Age-Related Cataract

Age related (senile) cataract is opacification of the crystalline lens occurring with ageing, and it is the leading cause of reversible blindness worldwide.

• Prevalence rises from about 5 percent at age 50 to over 50 percent after age 80.
• Morphology: nuclear sclerosis (hardening, yellowing, myopic shift), cortical (spoke like wedge opacities), posterior subcapsular (central plaque near the posterior capsule), and mature or hypermature (Morgagnian) cataract with liquefied cortex.
• Risk factors: age, ultraviolet exposure, smoking, diabetes, corticosteroids, myopia, previous eye surgery or uveitis, alcohol excess, family history, and obesity.
• Pathogenesis: oxidative damage and protein aggregation in the lens fibres, with loss of lens transparency.

• Painless progressive blurring of vision, glare (especially with headlights), reduced contrast sensitivity, faded colours (yellowing), and monocular diplopia.
• Nuclear: second sight (temporary improvement in near vision because of myopic shift).
• Posterior subcapsular: early and marked glare and poor vision in bright light and at near.
• Reduced red reflex, lens opacity visible at the slit lamp, shallow anterior chamber in intumescent cataract.
• Complications of advanced cataract: phacolytic glaucoma (hypermature cataract leaking lens proteins), phacomorphic angle closure (swollen lens), lens induced uveitis.

• Visual acuity, pinhole, glare testing, contrast sensitivity; refraction.
• Slit lamp assessment of lens morphology and grading; pupil dilatation; examine for pseudoexfoliation, zonular weakness (phacodonesis), anterior chamber depth, and corneal endothelium.
• Dilated fundus examination to exclude other causes of reduced vision (macula, optic nerve); B-scan ultrasound if no view of the fundus.
• Biometry (optical or ultrasound): axial length, keratometry, anterior chamber depth for intraocular lens power calculation; macular optical coherence tomography in selected patients.
• Medications review: alpha blockers (tamsulosin) predisposing to intraoperative floppy iris syndrome, anticoagulants, antiplatelets.

• Indication: functional visual impairment affecting daily activities, driving, work, or safety; also medical indications (phacomorphic or phacolytic glaucoma, need to view the retina for diabetic or other retinal treatment).
• Non-surgical measures: updated refraction, brighter lighting, anti-glare lenses; no medical treatment reverses cataract.
• Surgery: phacoemulsification with posterior chamber intraocular lens implantation through a 2.2 to 2.8 mm clear corneal incision, under topical anaesthesia (proxymetacaine or lidocaine 1 percent intracameral) with or without sedation. Manual small incision cataract surgery is a cost effective alternative for dense cataracts.
• Preoperative: pupil dilation (tropicamide 1 percent, phenylephrine 2.5 percent, with NSAID such as nepafenac 0.1 percent), antiseptic with povidone iodine 5 percent to the conjunctival sac.
• Endophthalmitis prophylaxis: intracameral cefuroxime 1 mg in 0.1 mL, or moxifloxacin 0.5 mg in 0.1 mL at the end of surgery.
• Postoperative: prednisolone acetate 1 percent four times daily tapered over 4 weeks, a topical NSAID (nepafenac 0.1 percent three times daily or ketorolac 0.5 percent) for 4 weeks (more in diabetics, to reduce cystoid macular oedema), and an antibiotic drop (moxifloxacin 0.5 percent four times daily for 1 week).
• Special situations: small pupil (iris hooks, pupil rings), weak zonules (capsular tension ring), white cataract (trypan blue 0.06 percent staining of the capsule), pseudoexfoliation, and previous vitrectomy.
• Outcomes: about 90 to 95 percent achieve improvement to 6/12 or better when no other eye disease is present.
• Complications: posterior capsule rupture (about 1 to 2 percent), endophthalmitis (about 0.05 to 0.1 percent), cystoid macular oedema, posterior capsule opacification, retinal detachment, corneal oedema, dropped nucleus, and intraocular lens malposition.
• Second eye surgery within 1 to 4 weeks gives the best functional benefit when the second eye is also symptomatic.