______ is the fluid in the posterior chamber of the eye

Appeared in: DSSSB 14 August 2024

Explanation

Aqueous humor is the clear, watery fluid that fills the anterior segment of the eye.
The anterior segment includes both the anterior chamber (in front of the iris) and the posterior chamber (the small space between the iris and the lens).
It is continuously produced by the ciliary body, which is located in the posterior chamber.
Its primary functions are to nourish the avascular structures of the eye (like the cornea and lens) and to maintain intraocular pressure.

Option B: Perilymph is an extracellular fluid located within the bony labyrinth of the inner ear, not the eye. It is involved in the mechanisms of hearing and balance.
Option C: Vitreous humor is a gel-like substance that fills the large space behind the lens, known as the vitreous chamber or posterior segment. The question asks about the posterior chamber, which is a small space in front of the lens.
Option D: Endolymph is the fluid contained within the membranous labyrinth of the inner ear. Like perilymph, it is essential for hearing and balance, not vision.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the eye and its intraocular fluids as background academic context rather than a clinical decision trigger.
The balance between the production and drainage of aqueous humor determines the intraocular pressure (IOP). The normal range is typically 12-20 mmHg.
Impaired drainage of aqueous humor through the trabecular meshwork leads to increased IOP, which is the primary risk factor for glaucoma. Untreated glaucoma causes progressive, irreversible damage to the optic nerve, leading to vision loss.
A nurse may assist in measuring IOP using tonometry and administers eye drops (e.g., miotics, beta-blockers) that either decrease aqueous humor production or increase its outflow to manage glaucoma.

How to Approach the Question

This is a factual recall question testing knowledge of anatomy.
Identify the key anatomical terms in the question: 'fluid' and 'posterior chamber of the eye'.
Mentally recall or visualize a cross-section of the eye. Differentiate between the major segments and the smaller chambers.
Recognize that the lens divides the eye into an anterior segment (in front) and a posterior segment (behind).
Recall that the iris further divides the anterior segment into the anterior chamber and the posterior chamber.
Remember that aqueous humor fills both of these chambers, while vitreous humor fills the large posterior segment.

Concept Tested & Keywords

QA6uVnMonxvGYv3IOifVeK

E6 Pharmacology Nursing Lilley 11e Part 3 p. 256-258

E6 Physiology Guyton 4SAE Part 3 p. 145-147

Practise the full DSSSB 14 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.