- Which of the following are causes of non-glaucomatous optic disc cupping-
a. Methanol toxicity
b. Intracranial tumours
c. Arteritic anterior ischaemic optic neuropathy
d. All of the above
- Optic nerve head morphology using EDI OCT in glaucomatous and non-glaucomatous cupping with large cup-to-disc ratios will have-
a. Anterior laminar depth values of the glaucoma group were greater than the Non glaucomatous cupping group
b. No difference was found between the glaucoma and Non-glaucomatous groups regarding lamina cribrosa thickness
c. Macular volume was reduced significantly in patients with non-glaucomatous cupping compared to patients with glaucomatous cupping
d. All of the above
- Which of the following is true?
a. Cupping is more profound in glaucoma
b. Glaucomatous eyes had greater degrees of neuro-retinal rim pallor
c. Vertically aligned visual fields defect is specific for non-glaucomatous optic disc cupping.
d. a and c
- What is Köllner’s rule?
a. Red–green colour defects are more often associated with changes in the outer retina.
b. Tritan defects are more often associated with optic nerve and central diseases
c. Both a and b
d. None of the above
- Which of the following is not a cause of pseudo-optic disc atrophy-
a. Myelinated retinal nerve fibers
b. Optic disc coloboma
c. Optic disc hypoplasia
d. Retinitis pigmentosa.
Answer 1. d ( All of the above)
Enlargement of optic disc cupping is most frequently associated with glaucoma. However, optic disc cupping is also seen in non-glaucomatous lesions, such as methanol toxicity, intracranial tumours, optic neuritis, dominant optic atrophy, periventricular leucomalacia and arteritic anterior ischaemic optic neuropathy.
Reference: Fard, M. A., Moghimi, S., Sahraian, A., & Ritch, R. (2018). Optic nerve head cupping in glaucomatous and non-glaucomatous optic neuropathy. British Journal of Ophthalmology, bjophthalmol 2018–0:1–5.https://www.ncbi.nlm.nih.gov/pubmed/29793928
2. d (All of the above)
Distant From the BMO plane to anterior surface of lamina cribrosa is known as the anterior laminar depth (ALD). The distance between the anterior and posterior borders of the highly reflective region of Lamina Cribrosa on enhanced depth imaging with the OCT was defined as the LC thickness.
Fard et al found that ALD values of the glaucoma group were greater than those of the non glaucomatous group when adjusted for age, axial length and Peripapillary choroidal thickness. LC thicknesses was thinner in both glaucomatous and non-glaucomatous eye than in the control eyes. ALD, is useful in differentiating NGC from glaucoma in eyes with advanced cupping.
Reference: Fard, M. A., Moghimi, S., Sahraian, A., & Ritch, R. (2018). Optic nerve head cupping in glaucomatous and non-glaucomatous optic neuropathy. British Journal of Ophthalmology, bjophthalmol 2018–0:1–5. https://www.ncbi.nlm.nih.gov/pubmed/29793928
In a study by Gupta et al the macular volume was reduced significantly in patients with non-glaucomatous cupping compared to patients with glaucomatous cupping. The findings of reduced macular thickness and volume may be explained by Wallerian degeneration. With disruption of axonal integrity, degeneration of the proximal axon segment occurs. Specifically, some lesions of the posterior optic nerve, such as a compressive mass lesion, have been reported to result in preferential damage to the smaller diameter macular axonal fibers traveling within the optic nerve . There may be preferential damage to the papillomacular bundle in non-glaucomatous optic neuropathies which could cause reduced macular thickness and volume.
Reference: K Gupta, Sanjay Asrani,Sharon F Freedman, Mays El-Dairi, and M Tariq Bhatti, Differentiating Glaucomatous from Non-Glaucomatous Optic Nerve Cupping by Optical Coherence Tomography. Open Neurol J. 2011; 5: 1–7.DOI: 10.2174/1874205X01105010001
Answer 3. The clinical differentiation of glaucomatous from non-glaucomatous cupping (NGC) can be difficult. Cupping was reported to be more profound in eyes with glaucoma. Disc pallor greater than cupping and vertically aligned visual field defects could predict non-glaucomatous causes of cupping. Reference: Fard, M. A., Moghimi, S., Sahraian, A., & Ritch. Optic nerve head cupping in glaucomatous and non-glaucomatous optic neuropathy. British Journal of Ophthalmology, bjophthalmol 2018–0:1–5. https://www.ncbi.nlm.nih.gov/pubmed/29793928
Greenfield and colleagues, found Optic pallor greater than cupping and vertically aligned visual field defects to be 90% and 81% specific for non-glaucomatous cupping respectively.
Reference: Greenfield DS, Siatkowski RM, Glaser JS, et al. The cupped disc—who needs neuroimaging? Ophthalmology 1998;105:2966–2974.DOI: 10.1016/S0161-6420(98)91031-4
Answer 4. d (none of the above)
Köllner’s rule posits that red–green colour defects are more often associated with optic nerve and central diseases, whereas tritan defects are more often associated with changes in the outer retina.
Yet, patients with optic neuritis have mixed colour vision changes and patients with glaucoma often show yellow–blue changes.
JS Werner, JL Keltner, RJ Zawadzki and SS Choi. Outer retinal abnormalities associated with inner retinal pathology in non-glaucomatous and glaucomatous optic neuropathies. Eye (2011) 25, 279–289 https://www.nature.com/articles/eye2010218
Answer 5. d (retinitis pigmentosa)
Non pathologic causes of a pale disc
• Disc is examined with very bright light
• Large physiologic cup in axial myopia
• Post-cataract extraction
Other (non optic atrophy) causes of a pale disc
• Myelinated retinal nerve fibers
• Optic disc coloboma
• Optic disc hypoplasia
Vivian B Osaguona. Differential diagnoses of the pale / white / atrophic disc . Community eye health journa.2016,29 (96),71-74. https://cehjournal.org/wp-content/uploads/differential-diagnoses-of-the-pale-white-atrophic-disc.pdf