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At least 505 records · Page 28Linked to original sources
PubMed2006

[Is it possible to compensate for visual field defects?].

Is it possible for a driver to compensate for visual field defects by skill along with eye and head movements? Monocular field defects with a normal second eye are no problem, because a normal binocular visual field is adequate for all areas of traffic. A total bitemporal hemianopia creates a special situation, because the patient loses a three-dimensional space behind a vertical line through the point of fixation. He may have no binocular visual field. In this case the ability to participate in certain traffic situations may be limited with reduced risk profile. A real problem is posed by defects in the binocular visual field, e.g., due to lesions of the suprachiasmal visual pathway or due to ocular diseases causing damage to both eyes (e.g., glaucoma, diabetic retinopathy, etc.). Such defects usually cannot be compensated for, neither by skill nor by eye or head movements. Saccadic eye movement training and other procedures are only of limited help. These procedures may provide some compensation for daily use; a complete restoration of the ability to participate in traffic is not possible. Rare exceptions may be patients with damage to the visual pathway acquired peri- or postnatally or in early childhood when there is still enough plasticity in the visual system to develop mechanisms of compensation by completely changing the system of eye and head movements.

Automobile Driving↗
PubMed2006

[Optical quality after refractive corneal surgery].

Correction of myopia, hyperopia and astigmatism within its indicated margin by means of refractive corneal surgical procedures such as LASIK and surface ablation (e.g. PRK) is one of the standard procedures in ophthalmology. Now that advances in the fields of surgical techniques and the technical devices employed have further progressed in terms of safety and predictability, research also focuses on optical quality. "Optical quality" is not a clearly defined parameter, but can be captured indirectly by means of directly measured data. One has to start with the anatomical properties of the eye, which determine the optical images on the retinal level. The quality of the retinal image influences the eye's function, i.e. acuity and contrast perception. Finally, there is the subjective perception of the image we receive. "Optical quality" as such is reflected by the patient's evaluation of this image perception. Three phenomena are especially responsible for deterioration of the quality of the retinal image: diffraction, aberrations and dispersion. Some of the methods for measuring optical quality are subjective questionnaires, functional testing procedures for measuring visual acuity and contrast sensitivity, optical measuring procedures for the determination of optical quality, as well as biomicroscopy, aberrometry and corneal topography for assessing anatomical changes.

Cornea↗
PubMed2007

[Comparison of ILM peeling with and without the use of indocyanine green. Functional results for idiopathic macular hole after pars plana vitrectomy].

BACKGROUND: Pars plana vitrectomy with internal limiting membrane (ILM) peeling is the best known therapy for idiopathic macular holes. Indocyanine green (ICG) is useful for staining the ILM, although there is a dose related toxic effect on the inner retinal layers. We compared outcome results with and without the use of ICG. METHOD: Data from 61 patients with idiopathic macular holes, who underwent macular hole surgery were analyzed retrospectively. ICG was used on 36 eyes while for 25 eyes it was not used. After calculating logMAR, differences in visual acuity between both groups were analyzed for significance using the Mann-Whitney-U-Test. RESULTS: The logMAR for the entire group was 0.71+/-0.30 (20/100) preoperatively, after 1 month 0.71+/-0.36 (20/100), after 3 months 0.57+/-0.26 (20/80), after 6 months 0.54+/-0.38 (20/66) and after 12 months 0.36+/-0.32 (20/50). There were no significant differences between groups. CONCLUSION: There seem to be no significant differences in the development of visual acuity and the occlusion rate between patients treated with or without the use of ICG.

Aged↗
PubMed2006

[Diagnostics of metamorphopsia in retinal diseases of different origins].

