should not be too long, as the child may become sleepy or hungry and would be uncooperative during examination. It is imperative that the child must be accompanied by the parents, preferably mother. The examination room should be well lighted at the beginning so that the child is not apprehensive to enter. This has an additional benefit, i.e., the clinician can “observe” the child as he/she comes to the doctor.
THE PROCESS OF EXAMINATION
Observation
Immense amount of information can be had during simple observation of a child. Do not rush to examine the child. Let the child sit comfortably on parents lap for sometime. This will give time for the child to adjust to the new surroundings and more importantly, gives time to the clinician to observe the child. Simple observation will reveal a lot of information, viz. the fixation of eyes, any obvious misalignment, nystagmus, etc. The child's behavior can also be ascertained at this juncture. An irritable child would not cooperate, may not even open eyes, and therefore the examination may be deferred for some other time, or the child may be recalled once he/she has settled. It must be remembered that a sleepy or hungry child will not cooperate and therefore it is prudent to let the child have its timely feed and then recalled after an hour or so.
History
This is most crucial and should be listened carefully from the parents, since, no information can be had from a small child. A very detailed history is not needed as you may loose precious time till the child is cooperative. Relevant and “focused” history is the key and unnecessary questions should be avoided. An old adage that “the patient is always right” does not necessarily apply here. Many a times the mother/parent are ignorant and may not understand the 4illness; the social circle around them may not perceive subtle strabismus or nystagmus as a threat to vision. The general thinking that such problems occur frequently in infants and small children and will gradually outgrow with time is deeply prevalent and the parents may not record the time when it was noticed. Sometimes, the parent will casually declare that this problem is present since “beginning”, even it may have arisen just a couple of weeks back.
History relating to perinatal birth trauma, hypoxia, febrile illness, or any such birth problem should be specifically asked. At times, it is a good idea to ask direct questions if unnecessarily time is being wasted. A slightly older child may himself narrate certain symptoms and this should be carefully noted. Many children may not complain of blurry vision—as they have learned to live with it and appropriate visual test is mandatory. In an older child, the head posture can be observed while he/she is speaking and other facial anomalies can also be observed at this time. Any rubbing of eyes and photophobia should be enquired.
The problem for which the child has been brought for should be asked from the parent or the older child himself (a child of 4–6 years is verbal and should be well communicative), and further queries in that direction should be focused. Whether the ailment is congenital or acquired should be asked and if acquired, then the age of onset. This has a bearing on the prognosis of treatment. If strabismus or nystagmus is observed, the time of onset and frequency should be asked; but if vision defect is the chief complaint, then parents need to specify whether the baby can see lights, respond to gestures, catches small toys, or very small objects. In small child with strabismus, most of times, a vague answer that strabismus is present from beginning is given. As a rule, the parents should be asked to show photographs of child since birth which will reveal the time of onset. This will greatly help in deciding management and prognosis of vision.
In older children, the child's behavior in school should be asked, especially for fatigues, headaches, vertigo, sleepiness, and regarding any specific complaint which has come from school management. Any neurological deficit should be enquired and the referring physicians notes be seen. Whether the child is on any medication, should be specifically asked and the type of medication enquired into. Many medications for any neurologic problem or gastrointestinal (GI) problem contain salts that may cause drowsiness and create unattentiveness which may be perceived as vision defect. Sudden occurrence of strabismus, diminution of vision, or diplopia needs a thorough neurologic checkup and appropriate referral should be done.
The sequence of developmental milestones should be asked and any discrepancy noted.
It is important to remember that all general and visual milestones in a premature infant are delayed and thus all parameters of visual functions are extended.
Lastly, the family history is also important. Enquiry should be done of any similar problem in other sibling, or parents or other direct relatives. Previous miscarriages should be enquired.
In short, as much of history possible should be collected in the shortest time possible; as the child may not cooperate for longer period and the actual physical examination would become difficult.
Older children are better to deal with. They can answer regarding their problems and whatever they narrate should be taken note of it. It is again prudent to develop some kind of friendship by asking about their hobbies, their school program, and about their likes and dislikes before commencing the physical exam.
Physical Examination
Children can be unpredictable, uncooperative, and noncommunicative.
Children between 1 and 2 years are most difficult to examine. In later ages they become more playful and communicative. They start knowing toys and listen to your requests.
For infants, the only source of information is their parents and examination during feeding with a bottle makes things easier. Larger and brightly colored toys are usually used to attract their attention. Noise making toys are not recommended, as movement of eyes due to “sound” gives false information.
