🔷 Myopia vs Hyperopia vs Astigmatism Combined Simulator

Myopia — When the Eye Focuses Light Too Early

Short placeholder: nearsightedness blurs distant objects from excess focusing power.

• 6–14: Typical onset age (Short placeholder note)
• ~30%: Global prevalence (Short placeholder note)
• −0.25 to −20D: Correction range (Short placeholder note)
• Concave: Lens type (Short placeholder note)

Why light converges before the retina

Short placeholder: elongated eyeball or steep cornea over-bends incoming light.

Hyperopia — When the Eye Focuses Light Too Late

Short placeholder: farsightedness blurs near objects from insufficient focusing power.

• Any age: Typical onset age (Short placeholder note)
• ~25%: Global prevalence (Short placeholder note)
• +0.25 to +10D: Correction range (Short placeholder note)
• Convex: Lens type (Short placeholder note)

Why light converges beyond the retina

Short placeholder: shortened eyeball or flat cornea under-bends incoming light.

Astigmatism — Two Focal Lines Instead of One Point

Short placeholder: an irregular cornea shape bends light unevenly across axes.

• Corneal curvature: Typical cause (Short placeholder note)
• ~30–40%: Global prevalence (Short placeholder note)
• Cylindrical: Correction type (Short placeholder note)
• With myopia/hyperopia: Common pairing (Short placeholder note)

Why light splits into two focal lines

Short placeholder: unequal corneal meridians create separate focal distances.

Combined Refractive Error Patterns

Short placeholder: myopia, hyperopia, and astigmatism can overlap in one eye.

• Myopic astigmatism: Common combo (Short placeholder note)
• Common in adults: Prevalence (Short placeholder note)
• Refraction test: Diagnosis tool (Short placeholder note)
• Sphero-cylindrical: Correction (Short placeholder note)

How multiple errors combine in one eye

Short placeholder: sphere and cylinder components are measured and summed.

Corresponding Lens Correction Types

Short placeholder: each refractive error is matched to a specific lens design.

• Concave (−): Myopia lens (Short placeholder note)
• Convex (+): Hyperopia lens (Short placeholder note)
• Cylindrical: Astigmatism lens (Short placeholder note)
• Sphero-cylindrical: Combined lens (Short placeholder note)

Matching lens shape to the underlying error

Short placeholder: lens curvature redirects rays back onto the retina.

Short placeholder: correct diagnosis of each error type guides precise lens choice.