Who gets a headache?
Children often complain of headaches. Most commonly, these children are aged from 2 years to 19 years, with an average age of 10 years. Migraine headaches occur in 2.7% of children by age 7 and in 10.9% of children by age 14; onset in children by age 4 is not uncommon. Headaches caused by convergence or accommodative insufficiency usually do not occur until school age and often not until third or fourth grade when the reading print becomes smaller and it takes a longer time to finish assignments.
A headache is a symptom of a problem, not a disease in its own right. The conditions listed above can be ocular causes of headaches. Headache itself does not cause medical damage, but one of the above listed conditions may cause it.
Convergence insufficiency usually occurs in the school-aged child who complains of a chronic headache, typically for several months. The child may have difficulty with learning to read; in particular, the child may hold reading material close to the face in an attempt to overcome the blurry vision. This process usually overtaxes already weak convergence amplitudes, which are a measure of a person's ability to focus both eyes simultaneously on a reading target. The problem may occur several times a week, if not daily, and may occur in school or with homework, with relief on weekends or vacations. The child does not complain of headaches that awaken the child from sleep or of headaches that occur upon awakening in the morning. Nausea and vomiting do not occur with this condition. The child may complain of double vision or may be seen closing or covering one eye, presumably to avoid double vision.
The signs and symptoms of this condition are exactly the same as convergence insufficiency. The child may complain of blurry vision or may simply complain of headache with or after reading. Sometimes, accommodative spasm may be the diagnosis. In this situation, the child becomes focused excessively at near, actually locking the eyes in this focused position. Blurry vision occurs when the eyes are raised to look in the distance.
Migraine is a common form of headache in children. Because of the frequently associated visual disturbances, children with migraine often are referred to a paediatric ophthalmologist. Migraine is classified as classic migraine, or migraine with aura; common migraine, or migraine without aura; and complicated migraine.
Migraine with Aura
Migraine with aura begins with the appearance of focal neurologic symptoms, such as numbness in a limb or facial paralysis on one side. Typically, visual symptoms last from 4 to 60 minutes (not seconds or days). Classically described, these symptoms are jagged lines of light surrounding a central blind spot that expand to the peripheral visual field. A child may describe visual symptoms as colorful, bright, flickering, turning, and moving. Some children may describe a kaleidoscope-like effect. Younger children who may not be able to describe these findings should be encouraged to draw it.
Migraine auras generally are followed by an intense, pounding headache located on one side of the head that lasts from two to four hours. The child typically will seek rest, without encouragement, in a quiet, dark room.
Migraine without Aura
This condition is not associated with preceding visual symptoms. Instead, poorly defined symptoms, generally characterized by behavioral or gastrointestinal disturbances, precede the headache attack by hours to days. The headache begins on one side of the head but often spreads to the whole head, typically lasting hours to several days. Nausea and vomiting, photophobia (avoiding light), and phonophobia (avoiding noise or even sound) are more frequent in this type of migraine than in migraine with aura.
This condition is associated with other neurologic phenomenon, including the ophthalmoplegic migraine, where the patient is unable to move an eye from side to side. Such a condition can occur in children, and it is characterized by periodic episodes of ophthalmoplegia, beginning at the peak of the headache and involving all functions of the oculomotor nerve. The headache usually occurs on the same side and is located around the orbit of the eye. The weakness may last for several weeks after the resolution of the headache.
An unusual form of complicated migraine is the Alice in Wonderland syndrome. Alterations in time and body image, as well as visual distortions, such as shrinking, enlargement, inversion, and elongation, characterize this syndrome.
Strabismus is defined as misalignment of the eyes. With this condition, the eyes can cross (esotropia), turn out (exotropia), or undergo vertical deviation (hypertropia). Any strabismus may cause headaches, with the same signs and symptoms as convergence insufficiency; however, strabismus diagnosed by the ophthalmologist differentiates the two conditions. Frequently, the parents may notice that the child covers or squints one eye with either reading or distance activity or both. Presumably, this action occurs because the child is attempting to avoid having double vision. A history of head trauma or other specific inciting event may result in nerve palsy of one of the nerves (i.e., cranial nerves III, IV, and VI) that move the eye muscles.
Refractive errors are the optical condition of the eyes that cause blurry vision, which clears by wearing glasses. Astigmatism and farsightedness are the two refractive errors that may cause a child to experience focusing problems, leading to fatigue and then headache. Astigmatism is when the front surface of the eye is shaped less like a sphere and more like an egg when one meridian is distorted. Farsightedness (hyperopia) is the optical condition when the eye is too short for the focusing system, thereby forcing the patient to excessively focus the lens of the eye (accommodate) to bring images to focus on the retina of the eye. The child often complains of headaches on school days or after long periods of reading when focusing effort has been at a maximum; no headaches occur when the child is not reading. A child with significant astigmatic error may hold reading material too close to the face simply because the words look blurry. This action, in turn, demands that the child accommodate more and converge more to be able to read. If the child holds reading material too close for too long, even normal accommodative and convergence amplitudes are inadequate to sustain long periods of reading.
Increased Intracranial Pressure
A child experiencing a headache that is caused by a brain tumor is quite significant. Classic findings include headaches that awaken the child at night, nausea and vomiting with the headache, and frequently accelerating symptoms over a relatively short time. Recurring morning headaches may be significant; however, this finding also may be related to sinus disease. Additionally, the child may complain of double vision (diplopia), jiggling vision (oscillopsia), or blurry vision. Pseudotumorcerebri is elevated pressure in the head that is not associated with an anatomic cause, such as a brain tumor or hydrocephalus. It occurs in children with prior head trauma, in children who are taking Accutane for acne, or in children who are taking prednisone, for example as part of a chemotherapy regimen. In some teenagers, this condition may occur without any reason.
