Biomedical subjects

M Gräf

Publications and source records attributed to M Gräf.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Vertical vergence in convergence].

PURPOSE: To report on a 7-year-old boy with a small left-over-right deviation (-VD) which increased when the head was tilted to the left shoulder and during convergence. METHODS: The squint angles were measured by the unilateral and alternate prism cover test at distance and near fixation when the head was in ortho-position and when it was tilted. RESULTS: At distance fixation (D) there was a latent deviation of-VD 3 degrees. With near fixation (N) at 0.3 m the vertical phoria increased to-VD 18 degrees. The angle of deviation was not influenced by (N) convex lenses in front of the fixating eye despite an adequate dis-accommodation. The-VD was fairly comittant in right and left gaze. At 45 degrees head tilt to the right shoulder the-VD decreased to (D) 2 degrees and (N) 12 degrees. At 45 degrees head tilt to the left shoulder the-VD increased to (D) 18 degrees and (N) 26 degrees. A dissociated vertical deviation was excluded by the dark red glass test and by the reversed fixation test. CONCLUSION: The disturbance can be explained by a, presumably congenital, supranuclear misinnervation and has to be differentiated from other types of vertical deviation.

Child↗

PubMed2000

[Congenital nystagmus: indication, results and dosage of Kestenbaum surgery in 34 patients].

BACKGROUND: Abnormal, nystagmus related head postures can be treated by Kestenbaum's procedure, if the concept of artificial divergence (Cüppers procedure) is not expected to work. In this retrospective study, we evaluated the effects of Kestenbaum surgery in order to establish dosage recommendations. PATIENTS AND METHODS: Solely patients who received Kestenbaum surgery (maximum 3 mm dosage difference between both eyes, i.e., without additional artificial divergence) for a horizontal head turn (HT) due to nystagmus were included in this study. Exclusion criteria were previous eye muscle surgery, strabismus, lacking binocular vision, and cerebral disease. The millimetres of surgery and the pre- and 3-6 months-postoperative findings (HT and visual acuity at 5 m distance, stereopsis) were evaluated. RESULTS: Of the 34 patients, 21 had a HT to the left side and 20 were male. The age at surgery (median, 10%- and 90%-quantile) was 7 years (4-32), the total amount of surgery 32 mm (20-40), and the preoperative HT 30 degrees (20-40). Postoperatively (n = 31), the HT amounted to 7 degrees (0-20). The reduction of HT was 67% (25-100), the efficacy of surgery 0.8 degree (0.3-1.0) per millimetre total amount of surgery on both eyes together. Four patients needed further surgery due to residual HT. Postoperatively, the maximum visual acuity was available without HT or with significantly less HT than preoperatively. Stereopsis showed a trend of improvement. CONCLUSIONS: The Kestenbaum procedure has a dose/effect ratio similar to that of recess/resect surgery for strabismus. Due to a long term efficacy of 1.5 degrees/mm, a dosage (in millimetres) on each eye of two thirds of the HT (in degrees) can be recommended. Physiological and methodical factors (false measurements) have to be discussed as an explanation for apparently low efficacy of surgery.

Adolescent↗

PubMed2000

Reduction of postoperative nausea and vomiting by dimenhydrinate suppositories after strabismus surgery in children.