Infants and small children should always be examined when seated on mothers lap, where they feel most comfortable and secure. There should be no hurry to finish the examination and it is advisable to keep as much distance away as possible.
Examination should be done with subdued light, as bright light can be intimidating and irritate the child and may close the lids making examination difficult.
Children over 2 years are more responsive, and therefore, calling by their name or nickname, makes them feel better. A friendly rapport should be first established with the child before embarking on any maneuver. Always begin with “noncontact” things: cover test, fixation pattern, red glow, pupillary examination, etc. Many small children get afraid by touch of a stranger, and once they get upset, it is the end of the examination. Allow the parent to show them toys of “appropriate size”, while you watch the eye movements for fixation. Appropriate size means the size of an object recommended for that particular age for testing purpose.
External Examination
The child's overall appearance and level of alertness can be judged during history taking from parents or child himself. Ocular alignment and position of head should be the first thing noted. The history will guide in which direction the physical examination should proceed including any specific tests required. The position of lids and lid aperture can be evaluated at this time.
After a general idea, the first and foremost step is to assess their visual acuity.
Gross visual acuity in infants is mostly tested for fixation and following movements, monocularly. The examiner must know the appropriate size to which the infant may hold attention. For a 1–3 months old, the “human face” is the best target while a toy of size of “thumb” suffices for 1 year infant. Objects (toys) of variable sizes fall in between these two ages. Usually in infants, slow pursuit movement arises around 4–6 months but saccadic pursuit is even present before this age. Therefore, during evaluation this has to be kept in mind (Figs. 1 and 2).
Preverbal children above 1 year of age, respond to different varieties of vision testing which has been described in chapter on vision evaluation.
FIXATION
Fixation is tested monocularly and binocularly. In monocular fixation one assesses whether the patient fixes with the fovea (central) and the quality of fixation. Each eye should be occluded in turn and the smallest possible target, appropriate for that age, that elicits the response should be used. Fixation is assessed for three different functions: (1) location (central versus (eccentric); (2) quality (good versus poor); and (3) duration (maintaining fixation). In day-to-day practice the dictum CSM is used which denotes ”central, steady and maintained”. “Central” denotes “foveal fixation”; ”steady” denotes “quality” (no nystagmus or any unsteady movements); and “maintained” proves that the fixation is maintained when the patient “follows” the movement of light across from one side to another.
Sometimes, the word FF is also used for quality maintenance which means “fix and follow”. Steady, central fixation is a good sign and the vision for that age seems to be normal. Eccentric fixation is an ominous sign and the vision is assumed to be 20/200 or less on Snellen chart. The target should be moved slowly across the visual field to assess the “quality” of fixation. The target size and distance should be documented. The “fix and follow” movements will also simultaneously show the range of both monocular and binocular eye movements. The examiner should be aware of visual milestones in an infant. Newborns have only “sporadic saccadic” movements with very poor fix and follow pattern. By 6 weeks, infants show some smooth pursuit movements with central fixation and by 8 weeks they have well-developed central and steady fixation with good fix and follow movements. It should be remembered that up to 3–4 months the smooth pursuit movement (as demonstrated by Optokinetic testing) is predominantly temporal to nasal, and this has to be kept in mind when testing for fix and follow movements. One should remember that there is a small subset of patients who have delayed maturation and may not comply to the normal testing; in these cases, it is better to recall after some months but should show definite CSM by 1 year of age.
Binocular testing compares the vision of one eye to the other. This test shows “fixation preference” of one eye and predicts diminished vision or amblyopia in the nonpreferred eye. This test has the advantage over monocular testing as even small deficiency of vision can be brought forth as the nonpreferred eye may deviate or may not follow coordinated movement along with preferred eye during “maintenance” of fixation testing. Binocular testing also has the advantage that the vision of one eye may be very low, still the eye may fix monocularly, if the target is very attractive; but the discrepancy will be elicited in binocular testing.
It is important to do monocular testing prior to binocular testing to rule out possibility of bilateral symmetric visual loss. In patients with straight eyes or microtropia (strabismus <10 pd), the fixation preference can be tested using the vertical prism test. In straight eyes, it is impossible to say which eye is fixing. The vertical prism test induces a vertical deviation and therefore allows us to examine fixation pattern. Fixation preference testing is a quick and accurate way of knowing fixation preference in cases of amblyopia due to anisometropia, unilateral ptosis, postoperative residual tropias, and other conditions that could cause unilateral amblyopia.
