Stereopsis and binocular vision after surgery for unilateral infantile cataract

Stereopsis following surgery in children with congenital and developmental cataracts: A systematic review and meta-analysis

We estimated the proportion of children with stereopsis following surgery in congenital and developmental cataracts by systematic review and meta-analysis and also considered the factors influencing stereopsis, such as intervention age and presence of strabismus. Stereopsis is directly related to quality of life, and investigating its levels following cataract surgery in children may help decide the right time to intervene, particularly in the context of brain plasticity. We conducted a systematic literature search using Scopus, PubMed, and Web of Science and found 25 case series, 3 cohorts, and 3 clinical trial studies from 1/1/1995 to 31/12/2020. Study-specific proportions of stereopsis from 923 children were pooled using a random-effects model, and stratified analyses were conducted based on intervention age and pre-existing strabismus as a confounder. We appraised the risk of bias using tools published by National Institutes of Health and evaluated publication bias with funnel plots and the Egger test. The pooled proportions of stereopsis based on 8 unilateral and 6 bilateral congenital cataract studies were 0.37 (95% CIs: [0.24, 0.53]) and 0.45 (95% CIs: [0.24,0.68]) when patients with preexisting strabismus were excluded as a confounder. When the intervention age was ≤6 months, proportions in unilateral congenital cataract group significantly increased to 0.52 (95% CIs: [0.37, 0.66]; P = 0.49) compared to 0.26 (95% CIs: [0.14, 0.44]; P = 0.16) otherwise. A similar increase in proportions was found when intervention age ≤4 months. In both unilateral and bilateral congenital cataract groups, proportions increased significantly when the confounder was excluded. Overall, proportions in bilateral congenital cataracts were significantly greater than unilateral cases (irrespective of confounder). Eight unilateral and 5 bilateral developmental cataract studies resulted in pooled proportions of 0.62 (95% CIs: [0.27, 0.88] and 0.82 (95% CIs: [0.4, 0.97]), respectively. Although proportions for bilateral developmental cataracts were greater than unilateral cataracts (irrespective of confounder), results were not statistically significant. Finally, proportions in unilateral developmental cataracts were significantly greater than unilateral congenital cataracts (Z = 7.413, P = 6.173694e-14). We conclude that surgical intervention within first 4-6 months can significantly affect postoperative outcomes in unilateral congenital cataracts. Analysis of existing data does not show a significant effect of intervention age on stereopsis outcomes for developmental cataracts.

Critical Periods in Vision Revisited

For four decades, investigations of the biological basis of critical periods in the developing mammalian visual cortex were dominated by study of the consequences of altered early visual experience in cats and nonhuman primates. The neural deficits thus revealed also provided insight into the origin and neural basis of human amblyopia that in turn motivated additional studies of humans with abnormal early visual input. Recent human studies point to deficits arising from alterations in all visual cortical areas and even in nonvisual cortical regions. As the new human data accumulated in parallel with a near-complete shift toward the use of rodent animal models for the study of neural mechanisms, it is now essential to review the human data and the earlier animal data obtained from cats and monkeys to infer general conclusions and to optimize future choice of the most appropriate animal model. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Full-Diffractive Multifocal Intraocular Lens Posterior Optic Capture for Selected Pediatric Cataracts

PURPOSE

To evaluate the short-term outcomes of implantation of a full-diffractive multifocal intraocular lens (IOL) with optic capture for selected pediatric cataracts.

METHODS

In this prospective study, patients with pediatric cataract aged 3 to 14 years were selected to receive multifocal IOL (Tecnis ZMB00; Abbott Medical Optics) posterior optic capture. Visual acuity, stereopsis, visual quality, and complications were assessed.

RESULTS

Forty-five patients (66 eyes) were recruited with a follow-up of 9.09 ± 5.93 months (range: 6 to 24 months). The cataract was bilateral in 21 patients and unilateral in 24 patients. At the last follow-up visit, the mean distance-corrected distance, intermediate, and near visual acuity was 0.28 ± 0.25, 0.43 ± 0.24, and 0.39 ± 0.27 logMAR, respectively. Among the patients with bilateral cataract, postoperative corrected distance visual acuity (CDVA) was 20/40 or better in 79% (33 of 42) of the eyes and 20/20 in 26% (11 of 42) of the eyes. Of the patients with unilateral cataract, 54% (13 of 24) achieved a CDVA of 20/40 or better but none obtained a CDVA of 20/20. All patients developed stereopsis postoperatively (P < .05). There was no significant difference in modulation transfer function cut-off and Strehl ratio between the eyes with a multifocal IOL and the healthy eyes of patients with unilateral cataract (P > .05). Objective Scatter Index values were significantly better in the healthy eyes (P < .05). No posterior capsule opacification, posterior synechiae, secondary glaucoma, pigmentary IOL deposits, or IOL decentration was observed during the follow-up period.

CONCLUSIONS

Short-term follow-up results suggest full-diffractive multifocal IOL optic capture may benefit appropriately selected patients with pediatric cataract. [J Refract Surg. 2021:37(6):390-397.].

Visual outcomes of surgical and conservative treatment in children with small posterior polar cataracts and posterior lenticonus

AIM

To compare the visual outcomes of children with small (≤3 mm) posterior polar cataracts (PPC) and posterior lenticonus who had cataract extraction surgery with the visual outcomes of those who were managed conservatively.

METHODS

Children who initially had small PPC and posterior lenticonus who were followed up over 1-year period were retrospective reviewed in the study. Patients receiving surgery were compared with those receiving conservative therapy. The axial length, keratometry, refraction, best-corrected visual acuity (BCVA), and strabismus measurements were recorded. Lens morphology, i.e., the location, size, and depth of the cataract lesion, was measured with a Scheimpflug imaging system. To help control for baseline differences in the groups, patients were matched with controls by propensity score methodology.

