Cataracts, macular degeneration and glaucoma: three very different problems

Vision loss in older adults is associated with falls, fractures, depression, social isolation, driving cessation and cognitive decline. It is also, in a large proportion of cases, either preventable or treatable — and the most treatable one is the most common.

Cataract

The lens gradually becomes cloudy, scattering light. Symptoms are progressive blurring, glare — particularly headlights at night — reduced contrast, faded colours, and sometimes an odd temporary improvement in near vision as the lens changes shape, occasionally called second sight.

Cataract is the leading cause of reversible blindness worldwide. Surgery involves removing the lens by phacoemulsification and replacing it with an intraocular lens; it is typically day surgery under local anaesthetic and takes twenty minutes or so, with success rates above 95 per cent.

Two points are worth emphasising. First, the timing threshold is functional, not anatomical — the question is whether the vision is interfering with what you want to do, not how the lens looks. Waiting until it is "ripe" is outdated advice.

Second, cataract surgery reduces falls. Several studies have found a reduction in fracture rate after first-eye surgery, and the effect is large enough that visual assessment belongs in any falls workup.

Age-related macular degeneration

AMD affects the macula, the small central area of retina responsible for detailed vision. Central vision degrades while peripheral vision remains — so people with advanced AMD can usually still walk around independently but cannot read, recognise faces or drive.

Dry AMD accounts for around 85 to 90 per cent of cases. It progresses slowly over years through drusen accumulation to geographic atrophy. There is no widely available treatment that restores vision; complement inhibitors that slow the growth of geographic atrophy have been approved in some countries and their clinical significance is debated.

Wet AMD is less common and far more aggressive — abnormal vessels grow beneath the retina and leak, causing rapid central vision loss over weeks. This is the treatable one. Anti-VEGF injections into the eye have transformed the prognosis, and outcomes depend heavily on how quickly treatment starts.

Risk factors for AMD progression include smoking — the strongest modifiable one, roughly doubling risk — hypertension, and genetics. The AREDS2 formulation of antioxidants and zinc reduces progression to advanced AMD in people with intermediate disease in at least one eye. It does not help those with early or no AMD, and the original beta-carotene formulation increased lung cancer risk in smokers, which is why the reformulated version substituted lutein and zeaxanthin.

Glaucoma

Progressive optic nerve damage, usually but not always associated with raised intraocular pressure. The common open-angle form is insidious: it takes peripheral vision first, painlessly, and the brain fills in the missing areas so effectively that people typically notice nothing until a substantial proportion of the visual field has been lost.

Vision lost to glaucoma does not come back. Treatment prevents further loss, which is why detection before symptoms is the entire game.

Screening happens through routine optometry — visual field testing, optic disc examination, intraocular pressure and increasingly OCT imaging of the nerve fibre layer. This is the practical argument for regular eye examinations even when vision seems fine, typically every two years and annually over seventy or with risk factors.

Risk factors: age, family history — a first-degree relative raises risk severalfold — African or Caribbean ancestry for open-angle glaucoma, East Asian ancestry for angle-closure, high myopia, diabetes, and long-term steroid use.

Treatment is usually eye drops to lower pressure, with laser trabeculoplasty increasingly used as first-line — the LiGHT trial found it at least as effective as drops with better outcomes and fewer patients needing surgery. Adherence to drops is notoriously poor, and it matters.

Acute angle-closure glaucoma is different and is an emergency: severe eye pain, headache, nausea, vomiting, blurred vision with haloes around lights, and a red eye with a fixed mid-dilated pupil. It causes rapid permanent damage and needs immediate treatment.

Diabetic retinopathy, briefly

The leading cause of blindness in working-age adults and a significant one later. It is asymptomatic until advanced, which is why annual screening for everyone with diabetes exists and why attendance matters. Glycaemic and blood pressure control both reduce progression; laser and anti-VEGF treatment are effective when needed.

The practical summary

Have a proper eye examination every two years, annually after seventy. Report sudden distortion, sudden loss, flashes and floaters, or eye pain the same day. Do not accept declining vision as simply age — most of it has a name and several of the names have treatments.

And if someone is having falls, check their glasses. Out-of-date prescriptions and, in particular, varifocals worn while walking are among the more fixable contributors to a fractured hip.