Correlation and Comparison of Anterior and Posterior Corneal Surface Parameters in Healthy Eyes

Purpose: To correlate and compare anterior and posterior corneal surface parameters like Kflat, Ksteep, Kavg, R1, R2, Ravg and astigmatism in healthy eyes. Study Design: Descriptive correlational study Place and Duration of Study: This study was conducted at Mayo Hospital, Lahore from June 2020 to Dec 2020.. Methods: This study included 176 subjects (86 males and 90 females) with mean age of 28.06±9.68 and 28.13±8.24 respectively. The data was collected through non-random convenient sampling technique by self-made proforma after taking patients’ consent. Anterior and posterior corneal parameters (Kflat, Ksteep, Kavg, R1, R2, Ravg and astigmatism) were measured with GALILEI G4. Pearson correlation test was used for correlation and independent sample t-test / Mann-Whitney U test was used for comparing means of anterior and posterior corneal parameters. Data was entered and analyzed in SPSS-21. Results: Mean of anterior and posterior corneal curvatures was 44.21±1.01 D and -6.22±0.19 D[p<0.001], Kflat was 43.76±0.99 D and -6.08±0.19 D [p<0.001] and Ksteep was 44.66±1.08 D, -6.34±0.21 D, respectively [p<0.001]. The anterior and posterior corneal curvature Ravg was 7.63±0.17 mm, 6.44±0.200 mm [p<0.001], mean R1 was 7.71±0.17 mm, 6.58±0.21 mm, [p<0.001] and mean R2 was 7.56±0.18 mm, 6.31±0.21 mm, respectively [p<0.001]. Anterior posterior corneal astigmatism was 0.90±0.55 D and -0.25±0.11 D, respectively [p<0.001].Anterior corneal parameters also show strong correlation with posterior corneal parameters. Conclusion: There are significant difference between corneal parameters of anterior and posterior surface. Strong correlation was also found in anterior and posterior corneal parameters except corneal astigmatism.