Publications by authors named "Simon T Ko"

15 Publications

  • Page 1 of 1

Two-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 2 Report.

Ophthalmology 2020 07 21;127(7):910-919. Epub 2019 Dec 21.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.

Purpose: To evaluate the efficacy and safety of 0.05%, 0.025%, and 0.01% atropine eye drops over 2 years to determine which is the optimal concentration for longer-term myopia control.

Design: Randomized, double-masked trial extended from the Low-Concentration Atropine for Myopia Progression (LAMP) Study.

Participants: Three hundred eighty-three of 438 children (87%) aged 4 to 12 years with myopia of at least -1.0 diopter (D) originally randomized to receive atropine 0.05%, 0.025%, 0.01%, or placebo once daily in both eyes in the LAMP phase 1 study were continued in this extended trial (phase 2).

Methods: Children in the placebo group (phase 1) were switched to receive 0.05% atropine from the beginning of the second-year follow-up, whereas those in the 0.05%, 0.025%, and 0.01% atropine groups continued with the same regimen. Cycloplegic refraction, axial length (AL), accommodation amplitude, photopic and mesopic pupil diameter, and best-corrected visual acuity were measured at 4-month intervals.

Main Outcome Measures: Changes in spherical equivalent (SE) and AL and their differences between groups.

Results: Over the 2-year period, the mean SE progression was 0.55±0.86 D, 0.85±0.73 D, and 1.12±0.85 D in the 0.05%, 0.025%, and 0.01% atropine groups, respectively (P = 0.015, P < 0.001, and P = 0.02, respectively, for pairwise comparisons), with mean AL changes over 2 years of 0.39±0.35 mm, 0.50±0.33 mm, and 0.59±0.38 mm (P = 0.04, P < 0.001, and P = 0.10, respectively). Compared with the first year, the second-year efficacy of 0.05% and 0.025% atropine remained similar (P >0.1), but improved mildly in the 0.01% atropine group (P = 0.04). For the phase 1 placebo group, the myopia progression was reduced significantly after switching to 0.05% atropine (SE change, 0.18 D in second year vs. 0.82 D in first year [P < 0.001]; AL elongated 0.15 mm in second year vs. 0.43 mm in first year [P < 0.001]). Accommodation loss and change in pupil size in all concentrations remained similar to the first-year results and were well tolerated. Visual acuity and vision-related quality of life remained unaffected.

Conclusions: Over 2 years, the efficacy of 0.05% atropine observed was double that observed with 0.01% atropine, and it remained the optimal concentration among the studied atropine concentrations in slowing myopia progression.
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http://dx.doi.org/10.1016/j.ophtha.2019.12.011DOI Listing
July 2020

Upper Cranial Nerve Involvement and Immunoglobulin G4-Related Optic Neuropathy.

Ophthalmology 2020 05 26;127(5):699-703. Epub 2019 Nov 26.

Department of Ophthalmology and Visual Sciences, Princess of Wales Hospital, Wales, United Kingdom; Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong, Hong Kong. Electronic address:

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http://dx.doi.org/10.1016/j.ophtha.2019.11.015DOI Listing
May 2020

Choroidal thickness in thyroid-associated orbitopathy.

Clin Exp Ophthalmol 2019 Sep 20;47(7):918-924. Epub 2019 May 20.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

Importance: To investigate the choroidal thickness (CT) in patients with thyroid-associated orbitopathy (TAO).

Background: To compare CT of TAO patients and healthy subjects.

Design: Prospective cross-sectional study in a public hospital.

Participants: One hundred and four eyes of 52 TAO patients and 52 eyes of 26 healthy subjects.

Methods: CT was measured with enhanced-depth imaging optical coherence tomography (EDI-OCT) at the subfoveal, macular and peripapillary regions. Multivariate linear regression was used to evaluate the associations of subfoveal CT with systemic and ocular variables among TAO eyes.

Main Outcome Measures: CT of both groups.

