Strabismus in Cerebral Palsy: When and Why to Operate Mary Louise Z. Collins, M.D.
ABSTRACT Cerebral palsy (CP) is the most common physical disability in children. Orthoptists and ophthalmologists who care for children with CP know that strabismus is a common feature. This paper reviews the literature on strabismus in patients with CP, and then provides summary data and recommendations for management of these patients. The incidence of strabismus in patients with CP, especially in patients with spastic diplegia, is much higher than in neurologically normal children. Esotropia is the most common ocular misalignment. CP patients with strabismus benefit from nonsurgical treatment and should be treated promptly. Strabismus surgery should be considered in CP patients for psychosocial reasons as well as for potential successful ocular realignment and restoration of binocular vision. The literature is lacking in a long-term natural history study, prospective strabismus surgery studies, and long-term outcome studies of strabismus management in patients with CP.
INTRODUCTION Cerebral palsy (CP) is a group of disorders that has features in common. One of the early definitions of CP—“an unchangFrom the Department of Ophthalmology, Greater Baltimore Medical Center, Baltimore, Maryland. Requests for reprints should be addressed to: Mary Louise Z. Collins, M.D., Greater Baltimore Medical Center, 6569 N. Charles St. #505, Baltimore, MD 21204. Presented as part of a Symposium of the Joint Meeting of the American Orthoptic Council, the American Association of Certified Orthoptists, and the American Academy of Ophthalmology, New Orleans, Louisiana, November 17, 2013.
ing disorder of movement and posture appearing early in life and due to a nonprogressive disorder of the brain, the result of interference during development”1 —is still applicable today. CP is classified according to the type of motor abnormality (spastic, athetoid, ataxic, and atonic) and the number of limbs affected (monoplegia, diplegia, hemiplegia, and quadriplegia). It is the most common physical disability in children, and recent studies show the prevalence in the United States to be 3.1 out of every 1,000 8-year-old children. Spastic cerebral palsy is the most common type (76.9%), and 58.2% of the children
© 2014 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448
American Orthoptic Journal
17
STRABISMUS IN CEREBRAL PALSY
identified as having any type of cerebral palsy could walk independently.2 Starting in the mid-twentieth century, as survival rates of children with CP increased, interest in the visual and ocular manifestations expanded. Amblyopia, strabismus, cortical visual impairment, visual field defects, and other abnormalities of the visual and sensory motor pathways have been reported at higher rates in children with CP than in neurologically normal children.3-11 This paper will review the present literature on strabismus in patients with CP with special attention to surgical management. CEREBRAL PALSY AND STRABISMUS Studies that report the frequency of strabismus in patients with CP show a range of 20-90% of patients with most studies in the range of 40-60%.3, 6, 9, 12, 13, 14, 15, 16, 17 In all studies that looked at the incidence of strabismus by type of CP, strabismus was most common in patients with the spastic type, and less common in athetoid and ataxic.6, 13, 18 In most reports, esotropia was more common than exotropia,3, 6, 8, 9, 12, 16, 18, 19 ranging from 1.5:1 ET > XT16 to one study showing 85% of the children with strabismus having esotropia.9 These studies did not classify patients by age. Another consistent finding among the studies was that diplegics had a greater chance of strabismus than either hemiplegics or quadriplegics.3, 12, 13 Binocular vision was evaluated in only one study and revealed that more than 50% of patients with CP had no evidence of binocular vision. Those with higher degrees of motor impairment from CP had less chance of binocular vision.3 TREATMENT IN THE LITERATURE Treatment of strabismus in patients with CP has received relatively little attention until recently. A complete search of PubMed® listings for strabismus surgery in patients with CP reveals very few articles.