RESULTS

The study evaluated 60 patients (30 in the surgery group and 30 in the conservative therapy group) after matching by propensity score. Patients who underwent cataract surgery showed greater BCVA improvements (0.36±0.24 logMAR) than patients who were treated without surgery (0.22±0.26 logMAR; P=0.036). Surgery was effective in patients with a rear projection length (RPL) less than 1.0 mm and a pretreatment BCVA worse than 0.52 logMAR.

CONCLUSION

Children with small PPC and posterior lenticonus who undergo cataract surgery experience greater BCVA improvements than those managed conservatively. Certain patients presenting with a RPL less than 1.0 mm and a pretreatment BCVA of 0.52 logMAR or worse may benefit from surgery.

A pilot randomized trial of contrast-rebalanced binocular treatment for deprivation amblyopia

BACKGROUND

Binocular neural architecture may be preserved in children with deprivation amblyopia due to unilateral cataract. The purpose of this study was to investigate whether a contrast-rebalanced binocular treatment, recently used with success to treat the interocular suppression and amblyopia in strabismic and anisometropic children, can contribute to rehabilitation of visual acuity in children with deprivation amblyopia secondary to monocular cataract.

METHODS

In a pilot randomized trial, 15 children (4-13 years of age) were enrolled and randomized to continue with their current treatment only (n = 7) or to continue with their current treatment and add contrast-rebalanced binocular iPad game play 5 hours/week for 4 weeks (n = 8). The primary outcome was change in visual acuity at 4 weeks.

RESULTS

Although 10 of 15 participants were patching, there was little change in visual acuity during the 3 months prior to enrollment. At the 4-week primary outcome visit, the mean improvement in visual acuity for the binocular game group was significantly greater than that for the current-treatment group (0.08 ± 0.10 logMAR vs -0.03 ± 0.05 logMAR [t_10.2 = 2.53, P = 0.03]). None of the children who had dense congenital cataract achieved improved visual acuity with binocular treatment.

CONCLUSIONS

In this study cohort, visual acuity improved over 8 weeks in children with unilateral deprivation amblyopia who played a binocular contrast-rebalanced binocular iPad game.

Occlusion for stimulus deprivation amblyopia

BACKGROUND

Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In high-income countries, most people present under the age of one year; in low- to middle-income countries, people are likely to be older at the time of presentation. The mainstay of treatment is correction of the obstruction (e.g., removal of the cataract) and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results.

OBJECTIVES

To evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes and to examine evidence of any dose-response effect and assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect.

SEARCH METHODS

We searched CENTRAL (2018, Issue 12), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Embase.com; and five other databases. We used no date or language restrictions in the electronic searches. We last searched the databases on 12 December 2018.

SELECTION CRITERIA

We planned to include randomized controlled trials (RCTs) and controlled clinical trials of participants with unilateral SDA with visual acuity worse than 0.2 LogMAR or equivalent. We specified no restrictions for inclusion based upon age, gender, ethnicity, comorbidities, medication use, or the number of participants.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified no trials that met the inclusion criteria specified in the protocol for this review.

AUTHORS' CONCLUSIONS

We found no evidence from RCTs or quasi-randomized trials on the effectiveness of any treatment for SDA. RCTs are needed in order to evaluate the safety and effectiveness of occlusion, duration of treatment, level of vision that can be realistically achieved, effects of age at onset and magnitude of visual defect, optimum occlusion regimen, and factors associated with satisfactory and unsatisfactory outcomes with the use of various interventions for SDA.

Long-term outcomes of intended undercorrection intraocular lens implantation in pediatric cataract

Purpose

To evaluate the postoperative refraction of intended undercorrection after intraocular lens (IOL) implantation in pediatric cataract patients.

Design

A cross-sectional study (data collected by retrospective chart review).

Patients and methods

The medical records of children aged under 10 years, who underwent cataract surgery with IOL implantation at the Ramathibodi Hospital between January 2000 and May 2018, were reviewed. IOL power calculations were 30%, 25%, 20%, 15% and 10% under-corrected if children were aged 6–12, 13–24, 25–36, 37–48 and 49–60 months, respectively. Two diopters (D) undercorrection was used in children aged between 5 and 8 years and one diopter undercorrection was used in children aged between 8 and 10 years. The main outcome measure was the postoperative refractive errors at the last follow-up visit.

Results

In total, 50 children (21 females and 29 males, 16 unilateral and 34 bilateral, 84 eyes) met the inclusion criteria for this study. Mean age at the time of surgery was 77.82±31.24 months. Mean follow-up time was 56.56±45.83 months. The main outcome in this study was the postoperative refractive error in children aged 7 years or more. We found 74 eyes of 44 children who were aged 7 years or more at last follow-up visit. In total, 45 eyes were myopic (−0.25 to −8.25 D) with a mean refraction of −2.26±2.16 D. A further 21 eyes were hyperopic (+0.25 to +3.25 D), with a mean refraction of +1.05±0.79 D and eight eyes were emmetropic or having only astigmatism.

Conclusion

The major postoperative refractive error at the last follow-up time was myopia. We have to adjust the IOL calculation formula to specify more undercorrection, with the aim of achieving more optimal refractive outcomes in adulthood.

Optimizing outcomes with multifocal intraocular lenses

Modern day cataract surgery is evolving from a visual restorative to a refractive procedure. The advent of multifocal intraocular lenses (MFIOLs) allows greater spectacle independence and increased quality of life postoperatively. Since the inception in 1980s, MFIOLs have undergone various technical advancements including trifocal and extended depth of vision implants more recently. A thorough preoperative workup including the patients' visual needs and inherent ocular anatomy allows us to achieve superior outcomes. This review offers a comprehensive overview of the various types of MFIOLs and principles of optimizing outcomes through a comprehensive preoperative screening and management of postoperative complications.

Strabismus surgery outcomes in the Infant Aphakia Treatment Study (IATS) at age 5 years

PURPOSE

To report strabismus surgery frequency and outcomes after monocular infantile cataract surgery with or without IOL implantation.

