ABSTRACT
This paper introduces a novel focusing method Refraction Topography (RT) for wide-angle refraction measurement. The agreement of the test results obtained using RT is evaluated against simulation results and expected refraction. RT develops a refraction algorithm on fundus images at various focusing statuses. Unlike conventional techniques for peripheral refraction measurement, RT requires the subject to stare at a stationary fixation target. The refraction algorithm calculates the focus measure for multiple images at the Point of Interest and formulates them into a focus profile. The maximum focus measure correlates with the optimal focus position. Refraction Characterization Function (RCF) is proposed to translate the focus position into refraction determination, thus forming the refraction topography. The refraction characterization of RT optical system is performed using Isabel schematic eye. Three test eyes of - 15 D, 0 D, and + 15 D are defined, and expected refraction is obtained through simulation on an independent test schematic eye. Both simulation results and experimental results are obtained by combining the test eyes and RT system. Test results are compared with simulation results and expected refraction. The study demonstrates agreement among the test results, simulation results, and expected refraction on three test eyes.
ABSTRACT
Objective To assess the characteristic of normal tension glaucoma (NTG) patients with mild cogni?tive impairment (MCI). Methods This study included twenty-six cases of normal tension glaucoma patients who were diagnosed at ophthalmology department of Peking University Third Hospital. All the participants were examined by us?ing the scales of Montreal Cognitive Assessment (MoCA), mini-mental state examination(MMSE), clinical dementia rat?ing (CDR), activities of daily living (ADL), Hamilton anxiety scale (HAMA), Hamilton depression scale (HAMD), Pitts?burgh Sleep Quality Index (PSQI) and polysomnography (PSG). The patients were then divided into Group with MCI (16 cases) and Group without MCI (19 cases). Results There was no difference between the two groups in gender, age, edu?cation, depression, anxiety and body mass index (BMI) (P>0.05), but significant difference in MoCA scores (P0.05). The in?cidence rate of sleep structure disorder of PSG in all the NTG patients was 85.7%(30/35 patients), 87.5%(14/16 pa?tients) in Group with MCI, and 84.2%(16/19 patients) in Group without MCI. Sleep time of NREM-N3 was significant?ly shorter in Group with MCI than in Group without MCI (P0.05). Conclusion NTG patients with mild cogni?tive impairment are more prone to sleep disorders, especially sleep structure disturbance and short NREM-N3 time may affect cognitive function.