A child may complain of headaches that result from an unusual diagnosis, such as albinism or nystagmus. Albinism is a specific ocular disorder caused by decreased body pigment in the skin and in the eye, where vision is decreased because the retina has a deficiency of cells. Nystagmus, which is best characterized as " jiggling eyes," results because the vision is poor or because of a primary motor instability that is congenital in nature. Nystagmus also can be caused by other entities.
The history is especially important in assessing whether the headaches occur with reading or other near effort. A child with albinism complaining of headaches may experience eyestrain by holding reading material close to the face, because of the poor vision. A child with nystagmus of any cause may hold reading material close to the face because it dampens the nystagmus (reduces the jiggling) and enlarges the print.
Diagnosis of Headache
To determine the cause of a headache relating to each of the above listed conditions, a history of the circumstances surrounding the headache and associated symptoms, a physical examination for neurological abnormalities, and an ocular examination should all be performed. The history is very important from both the parents and the child. The time course of the headache should be recorded. The frequency and the circumstances in which the headache occurs also may be important; for example, a headache may occur in school after the child reads for 15 minutes.
Associated symptoms should be explored. The pediatric ophthalmologist should be informed of other physicians who have examined the child; other tests that have been performed; other medical problems of the child; and other signs or symptoms observed by the parents, such as abnormal head positions, closing one eye, vomiting, redness, or swelling.
The eye examination is important. The pediatric ophthalmologist will check the child's visual acuity (how the child reads the eye chart) at distance and near, with one eye at a time (monocular) and with both eyes simultaneously (binocular). The child's eye alignment will be recorded in all positions of gaze (looking in every direction) and with left and right head tilt. Accommodative and convergence amplitudes will be measured, and the refractive error will be determined frequently after using dilating drops. The pediatric ophthalmologist will perform a slit lamp examination and a funduscopic examination, with close observation of the optic nerve, examining it for evidence of increased intracranial pressure.
Further diagnostic testing generally is not necessary. However, in the case of complicated migraine, glucose tolerance testing to rule out diabetes or neuroimaging (a CT scan or MRI scan of the head) to rule out serious intracranial pathology may be required. With other conditions (for example, strabismus or increased intracranial pressure), neurological testing, including neuroimaging, may be required.
Treatment of Headaches
To treat this condition, the pediatric ophthalmologist may prescribe a trial of patching with reading. The patch overcomes any strain induced by attempting to use the eyes together. If reading improves or if the headaches decline in frequency, magnitude, or duration with an eye patch, then the eyestrain induced by the effort to focus is being relieved.
Treatment for this condition is aimed at avoiding the problem or increasing reduced convergence amplitudes. If the child holds reading material too close to the face, then the reduced convergence amplitudes will cause eye fatigue/headaches in a shorter time frame. Therefore, holding reading material further from the face often is helpful. Exercises can be done to improve reduced convergence amplitudes. Convergence amplitudes are measured using a prism bar. When the amplitudes fall well below the normal range, exercises should be done. The exercises normalize reduced amplitudes. Relieving convergence insufficiency is the single most useful application of eye exercises.
Parents can begin this exercise with the aid of an orthoptist, who can train and instruct both the parents and the child. The parents should record feedback from this exercise. Two sessions of exercises, each lasting six to eight weeks, usually is recommended. The exercise can be performed at home, 15 minutes per day, with the supervision of an orthoptist once a month. The child should not have to enroll for a year of vision therapy. The end point of treatment for this condition is normalization of convergence amplitudes and/or relief of symptoms.
Measuring accommodative amplitudes is part of the eye examination. The near point of accommodation can be excessively recessed. Reading glasses are used to move the near point of accommodation close to the face. To treat this condition, it is recommended that the parents buy an inexpensive pair of over-the-counter reading glasses for the child to wear when reading. The headaches may resolve by either the placebo effect of the glasses or true accommodative insufficiency. In either case, the parent may choose to have a formal pair of bifocal glasses prescribed by the pediatric ophthalmologist.
The best treatment for migraine includes reassurance, avoidance of precipitating factors, abortive therapy, and prophylactic treatment. Abortive therapy includes rest with or without the use of acetaminophen, anti-inflammatory drugs, or antiemetics. Prophylactic treatment, including beta-blockers, calcium channel blockers, or antidepressants, may be indicated for frequent, incapacitating headaches.
Treatment is directed at alleviating strabismus with glasses (with or without a bifocal), prism glasses, occlusion (patching the eye), or surgery. When the patient has accommodative esotropia, a hyperopic glasses prescription will alleviate the crossing of the eyes and the headaches. Prism glasses are used occasionally to optically align the eyes for small amounts of strabismus. Surgery to realign the eyes is ultimately required in numerous strabismus conditions. The mechanical realignment by moving the muscles that move the eyes is often the only treatment to relieve double vision.
For a child who is farsighted (hyperopic) or nearsighted (myopic) or who has astigmatism, glasses are required. More complicated combinations of hyperopic, myopic, astigmatic, or anisometropic refractive error require formal glasses prescriptions from a pediatric ophthalmologist. Bifocal glasses rarely are needed outside of accommodative insufficiency or high accommodative convergence/accommodation ratio.
Increased Intracranial Pressure
For the conditions related to increased intracranial pressure, such as brain tumors or hydrocephalus, neurosurgical intervention is the ultimate treatment. Follow-up care with a pediatric ophthalmologist is recommended to ensure that the optic nerve returns to its normal appearance. Additionally, computerized visual field examinations are beneficial and should be performed on a periodic basis. Any ongoing loss of visual field indicates that the intracranial pressure is not being controlled; in this case, intracranial pressure monitoring is indicated.
For the child with special conditions, such as albinism and nystagmus, strong reading glasses may relieve this relative accommodative insufficieny.