AIM: To report the application of asymmetric parameters of retinal nerve fiber layer and macular thickness in early diagnosis of primary open angle glaucoma.

METHODS: The clinical study included 100 eyes of 50 normal subjects and 100 eyes of 50 unilateral early primary open angle glaucoma. The mean field defect(MD)and pattern standard deviation(PSD)were recorded using a Humphrey perimeter. All eyes underwent Cirrus HD-OCT for thickness of total, inferior, superior retinal nerve fiber layer(RNFL)and macular, then calculated their intereye differrence and intraeye difference respectively(posterior pole asymmetry parameters analysis). The area under curve(AUC)was calculated for all OCT parameters.

RESULTS:In addition to the difference in the intraocular RNFL thickness around optic disc(P=0.265), the parameters of the RNFL thickness, macular thickness, intereye differrence of superior / inferior / total macular thickness, intraocular superior / inferior difference of macular thickness were statistically significant(P<0.05). The AUC of the total thickness of RNFL was 0.827. The sensitivity of the intereye RNFL thickness difference was the highest, with a 95% specificity of 67%. The mean AUC of the total macular thickness was 0.822. The AUC of the intereye difference of macular thickness was 0.777.

CONCLUSION: The asymmetric analysis of retinal thickness in the posterior pole provides a good diagnostic performance for patients with early POAG, similar to the diagnostic accuracy of RNFL thickness. However, intraocular asymmetric analysis parameters perform poorly and require further refinement before they are used for early unilateral glaucoma diagnosis.