SEARCH · PubMed Health

Results for “Visual function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,531 records · Page 85Linked to original sources

PubMed2005

Vision and falls.

Falls occur in about one third of older people living independently in the community every year. This can lead to significant physical, psychological and financial costs to the individual and the community. While the risk factors for falls in older people are multifactorial, poor vision is considered to be an important contributing factor. The aim of this review is to evaluate current research linking impaired visual function with falls and to review current intervention strategies for the prevention of falls in older individuals. The evidence from the current literature indicates that impairment of visual functions, such as visual acuity, contrast sensitivity, visual fields and depth perception, is associated with an increased risk of falls. Recent studies have also demonstrated that falls can be reduced following cataract surgery as a visual intervention. Optometrists need to be aware of these associations and through appropriate treatment, referral and/or education, they can play a major role in optimising visual function in older people, as part of a multidisciplinary approach to falls prevention.

Accidental Falls↗

PubMed1995

Hypomorphic mutations in the larval photokinesis A (lphA) gene have stage-specific effects on visual system function in Drosophila melanogaster.

Of the many genes that are expressed in the visual system of Drosophila melanogaster adults, some affect larval vision. However, with the exception of one X-linked mutation, no genes that have larval-specific effects on visual system structure or function have previously been reported. We describe the isolation and characterization of two mutant alleles that define the larval photokinesis A (lphA) gene, one allele of which is associated with a P-element insertion at cytogenetic locus 8E1-10. Larvae that express lphA mutations are, like normal animals, negatively photokinetic, but they are less responsive to white light than lphA + controls. Larvae that are heterozygous in trans for a mutant lphA allele and a deficiency that uncovers the lphA locus are blind, which indicates that the mutant allele is hypomorphic. lphA larvae respond normally to odorants and taste stimuli. Moreover, the lphA mutations do not affect adult flies' fast phototaxis or visually driven aspects of male sexual behavior, and electroretinograms recorded from the compound eyes of lphA/deficiency heterozygotes and lphA1/lphA2 females are normal. These observations suggest that the lphA gene affects a larval-specific aspect of visual system function.

Animals↗

PubMed1993

Examination methods for glaucoma prevalence surveys.

OBJECTIVE: To perform a pilot evaluation of new examination methods for the detection of glaucoma and other causes of visual impairment in rural East Africa. DESIGN: Testing was performed by local eye nurses after a brief training course. Two novel tests of visual function were used, a scotopic sensitivity test and a visual field test performed on a laptop computer. The optic disc was examined with direct ophthalmoscopy after pupillary dilation and compared with standard photographs on a laminated card. Intraocular pressure was measured with a hand-held, electronic tonometer. SETTING: Rural Tanzania. PARTICIPANTS: One hundred twenty adult villagers. RESULTS: The visual function tests could be performed on more than 90% of subjects, and the results were correlated with the size of the optic disc cup, an objective measure of glaucoma injury. CONCLUSIONS: This survey shows the practicality of instrument-based testing of visual function under field conditions.

Adult↗

PubMed1984

Photophysiological functions of visual pigments.

In order to gain a fundamental understanding of functions of a visual pigment, i.e., photoreception and phototransduction, it is essential to elucidate the molecular structure of visual pigment, its photochemical behavior and connection of the pigment to the molecular physiological amplification mechanism for excitation of a visual cell. A rhodopsin, a rod visual pigment, is composed of an 11-cis-retinal bound with an apo-protein, opsin, through a protonated Schiff-base. Competitive inhibition of beta-ionone on regeneration of rhodopsin from an 11-cis-retinal and cattle opsin demonstrated the existence of a hydrophobic linkage between the beta-ionone ring of the retinal and the hydrophobic region of opsin. Owing to these two linkages, the 11-cis-retinal is fixed in an opsin cleft. As a result, it is endowed with new physiological functions as a chromophore of rhodopsin; the change of 11-cis-retinal (lambda max = 369 nm, epsilon = 26,400) to rhodopsin (lambda max = about 500 nm, epsilon = 40,600) brings not only a spectral shift from near ultraviolet to visible regions and an intensification of the molecular extinction coefficient, but also an increase of a quantum yield of 11-cis-retinal to all-trans form. High quantum yield of rhodopsin suggests rapid formation of the first photoproduct. Study of the first photoproduct was accelerated by the finding of bathorhodopsin, which was formed by irradiation at liquid nitrogen temperatures. The change of rhodopsin to bathorhodopsin has been inferred to be due to a photoisomerization of the chromophore from 11-cis to a twisted all-trans form. This isomerization hypothesis has been verified by the following experimental results. Irradiation of 7-cis- and 9-cis-rhodopsins at liquid nitrogen temperature produced the same bathorhodopsin as that from 11-cis-rhodopsin, indicating that the chromophore of bathorhodopsin should be in all-trans or transoid form. 7-Membered-rhodopsin, in which the rotation of 11-12 double bond of the retinylidene chromophore is locked, did not form bathorhodopsin by excitation of picosecond laser photolysis. This fact indicates that bathorhodopsin is a product formed by photoisomerization of the chromophore. Rhodopsin showed a positive circular dichroism (CD) in the visible while bathorhodopsin showed a remarkable negative CD. The reversal of the sign of CD indicates that not only large conformational change of the retinylidene chromophore occurs during the conversion of rhodopsin to bathorhodopsin, but also the direction of twist of the chromophore reverses. It is inferred that the chromophore of bathorhodopsin is a twisted trans form.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2004