UNLABELLED: Although dimenhydrinate has been used for treatment and prevention of postoperative nausea and vomiting (PONV) since the fifties, there have been few controlled studies about its efficacy. We performed a double-blinded study of 301 children aged 4 to 10 yr who underwent strabismus surgery. Preanesthetic medication with midazolam (0.5 mg/kg) as well as application of either dimenhydrinate suppositories or a placebo preparation was performed 30 min before the induction of anesthesia. Anesthesia was induced with thiopentone (5-10 mg/kg) and vecuronium (0.1 mg/kg) and maintained with halothane (1%-2%) in N(2)O/O(2) (65%/35%). The incidence of PONV, requirements for rescue dimenhydrinate, and time to recovery were recorded. The overall incidence of PONV was 60.1% in the placebo group and 30.7% in the dimenhydrinate group. In the dimenhydrinate group, children had to be observed in the recovery room significantly longer than those in the placebo group. Children having received dimenhydrinate were discharged from the recovery room with lower arousal scores. We conclude that the rectal administration of dimenhydrinate is effective for the prevention of PONV, although the sedative effect may require longer postoperative monitoring. IMPLICATIONS: We performed a double-blinded, randomized study to investigate the effects of prophylactic rectal dimenhydrinate application on postoperative nausea and vomiting in children undergoing strabismus surgery. In comparison with placebo, dimenhydrinate reduced the incidence of postoperative vomiting from 60.1% to 30.7%.

Anesthesia, Inhalation↗

PubMed1999

[Causes of blindness in Hessia in 1996].

BACKGROUND: Despite of medical progress, the incidence and prevalence of blindness are continuously increasing. In Hessia, the number of persons receiving blindness compensation payment increased from 8,346 in 1985 to 11,166 in 1996 by 2.6% per year. In 1996, the rate (prevalence) amounted to 1.85/1000 of the Hessian population. METHODS: In this study, the incidence of blindness (visual acuity < or = 0.02 or equivalent visual handicap) and substantial visual handicap (visual acuity < or = 0.05 or equivalent visual handicap) according to the Hessian law was investigated by means of the records of new candidates for blindness compensation payment whose applications were granted in 1996. The causes of blindness (main diagnosis), visual acuity, age, gender, and nationality were evaluated. RESULTS: The Hessian administration for public welfare had filed 2,609 alterations of applications concerning sundry social assistance. Out of these, 2,395 files (91.8%) were available, 1411 applications met the requirements for blindness compensation payment, 45.4% were graded substantially visually handicapped for the first time, 43.4% were graded blind for the first time, and 11.0% were graded blind after previous substantial visual handicap. In 0.2%, a further classification was not necessary. Applied to the Hessian population of 6.027 million people, the incidence of blindness was 0.14/1000. 67.9% were female, 30.9% were male, in 1.2% the gender was not evaluable. The age median of the candidates was 78 years (male: 74 years, female: 80 years), 84.3% of the candidates were > or = 60 years old. The most frequent causes of blindness (substantial visual handicap) were: age related macular degeneration 35.3% (49.5%), diabetic retinopathy 15.0% (17.0%), glaucoma 12.6% (7.8%), tapetoretinal degenerations 6.9% (1.7%), optic nerve atrophy 6.1% (4.3%), and myopia 5.0% (6.5%). CONCLUSION: Age related affections are the most frequent causes of blindness. Due to the increasing life expectancy and rather constant birth rates, a further increase of blindness rates has to be expected.

Adolescent↗

PubMed1999

[Determining visual acuity with LH symbols and Landolt rings].

