Analysis of correlative factors effecting on diopter in myopia / 眼科

ABSTRACT

Objective To study the correlations between diopter,axis length,cornea curvature and thickness in myopia patients. Design Prospective case series.Participant 300 myopic patients who were ready for LASIK.Method 300 myopic patients who were ready for LASIK were selected randomly.They were divided into four groups according to the diopter of myopialow myopia group (≤-3.00D)41 cases,medium myopia group(＞-3.00D,≤-6.00D)130 cases,high myopia group(＞-6.00D,≤-9.00D)95 cases,and super myopia group(＞-9.00D)34 cases.The axis length,cornea thickness,cornea eurvture and diopter of myopia were detected. Through analysis of variance(ANOVA),Pearson correlation analysis and linear regression analysis,the correlations between axis length, cornea thickness,curvature and diopter of myopia were made out in four groups.Main Outcome Measure Diopter of myopia,cornea curvature,axis length of eye and central cornea thickness.Result The axis length of low myopia group,medium myopia group,high myopia group and super myopia group was(24.32?1.73)mm,(25.33?1.49)mm,(26.04?1.92)mm,(27.47?2.57)mm respectively. There were obvious differences of axis lengths between four groups(P=0.000).The cornea curvature in high myopia group was obviously different from those in low myopia group and medium myopia group.There were no significant differences of cornea thickness among four groups(P=0.409).The axis lengths of eyes respectively had correlations with diopters(r=0.734,P=0.000),vertical and horizontal cornea curvatures(r=-0.312,P=0.000;r=-0.328,P=0.000).Conclusion The main effective factor on the diopter of myopia is the axis length for most patients.For the patients with high myopia,the cornea curvature is another effective factor.With the increase of axis length,the cornea curvature decreases,and the cornea turns flatter.(Ophthalmol CHN,2006,15321-323)