Comparison of a corn silage hybrid with high cell-wall content and digestibility with a hybrid of lower cell-wall content on performance of Holstein cows.

We hypothesized that substituting a corn hybrid with high cell-wall content and high neutral detergent fiber (NDF) digestibility (HCW) for a hybrid with lower cell-wall content and lower NDF digestibility (LCW) would improve feed intake and milk production in lactating Holstein cows. There was a 3.6 percentage unit difference in NDF content and a 4.1 percentage unit difference in 30-h in vitro NDF digestion between the 2 corn hybrids. In trial 1, 40 cows (12 primiparous) ranging in milk production from 24.1 to 44.0 kg/d, following a 2-wk preliminary period, were used in a crossover design with 2-wk periods. Diets consisted of 45% corn silage (HCW or LCW), 10% alfalfa hay, and 45% concentrates. The DMI (25.4 vs. 24.2 kg/d) and 4% FCM yield (34.3 vs. 31.7 kg/d) were higher for cows fed the HCW diet compared with the LCW diet. When HCW was substituted for LCW on a DM basis, there was no relationship between pretrial milk yield (preliminary period) and subsequent response to HCW silage. In trial 2, 40 cows (8 primiparous) ranging in milk production from 20.6 to 49.0 kg/d, following a 2-wk preliminary period, were used in a crossover design with 2-wk periods. Diets consisted of the same LCW diet as trial 1 and a diet containing HCW at a concentration (40% of DM) that resulted in equal NDF content (30.8%) between the 2 diets (HCWN). The DMI (26.8 kg/d) was unaffected by diet, although there was a trend for greater DMI (% of BW) for cows fed the HCWN diet compared with LCW silage (4.24 vs. 4.12). Milk fat (3.91 vs. 3.79%) and 4% FCM yield (34.9 vs. 33.4 kg/d) were greater for cows fed HCWN vs. LCW diet. When HCW was substituted for LCW silage on an NDF basis, cows with greater milk production during the preliminary period had a greater milk response to HCW than lower-producing cows. Results of these trials supported our hypothesis that HCW corn silage results in greater DMI and milk yield than LCW silage, whether substitution occurs on a DM or NDF basis.

Early binocular visual experience may improve binocular sensory outcomes in children after surgery for congenital unilateral cataract.

PURPOSE: To compare the effect of intensive and reduced occlusion therapy regimens on binocular sensory outcomes, visual acuity, and the prevalence of strabismus in children after surgery for congenital unilateral cataract. METHODS: Two nonrandomized groups of patients were studied prospectively: (1) an intensive occlusion group (n = 29) patched 80% of waking hours were followed for a median 6.9 years and (2) a reduced occlusion group (n = 8) patched 25% to 50% of waking hours were followed for a median 4.3 years. Six subjects in the intensive group and 4 in the reduced occlusion group had secondary intraocular lenses. Two subjects in the intensive group had epikeratophakia surgery. Binocular sensory function was assessed with random dot and contour stereoacuity tests and the Worth 4-dot test. The prevalence and age at onset of strabismus were determined from the patients' charts. RESULTS: A higher proportion of subjects in the reduced occlusion group (50%) had stereoacuity or fusion compared with the intensive occlusion group (14%), a borderline significant difference (P =.08). No significant difference (P =.55) was found in median visual acuity between the intensive (20/50) and the reduced occlusion (20/55) groups. The 90% prevalence of strabismus in the intensive occlusion group was slightly higher than the 63% prevalence in the reduced occlusion group, although this difference was not significant (P =.18). CONCLUSIONS: These results suggest that a reduced occlusion protocol may be associated with better binocular sensory outcomes and a reduced prevalence of strabismus without compromising good visual acuity in children treated for congenital unilateral cataract.

Economic burden of influenza-like illness in long-term-care facilities.

