Introduction
Various etiological factors have been described for optic disc swelling that range from infective to neoplastic. Early diagnosis and treatment are essential to save patient’s vision and in some cases patients life too. The literature search showed very few studies in India to determine the causes of optic disc swelling. In this study, we aimed to determine the common causes and clinical presentations of optic disc swelling in South Gujarat, the western part of India. Unilateral optic disc swelling can be encountered in cases associated with Optic neuritis, Non Arteritic Anterior Ischemic Optic neuropathy, compressive Optic Neuropathy, Retinal vein occlusion and Diabetic papillopathy. Bilateral optic disc swelling is often associated with papilloedema infiltrative optic neuropathy, toxic optic neuropathy and malignant hypertension.1
Materials and Methods
This cross sectional observational study was conducted at the department of Ophthalmology in a Tertiary care center in South Gujarat region of India from December 2018 to January 2020. The study population was comprised of 50 consecutive cases of optic disc swelling that were diagnosed at Department of Ophthalmology during the study period irrespective of sex, above 18 years of age. Amongst them 29 were male and 21 were female. Detailed and thorough ocular examination was performed to each and every patient included in the study which comprised of Acuity of vision, Color Vision, reaction of pupil, Examination on slit lamp, Examination of fundus with Indirect Ophthalmoscopy and 78D lens with Fundus photography. Blood investigations, OCT, Visual field testing and MRI was performed when required.
Papilloedema was diagnosed when there is an elevated intra cranial tension along with optic disc edema which was considered diagnostic criteria in our study. Optic neuritis was defined according to the criteria of Optic neuritis treatment trial (ONTT).2 Patients presented with Anterior Ischemic Optic Neuropathy were enrolled according to the criteria of Ischemic Optic Neuropathy Decompression Trial (IONDT).3 Diabetic papillopathy patients were enrolled when patients had optic disc swelling without raised Intra-cranial tension or any ocular inflammatory conditions with considerable optic nerve function. For papilloedema associated with other systemic ailments, disease specific diagnostic tests and clinical examinations were used.
Results
69 eyes of 50 patients of optic disc swelling were examined in this study which included 29 male patients and 21 female patients.
This study included most patients within the age group of 18years to 77 years. Maximum patients were between age group of 28 to 57 years (See Table 1, Table 2). In this study 23 patients with disc oedema had Optic neuritis which was found to be the most common etiology. Other etiologies were papilloedema(n=10), hypertensive retinopathy (n=4), Acute ischaemic optic neuropathy (n=3), Neuroretinitis (n=3), Diabetic Papillopathy (n=2), Traumatic Optic Neuropathy (n=2), CRVO (n=2), Vogt Koyanagi Harada Syndrome(n=1). (Table 3).
Clinical presentations of bilateral optic disc oedema included 19 patients. Etiologies of bilateral optic disc oedema were papilloedema (10 patients) followed by optic neuritis with 4 patients, hypertensive retinopathy with 4 patients and VKH syndrome with 1 patient. From the 10 cases of papilloedema, meningitis was present in 6 patients followed by intracerebral hemorrhage in 2 patients, empty sella syndrome in 1 patient and subarachnoid hemorrhage in 1 patient.
Diminution of vision was the most common clinical presentation followed by headache, floaters, diplopia or double vision and eye ache respectively (Table 4). Headache, which was seen in18 (36%) patients was the most common presenting symptom in patients of papilloedema. The patients diagnosed as optic neuritis, CRVO, neuroretinitis, diabetic papillopathy, anterior ischaemic optic neuropathy presented with diminution of vision as a prime clinical feature (n=31, 62%). optic Ocular pain was more common in optic neuritis patients and seen in 13 (26%) patients while 2 (4%) patients of neuroretinitis had complaint of floaters.
Discussion
Even though there have been multiple International studies which have been carried out on causes of Optic disc edema, in India there have been very few relevant studies regarding this. We aimed to find the clinical presentations and etiologies of Optic Disc Oedema at tertiary care centre in South Gujarat region of India. Our study has excluded old cases with optic atrophy and paediatric age group patients which becomes the limitation of this study. Strength of this study is that this study is one of the few cross-sectional observational studies performed in India on Etiologies and clinical presentations of Optic disc oedema.
Optic nerve compression and dysfunction resulting from long and tedious list of insults may lead to a partial arrest of axoplasmic transport which ultimately results in Optic disc oedema.4
The factors that can cause increase in the intracranial tension may result in optic disc oedema because the sub arachnoid space of brain is connected with sheath of optic nerve. The term papilloedema is exclusively used when optic disc oedema is associated with raised intra-cranial tension.
In this study, we encountered 3 cases of Non Arteritic Anterior Ischemic optic neuropathy and 3 cases of neuroretinitis. The pathophysiology for optic disc oedema in Non Arteritic Anterior Ischemic optic neuropathy is axonal ischaemia and capillary leakage in optic nerve head5 (Figure 1).
The term optic disc oedema or swelling is used when etiology of the disc oedema is other than raised intra-cranial tension. Optic neuritis was the commonest cause of optic disc swelling in our study which was followed by papilloedema, hypertensive retinopathy (Grade 4), neuroretinitis, CRVO, papillopathy associated with diabetes and Vogt Koyanagi Harada syndrome respectively. It is stated that occurrence of disc swelling in VKH was significantly correlated with age and disc morphology rather that severity of inflammation.6 (Figure 2). Severe choroidal inflammation secondary to circulatory disturbances of branches of short post. Ciliary artery and/or centripetal branches from peri papillary choroid along with crowded discs may cause axonal flow stasis and secondary axonal swelling of the optic nerve in patients of VKH.7
Dimness of vision was the most common presenting symptom in this study followed by headache, ocular pain, floaters and diplopia.
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