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Daniel S Mojon

Publications and source records attributed to Daniel S Mojon.

At least 19 recordsLinked to original sources
PubMed2006

Waiting times for cataract surgery in ten European countries: an analysis using data from the SHARE survey.

AIMS: To assess waiting times for cataract surgery and their acceptance in European countries, and to find explanatory, country-specific health indicators. METHODS: Using data from the survey of health, ageing and retirement in Europe (SHARE), waiting times for cataract surgery of 245 respondents in ten countries were analysed with the help of linear regression. The influence of four country specific health indicators on waiting times was studied by multiple linear regression. The influence of waiting time and country on the wish to have surgery performed earlier was determined through logistic regression. Additional information was obtained for each country from opinion leaders in the field of cataract surgery. RESULTS: Waiting times differed significantly (p<0.001) between the ten analysed European countries. The length of wait was significantly influenced by the total expenditure on health (p<0.01) but not by the other country specific health indicators. The wish to have surgery performed earlier was determined by the length of wait (p<0.001) but not by the country where surgery was performed. CONCLUSION: The length of wait is influenced by the total expenditure on health, but not by the rate of public expenditure on health, by the physician density or by the acute bed density. The wish to have surgery performed earlier depends on the length of wait for surgery and is not influenced by the country.

Aged↗
PubMed2006

Development of visual pursuit in the first 6 years of life.

BACKGROUND: There are few previous investigations on the development of smooth visual pursuit in children. The aim of this study was to determine normative values for the development of horizontal and vertical smooth pursuit in a large number of normal children. METHODS: Eye movements of 358 healthy children aged 6 weeks through 6 years were recorded using infrared photo-oculography. Visual pursuit was elicited with colored squares of 1.2 degrees of visual angle. The stimulus moved horizontally or vertically with constant velocities of 7.5, 15, or 30 degrees/s. RESULTS: Attention time increased with increasing age from 0.54 to 0.77 (P<0.01) and decreased with increasing stimulus velocities (P<0.01). The ratio of time of smooth pursuit to time of smooth pursuit plus saccades increased with increasing age from 0.63 to 0.78 (P<0.01) and decreased with increasing stimulus velocities (P<0.01). For stimulus velocities of 7.5 degrees/s, no significant difference was found between horizontal and vertical gain values. For stimulus velocities of 15 degrees/s and 30 degrees/s, gains for horizontal movements were larger that for vertical (P<0.05). Increasing stimulus speeds were associated with decreasing gains (P<0.05). CONCLUSIONS: This study provides the following normative values for photo-oculography in healthy children aged 6 weeks through 6 years of age: attention time, smooth pursuit time, and gain for three stimulus velocities presented horizontally and vertically. This normative database should help to diagnose pathologic ophthalmological or neuropediatric conditions, to perform screening interventions, and to initiate therapies.

Child↗
PubMed2006

Influence of the Pulfrich phenomenon on driving performance.

BACKGROUND: The Pulfrich stereoillusion occurs spontaneously in diseases inducing asymmetric visual pathway delays. Its influence on driving performance has never been investigated and was, therefore, assessed using a three-dimensional (3D) computer driving simulation. METHODS: A 3D driving scenery of a road with obstacles was visualised on an autostereoscopic 3D display. Seven normal subjects drove at a speed of 6 m/s using a steering wheel and three angles of view of the scenery (0 degrees, 45 degrees to left, and 90 degrees to left) with different interocular delays (25 ms on the right, 25 ms on the left, and no delay). One subject drove the scenery at an angle of 90 degrees without delay and with a delay of 8 ms, 16 ms, and 25 ms on the right and left, respectively, at speeds of 6 m/s, 12 m/s and 18 m/s. RESULTS: Stereo-illusion only influenced car position if the angle of view was 90 degrees (p<0.05). At this angle, increasing car speeds were associated with larger car displacements (delay on right p<0.001, on left p<0.01) and smaller delays with smaller car displacements (p<0.001). CONCLUSIONS: This study showed that Pulfrich phenomenon has an influence on car position only if the viewing angle is 90 degrees. No influence could be found if the driving direction corresponded to the visual axis of the driver. These findings are in agreement with reports of patients with spontaneous Pulfrich phenomenon who indicate that while driving, distances are only misjudged when looking sideways.

Adult↗
PubMed2006

A new 3D monitor-based random-dot stereotest for children.