Direct medical costs and medically related transportation costs incurred by patients in long-term-care facilities (LTCFs) as a result of influenza-like illness (ILI) were studied. The study was conducted from the payer's perspective. Charts were reviewed retrospectively for all patients who were residents of four Richmond, Virginia, LTCFs between January 1 and May 31, 1999. Consultant pharmacists gathered data on patient demographics, ILI status, vaccination for influenza and streptococcal pneumonia, diagnosis of asthma or chronic obstructive pulmonary disease, and utilization of health care services related to ILI. Services included the use of antimicrobials, antivirals, and respiratory drugs; emergency room visits; diagnostic tests; hospitalizations; and medically related transportation. Costs were based on average wholesale prices (for drugs) and Medicare or Medicaid reimbursement rates. Data were collected for 551 patients. Of these, 112 patients had been diagnosed with 128 cases of ILI during the study period. Twenty-two patients with ILI had 28 visits to emergency rooms, and 30 patients with ILI had 36 hospitalizations. The mean +/- S.D. cost per case of ILI was $1341 +/- $2063; inpatient hospital costs accounted for 84% of this amount. Centers for Disease Control and Prevention criteria for ILI provided a lower incidence of ILI and, consequently, a lower mean +/- S.D. cost of $968 +/- $1806 per case. ILI in patients in four LTCFs in Richmond, Virginia, generated substantial costs, the bulk of which resulted from hospitalization. A substantial percentage of the patients apparently were not immunized.

The role of anisometropia in the development of accommodative esotropia.

PURPOSE: To determine whether anisometropia increases the risk for the development of accommodative esotropia with hypermetropia. METHODS: Records of all new patients with a refractive error of +2.00 D or more (mean spherical equivalent of both eyes) over a 42-month period were reviewed. Three hundred forty-five patients were thus analyzed to determine the effect of anisometropia (>or=1 D) on the relative risk of developing accommodative esotropia and of developing unsatisfactory control with spectacles once esotropia was present. RESULTS: Anisometropia (>or=1 D) increased the relative risk of developing accommodative esotropia to 1.68 (P < .05). Anisometropia (>or=1 D) increased the relative risk for esotropia to 7.8 (P < .05) in patients with a mean spherical equivalent less than +3.00 D and increased it to 1.49 (P < .05) in patients with a mean spherical equivalent of +3.00 D or more (P = .016). In patients with esotropia and anisometropia (>or=1 D), the relative risk for a deviation that was unsatisfactorily controlled with spectacles was 1.72 (P < .05) compared with patients with esotropia but without anisometropia. Unsatisfactorily controlled esotropia was present in 33% of patients with anisometropia versus 0% of patients without anisometropia, with a mean hypermetropic spherical equivalent of less than +3.00 D (P = .003); however, anisometropia did not significantly increase the relative risk of unsatisfactory control of esotropia with spectacles in patients with a hypermetropic spherical equivalent of +3.00 D or more. Although amblyopia and anisometropia were closely associated, anisometropia increased the relative risk for esotropia to 2.14 (P < .05), even in the absence of amblyopia. CONCLUSIONS: Anisometropia (>or=1 D) is a significant risk factor for the development of accommodative esotropia, especially in patients with lower overall hypermetropia (>+3.00 D). Anisometropia also increases the risk that an accommodative esotropia will not be satisfactorily aligned with spectacles.

The association between nonstrabismic anisometropia, amblyopia, and subnormal binocularity.

PURPOSE: To determine if thresholds exist for the development of amblyopia and subnormal binocularity with various types of anisometropia and to compare these with existing guidelines for the treatment or observation of anisometropia. DESIGN: The records of all previously untreated patients evaluated for isolated refractive error during a 42-month period were reviewed to assess the association between anisometropia, amblyopia, and subnormal binocularity. PARTICIPANTS: Three hundred sixty-one (361) patients with anisometropia and 50 nonanisometropic control participants, examined over a 42-month period, with no history of treatment for refractive error, amblyopia, or other ocular pathologic characteristics were evaluated. METHODS: Uncorrected visual acuity in each eye, monofixation response, and degree of stereopsis were recorded for each patient. Patients with unequal or subnormal uncorrected visual acuity were retested with cycloplegic refraction. If the visual acuity was still abnormal, patients were retested while wearing spectacles. MAIN OUTCOME MEASURES: Degree and type of anisometropia were compared with incidence and severity of amblyopia and subnormal binocularity. RESULTS: Spherical myopic anisometropia (SMA) of more than 2 diopters (D) or spherical hypermetropic anisometropia (SHA) of more than 1 D results in a significant increase in the incidence of amblyopia and decrease in binocular function when compared with nonanisometropic patients (P = 0.05). Increasing levels of SMA and SHA beyond these thresholds result in increased incidence and severity of amblyopia. Cylindrical myopic anisometropia (CMA) or cylindrical hyperopic anisometropia (CHA) of more than 1.5 D results in a significant increase in amblyopia and a decrease in binocular function (P = 0.05). Levels of CMA and CHA more than 1.5 D result in an increased incidence and severity of amblyopia. CONCLUSIONS: This study supports existing guidelines for the treatment or observation of anisometropia and characterizes the association between the type and degree of anisometropia and the incidence and severity of amblyopia and subnormal binocularity.