PURPOSE: Lea (LH) symbols seem to be favourable for visual acuity assessment in childhood. The symbols of the LH test are well standardized and applicable to preschool children. We compared the visual acuity determined by LH single symbols (LH) and the acuity measured with the Landolt-C (LC). PATIENTS AND METHODS: 138 cooperative subjects aged 7 to 91 years were examined. Their visual acuity was either normal or reduced due to various etiologies. Their refractive error was corrected. The monocular LH and LC were determined by a 3/4 criterion (study 1). In 19 healthy subjects aged 21 to 58 years, acuity was reduced stepwise by 5 different calibrated occlusives (study 2). A Lighthouse single symbol book (LH symbols) was used at a distance of 3 m. LC was determined at a distance of 5 m. The luminance of the test field was 180-200 cd/m2. The right eye of each patient and the amblyopic eye of the squinting patients was taken for statistical evaluation. The strabismic patients' interocular differences of LC and LH were compared. RESULTS: Within study 1, LC ranged from 0.02 to 2.0 and LH from 0.03 to 2.5. LH overestimated LC by 1.4 lines on an average (t-test p < 0.0001). The regression equation lgLH = 0.95 lgLC + 0.11 describes a high correlation (r = 0.95) between LH and LC. The relations between LH and LC of 43 strabismic amblyopic patients and the remaining subjects did not significantly differ. Due to the criterion of an interocular LH-difference > 1 line, 85.7% resp. 90% of the strabismic amblyopic patients with an interocular LC difference > 1 resp > 2 lines were detected. In study 2, LC ranged from 0.1 to 1.6, LH from 0.12 to 2.0. The mean difference LH-LC was 1.3 lines. The regression equation was lgLH = 0.91 lgLC + 0.08 (r = 0.95). CONCLUSION: LH symbols allow a reliable measurement of recognition acuity. Due to the design of the symbols, they are excellently suitable for application to preschool children. Age related normal values should be established. The systematic difference between the LC acuity and the LH acuity measured with the Lighthouse LH single symbol book by 1.4 lines has to be considered.

Adolescent↗

PubMed1999

[Clinical application of a new method for the objective estimation of minimum visual acuity].

PURPOSE: Recently, a new method for the objective estimation of the minimum visual acuity (OEM) by means of suppression of the optokinetic nystagmus has been presented (Klin Monatsbl Augenheilkd 1998;212:196-202). This study reports on the clinical use of this method. METHODS: In 120 individuals referred to our clinic either to procure an ophthalmological expert opinion or for differential diagnosis of an unclear visual impairment, an OEM was performed. The result of the OEM was compared to the clinical findings (history, biomicroscopy of anterior and posterior segments, objective refractometry, pupillary responses, binocular alignment, motility, binocular vision, colour vision, applanation tonometry, electrophysiology, fluorescein angiography, neurologic, radiologic, psychiatric findings, reproducibility of visual acuity and visual field statements under different conditions, comparison of subjective and objective visual field data, statistical prove of false visual acuity and visual field statements) which were critically interpreted concerning the credibility of the subject's statements. RESULTS: As a result of the clinical examinations, the stated visual acuity of 62 individuals was credible. In one of these individuals, the OEM pointed to a slightly (1dB) better visual acuity. The statements of 7 individuals could not be categorized clinically. The OEM pointed to a better acuity in 3 cases. The stated vision of the remaining 51 individuals was not credible. In 38 of these cases, the OEM pointed to a better acuity, or false statements could be proven by the OEM. CONCLUSION: A significant rate (75%) of the individuals whose statements were not credible was detected by the computer-aided, nystagmographic method of OEM. The method allows an estimation of the actual minimum visual acuity and yields evidence of false statements concerning the detection acuity.

Biofeedback, Psychology↗

PubMed1998

Sensitivity of the MTI photoscreener for amblyogenic factors in infancy and early childhood.

BACKGROUND: Screening for amblyogenic factors in infancy by pediatricians is unsatisfactory, as they hardly ever detect ametropia or microstrabismus. As photoscreening seems to be a helpful method to detect even small squint angles and refractive errors, we tested the MTI photoscreener for its sensitivity with respect to amblyogenic factors. PATIENTS AND METHODS: One hundred and twelve children aged 6-48 months were first examined with the MTI photoscreener. Then each child underwent complete medical examination by an ophthalmologist and an orthoptist. The examination included the Hirschberg test (corneal reflex evaluation), the Brückner test (fundus red reflex), and, where possible, the Lang stereotest, the cover test and visual acuity assessment, as well as a motility test, biomicroscopy, ophthalmoscopy in mydriasis and refractometry in cycloplegia. Exclusion criteria were any organic pathological results, manifest strabismus, ametropia > or = 2 D and astigmatism > or = 1 D. An orthoptist, a pediatrician and two ophthalmologists independently evaluated the Polaroid pictures according to the criteria given in the handbook of the MTI photoscreener. RESULTS: For 10 children the evaluation with the MTI photoscreener was not possible despite the fact that photographs were retaken several times. Thirteen photographs showing obvious pathologic findings despite their poor quality were included. Eighty-three of the remaining 102 children failed the eye examination according to the above-mentioned criteria. The mean sensitivity of the MTI photoscreener was determined to be 82.8%. The ability to correctly identify the absence of any amblyogenic factors (specificity) was 61.8%. CONCLUSIONS: Sensitivity was high when compared to the usually low detection rate during pediatric examinations. Due to the low specificity, effectiveness was poor. Therefore an ophthalmological examination should be included in the preventive screening during infancy and early childhood.

