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Year : 2016  |  Volume : 64  |  Issue : 7  |  Page : 496-499

Nasolacrimal duct obstruction: Does it really increase the risk of amblyopia in children?

1 Department of Pediatric Ophthalmology and Strabismus, Sankara Nethralaya, Chennai, Tamil Nadu, India
2 Department of Orbit, Oculoplasty, Reconstructive and Aesthetic Services, Sankara Nethralaya, Chennai, Tamil Nadu, India

Date of Submission15-Jun-2015
Date of Acceptance01-May-2016
Date of Web Publication9-Sep-2016

Correspondence Address:
Sumita Agarkar
Sankara Nethralaya, Medical Research Foundation, 18, College Road, Chennai 600 006, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0301-4738.190101

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Purpose: To report the prevalence of amblyopia risk factors in children with congenital nasolacrimal duct obstruction. Methods: A retrospective review of records of children with the diagnosis of congenital nasolacrimal duct obstruction (NLDO), who underwent probing from January 2009 to October 2011, was done. All of them underwent a complete ophthalmic evaluation including cycloplegic refraction and strabismus evaluation before probing. Results: A total of 142 children were included in this study. The mean age at presentation was 22.38 months (sample standard deviation (SSD) - 15.88). Amblyopia risk factors were defined according to two sets of guidelines: The American Association for Pediatric Ophthalmology and Strabismus (AAPOS) referral criteria guidelines and the new AAPOS Vision Screening Committee guidelines. Twenty-eight (20%) children were found to have some form of amblyopia risk factor based on the referral criteria prescribed by AAPOS. However, on applying modified guidelines described by Donahue et al., to analyze the same cohort, 21 children were found to have amblyogenic risk factors. Of these 28 children, 13 had significant astigmatism (>1.50 D), 8 children had hypermetropia (>3.50 D), and six children had anisometropia (>1.50 D). One child had significant cataract (media opacity >1 mm). None of the children in this series had either myopia or strabismus. Conclusion: Prevalence of amblyopia risk factor was found to be 20% in our study based on the older guidelines; however, it reduces to 14.78% by applying the modified guidelines. Despite this reduction, importance of a comprehensive ophthalmic examination including cycloplegic refraction in all children presenting with NLDO cannot be overstated. A close follow-up of these children is also essential to prevent the development of amblyopia.

Keywords: Amblyopia risk factors, anisometropia, congenital nasolacrimal duct obstruction

How to cite this article:
Ramkumar V A, Agarkar S, Mukherjee B. Nasolacrimal duct obstruction: Does it really increase the risk of amblyopia in children?. Indian J Ophthalmol 2016;64:496-9

How to cite this URL:
Ramkumar V A, Agarkar S, Mukherjee B. Nasolacrimal duct obstruction: Does it really increase the risk of amblyopia in children?. Indian J Ophthalmol [serial online] 2016 [cited 2020 Jul 8];64:496-9. Available from: http://www.ijo.in/text.asp?2016/64/7/496/190101

Congenital nasolacrimal duct obstruction (CNLDO) affects up to 20% of infants and is one of the most common problems encountered in a pediatric ophthalmology practice. [1] Presenting features of CNLDO include constant epiphora and intermittent discharge involving one or both the eyes. It is usually considered a benign disease as far as visual development is concerned. Most of these children (90%) undergo spontaneous resolution in the 1 st year of life, whereas the remaining children continue to have symptoms beyond 1 year of age. [2],[3],[4] Normal development of visual system in early life requires the presence of a sharply focused retinal image. It is not known if persistent tearing has any role in the visual development of children. Although there are reports of anisometropic amblyopia associated with CNLDO, studies have remained largely inconclusive. [5],[6] Hypothetically, persistent watering in CNLDO can lead to blurring of vision and form-deprivation amblyopia during the sensitive period of visual development. Hence, disorders of binocular function are likely to be more common in this group of children. [7],[8] The objective of this study was to describe the prevalence of factors which can potentially lead to amblyopia in children with CNLDO.

