Lois Duncan

The Infant Aphakia Treatment Study: Design and Clinical Measures at Enrollment

OBJECTIVE To compare the use of contact lenses and intraocular lenses (IOLs) for the optical correction of unilateral aphakia during infancy. METHODS In a randomized, multicenter (12 sites) clinical trial, 114 infants with unilateral congenital cataracts were assigned to undergo cataract surgery with or without IOL implantation. Children randomized to IOL treatment had their residual refractive error corrected with spectacles. Children randomized to no IOL treatment had their aphakia treated with a contact lens. MAIN OUTCOME MEASURES Grating acuity at 12 months of age and HOTV visual acuity at 4 1/2 years of age. APPLICATION TO CLINICAL PRACTICE This study should determine whether either treatment for an infant with a visually significant unilateral congenital cataract results in a better visual outcome. RESULTS Enrollment began December 23, 2004, and was completed January 16, 2009. The median age at the time of cataract surgery was 1.8 months. Fifty patients were 4 to 6 weeks of age at the time of enrollment; 32, 7 weeks to 3 months of age; and the remaining 32, more than 3 to less than 7 months of age. Fifty-seven children were randomized to each treatment group. Eyes with cataracts had shorter axial lengths and steeper corneas on average than the fellow eyes. CONCLUSIONS The optimal optical treatment of aphakia in infants is unknown. However, the Infant Aphakia Treatment Study was designed to provide empirical evidence of whether optical treatment with an IOL or a contact lens after unilateral cataract surgery during infancy is associated with a better visual outcome.

Central corneal thickness in children: Racial differences (black vs. white) and correlation with measured intraocular pressure.

PurposeTo test the hypotheses that the mean central corneal thickness (CCT) of healthy black children is thinner than that of healthy white children and to confirm the relationship between increased CCT and measured intraocular pressure (IOP) in children. MethodsThis prospective observational case series included 178 eyes of 92 children aged 9 months to 17 years without anterior segment abnormalities or a clinical diagnosis of glaucoma. CCT was measured by ultrasonic pachymetry and IOP was measured by Goldmann or Tono-pen technique. ResultsThe mean CCT for the 102 eyes of 52 white children was 562±35 μm versus 543±37 μm for the 66 eyes of 35 black children (P=0.02). There was a positive relationship between CCT and IOP (P=0.0002). For every 100 μm increase in CCT, the IOP increased by 2.2±0.6 mm Hg. ConclusionsThe mean CCT of black children is thinner than that of white children. There is a positive relationship between increasing measured IOP and CCT among children with normal corneas and anterior segments. The interpretation of elevated IOP in eyes with abnormal anterior segment anatomy and thickened corneas awaits further study.

Acquired Central Corneal Thickness Increase Following Removal of Childhood Cataracts

PURPOSE To evaluate central corneal thickness (CCT) in children with congenital/developmental cataracts before and after cataract removal, to correlate CCT with corneal diameters before cataract surgery in this same group, and to evaluate CCT over time in a separate group of children who were already aphakic or pseudophakic at study entry. DESIGN Longitudinal study. METHODS Children with cataract (Group 1, with pre-cataract-removal CCT) and aphakia/pseudophakia (Group 2, presenting after cataract removal) were included. CCT measurements were performed using ultrasound pachymetry. Normal fellow eyes of unilaterally affected cases served as controls. In bilateral cases, right eyes were used for analyses. RESULTS Group 1 comprised 66 children. Before cataract surgery, unilateral cases (n = 31) showed similar CCT and strong association between the affected and fellow eyes (552.0 ± 32.9 μm vs 550.9 ± 40.4 μm, respectively; r(2) = 0.71, P = .0001). After cataract surgery, affected eyes (n = 13) showed mean CCT increase of 29.7 ± 43.1 μm (P = .03) while fellow eyes remained unchanged. Similarly, before cataract surgery, bilateral cases (n = 35) showed similar CCT between the right and left eyes. After cataract surgery, mean CCT increase was 27.4 ± 39.4 μm for first operated eyes of bilateral cases (n = 17, P = .01). Group 2 comprised 50 aphakic/pseudophakic children lacking pre-cataract-removal CCT. CCT was higher in eyes with glaucoma vs those without, at both first and last measurements (ΔCCT 58.9 ± 27.0 μm at first examination, P = .034, and 56.4 ± 27.1 μm at last examination, P = .043, respectively). There was no statistically significant CCT change over the study interval (median 28 months) for either Group 2 eyes with or those without glaucoma. CONCLUSIONS CCT in children with cataracts increases after cataract surgery while the fellow eye remains stable. This increase seems to occur early after surgery, likely remaining stable thereafter, though glaucoma can accentuate the increase.

Surgical Results in Dissociated Vertical Deviations

The effect of surgery on dissociated vertical deviations was compared in three groups of patients treated with one of the following methods: posterior fixation sutures of the superior rectus, superior rectus recession, or superior rectus recession with posterior fixation sutures. Treatment with conventional superior rectus recession combined with posterior fixation sutures (at 12 + mm) resulted in cosmetically acceptable alignment in 88% of eyes. A standard superior rectus recession alone was less dependable. Treatment with posterior fixation sutures of the superior rectus without recession was effective in only 31% of cases after long-term observation.