Amblyopia↗

PubMed1998

[Objective assessment of minimum visual acuity by suppression of optokinetic nystagmus].

PURPOSE: To develop and to validate an objective method which allows an estimation of the visual acuity (VA) of adults. METHODS: A horizontal optokinetic nystagmus (OKN) was elicited by a vertical rectangular grating presented on a PC-screen and was recorded by an infrared reflection method. Superimposition of three stationary black detection stimuli was used to suppress the OKN. The size of these stimuli was increased every two seconds, in ten steps. Suppression of the OKN was taken as an indication that the stimuli were detected. The relation between the smallest effective stimulus and logVA was evaluated in 65 healthy volunteers (130 eyes) with artificially reduced VA and 425 cooperative patients (842 eyes) whose VA was reduced due to different etiologies. The tolerance intervals of logVA related to the discrete detection stimuli were calculated. RESULTS: The method allows an estimation of the least expectable VA in steps of 0.8, 0.32, 0.25, 0.12, 0.1, 0.06, 0.03 und 0.025 due to the smallest value of three trials. The least VA of strabismic amblyopic eyes can only be estimated in steps of 0.16, 0.06, and 0.02. A VA > 0.02 can be proven with high reliability. CONCLUSION: The method allows a clinically useful, objective estimation of the least VA without observer bias in non-amblyopic eyes.

Adolescent↗

PubMed1997

[Visual field examination in limited patient cooperation].

Objective methods to estimate the visual field are necessary, if a conventional subjective perimetry is impossible due to limited cooperation. Objective methods are indicated in infants, handicapped patients, patients with psychogenic visual field loss, and malingerers. An objective estimation of the visual field can be performed by means of pupillary light reflexes, voluntary and involuntary eye movements, and visual evoked potentials. Systematically false responses contain useful information regarding the proof of misrepresentations. The reproducibility of visual field defects can be checked by testing at different distances from the screen. This article reports on handy methods requiring no large-scale equipment.

Adult↗

PubMed1996

[Examinations with the Cardiff Acuity Test].

Recently, a new preferential looking (PL) test has been presented for measuring visual acuity in infants and young children (Cardiff Acuity Test, CAT). The PL target is a schematic vanishing picture composed of isoluminant lines with different spatial orientations. Fifty-three healthy children (4-34 months, group 1), 28 (4-35 months) children at risk for amblyopia due to strabismus (group 2), 19 healthy subjects, and 157 patients (group 3) were tested with the CAT. In group 2 the CAT was compared with the fixation preference test. In group 3 the CAT was compared with a recognition test (Landolt C test). In group 1 the interocular difference of the CAT data was a maximum of 1 dB (70% 0 dB, 30% 1 dB, 1/3 so-called octave). Thus, an interocular difference of > 1 dB was considered to be suggestive of monocular or asymmetrical visual impairment. The maximum value 6/6 was frequently achieved (RE 44%, LE 36%, > 18 months RE 57%, LE 46%). In group 2 only 20% of the monolateral strabismic children showed an interocular difference > 1 dB in the CAT. In group 3 we found significant correlations between the CAT and Landolt acuity. A ratio of about 1.7/1 between CAT and Landolt acuity remained constant in cataract eyes as compared to healthy eyes. In amblyopic eyes due to strabismus this ratio was 3.7/1. Thus, amblyopia was underestimated with the CAT. Without limiting the examination distance, interocular differences > 1 dB in the CAT occurred in 52% of the strabismic amblyopic patients (potential sensitivity). At a distance of 1 m this rate decreased to 22% (real sensitivity). In conclusion, the CAT definitely lacks sensitivity for strabismic amblyopia. The data suggest that the real sensitivity could be improved by using higher spatial frequencies. The use of familiar shapes instead of gratings such as PL targets affects cooperation favorably in 12- to 36-month-old children.

