Application of different OCT scanning patterns on detecting retinal nerve fiber layer thickness

Objective To investigate the influence of optic disc on the retinal nerve fiber layer(RNFL)thickness measured by three different optical coherence tomography(OCT)scanning patterns.Methods According to the optic disc area,156 eyes of 156 healthy subjects from 18 to 30 years old were divided into 3 groups,big disc group,middle disc group and small disc group.Using 3 kinds of OCT scan protocols[RNFL thickness(3.4),nerve head circle(0.98+optic radius)and RNFL thickness(2.27×disc)] to measure the 360° average RNFL thickness of three groups,respectively.The differences between each two groups were compared using the same OCT scanning pattern.The correlations between 360° average RNFL thickness measured by three OCT scanning patterns and the optic disc area were analyzed.Results The 360° average RNFL thickness measured by RNFL thickness(3.4)scanning pattern among three groups had statistically significant differences(F=23.762,P=0.000).The big optic disc group is the biggest one,the middle optic disc group is the next,the small optic disc group is the smallest one(P0.001).The 360° average RNFL thickness measured by RNFL thickness(2.27×disc)scanning pattern and nerve head circle(0.98+optic radius)scanning pattern among 3 groups had no statistically significant difference(F=0.738,P=0.416;F=1.091,P=0.339).A positive correlation was observed between the 360° average RNFL thickness measured by RNFL thickness(3.4)scanning pattern and the optic disc area(r=0.506,P=0.000).A negative correlation was observed between the 360° average RNFL thickness measured by RNFL thickness(2.27×disc)scanning pattern and the optic disc area(r=-0.290,P=0.001).No correlation was observed between the 360° average RNFL thickness measured by nerve head circle(0.98+optic radius)scanning pattern and the optic disc area(r=-0.005,P=0.949).Conclusions The influence of optic disc on RNFL thickness measured by RNFL thickness(3.4)scanning pattern is the biggest one.RNFL thickness(2.27×disc)scanning pattern and nerve head circle(0.98+optic radius)scanning pattern are following.More attention should be paid in clinical application.