PURPOSE: To compare the characteristics of the pattern visual evoked potential (PVEP) in patients with severe visual loss and normal controls, and to demonstrate the range of PVEP parameters in normal Koreans. METHODS: The patients were divided into three groups according to visual acuity: group 1, ranging from no light perception to less than 0.02; group 2, ranging from 0.02 to 0.1; and group 3, ranging from 0.125 to 0.25. Group 4 was established as a healthy control group. The 95% confidence intervals (CIs) of the PVEP parameters were calculated for group 4. The PVEP parameters were compared among these four groups, and the amplitudes were evaluated with respect to the 95% CIs. We used the area under the curve to integrate the sensitivity and the specificity of the PVEP parameter quantitative values (7.01 to 9.57 microV and 6.75 to 10.11 microV). RESULTS: A total of 101 eyes were investigated. The 95% CIs of the P100 and N135 amplitudes of group 4 were 7.01 to 9.57 microV and 6.75 to 10.11 microV, respectively. The amplitudes of P100 and N135 were significantly higher in group 4 (p < 0.001). The P100 and N135 amplitude were below the 95% CI in all group 1 patients. The area under the curve of the P100 amplitude was the highest (0.789). CONCLUSIONS: No legally blind patient in the present study exhibited a value within the 95% CI of the controls. The P100 amplitude may be the best parameter for defining blindness in patients.
Adult ; Blindness/*physiopathology ; *Evoked Potentials, Visual ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Vision, Low/*physiopathology ; *Visual Acuity ; Young Adult

PURPOSE: To compare the characteristics of the pattern visual evoked potential (PVEP) in patients with severe visual loss and normal controls, and to demonstrate the range of PVEP parameters in normal Koreans. METHODS: The patients were divided into three groups according to visual acuity: group 1, ranging from no light perception to less than 0.02; group 2, ranging from 0.02 to 0.1; and group 3, ranging from 0.125 to 0.25. Group 4 was established as a healthy control group. The 95% confidence intervals (CIs) of the PVEP parameters were calculated for group 4. The PVEP parameters were compared among these four groups, and the amplitudes were evaluated with respect to the 95% CIs. We used the area under the curve to integrate the sensitivity and the specificity of the PVEP parameter quantitative values (7.01 to 9.57 microV and 6.75 to 10.11 microV). RESULTS: A total of 101 eyes were investigated. The 95% CIs of the P100 and N135 amplitudes of group 4 were 7.01 to 9.57 microV and 6.75 to 10.11 microV, respectively. The amplitudes of P100 and N135 were significantly higher in group 4 (p < 0.001). The P100 and N135 amplitude were below the 95% CI in all group 1 patients. The area under the curve of the P100 amplitude was the highest (0.789). CONCLUSIONS: No legally blind patient in the present study exhibited a value within the 95% CI of the controls. The P100 amplitude may be the best parameter for defining blindness in patients.
Adult ; Blindness/*physiopathology ; *Evoked Potentials, Visual ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Vision, Low/*physiopathology ; *Visual Acuity ; Young Adult

A 50-year-old man had undergone lumbar vertebral surgery and was confined to bed in the supine position for three months. When he sat up from the prolonged supine position, he showed clinical signs of orthostatic hypotension and reported decreased vision in both eyes. He also had underlying anemia. Ophthalmologic findings suggested bilateral anterior ischemic optic neuropathy (ION) as the cause of the visual loss. Although there are numerous reports of ION in the setting of hemodynamic compromise, such as systemic hypotension, cases of ION-associated orthostatic hypotension are very rare.
Acute Disease ; Blindness/diagnosis/*etiology/physiopathology ; Fluorescein Angiography ; Fundus Oculi ; Humans ; Hypotension, Orthostatic/*complications/physiopathology ; Male ; Middle Aged ; Visual Acuity

The latest development and the merit of using flexible neural microelectrodes are mainly reported in the paper, in which the properties of based-material, the micro-structure of neural microelectrodes and the method about how to test the microelectrodes are also included.
Blindness ; physiopathology ; rehabilitation ; Electric Stimulation Therapy ; instrumentation ; Electrodes, Implanted ; Evoked Potentials, Visual ; physiology ; Humans ; Microelectrodes ; Prosthesis Implantation ; Retina ; physiopathology

INTRODUCTIONOphthalmologists are occasionally confronted with an individual presenting with nyctalopia (i.e., a relatively greater difficulty seeing at night). When there is no accompanying abnormality seen in the fundus, visual electrophysiology becomes useful as an objective means of assessing rod (scotopic) photoreceptor function or pathway defects.