Amblyopia↗

PubMed1996

[Bilateral congenital mydriasis with accommodation failure].

In the literature congenital mydriasis is described as a very rare condition and explained as a result of isolated aplasia of the iris sphincter muscle. Aplasia of the ciliary muscle was assumed to cause congenital accommodation insufficiency. A case of congenital mydriasis with lack of accommodation is presented. The first ophthalmological check-up was 2 weeks after surgery for a persistent ductus arteriosus Botalli. The girl was 15 weeks old. Her parents had watched her dilated pupils since birth. The diameter of both pupils was 6.5 mm. They did not react to light, lid closure, or conjunctival administration of pilocarpine solutions up to 1%. A refractive error of OD +3.0 D and OS +2.5 D was measured by retinoscopy. The hypermetropia was also uninfluenced by topical locarpine 1%. Two drops of pheylephrine 2.5% caused additional pupillary dilatation of 0.5 mm. Besides the lack of accommodation and pupillary constriction, all ocular findings were regular. No chromosomal abnormalities were found. No further cases of pupillary disorders are known in the family. These findings can only result from the lack of cholinergic sensitivity or aplasia of the pupillary sphincter and ciliary muscle. The infant was supplied with bifocals and sunglasses. The near correction was spontaneous. At the age of 15 months there was a grating acuity of 20/80, which is in the normal range, as measured by preferential looking.

Accommodation, Ocular↗

PubMed1996

[Objective determination of visual acuity. Improvement of an infrared nystagmography method and comparison with pattern visual evoked potentials].

BACKGROUND: The purpose of this study was to optimize a new nystagmographical method of objective assessment of visual acuity and compare it to an electrophysiological method. METHODS: In the nystagmographical method motionless brake marks were superimposed on a moving grating pattern, causing suppression of optokinetic nystagmus (OKN). The smallest brake mark that interrupted the OKN was taken as an objective measure for visual acuity (VA). In the electrophysiological method rapid sequences of high-contrast checkerboard patterns of different spatial frequency were presented in a pattern on-off mode in a foveal field. The VEP response function was extrapolated to 0 microV. The objective values of 94 healthy eyes with artificially reduced vision (VA 0.05-2.0) and 314 eyes with pathological reduction of VA due to different etiologies were compared. RESULTS. The selectivity of the nystagmographical method could be improved. With the exception of strabismic amblyopia, the results were closely correlated with the VA. The least VA could be estimated in steps of 0.06, 0.1, 0.2, 0.5 and 0.8. CONCLUSIONS: The new nystagmographical method yields useful information about the least VA if strabismic amblyopia is excluded.

Adolescent↗

PubMed1995

[A new site-independent tonometer (ProTon) in comparison with the Goldmann applanation tonometer].

