Axial Length of the Eye?, AXL, IOL master? A-scan, ultrascan

👁 What is Axial Length of the Eye?

Axial Length (AXL) refers to the distance from the anterior corneal pole to the posterior scleral pole—
essentially the front-to-back length of the eyeball.

 

 

---

🧬 Basic Eye Anatomy

• Cornea (anterior 1/6):
  • Radius: ~8mm
• Sclera (posterior 5/6):
  • Radius: ~12mm
• The eye is a non-perfect sphere, composed of two fused spherical parts.

 

 

---

📏 Axial Length Growth

AgeAxial Length

At birth	~18mm
Age 3	~23mm
Age 14+	~23–24mm

• Rapid growth occurs in early childhood
• Final adult size is usually reached in teenage years
• Influenced by refraction type (myopia/hyperopia), race, gender, measurement method

---

🔍 Findings from Korean Studies

YearSubjectsMean AXLMethod

1983	170 adults	23.5–23.99mm	A-scan ultrasound
1990	150 adults	23.0–23.49mm	A-scan
2003	150 adults	23.939mm	Partial Coherence Interferometry (IOL Master)

---

✅ Summary

• Normal adult axial length: 23–24mm
• May vary with age, sex, refraction type, and equipment used
• Accurate AXL is crucial in cataract surgery, myopia control, and refractive analysis