Analysis of keratometry and axial length distribution in urban population of Gujrat, India

Aim: The aim of this study is to measure keratometry and axial length to get normative data for different age group population. That will help us to see for variation in corneal power and axial length in different age group, gender and between right and left eye. That will also allow us to compare this data with different ethnic population. Materials and Methods: The study was conducted with measurement of keratometry with keratometer and axial length with contact A scan biometry of 294 eyes of 147 patients. Age distribution of patients are 11 to 75 years. Patients were selected randomly from daily OPD. Changes in keratometry and axial length were calculated by using paired sample t test, independent sample t test and T- test assuming equal variances. Results: As per different age population normative data for keratometry in diopter in our age group A, B, C and D is mean±SD is 44.7082±1.4179, 44.3073±0.8552, 45.3186±1.4984 and 44.4210±1.2683 respectively. The normative data for axial length distribution in mm for the age group A, B, C and D is 23.089±1.0395, 22.5378±0.9570, 22.5561±0.8118 and 22.9575±1.0535 respectively. In present study there is no correlation between right and left eye keratometry and age as r value is (r=0.08, r=0.04)(p=0.29, p=0.59) (95% CI for r= -0.1961 to 0.1273 and 0.2203 to 0.1024). There is no co relation between right and left eye axial length and age as r value(r=-0.06, r=-0.03) (p=0.46, p=0.67) (95% CI for r = -0.1961 to 0.1273 and -0.2203 to 0.1024) In our study mean keratometric value for a given age group A, B, C, and D for right eye is 44.8006±1.5401 D, 44.2802±0.8156 D, 45.3727±1.4987 D and 44.3822±1.2437 D respectively. While mean keratometric value for left eye for a given age group is 44.6165±1.3084 D, 44.3345±0.9021 D, 45.2645±1.5135 D and 44.4597±1.309 D respectively. In paired t test for right and left eye keratometry difference is not statistically significant (p=0.6849)(95% CI -0.1192- 0.1810). For axial length mean±SD value for age group A, B, C and D for right eye is 23.0880±1.0910 mm, 22.5302±0.9724 mm, 22.6156±0.7861 mm and 22.9705±1.0636 mm respectively. While for the left eye axial length for group A, B, C and D is 23.0857±1.0069 mm, 22.5454±0.9532 mm, 22.4965±0.8416 mm and 22.9445±1.0585 mm respectively. In paired t test for right and left eye axial length difference is not statistically significant (p=0.1509)(95% CI -0.013- 0.089). In our study mean value for keratometry for a given age group A,B,C and D for male is 44.2076±0.5691 D, 44.1892±0.6806 D, 45.5231±1.3972 D and 44.0661±0.9158 D and for female is 44.2088±1.8045 D, 44.4050±0.9729 D, 45.1632±1.5669 D and 44.7561±1.4638 D respectively. Difference in right and left keratometry in male and female is not statistically significant as (p=0.1551,p=0.1281)(95%CI-0.7437 to 0.1195, -0.7629 to 0.0970) While for mean values for axial length for a given age group A,B,C and D for male 23.0546±0.8297 mm, 22.5447±1.1112 mm, 22.4497±0.8446 mm and 23.0464±1.0868 mm respectively. While for female is 23.1192±1.2303 mm, 22.5321±0.8211 mm, 22.6370±0.7849 mm and 22.8736±1.0292 mm respectively. Difference in right and left axial length in male and female is not statistically significant as (p=0.9698,p=0.9829)(95%CI-0.3163 to 0.3287, -0.3246 to 0.3177). Conclusion: This study provides normative data for keratometry and axial length distribution for different age group for West Indian population. Study will help to improve current biometry practice. Study also shows no any significant difference in keratometry and axial length values in different age group included in our study and also no any statistical significant difference between right eye and left eye and in gender too.