Objective measurement of retinal function is essential in assisting in the diagnosis and evaluation of treatment results of several diseases afflicting the eye, such as glaucoma, hypertensive retinopathy, diabetic retinopathy, macular diseases such as central serous retinopathy, and toxic neuropathy, etc. The long term objective of the project proposed in this application is to develop a clinically useful confocal scanning laser ellipsometer to objectively assess in vivo retinal function by measuring the transient birefringence change in the retinal nerve fiber layer (RNFL) related to ganglion cell activity. During Phase I, we will design and build a prototype system, develop software for data processing and display, pursue the measurement of birefringence change related to ganglion cell activity in the RNFL, evaluate the sensitivity and reproducibility of the prototype system, and perform preliminary clinical studies.