Application Of Adaptive Optics In Visual Field Micro-defects Evaluation

Perimetry, the evaluation of the visual field, is an important diagnostic method in ophthalmology. It provides crucial information for diagnosing and monitoring the progression of many eye diseases, especially for patients with glaucoma. The early diagnosis of micro visual field defects has always been a major bottleneck in clinical perimetry. Redundancy of stimulus used at present is the major obstacle:Instead of only stimulating micro part with visual defects, stimulus image projected on the retina makes diffusion and covers a larger area, because of wavefront aberrations of human eye, and the false responses may be answered.Adaptive optics(AO), which is first used in a high resolution telescope technology, provides an effective solution for stimulus redundancycontrol.With real time wavefrontsensing, control and correction by AO, the optical system overcomes the dynamic interference, tends to the best performance as a diffraction-limited system.An adaptive optics micro-perimetry system is developed, combining real time ocular aberrations correction and micro stimulus, the stimulusredundacy is greatly reduced. According to visual psychophysical theory, the threshold of visual field(VF) and the frequecy-of-seeing curve(FOSC) are measured by universal perimetry methods.By corperation with West China Hospital of Sichuan University, experiments are taken for evaluation of adptive optics micro-perimetry system(AOMP). The VF and FOS of normal eyes and cone dystrophy eyesare measured before and after ocular aberrations compensation. The experimental results indicate that ocular aberrations correction can greatly reduce the dispersed degree of stimulus so that the mean values of VF are depressed and the FOS move towards the left. The VF and FOS of subjects with low sensitivity caused by ametropia are measured, and the differences off to the normal eyes are much bigger after wavefront compensation, the features of low sensitivity are easier to be found. The VF of cone dystrophy eye is greater than that of normal eye. Advantages of the adaptive optics application in evaluation of micro visual field defects have been verified, further statisticalanalysis of large amount samples can makes adaptive optics micro-perimetry potential for early diagnosis of cone dystrophy and other diseases such as glaucoma and so on.