Intraocular lacrimal gland choristoma involving iris and ciliary body.

PURPOSE: To describe clinical and pathologic features of an iridociliary lacrimal gland choristoma in which the diagnosis was made clinically and confirmed histopathologically. METHODS: Case report with clinical, ultrasound biomicroscopic, and histopathologic observations. RESULTS: We examined a 12-month-old male for a large iris mass that had been present since birth. We suspected it to be a lacrimal gland choristoma based on characteristic clinical features. The lesion was removed by iridocyclectomy, and the diagnosis of lacrimal gland choristoma was confirmed. CONCLUSION: Intraocular lacrimal gland choristoma has unique clinical features that should suggest the diagnosis.

The role of anisometropia in the development of accommodative esotropia.

PURPOSE: To determine if anisometropia increases the risk for the development of accommodative esotropia in hypermetropia. METHODS: Records of all new patients with a refractive error of > or = +2.00 (mean spherical equivalent [SE] of both eyes) over a 42-month period were reviewed. Three hundred forty-five (345) patients were thus analyzed to determine the effect of anisometropia (> or = 1 diopter [D]) on the relative risk of developing esodeviation and of requiring surgical correction once esodeviation was present (uncontrolled deviation). RESULTS: Anisometropia (> or = 1 D) increased the relative risk of developing accommodative esodeviation to 1.68 (P < .05). Anisometropia (> or = 1 D) increased the relative risk for esodeviation to 7.8 (P < .05) in patients with a mean SE of < 3 D and to 1.49 (P < .05) in patients with SE of > or = 3 D. This difference was significant (P = .016). In patients with esotropia and anisometropia (> or = 1 D), the relative risk for an uncontrolled deviation was 1.72 (P < .05) compared with nonanisometropic esotropic patients. Uncontrolled esodeviation was present in 33% of anisometropic patients versus 0% of nonanisometropic patients with a mean hypermetropic SE of < 3 D (P = .003); however, anisometropia did not increase the relative risk of uncontrolled esotropia in patients with SE of > or = 3 D. Although amblyopia and anisometropia were closely associated, anisometropia increased the relative risk of esodeviation to 2.14 (P < .05) even in the absence of amblyopia. CONCLUSIONS: Anisometropia (> 1 D) is a significant risk factor for the development of accommodative esodeviation, especially in patients with lower overall hypermetropia (< 3 D). Anisometropia also increases the risk that an accommodative esodeviation will not be fully eliminated with hypermetropic correction.

Complications of ocular paintball injuries in children.

PURPOSE: To evaluate the ocular complications of paintball injuries in children. METHODS: The clinical course of four children with traumatic ocular paintball injuries was evaluated. All patients underwent a complete ocular examination. Their age, injuries sustained, surgical procedure(s) performed, presence of protective eyewear at the time of injury, and final visual outcome was assessed. The presence of directly related anterior and posterior segment abnormalities were also evaluated. RESULTS: Four boys sustained traumatic paintball injuries. Average patient age was 11.25 years (range: 10-12 years). None of the children were wearing ocular or facial protection at the time of the initial injury. All patients had hyphema and traumatic cataract, and some form of retinal pathology (vitreous hemorrhage, epiretinal membrane, retinal hemorrhage, and choroidal rupture). One child had a partial-thickness corneal laceration that did not require surgical intervention. All other patients underwent ophthalmic surgery. Final visual acuity was 20/30 or better in two patients, and 20/100 or worse in the others. The cause of decreased visual acuity in these children was directly related to macular pathology. CONCLUSION: Ocular injuries resulting from paintball impact are often severe and usually occur when the participants are not wearing eye protection or this protection becomes dislodged. Treatment of these injuries is sometimes limited to an attempt to salvage what remains of useful vision. Unfortunately, most of these sports-related injuries could have been prevented if patients wore adequate eye protection when involved in this sport.

The association between anisometropia, amblyopia, and binocularity in the absence of strabismus.