We investigated the ability of preferential hyperacuity perimeter (PHP) and Amsler grid testing to detect metamorphosia in patients with macular hole (MH), central serous retinopathy (CSR), epiretinal membranes (EM), intermediate AMD (iAMD), classic and occult choroidal neovascularization (CNV) due to AMD, and compared the results. A total of 147 patients (n =153 eyes) with classic (35 eyes) and occult (38 eyes) CNV, iAMD (13 eyes), MF (23 eyes), RCS (11 eyes), EM (13 eyes) and control group (20 eyes) were involved. All of these patients underwent corrected visual acuity and eye examinations inclusive of the Amsler grid. The PHP test was performed after pupil dilation. In all patients, fundus photography and optical coherence tomography (OCT) (Humphrey/Zeiss OCT III) were performed. In patients with CNV and CSR a fluorescein angiography was also performed. Metamorphopsia detection rates by Amsler grid and PHP were compared statistically. The sensitivity of PHP vs Amsler grid in detecting metamorphosia was 69% vs 85% in patients with MH, for CSR 64% vs 73%, EM 77% vs 100%, iAMD 85% vs 100%, classic CNV 83% vs 94% and occult CNV 81% vs 71%. The results for patients with occult CNV were significant (P =0.046), using the chi(2)-test. The PHP-test showed high sensitivity for diagnosing CNV. In occult CNV, PHP was superior to the Amsler grid in detecting metamorphopsia. In the other diseases involving the macular (MH, EM, CSR, iAMD), the detection rate and sensitivity of the Amsler grid was superior to PHP.

Adult↗
PubMed1998

[Reduced visual capacity increases the risk of accidents in street traffic].

BACKGROUND: This study was carried out to investigate the relationship between the frequency of traffic accidents and impaired vision. MATERIALS AND METHODS: Seven hundred and fifty-four drivers involved in accidents were recruited, in addition to 250 accident-free drivers similar in age and driving experience as an control group. The age distribution of the persons involved in traffic accidents (mean 56.3 years) was similar to that of the control group (mean 57.7 years), the difference was not statistically significant. Both groups underwent a complete ophthalmological examination. RESULTS: All three types of accidents (night-time accidents, violations of right of way, accidents during an overtaking manoeuvre) had a statistically significantly higher incidence of reduced photopic visual acuity, mesopic vision and an increased sensitivity to glare. Some other visual functions were also abnormal, with differences according to the type of accident. In particular, there were noticeable differences between the control group and those who were involved in night-time accidents regarding mesopic vision and sensitivity to glare. Concerning mesopic vision, 15% of the 261 persons involved in night-time accidents did not reach the contrast limit of 1:5; with glare, 20.7% failed. In comparison 4% of the control group reached this critical limit without glare and 7.6% with glare. These differences are highly statistically significant. In contrast to these findings, many of the drivers involved in accidents assessed their own visual capability as "excellent". CONCLUSIONS: The results of this study show that reduced mesopic vision and increased sensitivity to glare are accompanied by an increased risk of night-time accidents (for example, collisions with a non-illuminated obstacle). This emphasizes the importance of regular ophthalmological check-ups including visual functions such as mesopic vision and sensitivity to glare, which currently are not required by the traffic laws in Germany.

Accidents, Traffic↗
PubMed2001

Asymptomatic visual loss in multiple sclerosis.

Visual disturbances are common in multiple sclerosis (MS) and often a result of acute demyelinating optic neuropathy. Careful examination of MS patients, who have never suffered optic neuritis, may also reveal asymptomatic visual loss. This type of silent disease activity was investigated by computerised resolution perimetry, which has the potential to reflect the percentage of functional retino-cortical neural channels. The time of onset and the evolution of asymptomatic visual loss was investigated. One approach was to retrospectively select patients who never had suffered acute optic neuritis from a closely monitored MS population and re-examine them again. Sixteen patients were identified and vision was evaluated during a period of 5.5-9 years of follow-up and compared with that in 14 healthy controls. The mean channel percentage of the MS group was 89 +/- 19 % (SD) on entry into the study, compared with 110 +/- 15% (SD) of controls (p < 0.003). At termination of the study the mean percentage was essentially unchanged both in MS patients (87 +/- 21%, SD) and controls (110 +/- 19%, SD). The second approach was to test a group of 7 patients with MS or strongly suspected MS, with the same method, in close connection with their first clinical exacerbation. All cases lacked visual symptoms and none had previously had acute visual loss. Again, virtually all performed subnormally in the vision tests, and to the same degree as in the first group of patients. Results were compared with those obtained from 25 MS patients who had experienced one or more attacks of optic neuritis. Compared with controls the loss of functional retino-cortical neural channels was 20% in patients without a previous history of optic neuritis and 30 % in patients who previously had experienced optic neuritis. We conclude that asymptomatic visual loss seems to be a universal feature of MS and has a substantial impact on the visual pathways, that it is present already at the time of clinical onset of the disease, and that any progression thereafter is slow enough to elude detection during several years of follow-up.

Adult↗
PubMed2003

Sine Amsler Charts: a new method for the follow-up of metamorphopsia in patients undergoing macular pucker surgery.