  Methods Top

This is a retrospective case series. The medical records of all children below 5 years, diagnosed with CNLDO and who underwent probing from January 2009 to October 2011, were retrospectively reviewed. The diagnosis of CNLDO was made clinically, based on the presence of an increased tear film height with matted lashes and regurgitation on pressure over the lacrimal sac. Probing, according to our institutional protocol, was performed only if the child was at least 1 year of age or older. Younger children were initially managed by conservative approach of Criggler's massage till they were at least 1 year old. Early probing was done in situations where intraocular surgery was planned, or there was recurrent episode of acute dacryocystitis.

A total of 142 children were included in the study. Data on the patients' gestational age, birth weight, age at diagnosis, and associated systemic diseases were noted. Children with low birth weight (1500-2500 g), history of prematurity, and those who had a family history of amblyopia were excluded from this study, as these are independent risk factors for the development of amblyopia. A comprehensive ophthalmic examination was done in all these children, which included visual acuity, cycloplegic refraction, cover test, and a detailed anterior segment and fundus evaluation. Children <2 years were dilated with homatropine and tropicamide and children more than 2 years were dilated with cyclopentolate, and tropicamide after ruling out systemic contraindications.

Amblyopia risk factors were identified in accordance with the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) referral criteria guidelines [9] which include: anisometropia - spherical/cylindrical >1.5 D, any manifest strabismus,hyperopia >3.5D in any meridian, myopia magnitude >3.0D in any meridian, any media opacity>1 mm in size, astigmatism >1.5 D at 90 or 180 or more than 1D in oblique axis, ptosis 1mm marginal reflex distance

The revised guidelines for amblyopia risk factors (ARFs) in preschool children, proposed by Donahue et al. [10] were more age specific. According to the newer guidelines, magnitude of refractive error associated with increased risk of amblyopia was as follows: In children aged 12-30 months, astigmatism of 2.0 D, hyperopia of 4.5 D, myopia of 3.5 D, and anisometropia of 2.5; in children aged 31-48 months, astigmatism of 2.0 D, hyperopia of 4.0 D, anisometropia of 2.0 D, and myopia of 3.0 D; and children older than 48 months, astigmatism of 1.50 D, hyperopia of 3.50 D, anisometropia of 1.5 D, and myopia of 1.5 D. The nonrefractive risk factors included any media opacity more than 1 mm and any form of manifest strabismus of more than 8 PD.

  Results Top

Of the 142 children included in the study, 94 were males and rest 48 were females. The mean age at presentation was 22.38 months (SSD - 15.88 months). CNLDO was present in the right eye in 65 children (45.77%), left eye in 57 children (40.14%), and was bilateral in 20 (14.08%). Amblyopia risk factors were identified in 28 children (20%) based on the older criteria. Among these 28 children, CNLDO was distributed equally on the right and left side in 10 patients each and was bilateral in 8 patients. The mean age of children with CNLDO who had amblyopiagenic risk factors (ARF) was 3.25 years. The most common refractive error, as far as potential risk of amblyopia is concerned, was astigmatism seen in 13 subjects, followed by hypermetropia in 8 and anisometropia was seen in 6 patients. However, when we reanalyzed our dataset using the revised guidelines proposed by Donahue et al. published in 2013, only 21 (14.78%) children had some form of ARF [Table 1]. One of the aim of our study was to compare the Amblyogenic factors applying both the criteria, the reason why both the criteria have been used. One child had a visually significant cataract. None of the children in our cohort had significant myopia, strabismus, or ptosis. There was no correlation between the laterality of CNLDO and the degree of refractive error in children with either hypermetropia or astigmatism. Interestingly, in all children with unilateral CNLDO and anisometropia, the eye with NLDO was more ametropic compared to the fellow eye [Table 2]. Mean follow-up was 9.54 months. Of the 28 children identified with risk factors, 2 developed amblyopia requiring occlusion and 3 children were lost to follow-up despite significant anisometropia. Seven children were prescribed glasses. The remaining children were kept under regular monitoring. The child with cataract underwent cataract extraction and is under regular follow-up.
Table 1: Comparison of ARF applying the older and the newer guidelines refractive ARF

