The effects of Mydrin-P on cornea and anterior segment structures in young myopic patients

Abstract

Objective To evaluate the effects of Mydrin P on cornea and anterior segment structures in young myopic patients.Methods One hundred and four eyes of 52 myopic patients were enrolled in the study.The mean age of the patients was 24.1+ 5.47 years old.There were 27 male and 25 female patients.The mean spherical equivalent was 4.1±5.07D.Mydrin P was instilled every 10 minutes for three times.Before and post 40 minutes,Orbsean IIz exam was performed in Zyoptix program,and transferred to Zyoptix Q value calculator to acquire Q value.Compared t test was used for statistical analyses using SPSS 11.0.A P value less than 0.01 was considered statistically significant.Results Before pupil dilated,the pupil diameter,anterior chamber depth(ACD),and cornea thickness were 4.52±0.71mm,3.09± 0.20mm,557.04+ 28.06mm respectively.After pupil dilated they were 8.09±0.53mm,3.15±0.19mm,544.42±28.20mm.There were statistically significant differences in all groups(P ＜ 0.01); Anterior best-fit sphere(BFS)were 7.88±0.21 mm,before Mydrin-P instilled,and 7.88±0.21mm,after that.The difference was 0.0001±0.056mm,95% CI was between -0.011 and 0.011.There were no significant differences(P =0.986).The posterior BSF were 6.42±0.20mm,and 6.44±0.20mm,before and after pupil dilated.The difference was 0.016±0.075mm,95%CI was -0.030～-0.001mm.There were no significant,difference(P =0.035).The anterior elevation difference value (AED)were 8.36 + 6.57μ m,and 8.59±4.35μ m The difference was 0.23±6.44μ m,95% CI was -1.48～-1.2μm,There were no statistically significant differences(P =0.716).The posterior elevation difference value(PED)was 28.56±27.29 and 29.13±28.79μ m pre and post pupil dilated.The difference was 0.577±38.5μ m.95%CI was -8.075～-6.922μ m.There were no significant difference(P =0.879).The 3mm diameter axial power was 43.79±1.20D and 43.85±1.21D pre and post pupil dilated.There were no significant differenees(t =-1.898,P=0.061).The 5ram diameter axial power were 43.41±1.13D and 43.48±1.15D.There were no significant differences(t=-2.592,=0.011).The angle kappa was 4.22±1.38° and 3.69±1.39°before and post pupil dilation.It reduced 0.732± 1.05°,95% CI was 0.529～0.936.There was significant difference(t=7.149,P=0.000).The Asphericity value(Q-value)was -0.179±0.11 before pupil dilated and -0.166±0.12 after pupil dilated.There were no significant differences(P =0.192).Conclusions Mydrin P can caused relaxed accommodation,but the corneal anterior and posterior best-fit sphere,the anterior and posterior elevation difference value,3mm,5mm axial power,and Q-value had no changes,but angle kappa decreased significantly. Key words: Mydrin-P,Accommodation,Corneal curvature,Best-fit sphere,Elevation Difference angle kappa,Q value