METHODS

The Infant Aphakia Treatment Study (IATS) is a randomized, multicenter clinical trial comparing treatment of aphakia with a primary IOL or contact lens in 114 infants with a unilateral congenital cataract. This report is a secondary outcome analysis of ocular motor data from IATS patients who underwent strabismus surgery prior to age 5 years.

RESULTS

Strabismus surgery was performed in 45 (39%) patients (contact lens group [CL], 37%; IOL group, 42% [P = 0.70]). The indications for strabismus surgery were esotropia (62%), exotropia (33%), and hypertropia (4%). Infants who underwent cataract surgery at a younger age were less likely to undergo strabismus surgery (28-48 days, 12/50 [24%]; 49-210 days, 33/64 [52%]; P = 0.0037). Of the 42 patients who underwent strabismus surgery, 14 (33%) had a postoperative distance alignment within 8^Δ of orthotropia at age 5 years. The 5-year visual acuity of children with strabismus was the same whether or not strabismus surgery had been performed (1.10 logMAR with surgery vs 1.00 without [P = 0.71]).

CONCLUSIONS

In this study cohort, cataract surgery performed in the first 6 weeks of life was associated with a reduced frequency of strabismus surgery. Strabismus surgery outcomes in this population are guarded. Surgical improvement of strabismus does not appear to influence long-term visual acuity.

Factors associated with stereopsis and a good visual acuity outcome among children in the Infant Aphakia Treatment Study

PurposeTo identify factors associated with stereopsis in children with good visual acuity after unilateral congenital cataract surgery in the Infant Aphakia Treatment Study.Patients and methodsInfants with a unilateral congenital cataract (n=114) were randomized to IOL implantation or contact lens correction after cataract surgery. At age 4.5 years, a masked examiner assessed HOTV acuity and stereopsis. Adherence to patching was assessed using 48-h recall telephone interviews and 7-day diaries throughout the first 5 years of life. Ocular motility was evaluated at age 5 years. Baseline, postoperative, and adherence findings were compared between patients with 20/40 or better acuity in their treated eyes with or without stereopsis.ResultsThirty (27%) of 112 patients who were evaluated at age 4.5 years had 20/40 or better acuity in their treated eye. Stereopsis was present on one or more tests in 15 of these 30 (50%) children. Baseline characteristics and postoperative findings did not differ between patients with or without stereopsis. Children with stereopsis were more likely to be orthotropic at distance (P=0.003) and were patched for fewer hours per day throughout the first 5 years of life and the difference increased over time (P<0.001). On average children with stereopsis were patched for 3.4 h/day during the first year of life and patching steadily decreased to 1.8 h/day by age 4 years.ConclusionAmong children with good vision following unilateral congenital cataract surgery, orthophoria and fewer hours of patching, particularly during years 2, 3, and 4, are associated with some evidence of stereopsis.

Motor skills of children with unilateral visual impairment in the Infant Aphakia Treatment Study

AIM

To assess motor functioning in children aged 4 years 6 months enrolled in the Infant Aphakia Treatment Study, and to determine contributions of visual acuity and stereopsis to measured motor skills.

METHOD

One hundred and four children (53% female) with unilateral aphakia randomized to intraocular lens or contact lens treatment were evaluated at 4 years 6 months (age range 4y 6mo-4y 11mo) for monocular recognition visual acuity, motor skills, and stereopsis by a traveling examiner masked to treatment condition. Motor skills were assessed with the Movement Assessment Battery for Children--Second Edition (MABC-2). Visual acuity was operationalized as log10 of the minimum angle of resolution (logMAR) value for treated eye, best logMAR value for either eye, and intraocular logMAR difference.

RESULTS

Student's t-tests showed no significant differences in MABC-2 scores between the intraocular lens and contact lens groups. The mean total score was low (6.43; 18th centile) compared with the normative reference group. Motor functioning was not related to visual acuity in the treated eye or to intraocular logMAR difference, but was predicted in a regression model by the better visual acuity of either eye (usually the fellow eye), even after accounting for the influence of age at surgery, examiner, orthotropic ocular alignment, and stereopsis.

INTERPRETATION

Children with unilateral congenital cataract may have delayed motor functioning at 4 years 6 months, which may adversely affect their social and academic functioning.

Sensorimotor outcomes by age 5 years after monocular cataract surgery in the Infant Aphakia Treatment Study (IATS)

PURPOSE

To evaluate sensorimotor outcomes among children in the Infant Aphakia Treatment Study (IATS).

METHODS

Secondary outcome analysis was performed in this randomized, multicenter, clinical trial comparing treatment of unilateral aphakia with a primary intraocular lens (IOL) or contact lens (CL) correction. The alignment characteristics and sensory status of children through age 5 years were evaluated.

RESULTS

In the IATS study, 91 of 112 children (81%) developed strabismus through age 5 years. Of 34 infants who were orthotropic at near 12 months after cataract surgery, at age 5 years 14 (41%) were orthotropic at distance, and 15 (44%) were orthotropic at near at age 5 years without strabismus surgery. Eight of 56 children (14%) in the CL group and 13 of 56 (23%) in the IOL group were orthotropic at distance (P = 0.33) at 5 years of age and had no history of strabismus surgery. Thirteen of 48 (27%) who underwent cataract surgery prior to 49 days of age compared to 8 of 64 (13%) who had surgery after 49 days were orthotropic (P = 0.085). Median visual acuity in the operative eye was 0.4 logMAR (20/50) for children with orthotropia or microtropia (<10(Δ)) versus 1.10 logMAR (20/252) for strabismus ≥10(Δ) (P = 0.0001). Stereopsis was detected in 12 of 21 children (57%) with orthotropia versus 16 of 89 (18%) children with strabismus (P = 0.0006).

CONCLUSIONS

IOL placement does not reduce the development of strabismus after monocular congenital cataract surgery. Improved ocular alignment by age 5 years correlated strongly with improved visual acuity and stereopsis.

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.

Occlusion for stimulus deprivation amblyopia

BACKGROUND

Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In developed countries, most patients present under the age of one year; in less developed parts of the world patients are likely to be older at the time of presentation. The mainstay of treatment is removal of the cataract and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results.