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Table 2: Laterality of congenital nasolacrimal duct obstruction in children with anisometropia

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  Discussion Top

CNLDO has been speculated to have an increased risk of amblyopia for various reasons in the past. In the recent years, there have been series of articles supporting this hypothesis. Most of these studies have applied the older guidelines used to define amblyogenic risk factors. However, does CNLDO really increase the risk of amblyopia or is it dependent on the criteria applied to define these risk factors? This prompted us to compare the prevalence of the risk factors applying both sets of guidelines available in the literature, in children with CNLDO.

is defined as reduced visual acuity in one or both the eyes resulting from reduced visual input or abnormal binocular interaction early in life, in the absence of any organic cause. It is one of the most common causes of unilateral visual impairment in children, with a prevalence of 2-5%. [11] Apart from refractive error, strabismus, and sensory deprivation, there are other independent risk factors associated with amblyopia. These include heredity, low birth weight (1500-2500 g), mental disability, craniosynostosis, hydrocephalus, and blepharophimosis, to mention a few. [12],[13],[14],[15],[16],[17]

There has been a limited investigation into the association of CNLDO with other visual disorders. Studies in primates have shown two sensitive periods in the development of neurological substrate for binocular vision. The first stage extends from birth to 8 weeks and the second stage extends from 8 weeks to 12-18 months. [7] Clear focusing of the images on the retina is very vital for emmetropization. Persistent unilateral watering and discharge leading to a blurring of vision during this period of competitive interaction may be sufficient enough to disrupt emmetropization and result in an increased incidence of strabismus, anisometropia, and amblyopia.

Ellis et al. have looked into the hypothesis that tear film disturbance in CNLDO may interfere with visual maturation. [8] They compared the overall incidence of ametropia, anisometropia, or astigmatism in CNLDO with the control group. They found no evidence to prove that disruption by tear film in CNLDO interfered with emmetropization or developing ocular alignment.

Chalmers and Griffith in their retrospective study of 210 patients with CNLDO found that 3.9% of children with unilateral NLDO developed amblyopia in the affected eye. [6] About 4.65% of these children subsequently went on to develop strabismus. In children with bilateral NLDO, 1.25% went on to develop amblyopia.

In 2003, the Vision Screening Committee of the AAPOS revised the guidelines which primarily defined the quantum of refractive error which was sufficient to put the child at risk for the development of amblyopia - or in other words the "Amblyopia Risk factors". These guidelines are based on stronger evidence and consensus. The guidelines proposed by Donahue et al. identified those children who are more at risk for developing amblyopia compared to those who had low risk.

Based on the older guidelines, the prevalence of ARF in the normal population is reported to be around 15-20%; [18],[19],[20] however, a majority of these children do not develop amblyopia. Matta and Silbert observed an increased prevalence of amblyopia risk factor in children with CNLDO. [21] They found that 22% of children under 3 years of age with CNLDO had amblyopiagenic risk factor as defined by the older guidelines. Sixty-three percent of these children developed amblyopia requiring treatment. This observation has echoed in other studies all over the globe including our study. Matta et al. found an increased incidence of significant astigmatism. [22] In their study, 45 of the 71 children with significant refractive error, had astigmatism. Similarly, in our study, astigmatism was the most common refractive error.

Simon et al. in a study on anisometropic amblyopia and NLDO, has described five children with NLDO and anisometropic amblyopia involving the affected eye. [23] In our study, six children had unilateral CNLDO and anisometropia. All of them had greater hypermetropia on the affected side compared to the fellow eye. Two of these children in this group went on to develop amblyopia requiring glasses and occlusion.

