This study evaluates the various ocular parameters which are necessary for ocular biometry and the calculated IOL powers using both dual Schiempflug analyzer and optical low-coherence refelctometry.

The measured keratometry, axial length, anterior chamber depth, lens thickness, white-to-white corneal diameter, and calculated IOL powers using various formulas including Hoffer Q, Holladay I, SRK II and SRK T measured by dual Schiempflug analyzer and optical low-coherence refelctometry will be compared.

Inclusion Criteria:

• axial length between 21.0 and 27.0 mm
• older than 20 years old

Exclusion Criteria:

• other ophthalmic diseases such as severe dry eye, glaucoma, and age-related macular degeneration
• previous ophthalmic surgery including cataract surgery, and refractive surgery
• very dense media which cannot be measured by the optical biometries
• severe zonulysis

140 eyes of patients who scheduled for cataract surgery