Ocular manifestations in adults with intracranial neoplasms attending the neurosurgical unit in Kenyatta National Hospital

Abstract

INTRODUCTION: Patients with intracranial neoplasm are routinely seen in Kenyatta National Hospital at the Neurosurgical Unit. Most patients however do not have a complete ophthalmologic assessment and are therefore not fully informed about their visual prognosis especially when the visual pathway is affected. AIM: The aim of this study was to determine the prevalence and pattern of ocular findings within this population. METHODOLOGY: It was a cross sectional hospital based study carried out at the Neurosurgical Clinic and Ward at the Kenyatta National Hospital. 60 adult patients diagnosed to be having intracranial neoplasm were recruited over a period of three months (November 2005 - January 2006). An ophthalmic examination consisting of Best Corrected Visual Acuity, colour vision, pupillary reactions to light, extra ocular motility, proptosis, diploplia and nystagmus was done. The anterior segment was examined using a Haag Streit Slit Lamp and the posterior by indirect ophthalmoscopy using a 90 Dioptre loupe. Visual field assessment was done using the Goldman Perimeter. RESULTS: 28 males and 32 females were recruited. The mean age was 37 years, the median 36 years and a range of 15 to 69 years. 44 (73%) patients complained of ocular symptoms, and 29 (48%) had had a previous ophthalmic assessment. The most common neoplasm was the suprasellar tumour with a total of 17 (28%) patients. 20 (33%) patients had some degree of visual impairment, 11 (18%) of these were blind. 8(13%) patients had monocular blindness. Abnormal colour vision was recorded in 34 (28%) eyes. Pupi lIary reaction was abnormal in 30 (50%) patients. 13 (21%) patients had strabismus, 10 (17%) had nystagmus, proptosis was noted in 6 (10%) patients and diplopia in 4 (7%). II (18%) patients had abducens nerve palsy. Papilloedema was a finding in 20 (33%) patients, and bilateral disc atrophy in 16 (27%) patients. Generalized constriction was the most common visual field defect seen in 23 (18%) eyes followed by homonymous hemianopia in 16 (27%) eyes. 45 (75%) patients were referred for routine follow-up in the eye clinic, 4 (7%) patients with severe visual impairment were referred for Low Visual Assessment. All the 11 (18%) blind patients were referred for rehabilitation. CONCLUSION. There is a higher prevalence of ocular manifestations in patients with intracranial tumours in our set up compared to centres in developing countries. The number of patients who had ophthalmic assessment before the study was low. Tumours located in close proximity with the anterior visual pathway are most likely to cause optic nerve compression and subsequent blindness. The most common encountered visual field defect is the generalised constriction which is non-specific for localising the site of the tumour. Patients who are blind as a result of intracranial neoplasms are not properly rehabilitated. There is no protocol for the referral of these patients to other specialised institutions offering Low Vision Assessment and rehabilitation services. RECOMMENDATION: Neurosurgeons should work closely with ophthalmologists to ensure complete assessment of patients with intracranial tumours both pre operative and post operative. Referral for Low Visual Assessment and Rehabilitation needs to be formalised. There should be in-patient rehabilitation services within Kenyatta National Hospital.