OBJECTIVES

Our objective was to evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes. Where data were available, we also planned to examine evidence of any dose response effect and to assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), the Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2013), PubMed (January 1946 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com ), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 October 2013.

SELECTION CRITERIA

We planned to include randomized and quasi-randomized controlled trials of participants with unilateral SDA with visual acuity worse than 0.2 LogMAR or equivalent. We did not specify any restrictions for inclusion based upon age, gender, ethnicity, co-morbidities, medication use, or the number of participants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study abstracts identified by the electronic searches.

MAIN RESULTS

We did not identify any trials that met the inclusion criteria specified in the protocol for this review.

AUTHORS' CONCLUSIONS

We found no evidence on the effectiveness of any treatment for SDA. Future randomized controlled trials are needed in order to evaluate the safety and effectiveness of occlusion, duration of treatment, level of vision that can be realistically achieved, effects of age at onset and magnitude of visual defect, optimum occlusion regimen, and factors associated with satisfactory and unsatisfactory outcomes with the use of various interventions for SDA.

One-year strabismus outcomes in the Infant Aphakia Treatment Study

OBJECTIVE

To evaluate the characteristics of strabismus in infants who underwent cataract surgery with and without intraocular lens (IOL) implantation.

DESIGN

Secondary outcome analysis in a prospective, randomized clinical trial.

PARTICIPANTS

The Infant Aphakia Treatment Study is a randomized, multicenter (n = 12), clinical trial comparing treatment of aphakia with a primary IOL or contact lens in 114 infants with a unilateral congenital cataract.

INTERVENTION

Infants underwent cataract surgery with or without placement of an IOL.

MAIN OUTCOME MEASURES

The proportion of patients in whom strabismus developed during the first 12 months of follow-up was calculated using the life-table method and was compared across treatment groups and age strata using a log-rank test.

RESULTS

Strabismus developed within the first 12 months of follow-up in 38 pseudophakic infants (life-table estimate, 66.7%) and 42 infants (life-table estimate, 74.5%) treated with contact lenses (P = 0.59). The younger cohort (<49 days) at the time of surgery demonstrated less strabismus (29 of 50; life-table estimate, 58.0%) than the older cohort (≥ 49 days; 51 of 64; life-table estimate, 80.0%; P<0.01).

CONCLUSIONS

Intraocular lens placement does not prevent the early development of strabismus after congenital cataract surgery. However, strabismus was less likely to develop in infants whose cataract was removed at an earlier age.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Bilateral changes in foveal structure in individuals with amblyopia

PURPOSE

To examine foveal structure in amblyopia using spectral-domain optical coherence tomography (SD-OCT).

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS AND CONTROLS

Two subject groups were recruited to the study: 85 amblyopes (34 adults, 51 children) and 110 visually normal controls (44 adults, 66 children).

METHODS

A detailed eye examination, including an SD-OCT scan, was performed in all participants. A total of 390 eyes of 195 subjects were imaged using a 3-dimensional (3D) macula scan covering a nominal 6 × 6-mm area with a resolution of 256 × 256 (65,536 axial scans). Data from the B-scans bisecting the fovea both horizontally and vertically were fitted with a mathematical model of the fovea to determine a range of foveal parameters.

MAIN OUTCOME MEASURES

Foveal thickness, foveal pit depth, and foveal pit slope.

RESULTS

Bilateral differences between the eyes of amblyopes compared with visually normal controls were found. The difference between foveal structure in amblyopic participants relative to structure in subjects with normal vision persisted even when variables such as age, ethnicity, axial length, and sex were taken into account. Amblyopes showed increased foveal thickness (+8.31 μm; P = 0.006) and a reduction in pit depth in the horizontal meridian (-10.06 μm; P = 0.005) but not in the vertical meridian (P = 0.082) when compared with subjects with normal vision. Foveal pit slopes were found to be approximately 1 degree flatter in the nasal (P = 0.033) and temporal (P = 0.014) meridians in amblyopes, but differences between amblyopes and controls in the superior (P = 0.061) and inferior (P = 0.087) meridians did not reach statistical significance. No statistically significant interocular differences were found in the foveal structure between amblyopic and fellow eyes.

CONCLUSIONS

Differences were found in the foveal structure in both eyes of amblyopes compared with subjects with normal vision. These differences consisted of increased foveal thickness, reduced pit depth when measured along the horizontal meridian, and flattening of the nasal and temporal sides of the foveal pit.

Long-term Outcomes of Undercorrection Versus Full Correction After Unilateral Intraocular Lens Implantation in Children

PURPOSE

To evaluate the impact of full correction vs undercorrection on the magnitude of the myopic shift and postoperative visual acuity after unilateral intraocular lens (IOL) implantation in children.

DESIGN

Retrospective case control study.

METHODS

The medical records of 24 children who underwent unilateral cataract surgery and IOL implantation at 2 to <6 years of age were reviewed. The patients were divided into 2 groups based on their 1-month-postoperative refraction: Group 1 (full correction) -1.0 to +1.0 diopter (D) and Group 2 (undercorrection) ≥+2.0 D. The main outcome measures included the change in refractive error per year and visual acuity for the pseudophakic eyes at last follow-up visit. The groups were compared using the independent groups t test and Wilcoxon rank sum test.

RESULTS

The mean age at surgery (Group 1, 4.2±0.9 years, n=12; Group 2, 4.5±1.0 years, n=12; P=.45) and mean follow-up (Group 1, 5.8±3.7 years; Group 2, 6.1±3.5 years; P=.69) were similar for the 2 groups. The change in refractive error (Group 1, -0.4±0.5 D/y; Group 2, -0.3±0.2 D/y; P=.70) and last median logMAR acuity (Group 1, 0.4; Group 2, 0.4; P=.54) were not significantly different between the 2 groups.

CONCLUSIONS

We did not find a significant difference in the myopic shift or the postoperative visual acuity in children aged 2 to <6 years of age following unilateral cataract surgery and IOL implantation if the initial postoperative refractive error was near emmetropia or undercorrected by 2 diopters or more.