PURPOSE: First, to determine if thresholds exist for the development of amblyopia and subnormal binocularity with various types of anisometropia and to confirm or refute existing guidelines for its treatment or observation. Second, to delineate any association between the degree or type of anisometropia and the depth of amblyopia and severity of binocular sensory abnormalities. METHODS: Four hundred eleven (411) patients with various levels of anisometropia, no previous therapy, and no other ocular pathology were evaluated. The effect of anisometropia (both corrected and uncorrected) on monocular acuity and binocular function was examined. RESULTS: Spherical myopic anisometropia (SMA) of > 2 diopters (D) or spherical hypermetropic anisometropia (SHA) of > 1 D results in a statistically significant increase in the incidence of amblyopia and decrease in binocular function when compared to non anisometropic patients. Increasing levels of SMA and SHA beyond these thresholds were also associated with increasing depth (and in the case of SHA, incidence as well) of amblyopia. Cylindrical myopic anisometropia (CMA) or cylindrical hyperopic anisometropia (CHA) of > 1.5 D results in a statistically significant increase in amblyopia and decrease in binocular function. A clinically significant increase in amblyopia occurs with > 1 D of CMA or CHA. Increasing levels of CMA and CHA beyond > 1 D were also associated with an increased incidence (and in the case of SMA, depth as well) of amblyopia. CONCLUSIONS: This study provides guidelines for the treatment or observation of anisometropia and confirms and characterizes the association between the type and degree of anisometropia and the incidence and severity of amblyopia and subnormal binocularity.

Early treatment of congenital unilateral cataract minimizes unequal competition.

PURPOSE: Dense congenital unilateral cataracts may compromise visual development through visual deprivation and biased interocular competition, whereas dense congenital bilateral cataracts compromise visual development primarily through visual deprivation alone. Differences in sensory deficits between the two patient groups with these disorders may reflect the specific effects of unequal competition. To determine whether early treatment (at <8 weeks of age) minimizes the adverse effects of unequal competition, grating acuity deficits during the immediate posttreatment period and contrast sensitivity deficits at 6 to 8 years of age were assessed in 29 children with histories of dense congenital unilateral or bilateral cataracts who had had treatment between 1 and 8 weeks or 12 and 30 weeks. All children maintained good to excellent compliance with optical correction and occlusion therapy. METHODS: Grating acuity was measured using a two-alternative forced-choice preferential-looking staircase protocol. Contrast thresholds at three spatial frequencies (0.38, 1.5, and 6 cyc/deg) were measured at each of two temporal frequencies (2- and 8-Hz sinusoidal counterphase modulation) using D6 grating patches. RESULTS: Grating acuity deficits in the immediate posttreatment period were similar in patients with a history of unilateral cataract (n=10) and those with a history of bilateral cataracts (n=6) when treatment was provided during the first 8 weeks of life. With later treatment, patients with a history of unilateral cataract (n=7) had significantly larger grating acuity deficits than patients with a history of bilateral cataracts (n=6). Children with a history of dense congenital unilateral cataract had similar deficits in contrast sensitivity to children with a history of bilateral cataracts when treatment was initiated during the first 8 weeks of life. When treatment was initiated later (i.e., at 12-30 weeks), patients with a history of unilateral cataract showed greater deficits in contrast sensitivity and a dependence of the amount of spatial contrast sensitivity deficit on temporal frequency than did patients with a history of bilateral cataracts. CONCLUSIONS: These findings support the hypothesis that only visual deprivation is active as an amblyogenic factor during the first weeks of life, but when unilateral deprivation is prolonged to 12 to 30 weeks, unequal competition also plays a role in amblyogenesis.

An evaluation of postabsorptive protein and amino acid metabolism in the lactating dairy cow.

The current protein system utilized in the US was formulated in 1985 with minor modifications in 1989 and has gained widespread acceptance. However, some of the assumptions that were adopted by the National Research Council (NRC) appear to be inconsistent with observational data. The marginal efficiency of conversion of absorbed protein to milk protein was assumed by NRC to be 70% until the requirement for absorbed protein was met and was 0% thereafter. The mean marginal efficiency observed for abomasal casein infusions reported in the literature and collected at the Purina Mills Research Center was 21%. Sorting the data into protein-sufficient and protein-deficient classes did not support the assumptions of 70% marginal efficiency in a deficient state and 0% marginal efficiency in the sufficient state. Analyses of nitrogen balance data and abomasal flow data and the work of Van Straalen et al. (77) indicated that energy status of the animal plays a role in determining the response to absorbed protein. Such a consideration was not included in the NRC model. The adoption of equations that describe metabolism at the organ level as opposed to the animal level would allow direct use of organ level data for parameterization and may provide better predictions. Simple representations of digestion and absorption, splanchnic metabolism, and mammary metabolism of amino acids or protein in aggregate are described. These representations could be used to improve the current system and could serve as a bridge to adoption of more complex models.

