Understanding Eye Defects: A Comprehensive Guide

Common eye defects, roughly by age of typical onset: myopia (near-sightedness) increasingly common in children — Indian data shows 30-40% of urban teenagers are now myopic, driven by high screen time and reduced outdoor play; corrected with concave lenses. Hypermetropia (far-sightedness) is often present from birth but manifests when eye strain rises during school years or adulthood; corrected with convex lenses. Astigmatism is an irregular corneal curvature causing distorted vision at all distances, usually detected in childhood, corrected with cylindrical lenses. Presbyopia is the age-related loss of near vision starting around 40 — universal, corrected with reading or progressive lenses. Cataract typically appears after 50, is near-universal by 70+, and is treatable with surgery. Glaucoma is optic-nerve damage from raised eye pressure — often silent, onset 40+, and a leading cause of preventable blindness. Diabetic retinopathy affects long-standing diabetics — India has the world's largest diabetic population, so annual dilated eye exams are essential after 5 years of type 2 diabetes. Age-related macular degeneration causes central vision loss after 60. Regular eye exams catch most of these early.

Recommended examination frequency by age and risk: children need their first exam at 6 months, then at age 3, and again at 5-6 (before school), with yearly checks after school entry if there's any refractive error or family history. Adults 20-40 with no problems can go every 2 years; annually if you wear glasses or contacts. From 40-60, annual eye exams are standard, more frequent if you're diabetic, hypertensive, or have a family history of glaucoma. From 60+, annual exams with dilated retina check. Diabetics need an annual dilated retinal exam from diagnosis onwards. If you have a family history of glaucoma, start annual intraocular pressure, visual field, and OCT checks from age 35. Free or subsidised eye camps run by NGOs like Sankara Nethralaya, Aravind and LV Prasad Eye Institute are widely available. Government hospitals also provide subsidised eye care.

Glasses are the safest option — no eye contact, easy to update prescription. Downsides are cosmetic preference, fogging with masks, and limits during sport. Contact lenses give better peripheral vision and don't fog, but carry infection risk if hygiene is poor (contact lens keratitis is a real concern in humid climates), can cause dry eyes, and are more expensive long-term. LASIK provides permanent correction using an excimer laser to reshape the cornea; suitable for myopia -1 to -10 D, hypermetropia +1 to +4 D, and astigmatism up to about 4 D. Requires a stable prescription for 1+ year and adequate corneal thickness (measured pre-op). SMILE is a newer keyhole approach with faster recovery. ICL (Implantable Collamer Lens) is used for very high prescriptions or thin corneas where LASIK isn't suitable — it's reversible. PRK is an older technique still useful when LASIK is contraindicated. Consider LASIK or SMILE if you're 21-45, have a stable refractive error, adequate corneal thickness, and are motivated to be glasses-free. Choose an experienced surgeon at a reputed centre — ask about their outcome statistics.