6Children who demonstrate poor fixation to above mentioned techniques, can be assessed by optokinetic nystagmus (OKN) drum or the Catford drum. OKN is an involuntary pursuit response to a moving target of high contrast. Since, the OKN drum consists of stripes of high contrast, the child is attracted to them even who are disinterested in other targets. The standard response is equivalent to finger counting of 3–6 ft. This is a good test to evaluate fixation as well as vision in infants and younger children.
Other ways of assessing visual function are the preferential looking tests and the pattern visual evoked potentials (PVEP). These have been already described in chapter on visual acuity.
In preverbal children, Allen's figures, Lea symbols, and HOTV charts are the standard means of evaluating the visual acuity.
Corneal reflection test: Evaluation of misalignment of eyes (strabismus) is extremely important in infants and young children. Congenital esotropias or exotropias, both have their importance with regard to vision, amblyopia, or any ominous sign. Faint leukocoria may not be evident to the parents but an obvious tropia may bring them for examination. As of strabismus per se, cover, cover-uncover testing can reveal qualitatively the type of strabismus. Though sixth nerve palsy is rare, but the author has seen cases being referred as sixth nerve palsy in infants, but actually having infantile esotropia with contracture of medial rectus. Some of these may be accommodative in nature, therefore, the author emphasizes on cycloplegic refraction under atropine and a full fundus examination. Some infants or a child may resist the cover tests; in such circumstances, the Hirschberg's corneal reflection test may be helpful. Since, this is done from a distance, the child may not be alarmed and a gross idea of strabismus can be achieved. Remember, this is a corneal “reflection” of a point light from the front surface of cornea (first Purkinjee image) and its position on both cornea will give assessment of the tropia and to some extent, quantitatively also.
PUPILLARY RESPONSES
Newborns have small, miotic pupils which increase in size to about 6–7 mm by teenage and then gradually decrease in size throughout life. It is difficult to elicit direct pupillary response due to extreme miosis and uncontrolled near reflex. Bright light should be avoided as the infant may close the lids; also effort should be made to have the baby fix at a distance toy target to avoid the near reflex. Older child can control their near reflex but still it is wise to let them look at distance. It is important to identify any “afferent pupillary defect”, especially in unilateral amblyopias and vision loss due to macular or optic nerve disease. The “swinging light test” is a good way of knowing the afferent pupillary defects as the “paradoxical” dilatation to light is an ominous sign of macular or optic nerve disease.
THE RED REFLEX
With the induction of high power bimicroscopy and other technologically advanced evaluation methods, the simple evaluation modules have taken a back seat. Nevertheless, in very young children who would be uncooperative, the “red reflex” from the fundus, has its own place to begin with. It would instantly show any media opacities and gross refractive errors and subtle misalignment.
Bruckner described a very useful test to determine these anomalies. He used a direct ophthalmoscope in a darkened room and examined the “red reflex” from the pupil simultaneously in both eyes (Fig. 3). In case of strabismus, the affected eye would show a brighter reflex with a slightly larger pupil. It has been demonstrated that as small as 5 pd of deviations can be ascertained by this method. An eye with refractive error will show a darker reflex. Amblyopia too can be detected, as when the slit beam is focused on the affected eye, nonfixation means that the eye is amblyopic. Other information like media opacities showing a dark spot or fundus anomaly showing a “pale” reflex can be obtained from Bruckner's test.
PHOTO SCREENING
This instrument-based testing for visual anomalies has gained lot of importance in recent times. This is used for large scale evaluation in general population to screen children for various visual problems. This has become a standard practice pattern for testing of ocular anomalies in developed countries, where a normal protocol is that the first testing should be done at 6 months of age, then at 3 years and finally at 5–6 years of age before the child starts formal schooling.
Purpose of early vision screening and ocular examination is to identify children who may have eye disorders which may contribute to development of severe visual impairment, amblyopia, and lack of cognitive development of a child, at 7an early age, so that effective treatment may be initiated. Although there is limited direct evidence demonstrating the effectiveness of “preschool vision screening” in reducing the prevalence of amblyopia or improving other milestones, a convincing indirect evidence supports this practice. Early detection of vision threatening refractive errors and amblyopia, helps in better chances of visual recovery.
