Outcome of surgery for esotropia in children with down syndrome

Neuro-Ophthalmological Manifestations in Children with Down Syndrome: Current Perspectives

Down syndrome, caused by an extra copy of all or part of chromosome 21, is the most prevalent intellectual disability of genetic origin. Among numerous comorbidities which are part of the phenotype of individuals with Down syndrome, ocular problems appear to be highly prevalent. Neuro-ophthalmological manifestations, such as ocular alignment and motility disturbances, amblyopia, hypoaccommodation or optic nerve abnormalities, and other organic ocular anomalies frequently reported in Down syndrome, may lead to an overall decrease in visual acuity. Although numerous studies have reported ocular anomalies related to Down syndrome, it remains challenging to determine the impact of each anomaly upon the decreased visual acuity, as most such individuals have more than one ocular problem. Even in children with Down syndrome and no apparent ocular defect, visual acuity has been found to be reduced compared with typically developing children. Pediatric ophthalmological examination is a critical component of a multidisciplinary approach to prevent and treat ocular complications and improve the visual outcome in children with Down syndrome. This narrative review aims to provide a better understanding of the neuro-ophthalmological manifestations and discuss the current ophthalmological management in children with Down syndrome.

Strabismus Surgery for Esotropia, Down Syndrome and Developmental Delay; Is an Altered Surgical Dose Required? A Literature Review

Background and Purpose:

There is a high rate of strabismus, in particular esotropia, in children with Down syndrome or developmental delay, which frequently requires surgical correction. A paper in 1994 advocated that the surgical dose be adjusted due to an altered response in these children. The aim of this literature review is to evaluate the available evidence to establish whether an altered surgical approach is required in either population.

Methods:

A literature review was conducted using PubMed and Web of Knowledge. Only English language papers were eligible for inclusion. The papers were collated in chronological order for analysis, and their references searched for further relevant papers. Forward citation searches were also undertaken.

Results:

A 2 × 2 comparison is made between publications on Down syndrome (in isolation) and developmental delay populations (including Down syndrome) with adjusted versus non-adjusted surgery. Published surgical success rates on esotropia from unaltered surgical doses range from 62.0%–85.7% (four papers) in the Down syndrome cohort, with none of the adjusted surgeries having a successful outcome. Surgical success rates from adjusted surgical doses in developmental delay cohort range from 37.5%–86.0% (seven papers), with one unadjusted surgical success rate of 76.0%. The results across the studies are summarised in a table and discussed.

Conclusions:

An exaggerated surgical effect in individuals with developmental delay has been reported, and this population may benefit from a reduced surgical dose. Published research does not support giving a reduced surgical dose in individuals with Down syndrome, but more research needs to be done to make a definitive conclusion.

Comparison of Surgical Success for Infantile Esotropia and Strabismus Associated with Neurological Impairment

PURPOSE

Surgery for strabismus associated with neurological impairment is assumed to have unsatisfactory results in comparison with other strabismus cases. The aim of this study is to compare the surgical success rates of infantile esotropia (IE) and strabismus associated with neurological impairment.

METHODS

The records of 103 patients that received operations for IE and strabismus associated with neurological impairment between January 1994 and May 2014 were reviewed retrospectively. The angles of deviation and surgical success rates were evaluated at preoperative, 1-month postoperative, and 24-month postoperative visits.

RESULTS

Forty-five patients received operations for strabismus associated with neurological impairment (25 patients with esotropia and 20 patients with exotropia) and 58 patients for IE. Mean preoperative angles of deviation in cases with neurological impairment were 42 prism diopters (PD) for esotropia, 44.7 PD for exotropia, and 44.4 PD for IE. One patient from each group had consecutive deviation at first visit, and at last visit, 3 patients with neurological impairment and 5 patients with IE had consecutive deviations. Surgical success rates at the end of the second year were 52% for esotropia and 50% for exotropia in patients with neurological impairment and 56.8% for IE cases.

