Cataract and Its Causes

A cataract is a light-scattering opacity within the lens that can lead to visual loss when it obstructs the visual axis.

Cumulative exposure to UV radiation and smoking are two environmental factors contributing to age-related cataracts.

Ocular trauma, including blunt and penetrating injuries, can lead to the development of cataracts by causing direct damage to the lens.

<p>Systemic diseases can contribute to cataract formation through various pathways, potentially exacerbating the effects of aging and environmental factors.</p> Signup and view all the answers

<p>Uveitis can lead to unilateral cataract formation if it affects one eye, causing inflammation that impacts the lens.</p> Signup and view all the answers

<p>Near vision causes miosis, which reduces pupil diameter and creates more obstruction from the cataract, leading to poorer vision.</p> Signup and view all the answers

<p>An immature cataract is partially opaque, while a mature cataract is completely opaque.</p> Signup and view all the answers

<p>A hypermature cataract has a shrunken and wrinkled anterior capsule due to water leakage from the lens.</p> Signup and view all the answers

<p>Common symptoms include painless loss of vision, glare from light scattering, and changes in refraction.</p> Signup and view all the answers

<p>Cataracts appear as a dark silhouette against the red reflex, aiding in diagnosis and determining the need for surgery.</p> Signup and view all the answers

<p>The primary indication for cataract surgery is visual improvement when daily activities are impacted by visibility loss.</p> Signup and view all the answers

<p>A nuclear cataract may cause a myopic shift, leading to nearsightedness and difficulty with distance vision.</p> Signup and view all the answers

<p>A Morgagnian cataract is a type of hypermature cataract where liquefaction allows the nucleus to sink inferiorly.</p> Signup and view all the answers

<p>Medical indications arise when a cataract adversely affects eye health, such as causing phacolytic or phacomorphic glaucoma.</p> Signup and view all the answers

<p>Fundus examination helps monitor or treat conditions like diabetic retinopathy, which may require improved clarity provided by cataract surgery.</p> Signup and view all the answers

<p>A cover test may indicate heterotropia, suggesting amblyopia or a risk of diplopia if vision is improved.</p> Signup and view all the answers

<p>Conditions like dacryocystitis, blepharitis, and chronic conjunctivitis must be resolved to prevent endophthalmitis.</p> Signup and view all the answers

<p>Eyes with decreased endothelial cell counts are at higher risk of postoperative decompensation due to surgical trauma.</p> Signup and view all the answers

<p>A shallow anterior chamber can lead to difficulties in creating a capsulorrhexis and may require additional mydriatic measures.</p> Signup and view all the answers

<p>Nuclear cataracts are harder and may need more power for phacoemulsification, whereas cortical opacities are generally softer.</p> Signup and view all the answers

<p>Assessing current refractive status guides the selection of an appropriate intraocular lens (IOL) implant.</p> Signup and view all the answers

<p>A Vossius ring is an imprint of iris pigment on the lens that results from blunt trauma and indicates a traumatic cataract.</p> Signup and view all the answers

<p>Systemic steroids and chlorpromazine can lead to posterior subcapsular cataracts.</p> Signup and view all the answers

<p>Chronic anterior uveitis can lead to the development of cataracts due to persistent inflammation affecting the lens.</p> Signup and view all the answers

<p>Congenital rubella infection is a systemic cause of cataract.</p> Signup and view all the answers

<p>Nuclear cataracts begin as an exaggeration of normal aging changes in the lens nucleus and often increase the refractive index.</p> Signup and view all the answers

<p>Glaukomflecken are anterior subcapsular opacities that occur due to acute angle-closure glaucoma.</p> Signup and view all the answers

<p>Down syndrome is one of the syndromes associated with cataract formation.</p> Signup and view all the answers

<p>Metabolic disorders such as galactosaemia and hypocalcaemia can cause lens opacities leading to cataracts.</p> Signup and view all the answers

<p>Congenital cataract can lead to bilateral amblyopia, squint, and nystagmus due to impaired retinal image formation during visual development.</p> Signup and view all the answers

<p>Urgent surgery is necessary to maximize the chances of successful visual development and to prevent amblyopia and other complications.</p> Signup and view all the answers

<p>Contact lenses correct aphakia but require substantial input and motivation from the child's parents to be effective.</p> Signup and view all the answers

<p>Surgery performed prior to one year of age carries a significant risk of developing subsequent glaucoma.</p> Signup and view all the answers

<p>Subluxation refers to a minor displacement of the lens, while dislocation indicates a more advanced or complete displacement.</p> Signup and view all the answers

<p>Inherited disorders like homocystinuria and Marfan syndrome can cause ectopia lentis due to defects in zonular proteins.</p> Signup and view all the answers

<p>Abnormal lens shape and ectopia lentis can cause the eye to become more rounded, resulting in increased myopia.</p> Signup and view all the answers

<p>Intraocular lenses are implanted, along with coordinated patching routines for the amblyopic eye.</p> Signup and view all the answers

<p>Keratometry readings are crucial for assessing the curvature of the anterior corneal surface, particularly for addressing astigmatism through targeted wound placement or adjunctive procedures.</p> Signup and view all the answers

<p>Biometry aids in calculating the lens power needed for the desired refractive outcome by measuring keratometry and axial length.</p> Signup and view all the answers