Published data on the prevalence of anisometropia (≥1 D difference between the eyes) in the pediatric population show prevalence ranging from 2.3% to 3.4% (age 5-11 years). [24],[25] The prevalence of anisometropia (≥1.50 D) in our study population (0-5 years) was 4.23%.

The possible explanation for the increased prevalence of the relative hypermetropia on the side of CNLDO could be interference with emmetropization. Considering the group of children with the amblyogenic potential was relatively older (mean age - 3.25 years) as compared to the study cohort (mean age - 1.5 years), it is difficult to explain the relative hypermetropia. The alternative probable hypothesis would be an anatomical abnormality of the orbit resulting in failure of canalization either unilateral or bilateral along with a reduced axial length of the globe leading to hypermetropia. [26] Further studies are needed to establish the exact cause and association of relative hypermetropia.

Our data showed the presence of amblyopiagenic risk factors in 20% of our patients; however, when we reanalyzed the data set applying the modified guidelines, there was a significant reduction in the prevalence to 14.78% which is closer to what has been reported in the general population. [18],[19],[20] Hence, CNLDO perhaps is not an additional factor increasing the risk of amblyopia as thought earlier. Despite a reduction in the prevalence of factors by reanalyzing the data, there is no denying the fact that children with CNLDO require a comprehensive ophthalmic evaluation and these risk factors would otherwise be missed.

The major limitation of our study was the absence of a control group of age-matched normal children to compare the prevalence of the risk factors. The other limitation of our study was the selection bias, as we included only children who underwent probing. It is possible that we may have missed including some children with amblyopia risk factors in this study who had a resolution of NLDO either spontaneously or with conservative therapy.

  Conclusion Top

Prevalence of amblyogenic risk factors was found to be 20% in this study. Prevalence reduces from 20% to 14.78% on applying modified guidelines, which is comparable to the prevalence reported in the general population. CNLDO does not appear to be an additional independent risk factor for developing amblyopia. Irrespective of the prevalence rate, these children who present with symptoms of CNLDO need a comprehensive ophthalmic evaluation including a cycloplegic refraction and subsequent follow-up to prevent amblyopia.

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Conflicts of interest

There are no conflicts of interest.