Results: CT of eyes with TAO was significantly increased at the subfoveal region, 1 and 2 mm from the fovea nasally, temporally and superiorly, and 1 mm inferior to the fovea (all P < .05). No significant difference was found in CT at 2 mm inferior to the fovea (P = .094) and all four quadrants of the peripapillary region (superior, P = .096; nasal, P = .732; inferior, P = .179; temporal, P = .052). Among TAO eyes, thinner subfoveal choroid was associated with worsening exophthalmos (P = .043), poorer visual acuity (P = .017), increasing age (P = .040) and axial length (P < .001). There was no association between CT and clinical activity score (P = .239).

Conclusions And Relevance: TAO patients showed thicker choroid than controls over the macula, but not the peripapillary regions. Thinner subfoveal choroid was associated with worsening exophthalmos and poorer vision. EDI-OCT can monitor choroidal vascular changes associated with TAO and its complications.
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http://dx.doi.org/10.1111/ceo.13525DOI Listing
September 2019

Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control.

Ophthalmology 2019 01 6;126(1):113-124. Epub 2018 Jul 6.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

Purpose: Low-concentration atropine is an emerging therapy for myopia progression, but its efficacy and optimal concentration remain uncertain. Our study aimed to evaluate the efficacy and safety of low-concentration atropine eye drops at 0.05%, 0.025%, and 0.01% compared with placebo over a 1-year period.

Design: Randomized, placebo-controlled, double-masked trial.

Participants: A total of 438 children aged 4 to 12 years with myopia of at least -1.0 diopter (D) and astigmatism of -2.5 D or less.

Methods: Participants were randomly assigned in a 1:1:1:1 ratio to receive 0.05%, 0.025%, and 0.01% atropine eye drops, or placebo eye drop, respectively, once nightly to both eyes for 1 year. Cycloplegic refraction, axial length (AL), accommodation amplitude, pupil diameter, and best-corrected visual acuity were measured at baseline, 2 weeks, 4 months, 8 months, and 12 months. Visual Function Questionnaire was administered at the 1-year visit.

Main Outcome Measures: Changes in spherical equivalent (SE) and AL were measured, and their differences among groups were compared using generalized estimating equation.

Results: After 1 year, the mean SE change was -0.27±0.61 D, -0.46±0.45 D, -0.59±0.61 D, and -0.81±0.53 D in the 0.05%, 0.025%, and 0.01% atropine groups, and placebo groups, respectively (P < 0.001), with a respective mean increase in AL of 0.20±0.25 mm, 0.29±0.20 mm, 0.36±0.29 mm, and 0.41±0.22 mm (P < 0.001). The accommodation amplitude was reduced by 1.98±2.82 D, 1.61±2.61 D, 0.26±3.04 D, and 0.32±2.91 D, respectively (P < 0.001). The pupil sizes under photopic and mesopic conditions were increased respectively by 1.03±1.02 mm and 0.58±0.63 mm in the 0.05% atropine group, 0.76±0.90 mm and 0.43±0.61 mm in the 0.025% atropine group, 0.49±0.80 mm and 0.23±0.46 mm in the 0.01% atropine group, and 0.13±1.07 mm and 0.02±0.55 mm in the placebo group (P < 0.001). Visual acuity and vision-related quality of life were not affected in each group.

Conclusions: The 0.05%, 0.025%, and 0.01% atropine eye drops reduced myopia progression along a concentration-dependent response. All concentrations were well tolerated without an adverse effect on vision-related quality of life. Of the 3 concentrations used, 0.05% atropine was most effective in controlling SE progression and AL elongation over a period of 1 year.
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http://dx.doi.org/10.1016/j.ophtha.2018.05.029DOI Listing
January 2019

Association of antenatal steroid and risk of retinopathy of prematurity: a systematic review and meta-analysis.

Br J Ophthalmol 2018 10 9;102(10):1336-1341. Epub 2018 Apr 9.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong

Background: Retinopathy of prematurity (ROP) is one of the leading causes of childhood blindness. Use of antenatal steroid can reduce neonatal morbidity and mortality in preterm births, but its effect on ROP remained controversial. We aim to determine the association between antenatal steroid and risk of ROP by a systematic review and meta-analysis.

Methods: Reported studies on the association between antenatal steroid and risk of ROP or severe ROP were identified from MEDLINE and Embase databases from their inception to November 2016. Outcome measures were ORs with 95% CIs. Extracted data were pooled using a random-effect model or fixed-effect model where appropriate. Heterogeneity was assessed, and sensitivity analysis was performed.