CONCLUSION

This study was unable to find the differences between surgical success rates in IE and strabismus associated with neurological impairment.

Strabismus surgery for children with developmental delay

PURPOSE OF REVIEW

To describe recent evidence regarding the surgical approach of strabismus in children with various forms of developmental delay.

RECENT FINDINGS

There remains variability in surgical outcomes with or without dose adjustment in strabismus surgery for children with developmental delay. However, this should not deter one from performing surgery - even early surgery, as fusional potential remains possible, which can especially impact the quality of vision and quality of life in developmentally delayed children.Future prospective, comparative, long-term studies with larger sample sizes for strabismus surgery in children with developmental delay are still needed.

SUMMARY

Strabismus is one of the most common ophthalmologic findings in children with developmental delay. Surgical correction of strabismus in children with developmental delay is well tolerated and effective, although it remains slightly less predictable, which can depend on the specific type of delay or underlying neurological deficit. Careful consideration of types and severity of developmental delay and attempts to measure binocular potential can help guide the timing, dosage, and type of treatment.Reoperations tend to be more frequently encountered in this population, and this higher degree of variability should be addressed in the consent process.Considering adjusting the surgical dosage in this population, taking careful preoperative measurements, and checking for fusional potential should be taken into account when managing children with developmental delay.

Results of bilateral medial rectus recession for comitant esotropia in patients with developmental delay

PURPOSE

There is paucity of literature on surgical outcomes after strabismus surgery in patients with developmental delay. There is no consensus regarding whether standard surgical tables are applicable to these children. The goal of our study was to determine results of strabismus surgery for esotropia among these children.

METHODS

Two retrospective cohorts of patients, with developmental delay (excluding Down syndrome) and without developmental delay, who underwent bimedial recession for comitant eso-deviation between January 2005 and January 2011, meeting our criteria, were selected. Amount of surgery performed in these children was compared with standard table. This comparison gave us operated angle of deviation. This operated angle of deviation was expressed as percentage of preoperative angle of deviation to get amount of surgery performed. Response to surgery was defined as percentage of change in angle of deviation after surgery to the operated angle of deviation. Amount of surgery performed, response to surgery, and results were compared between two groups.

RESULTS

This study included 25 patients with developmental delay and 53 normal children with comitant esotropia. Age, refractive error, and preoperative angle of deviation were comparable in patients with and without developmental delay. Among patients with developmental delay, on average 72.13%±16.08 of angle of deviation was operated; response to surgery gained was 134.06%±51.62. In the control group, the average amount of surgery done was 89.08%±10.83; response gained was 89.83%±22.49. Successful outcome (±10 PD of orthophoria) was noted in 60% patients with developmental delay compared to 73.58% in control group. On average 70.67%±17.95 angle of deviation was operated in patients with developmental delay with successful outcome.

CONCLUSION

Surgical outcome in patients with developmental delay is very unpredictable. An exaggerated response to standard amounts of bimedial recession should be anticipated in these patients. Though there was no statistically significant difference, operating for 70.67%±17.95 angle of deviation is more likely to be successful.

Esotropia surgery in children with Down syndrome

PURPOSE

To evaluate postoperative alignment in children with and without Down syndrome after surgical correction of esotropia.

METHODS

The medical records of consecutive patients with Down syndrome who underwent corrective surgery for esotropia between August 1992 and July 2012 were retrospectively reviewed. Age range for eligibility was between 8 months and 17 years at surgery. The control group comprised randomly selected, age-matched patients without Down syndrome who underwent the same surgical procedure. Postoperative alignment within 10(Δ) of orthotropia at 6 months' follow-up and at the final postoperative visit was considered a successful outcome.

RESULTS

A total of 17 children with Down syndrome and 27 control subjects were included. The control group and Down syndrome group did not differ significantly in either postoperative follow-up (5.2 ± 3.2 versus 5.6 ± 5.2 years, respectively) or magnitude of deviation before surgery (40 ± 18.2(Δ) versus 39 ± 12.8(Δ), respectively). Surgical success was achieved in 76% of patients with Down syndrome and in 85% of control patients at 6 months' follow-up.