Effects of verteporfin therapy on central visual field function.

PURPOSE: To evaluate the effect of photodynamic therapy with verteporfin on the maintenance of central visual field function. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: Forty-six consecutive patients with subfoveal choroidal neovascularization (CNV) caused by age-related macular degeneration including a classic component were randomly assigned. Thirty-three participants received standard verteporfin therapy, and 13 received placebo and laser treatment. METHODS: The trial was performed as a single-center, double-masked study. Patients were examined before therapy and continuously in 3-month intervals during 2 years of follow-up. A scanning laser ophthalmoscope (SLO) was used to perform macular microperimetry. Absolute and relative scotomas were documented at each visit, and size was measured in square millimeters. MAIN OUTCOME MEASURES: The change in size of central scotoma in the verteporfin group compared with the placebo group. RESULTS: An absolute scotoma was seen in 88%, and a relative scotoma was seen in 100% of eyes before therapy. Absolute defects were associated with the classic CNV component localized angiographically. In the verteporfin group, the absolute scotoma grew from 2.5 mm(2) at baseline to a final size of 7.3 mm(2) at month 24. In the placebo group, the mean lesion size of the absolute scotoma enlarged from an initial size of 2.7 mm(2) to 31.5 mm(2) after 24 months. The relative scotoma increased from 7.9 mm(2) at baseline to 20.8 mm(2) at month 24 in the verteporfin group, whereas a progression from 8.5 mm(2) initially to 48.3 mm(2) at the final presentation was measured in the placebo group. Statistical analysis showed that both the mean absolute and relative scotoma sizes were significantly smaller in the verteporfin group than the placebo group for all intervals from 6 to 24 months (P<0.001). CONCLUSIONS: Documentation of macular function with SLO perimetry demonstrated a significant benefit of verteporfin therapy for the preservation of the central visual field. Absolute and relative scotoma sizes remained smaller after therapy. This may influence reading ability and visual rehabilitation.

Choroidal Neovascularization↗

PubMed1999

Functional improvement after phacoemulsification cataract surgery.

PURPOSE: To evaluate subjective functional visual improvement after phacoemulsification and intraocular lens (IOL) implantation and identify patient characteristics and treatment features associated with no functional improvement. SETTING: Academic referral practice, Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA. METHODS: A retrospective review was performed of the surgical results in 106 consecutive eyes of 102 patients who completed the American Society of Cataract and Refractive Surgery (ASCRS) Cataract Data Collection Form preoperatively and 1 month postoperatively. One surgeon performed all the surgery. The relationship of patient characteristics and treatment features and reported visual function was analyzed using an analysis of variance and the Wilcoxon rank sum and Fisher exact tests. RESULTS: One month postoperatively, all patients demonstrated improved visual acuity. However, 15 patients (14%) reported unimproved or decreased visual function. No statistically significant intergroup difference (P > .05) was detected in mean preoperative, postoperative, and fellow eye best spectacle-corrected visual acuities or refractive errors; reported severity of preoperative symptoms or satisfaction with vision; reported preoperative daily activity functioning or prevalence of hypertension and diabetes; type of anesthesia, lens material, or wound closure used; intraoperative or postoperative complication rates. However, patients reporting unimproved vision tended to be older and less satisfied with their quality of life and medical care than those reporting improved vision (P = .02, .03, .01, respectively). CONCLUSIONS: Self-reported visual function generally improved after phacoemulsification and IOL implantation; however, some older patients less satisfied with their quality of life and medical care reported no functional improvement despite improved visual acuity. These patients might benefit from an extended preoperative discussion of postoperative expectations.

