ORIGINAL: Relationship Between Average Keratometric (AK) Readings and Axial Length (AL) Measurements in A Sub-Saharan African Population

West Afr J Med. 2024 October; 41(10): 1023-1027 PMID: 40009825

Abstract

Aim: To report the relationship between average keratometric (AK) readings and axial length (AL) measurements in left eyes of patients attending a cataract surgery camp in sub-Saharan Africa.

Methods: A prospective evaluation of 648 left eyes of consecutive patients who presented for a cataract surgery camp. The KOWA Autorefractor and Alcon ocuscan were used for measurements. Left eyes alone were evaluated to reduce duplication of data. The data obtained were statistically analyzed using Statistical Package for Social Sciences, version 20.0 (SPSS v20).

Results: A total of 648 eyes of 648 patients were analyzed. There were 306 (47.2%) males and 342 (52.8%) females with age range from 11 to 95 years, mean ± SD age of 65.70 ± 14.28 years. AL range was from 18.00 mm to 30.39 mm, mean ± SD of 23.21± 1.19. AK ranged from 38.50 D to 48.50 D with mean ± SD of 43.41±1.68. AK reading of patients' left eye increased as the patients age increased (p=0.007). AK readings also increased with a reduction in AL (p=<0.001). Hence smaller eyes had steeper corneas. AL of left eye and AK readings were linearly related by: AL = 33.29 - 0.232AK.

Conclusion: Average keratometric readings in left eyes of our cohort of patients increased with age (p=0.007) and reducing axial length (p=<0.001). Axial length of left eye and Average-K readings are linearly related by: AL = 33.29 - 0.232AK. This formula can be utilized during cataract camps to estimate either value, used in intraocular lens calculations.