18
Guibor wrote in 1953, “early operative interventions before 8 years of age is usually unsuccessful . . . and when early surgery is done, repeated operations are the rule.”14 Others echoed this sentiment regarding the unpredictability of long-term results from strabismus surgery in patients with cerebral palsy.6, 15, 16 In 1976, Levy and Cassin wrote, “conservative nonsurgical therapy has been employed early . . . because of observation that spontaneous recovery may occur in younger children.”16 This issue of spontaneous recovery, and even the development of spontaneous exotropia in previously esotropic patients is primarily anecdotal, since review of the literature did not reveal any well-designed, longterm natural history study of strabismus in patients with CP. In the 1970s, authors began to discuss more about the nonsurgical management of strabismus in patients with CP, including treatment of amblyopia and the accommodative component of esotropia. Hiles reported that 80% of accommodative esotropia patients were orthophoric with refractive correction alone.18 Most authors now agree that medical management of strabismus in patients with CP is indicated—“attempted eradication of the ocular deviation in order to allow the development or restoration of bifoveal fixation where possible.”15 In the mid-1970s, discussion of surgical management of strabismus in patients with CP began to appear in the literature. Hiles et al. reported the largest series of patients, 234 children with strabismus who had conventional surgery and had an overall success rate of 90% with satisfactory alignment after an average of 4 years follow-up.18 In addition to the potential benefit of restoring binocular vision, most authors agree that restoration of normal ocular alignment is important for psychosocial reasons.6, 8, 13, 18 Ghasia argued for treatment of strabismus in these patients, since the “psychosocial harm would be ex-
Volume 64, 2014
COLLINS
pected to be heightened in cerebral palsy children, who may be ridiculed or ostracized both for their motor handicaps and for strabismus.”20 Search of the literature did not reveal any prospective studies on the surgical treatment of strabismus in patients with CP. There have been several more recent retrospective studies looking at the surgical management of these patients. Ghasia et al. reviewed the management of fifty patients with CP who underwent standard dose strabismus surgery, and was the only one to report results in terms of effect on binocular vision.20 This study reported a mean follow-up period of 4.1 years. Optimal results (
ABSTRACT Cerebral palsy (CP) is the most common physical disability in children. Orthoptists and ophthalmologists who care for children with CP know that strabismus is a common feature. This paper reviews the literature on strabismus in patients with CP, and then provides summary data and recommendations for management of these patients. The incidence of strabismus in patients with CP, especially in patients with spastic diplegia, is much higher than in neurologically normal children. Esotropia is the most common ocular misalignment. CP patients with strabismus benefit from nonsurgical treatment and should be treated promptly. Strabismus surgery should be considered in CP patients for psychosocial reasons as well as for potential successful ocular realignment and restoration of binocular vision. The literature is lacking in a long-term natural history study, prospective strabismus surgery studies, and long-term outcome studies of strabismus management in patients with CP.
INTRODUCTION Cerebral palsy (CP) is a group of disorders that has features in common. One of the early definitions of CP—“an unchangFrom the Department of Ophthalmology, Greater Baltimore Medical Center, Baltimore, Maryland. Requests for reprints should be addressed to: Mary Louise Z. Collins, M.D., Greater Baltimore Medical Center, 6569 N. Charles St. #505, Baltimore, MD 21204. Presented as part of a Symposium of the Joint Meeting of the American Orthoptic Council, the American Association of Certified Orthoptists, and the American Academy of Ophthalmology, New Orleans, Louisiana, November 17, 2013.
