Lens Anatomy and Structures

The capsule of the lens is thickest in the equatorial zone.

The subcapsular epithelium is responsible for producing new lens fibers throughout life.

The lens capsule is responsible for moulding the lens substance during accommodation, allowing the lens to change shape and focus light onto the retina.

<p>The capsule needs to be thicker in the equatorial zone due to the increased stress from the lens fibers that are being produced there.</p> Signup and view all the answers

<p>The subcapsular epithelium is only found under the anterior and equatorial capsule, as this is where new lens fibers are formed. The posterior capsule is located behind the lens in the vitreous cavity, and new lens fibers are not added there.</p> Signup and view all the answers

<p>Using a large plus lens in an aphakic eye for previously emmetrope or hypermetrope individuals can result in a 30% magnification of the retinal image, leading to aniseikonia, difficulty with fusion, and binocular diplopia.</p> Signup and view all the answers

<p>Aniseikonia</p> Signup and view all the answers

<p>Glasses are not recommended for unilateral aphakia with an emmetrope fellow eye because they would require a large plus lens for the aphakic eye, causing retinal image magnification and aniseikonia, leading to fusion difficulties and binocular diplopia.</p> Signup and view all the answers

<p>To prevent aniseikonia, which is caused by the magnification of the retinal image in the aphakic eye due to the large plus lens.</p> Signup and view all the answers

<p>Binocular diplopia, or double vision.</p> Signup and view all the answers

<p>Visual impairment and medical conditions like lens induced glaucoma.</p> Signup and view all the answers

<p>To block the ciliary ganglion, providing anesthesia to the iris and ciliary body while paralyzing the extraocular muscles.</p> Signup and view all the answers

<p>Complications can include retrobulbar hemorrhage and globe perforation.</p> Signup and view all the answers

<p>The two main components are cortex, which contains new soft lens fibers, and nucleus, which consists of older hard lens fibers.</p> Signup and view all the answers

<p>The anterior Y-shaped suture is erect, while the posterior Y-shaped suture is inverted, indicating the meeting of lens fibers.</p> Signup and view all the answers

<p>Phacoemulsification uses ultrasonic vibrations to break down the lens, whereas ECCE involves a large incision to remove the lens.</p> Signup and view all the answers

<p>General anesthesia is typically used for children and psychoneurotic patients.</p> Signup and view all the answers

<p>As the lens ages, it increases in weight and thickness while its accommodative power decreases.</p> Signup and view all the answers

<p>Crystallins make up 80% of the lens composition and help achieve transparency by minimizing light scatter as organelles are lost.</p> Signup and view all the answers

<p>A cataract is a condition characterized by the opacification of the lens, which can affect vision irrespective of its effect on clarity.</p> Signup and view all the answers

<p>Intumescent cataracts can cause phacomorphic glaucoma due to swelling of the lens and subsequent shallow anterior chamber.</p> Signup and view all the answers

<p>The absence of a red reflex suggests opacity in the optical media, such as cataracts, which can affect vision.</p> Signup and view all the answers

<p>Water accumulation in the lens leads to the breakdown of lens proteins and causes the lens to swell, becoming intumescent.</p> Signup and view all the answers

<p>The stretched capsule in an intumescent cataract results from the swollen lens, which can further complicate the anterior chamber's condition.</p> Signup and view all the answers

<p>A shallow anterior chamber can lead to increased intraocular pressure, which may cause phacomorphic glaucoma in patients with intumescent cataracts.</p> Signup and view all the answers

<p>The clinical features include a painful red eye, high IOP, shallow AC with a closed angle, dilated fixed pupil, and lens opacity.</p> Signup and view all the answers

<p>Phacolytic glaucoma is associated with a hypermature cataract and presents with deep AC with floating lens material, while phacomorphic glaucoma features a shallow AC due to a swollen lens.</p> Signup and view all the answers

<p>The main management strategies include medically decreasing IOP followed by cataract surgery.</p> Signup and view all the answers

<p>Parents may notice leukocoria, which is a white pupillary area indicating large and dense opacity.</p> Signup and view all the answers

<p>Zonular cataracts are strongly hereditary, bilateral, and appear as an opacified layer surrounding a clearer center within the lens.</p> Signup and view all the answers

A protective layer surrounding the lens, involved in its shape and function.

The capsule is thickest in the equatorial zone of the lens.

The capsule is thinnest at the posterior pole of the lens.

A single layer of cells under the capsule, absent at the posterior pole.

Cells in the equatorial region divide to produce new lens fibers continually.

The lens grows in both anterioposterior and equatorial dimensions throughout life.

The lens nucleus consists of older hard lens fibers, surrounded by newer soft fibers in the cortex.

Lens transparency is achieved through loss of organelles and tight arrangement of fibers, along with high crystallin content.

The lens refracts light, provides accommodation, absorbs UV radiation, and maintains clarity.

Cataract is the opacification of the lens, leading to any congenital or acquired opacity irrespective of visual impact.

A condition where the normal red reflex from the eye is missing, indicating potential issues.

A type of cataract where the lens swells and causes the capsule to stretch due to protein breakdown.

A secondary glaucoma caused by a swollen intumescent cataract leading to shallow anterior chamber.

A condition where the space between the cornea and lens is reduced, often seen in intumescent cataracts.

The process where lens proteins deteriorate, leading to cataract formation and swelling.

Includes painful red eye, high IOP, shallow AC, dilated pupil, and lens opacity.

Secondary open-angle glaucoma associated with hypermature cataract causing lens protein leakage.

Cataracts present at birth or developing early; occurs in about 3:10,000 live births.

Hereditary cataracts affecting specific lens zones; appear bilateral with clear centers.

A condition where one eye is without a lens, often after cataract surgery.

An individual with normal vision, no refractive error, both eyes can focus clearly.

A strong convex lens used to correct hyperopia or aphakia, increasing image size.

A condition where there is a difference in image size perceived by each eye, causing discomfort.

Double vision occurring when both eyes do not align properly.

Reasons to perform cataract surgery include visual impairment and medical conditions like lens-induced glaucoma.

Anesthesia method aimed at blocking ciliary ganglion to numb the iris and ciliary body, paralyzing extraocular muscles.

Temporary paralysis of the orbicularis muscle achieved through a facial nerve block.

A surgical technique with a large incision to remove the cataract while preserving the posterior capsule.

A modern cataract surgery technique that uses ultrasonic vibrations to break down and remove the cataractous lens.