Differences in Axial Length and Anterior Chamber Depth among Keratoconic, Myopic and Emmetropic Eyes.

Purpose: To report variation of the axial length (AL) and anterior chamber depth (ACD) among keratoconic (KC) eyes compared to myopic and emmetropic eyes in an African population sample. Study Design: Cross sectional observational. Place and Duration of Study: Al-Faisal Eye Hospital at Khartoum state of Sudan from January 2022 to September 2022. Methods: One-hundred and twenty-four eyes of 62 patients were divided into KC group (n =17, eyes = 34), myopic group (n = 28, eyes = 56), and an age/gender matched emmetropic group (n = 17, eyes = 34). Central corneal thickness (CCT) was measured using ultrasonic pachymeter, AL, ACD and keratometry readings (K-reading) were recorded for each patient using non-contact partial coherence interferometry with an IOL Master. Results: Mean age of the sample population was 22.27 ± 6.05 (range; 10 - 40 years). KC patients had the highest spherical equivalent of refraction (SER) (-6.19±3.91 dioptres), highest k-reading (48.98±5.68 dioptres) and the thinnest CCT. Myopic participants had a longer AL compared to other refractive error groups (AL = 24.99 ± 2.39, p < 0.001). KC patients exhibited a larger ACD in comparison to emmetropes and myopes (ACD=3.69 ± 0.26, p < 0.001). Among all participants, SER exhibited the highest correlation with AL (r = -0.71, p < 0.001) followed by a weaker correlation with ACD (r= -0.26, p = 0.003). However, among KC patients, SER exhibited a weaker correlation with AL compared to myopes (r = -0.55, p = 0.001), and a higher correlation with ACD compared to myopes (r= -0.38, p = 0.03). Conclusion: ACD and corneal curvature were the most significantly detrimental parameters in KC. KC participants demonstrated a lower correlation between SER and AL and higher correlation between SER and ACD. [ABSTRACT FROM AUTHOR]