Photo screening uses off-axis photography and photorefraction of the eye's red-reflex to evaluate refractive errors and small angle strabismus and thus identify risk factors in both eye simultaneously. A multicentric study revealed that photo screening was superior to optotype-based screening for children between ages 3 and 6 years and children who underwent their first photo screening at 2 years of age had superior eventual outcomes of treatment. Instrument-based vision screening techniques are more useful alternatives to visual acuity testing using optotype charts for very young children and children with developmental delays. But, they are not superior to quantitative vision testing with charts in children who can participate in those tests. Instrument-based vision screening detects the presence of risk factors for amblyopia, strabismus, media opacities, retinoblastoma, and retinal diseases.
REFRACTION
Determination of refractive errors is most important in all examinations. It is mandatory for not only knowing refractive error in cases of strabismus and vision impairment, but for a host of other complaints.
The clinician may be surprised to detect refractive errors in so many vague complaints by children. It should be remembered that the adequacy of cycloplegia, not dilatation, is important.
Also, the type of cycloplegic agent used according to age, the presence of any comorbidity, and color of iris should be kept in mind. The details of these drugs are listed in Table 1.
In infants: Objective refraction (retinoscopy) is indicated in all infants with defective fixation, preferential fixation, tropias, nystagmus, premature births, or any abnormality noted. The choice of cycloplegic agent is 1.0% atropine sulfate ointment, instilled twice or thrice daily for 3 days. Some infants may not show full dilatation even after this period, particularly premature or dark iris infants. In these cases, a diluted 2.5% phenylephrine can be instilled half an hour prior to examination, whence sufficient pupillary dilatation would occur. Normally sedation with phenergan (promethazine), chloral hydrate, or atarax (hydroxyzine) is sufficient in an infant for retinoscopy and fundus examination.
Toddlers do not sedate well with the above medications and where proper evaluation is necessary, general anesthesia should be used. We have now very safe agents for short-time anesthesia. Loose lenses or a lens-rack are recommended for retinoscopy. In infants, where atropine is contraindicated or previous use showed allergic reaction, a mixture of 0.5% tropicamide and 2.5% phenylephrine serves good purpose for fundoscopy and reasonably accurate retinoscopy. In preschool children, homatropine 2% is a good alternative; and in children 5 years and above, cyclopentolate 1% can be used. In author's clinical view, cyclopentolate is normally used above 5 years of age, except in Down's syndrome, cerebral palsy, or any neurological disorder, or if child showed “abnormal behavior” on previous use of this drug. In such situations, homatropine 1% or even tropicamide 1% is recommended. Children of school going age, who come with complaints of ocular asthenopia or headaches or tropias, usually esotropia, tropicamide may not be effective to unleash the full hyperopia, and a stronger cycloplegic drug is required.
For information purpose, following types of refraction techniques are available:
- Static retinoscopy, noncycloplegic, using a distant fixation target, followed by subjective correction.
- Noncycloplegic refraction using an auto-refraction equipment.
- Cycloplegic refraction using retinoscope or an Autoref.
- Mohindra near noncycloplegic retinoscopy.
8Mohindra near-retinoscopy, without use of any cycloplegia, is another objective method of estimating refractive error in infants and small children. The technique involves performing retinoscopy at near, about 50 cm, in an otherwise dark room, as the patient fixates at the retinoscope light with one eye, while the other eye is occluded. However, it is not very reliable for quantification of refractive error and the gross refractive error is usually 1.0–1.5 D on myopic side. Near-retinoscopy may be useful in the following situations:
- When frequent follow-up is required.
- When the child extremely anxious for instillation of any drops.
- When the child showed any adverse reaction to any of the above agents.
Cycloplegic retinoscopy: As a rule, “cycloplegic” retinoscopy is mandatory in all infants, preschool, and school going children, as the full and proper error can only then be established. The author uses cycloplegia till age 21 years. A common mistake is using auto-refractor in older children without cycloplegia. It should be mentally noted that children, particularly hyperopic, automatically accommodate more on autorefractor; which gives a false reading of myopia. Thus, a myopic prescription now, would exaggerate their asthenopic symptoms and a vicious circle ensues. Even in “static noncycloplegic retinoscopy”, a child may not be able to relax accommodation at distance, particularly a hyperopic child. Therefore, there is no substitute for a “cycloplegic refraction” using a proper cycloplegic agent.