<p>The SRK-T formula is commonly used for calculating IOL power in eyes with axial lengths greater than 22.0 mm.</p> Signup and view all the answers

<p>Patients need to stop wearing contact lenses to allow for corneal stabilization, ensuring accurate measurements during biometry.</p> Signup and view all the answers

<p>Optical coherence biometry utilizes low-energy laser beams for non-contact axial measurements.</p> Signup and view all the answers

<p>The choice of IOL power is influenced by the refraction of the fellow eye and whether that eye also has a cataract requiring surgery.</p> Signup and view all the answers

<p>The Zeiss IOLMaster performs comprehensive biometry, measuring keratometry, anterior chamber depth, and calculating IOL power using various formulae.</p> Signup and view all the answers

<p>Analyzing postoperative refractive results helps identify any 'refractive surprises' and adjust future surgical strategies accordingly.</p> Signup and view all the answers

<p>Nuclear sclerosis initially appears with a yellowish hue due to urochrome pigment deposition, which can counteract presbyopia, potentially reducing the need for magnifying glasses.</p> Signup and view all the answers

<p>Cortical cataracts initially develop as vacuoles and clefts in the lens cortex, progressing to radial spoke-like opacities that commonly cause glare due to light scattering.</p> Signup and view all the answers

<p>Posterior subcapsular cataracts are located at the nodal point of the eye, leading to greater impairment of near vision compared to distance vision, unlike nuclear or cortical cataracts.</p> Signup and view all the answers

<p>Nuclear cataracts progress from yellow to brown due to increasing nuclear opacification and exaggeration of normal aging changes.</p> Signup and view all the answers

<p>Anterior subcapsular cataracts are characterized by fibrous metaplasia of the lens epithelium, which occurs directly under the lens capsule.</p> Signup and view all the answers

<p>Spherical aberration occurs when the outer parts of a lens do not focus light rays at the same point as the central part, leading to blurred vision.</p> Signup and view all the answers

<p>The initial appearance of clefts and vacuoles in cortical cataracts indicates early hydration changes in lens fibers, which can lead to vision complications.</p> Signup and view all the answers

<p>As individuals age, nuclear sclerosis can induce a temporary restoration of near vision, known as 'second sight,' despite its eventual progression to cataracts.</p> Signup and view all the answers

<p>A Vossius ring is caused by the imprinting of iris pigment onto the anterior lens capsule, usually due to blunt trauma or concussion.</p> Signup and view all the answers

<p>Drugs such as systemic or topical steroids and chlorpromazine are commonly associated with posterior subcapsular cataracts.</p> Signup and view all the answers

<p>Glaukomflecken are opacities on the anterior lens capsule that result from ischemic damage during acute angle-closure glaucoma.</p> Signup and view all the answers

<p>Nuclear cataract can lead to myopia due to an increase in the refractive index of the lens nucleus, causing changes in light refraction.</p> Signup and view all the answers

<p>Down syndrome is associated with congenital cataract, which can lead to significant visual impairment if not addressed early.</p> Signup and view all the answers

<p>Metabolic disorders like galactosaemia and hypocalcaemia disrupt lens metabolism, leading to opacification and cataract development.</p> Signup and view all the answers

<p>The main surgical approach is phacoemulsification, where an ultrasound probe is used to emulsify the lens through a small incision.</p> Signup and view all the answers

<p>Chronic anterior uveitis can cause prolonged inflammation, leading to complications such as cataract formation due to abnormal healing.</p> Signup and view all the answers

<p>Ionizing radiation can cause direct damage to the lens fibers, resulting in cataract formation over time.</p> Signup and view all the answers

<p>Patients must be informed about any coexisting eye disease that may affect the outcomes of cataract surgery and the visual prognosis.</p> Signup and view all the answers

<p>Potential symptoms include difficulty recognizing faces, reading, and experiencing significant glare.</p> Signup and view all the answers

<p>A toric intraocular lens is significant because it incorporates astigmatic correction, improving visual outcomes for patients with astigmatism.</p> Signup and view all the answers

<p>Local anesthesia is used to numb the eye area, allowing surgery to be performed while the patient remains awake.</p> Signup and view all the answers

<p>Innovations include the use of femtosecond lasers for making incisions and partially emulsifying the lens.</p> Signup and view all the answers

<p>Younger patients need to know they may experience sudden loss of active focusing, requiring an adjustment period.</p> Signup and view all the answers

<p>The plastic lens implant restores focusing ability, replacing the natural lens that was removed.</p> Signup and view all the answers

<p>Bilateral amblyopia can trigger the onset of squint.</p> Signup and view all the answers

<p>Surgery performed before one year of age significantly increases the risk of developing glaucoma.</p> Signup and view all the answers

<p>It is essential to stimulate visual maturation in the amblyopic eye and minimize the risk of squint.</p> Signup and view all the answers

<p>Ectopia lentis can lead to a more rounded lens shape, resulting in increased myopia.</p> Signup and view all the answers

<p>Complications include risks of developing glaucoma and potential issues with visual maturation.</p> Signup and view all the answers

<p>Homocystinuria is associated with ectopia lentis, causing downward displacement of the lens.</p> Signup and view all the answers

<p>It requires considerable input and motivation from the parents to ensure effective treatment for aphakia.</p> Signup and view all the answers

<p>It is characterized by bilateral, conical anterior protrusion of the anterior lens surface.</p> Signup and view all the answers