MATERIALS AND METHODSA retrospective study was performed on 50 consecutive patients, aged less than 40 years, with seemingly normal fundi and good vision [visual acuity (VA) >6/12] presenting to the Visual Electrodiagnostic Unit, Singapore National Eye Centre, for the investigation of nyctalopia over a 2-year period. Subjective scotopic threshold sensitivity (STS) and objective full-field electroretinogram (ERG) were performed. Persons with abnormal test results were identified.

RESULTSNormal ERG scotopic responses were obtained in 74% of subjects. There was no significant difference in age, refraction and STS levels between subjects with abnormal and normal ERG. In the group with abnormal scotopic ERG responses, 9 were identified to have nonspecific rod dysfunction, 2 had rod-cone dystrophies and 2 had ERG changes suggestive of congenital stationary night blindness (CSNB).

CONCLUSIONA large number of subjects presenting with nyctalopia had normal ERG findings. We can only assume that in these patients, no significant rod pathway dysfunction exists and that optical (e.g., night or instrument myopia) and psychological aetiologies should be considered. The fact that an abnormal result occurs in 26%, however, suggests that ncytalopia should be evaluated with electrophysiolgoical testing even when the fundi appear normal.

Adult ; Comorbidity ; Electroretinography ; Female ; Humans ; Male ; Night Blindness ; epidemiology ; physiopathology ; Refraction, Ocular ; Retinal Diseases ; epidemiology ; etiology ; physiopathology ; Retrospective Studies

Visual loss and field defects commonly occur after acute blood loss. We present a case of bilateral permanent visual field defect in a 30-year-old man after a massive hemorrhage caused by large vessel injury during a right nephrectomy. His postoperative visual acuity decreased significantly, and his visual field showed peripheral constriction and inferior altitudinal field defect in both eyes. A year and a half after the operation, visual acuity recovered to the preoperative level, but the field did not show improvement. We advance that this is a possible result of extensive injury to the occipital area, excluding the corresponding area of the macula.
Acute Disease ; Adult ; Blindness/*etiology ; Blood Loss, Surgical/*physiopathology ; Cerebral Infarction/complications/*etiology ; Humans ; Male ; Nephrectomy ; Occipital Lobe/pathology ; Vena Cava, Inferior/injuries ; Vision Disorders/*etiology ; *Visual Fields

Blindness ; etiology ; Embolism ; Endoscopy ; adverse effects ; Humans ; Male ; Middle Aged ; Paranasal Sinuses ; surgery ; Postoperative Complications ; Retinal Artery ; physiopathology ; Retinal Artery Occlusion ; complications ; etiology

PURPOSE: To report the long-term follow-up results after cyclocryotherapy, applied to the 3-o'clock and 9-o'clock positions in blind refractory glaucoma patients. METHODS: We retrospectively reviewed the charts of 19 blind patients, and a total of 20 eyes with refractory glaucoma who were treated with cyclocryotherapy. Cyclocryotherapy treatments were performed using a retinal cryoprobe. The temperature of each cyclocryotherapy spot was -80degrees C and each spot was maintained in place for 60 seconds. Six cyclocryotherapy spots were placed in each quadrant, including the 3-o'clock and 9-o'clock positions. RESULTS: The mean baseline pretreatment intraocular pressure (IOP) in all eyes was 50.9 ± 12.5 mmHg, which significantly decreased to a mean IOP at last follow-up of 14.1 ± 7.1 mmHg (p < 0.001). The mean number of antiglaucoma medications that patients were still taking at last follow-up was 0.3 ± 0.6. Devastating post-procedure phthisis occurred in only one eye. CONCLUSIONS: Cyclocryotherapy, performed at each quadrant and at the 3-o'clock and 9-o'clock position, is an effective way to lower IOP and, thus, is a reasonable treatment option for refractory glaucoma patients who experience with ocular pain and headaches.
Adult ; Aged ; Aged, 80 and over ; Blindness/etiology/*surgery ; Cryosurgery/*methods ; Female ; Follow-Up Studies ; Glaucoma/complications/physiopathology/*surgery ; Humans ; Intraocular Pressure/*physiology ; Male ; Middle Aged ; Retrospective Studies ; Time Factors ; Treatment Outcome ; *Visual Acuity