Stereopsis Results at 4.5 Years of Age in the Infant Aphakia Treatment Study

PURPOSE To determine whether stereopsis of infants treated for monocular cataracts varies with the type of optical correction used. DESIGN Randomized prospective clinical trial. METHODS The Infant Aphakia Treatment Study randomized 114 patients with unilateral cataracts at age 1-7 months to either primary intraocular lens (IOL) or contact lens correction. At 4.5 years of age a masked examiner assessed stereopsis on these patients using 3 different tests: (1) Frisby; (2) Randot Preschool; and (3) Titmus Fly. RESULTS Twenty-eight patients (25%) had a positive response to at least 1 of the stereopsis tests. There was no statistically significant difference in stereopsis between the 2 treatment groups: Frisby (contact lens, 6 [11%]; IOL, 7 [13%]; P = .99), Randot (contact lens, 3 [6%]; IOL, 1 [2%]; P = .62), or Titmus (contact lens, 8 [15%]; IOL, 13 [23%]; P = .34). The median age at surgery for patients with stereopsis was younger than for those without stereopsis (1.2 vs 2.4 months; P = .002). The median visual acuity for patients with stereopsis was better than for those without stereopsis (20/40 vs 20/252; P = .0003). CONCLUSION The type of optical correction did not influence stereopsis outcomes. However, 2 other factors did: age at surgery and visual acuity in the treated eye at age 4.5 years. Early surgery for unilateral congenital cataract and the presence of visual acuity better than or equal to 20/40 appear to be more important than the type of initial optical correction used for the development of stereopsis.

Central corneal thickness in children and adolescents with pediatric glaucoma and eye disorders at risk of developing glaucoma.

BACKGROUND To investigate central corneal thickness (CCT) in children with glaucoma and at risk for glaucoma. METHODS The study included 139 children with glaucoma: 66 at risk for glaucoma (ie, aphakia, aniridia, or uveitis) and 66 normal children. CCT was measured by ultrasound pachymetry and intraocular pressure (IOP) by applanation. Analysis of variance was used to compare CCT between groups. Correlation analysis assessed associations between CCT and ocular factors including spherical equivalent, cup-to-disc ratio, glaucoma medications, and number of intraocular surgeries. RESULTS CCT was significantly higher for 141 eyes with glaucoma (mean: 0.598 mm, P < .001) and 76 eyes at risk for glaucoma (mean: 0.604 mm, P = .001) than for 66 normal eyes (mean: 0.558 mm). No significant difference was observed between at-risk (P = .989) and glaucoma eyes. Eyes with aphakia (0.653 mm) and aniridia (0.639 mm) had the thickest CCT values. Thinnest CCT was found in anterior segment dysgenesis and uveitis (mean: 0.541 mm). A significant positive correlation between CCT and spherical equivalent was found for glaucoma (r = 0.413; P < .001) and at-risk (r = 0.412; P < .0003) eyes, and between CCT and intraocular surgery for at-risk eyes (P = .0066). A significant negative correlation was found between CCT and cup-to-disc ratio for glaucoma eyes (r = -0.223; P = .01). CONCLUSION This is the largest series of CCT in pediatric glaucoma and related disorders. The data suggest caution in application of standard formulas for IOP-to-CCT correction when evaluating children with glaucoma because their mean CCT values extend far beyond values reported for normal eyes.

Associated systemic and ocular disorders in patients with congenital unilateral cataracts: the Infant Aphakia Treatment Study experience.

PurposeFive-year prospective data on children enrolled in the Infant Aphakia Treatment Study (IATS) provided an opportunity to explore ocular and systemic associations in patients with a unilateral congenital cataract.MethodsInfants <7 months of age with a unilateral cataract were eligible for IATS screening. We reviewed data pertaining to the exclusion of patients as well as data collected on standardized study forms used at any time for documentation of ocular or systemic disorders.ResultsOverall, 227 infants were referred for possible enrollment. Of these, 10 had insignificant cataracts and 32 refused to participate. Of those excluded, 3 were premature, 27 had significant ocular disease (usually persistent fetal vasculature (PFV) or corneal diameter <9 mm), and 4 had systemic disorders. An additional 26 were excluded at the time of the first EUA, most often because of PFV or variants thereof. On follow-up, in the 114 enrolled patients, the following disorders were diagnosed: Stickler syndrome (1), mitochondrial disease (1), autism (1), and presumed congenital rubella syndrome (1). No patient developed a cataract in the fellow eye.DiscussionSome conditions that can feature unilateral cataracts are diagnosed at birth or very early in life, but others may be diagnosed at varying periods thereafter. PFV and its variants are the most common associated ocular findings in about a quarter of cases of unilateral congenital cataracts.ConclusionAlthough patients with a unilateral cataract may have significant associated abnormalities in the affected eye, most commonly PFV and its variants, the prevalence of associated significant systemic disease is quite low.