PURPOSE: To evaluate our new method for the follow-up of metamorphopsia in patients with a macular pucker. METHODS: Sine Amsler Charts (SAC) are a set of eight modified Amsler charts where we have replaced the straight lines by sine curves of the same frequency but with different amplitudes (grades I-VIII). The patient first examines a regular Amsler chart with the affected eye; subsequently the SAC are presented in random order to the fellow eye. With this eye the patient then selects the SAC with the amplitude that best corresponds to the metamorphopsia observed with the affected eye. After 30 min the test was repeated. A comparison of pre- and postoperative SAC scores was made in 63 patients. The correlations between preoperative visual acuity, membrane type, leakage on fluorescein angiography, preoperative SAC score, postoperative SAC score and postoperative visual acuity were analyzed. RESULTS: Preoperative repeat testing with the SAC revealed 100% reproducibility in the grading of metamorphopsia. Postoperative SAC was unchanged in 16% of cases, one grade lower in 54%, two grades lower in 21% and more than two grades lower in 7%. Postoperative visual acuity was unchanged (i.e., within two EDTRS lines of the preoperative value) in 49% of cases, improved in 48% and decreased in 3%. A decrease in SAC score with a two-line increase in visual acuity occurred in 43% of cases. CONCLUSION: The SAC examination is a reproducible and rapid method for the comparison of the preoperative and postoperative metamorphopsia in patients undergoing pucker surgery and it may serve as an additional outcome measure.

Aged↗
PubMed2004

Integrated visual fields: a new approach to measuring the binocular field of view and visual disability.

BACKGROUND: We have developed a method of quantifying the central binocular visual field by merging results from monocular fields (Integrated visual field). This study aims to compare the new measure with the binocular Esterman visual field test in identifying patients with self-reported visual disability. METHODS: Forty-eight patients with glaucoma each recorded Humphrey 24-2 fields for both eyes and an Esterman on the same day, and each completed a binary forced-choice questionnaire relating to perceived visual disability. Computer software merged sensitivity values from monocular fields to generate an integrated visual field and a related score of the number of defects at the <10 dB and <20 dB level. Receiver operating characteristic (ROC) analysis was used to compare the integrated visual field score and the Esterman disability score with individual responses to the questions on perceived difficulty with visual tasks. RESULTS: Comparison of areas under ROC curves revealed that a score based on the integrated visual field was generally better (median area: 0.79) than Esterman scores (median area: 0.70) in classifying patients with or without a self-reported perceived difficulty with visual tasks. CONCLUSIONS: The integrated visual field offers a rapid assessment of a glaucoma patient's binocular visual field without extra perimetric testing. As compared to an actual binocular field test (Esterman), the integrated visual field provides a better prediction of a glaucoma patient's perceived inability to perform certain visual tasks.

Adult↗
PubMed2004

Visual improvement during psychophysical training in an adult amblyopic eye following visual loss in the contralateral eye.

BACKGROUND: Recent publications have demonstrated neural plasticity in adult amblyopes subjected to psychophysical training based on perceptual learning. The purpose of this case report is to present rarely available prospective data of visual acuity development in a strabismic amblyope undergoing psychophysical training and pleoptic treatment after loss of function of the non-amblyopic eye. METHODS: The design is a prospective, observational and interventional case report. Visual acuity was tested monthly, with constant optical correction. The 60-year-old female patient participated in a psychophysical training implemented in our laboratory, and in pleoptic treatment. RESULTS: Slow functional improvement of the amblyopic eye was observed during a period of 10 months, both in the tests used for training and in visual acuity: single optotypes increased by 4 chart lines, crowded optotypes by 2-3 lines. CONCLUSIONS: To our knowledge, this is the first report of the new approach of perceptual learning in an adult amblyope after loss of vision in the contralateral eye. Our results represent further evidence that the visual system of adult amblyopes preserves a certain degree of neural plasticity, whether spontaneous or enhanced by training. Furthermore, that plasticity in adults is limited, and early diagnosis and treatment of amblyopia must remain the primary goal.

Amblyopia↗
PubMed2005

Short-wavelength automated perimetry in patients with migraine.

