Visual field

• Q: Where is visual sensitivity greatest?

• A: In the center, decreasing toward the periphery

• Q: Give an example of a generalized visual field defect A: Retinitis pigmentosa

• Q: Give an example of a localized visual field defect A: Central scotoma from AMD

• Q: What is a scotoma? A: An area of depressed visual function (central, paracentral, cecocentral)

• Q: What is a sector-shaped defect? A: From small scotomas to complete sector loss (e.g., nasal optic disc defects)

• Q: What is an altitudinal defect? A: Affects superior/inferior quadrants, respecting the horizontal meridian

• Q: What is an arcuate defect? A: Narrow temporally, spreading nasally (e.g., glaucoma)

• Q: What is hemianopia? A: Loss of one half of the visual field (homonymous or heteronymous)

• Q: What is bitemporal hemianopia? A: Temporal loss of both eyes, usually involving the chiasm (e.g., pituitary tumor)

• Q: What is quadrantanopia? A: Defects in one quadrant of the visual field

Q: List common causes of retinal defects

• Congenital (e.g., coloboma)

• vascular (e.g., ischaemia), inflammation (e.g., uveitis)

• hereditary (e.g., retinitis pigmentosa)

• systemic (e.g., MS), degeneration (e.g., retinal detachment)

• Q: List some causes of optic disc/nerve pathology

• A: Congenital issues, neuropathy (e.g., optic neuritis), oedema, tumors, glaucoma

• Q: What types of visual field defects can result from optic disc/nerve pathology? A: Scotomas, arcuate defects, or complete unilateral VF loss

• Q: What pathologies can affect the optic chiasm and what visual field defects do they cause?

• A: Pituitary tumors (causing bitemporal hemianopia) or aneurysms, causing characteristic visual field defects (junctional scotoma)

Q: What type of visual field defects do optic tract lesions cause?

A: Homonymous hemianopias, often asymmetric (incongruous defects)

• Q: What is the function of the LGB in the visual pathway?

• A: It's the first synapse for retinal fibers

• Q: What types of visual field defects can LGB lesions cause?

• A: Sector-shaped defects or hemianopias, often affecting the macula

• Q: How are optic radiations divided?

• A: Into superior and inferior groups

• Q: What type of visual field defects do optic radiation lesions cause?

• A: Quadrantanopias, often due to temporal/parietal/occipital lobe damage

• Q: What types of visual field defects do visual cortex pathologies produce?

• A: Congruous VF defects (hemianopias, keyhole defects, macular sparing)

• Q: What are common causes of visual cortex pathologies?

• A: Vascular lesions, trauma, tumors

• Q: What is Static Perimetry?

• A: Measures retinal sensitivity using stationary lights

• Q: What is Kinetic Perimetry?

• A: Moving stimuli from non-seeing to seeing areas to map visual fields

• Q: What are some examples of Automated Perimetry devices?

• A: Octopus 900, Humphrey, Goldman

• Q: What is Confrontation testing?

• A: Manual tests (finger counting, hat pin method)

• Q: What are some key steps in performing automated perimetry?

• A: Ensure glasses are removed, calibrate machine, and maintain head/eye position

• Q: How do kinetic and static tests differ in automated perimetry?

• A: Kinetic tests map points seen by the patient; static tests vary brightness to assess sensitivity

Potential Artefacts in Visual Field Testing

• Q: What factors can interfere with visual field test results? A: Lenses, cataracts, pupil irregularities, and poor positioning

Confrontation Testing

Q: What is confrontation testing and how is it performed? A: It's a simple bedside method using finger counting