  References Top

MacEwen CJ, Young JD. Epiphora during the first year of life. Eye (Lond) 1991;5(Pt 5):596-600.  Back to cited text no. 1
Atkinson J, Braddick O, Nardini M, Anker S. Infant hyperopia: Detection, distribution, changes and correlates-outcomes from the cambridge infant screening programs. Optom Vis Sci 2007;84:84-96.  Back to cited text no. 2
Kendig EL Jr., Guerry D 3 rd . The incidence of congenital impotency of the nasolacrimal duct. J Pediatr 1950;36:212.  Back to cited text no. 3
Paul TO, Shepherd R. Congenital nasolacrimal duct obstruction: Natural history and the timing of optimal intervention. J Pediatr Ophthalmol Strabismus 1994;31:362-7.  Back to cited text no. 4
Young JD, MacEwen CJ, Ogston SA. Congenital nasolacrimal duct obstruction in the second year of life: A multicentre trial of management. Eye (Lond) 1996;10(Pt 4):485-91.  Back to cited text no. 5
Chalmers R, Griffiths PG. Is congenital nasolacrimal duct obstruction a risk factor for the development of amblyopia? Br Orthopt J 1996;53:29-30.  Back to cited text no. 6
Sloper JJ. Edridge-green lecture. Competition and cooperation in visual development. Eye (Lond) 1993;7(Pt 3):319-31.  Back to cited text no. 7
Ellis JD, MacEwen CJ, Young JD. Can congenital nasolacrimal-duct obstruction interfere with visual development? A cohort case control study. J Pediatr Ophthalmol Strabismus 1998;35:81-5.  Back to cited text no. 8
Donahue SP, Arnold RW, Ruben JB; AAPOS Vision Screening Committee. Preschool vision screening: What should we be detecting and how should we report it? Uniform guidelines for reporting results of preschool vision screening studies. J AAPOS 2003;7:314-6.  Back to cited text no. 9
Donahue SP, Arthur B, Neely DE, Arnold RW, Silbert D, Ruben JB; POS Vision Screening Committee. Guidelines for automated preschool vision screening: A 10-year, evidence-based update. J AAPOS 2013;17:4-8.  Back to cited text no. 10
Simons K. Amblyopia characterization, treatment, and prophylaxis. Surv Ophthalmol 2005;50:123-66.  Back to cited text no. 11
Mvogo CE, Ellong A, Bella-Hiag AL, Luma-Namme H. Hereditary factors in strabismus. Sante 2001;11:237-9.  Back to cited text no. 12
Robaei D, Kifley A, Gole GA, Mitchell P. The impact of modest prematurity on visual function at age 6 years: Findings from a population-based study. Arch Ophthalmol 2006;124:871-7.  Back to cited text no. 13
Bothe N, Lieb B, Schäfer WD. Development of impaired vision in mentally handicapped children. Klin Monbl Augenheilkd 1991;198:509-14.  Back to cited text no. 14
Tay T, Martin F, Rowe N, Johnson K, Poole M, Tan K, et al. Prevalence and causes of visual impairment in craniosynostotic syndromes. Clin Experiment Ophthalmol 2006;34:434-40.  Back to cited text no. 15
Altintas O, Etus V, Etus H, Ceylan S, Caglar Y. Risk of strabismus and ambylopia in children with hydrocephalus. Graefes Arch Clin Exp Ophthalmol 2005;243:1213-7.  Back to cited text no. 16
Beaconsfield M, Walker JW, Collin JR. Visual development in the blepharophimosis syndrome. Br J Ophthalmol 1991;75:746-8.  Back to cited text no. 17
Borchert M, Tarczy-Hornoch K, Cotter SA, Liu N, Azen SP, Varma R; MEPEDS Group. Anisometropia in hispanic and African American infants and young children the multi-ethnic pediatric eye disease study. Ophthalmology 2010;117:148-53.  Back to cited text no. 18
Multi-Ethnic Pediatric Eye Disease Study Group. Prevalence of myopia and hyperopia in 6-to 72-month-old African American and Hispanic children: The multi-ethnic pediatric eye disease study. Ophthalmology 2010;117:140-7.  Back to cited text no. 19
Fozailoff A, Tarczy-Hornoch K, Cotter S, Wen G, Lin J, Borchert M, et al. Prevalence of astigmatism in 6-to 72-month-old African American and Hispanic children: The Multi-ethnic Pediatric Eye Disease Study. Ophthalmology 2011;118:284-93.  Back to cited text no. 20
Matta NS, Silbert DI. High prevalence of amblyopia risk factors in preverbal children with nasolacrimal duct obstruction. J AAPOS 2011;15:350-2.  Back to cited text no. 21
Matta NS, Singman EL, Silbert DI. Prevalence of amblyopia risk factors in congenital nasolacrimal duct obstruction. J AAPOS 2010;14:386-8.  Back to cited text no. 22
Simon JW, Ngo Y, Ahn E, Khachikian S. Anisometropic amblyopia and nasolacrimal duct obstruction. J Pediatr Ophthalmol Strabismus 2009;46:182-3.  Back to cited text no. 23
Flom MC, Neumaier RW. Prevalence of amblyopia. Public Health Rep 1966;81:329-41.  Back to cited text no. 24
Peters HB, Blum HL, Betman JW, Johnson F, Fellows V Jr. The Orinda vision study. Am J Optom Arch Am Acad Optom 1959;36:455-69.  Back to cited text no. 25
Shih YF, Hsiao CH, Wen SH, Lin LL, Chen CJ, Hung PT. Prevalence of anisometropia in Taiwanese schoolchildren. J Formos Med Assoc 2005;104:412-7.  Back to cited text no. 26


  [Table 1], [Table 2]


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