CONCLUSIONS

In this patient cohort, good surgical outcomes were achieved in children with esotropia and Down syndrome compared with those with esotropia but without Down syndrome using the same surgical technique.

Outcomes of strabismus surgery for esotropia in children with Down syndrome compared with matched controls

PURPOSE

Strabismus surgery dosages used in children with various neurodevelopmental disorders have been the subject of controversy. Few data have been reported regarding surgical results in individuals with Down syndrome (DS).

METHODS

A retrospective, case-control study was performed in which children with DS and previous bilateral medial rectus recession surgery were matched with similar control patients without DS. Surgical results were compared using a random coefficients model for repeated measurements for each group.

RESULTS

Sixteen patients with DS were matched with 16 control patients. Mean preoperative esotropia was 28.4 prism diopters (PD) in the DS group and 27.9 PD in the control group. No significant difference was found in surgical dosages between the two groups (P = .2402). Median surgical dosage was 4.4 mm in the DS group and 4.5 mm in the control group. Preoperative and 4-month and 24-month postoperative mean angles of esotropia were not different between groups (P = .8050). The 4-month postoperative mean angles of esotropia for the DS and control groups were 3.15 and 2.66 PD, respectively. The 24-month mean angles of esotropia for the DS and control groups were 7.09 and 6.60 PD, respectively.

CONCLUSION

Standard bilateral medial rectus recession surgical dosages need not be modified for individuals with DS.

Ophthalmic manifestations of mosaic Down syndrome

PURPOSE

The cognitive and physical stigmata of mosaic Down syndrome (DS) are often considered to be less severe than complete trisomy-21 DS. In contrast to complete trisomy-21 DS, the ophthalmic manifestations in mosaic DS have rarely been reported. The aim of the present study is to report clinically significant ophthalmic abnormalities in a cohort of individuals with mosaic DS.

METHODS

A prospective cross-sectional observational case series was designed to evaluate ophthalmic manifestations of mosaic DS. Individuals with mosaic DS were recruited and examined at the biennial meeting of the International Mosaic Down Syndrome Association. A medical, surgical, and ocular history was obtained. Each subject received a complete eye examination on site, including assessment of visual acuity, alignment, motility, sensory function, accommodation, anterior segment, fundus, and cycloplegic refraction.

RESULTS

Seventeen individuals with mosaic DS (mean age, 9 years; range, 6 months to 32 years) underwent eye examinations. Clinically significant refractive errors were present in 41% of the subjects, accommodative insufficiency in 59%, strabismus in 35%, nystagmus in 6%, and cataract in 6%. Ten individuals completed optotype visual acuity testing. Mean LogMAR acuity of the better eye of each subject was 0.2 (20/32 equivalent).

CONCLUSIONS

Clinically significant ophthalmic disorders are common among children and young adults with mosaic DS. Our findings support regular periodic eye examinations for these individuals.

Strabismus surgery outcome among children and young adults with Down syndrome

PURPOSE

To evaluate postoperative alignment after strabismus surgery in children with Down syndrome.

METHODS

A retrospective analysis of 15 consecutive cases of children with Down syndrome who underwent surgery for strabismus between 1990 and 2008. Follow-up was at least 6 months (range, 0.5-16 years).

RESULTS

All children underwent surgery for esotropia. The mean preoperative angle of deviation was 37.6Delta. Of the 15 children, 14 underwent surgical procedure for strabismus according to standard surgical tables. Surgical success (within 10Delta of orthophoria) was achieved in 12 of 14 children (85.7%). The remaining 2 children (14.3%) had residual esotropia.

CONCLUSIONS

Good surgical motor outcomes were achieved in children with Down syndrome after strabismus surgery following standard surgical tables. The tendency toward overcorrection reported in children with central nervous system disorders was not observed in our study. We suggest use of the same surgical calculations as used in children with normal development when treating children with Down syndrome and esotropia.