PURPOSE: Objective testing for random-dot stereovision in preverbal children requires some type of dissociating glasses. Drawbacks of such methods are the alteration of natural visual conditions and sometimes nonacceptance of the glasses. For this reason, a new, natural method for random-dot stereopsis measurement was developed and tested. METHODS: Random-dot circles (diameter 10 cm, crossed disparity of 0.34 degrees ) were generated on an autostereoscopic display and presented to 18 normal children (mean age, 5.1 +/- 1.1 years), 8 with anisometropic amblyopia (mean age, 4.9 +/- 1.3 years), 14 with infantile essential esotropia (mean age, 5.3 +/- 0.7 years), and 16 with primary microstrabismus (mean age, 5.2 +/- 1.4 years). While the position of the stimulus randomly changed among four possible locations, eye positions were recorded by infrared photo-oculography. If two or more consecutive saccades ends corresponded to the stimulus coordinates, a positive response was assumed. The results with the new test were compared with the ability to recognize the Lang I random-dot stereotest. RESULTS: Twenty-four of 26 Lang I-positive children had positive responses (sensitivity of 92.3%), 29 of 30 Lang I-negative children had negative three-dimensional (3D) stimulus responses (specificity, 96.7%). The positive predictive value of the new test was 0.96 (95% CI, 0.79-0.99); the negative predictive value, 0.94 (95% CI, 0.78-0.99); and the overall accuracy, 0.95 (95% CI, 0.85-0.99). CONCLUSIONS: This new 3D monitor-based test allows objective assessment of random-dot stereopsis in children older than 3 years.

Amblyopia↗
PubMed2004

Redundant publications in scientific ophthalmologic journals: the tip of the iceberg?

OBJECTIVE: The number of scientific publications is often used to measure scientific achievement. This practice can motivate unethical conduct, such as redundant or duplicate publications, defined as publication of the same scientific contents in more than 1 journal. The aim of this study was to estimate the amount of redundant publications in ophthalmologic journals. DESIGN: Retrospective analysis of published literature. METHODS: We developed an electronic search engine for redundancies to estimate the amount of duplicate publications in scientific journals. When redundancies reached a given degree (matching score), the articles were screened manually based on authors, titles, and abstracts. We applied this method to the 22 433 articles that were published between 1997 and 2000 in 70 ophthalmologic journals indexed by MEDLINE. MAIN OUTCOME MEASURES: The number of duplicate publications with a matching score of 0.6 or more, the number of involved journals, and the number of authors. RESULTS: Redundancies reached a matching score of 0.6 or more in 13 967 pairs of articles. Out of them, a sample of 2210 was reviewed manually. We found 60 redundant articles and estimated that 1.39% of the publications were redundant. Thirty-two journals and an estimate of 1092 authors were involved. In 5% of cases, the scientific conclusions were modified. CONCLUSIONS: Because of the restrictive selection process, the impracticability of detecting all redundant publications, and the estimated amount of duplicates increases with lower matching scores, we regard our estimate to be the tip of the iceberg. Duplicate publications have several negative impacts, but neither peer reviewers nor editors can protect their journal from them completely. Several deterrents for duplicate publications are possible, but as long as publications remain the central requirement for academic advancement, a solution seems unlikely. Nevertheless, it is the responsibility of all those who care about objective research and evidence-based medicine to address this problem-not only in ophthalmology.

Algorithms↗
PubMed2003

Detection of nonorganic visual loss with a new optotype chart in simulated malingerers.

BACKGROUND: We tested a new distance and pocket optotype chart for detection of nonorganic symmetrically decreased vision in simulated malingerers. The new optotype used in the charts is based on a subjective contour formed by a misalignment of two line segments. The minimum angle of resolution of this optotype is independent of its size. Subjects claiming to see only the larger optotypes are suspected of malingering. SUBJECTS AND METHODS: 90 normal subjects were asked to simulate symmetrically decreased vision. 60 of these subjects were tested with a distance chart and 30 with a pocket chart. The distance chart was always presented at a fixed distance of 5 m. The pocket chart was moved towards the malingerer until the largest optotype was clearly legible. RESULTS: With the distance chart, 62 % (37/60) of all simulated patients claimed to recognize only the larger optotypes, 33 % (20/60) claimed not to recognize any optotype size, and 5 % (3/60) were able to read all optotype sizes. With the pocket chart, 84 % (25/30) of all simulated patients claimed to recognize only the larger optotypes, 3 % (1/30) claimed not to recognize any optotype size, and 13 % (4/30) were able to read all optotype sizes. The difference between the two distributions of behavior was statistically significant (chi-square statistic, P < 0.005). CONCLUSIONS: Movement of the chart towards the subject (pocket chart) was better at detecting nonorganic visual loss than using a fixed distance (distance chart). Therefore, we suggest to use the pocket chart for the detection of nonorganic disease.

Chi-Square Distribution↗
PubMed2003

[A new objective visual acuity test: an automated preferential looking].