Activities of Daily Living↗

PubMed1999

Impaired saccadic eye movement in diabetic patients: the relationship with visual pathways function.

The aim of this study was to evaluate whether a correlation existed between saccadic eye movements and visual pathways function in diabetic patients. Saccadic or fast Eye Movement System (EMS) and Visual Evoked Potentials (VEPs) were assessed in 20 insulin-dependent diabetic mellitus (IDDM) patients without long-term complications and in stable metabolic control and in 21 age-matched control subjects. In IDDM patients we observed significantly (p<0.01) longer EMS latency, while EMS velocity and accuracy were similar to those of controls; VEPs showed a significant delay in N75, P100, N145 latencies and significant reduction of N75-P100 and P100-N145 amplitudes. In IDDM patients no relationships between EMS and VEP parameters were found. In conclusion, EMS latency delay suggests an impairment of the saccadic eye movement system, while impaired VEPs may be ascribed to a dysfunction of the visual pathways. The lack of correlation between VEPs impairment and EMS latency delay suggests that in our IDDM patients the delay of saccadic latency cannot be exclusively related to a visual pathways dysfunction and could be ascribed to a diffuse neuronal involvement.

Adult↗

PubMed2005

VIS-O-BAC: exploratory visualization of functional genome studies from bacteria.

UNLABELLED: The visualization-aided exploration of complex datasets will allow the research community to formulate novel functional hypotheses leading to a better understanding of biological processes at all levels. Therefore, we have developed a web resource termed VIS-O-BAC designed for the functional investigation of expression data for model systems, such as bacterial pathogens based on a graphical display. Genome-scale datasets derived from typical 'omic' approaches can directly be explored with respect to three biologically relevant aspects, the genome structure (operon organization), the organization of genes in pathways (KEGG) and the gene function with Gene Ontology (GO) terms. The integrated viewers can be used in parallel and combine expression data and functional annotations from different external data repositories. The graphical visualizations evidently accelerate both the validation of regulatory information and the detection of affected biological processes. AVAILABILITY: http://leger2.gbf.de/cgi-bin/vis-o-bac.pl. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Chromosome Mapping↗

PubMed1989

[Taufon and emoksipin in the combined treatment of sclerotic macular dystrophies].

The paper analyses results after complex treatment of 105 patients with sclerotic macular dystrophies. Taufon was added for treatment of early sclerotic macular dystrophies in 37 patients, emoxipine--of exudative sclerotic macular dystrophies in 23 patients. The treatment resulted in a more pronounced rise of visual functions, and stabilization of the dystrophic process in the retina ensued in earlier terms as compared with results achieved in 45 patients treated by traditional methods. Remote results of the treatment, followed up for two years in 70 patients, have shown that the usage of taufon and emoxipine allowed to achieve stabilization of visual functions in 76% of patients, while traditional methods of treatment stabilized visual functions in 61.6%. Differential prescription of the above preparations allowed to achieve the rise of visual functions and a more complete stabilization of the dystrophic process.

Aged↗

PubMed1984

Factors affecting visual loss in benign intracranial hypertension.

Visual function and optic disc appearances were studied in 68 patients conforming to established criteria of benign intracranial hypertension (BIH). The clinical, radiological, and laboratory findings of those patients whose visual field or acuity deteriorated were compared with those who did not deteriorate over an average follow-up of 4.1 years. Definite loss of visual function occurred in 49% of eyes and was severe in 6%. Patients with high grade or atrophic papilledema, or peripapillary subretinal hemorrhage, were significantly more likely to have had deterioration of visual function. Transient obscurations of vision and the presence of optico-ciliary shunts were associated with severe visual loss. Anemia, older age, and high myopia were other risk factors for visual loss. Chronic papilledema may cause progressive visual loss and, for this reason, BIH is not a benign condition; fundal changes and visual function should be carefully monitored.