Fixation control and eye alignment in children treated for dense congenital or developmental cataracts

BACKGROUND

Many children treated for cataracts develop strabismus and nystagmus; however, little is known about the critical period for adverse ocular motor outcomes with respect to age of onset and duration.

METHODS

Children who had undergone extraction of dense cataracts by the age of 5 years were enrolled postoperatively. Ocular alignment was assessed regularly throughout follow-up. Fixation stability and associated ocular oscillations were determined from eye movement recordings at ≥5 years old. Multivariate logistic regression was used to evaluate whether laterality (unilateral vs bilateral), age at onset, and/or duration of visual deprivation were associated with adverse ocular motor outcomes and to determine multivariate odds ratios (ORs).

RESULTS

A total of 41 children were included. Of these, 27 (66%) developed strabismus; 29 (71%) developed nystagmus. Congenital onset was associated with significant risk for strabismus (OR, 5.3; 95% CI, 1.1-34.1); infantile onset was associated with significant risk for nystagmus (OR, 13.6; 95% CI, 1.6-302). Duration >6 weeks was associated with significant risk for both strabismus (OR, 9.1; 95% CI, 1.9-54.2) and nystagmus (OR, 46.2; 95% CI, 6.0-1005). Congenital onset was associated with significant risk for interocular asymmetry in severity of nystagmus (OR, 25.0; 95% CI, 2.6-649), as was unilateral cataract (OR, 58.9; 95% CI, 5.1-2318).

CONCLUSIONS

Laterality (unilateral vs bilateral) and age at onset were significant nonmodifiable risk factors for adverse ocular motor outcomes. Duration of deprivation was a significant modifiable risk factor for adverse ocular motor outcomes. The current study demonstrated that reduced risk for nystagmus and strabismus was associated with deprivation ≤6 weeks.

Effects of brief daily periods of unrestricted vision during early monocular form deprivation on development of visual area 2

PURPOSE

Providing brief daily periods of unrestricted vision during early monocular form deprivation reduces the depth of amblyopia. To gain insights into the neural basis of the beneficial effects of this treatment, the binocular and monocular response properties of neurons were quantitatively analyzed in visual area 2 (V2) of form-deprived macaque monkeys.

METHODS

Beginning at 3 weeks of age, infant monkeys were deprived of clear vision in one eye for 12 hours every day until 21 weeks of age. They received daily periods of unrestricted vision for 0, 1, 2, or 4 hours during the form-deprivation period. After behavioral testing to measure the depth of the resulting amblyopia, microelectrode-recording experiments were conducted in V2.

RESULTS

The ocular dominance imbalance away from the affected eye was reduced in the experimental monkeys and was generally proportional to the reduction in the depth of amblyopia in individual monkeys. There were no interocular differences in the spatial properties of V2 neurons in any subject group. However, the binocular disparity sensitivity of V2 neurons was significantly higher and binocular suppression was lower in monkeys that had unrestricted vision.

CONCLUSIONS

The decrease in ocular dominance imbalance in V2 was the neuronal change most closely associated with the observed reduction in the depth of amblyopia. The results suggest that the degree to which extrastriate neurons can maintain functional connections with the deprived eye (i.e., reducing undersampling for the affected eye) is the most significant factor associated with the beneficial effects of brief periods of unrestricted vision.

Axial growth and binocular function following bilateral lensectomy and scleral fixation of an intraocular lens in nontraumatic ectopia lentis

PURPOSE

To evaluate binocular function (BF) and changes in axial length (AL) bilaterally in pseudophakic eyes of children after lensectomy and scleral fixation of an intraocular lens (IOL) for nontraumatic ectopia lentis.

METHODS

In 15 children who had undergone bilateral lensectomy and scleral fixation of an IOL for nontraumatic ectopia lentis, AL was measured preoperatively and at last follow-up, and BF was assessed at last follow-up. Axial growth was compared with the expected and observed patterns of normal eyes, and the results were compared between patients with isolated ectopia lentis and those with Marfan syndrome.

RESULTS

Ten of the 15 patients had Marfan syndrome. Mean age at surgery was 5.2 +/- 2.4 years; mean follow-up was 51.7 +/- 29.2 months. A mean axial growth rate of 0.39 mm/year during 51.7 postoperative months was greater than the expected (0.07 mm/year) or the observed (0.09-0.24 mm/year) rates in age-matched normal eyes. The axial growth rates in isolated ectopia lentis patients and Marfan patients were not significantly different (P = 0.159). Binocular fusion and stereoacuity of < or =800 seconds of arc were achieved by nine patients, and worse or no BF was achieved by the remaining six patients. These six patients were significantly more likely to have pre- or postoperative anisometropia of > or =3.0 D (66.6%) than the other nine patients (0%).

CONCLUSIONS

Because of greater than normal axial growth, more undercorrection of the IOL power is required than is usual in bilateral surgery for nontraumatic ectopia lentis. Good or moderate levels of postoperative BF were achieved in more than half of patients.

Visual outcome following the reduction or cessation of patching therapy after early unilateral cataract surgery

OBJECTIVE

To evaluate the impact on visual acuity of reducing or abandoning patching therapy during the first 6 years of life following early unilateral cataract surgery.

METHODS

We reviewed the medical records of 9 children with unilateral congenital cataracts who underwent cataract surgery when 6 weeks or younger. All had good compliance with optical correction until 6 years of age and with patching therapy until at least 12 months of age.

RESULTS

The children underwent cataract surgery at a mean (SD) age of 21.7 (9.5) days. At 12 months of age, the children were patched a mean (SD) of 6.7 (2.4) hours/d. Patching compliance declined steadily thereafter. By 6 years of age, they were only being patched a mean (SD) of 1.7 (2.0) hours/d. Four of the 9 children abandoned patching prior to the 6-year examination. Acuities improved or remained the same for 3 of these children but worsened for 1 child by 2 lines.