We report a very rare case of odontogenic orbital cellulitis causing blindness by severe tension orbit. A 41-yr old male patient had visited the hospital due to severe periorbital swelling and nasal stuffiness while he was treated for a periodontal abscess. He was diagnosed with odontogenic sinusitis and orbital cellulitis, and treated with antibiotics. The symptoms were aggravated and emergency sinus drainage was performed. On the next day, a sudden decrease in vision occurred with findings of ischemic optic neuropathy and central retinal artery occlusion. Deformation of the eyeball posterior pole into a cone shape was found from the orbital CT. A high-dose steroid was administered immediately resulting in improvements of periorbital swelling, but the patient's vision had not recovered. Odontogenic orbital cellulitis is relatively rare, but can cause blindness via rapidly progressing tension orbit. Therefore even the simplest of dental problems requires careful attention.
Adult ; Anti-Bacterial Agents/adverse effects/therapeutic use ; Blindness/*diagnosis/etiology ; Drainage ; Fluorescein Angiography ; Humans ; Male ; Optic Neuropathy, Ischemic/complications ; Orbit/*physiopathology ; Orbital Cellulitis/*diagnosis ; Retinal Artery Occlusion/complications ; Sinusitis/diagnosis/drug therapy ; Tomography, X-Ray Computed ; Tooth Root

This study examined the prevalence of primary open-angle glaucoma (POAG) among residents aged ≥50 years living in Yongchuan district of Chongqing. Stratified cluster sampling was employed in random selection to estimate the prevalence of glaucoma from April to June, 2005. Twenty-nine villages or neighborhood communities were randomly selected in urban area (Zhongshan Road), suburban area (Shanjiao Town) and exurban area (Zhutuo Town) of this district. All the respondents underwent detailed ophthalmic examinations. The examinations included questionnaire investigation, visual acuity test, naked-eye examination, measurement of peripheral anterior chamber depth (Van Herrick's technique), detection of intraocluar pressure (IOP) with a Perkins hand-held applanation tonometer (HA-2) and examination of the optic disc by using a 78 diopters (D) lens (including the cup-disc ratio, cup/disc ratio asymmetries, horizontal and vertical diameter, notching and optic disc hemorrhages). A total of 5938 residents were actually examined, and the response rate was 85.19%. The crude prevalence of POAG was 0.86% (n=51/5938, 95% CI 0.64%-1.11%). There were 24 males and 27 females in the glaucoma group. The glaucoma prevalence was not significant different in case number between the male and female subjects (P=0.4900). Furthermore, no association between age or schooling and POAG was noted (P=0.8030, 0.0734). Out of 51 subjects with POAG, unilateral glaucoma-related blindness occurred in 38 subjects (74.5%) and bilateral glaucoma-related blindness was found in 7 subjects (13.7%). This study exhibited that the prevalence of POAG was 0.86% among residents aged ≥50 years living in Yongchuan District of Chongqing. The vision loss caused by POAG in this population was obviously higher than that previously reported in other studies. Glaucoma management, detection of affected persons and handling of the burden of glaucoma should be the priorities of the agenda of local health authorities of Western China.
Aged ; Blindness ; diagnosis ; epidemiology ; China ; epidemiology ; Female ; Glaucoma, Open-Angle ; diagnosis ; epidemiology ; physiopathology ; Gonioscopy ; methods ; Health Surveys ; methods ; statistics & numerical data ; Humans ; Intraocular Pressure ; Male ; Middle Aged ; Prevalence ; Surveys and Questionnaires ; Vision Disorders ; diagnosis ; epidemiology