Results: A total of 434 relevant studies were identified, and 28 studies were eligible for the meta-analysis, involving 20 731 neonates with 4202 cases of ROP. Among the 28 studies included, 13 studies provided data evaluating the association between antenatal steroid use and severe ROP, involving 4999 neonates with 792 cases of severe ROP. Antenatal steroid administration was associated with a reduced risk of ROP development (OR=0.82, 95% CI 0.68 to 0.98; OR=0.67, 95% CI 0.47 to 0.94) and progression to severe ROP (OR=0.58, 95% CI 0.40 to 0.86).

Conclusion: Antenatal steroid administration is associated with a reduced risk of ROP development and progression to severe ROP. Our results strengthened the indications of antenatal steroid therapy to high-risk mothers giving preterm births, especially in low-income and middle-income countries where antenatal steroid are not yet widely used.
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http://dx.doi.org/10.1136/bjophthalmol-2017-311576DOI Listing
October 2018

Refractive Errors and Concomitant Strabismus: A Systematic Review and Meta-analysis.

Sci Rep 2016 10 12;6:35177. Epub 2016 Oct 12.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

This systematic review and meta-analysis is to evaluate the risk of development of concomitant strabismus due to refractive errors. Eligible studies published from 1946 to April 1, 2016 were identified from MEDLINE and EMBASE that evaluated any kinds of refractive errors (myopia, hyperopia, astigmatism and anisometropia) as an independent factor for concomitant exotropia and concomitant esotropia. Totally 5065 published records were retrieved for screening, 157 of them eligible for detailed evaluation. Finally 7 population-based studies involving 23,541 study subjects met our criteria for meta-analysis. The combined OR showed that myopia was a risk factor for exotropia (OR: 5.23, P = 0.0001). We found hyperopia had a dose-related effect for esotropia (OR for a spherical equivalent [SE] of 2-3 diopters [D]: 10.16, P = 0.01; OR for an SE of 3-4D: 17.83, P < 0.0001; OR for an SE of 4-5D: 41.01, P < 0.0001; OR for an SE of ≥5D: 162.68, P < 0.0001). Sensitivity analysis indicated our results were robust. Results of this study confirmed myopia as a risk for concomitant exotropia and identified a dose-related effect for hyperopia as a risk of concomitant esotropia.
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http://dx.doi.org/10.1038/srep35177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5059633PMC
October 2016

Association of Gestational Hypertensive Disorders with Retinopathy of prematurity: A Systematic Review and Meta-analysis.

Sci Rep 2016 08 5;6:30732. Epub 2016 Aug 5.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

The role of gestational hypertensive disorders, which includes both pre-eclampsia and gestational hypertension, in the development of retinopathy of prematurity (ROP) has been controversial. Therefore, this systematic review and meta-analysis is to evaluate the association between gestational hypertensive disoders and ROP. Eligible studies published up to June 5, 2016 were identified from MEDLINE and EMBASE that evaluated the association between the two conditions. Totally 1142 published records were retrieved for screening, 925 of them eligible for detailed evaluation. Finally 19 studies involving 45281 infants with 5388 cases of ROP met our criteria for meta-analysis. Gestational hypertensive disorders were not associated with ROP (unadjusted OR: 0.89; P = 0.38; adjusted OR: 1.35; P = 0.18). Subgroup analyses also revealed no significant association between ROP with pre-eclampsia (unadjusted OR: 0.85; P = 0.29; adjusted OR:1.29; P = 0.28) or with gestational hypertension (unadjusted OR: 1.10; P = 0.39; adjusted OR: 1.25; P = 0.60) separately. Sensitivity analysis indicated our results were robust. We concluded no significant association between gestational hypertensive disorders and ROP. More large scale well-conducted prospective cohorts on the topic are needed.
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http://dx.doi.org/10.1038/srep30732DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4974497PMC
August 2016

The Natural Course of Intermittent Exotropia over a 3-year Period and the Factors Predicting the Control Deterioration.