CONCLUSION

Our study suggests that some children who undergo early unilateral cataract surgery and are compliant with their optical correction and patching during early childhood can maintain a good visual outcome even if patching therapy is reduced or discontinued prior to their sixth birthday.

Visual function after primary posterior chamber intraocular lens implantation in pediatric unilateral cataract: stereopsis and visual acuity

Purpose

To investigate the association between binocular function and vision after cataract removal and primary posterior chamber intraocular lens (PC-IOL) implantation in children with unilateral cataract and to identify visual function differences according cataract type.

Methods

Clinical records of 2- to 6-year-old patients with unilateral cataract removal and primary PC-IOL implantation were reviewed retrospectively. Visual acuity and ocular alignment were measured. Sensory fusion was assessed with the Worth 4-dot test, and stereoacuity with the Titmus stereo test. Cataracts were classified according to cause, lens opacity location, age at onset, and presence of strabismus. Clinical characteristics of patients who obtained good visual function were identified.

Results

Forty-seven patients were included. Among 22 (46.8%) with good vision (20/40 or better), only 6 (27.3%) achieved good binocular function (the presence of fusion and 100 seconds of arc or better of stereoacuity). Visual acuity was better in eyes with good binocular function (p=0.002). No other variables were significant for achieving good binocular function.

Conclusions

The removal of unilateral cataract in a visually immature child can result in a combination of good visual acuity and binocular function. Good binocular function is closely related to good visual acuity.

Interventions for stimulus deprivation amblyopia

BACKGROUND

Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the clear passage of light, preventing clear formation of an image on the retina for example, cataract, ptosis (droopy eyelid). It is particularly severe and can be resistant to treatment and the visual prognosis is often poor. Stimulus deprivation amblyopia is rare and precise estimates of prevalence difficult to come by; it probably constitutes less than 3% of all cases of amblyopia. In developed countries most patients present under the age of one; in less developed parts of the world presentation is likely to be significantly later than this.The mainstay of treatment is patching of the better-seeing eye but regimes vary, treatment is difficult to execute and results are often disappointing.

OBJECTIVES

The objectives of this review were to evaluate the effectiveness of occlusion treatment for SDA, determine the optimum treatment regime and factors that may affect outcome.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) on The Cochrane Library (2006, Issue 1), MEDLINE (1996 to April 2006), EMBASE (1980 to April 2006) and LILACS (Latin American and Caribbean Literature on Health Sciences) (to November 2004). There were no date or language restrictions.

SELECTION CRITERIA

We aimed to include randomised and quasi-randomised controlled trials of subjects with unilateral SDA defined as worse than 0.2 LogMAR or equivalent. There were no restrictions with respect to age, gender, ethnicity, co-morbidities, medication use, and the number of participants.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study abstracts identified by the electronic searches.

MAIN RESULTS

No trials were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

It is not possible to conclude how effective treatment for SDA is or which treatment regime produces the best results. There is a need for further study in this area.

The management of posterior polar cataract: the role of patching and grading

BACKGROUND

The milder form of posterior polar cataract is often discovered late in preschool children if secondary symptoms like strabismus are not present. The question addressed in this paper is: do such children still profit from orthoptic and surgical treatment?

PATIENTS AND METHODS

This was a retrospective study of the data from 13 patients, median age 4 years (range: 1 month to 12 years), with a mean follow-up of 4 years. Four changes to the red reflex were introduced.

RESULTS

Surgery followed from two weeks to three years after starting occlusion therapy. Before therapy, the best visual acuity was 0.3 and the worst 0.06 (median 0.16). A median of four years after starting therapy, the visual acuity ranged from 0.9 to 0.4 (median 0.6).

CONCLUSION

All milder cases profited from the treatment despite its late start. An earlier discovery would improve the prognosis. In any case, however, ophthalmologists should be encouraged to try patching before resorting to surgery.

Glaucoma in children: are we making progress?

BACKGROUND

Glaucoma in children presents difficult clinical challenges. Even when appropriately treated, blindness can occur.

DESIGN

Retrospective interventional case series and literature review.

METHODS

All clinical records of children seen by the author with a diagnosis of glaucoma established before 16 years of age were reviewed from 1977 to 2003. Glaucoma was classified as primary infantile, aphakic, syndrome-related, and secondary. The best-corrected visual acuity, refractive error, configuration of the optic nerve cup, and perimetry were recorded. The intraocular pressure (IOP) for each visit was recorded. IOP measurements of 19 mm Hg or less were considered "good." The percentage of "good" readings was calculated for each eye. Representative visual acuities, refractive errors, IOP, disk configuration, and perimetry were recorded at 6, 12, 18, and 24 years of age for each patient. The admitting ophthalmologic diagnosis for each child at the Western Pennsylvania School for Blind Children was recorded from 1887 to 2003.

RESULTS

One hundred twenty-six children (204 eyes) were studied: infantile glaucoma, 52 eyes; aphakic glaucoma, 40 eyes; syndrome associated, 69 eyes; and secondary glaucoma, 43 eyes. The mean follow-up was 11.6 years (1 to 30 years). Overall, 60 (29.4%) of 204 eyes had a 6/12 (20/40) or better corrected visual acuity at the most recent visit. The percentage with this acuity remained stable throughout the follow-up period. Eyes with infantile glaucoma had the best acuity, and 40% had 6/12 (20/40) or better. Amblyopia was common and responded to treatment. Eyes with aphakic glaucoma had the worst acuity with only 10% achieving 6/12 or better. These eyes had a bimodal onset of glaucoma; eyes with an early onset had an angle closure configuration and eyes with a delayed onset had an open angle. Early cataract removal and microcornea were risk factors for glaucoma. If the IOP was maintained at 19 mm Hg or less (good) on 80% of the determinations over time, the optic nerve cup compared with the diameter of the optic nerve (C/D ratios) were stable. Eight patients had multiple, good quality, visual fields performed over 3 to 15 years. If the patients had "good" IOP on 70% of the measurements, the visual fields remained stable. A historical perspective of glaucoma control was gained by looking at the admitting diagnosis at the Western Pennsylvania School for Blind Children. From 1910 to 1970, an average of 9.2 children blind due to glaucoma were admitted each decade. From 1971 to 2003, there were only three children with glaucoma admitted over 30 years.

