Edited by Harold P. Koller, MD

Carolyn R. Lederman, MD White Plains, N.Y.

Hyperopia is the most common refractive state in the infant eye. Most newborns have low levels of hyperopia, with under 10 percent having greater than +3.50 D.1,2 Although high hyperopia is a risk factor in the development of amblyopia and esotropia, the optimal time to treat infants who are very hyperopic is controversial, especially if strabismus isn’t present.

This article will explore the current thinking on high hyperopia in infants in order to provide advice on the diagnosis and management of these patients.

Background

Infants’ tremendous accommodative amplitude enables them to overcome even high hyperopia easily. Because a normal eye can sustain one-half the accommodative amplitude, infants with significant hyperopia should be able to accommodate enough to produce a clear retinal image and thereby avoid amblyopia. We don’t presently know, however, if highly hyperopic eyes have subnormal levels of accommodation, which certainly could have amblyogenic potential.

A 9-month-old male with esotropia and high hyperopia. The latter is often an incidental finding in infants presenting with another problem.

A person’s refractive error changes over time.3 In the past, we thought that the infant eye was highly hyperopic and then lost hyperopia as the child aged. Two large, longitudinal studies, however, found that most infants and children have low hyperopia that increases until age 7 and decreases thereafter until the fourth decade of life.4,5 Other investigators recently showed that the refractive error of many highly hyperopic infants will decrease over the first few months of life; they found that a greater percentage of infants at 6 months of age (9 percent) have at least 4 D of meridional hyperopia2 than do infants aged 1 year (3.6 percent).6

Emmetropization, or the coordinated growth of the ocular components constituting the refractive error, leads to a reduction in a child’s refractive error. Evidence is accumulating that mechanisms sensitive to refractive error control axial length. Animal studies and mathematical models suggest that the correction of neonatal refractive errors may actually arrest or decrease the emmetropization processes that normally function.7,8,9 If so, the early treatment of high hyperopia with full or partial spectacle correction may result in the retention of high hyperopia, rather than in emmetropization over time.

Diagnosis

Oftentimes, high hyperopia is an incidental finding in infants who present with another problem. This circumstance may change if a national, early-screening program is adopted that examines individuals in either infancy or early childhood (See “Update on Vision Screening,” March 2001). In the meantime, we need to encourage physicians to refer all children with a family history of esotropia or amblyopia for an evaluation by an ophthalmologist, as there’s a higher incidence of these problems in such patients.

When taking the patient history, it’s a good idea to discuss the parents’ assessment of their child’s visual development, and bear in mind that a positive family history of esotropia is also important for assessing which infants may be at risk for high hyperopia. During the examination, if you observe abnormal head posture, such as chin down position, you’ll need to consider the possibility of an abnormal refractive error, even in the very young child.10 Look for any ocular misalignment, both pre- and post-cycloplegia, and ask about the age of onset and frequency. Although congenital esotropia is more common in infants, accommodative esotropia should be considered if the patient’s hyperopia exceeds +2.50 D.11 One note: I’ve sometimes elicited accommodative esotropia only after cycloplegia, when the patient exerts more accommodative effort; prior to cycloplegia, there may not be adequate fixation and accommodation.

Fixation is difficult to determine in many of the youngest infants, but assess vision if possible and examine the patient’s fixation preference. The Brückner test is a valuable screening method, and measuring corneal diameter (and possibly axial length) will enable you to eliminate nanophthalmos or microphthalmos as possible diagnoses. In addition, you’ll want to rule out nystagmus, which may indicate poor visual function and should prompt questioning of the parents about the age of onset and frequency. Also keep in mind that Leber’s congenital amaurosis is often associated with high hyperopia,12 as are some cases of albinism.13
I personally believe that all infants in my office deserve cycloplegic retinoscopy as a means of detecting unsuspected refractive errors. I use three doses of Alcon’s Cyclomydril (cyclopentolate 0.2% and phenylephrine 1%) in neonates, two doses of cyclopentolate 0.5% in children aged up to 6 months and one dose of cyclopentolate 1% in children aged over 6 months. I give multiple doses five minutes apart.