ing disorder of movement and posture appearing early in life and due to a nonprogressive disorder of the brain, the result of interference during development”1 —is still applicable today. CP is classified according to the type of motor abnormality (spastic, athetoid, ataxic, and atonic) and the number of limbs affected (monoplegia, diplegia, hemiplegia, and quadriplegia). It is the most common physical disability in children, and recent studies show the prevalence in the United States to be 3.1 out of every 1,000 8-year-old children. Spastic cerebral palsy is the most common type (76.9%), and 58.2% of the children
© 2014 Board of Regents of the University of Wisconsin System, American Orthoptic Journal, Volume 64, 2014, ISSN 0065-955X, E-ISSN 1553-4448
American Orthoptic Journal
17
STRABISMUS IN CEREBRAL PALSY
identified as having any type of cerebral palsy could walk independently.2 Starting in the mid-twentieth century, as survival rates of children with CP increased, interest in the visual and ocular manifestations expanded. Amblyopia, strabismus, cortical visual impairment, visual field defects, and other abnormalities of the visual and sensory motor pathways have been reported at higher rates in children with CP than in neurologically normal children.3-11 This paper will review the present literature on strabismus in patients with CP with special attention to surgical management. CEREBRAL PALSY AND STRABISMUS Studies that report the frequency of strabismus in patients with CP show a range of 20-90% of patients with most studies in the range of 40-60%.3, 6, 9, 12, 13, 14, 15, 16, 17 In all studies that looked at the incidence of strabismus by type of CP, strabismus was most common in patients with the spastic type, and less common in athetoid and ataxic.6, 13, 18 In most reports, esotropia was more common than exotropia,3, 6, 8, 9, 12, 16, 18, 19 ranging from 1.5:1 ET > XT16 to one study showing 85% of the children with strabismus having esotropia.9 These studies did not classify patients by age. Another consistent finding among the studies was that diplegics had a greater chance of strabismus than either hemiplegics or quadriplegics.3, 12, 13 Binocular vision was evaluated in only one study and revealed that more than 50% of patients with CP had no evidence of binocular vision. Those with higher degrees of motor impairment from CP had less chance of binocular vision.3 TREATMENT IN THE LITERATURE Treatment of strabismus in patients with CP has received relatively little attention until recently. A complete search of PubMed® listings for strabismus surgery in patients with CP reveals very few articles.
18
Guibor wrote in 1953, “early operative interventions before 8 years of age is usually unsuccessful . . . and when early surgery is done, repeated operations are the rule.”14 Others echoed this sentiment regarding the unpredictability of long-term results from strabismus surgery in patients with cerebral palsy.6, 15, 16 In 1976, Levy and Cassin wrote, “conservative nonsurgical therapy has been employed early . . . because of observation that spontaneous recovery may occur in younger children.”16 This issue of spontaneous recovery, and even the development of spontaneous exotropia in previously esotropic patients is primarily anecdotal, since review of the literature did not reveal any well-designed, longterm natural history study of strabismus in patients with CP. In the 1970s, authors began to discuss more about the nonsurgical management of strabismus in patients with CP, including treatment of amblyopia and the accommodative component of esotropia. Hiles reported that 80% of accommodative esotropia patients were orthophoric with refractive correction alone.18 Most authors now agree that medical management of strabismus in patients with CP is indicated—“attempted eradication of the ocular deviation in order to allow the development or restoration of bifoveal fixation where possible.”15 In the mid-1970s, discussion of surgical management of strabismus in patients with CP began to appear in the literature. Hiles et al. reported the largest series of patients, 234 children with strabismus who had conventional surgery and had an overall success rate of 90% with satisfactory alignment after an average of 4 years follow-up.18 In addition to the potential benefit of restoring binocular vision, most authors agree that restoration of normal ocular alignment is important for psychosocial reasons.6, 8, 13, 18 Ghasia argued for treatment of strabismus in these patients, since the “psychosocial harm would be ex-
Volume 64, 2014
COLLINS
pected to be heightened in cerebral palsy children, who may be ridiculed or ostracized both for their motor handicaps and for strabismus.”20 Search of the literature did not reveal any prospective studies on the surgical treatment of strabismus in patients with CP. There have been several more recent retrospective studies looking at the surgical management of these patients. Ghasia et al. reviewed the management of fifty patients with CP who underwent standard dose strabismus surgery, and was the only one to report results in terms of effect on binocular vision.20 This study reported a mean follow-up period of 4.1 years. Optimal results (