CONCLUSION

Removal of congenital cataracts should be delayed until 3 to 4 weeks of age. Consideration should be given for using 19 mm Hg or less to measure the success of glaucoma treatment in children. Treatment of amblyopia is as important as IOP control in children. Imaging technology such as optical coherence tomography and measurement of central corneal thickness may play an important future role in the assessment of children with suspected or known glaucoma.

Visual results after primary intraocular lens implantation or contact lens correction for aphakia in the first year of age

PURPOSE

The optimal role of intraocular lenses (IOLs) in infants remains a controversial topic. Some ophthalmologists advocate correction with a contact lens (CL), whereas others recommend an IOL correction. Our study compared visual acuity, ocular alignment, retreatment rate and binocular vision outcomes in children treated with these two methods at our clinic.

METHODS

This study included 41 children with unilateral congenital cataract who underwent cataract surgery with posterior capsulorhexis and anterior vitrectomy, coupled with (IOL group, n=18) or without (CL group, n=23) primary IOL implantation. All infants underwent the first surgery during the first 12 months of their life and they were operated on in the period from 1994 to 1999. The mean age at surgery was 3.11+/-2.65 months (range: 28 days to 11 months). All patients were prescribed the same half-time reduced occlusion therapy. Good cooperation of the parents and good compliance with patching were the necessary conditions to include a patient in the study. Between January and February 2003, the final visual acuity and binocular vision outcomes were examined.

RESULTS

The mean final visual acuity (logarithm of the minimum angle of resolution) of the operated eye was 0.43+/-0.33 for the IOL group and 0.58+/-0.39 for the CL group (p=0.14). The mean interocular difference in visual acuity was 0.22+/-0.29 for the IOL group and 0.56+/-0.31 for the CL group (p=0.042). The reoperation rate was 78% in the IOL group compared with 35% in the CL group (p=0.017). Esotropia or exotropia of more than 8 prism diopters were present in 55% of children (10/18) in the IOL group compared with 83% of children (19/23) in the CL group (p=0.039).

CONCLUSIONS

We suggest that correction of aphakia after unilateral congenital cataract surgery with primary IOL implantation results in improved visual acuity, improved binocular vision outcome and less occurrence of strabismus, but a higher rate of complications requiring reoperation. Further studies with a larger pediatric patient group are necessary to confirm the optimal treatment of aphakia after unilateral congenital cataract extraction.

Unilateral cataracts: is successful amblyopia therapy compatible with binocular vision?

BACKGROUND AND PURPOSE

Two case studies are used to illustrate the importance of balancing the postsurgical achievement of high-level visual acuity with the acquisition of stereopsis in cases of unilateral cataract. Traditional management will be reviewed and limited occlusion therapy will be discussed. A structured occlusion regime that allows for increased binocular opportunity is promoted for use upon cataract removal.

PATIENTS AND METHOD

Two cases are reviewed in which a unilateral cataract was removed and a full-time intensive patching schedule was followed.

RESULTS

Both patients reviewed have no measurable depth perception and are bothered by intractable diplopia.

CONCLUSION

Promoting good visual acuity in unilateral cataract management is the primary objective. Good visual acuity can be achieved with reduction of occlusion intensity in order to allow for some form of binocularity to develop, lowering the risk for strabismus and intractable diplopia.

Optotype acuity and re-operation rate after unilateral cataract surgery during the first 6 months of life with or without IOL implantation

AIMS

To compare optotype acuities and re-operation rates in children corrected with a contact lens (CL) compared with an intraocular lens (IOL) following unilateral cataract extraction during infancy in a non-randomised, retrospective case series.

METHODS

25 infants with a unilateral congenital cataract underwent cataract surgery with (IOL group, n = 12) or without (CL group, n = 13) IOL implantation when <7 months of age. Optotype acuities were assessed in 19 of these children at a mean age of 4.3 years (range 3.3-5.5 years). The number of re-operations were assessed in 21 children.

RESULTS

The visual acuity results were similar in the two treatment groups (p = 0.99); however, two of the four (50%) children in the IOL group compared with two of the seven (28%) children in the CL group undergoing surgery during the first 6 weeks of life had 20/40 or better visual acuity. The children in the IOL group had more re-operations than the children in the CL group (mean 1.1 v 0.36). Most of the re-operations in the IOL group were membranectomies performed during the first year of life (median 8.0 months) whereas all of the re-operations in the CL group were the implantation of a secondary IOL later in childhood (mean 2.2 years).

CONCLUSION

Optotype acuities were similar for the children corrected with a CL compared with IOL, while the children in the IOL group underwent more re-operations .

Outcome after treatment of congenital unilateral cataract

PURPOSE

To evaluate long-term functional outcome after treatment of congenital unilateral cataract.

METHODS

The records of 30 consecutive children operated on before the age of 12 months at St. Erik's Eye Hospital over a 5-year period (1991-96) were reviewed retrospectively. The patients were followed until 4-9.5 years of age. Linear Snellen visual acuity (VA), occlusion therapy compliance, and the presence of nystagmus, strabismus and other complications are reported.

RESULTS

Six children achieved VA of 0.1 or better. They were all operated on before 3 months of age. Of the 12 infants operated on before 6 weeks of age, four have VA between 0.3 and 0.4 and eight have VA of finger counting or less. Four developed severe secondary glaucoma within 6 months of cataract extraction. Two of these had persistent fetal vasculature. Three eyes developing glaucoma became amaurotic. Occlusion therapy was abandoned before the age of 2.5 years in 21 children.

CONCLUSION

Good levels of VA were achieved only in children who underwent cataract surgery before 3 months of age and who adhered to the occlusion therapy schedule. Severe secondary glaucoma developed in four out of 12 children operated on within 6 weeks. Full compliance with the occlusion therapy programme was uncommon.