Effect of ongoing treatment of amblyopia on surgical outcome in esotropia.

PURPOSE: Classic teaching recommends completion of amblyopia therapy prior to surgical correction of esotropia. Recent reports, however, suggest that incomplete treatment does not adversely affect surgical outcome. This study assesses the effect of incompletely treated amblyopia on the success rate of bimedial rectus recession in infantile and acquired esotropia. METHODS: All patients (n = 102) with esotropia undergoing bimedial rectus recession in 1994 who met inclusion criteria were reviewed. Subjects were classified as having infantile; acquired, partially accommodative; or acquired, nonaccommodative esotropia for comparison. Amblyopia was classified as none, mild, moderate, or severe. Surgical success was defined as orthophoria +/- 8 prism diopters and was assessed at the second postoperative visit (4 to 6 weeks after surgery). Other variables studied included mean surgical age, preoperative deviation, millimeters of surgery, and amount of follow up. RESULTS: For all patients, surgical success rates were as follows: no amblyopia, 84.3% (43/51); mild amblyopia, 81.6% (31/38); and moderate amblyopia, 61.5% (8/13). All patients with severe amblyopia underwent unilateral recess/resect procedures and were excluded. Of the esotropia subgroups, a statistically significant decrease in surgical success was noted only in the infantile esotropia group with moderate amblyopia. For this group, success rates were as follows: no amblyopia, 77.1% (27/35); mild amblyopia, 81.0% (17/21); and moderate amblyopia, 16.7% (1/6), P = 0.005. CONCLUSIONS: Performing corrective surgery on patients with infantile esotropia leads to poorer surgical outcome if moderate amblyopia is present at the time of surgery. Mild amblyopia, however, does not adversely affect surgical outcome in patients with infantile esotropia. Furthermore, the presence of mild or moderate amblyopia does not appear to have an influence on surgical outcome for patients with acquired esotropia. The effect of amblyopia on sensory outcome was not studied as most patients were too young for reliable sensory testing.

A comparative microscopic analysis of the capsule of the nerve to the inferior oblique muscle.

PURPOSE: To delineate the nature of the nerve capsule to the inferior oblique muscle at birth and adulthood, and to compare it to the nerve capsules of other extraocular muscles. METHODS: Fresh autopsy specimens were obtained from a newborn and a 26 year-old male. The length of the inferior oblique nerve was analyzed with high magnification photomicroscopy and electron microscopy and compared to the nerve capsules of the adult medial, lateral, inferior and superior rectus muscles. These were also compared to the intracranial portion of the third cranial nerve of the adult specimen. RESULTS: The collagen layer of the nerve to the inferior oblique was present throughout its course. It is well developed in the newborn and comparable to the adult specimen. The nerves to the medial, inferior, lateral and superior rectus muscles are also surrounded by a similar capsule containing collagen fibers that are aligned parallel to the axon of the nerve. The intracranial portion of the third cranial nerve only has a thin fibrous capsule. CONCLUSION: The nerve capsule of the inferior oblique comprises a surrounding collagen layer, presumably to protect the nerve from stretching. This layer is well developed along the entire course of the nerve and is present from birth. The nerves to the other extraocular muscles have a similar capsule that likely serves a similar function. These findings expand current understanding of the nerves to the extraocular muscles and may be useful for improving treatments.

Delayed consecutive exotropia following 7-millimeter bilateral medial rectus recession for congenital esotropia.

The rate of delayed consecutive exotropia after bilateral 7-millimeter medial rectus recession for large angle congenital esotropia in 88 patients was 27% (24/88), larger than previously reported. The rate was 38% (8/21) in infants having surgery prior to 7 months of age, 20% (10/49) in infants undergoing surgery at 7 to 12 months of age, and 33% (6/18) in patients undergoing surgery at 13 months of age or later. The onset of consecutive exotropia averaged 26.8 months postoperatively, allowing a long period of good alignment for binocular vision to develop before exotropia surgery was required. Physicians and parents should be aware that delayed consecutive exotropia may develop several years postoperatively. Since delayed consecutive exotropia may be characteristic of the 7-millimeter recession procedure or characteristic of all patients who have had surgery for congenital esotropia, a prospective long-term study to compare the 7-millimeter procedure with the three- and four-muscle procedure would be helpful.