BACKGROUND: The aim was to investigate short-wavelength sensitivity deficits in patients with migraine. METHODS: Fifteen migraine and 18 age-matched healthy volunteers with normal ophthalmologic examination participated in this study. Migraine characteristics were graded by the Migraine Disability Assessment Questionnaire (MIDAS). All participants underwent SWAP (short wavelength amplitude perimetry) testing using a Humphrey field analyzer; there was a 30-2 presentation pattern. RESULTS: Short wavelength amplitude perimetry parameters for mean deviation (MD; p<0.0001) and pattern standard deviation (PSD; p<0.0001) were significantly worse in the migraine group. In the migraine group 53.3%. of eyes had glaucoma hemi-field tests (GHT) outside normal limits and 10 of these had early glaucomatous visual field loss. Statistically significant correlations were found between frequency of migraine attacks and MD (p=0.02; r=0.56) and PSD (p=0.03; r=0.41) and also between the MIDAS score and MD (p=0.03; r=0.49) and PSD (p=0.04; r=0.51). In all migraine cases with early glaucomatous visual field defect a corresponding site of the head was predominantly involved in headache (p=0.03). CONCLUSION: Some patients with severe migraine have earlier defects on SWAP suggesting a common vascular insult of glaucoma and migraine, and all migraine cases with high MIDAS scores should be further evaluated for early glaucomatous visual field defects using SWAP.

Adult↗
PubMed2006

Horizontal and vertical micropsia following macula-off rhegmatogenous retinal-detachment surgical repair.

BACKGROUND: Dysmetropsia or distorted image size perception (smaller: micropsia; larger: macropsia) is known to occur after successful surgical re-attachment for macula-off rhegmatogenous retinal detachment. However, the vertical and horizontal components of size distortion have not been previously quantified separately. The purpose of this article is to describe horizontal and vertical dysmetropsia occurring in patients following pars plana vitrectomy and gas treatment (octafluoropropane, C(3)F(8) or sulfur hexafluoride, SF(6)) for macula-off rhegmatogenous retinal detachment. MATERIAL AND METHODS: Four patients (mean+/-SD, 59+/-8 years; three women and one man) who had had pars plana vitrectomy and gas treatment for macula-off rhegmatogenous retinal detachment 6-7 months earlier underwent ocular examination, best corrected visual acuity test, threshold horizontal and vertical dysmetropsia measurement using a computerised version of the New Aniseikonia Test, slit-lamp examination and optical coherence tomography of the macula. RESULTS: All patients had binocular visual complaints including difficulty judging distances or reading, rivalry or asthenopia. The logMAR visual acuity (mean+/-SD) in the operated eye was 0.52+/-0.199 and 0.02+/-0.171 in the unaffected eye. All patients perceived the image as smaller (micropsia) with the affected eye, with differences ranging from -9 to 0%. Four patients showed 3% or more size difference between horizontal and vertical meridians. CONCLUSIONS: Dysmetropsia does occur in symptomatic patients following successful surgical repair of macula-off rhegmatogenous retinal detachment by pars plana vitrectomy and gas treatment. The effect on image size is heterogenous across the retinal area affected.

Aged↗
PubMed1998

Age-related deterioration of motion perception and detection.

PURPOSE: The purpose of this study was to evaluate the effect of aging on motion detection and perception. METHODS: Forty-six subjects, ages 19-92 years, were asked to view a motion stimulus. Infrared oculography was used to objectively evaluate motion detection by documenting the presence of optokinetic nystagmus as the subjects viewed the stimulus. Subjective responses to motion perception were recorded using a computer joystick. RESULTS: Optokinetic nystagmus was clearly detectable in all 46 subjects. Motion detection and perception thresholds showed age-related deterioration. No relationship was found to gender or age-gender interaction. CONCLUSION: The results indicate motion detection and perception thresholds deteriorate with age. This may reflect a susceptibility to age-related degeneration in specific cortical areas responsible for motion perception as well as neurodegeneration in the retinogeniculate pathway.

Adult↗
PubMed1999

Information from false statements concerning visual acuity and visual field in cases of psychogenic visual impairment.

