Chronic Vision Loss
Reversible
Cataracts
- Any opacity of the lens, regardless of etiology
- Most common cause of reversible blindness worldwide
- Types: nuclear sclerosis, cortical, posterior subcapsular
Aetiology
Refractive Error
Corneal Dystrophy/ Scarring/ Oedema
- Acquired
- Age-related (over 90% of all cataracts)
- Cataract associated with systemic disease (may have juvenile onset): Diabetes mellitus, Metabolic disorders (e.g. Wilson's disease, galactosemia, homocystinuria), Hypocalcemia
- Traumatic (may be rosette shaped)
- Intraocular inflammation (e.g. uveitis)
- Toxic (steroids, phenothiazines)
- Radiation
- Congenital
- High myopia
- Present with altered red reflex or leukocoria
- Treat promptly to prevent amblyopia
- Gradual, painless, progressive decrease in VA
- Glare, dimness, halos around lights at night, monocular diplopia
- "second sight" phenomenon - patient is more myopic than previously noted, due to increased refractive power of the lens (in nuclear sclerosis only)
- Patient may read without previously needed reading glasses
- Diagnose by slit-lamp exam, and by noting changes in red reflex using ophthalmoscope
- May impair view of retina during fundoscopy
- Medical: attempt correction of refractive error, no strong evidence suggesting benefit of vitamin supplementation
- Surgical: definitive treatment
- Indications for surgery:
- Functional impairment
- Aid management of other ocular disease (e.g. cataract that prevents adequate retinal exam or laser treatment of DR)
- Congenital or traumatic cataracts
- RD, endophthalmitis, dislocated IOL, macular edema, glaucoma
- With new foldable IOLs that have truncated edges, <10% of patients get posterior capsular opacification, which is treated with YAG laser
- Excellent if not complicated by other ocular disease
Refractive Error
Corneal Dystrophy/ Scarring/ Oedema