BACKGROUND: A new position-independent and portable Mackay-Marg-tonometer in miniature, the so-called ProTon (PT), was compared with reference to its clinical usefulness with the Goldmann applanation tonometer (GAT), being a commonly accepted reference. METHODS: The intraocular pressure (IOP) in 164 eyes of 85 adults (patients and volunteers without ocular disease) was measured using the sequence GAT, PT and again GAT--each three times in a row-by three different investigators in a randomized scheme. In an attempt to detect any systemic influence, the difference obtained by subtracting the value measured using PT from the value attained using GAT was compared to the central corneal thickness and radius. Moreover, the central IOP readings were compared with the peripheral IOP in 60 eyes of 30 volunteers measured by PT, to detect any possible influence of the locality of measurement. Dependence of measurement on individual influences was examined by comparing PT-values obtained by each investigator. RESULTS: Linear regression analysis between PT (y-axis) and GAT (x-axis) for an IOP range of 0 to 62 mm Hg resulted in the following equation: PT = 1.036 x GAT -2.00 with a PT value standard deviation of 1.65 mm Hg (r = 0.988; p < 0.0001). Reproducibility of each of the three PT-values (mean pair difference of 1.1 mm Hg) corresponded to the analogous first two GAT-values (differences 1.0 up to 1.2 mm Hg). The mean IOP-value of 1) the GAT measurements (1 to 3) was 18.35 mm Hg, 2) of the last three GAT measurements, 17.15 mm Hg and 3) of all PT-measurements, 16.40 mm Hg. No statistical difference was found between the IOP measured centrally and peripherally. A clinically nonsignificant dependency for PT-readings on the examiner was verified. CONCLUSION: Due to the high reproducibility, independency on examiner and acceptable correspondence of PT with GAT values, the PT appears to be a promising new development for use in measuring intraocular pressure. It will be necessary to modify the calibration of PT since IOP measured systematically about 2 mm Hg too low.

Adolescent↗

PubMed1995

[1H-NMR spectroscopic study of cysteamine eyedrops].

BACKGROUND: The efficiency of cysteamine eye drops in the treatment of cystinosis has been demonstrated in several studies: Corneal cystine crystals can be removed by topical cysteamine. Cysteamie 0.5% eye drops were superior to a 0.1% solution. It is not clear how fast cysteamine is oxidized to cystamine under the influence of atmospheric oxygen. MATERIAL AND METHODS: Samples of a new bottled cysteamine 0.5% solution were analysed 1H-NMR-spectroscopically over a period of several weeks (AM 400/WB-NMR-instrument, Bruker/Karlsruhe; 400.15 MHz). Samples bottled in an argon atmosphere were compared to samples bottled without inert gas. Definite samples were opened four times a day (A). The remainder of the samples was stored closed (B). RESULTS: In sample A a 1:1 weight ratio between cysteamine and cystamine was reached after 38 days. In samples B cysteamine was not oxidized to cystamine. The initial amount of cystamine was something lower in samples with argon, but argon could not prevent the decrease of the cysteamine concentration in sample A. CONCLUSIONS: The preparation of cysteamine solution in an argon atmosphere is useful. One bottle can be used for about one week, if less than 10% of the oxidation product cystamine is accepted.

Cornea↗

PubMed1995

[Photo- and videographic determination of the dilatation deficit in differential diagnosis of Horner syndrome].

Physiological anisocoria, a very frequent condition among normal subjects, must be differentiated from Horner's syndrome. Aside from a history including evaluation of older photographs, pharmacological pupil testing with cocaine eye drops has been the "gold standard". Measurement of dilation lag, occurring in Horner's syndrome, is much less common and normal values are missing. Therefore, we evaluated various photographic parameters for testing for the best parameter to discriminate Horner's syndrome (22 patients) from physiological anisocoria (16 patients). Additionally, we tested whether a commercially available camcorder is sufficient to record pupillary dilatation lag. An anisocoria of 0.6 mm or more 4s after switching off the illumination discriminates physiological anisocoria from Horner's syndrome with a sensitivity of 82% and a specificity of 69%. A dilatation speed of 1.1 mm/4 s shows the same ability to differentiate in anisocoria and does not provide any better results. Because of the good correlation between post-cocaine anisocoria and anisocoria after 4 s in darkness, photographic or videographic measurements of the pupillary dilatation lag may complete or in some cases even replace cocaine testing.

Adolescent↗

PubMed1995

[A new method for objective vision assessment using infrared nystagmography].

