A Hospital-Based Study on Amblyopia Prevalence in Children Under 10 with Congenital Ptosis

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Journal of MedVerse Research & Practice

nurexus.com

A Hospital-Based Study on Amblyopia Prevalence in Children Under 10

with Congenital Ptosis

Dr. Shanmathy

, Dr. Indhuja

Department of Ophthalmology, SRM Medical College Hospital, Trichy.

Email ID: drshanmathy@gmail.com

Submission Date: 20.05.2023

Accepted Date: 16.06.2023

Published Date: 30.06.2023

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Background: Congenital ptosis is a birth defect characterized by a drooping upper eyelid, evident at birth or soon

after. This condition is associated with abnormalities in the elevator muscle and neural dysfunction. The

occurrence rate of congenital ptosis falls between 0.18% and 1.41%. It may be linked to various eye-related issues

such as refractive errors, strabismus, or obstruction of the visual axis, potentially resulting in amblyopia.

Methods: Researchers conducted a forward-looking, cross-sectional investigation involving 50 pediatric patients

under 10 who were diagnosed with congenital ptosis. The study took place at a tertiary healthcare facility between

January and December 2022. The research team gathered and encoded the data, subsequently analyzing it using

SPSS version 27. They employed both descriptive and inferential statistical methods, considering p-values below

0.05 as statistically significant.

Results: The study included 50 participants with an average age of 6.95 ± 2.12 years, evenly split between males

and females. Unilateral ptosis was observed in 36 (72%) individuals, while 14 (28%) exhibited bilateral ptosis.

Amblyopia affected 45% of the cases. Refractive error was the leading cause of amblyopia (60%), followed by

deprivation (18%), strabismus (14%), and a combination of factors (9%). A statistically significant correlation

was found between congenital ptosis and amblyopia (p < 0.001).

Conclusion: Thoroughly assessing children with congenital ptosis is vital for detecting factors that may lead to

amblyopia. Timely action, including correcting refractive errors and performing surgical procedures, plays a

crucial role in successfully rehabilitating vision.

Keywords: Hospital-Based Study, Amblyopia, Prevalence, Congenital Ptosis

Introduction

Upper eyelid drooping, known as congenital ptosis, is a condition that manifests at birth or during early

childhood. This disorder primarily stems from myogenic or neurogenic issues, such as inadequate

levator muscle performance, congenital third nerve paralysis, or Horner syndrome. Worldwide, the

occurrence of congenital ptosis is believed to fall between 0.18% and 1.41% [1,2]. This ailment is linked

to an elevated likelihood of visual problems, particularly amblyopia, which can hinder normal visual

growth and development.

"Lazy eye," or amblyopia, occurs when the brain suppresses visual input from one eye to prevent double

vision. Children with congenital ptosis may develop amblyopia due to refractive errors, visual axis

obstruction from a drooping eyelid, or strabismus. Studies show that amblyopia affects 14–48% of

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congenital ptosis cases [3,4]. This condition substantially affects quality of life, visual acuity, and

binocular vision, highlighting the importance of early detection and treatment [5,6].

The objective of this research was to explore the occurrence of amblyopia among children affected by

congenital ptosis and to analyse the elements that contribute to its onset. Through identifying these

relationships, the study aimed to underscore the necessity for early detection, treatment, and

rehabilitation efforts.

Materials and Methods

Study Design and Setting

This hospital-based prospective cross-sectional study was conducted in the Ophthalmology Department

of a tertiary care center from January to December 2023. Ethical approval was obtained from our

institutional review board.

Participants

The study included 50 children under 10 years old who were diagnosed with congenital ptosis. Patients

with acquired ptosis, previous eye surgery, or systemic conditions affecting vision were excluded from

the study.

Procedures

• Every subject underwent a thorough eye examination, which consisted of the following

components:

• Vision Testing: A Snellen chart was utilized to determine the best-corrected visual acuity

(BCVA). Amblyopia was identified when there was a difference of two or more lines in BCVA

between eyes, or if the affected eye had a BCVA below 6/60.

• Droopy Eyelid Assessment: Measurements were taken for margin reflex distance 1 (MRD1),

levator muscle function, and the height of the upper eyelid crease. The condition's severity was

classified as mild (MRD1 between 2-3 mm), moderate (MRD1 between 1-2 mm), or severe

(MRD1 of 0 mm or less).

• Refractive Error Evaluation: Cycloplegic refraction was conducted using 1% cyclopentolate.

