NON-TRAUMATIC ECTOPIA LENTIS IN A PAEDIATRIC OPHTHALMOLOGY PRACTICE, IBADAN, NIGERIA

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M.O Ugalahi¹, E.O Onebunne², B.A. Olusanya¹, A.M Baiyeroju¹

1. Department of Ophthalmology, University College Hospital/College of Medicine, University of Ibadan.
2. Department of Ophthalmology, University College Hospital Ibadan, Nigeria.

Abstract

Background: Non-traumatic ectopia lentis is a rare ocular disorder usually associated with syndromes like Marfans’s syndrome, Weil-Marchesani and Homocystinuria. Ectopia lentis can lead to profound visual loss from refractive errors, glaucoma as well as retinal detachment if left unattended.

Aim: The aim of this study was to describe the clinical profile of patients with non-traumatic ectopia lentis in a paediatric ophthalmology clinic in Ibadan, Nigeria. Methods: The clinical records of children <16 years diagnosed with non- traumatic ectopia lentis at the Paediatric Ophthalmology Clinic, University College Hospital Ibadan, from May 1, 2015 to Dec 31, 2019 were retrospectively reviewed. Information on demography, family history, visual acuity (VA), mean refractive error (spherical equivalent), and management was retrieved.

Results: Clinical records of 25 patients were reviewed. The mean age was 8.9 (±3.41) years with a range of 2-15 years. Sixteen (64%) patients were males. All the patients had bilateral involvement. A positive family history of ectopia lentis was elicited in 6 (24%) patients. Thirteen (52%) patients had a Marfanoid habitus and superior displacement of the lens was observed in 26 (52%) eyes. The presenting visual acuity was <6/60 in 22 (44%) eyes. The spherical equivalent of the refractive errors ranged from -20.00DS to +13.25DS. Twenty (40%) eyes underwent surgery within the period of the study and the best corrected postoperative visual acuity improved by 2 or more lines in 12 (60%) of operated eyes.

Conclusion: Severe visual morbidity was common in this cohort of patients with ectopia lentis in our practice. Treatment provided some improvement in vision which highlights the need to encourage early presentation for care. Detailed family history is important as a few of the patients were diagnosed following acceptance of our invitation to siblings for ophthalmic evaluation.

Keywords: Ectopia lentis, Lensectomy, Aphakia, Childhood, Africa

Introduction

Ectopia Lentis is a hereditary or acquired displacement of the lens from its normal position.¹ In 1856, Karl Stellwag, an Austrian Ophthalmologist first introduced the term ‘Ectopia Lentis’ to describe an abnormal positioning of the crystalline lens relative to its natural position in the eye. Since then, it has been recognized as a hallmark of many systemic diseases; some of which have life threatening manifestations.² Hereditary ectopia lentis is frequently bilateral but rare case reports of familial unilateral ectopia lentis have been described.³ Congenital ectopia lentis is a rare ocular disorder. Point prevalence is reported as 0.83/10,000 live births in the Danish population.⁴ The prevalence in the Nigerian population is not known. However, a few cases have been reported in the country. ^5–11 In Benin, a retrospective case series described the ocular features of both adults and children with Marfan’s syndrome in a hospital-based setting. The commoner ocular features in the cohort were ectopia lentis in 92.3%, cataract in 69.2%, glaucoma and myopia in 30.8% each.⁷ Severe visual impairment and blindness was found to occur from delayed presentation and use of traditional eye medication. In Lagos, a case report highlighted the importance of a family assessment in individuals suspected of having Marfan’s syndrome. The report also underscored the need for detailed patient assessment in this syndrome that is associated with multiorgan involvement.6 A case report in Owo, southern Nigeria described bilateral ectopia lentis without any family history. Delayed presentation was a notable finding.⁸ Marfan’s syndrome has also been reported in association with retinitis pigmentosa in a 24-year old man.¹⁰

Non-traumatic ectopia lentis, may occur in isolation but it is commonly associated with syndromes such as Marfan’s syndrome, homocystinuria and Weill– Marchesani syndrome.¹² It is estimated that 1 in every 5000 individuals is affected by Marfan’s syndrome.¹³ Non-syndromic cases may be sporadic or familial. Some syndromic associations of ectopia lentis may sometimes be life-threatening. Mitral valve prolapse, mitral regurgitation, aortic dilatation, aortic dissection, and aortic regurgitation are features that could be associated with significant cardiovascular mortality and morbidity.¹⁴ Therefore, a detailed systemic examination is pertinent for proper diagnosis, management, and prognostication. Some genetic mutations are known to be associated with specific phenotypic features hence correlating the phenotype with the genotype is useful in medical management algorithms.¹⁵ Genetic analysis could identify mutations that are not associated with extraocular manifestations hence refuting a need for extensive systemic investigations in the affected individuals.¹⁶ This makes genetic testing a very important tool in the management of ectopia lentis. Some common ocular features of ectopia lentis include mild to severe visual impairment, double vision, strabismus, and refractive errors. Other clinical features such as amblyopia, cataract, secondary glaucoma, and retinal detachment can markedly impair quality of vision with profound visual morbidity.¹³ Irrespective of the severity at initial presentation, the degree of the ectopia lentis and the disease progression with time vary among affected individuals.¹⁷

Management options include conservative measures using optical correction with spectacles or contact lenses, and surgical methods.^12,18 Classical indications for surgical therapy include situations where the lens edge bisects the pupil, making it impossible to achieve a good optical correction; and an anteriorly displaced lens causing secondary glaucoma.¹⁷ Lensectomy is the most commonly performed surgical intervention and the approach (pars plana versus limbal) depends on the surgeon’s expertise, as no study has shown a superiority of either approach.¹⁹

Visual rehabilitation following surgery can be challenging and may require multiple interventions and long term follow up. Options for visual rehabilitation include iris fixated intraocular lens (IOL), Scleral fixated IOL, as well as posterior chamber IOL insertion with the use of capsular tension rings (CTR).^{18– 25} Contact lenses and aphakic spectacles are alternatives to IOLs but also have significant challenges.^17,21 Aphakic spectacles are heavy, have accompanying prismatic distortion, constricted fields, scratch and may need frequent replacement while contact lenses could lead to neovascularization, may predispose to cornea infection, and both could be associated with noncompliance.²⁶ Also, the cost of contact lenses may be prohibitive in our resource-constrained setting.

The possible sequalae of amblyopia, glaucoma and retinal detachment in children make early identification and prompt management vital for better outcomes.¹⁷ This is especially important in our environment where delayed presentation and financial constraints may adversely affect outcomes. Ectopia lentis although rare is a cause of avoidable blindness in the paediatric age group. Not much is known about the outcome of care in sub-Saharan Africa as only few case reports have been described in literature. Therefore, the aimof this study was to describe the clinical profile of a cohort of patients with non-traumatic ectopia lentis in a paediatric ophthalmology clinic in Ibadan, Nigeria with the aim of adding to the body of knowledge on this condition in sub–Saharan Africa.