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Purpose: To study correlation between ocular axial length and anterior chamber depth in eyes and to differentially analyse strength of this correlation in eyes with near-equal axial length. Materials and Methods: We conducted an observational study where keratometry and optical biometry records of 872 patients reporting for cataract surgery were taken. A comparative analysis using Optical Biometry (Zeiss IOL master) for pre-operative measurement of Axial length (AL), Anterior chamber depth (ACD) and calculated IOL power was done. Statistical Analysis: Data was analysed to determine overall correlation between two parameters. Patients were then classified into various groups of near-equal AL for a differential comparison within the group. Kendall-Pearson product-moment correlation test was used to assess relationship between AL and ACD, overall and within each subgroup. A P-value < 0.05 was considered as statistically significant. Results: 872 eyes were analysed and it was seen that as the mean AL (23.28mm), increased, mean ACD (2.97mm) also increased in overall analysis. In group analysis correlation between AL and ACD varied widely from 0.86 (AL-17-21 mm) to a negative -0.14 (AL 21-22mm). Conclusions: As mean AL increases ACD also increases. In eyes with near-equal AL there is wide variability in ACD which is either due to variable lens thickness or lens location in different eyes. Since lens thickness variability was obviated by taking age-matched eyes, location of lens is the probable cause. Therefore, Effective Lens Position (ELP) based formulae (Haigis & Holladay II) have an inherent unpredictability and may result in post-operative refractive surprises.