BACKGROUND: If visual acuity (VA) and/or visual field (VF) is claimed to be worse than in reality, it can be difficult to estimate the actual VA/VF. This paper describes a method of proving malingering and of estimating the actual VA by statistical evaluation of the subjective responses to discrete visual stimuli. METHODS: VA is measured by using a Landolt or Snellen optotype with four possible directions. There are n (> or = 16) questions at each acuity level. Each direction of the optotype occurs with the same frequency. The sequence is not predictable. In testing the VF, the stimulus is presented in an unpredictable sequence but with the same frequency at each of four distinct locations outside the claimed field at the horizontal and the vertical meridian. The field is divided into four quadrants defined by the 45 degrees-225 degrees and 135 degrees-315 degrees meridians. The candidate is requested to search for the light. The target quadrant of the first eye movement is recorded. At each VA level, the distribution function of the binomial formula allows estimation of the probability Pc of < or = kc and > or = kc correct answers to n questions by mere accident. Regarding the VF, the direction of the first saccade at each stimulus presentation can be processed accordingly. RESULTS: If n = 32 and kc = 0,1,2, the chance P that this pattern is merely accidental is about 0.0001, 0.001, 0.007. Values of P < or = 0.01 strongly suggest that the answers were voluntarily wrong. Preference for the opposite direction can also point to psychogenic influence: If ko = 15,16,17,18, P is about 0.006, 0.002, 0.0006, 0.0002. CONCLUSION: Systematically false statements can yield valuable information about the actual visual functions.

Adult↗
PubMed2005

Radial optic neurotomy in central retinal vein occlusion: preliminary results.

BACKGROUND: To investigate the efficacy of radial optic neurotomy (RON) on visual prognosis and clinical findings in central retinal vein occlusion (CRVO). METHODS: Prospective, non-randomised, self-controlled comparative trial. Six patients with ischemic CRVO who had visual acuity (VA) less than or equal to 0.1 and duration of CRVO at least 1 month, and 6 patients with non-ischemic CRVO who maintained their VA less than or equal to 0.1 during the minimal follow-up of 3 months underwent pars plana vitrectomy and RON. LogMAR VA measurement and fluorescein angiography were performed before and after surgery. Automated perimetry was obtained from 4 patients at the last visit. Main outcome measures were VA and clinical changes in fundus appearance of CRVO evaluated with fundus photography and fluorescein angiography. RESULTS: Radial optic neurotomy was successfully performed in all 12 patients without serious complications. All patients were of clinical improvement of fundus findings. In 11 (92%) patients, a visual improvement of at least 2 lines was observed. After mean follow-up of 9.3 months, mean improvement in VA was 5.1 +/- 3.1 lines (range, 2-14 lines). Cystoid macular oedema and degeneration were observed in 8 (67) patients. Four patients, two of whom had preoperative ocular hypertension had raised intraocular pressure controlled with topical antiglaucoma medication. In late postoperative period, one ischemic eye developed vitreous haemorrhage necessitating vitrectomy and endolaser photocoagulation. Automated perimetry revealed segmental visual field defects in all the examined eyes. CONCLUSIONS: Radial optic neurotomy in CRVO yields clinical and visual improvement in majority of the patients. Cystoid macular oedema and degeneration are the major factors responsible for restriction of VA improvement. Further randomised and controlled studies with longer follow-up are essential to establish the appropriate timing and indications of RON in CRVO.

Adult↗
PubMed2005

Visual disturbances and migraine.

There is a close relationship between headache and the visual system. Visual symptoms are prominent features of clinical syndromes such as migraine, cluster headache, and the trigeminal autonomic cephalgias. There are also strong links between headache and the visual system on the basis of genetics, molecular biology, neurophysiology, and neuroimaging. Studies of these links are leading to the development of novel therapies for a variety of headache syndromes. This review is designed to summarize the most recent literature on headache and the visual system. A particular emphasis is placed on publications of interest to clinicians.

Headache Disorders↗
PubMed1991

Effects on driving performance of visual field defects: a driving simulator study.

To elucidate the possible traffic safety risks induced by visual field defects, a method was developed based on a driving simulator. The capacity to detect stimuli of different sizes appearing in 24 different positions on the screen in front of the driver was measured. Two groups of normal subjects and a number of subjects with different visual field defects were studied. In the groups of normals, the median reaction times were fairly homogenous. There was a slight difference between central and peripheral stimuli, which was somewhat larger for the older subjects. Among the subjects with field defects, the individual variations were very dominant. Very few of these showed a capacity to compensate for their deficiency. In order to gain insight into possible compensatory mechanisms of these persons, eye movement recordings were made. The results indicate that the visual search pattern may be of importance in this respect. Some comparisons with respect to detection capacity were also made with one-eyed subjects and with optically generated field restrictions (spectacles and spectacle frames).

Adult↗