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Anterior chamber depth (expressed in millimetres) = -3.3 x EZ ratio + 4.2 This estimate has been shown to be accurate with a 95% confidence interval of +/– 0.33 mm error, when compared to measurements of the anterior chamber depth by Scheimpflug photography.
The Van Herick's technique has become the most commonly used qualitative method of assessing the size of the anterior chamber angle (ACA). Whereby, it involves comparing the depth of the peripheral anterior chamber to the thickness of the cornea, when a narrow beam is shone within the limbus at a 60°angle. [4]
True anterior chamber depth (ACD) is measured between the posterior corneal surface and the anterior lens surface. This measure is not to be confused with the anterior chamber constant (ACD constant) used in IOL power calculation formulas. [2] All lens constants are estimates, to begin with.
The anterior chamber angle is a part of the eye located between the cornea and iris which contains the trabecular meshwork. The size of this angle is an important determinant of the rate aqueous humour flows out of the eye, and thus, the intraocular pressure. The anterior chamber angle is the structure which determines the anterior chamber depth.
The depth of the anterior chamber and position of the posterior capsule may be maintained during surgery by OVDs or an anterior chamber maintainer, which is an auxiliary cannula providing a sufficient flow of BSS to maintain the stability of the shape of the chamber and internal pressure. [4] [9] [clarification needed]
Anterior chamber depth (ACD, i.e. the distance between the crystalline lens and cornea including the corneal thickness) is required before the surgery and measured with the use of ultrasound. Iris-fixated IOLs are fixated to iris therefore they have the advantage of being one size (8.5 mm).
Iridocorneal angle width: The width of the iridocorneal angle is one factor affecting the drainage of aqueous humour from the eye's anterior chamber.A wide angle allows sufficient drainage of humour through the trabecular meshwork (unless obstructed), whereas a narrow angle may impede the drainage system and leave the patient susceptible to acute angle-closure glaucoma.
The globe of the eye, or bulbus oculi, is the frontmost sensory organ of the human ocular system, going from the cornea at the front, to the anterior part of the optic nerve at the back. More simply, the eyeball itself, as well as the ganglion cells in the retina that eventually transmit visual signals through the optic nerve.