Optic atrophy – Not the end of the road always!

A 56-year-old healthy female noticed insidious onset of vision loss in the left eye (LE) with progressive worsening since 1 month. The best corrected visual acuity (BCVA) with Snellen’s visual acuity chart was 6/9, N6 in the right eye (RE) and 6/18, N8 in the LE. LE pupil had relative afferent pupillary defect (RAPD). The color vision using Ishihara pseudoisochromatic chart was 21/21 and 1/21 in the RE and LE, respectively. Anterior segment examination was unremarkable. Fundus examination showed LE optic disc pallor with well-defined margins and normal retinal vessels [Fig. 1]. Humphrey’s visual field (HVF) analysis with 30-2 program showed inferior altitudinal defect in the LE [Fig. 2]. Provisional diagnosis was LE NAAION. Since vision loss was insidious in onset and progressive in nature and the optic atrophy was primary, it led us to investigate further. Magnetic resonance imaging (MRI) of brain and orbit with contrast was suggestive of possible meningioma, causing left compressive optic neuropathy [Fig. 3]. The patient was referred to the neurosurgeon and underwent left frontal craniotomy with gross total resection of the tumor. Postoperatively, BCVA was 6/12, N8 and the color vision was 3/21 in the LE. HVF showed right homonymous hemianopia, and postoperative MRI Brain showed corresponding postoperative encephalomalacic changes in left fronto-temporal region.Figure 1: Fundus photograph showing normal disc features in the right eye (a) and optic disc pallor with a well-defined margin and normal retinal vasculature in the left eye (b). Retina and macula were apparently normal in both eyesFigure 2: Humphrey visual field testing with 30-2 pattern showed a few nonspecific nasal defects in the right eye and inferior altitudinal defects in the left eyeFigure 3: MRI Brain and Orbit with contrast: (a) coronal section and (b) axial section showing a lobulated homogeneous enhancing solid extra axial mass lesion in the left cavernous and paracavernous region encasing the left intracranial optic nerve suggestive of meningiomaDiscussion NAAION with typical features does not require neuroimaging.[1,2] Our patient had many features pointing towards NAAION, but the insidious onset of vision loss, absence of sectoral pallor or secondary optic atrophy, and absence of disc-at-risk in the contralateral eye were the red flag signs which raised the suspicion.[2–4] Compressive optic neuropathy can mimic symptoms and signs of NAAION.[3] But there was no history of headache and other neurological symptoms.[1,5] Visual field defects were not showing obvious patterns to favor a retrochiasmal defect. Our patient had mild improvement in visual acuity, though she had newer field defects which could be explained by the corresponding postoperative changes. This case highlights the importance of identifying the type of optic atrophy and then clinically correlate before labeling it as NAAION. Conclusion Optic atrophy may be the only presenting sign of intracranial lesion. Careful history taking and meticulous optic disc evaluation play a crucial role in identifying the red flag signs for an early diagnosis and prompt treatment. Authors' contributions Vijayalakshmi Arunagirinathan: Concepts, Design, Definition of intellectual content, Data acquisition, Manuscript preparation; Durga Priyadarshini Santhakumar, Design, Manuscript editing, Manuscript review; Smita Praveen, Data acquisition. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship: Nil. Conflicts of interest: There are no conflicts of interest.