Adolescent↗

PubMed1994

Patterns of visual impairment associated with lesions of the preterm infant brain.

The visual function of 42 children with haemorrhagic and/or ischaemic cerebral lesions acquired before a gestational age of 35 weeks was examined and related to cranial ultrasound in the neonatal period and to MRI and neurodevelopmental status at follow-up. All 37 children with abnormal ultrasound scans and one of the five with normal ultrasound scans showed impairment of one or more aspects of visual function. While impaired acuity was more frequent among infants with MRI evidence of visual pathway damage, this was not an invariable finding. Normal or near-normal visual acuity did not preclude the presence of other functional visual deficits. The authors conclude that preterm cerebral insults may produce a variety of visual difficulties, the pattern and severity of which cannot be predicted on imaging. Each child therefore requires individual assessment of multiple aspects of visual function.

Brain↗

PubMed1997

A comprehensive assessment of visual impairment in a population of older Americans. The SEE Study. Salisbury Eye Evaluation Project.

PURPOSE: The Salisbury Eye Evaluation Project is a longitudinal study of risk factors for age-related eye diseases and the impact of eye disease and visual impairment on physical disability. In this article, the authors report the prevalence of visual impairment in their population and explore the relations among the various measures of visual function. METHODS: A population-based sample of 2520 residents of Salisbury, Maryland, between the ages of 65 and 84 years were enrolled in the study. Twenty-six percent of participants were black. Vision tests included best-corrected Early Treatment Diabetic Retinopathy Study acuity, Pelli-Robson contrast sensitivity with and without glare, Randot stereoacuity, and 60 degrees Humphrey visual fields. RESULTS: Visual function decreased linearly with age for the acuity, contrast sensitivity, glare, and visual field tests. Stereoacuity remained constant into the mid-70s and declined at an accelerating rate thereafter. Black participants had lower contrast sensitivity, reduced stereoacuity, and worse visual fields, at all ages compared to white participants; however, white participants were more sensitive to glare. The overall prevalence of visual acuity impairment in blacks was 5.6% versus 3.0% for whites, using the traditional United States definition (worse than 20/40 to better than 20/200) and 3.3% for blacks versus 1.6% for whites, using the World Health Organization definition (worse than 20/60 to 20/400). Acuity was correlated moderately with contrast sensitivity, stereoacuity, and visual fields (Spearman rho = 0.50, 0.35, and 0.34, respectively). The correlation between acuity and glare sensitivity was low (rho = 0.12). CONCLUSIONS: Many aspects of visual function, not just acuity, decline with age. Black participants have more visual impairement than do white participants for all tests except glare sensitivity. The prevalence of visual acuity impairement in the Salisbury Eye Evaluation population is lower than that reported by other studies using similar test procedures. Low-to-moderate correlations among vision test scores suggest that several different dimensions of visual function are being assessed.

Aged↗

PubMed2004

Reduced vision in older adults with age related macular degeneration interferes with ability to care for self and impairs role as carer.

AIM: To study the relation between visual impairment and ability to care for oneself or a dependant in older people with age related macular degeneration (AMD). METHOD: Cross sectional study of older people with visual impairment due to AMD in a specialised retinal service clinic. 199 subjects who underwent visual function assessment (fully corrected distance and near acuity and contrast sensitivity in both eyes), followed by completion of a package of questionnaires dealing with general health status (SF36), visual functioning (Daily Living Tasks Dependent on Vision, DLTV) and ability to care for self or provide care to others. The outcome measure was self reported ability to care for self and others. Three levels of self reported ability to care were identified--inability to care for self (level 1), ability to care for self but not others (level 2), and ability to care for self and others (level 3). RESULTS: People who reported good general health status and visual functioning (that is, had high scores on SF36 and DLTV) were more likely to state that they were able to care for self and others. Similarly people with good vision in the better seeing eye were more likely to report ability to care for self and others. People with a distance visual acuity (DVA) worse than 0.4 logMAR (Snellen 6/15) had less than 50% probability of assigning themselves to care level 3 and those with DVA worse than 1.0 logMAR (Snellen 6/60) had a probability of greater than 50% or for assigning themselves to care level 1. Regression analyses with level of care as the dependent variable and demographic factors, DLTV subscales, and SF36 dimensions as the explanatory variables confirmed that the DLTV subscale 1 was the most important variable in the transition from care level 3 to care level 2. The regression analyses also confirmed that the DLTV subscale 2 was the most important in the transition from care level 3 to care level 1. CONCLUSIONS: Ability to care for self and dependants has a strong relation with self reported visual functioning and quality of life and is adversely influenced by visual impairment. The acuity at which the balance of probability shifts in the direction of diminished ability to care for self or others is lower than the level set by social care agencies for provision of support. These findings have implications for those involved with visual rehabilitation and for studies of the cost effectiveness of interventions in AMD.