Sci Rep 2016 06 3;6:27113. Epub 2016 Jun 3.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

The natural course of intermittent exotropia and the factors affecting its control has been unclear. We aim to report the natural course of our cohort of 117 Chinese children with intermittent exotropia and to identify baseline parameters that may have predictive value in the control deterioration of the disease. The visual acuity, spherical equivalent, compliance to orthoptic exercise, angle of deviation fusional convergence parameters and Newcastle Control Score were recorded for all children at baseline and at 3 years apart. Patients were divided into two groups according to the change in control over the 3 years: group 1 included patients who had no deterioration or had improvement in disease control; and group 2 were those who had deteriorated control or had undergone surgery. There were 77 patients (66%) in group 1 and 40 (34%) patients in group 2. Comparing the baseline parameters of the two groups, group 1 had statistically significantly smaller angle of deviation, larger fusional reserve, larger fusional recovery, and higher fusional reserve ratio (p < 0.05). Other baseline parameters were similar between the two groups. The baseline fusional parameters may have predictive value in determining the control of intermittent exotropia.
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http://dx.doi.org/10.1038/srep27113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4891815PMC
June 2016

Predictive factors affecting the short term and long term exodrift in patients with intermittent exotropia after bilateral rectus muscle recession and its effect on surgical outcome.

Biomed Res Int 2014 2;2014:482093. Epub 2014 Jul 2.

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.

Purpose: To determine the predictive factors that affect short term and long term postoperative drift in intermittent exotropia after bilateral lateral rectus recession and to evaluate its effect on surgical outcome.

Methods: Retrospective review of 203 patients with diagnosis of intermittent exotropia, who had surgical corrections with more than 3 years of followup. Different preoperative parameters were obtained and evaluated using Pearson's correlation analysis.

Results: The proportion of exodrift increased from 62% at 6 weeks to 84% at 3 years postoperatively. The postoperative drift was 4.3 ± 8.1 PD at 6 weeks, 5.8 ± 8.4 PD at 6 months, 7.2 ± 8.3 PD at 1 year, 7.4 ± 8.4 PD at 2 years, and 7.7 ± 8.5 PD at 3 years. Preoperative deviation and initial overcorrection were significant factors affecting the postoperative drift at 3 years (r = 0.177, P = 0.011, r = -0.349, and P < 0.001, resp.).

Conclusions: Postoperative exodrift along three years occurs in a majority of patients after bilateral lateral rectus recession for intermittent exotropia. The long term surgical success is significantly affected by this postoperative exodrift. A larger preoperative deviation and a larger initial overcorrection are associated with a larger early and late postoperative exodrift.
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http://dx.doi.org/10.1155/2014/482093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4100361PMC
March 2015

A prospective study of fusional convergence parameters in Chinese patients with intermittent exotropia.

J AAPOS 2013 Aug 31;17(4):347-51. Epub 2013 Jul 31.

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.

Purpose: To evaluate the correlation between different fusional convergence parameters and the Newcastle Control Score (NCS) in children with intermittent exotropia.

Methods: In this consecutive prospective observational series, 101 Chinese children with intermittent exotropia were examined by a single observer, who assessed the level of control using the revised NCS and measured the angle of deviation and fusional convergence. Levels of control were defined according to the NCS as good (0-3), moderate (4-6), or poor (7-9). The correlation between the different fusional convergence parameters and the NCS was evaluated.

Results: The total convergence amplitude was similar among the different control groups (P = 0.288 and P = 0.628 at near and at distance, respectively). The convergence reserve was higher in the good control group compared with the moderate and poor control groups, both at near (P = 0.001) and at distance (P = 0.001). Among all fusional convergence parameters, we determined that the fusional reserve ratio had strongest correlation with control (near ratio: r = -0.66, P = 0.001; distant ratio: r = -0.59, P = 0.001). Among patients with a fusional reserve ratio ≥ 2 at distance, 100% (5 of 5 patients) of these patients demonstrated good control (NCS ≤ 3).

Conclusions: In children with intermittent exotropia, the total convergence amplitude was similar among different levels of control. The convergence reserve was lower in the poor control group. Fusional reserve ratio ≥ 2 was an indicator of good control in patients.
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http://dx.doi.org/10.1016/j.jaapos.2013.03.023DOI Listing
August 2013

Prognostic factors predicting the surgical outcome of bilateral lateral rectus recession surgery for patients with infantile exotropia.