Dynamic retinoscopy: Dynamic retinoscopy is a type of near retinoscopy where the child first focuses on a distant target and then at a handheld near target. The change in retinoscopic findings gives an idea of the accommodative amplitude. It is useful in determining the “accommodative lag” (insufficiency of accommodation) where the required amount of accommodation is not available for near work. The technique helps to gauge the accommodation in preverbal and school going children who cannot comply with the Royal Air Force (RAF) ruler, and who have a plethora of vague complaints. Associated with hyperopia, accommodative lag can have serious effect on a child's reading and writing capabilities.
Visual Fields
As soon as the child begins to fix steadily, say around 2 years, visual fields should be routinely tested. The easiest and quickest way is by “confrontation method” using an interesting target. Both uniocular and binocular fields should be assessed. If the child resists patching, binocular testing will also yield homonymous defects. Even in an infant, a fixation target may be used to fixate centrally and then a different attractive target may be brought in the peripheral field. Owing to good saccadic reflex, the infant may suddenly look at the peripheral target, once it is brought in the child's field of vision.
Color Vision
Although color vision is not routinely done in children but may be helpful in decreased vision of uncertain etiology and constant monitoring in progressive macular disease and optic neuropathies. More often than not, a parent may bring the child to the clinician claiming that he/she confuses between red and green pencil while during drawing for homework. Congenital red-green color defects are prevalent in about 8–10% of male population and earlier it is diagnosed, it will be better for future of the patient.
The easiest way to determine color defects are the color plates. There are two popular types of plates which are helpful in specific situations. The “Ishihara pseudoisochromatic color plates” work on the principle of “color confusion” and are useful for detection of red-green defects. Most acquired color defects show in the blue-yellow range, and will be missed on Ishihara plates, unless the defect has extended to red-green range. The advantage of this test is it can be done on illiterate patients as well as children of preverbal age, as only fingers have to be moved on the color lines.
The other test called “Richmond pseudoisochromatic plates”, previously known as “Hardy-Rand-Rittler” plates works on the principle of “color saturation” and can detect both red-green and blue-yellow defects. Unfortunately, these do not come in illiterate plates and is difficult for young children. In general, optic nerve disease will more likely show red-green defects, while retinal disease will show blue-yellow defects.
Slit-lamp Examination
Slit lamp in young children is difficult due to obvious reasons. Infants would not open eyes and bright light is not appreciated by infants and young children. Handheld slit lamps are available which are useful in a cooperative child. In infants and small children, examination under general anesthesia is the best way for microscopic, indirect ophthalmoscopic examination, and retinoscopy.
Fundus Examination
Last but not the least, an adequate fundus examination is imperative for children. For most patients, visualization of posterior pole (optic disc and macula) usually suffices. For detailed peripheral examination, general anesthesia is usually required. Infants below 1 year can be sedated and examination can be performed with slightly dim light. Young children around 2 years may not get sedated and general anesthesia may be required. Children who are older than 3 years are more cooperative and periphery can be examined in sitting position by explaining them the procedure which is more acceptable to the child.
- In all pediatric examinations, a subdued, nonscary light should be used. A small “pen-light” or a direct ophthalmoscope may suffice.
- The child should be alert and cooperative, well fed, and comfortable.
- Examination of child on parents or any known relatives lap is an ideal position.
- “Focused” history is the key prior to any physical examination. No time should be wasted as children loose interest very quickly. If necessary, direct questions should be asked relevant to the complaints.
- Observation of the child while the brief history is taken, gives enormous amount of information.
- Try to establish some sort of rapport with the child by doing a handshake or calling by nicknames are helpful and drives out the fear from the child. Toddlers and preschool children will be more cooperative with this kind of gesture.
- Always use the “age appropriate” toy target for examinations of fixation, motility testing, cover-testing, etc.
- Visual acuity, even qualitative, is important to assess.
- Examine under anesthesia, whenever necessary.
- Call the child some other time, if examination is improper due to any reason. Enquire the time of day when the child is most cheerful and try examination at that time.
- Insist on photographs—current and previous—as they are valuable in knowing the time onset of the disorder.
- Fundus examination is mandatory in cases of suspicious red-reflex, strabismus, leukocoria, etc.
- Do not alarm the parents, if some sight-threatening or life-threatening disorder is detected.
- Never spell out disaster at first meeting. And refer to a higher center, if further evaluation facilities do not exist at your center.
- There is no set protocol in the routine of examination of child. The examiner should understand the gravity of situation and mold the physical examination accordingly. The examiner should also be innovative and adaptive to attract the child's attention during examination.
SUGGESTED READING
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