NON-GLAUCOMATOUS OPTIC NEUROPATHY IN IBADAN: EXTRAPOLATIONS TO HEALTHCARE FUNDING IN NIGERIA.

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OA Ogun and OA Adediran

Department of Ophthalmology, College of Medicine, University of Ibadan Neuroophthalmology Unit, Department of Ophthalmology, University College Hospital, Ibadan.

Abstract

Background: Optic neuropathy is not a diagnosis in itself, as potential aetiologies are myriad. A pilot study conducted in the Eye Clinic, University College Hospital, Ibadan, between September 2007 and
November 2009, showed that 46.8% of new cases presenting to the
neuroophthalmology unit, had non-glaucomatous optic neuropathy (NGON) in which, the precise aetiology of optic neuropathy was never diagnosed.

Methods: All cases of NGON, seen in the neuro-ophthalmology unit, between September 2007 and June 2014 were analyzed to determine common aetiologies and identify the difficulties encountered in their investigation or management.

Results: There were 159 cases of NGON. The age range was 6 months to 87 years (mean 39.0, SD 21.3). Male: Female ratio was 1.2: 1, and the commonest diagnosis was optic atrophy of unknown aetiology. Challenges identified included difficulty obtaining recommended radiological and serological investigations, as well as no access to genetic studies and high loss to follow-up.

Conclusion: There are major constraints in the investigation of patients
presenting with optic nerve disease in Ibadan, despite the prevalence of
NGON as a major cause of visual disability among neuro-ophthalmic patients in this setting. Diagnostic constraints must be addressed, to facilitate neuroophthalmology patient care, within our limited resources.

Keywords: Optic atrophy, Non-glaucomatous optic neuropathy, Neuroophthalmology, Aetiology, Healthcare funding, National health insurance

Introduction

With an estimated population of 5.58 million according to 2006 official Nigerian census, the landmass of Ibadan makes it the largest city in South-Western Nigeria but the third largest metropolitan city¹. The University College Hospital, Ibadan, is the largest teaching hospital in Nigeria, a major referral Centre, and Federal Government designated Centre of Excellence in the Neurological sciences². The Eye clinic, receives a large number of walk-in patients and secondary referrals. Subspecialty consultation clinics, like the Neuroophthalmology clinic, were established in September 2007.

An unpublished review of the first 27 months in the neuroophthalmology unit revealed optic neuropathy as the commonest presentation. Though, optic neuropathy is not a diagnosis in itself, as it results from various aetiologies³, some cases of optic neuropathy are amenable to treatment with good visual outcome^4,5.

Optic neuropathy is a significant cause of visual impairment among Nigerians⁶. A study in the Low Vision Clinic in Ibadan showed that the third commonest condition among 193 patients attending over a 3-year period was optic atrophy⁷. Retinitis pigmentosa (16%) and albinism (13.2%) especially among children, were the commonest conditions associated with optic atrophy in these cases ⁷. Compressive optic neuropathy is a preventable and treatable cause of visual loss and this was identified as the commonest cause of optic atrophy in a retrospective review of 100 randomly selected cases, by Oluleye et al.⁸. Aetiology of optic atrophy could not be identified in 62% of patients, in the review in question⁸. On the other hand, in Port Harcourt, in a review of 99 patients with NGON, 40% of patient had optic atrophy at presentation⁹. Majority of the patients in the Port Harcourt study were presumed to have nutritional amblyopia (31.3%) or demyelinating optic neuritis (27.3%) although 41.4% were undiagnosed9. Likewise, in many patients, in the neuroophthalmology clinic in Ibadan, determining the cause of NGON is challenging. Nevertheless, good management of such patients must involve early diagnosis and targeted therapy, where possible.

The objective of this study therefore was to determine the pattern of non-glaucomatous optic neuropathies presenting to the neuroophthalmology unit at the Eye clinic, University College Hospital, Ibadan and to perform a needs analysis to identify and recommend potential strategies for improving diagnostic patient evaluation and outcome of care.