Management

The appropriate treatment for infants with high hyperopia depends on their ocular alignment and visual function. I don’t prescribe spectacles for highly hyperopic infants with orthophoria, no other ocular problems and normal fixation. Instead, I re-examine these patients in three months with a repeated cycloplegic refraction. If the hyperopia hasn’t diminished, or if there’s evidence of poor visual development, I’ll give spectacle correction of the cycloplegic refraction less 2 D to allow for accommodation and possible emmetropization. If, however, the hyperopia is decreasing, I’ll simply continue to follow the patient every three to four months.
I’ll also give the full cycloplegic refraction less 2 D if the infant has poor visual function for his age or an anomalous head position and orthophoria. More so in 3-year-olds, I’ve often been impressed by parents’ comments about the improvement in visual awareness of the high hyperopes with spectacle wear.

 • Anisometropia. That this condition is more common in infants than in older children implies that the emmetropization of the more ametropic eye occurs in the normal population. In 1-year-olds, if the initial amount of anisometropia exceeds 3 D, the anisometropia tends to persist, whereas lesser amounts usually equalize.14 Without the equalization of the refractive error, the more ametropic eye is at risk of developing amblyopia. The condition isn’t inevitable, however, even if hyperopic anisometropia found at 1 year of age is untreated.6

The same child with glasses to relax accommodative effort and straighten eyes. I suspect an accommodative component if the hyperopia is +2.50 D or higher and the esotropia seems to vary with visual interest. I’ll have patients wear spectacles with the full cycloplegic refraction for one month before ruling out an accommodative component.

It’s important to realize that apparent anisometropia may be due to incomplete cycloplegia in one eye. For example, suspected anisometropia may be due to better cycloplegia in an eye with a nasolacrimal duct obstruction and the drops’ better penetration due to longer surface contact time. I always make sure, therefore, that the patient’s pupils aren’t reactive after cycloplegia.

If there’s normal fixation in each eye, I’ll repeat the cycloplegic refraction in two or three months before giving spectacle correction. If the patient’s refractive error is becoming more symmetric, I’ll continue to observe him, as long as there’s no evidence of amblyopia.

I don’t patch initially. If I prescribe spectacles, my goal is the wearing of glasses at least 75 percent of waking hours. If the child resists the glasses and the anisometropia persists, I patch the less ametropic eye only one-quarter waking hours, because I’m concerned about binocular development, as well as monocular vision. More intense occlusion regimens may disrupt normal fusional development in these young brains. Moreover, research has shown fewer hours of patching to produce an equal visual outcome with better sensory function, even in infants who’ve undergone unilateral cataract surgery.15

 • Esotropia. Infants with more than +3.50 D of hyperopia at 8-9 months of age are up to 13 times more likely to develop esotropia by 4 years of age.1 For that reason, it would seem reasonable to give spectacles to infants with high hyperopia and orthophoria in order to decrease their risk of developing esotropia, and one study supports this theory.1 The finding hasn’t been corroborated by other research, however, when spectacles were given at 6 months2 or 1 year of age.16
As expected, family history plays an important role. In one study, esotropia developed in 18 percent of infants with a first degree relative with esotropia. All had Ž +4 D of hyperopia and remained highly hyperopic over time.17 Those who were highly hyperopic but lost hyperopia over time didn’t become esotropic, a finding that shows the role of emmetropization on alignment. Investigators report a higher incidence of the development of esotropia when emmetropization doesn’t occur.17,18

In an esotropic infant, I suspect an accommodative component if the hyperopia is Ž +2.50 D and the esotropia appears to vary with visual interest. Until recently, a trial of the anticholinesterase Phospholine Iodide could be used to rule out an accommodative component, but pharmacies no longer stock these drops, which are becoming increasingly difficult to obtain. As a result, I’ll prescribe spectacles with the full cycloplegic refraction in these cases. I have patients wear the spectacles full time for one month before I rule out an accommodative component.

