眼眶骨折眼球内陷功能性复位手术的临床观察

目的：研究眼眶骨折眼球内陷手术复位的方法和手术最佳时期，探讨手术前后视功能变化。方法：应用螺旋CT影像和视觉电生理检查技术对100例施行眼眶重建和眼球复位手术的患者进行观察研究。结果：在早期手术的40例患者中，28例眼球内陷完全复位，12例改善；60例晚期手术中，32例完全复位，28例得到部分改善；手术前后视网膜电流图（F—ERG）和视觉诱发电位（P-VEP）无显著性差异。结论：采用人工材料行眼眶重建和眶内充填技术手术治疗眼球内陷可获得满意的疗效，早期手术效果优于晚期手术，手术创伤对视功能无明显影响，眼眶重建和眼球复位手术是安全可行的。     

准分子激光原位角膜磨镶术患者主客观因素与疗效的相关性分析

目的：通过对准分子激光原位角膜磨镶术(LASIK)患者主客观因素与疗效的相关性分析，了解临床影响术后视力的主观、客观因素。方法：对2002年间在我院行ASIK的164例患者325只眼(其中3例为单眼)进行连续性临床观察研究，分别进行术前、术后问卷式主客观因素调查，并对患者手术疗效进行相关性统计学分析。结果：患者术前对手术效果的期望值、手术中疼痛程度与手术后视力有显著相关性。结论：解除患者术前忧虑及避免术中疼痛对提高术后疗效有重要意义。     

Users' subjective evaluation of electronic vision enhancement systems

The aims of this study were (1) to elicit the users' responses to four electronic head-mounted devices (Jordy, Flipperport, Maxport and NuVision) and (2) to correlate users' opinion with performance. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used these electronic vision enhancement systems (EVESs) for a variety of visual tasks. A questionnaire designed in-house and a modified VF-14 were used to evaluate the responses. Following initial experience of the devices in the laboratory, every patient took home two of the four devices for 1 week each. Responses were re-evaluated after this period of home loan. No single EVES stood out as the strong preference for all aspects evaluated. In the laboratory-based appraisal, Flipperport typically received the best overall ratings and highest score for image quality and ability to magnify, but after home loan there was no significant difference between devices. Comfort of device, although important, was not predictive of rating once magnification had been taken into account. For actual performance, a threshold effect was seen whereby ratings increased as reading speed improved up to 60 words per minute. Newly diagnosed patients responded most positively to EVESs, but otherwise users' opinion could not be predicted by age, gender, diagnosis or previous CCTV experience. User feedback is essential in our quest to understand the benefits and shortcoming of EVESs. Such information should help guide both prescribing and future development of low vision devices.     

Impaired cardiovascular autonomic function in Parkinson's disease with visual hallucinations.

We assessed the relations of visual hallucinations (VH) to cardiovascular autonomic dysfunction in patients with Parkinson's disease (PD). The subjects were 37 patients without VH (VH(-)) and 31 with VH (VH(+)). Autonomic function was evaluated on the basis of cardiac 123-radioiodinated metaiodobenzylguanidine (123I-MIBG) uptake and hemodynamic testing with Valsalva maneuver. Systolic blood pressure (SBP) and plasma norepinephrine concentrations (NE) were measured by tilt-table testing. 123I-MIBG uptake was lower in VH(+) than VH(-). Hemodynamic studies showed that VH(-) had only cardiac sympathetic and parasympathetic dysfunction, while VH(+) additionally had reduced vasomotor sympathetic functions. The fall in SBP during tilt-table testing was greater in VH(+) than VH(-). NE and its difference in the supine and upright positions were decreased in VH(+). We conclude that cardiac and vasomotor sympathetic dysfunction is more severe in VH(+) than in VH(-). Severe dysfunction in PD with VH is probably attributed to Lewy-body lesions or neuronal loss in sympathetic ganglia, the central autonomic system, or both.     

Age, lens transmittance, and the possible effects of light on melatonin suppression

Recently it has been suggested that a previously undetected, rhodopsin-based, visual pigment, located in some retinal ganglion cells and having a peak sensitivity around 460 nm, may be responsible for light-induced melatonin suppression and, perhaps, maintenance of the circadian rhythm. Using data from the literature, it is shown that, as absorption in the crystalline lens for shorter visible wavelengths increases substantially with age, while the pupil diameter tends to decrease, the effective retinal exposure received under the same ambient lighting conditions by the pigment is almost 10 times lower in an old, as compared with a young, eye. Interestingly, replacement of the old crystalline lens by an intraocular implant restores the exposure to youthful levels. The possible effects of these changes with age on circadian rhythms are discussed.     

The effect of observation time and contrast on visual acuity

Background: Field studies of the duration of fixation during daytime driving find that it is about 0.2 seconds on average. Thus, the time available to read traffic signs is often limited. There are other circumstances where time to read alphanumeric messages is limited. Data relating time of observation are needed for purposes of ergonomic design as the data available in the literature are limited and uncertain. Method: Visual acuity was measured using Landolt rings in negative contrast, which were presented on a computer screen with a background luminance of 32 cd/m2 for durations that varied between two and 0.02 seconds at three different contrasts. Resulte: Visual acuity depends on the log of the light dose reduced by a factor that may be related to absorption of the light by the eye media. For young observers, it was found that: VA = 0.57 (log C t) + 1.705, where C is the contrast and is expressed as δL/L, where δL is the difference between target and background luminances in cd/m2 and t is the observation time in seconds. Conclusion: This formula or the functions fitted to the data obtained can be used to calculate the increase in target size needed to allow for short observation times.     

Clinical Observation on Effect of Acupuncture in the Treatment of Optic Atrophy

Opticatrophy,acommondiseasewhichleadstoblindness,respondstofewtreatment.However,acupuncturehasbeenactuallyusedandtheclinicaleffectintreatingthisconditionisratherpreferable.Byusingtheacupunctureformula"Three--EyeNeedling",remarkableclinicaloutcomeisachievedandtheresultoftherelatedelectrophysiologicalparametersfollowingtheacupuncturepracticeintreatingopticatrophyhasbeenobserved.METHODSClinicalD8tsTheclinicalmaterialswerecollectedintheSpecialClinicofOpticAtrophyoftheDepartmentofAcupuncture…     

Neurons in the Primate Superior Colliculus are Active Before and During Arm Movements to Visual Targets

The activity of single neurons in the superior colliculus was recorded while a rhesus monkey made arm movements to visual targets located on a screen in front of him. It was found that the activity of a subpopulation of cells was clearly related to these arm movements. The neurons began to discharge either with the onset of the movement, during the movement period, or well before the onset of electromyogram (EMG) activity and movement, and could be active for the entire duration of EMG activity. While the discharge pattern of some of these'reach'neurons was not different for movements to different target positions, other cells showed graded changes in activity depending on the direction of movement. The peak discharge rate could rise to > 100 impulses/s. Some units received somatosensory input; other reach cells exhibited a visual response and/or presaccadic activity. It is likely that the primate superior colliculus is not only involved in the initiation and control of orientating movements of the eyes but also in reaching movements of the arms.     

Malignant chiasmal glioma: a rare cause of rapid visual loss

The clinical, neuroradiological, and histological findings of an adult patient suffering from malignant optic glioma is reported. Rapid visual deterioration was misdiagnosed for several months until biopsy confirmed the tumor. The patient died despite radiation therapy nine months after first symptoms. Our presentation will focus on the problems of diagnosing and establishing therapeutic procedures in this rare malignant neoplasm.