Refractive errors considered amblyogenic included anisometropia (1 dioptre or more),

astigmatism (1 dioptre or more), hypermetropia (4 dioptres or more), and myopia (6 dioptres or

more).

• Eye Alignment Check: The cover test was employed to assess ocular alignment.

Data Collection and Analysis: Microsoft Excel was utilized for data entry, while SPSS version 27 was

employed for analysis. The results are presented as frequencies and percentages in descriptive statistics.

To evaluate associations, the chi-square test was applied, with a significance threshold established at p <

0.05.

Results

Demographics

The research involved 50 children with an average age of 6.95 years (SD = 2.12) and an age range from

2 to 10 years. There was an equal split between genders, with 25 boys and 25 girls, each representing

50% of the sample. Over half of the participants (62%) were at least 5 years old.

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Table 1: Age Distribution

Age Group

Frequency

Percentage

< 5 years

40%

≥ 5 years

60%

Chart 1: Gender Distribution

The study population consisted of an equal number of men and women, with 25 (50%) participants from

each gender.

Table 2: Types of Congenital Ptosis

Type

Frequency

Percentage

Simple Ptosis

40%

Blepharophimosis

22%

Fibrosis Syndrome

18%

Third Nerve Palsy

14%

Mono-Elevation Deficit

Single-sided ptosis affected 36 patients (72%), while 14 patients (28%) experienced the condition in

both eyes.

Table 3: Causes of Amblyopia

Cause

Frequency

Percentage

Refractive

60%

Deprivation

18%

Strabismus

14%

Mixed

Refractive Amblyopia (60%): The most prevalent cause arises from significant differences in refractive

power between the eyes, such as astigmatism, hypermetropia, or myopia.

Deprivation Amblyopia (18%): Caused by obstruction of the visual axis due to ptosis, leading to

reduced visual stimulation.

Strabismic Amblyopia (14%): results from misaligned eyes in which the brain suppresses input from

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one eye to avoid double vision.

Mixed Amblyopia (8%): A combination of refractive errors, deprivation, and strabismus.

Table 4: Association Between Ptosis Severity and Amblyopia

Severity

Amblyopia Present

Amblyopia Absent

Total

Mild

Moderate

Severe

Among participants with amblyopia, the severity of ptosis played a significant role. Severe ptosis cases

demonstrated a higher prevalence of amblyopia than mild or moderate ptosis cases.

Statistical Significance: The association between congenital ptosis and amblyopia was statistically

significant (P < 0.001). Refractive errors were the leading amblyogenic factor, followed by deprivation

caused by severe ptosis.

Chart 2: Amblyopia Prevalence by Cause

The distribution of causes among the study participants showed that refractive errors accounted for the

majority at 60%, followed by deprivation in 18% of cases and strabismus in 14%. Mixed factors

contributed to 9% of the cases. This indicates that refractive errors were the leading cause, highlighting

the importance of early detection and correction of visual defects to prevent further complications.

Visual Outcomes

A portion of study participants experienced enhanced visual acuity following interventions involving

refractive correction and surgical procedures. These results highlight the critical nature of early

detection and intervention in eye care.

Discussion

This study found that 40% of children with congenital ptosis had amblyopia, which is consistent with

earlier reports documenting prevalence rates ranging from 14% to 48% (Griepentrog et al. [3],

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Schneider et al. [7]). Refractive error emerged as the predominant contributing factor, accounting for

60% of amblyopia cases. This finding is in agreement with studies by Oral et al. [4], who reported

refractive amblyopia in 71% of cases, and Paik et al. [5], who observed similar refractive patterns. These

findings highlight the importance of early detection and timely correction of refractive errors to reduce

the risk of amblyopia in children with congenital ptosis.

In the present study, 18% of children were found to have deprivation amblyopia. Obstruction of the

visual axis by the drooping eyelid is a recognized mechanism, although the risk may be partially

mitigated by compensatory behaviors such as chin elevation and head tilt. Similar observations have

been reported by Griepentrog et al. [3] and Hornblass et al. [11], who emphasized the protective role of

these compensatory postures in reducing visual deprivation.

Strabismus was identified as the underlying cause of amblyopia in 14% of cases. Strabismus interferes

with normal binocular vision development, leading to suppression of the deviating eye and subsequent

amblyopia. The association between congenital ptosis, strabismus, and amblyopia has been previously

explored by Schneider et al. [7] and Srinagesh et al. [6], supporting the findings of the present study.

The relationship between the severity of ptosis and the development of amblyopia remains controversial.