 • Amblyopia. Researchers have found > +3.50 D of hyperopia at age
9 months to be associated with a higher risk of amblyopia (37.5 percent vs. 5.6 percent in controls).1 Other studies in older children, meanwhile, have demonstrated a significant incidence of amblyopia in children with bilateral high hyperopia.19,20

The fact that high hyperopia can lead to amblyopia should warrant the consideration of full or partial spectacle correction. As with similar attempts to decrease the development of esotropia, however, early spectacle correction at six months2 and 1 year16 hasn’t been proven to decrease the ultimate incidence of amblyopia. Moreover, treating children later doesn’t preclude a good final visual acuity. In a study in which children were first treated between 2.5 and
6.5 years of age, 85 percent achieved a Snellen acuity of 20/40 or better.19 In another study of patients treated between the ages of 8 and 141 months, 96 percent achieved 20/40 or better.20

Spectacle Wear

Prescribing glasses for infants is problematic. Parents are often highly resistant to placing their infant in spectacles, and, of course, infants object to any object on their face or head. Moreover, lenses, especially in the high plus range, are heavy for an infant, who already has a large head to body ratio. Parents also object to the distorted image that the magnification of the plus lenses creates.

Properly fitting an infant with spectacles requires an experienced optician who has available the frames designed specifically for these small faces with broad temples and flat nasal bridges. Even so, glasses often fit close to the infant’s eyes, which causes the lashes to rub on the lenses and thereby leads to further patient discomfort.

We need to keep in mind these obstacles, in addition to the continuing scientific controversy, before recommending glasses for our young patients. 

Dr. Lederman is in private practice. She is an assistant attending in ophthalmology at the Edward S. Harkness Eye Institute of New York Presbyterian Hospital.

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3. Lyle TK, ed. Worth and Chavasse’s Squint. 8th ed. Philadelphia: Blakiston, 1950.
4. Brown EVL. Net average yearly changes in refraction of atropinized eyes from birth to middle life. Arch Ophthalmol 1938;19:719-34.
5. Slataper FJ. Age norms of refraction and vision. Arch Ophthalmol 1950;43:466-81.
6. Ingram RM, Walker C, Wilson JM, et al. Prediction of amblyopia and squint by means of refraction at age 1 year. BJO 1986;70:12-5.
7. Teikari JM, et al. Impact of heredity on myopia. Hum Hered 1991;41-151-6.
8. Medina A. A model for emmetropization. Acta Ophthalmol 1987;65:565-71.
9. Hung LF, Crawford ML, Smith EL. Spectacle lenses alter eye growth and refractive status of young monkeys. Nat Med 1995;1:761-5.
10. Havertape SA, Cruz O. Abnormal head posture associated with high hyperopia. J AAPOS 1998;2:12-6.
11. Havertape SA, Whitfill CR, Cruz OA. Early onset accommodative esotropia. JPOS 1999;36:69-73.
12. Wagner RS, Caputo AR, Nelson LB, Zanoni D. High hyperopia in Leber’s congenital amaurosis. Arch Ophthalmol 1985;103:1507-9.
13. Kasmann B, Ruprecht KW. Might the refractive state in oculocutaneous albino patients be a clue for distinguishing between tyrosinase-positive and tyrosinase-negative forms of oculocutaneous albinism? Ger J Ophthalmol 1996;5:422-7.
14. Abrahamsson M, Sjostrand J. Natural history of infantile anisometropia. BJO 1996;80:860-3.
15. Jeffrey BG, Birch EE, Stager DR, et al. Early binocular visual experience may improve binocular sensory outcomes in children after surgery for congenital unilateral cataract. J AAPOS 2001;5:209-16.
16. Ingram RM, Walker C, Wilson JM, et al. A first attempt to prevent squint and amblyopia by spectacle correction of abnormal refraction from age one year. BJO 1985;69:851-3.
17. Ingram RM, Arnold PE, Dally S, Lucas J. Emmetropization, squint, and reduced visual acuity after treatment. BJO 1991;75:414-6.
18. Aurell E, Norrsell K. A longitudinal study of children with a family history of strabismus: factors determining the incidence of strabismus. BJO 1990;74:589-94.
19. Schloenleber DB, Crouch E. Bilateral hypermetropic amblyopia. JPOS 1987;24:75-7.
20. Edelman PM, Borchert MS. Visual outcome in high hypermetropia. J AAPOS 1997;1:147-50.

Further Reading
Saunders KJ. Early refractive development in humans. Surv Ophthalmol 1995;40:207-16.
Troilo D. Neonatal eye growth and emmetropization—a literature review. Eye 1992;5:154-60.