Activities of Daily Living↗

PubMed1985

Spatial contrast sensitivity in patients with multiple sclerosis.

Contrast sensitivity tests a basic visual function which is not examined by conventional visual acuity testing or visual evoked responses. It is frequently abnormal in patients with multiple sclerosis. The lack of relationship between VERs and SCSF implies that contrast sensitivity measures aspects of the visual system not examined by the conventional electrophysiological technique, probably visual function situated beyond the anterior visual pathway. It is therefore a useful complementary diagnostic test for patients with multiple sclerosis. Both VER and spatial contrast sensitivity separately detect a high proportion of patients with multiple sclerosis. When used in combination, the two techniques give a yield which approaches 100%. Contrast sensitivity testing as used here is cumbersome and time-consuming. Use of fewer spatial frequencies and/or adaptation of VER techniques for estimation of a contrast threshold may be more applicable for clinical use.

Adult↗

PubMed2004

[Impact of cataract surgery upon functional capacity of the elderly].

PURPOSE: To determine the impact of cataract intervention on visual function of the elderly and on autonomy in daily activities, analyzing the influence of clinical and sociodemographic variables. METHODS: Observational and longitudinal study. 185 elderly patients having undergone cataract surgery were compared with 179 elderly patients on a surgical waiting list. The first group was evaluated prior to surgery and at 4 months post-intervention. Control group patients were evaluated at the same times, without having received surgery. For all subjects, the state of visual function was determined by the Activities of Daily Vision Scale (ADVS). Degree of dependence in carrying out basic daily activities, cognitive state and self-perception of vision were also measured. Other variables were visual acuity, other ocular diseases and sociodemographic characteristics. RESULTS: Amongst the elderly patients having undergone surgery, the proportion of subjects able to carry out basic activities 4 months post-intervention (60.7%) was very similar to the initial pre-intervention figure (62.2%). However, in the control group, the proportion (63.1%) diminished significantly at the 4-month mark (48.8%) (p= 0.0001). Of the intervened subjects, 75.7% demonstrated improved self-perception of vision after 4 months as opposed to 15.4% of the non-intervened patients (p= 0.00001). Post-intervention, the mean score on the ADVS rose from 51.0 S.D. 28.4 to 76.0 S.D. 25.4 (p < 0.001). In contrast, the control group's mean score dropped from 54.8 S.D. 24.8 to 46.5 S.D. 27.1 (p < 0.001). CONCLUSIONS: Cataract surgery in the elderly improves visual function and prevents loss of autonomy, delaying dependency in carrying out basic daily activities.

Activities of Daily Living↗

PubMed1997

Contralateral and ipsilateral microsurgical approaches to carotid-ophthalmic aneurysms.

