Mustafa Abdul Hameed Ismail, Sabeen Chaudhry.
Keratometry, axial length and intra-ocular lens power variations observed during biometry.
Isra Med J Jan ;7(3):164-7.

OBJECTIVES: To document the variations in keratometry, axial length of eye and intra-ocular lens (IOL) power observed during biometry of cataract patients and to find any significant gender difference. STUDY DESIGN: A retrospective review of the biometry records. st st PLACE AND DURATION: Saeed Eye and Medical Complex, Rawalpindi from 1 Nov 2010 to 31 Dec 2014. METHODOLOGY: Patients of senile cataract were included from the biometry records. Keratometry readings of vertical and horizontal corneal meridian (K1 & K2) were measured with automated keratometre and axial length was measured with contact A-scan. Power of IOL was calculated by using SRK-T formula in patients with axial lengths between 22 and 26, Hoffer Q for axial lengths <22mm and Haigis for axial lengths >26 mm with A-constant of 118. The data was analyzed with SPSS version 16. RESULTS: 908 patient records were analyzed. The mean ±SD keratometry readings (K1 and K2) were 43.46 ±1.68 D and 44.41±1.98 D respectively. The mean ±SD axial length was 23.45±1.20mm. SRK-T was used in 818 (90.1%) cases, Hoffer Q in 68 (7.5%) and Haigis in 22 (2.4%) of cases. The mean ±SD intra-ocular lens power was 20.22±3.06D. Gender based comparison showed that the mean ±SD K1 in males (42.95 ±1.54D) was less than 43.88 ±1.67D for females (p=0.0001). The mean ±SD K2 for males (43.9 ±1.66D) was also less in females (44.78 ±1.70D) (p=0.0001). The mean ±SD axial length of eyes in males was 23.81 ±1.23mm significantly more than 23.16 ±1.08mm in females (p=0.0001). The mean ±SD IOL power was 19.68 ±3.19D in males and 20.67 ±2.86D in females (p=0.0001). CONCLUSION: The mean keratometry readings (K1 and K2) were 43.46 ±1.68 D and 44.41±1.98 D respectively. The mean axial length was 23.45±1.20mm and mean intra-ocular lens power was 20.22±3.06D. Gender based analysis showed that females have more keratometric readings but shorter axial lengths than males and required more power of IOL to be implanted after cataract surgery.

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