Unilateral persistent hyperplastic primary vitreous: course and outcome

PURPOSE

Improved surgical techniques enable more favorable results in the management of persistent hyperplastic primary vitreous (PHPV). The purpose of our study was to evaluate the outcome of PHPV eyes managed conservatively or after surgery (with or without intraocular lens implantation).

METHODS

A total of 89 children (37 boys, 52 girls) with PHPV in one eye (mean follow-up of 6.3 +/- 5.7 years) were included. The children were subgrouped according to treatment modality. Twenty-eight (31.5%) children were managed conservatively (nonoperated). Cataract extraction combined with vitrectomy and removal of embryonic remnants was carried out in 61 eyes (68.5%). Intraocular lenses were implanted in 30 of the operated eyes (pseudophakic) and 31 eyes remained without lens (aphakic).

RESULTS

Final evaluated visual acuity in the entire group was 6/15 or better in 12.6% (11 of 87) of the eyes. A total of 11.5% (10 of 87) had a visual acuity of 6/21 to 6/60, 46.0% (40 of 87) obtained 6/90 to light perception and 26 of 87 (29.9%) had no light perception in the involved eye. The rate of no light perception was significantly lower in patients with pseudophakia (10.0%) compared to those with aphakia (43.3%) or nonoperated (37.0%) eyes (P =.009). Intraocular pressure was adequately assessed repeatedly in 72 eyes. High intraocular pressure and glaucomatous changes were observed in 7 of 31 (22.6%) patients with aphakia, 2 of 24(8.3%) patients with pseudophakia and in 2 of 17(11.8%) nonoperated eyes (P =.34). Poor cosmetic outcome was seen in 12 of 31 (38.7%) children with aphakic eyes and 5 of 30 (16.7%) children with pseudophakic eyes (P =.08). Prosthesis or cosmetic shells were needed for 8 of 31 patients with aphakia, for none of the patients with pseudophakia and for 2 of 28 of the nonoperated children (P =.003).

CONCLUSION

PHPV eyes have a potential for developing useful vision with favorable cosmetic outcome after surgery. Intraocular lens implantation may be a favorable and beneficial option for the management of children with unilateral PHPV.

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.

A comparison of grating visual acuity, strabismus, and reoperation outcomes among children with aphakia and pseudophakia after unilateral cataract surgery during the first six months of life

PURPOSE

The method of correcting aphakia after unilateral cataract extraction during infancy is controversial. Some authorities advocate correction with an intraocular lens (IOL) whereas others advocate correction with a contact lens (CL). We compared grating visual acuity, alignment, and reoperative outcomes in age-matched children treated with these 2 modalities at 5 clinical centers.

METHODS

Twenty-five infants born in 1997 or 1998 with a dense unilateral congenital cataract who had cataract surgery coupled with (IOL group, n = 12) or without (CL group, n = 13) primary IOL implantation were enrolled in this study. All patients were prescribed half-time occlusion therapy. In July 1999, their grating visual acuities, ocular alignments, and reoperation rates were assessed.

RESULTS

The mean grating visual acuity (LogMAR) for the affected eye was 0.70 +/- 0.32 for the IOL group and 0.87 +/- 0.31 for the CL group (P =.19). The mean interocular difference in grating visual acuity was 0.26 +/- 0.30 for the IOL group and 0.50 +/- 0.28 for the CL group (P =.048). The incidence of strabismus (>10 PD) was 75% in the IOL group compared with 92% in the CL group (P =.24). The incidence of reoperations was 83% in the IOL group compared with 23% in the CL group (P =.003).

CONCLUSIONS

Our preliminary data suggest that correcting aphakia after unilateral congenital cataract surgery with primary IOL implantation results in an improved visual outcome but a higher rate of complications requiring reoperation. A randomized clinical trial, the Infant Aphakia Treatment Study, is planned to further study the optimal treatment for aphakia following unilateral cataract extraction during infancy.

High levels of binocular function are achievable after removal of monocular cataracts in children before 8 years of age

OBJECTIVE

To investigate the visual acuity and binocular function results achieved in children who had monocular cataracts removed before 8 years of age.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Clinical records of 171 patients who underwent a unilateral cataract removal between January 1986 and 1996 were reviewed retrospectively. Seventy-four eyes were included in the study: 19 congenital, 11 developmental, 19 posterior lenticonus, 19 traumatic, and 6 complicated cataracts. Patients with less than 2 years of follow-up; eyes with cataracts resulting from retinoblastoma; prematurity; and those associated with dense corneal scars, lens dislocation, and persistent hyperplastic primary vitreous were excluded.

INTERVENTION

Visual acuity was measured by means of age-appropriate tests such as the fixation pattern, Allen object recognition cards, isolated optotypes with the Sheridan Gardiner test, and Snellen letters. Sensory fusion was assessed with the Worth 4-dot test, and stereo acuity was assessed with the Titmus stereo test.

MAIN OUTCOME MEASURES

Cataracts were classified regarding type, extent, age at onset, duration of the opacity, age at surgery, method of removal, development of secondary membrane, form of optical rehabilitation, and presence of strabismus. Visual acuity levels between 6/6 and 6/12 were considered "good." Fusion of the Worth 4-dot test at distance and near, and presence of stereo acuity of 100 seconds of arc or better were considered "good" binocular function. Multiple logistic regression analysis was used to define factors that correlated with achieving good visual outcome.

RESULTS

Visual acuity was 6/12 or better in 27 (36.5%) eyes. However, good binocular function was achieved in only 11 of these 27 patients. Results of univariate analysis showed that later age at onset of cataract and absence of strabismus were significant for good visual acuity and binocular function. The presence of strabismus increases the risk of not achieving good visual acuity by 5.45-fold.

CONCLUSIONS

Good visual acuity and binocular function can be achieved after removal of monocular cataracts in visually immature children. Patients with strabismus at presentation or during the follow-up period have the least chance of achieving a good sensory result.