OBJECTIVE: The vicinity of carotid-ophthalmic aneurysms to the roof of the cavernous sinus, to the anterior clinoid process, and to the optic nerve or the optic chiasm requires well-defined surgical techniques. Although microsurgical techniques with ipsilateral direct approaches to these aneurysms have been described in detail, studies about contralateral strategies for the microsurgical treatment of carotid-ophthalmic aneurysms are rare and are mainly confined to case reports. The aim of this study is to describe how to decide on the ipsilateral and contralateral microsurgical approaches to such aneurysms and to demonstrate the surgical techniques for the ipsilateral and contralateral exposure of carotid-ophthalmic aneurysms. METHODS: In a series of 51 patients with 58 aneurysms of the ophthalmic segment of the internal carotid artery, nine patients with 10 aneurysms (4 large aneurysms, 6 small aneurysms) were treated via a contralateral microsurgical approach after careful preoperative planning. Preoperative planning was based on the analysis of clinical and radiographic data, including cranial computed tomography, magnetic resonance imaging, magnetic resonance angiography, and conventional cerebral angiography. RESULTS: The postoperative results were good in 38 (75%) of the patients, fair in 2 (4%), and poor in 3 (6%); 8 (15%) of the patients died after surgery. The postoperative follow-up was 4 months to 10 years. Postoperatively, 15 of 19 patients with uni- or bilateral visual deficits or visual field defects improved, 3 of the 19 patients experienced postoperative impairment of visual function, and 1 of the 19 patients had an unchanged visual field deficit. Visual impairment or unchanged visual function was observed in patients who underwent ipsilateral approaches, which was possibly caused by inappropriate intraoperative retraction of the optic nerve or chiasm. In all patients presenting with preoperative visual deficits who were treated via contralateral approaches, visual function improved in the postoperative course. CONCLUSION: Giant carotid-ophthalmic aneurysms that are eligible for surgical treatment as well as small and large aneurysms dislocating the optic nerve or the chiasm superomedially or medially should be approached via ipsilateral craniotomies. It is recommended that small and large aneurysms of the carotid-ophthalmic segment originating medially, superomedially, or superiorly, displacing the optic nerve or the chiasm superiorly, superolaterally, or laterally, be approached via contralateral craniotomies.

Adult↗

PubMed1997

Association of retinal capillary perfusion with visual status during chronic glaucoma therapy.

PURPOSE: The purpose of the study is to determine whether retinal microcirculation is associated with the degree of visual function in glaucomatous eyes receiving chronic bilateral medical therapy with topical beta-blockers. METHODS: A nonrandomized, 3-year prospective clinical study was undertaken on 37 patients with glaucoma and normal visual acuity receiving symmetric topical medication in both eyes. Humphrey 30-2, Henson CFA 2000, and Vistech 3 and 6 cycles/degree contrast sensitivity were obtained bilaterally at multiple visits, along with Oculix 1000 blue-field estimates of perimacular leukocyte velocity. The mean asymmetry of measurements obtained throughout the treatment period for each pair of eyes was determined, and correlations were obtained to assess visual function asymmetry circulatory asymmetry. RESULTS: Significant associations were observed between blue-field entoptic capillary leukocyte velocity measurements and those for all three visual function testing methods, the eye with the superior vision typically having the higher mean leukocyte velocity (P < 0.001 for both Humphrey mean deviation and Henson perimetry, P < 0.002 for Humphrey corrected pattern standard deviation, and P < 0.02 for contrast sensitivity at both 3 and 6 cycles/degree). CONCLUSIONS: Central retinal microcirculation is associated with various measures of central and peripheral visual function in glaucomatous eyes receiving beta-adrenergic blocker therapy.

Administration, Topical↗

PubMed1993

Progressive and static nonarteritic ischemic optic neuropathy treated by optic nerve sheath decompression.

PURPOSE: Optic nerve sheath fenestration has been advocated as an effective treatment for progressive nonarteritic ischemic optic neuropathy (NAION) and anecdotally effective for selected patients with NAION who have not had progressive visual loss. To determine whether optic nerve sheath decompression is of any benefit in patients with NAION, the authors reviewed their experience, surgically treating 23 patients with progressive NAION and 15 patients with static or nonprogressive NAION. RESULTS: Patients with progressive NAION had a significant improvement in visual function as measured by Snellen visual acuity after optic nerve sheath decompression (P = 0.0005). There was no statistically significant improvement in visual field mean deviation (P = 0.11). The 15 patients undergoing optic nerve sheath decompression for static NAION failed to demonstrate significant improvement in either visual acuity (P = 0.90) or visual field mean deviation (P = 0.87). Preoperative standardized echography was used to measure the optic nerve sheath diameter and ascertain its compressibility (30 degrees test). There was a significant difference in compressibility between eyes with static NAION and eyes with progressive NAION (P = 0.001). Accumulation of optic nerve sheath fluid was documented in three eyes initially presenting with NAION and then with development of progressive visual dysfunction. CONCLUSION: Optic nerve sheath decompression improves visual acuity but has little effect on overall visual function in patients with progressive NAION. Optic nerve sheath decompression does not improve visual field or acuity in patients with static NAION. Detection of significant intrasheath fluid by standardized echography helps to objectively differentiate patients with NAION who may benefit from optic nerve sheath decompression.

Adult↗