Jpn J Ophthalmol 2013 Sep 17;57(5):481-5. Epub 2013 Jul 17.

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong, China,

Purpose: To determine the presurgery factors affecting early and long-term favorable outcomes of bilateral lateral rectus recession surgery for infantile exotropia.

Patients And Methods: A retrospective study of 50 patients with infantile exotropia (both constant-type and intermittent-type exotropia with onset before 1 year of age) who had bilateral lateral rectus recession surgery correction with more than 1 year follow up. Presurgery data were obtained and evaluated by use of multiple regression analysis.

Results: Smaller presurgery distance deviation (p = 0.042), older age at surgery (p = 0.025), longer interval between onset and surgery (p = 0.020), and more myopic refractive error (p = 0.007) were associated with successful outcome at 6 weeks, but none was correlated with successful outcome at 1 year. Among all data, presurgery distance deviation was the only significant determinant (multiple regression analysis, p = 0.021) for successful outcome at 6 weeks. Presurgery distance deviation (β = 0.952, p < 0.001) was correlated with the distant angle of deviation 6 weeks (β = 0.952, p < 0.001) and 1 year (β = 0.394, p = 0.006) postsurgery.

Conclusions: Smaller presurgery deviation was found to be associated with more favorable surgical outcome.
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http://dx.doi.org/10.1007/s10384-013-0262-8DOI Listing
September 2013

Preoperative factors predicting the surgical response of bilateral lateral rectus recession surgery in patients with infantile exotropia.

J Pediatr Ophthalmol Strabismus 2013 Jul-Aug;50(4):245-50. Epub 2013 May 14.

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.

Purpose: To determine the preoperative factors affecting the efficacy in bilateral lateral rectus recession surgery for infantile exotropia.

Methods: This was a retrospective study of 50 patients with infantile exotropia who had bilateral lateral rectus recession surgery correction with more than 1 year of follow-up. Preoperative parameters influencing the response of the surgery were obtained and evaluated using multiple regression analysis including age at onset, age at surgery, interval between onset and surgery, preoperative deviation, refractive error, anisometropia, amount of surgery performed, presence of A- or V-pattern, and preoperative phase of exotropia. The response to surgery was defined as the change in deviation divided by the amount of the surgery.

Results: Thirty-two (64%) and 24 (48%) patients had successful outcome at 6 weeks and 1 year postoperatively, respectively. The mean response to surgery was 1.79 ± 0.63 prism diopters (PD)/mm recession at 6 weeks and 1.58 ± 0.75 PD/mm recession at 1 year postoperatively. Exotropic drift was 5.12 ± 7.27 PD at 6 weeks and 8.02 ± 6.81 PD at 1 year postoperatively. Pre-operative deviation was correlated with the response of surgery at 6 weeks (β = 0.342, P = .020) and 1 year (β = 0.391, P = .007) postoperatively.

Conclusions: Surgical response decreases over time due to the exotropic drift. Larger preoperative distance deviation was associated with larger surgical response. Both the exotropic drift and the preoperative deviation should be considered in applying the surgical dose in infantile exotropia.
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http://dx.doi.org/10.3928/01913913-20130507-01DOI Listing
March 2014

Long-term ocular alignment after bilateral lateral rectus recession in children with infantile and intermittent exotropia.

J AAPOS 2012 Jun;16(3):274-9

Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.

Purpose: To compare postoperative drift after bilateral lateral rectus recession for infantile exotropia (XT) and for intermittent XT and to compare initial postoperative alignment with long-term motor outcome.

Methods: Medical records of all patients with infantile exotropia or intermittent exotropia who had undergone bilateral lateral rectus muscle recession surgery with a follow-up longer than 3 years were reviewed. The pre- and postoperative angles of deviation at distance and at near and postoperative drift at distance were compared. Surgical outcome was categorized as "success" (esotropia <6(Δ) or exotropia <11(Δ)), "recurrence" (>10(Δ) exotropia), or "overcorrection" (>5(Δ) of esotropia).