While studies by Merriam et al. [8] and Hornblass et al. [11] reported a direct association between

increased ptosis severity and higher amblyopia risk, other investigations by Stein et al. [13] and Beneish

et al. [9,15] found no significant correlation. In the present study, children with severe ptosis

demonstrated a higher incidence of amblyopia, lending support to studies that suggest ptosis severity

plays a contributory role.

Additionally, 10% of cases demonstrated a mixed etiology of amblyopia involving refractive errors,

strabismus, and visual deprivation. These complex presentations necessitate comprehensive ophthalmic

evaluation and individualized management strategies. Previous studies by Lin et al. [12,17] and Ugurbaş

et al. [10,18] have emphasized the importance of timely surgical correction of ptosis and its favorable

impact on amblyopia treatment outcomes.

Conclusion

This research emphasizes the widespread occurrence of amblyopia in children with congenital ptosis,

emphasizing how refractive error, deprivation, and strabismus contribute significantly to its onset.

Timely detection and treatment are crucial to prevent permanent visual deficits. Thorough eye

examinations, including measurements of ptosis, assessments of refractive errors, and correction of

strabismus, are vital for properly managing these cases. Post-operative visual rehabilitation is critical in

maximizing visual outcomes and enhancing quality of life. Managing congenital ptosis necessitates a

collaborative approach involving eye specialists, pediatrician, and vision rehabilitation experts.

Subsequent studies should examine long-term visual results and the effects of early surgical intervention

in larger patient groups.

Conflict of interest: Nil

References

1. Patel K, Carballo S, Thompson L. Ptosis. Dis Mon. 2017;63(3):74-9.

2. SooHoo JR, Davies BW, Allard FD and Durairaj VD. Congenital ptosis. Surv Ophthalmol.

2014;59(5):483-92.

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3. Griepentrog GJ, Diehl NN, Mohney BG. Amblyopia in Childhood Eyelid Ptosis. Am J Ophthalmol.

2013;155(6):1125-8.e1.

4. Oral Y, Ozgur OR, Akcay L et al. Congenital Ptosis and Amblyopia. J Pediatr Ophthalmol Strabismus.

2010;47(2):101-4.

5. Paik JS, Kim SA, Park SH, Yang SW. Refractive Error Characteristics in Congenital Ptosis. BMC

Ophthalmol. 2016;16:177.

6. Srinagesh V, Simon JW, Meyer DR, et al. Refractive Error and Congenital Ptosis. J AAPOS.

2011;15(6):541-4.

7. Schneider GG, Martus P. Stimulus Deprivation Amblyopia in Congenital Ptosis. Strabismus.

2000;8(4):261-70.

8. Merriam WW, Ellis FD, Helveston EM. Ptosis and Amblyopia. Am J Ophthalmol. 1980;89(3):401-7.

9. Beneish R, Williams F, Polomeno RC, et al. Unilateral Ptosis and Amblyopia. Can J Ophthalmol.

1983;18(3):127-30.

10. Ugurbas SH, Zilelioglu G. Corneal Topography in Ptosis. Eye (Lond). 1999;13(4):550-4.

11. Hornblass A, Adhikary HP. The Incidence of Amblyopia in Congenital Ptosis. Arch Ophthalmol.

1976;94(4):582-4.

12. Lin LK, Uzcategui N, Chang EL. Effect of Surgical Correction of Congenital Ptosis on Amblyopia.

Ophthalmic Plast Reconstr Surg. 2008;24(6):434-6.

13. Stein JD, Kim DS, Mundy KM. The Prevalence of Amblyopia in Children with Ptosis. J Pediatr

Ophthalmol Strabismus. 2011;48(5):269-74.

14. Merriam WW, Ellis FD. Congenital Ptosis: An Overview. Am J Ophthalmol. 1975;79(3):402-10.

15. Beneish R, Williams F. Correlation of Ptosis Severity and Amblyopia Development. Can J Ophthalmol.

1982;17(4):254-8.

16. Uğurbaş SH, Zilelioglu G. Compensatory Mechanisms in Congenital Ptosis. Eye (Lond). 1999;13(Pt

4):550-4.

17. Lin LK, Chang EL. The Impact of Ptosis Surgery on Binocular Vision. Ophthalmic Plast Reconstr Surg.

2008;24(6):434-6.

18. Ugurbaş SH, Zilelioglu G. Refractive Changes Post Ptosis Surgery. Eye (Lond). 1999;13(4):550-4.