Objective assessment of visual acuity (VA) is necessary in cases of malingering or poor cooperation in subjective VA evaluation. Based on Ohm's idea of the suppression of experimentally evoked optokinetic nystagmus (OKN), a new objective visual acuity test is presented. A commercially available system for monitoring eye movement (OBER2) allows the test to be performed on a standard PC with a minimum amount of time. A grating pattern moving horizontally on the screen evokes OKN, which is recorded by infrared nystagmography. Superimposed black optotypes of increasing size (brake marks) suppress OKN as soon as they are recognized. Eighty-two normal eyes with VA artificially reduced by different Bangerter dispersion foils (VA 0.04-1.6) and 152 eyes with visual disturbances (VA 0.04-1.0) of various etiologies were examined. The test allowed estimation of the least VA in steps of > or = 1.0, > or = 0.25, > or = 0.1, > or = 0.05. None of the eyes examined had a VA below these values when the OKN was suppressed by the referring brake mark.

Electronystagmography↗

PubMed1995

[Photographic pupil diagnosis in Horner syndrome].

In cases of miosis without other clinical signs and not contributory medical history it is often hard to differentiate Horner's syndrome. In these cases the pharmacological testing with cocaine eye drops is a well established and validated method. The physiological testing, i.e. the detection and measurement of a dilatation lag in Horner's syndrome, is not so common. For this reason we measured the dilatation of pupils in 22 Horner's syndromes and 16 physiological anisocorias to find limit ("cut off") values. We used flash photography and a commercial available camcorder and took photos in bright light (400 cd/m2) as well as 4 and 15 seconds after cessation of light stimulus in darkness. An anisocoria after 4 seconds of darkness greater than 0.6 mm distinguishes both groups with a sensitivity of 82% and a specifity of 69%. A dilatation speed of the smaller pupil during the first 4 seconds of darkness lower than 1.1 mm/4 sec is also a good threshold value. Because of the additional good correlation of these parameters to the anisocoria after cocaine the photographic methods are at least a supplement to pharmacological testing with cocaine, which is sometimes equivocal and always delays the localizing hydroxyamphetamine test. The advantage of using a camcorder is the immediate evaluation on a TV screen. Because of the similar price it is more useful to buy an infrared camera to perform real pupillography. Because of the missing possibility of magnification we prefer the evaluation of slides instead of Polaroid flash photographs.

Adolescent↗

PubMed1994

[Objective vernier acuity testing in adults, children and infants. Possibilities and limits of a new method].

BACKGROUND: Recently, a method of objective Vernier acuity testing using a modified Catford drum was presented. A tight correlation between the objective Vernier acuity and the Snellen acuity was reported (Hopkisson et al. 1991). PATIENTS AND METHODS: In 41 cooperative patients with strabismic amblyopia and 20 normal subjects were compared the subjective Landolt acuity with the objective Vernier acuity and the individual interocular differences of the objective Vernier acuity. The Vernier method was then tested in 44 healthy 6- to 36-months-old infants. In 39 of the amblyopic and 15 of the normal subjects we compared the Landolt acuity with the grating acuity as measured with the Teller-acuity-card-test, and the interocular differences of the grating acuity. The Vernier target was a black line with an offset of one fifth of its thickness. In a distance of 1 m the offset appeared under visual angles of 15.9' to 0.3' corresponding to acuities of 0.06 to 3.2. The line was moving back and forth in its longitudinal direction. The objective Vernier acuity was defined by the smallest offset causing pursuit eye movements. RESULTS: Strabismic amblyopia was detected by the Vernier method with a sensitivity of 54%. In infants, however, the sensitivity would be less than 30%. In both eyes only 45% of the infants could be tested at all. The sensitivity of the Teller-acuity-card-test was 28%. CONCLUSION: Many cases of strabismic amblyopia will escape detection by the described method of Vernier acuity testing.

Adolescent↗