Unilateral lateral rectus recessions in exotropia.

For the past several years, we have been performing unilateral lateral rectus recessions in patients with small- to moderate-angle intermittent or constant exotropia. We report a 73% success rate in 45 patients undergoing 6- to 10-millimeter unilateral lateral rectus recessions in exotropia with a minimum of 6 months' follow up. The success rate increased to 89% for patients under 4 years of age. The advantages of this procedure include operating on only one eye and virtual elimination of overcorrections, thereby preventing early postoperative consecutive esotropia, which occasionally can result in amblyopia or diminished stereopsis in very young children.

Current concepts in retinopathy of prematurity.

Significant advances regarding understanding the etiology and treatment of retinopathy of prematurity have occurred in the 50 years since its discovery. Nevertheless, there is still a great deal to be learned. In spite of major technological advances in neonatal care, retinopathy of prematurity is a multi-factorial disease and probably cannot be completely prevented. Early intervention in the diagnosis and management of these infants has greatly improved their visual prognosis. Further studies may help pediatricians and neonatologists to understand and control associated risk factors. Ophthalmologists must continue to examine these patients early and follow them closely to control the associated treatable aspects of the disease, such as strabismus and amblyopia.

Office probing of congenital nasolacrimal duct obstruction.

We report the results of office nasolacrimal duct probing under topical anesthesia in 2369 eyes with symptomatic nasolacrimal duct obstruction. The overall success rate for cure by initial probing was 92%. In patients less than 9 months old, a 94% cure rate was achieved with one probing; in patients 9 months and older, the rate decreased to 84%. The decrease in success rate after 9 months was statistically significant (P less than .00001 by chi-square analysis). A majority of 180 parents of these patients surveyed said they were happy with the office procedure and preferred having the probing performed to resolve symptoms, even though they realized that the symptoms most probably would resolve by 1 year of age without it. We conclude that office probing for congenital nasolacrimal duct obstruction is a safe and effective method for treatment of symptomatic nasolacrimal duct obstruction, allowing the cost and risk of general anesthesia as well as the cost and inconvenience of prolonged medical management to be avoided.

Endophthalmitis following pediatric intraocular surgery for congenital cataracts and congenital glaucoma.

The incidence of endophthalmitis following pediatric anterior segment surgery is currently unknown. The paucity of reports of this entity has led some observers to recommend simultaneous bilateral surgery for congenital cataracts or glaucoma. In this study, we surveyed over 500 pediatric ophthalmologists and glaucoma specialists concerning their knowledge of, or involvement with, endophthalmitis following pediatric intraocular surgery. Seventeen cases of endophthalmitis were documented to occur out of 24,000 reported surgical cases. This results in an incidence estimate of 0.071%, or 7 cases per 10,000, which is similar to that recently reported following adult extracapsular cataract extraction. The presence of infection was diagnosed by the 3rd postoperative day in 82% of cases. An organism was documented by culture in 65% of cases. The organism was gram positive in all cases. Visual outcome was generally poor with 65% having no light perception. The presence of possible concurrent risk factors for postoperative endophthalmitis, including nasolacrimal duct obstruction and upper respiratory infection, was noted in 8 of the 17 cases.

Asymmetric inferior oblique overaction and its association with amblyopia in esotropia.

To evaluate the frequency of asymmetric inferior oblique overaction and its relationship to amblyopia, the authors reviewed the records of all patients who presented to Children's Hospital of Dallas with esotropia over a 2-year period. A total of 368 patients were identified and classified as infantile esotropia, acquired accommodative or partially accommodative esotropia, or acquired nonaccommodative esotropia. Two hundred forty-two patients (66%) had no amblyopia, of which 90% had symmetric inferior oblique activity. One hundred twenty-six patients (34%) had amblyopia; of these patients, 93 (74%) had symmetric inferior oblique action. Amblyopia was strongly associated with increased inferior oblique overaction in the amblyopic eye (P less than 0.001). This finding was consistent for all subgroups. The relative risk for having amblyopia as opposed to normal vision in an eye with increased inferior oblique activity relative to the contralateral eye was 5.6 to 8.6 depending on the eye. Amblyopia should be strongly suspected in patients with esotropia and asymmetric inferior oblique activity, specifically in the eye with more inferior oblique overaction.