Results: The overall mean postoperative exotropic drift at 3 years was 10.4(Δ) in the infantile XT group and 7.2(Δ) in the intermittent XT group (P = 0.05). Both groups had a low success rate at 3 years: 41% in the infantile XT group and 51% in the intermittent XT group (P = 0.270). For patients with an initial esotropia of 0(Δ) to 10(Δ), the success rate at 3 years was 86% in the infantile XT group (12 of 14) and 65% in the intermittent XT group (28 of 43).

Conclusions: Postoperative exotropic drift is clinically similar in patients with intermittent versus infantile exotropia. Esotropia of 0(Δ) to 10(Δ) during the early postoperative period may be associated with the best long-term ocular alignment.
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http://dx.doi.org/10.1016/j.jaapos.2012.01.005DOI Listing
June 2012

Refractive changes after pediatric intraocular lens implantation in Hong Kong children.

J Pediatr Ophthalmol Strabismus 2012 Sep-Oct;49(5):308-13. Epub 2012 May 8.

Purpose: To report the refractive changes after cataract surgery and intraocular lens (IOL) implantation in Hong Kong Chinese children.

Methods: The clinical records of all patients who had cataract extraction and IOL implantation before age 18 years and with more than 2 years of follow-up were studied retrospectively. The refractive errors of all patients determined by cycloplegic refraction at 6 weeks, 3 months, 6 months, and 1 year postoperatively and then annually thereafter were included for analysis. Patients were stratified into groups according to their age at IOL implantation for analysis.

Results: Twenty-six eyes (81.3%) had developmental cataracts, 3 eyes (9.4%) had traumatic cataracts, and 3 eyes (9.4%) were iatrogenic (from surgical or medical treatment). Patients demonstrated a mean myopic shift (diopters) of -5.53 (0 to 2 years old) -4.68 (3 to 5 years old), -2.60 (6 to 8 years old), -0.42 (9 to 11 years), and -0.09 (> 11 years). There was no significant difference in myopic shift between eyes that were operated on and those that were not. No statistically significant differences in refractive change were found in comparing males to females, unilateral to bilateral cases, traumatic to non-traumatic cases, amblyopic to nonamblyopic eyes, primary to secondary intraocular lenses, or polymethylmethacrylate to acrylic IOLs.

Conclusion: The postoperative myopic shift in pediatric patients undergoing IOL implantation is greatest in the younger age groups and persists until at least 8 years of age. The mean rate of myopic shift also decreases with age. The refractive development of the pseudophakic eyes was not significantly different from the fellow phakic eyes.
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http://dx.doi.org/10.3928/01913913-20120501-04DOI Listing
July 2014

Exotropic drift and ocular alignment after surgical correction for intermittent exotropia.

J Pediatr Ophthalmol Strabismus 2010 Jan-Feb;47(1):12-6. Epub 2010 Jan 21.

Hong Kong Island Cluster Ophthalmology Service, Hoong Kong, The People's Republic of China.

Purpose: To evaluate changes in the angle of deviation over time and compare the motor success rate with different initial postoperative deviation in patients undergoing surgical correction for intermittent exotropia.

Methods: Forty-eight patients aged between 1 and 10 years who underwent bilateral lateral rectus recession for intermittent exotropia were retrospectively evaluated. Preoperative and postoperative ocular deviations at 1 week, 1 month, and 6 months were analyzed. Full surgical correction was attempted in all patients. Motor success was defined as ocular deviation within 10 prism diopters of orthophoria at 6 months postoperatively.

Results: The follow-up period ranged from 6 months to 3 years. Although most patients had exotropic drift, this drift was greater in patients with initial esotropia (86.7%) and orthophoria (70.0%) compared to patients with exotropia (26.1%). Motor success was achieved in 29 (60.4%) patients. There was no statistical difference between ocular alignment at 1 week postoperatively and final motor success (P = .782). There was good correlation between ocular alignment at 1 week and 6 months postoperatively (rho = 0.585, P < .001). Age and preoperative deviation were not found to be associated with motor success.

Conclusions: The success rate appears to be unaffected by initial ocular alignment, suggesting that deliberate initial overcorrection may be unnecessary. Future studies are warranted to evaluate the long-term stability of this alignment.
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http://dx.doi.org/10.3928/01913913-20100106-04DOI Listing
March 2010