BACKGROUND: The Preferential Looking test using Teller acuity cards is widely used for preverbal children but has some weaknesses, in particular because it is examiner dependent and at best half-objective. We tested a new automated method in a pilot study. PATIENTS AND METHODS: In our preferential looking setting we project separate images into the left and right eye. This permits measuring each eye without having to cover the other. An infrared oculography system documents objectively and reproducibly whether or not the stimulus is seen. A square is shown which moves consecutively in a square formation on a background that has the same average brightness. Charting an XY-plot of the eye position results in a square with two diagonals, if the stimulus is seen. By using a specific baby examination unit, this test is already feasible in babies. In this study, the new setting was tested on two children. RESULTS: In two healthy children we found a good correlation between visual acuities determined with the new method and Teller visual acuity charts. Fogging one eye in each of the children resulted in fixation loss of the stimulus when the required visual acuity rose above the fogging value. CONCLUSIONS: This new technique permits one to perform an objective preferential looking test without the need of verbal answers. Larger studies have to validate these preliminary results.

Attention↗
PubMed2003

[A new objective test for random-dot stereopsis in preverbal children].

BACKGROUND: The Lang-Stereotest is at best half-objective in testing stereovision in preverbal children. We developed a new method which might objectively measure random-dot stereopsis in preverbal children. PATIENTS AND METHODS: We project two separate random-dot images into the left and right eye using a 3D-monitor. If both eyes are perfectly aligned and random stereopsis is present, the child perceives a stimulus. Four different stimulus positions are shown at random. An infrared oculography system objectively detects whether the stimuli are seen. By using a specific baby examination unit, testing is already feasible in infants. RESULTS: We present the plots of two children with a positive (normal) and two with a negative (pathologic) response to random-dot stimuli. CONCLUSIONS: This new examination technique allows an objective assessment of random-dot stereopsis in non-verbal children. It permits us for the first time to study the development of stereovision under natural conditions. In future, the method may also be used to screen preverbal children for visual abnormalities. Larger studies are required to determine the positive and negative predictive values of this new test.

Child, Preschool↗
PubMed2003

[A new method to test vertical ocular deviations using perilimbal light reflexes].

BACKGROUND: To develop a new diagnostic technique to determine vertical ocular deviations when the center of the pupil is covered by swollen eyelids in up- and downgaze. PATIENTS AND METHODS: In upgaze (downgaze) the reflex of a diagnostic lamp held at about 50 cm distance from the patient is observed on the lower (upper) limbus. In the case of an asymmetric reflex, prisms are used to obtain symmetrical reflexes. The amount of prisms indicates the size of the vertical misalignment. In five healthy volunteers, the angles of vertical changes of gaze position were plotted against the prism size needed to recenter the perilimbal reflex. RESULTS: There was a linear correlation between the amount of upgaze changes in degrees and the strength of prisms used for compensation in degrees. This linear correlation was also found in downgaze. For both the correlation coefficient was r = 0.98 +/- 0.01. In upgaze the slope of the average regression line was 0.55 +/- 2.3 degrees, in downgaze - 4.1 +/- 0.8 degrees. A prism of 1 degrees corresponds in upgaze to a vertical deviation of about 1.3 +/- 0.14 degrees, in downgaze to a deviation of about 1.1 +/- 0.07 degrees. CONCLUSIONS: These results demonstrate that the perilimbal light reflex test is suitable for measuring simulated vertical ocular deviations. Therefore, the test may also be used in patients with vertical deviations who cannot be measured with classical methods. The method is more exact for measurements in upgaze.

Adult↗
PubMed2003

[Orbital blow-out fractures, a series of 12 operated cases].

BACKGROUND: The management for blow-out fractures is controversial. Some studies suggest early surgical treatment, others a conservative attitude. PATIENTS AND METHODS: We studied retrospectively the data of patients with blow-out fracture, referred to our Neuro-Ophthalmology and Strabismus Clinic from July 1993-May 2000. Out of 48 patients, 22 were operated. We evaluated all 12 patients who underwent pre- and postoperative orthoptic examinations. RESULTS: The patients' age at the time of the accident was 7.8 to 67.8 years (median 25.3). The delay between accident and operation was 2 to 91 days (median 5.5). Eleven patients were operated within 14 days, one after three months. All patients suffered preoperatively from double-vision. Postoperatively the field of fusion augmented, the middle point centralised. The follow-up time was 22 to 915 days (median 251). However, at the last examination, 0.5 to 16 months (median 4.5) after surgery, only seven out of 12 patients were symptom-free. CONCLUSION: Surgical reconstruction within the first week after trauma shows good results concerning ocular motility, sensibility, enophthalme, and field of fusion. An individual evaluation is surely necessary.

Adolescent↗
PubMed2002

Association between sleep apnea syndrome and nonarteritic anterior ischemic optic neuropathy.

OBJECTIVE: To determine if patients with nonarteritic ischemic optic neuropathy (NAION) have sleep apnea syndrome (SAS), an entity characterized by repetitive upper airway obstructions during sleep, inducing hypoxia and sleep disruption. METHODS: We recruited 17 patients with NAION and 17 age- and sex-matched controls from patients referred for treatment because of suspected restless legs syndrome. We performed overnight polysomnography and determined the respiratory disturbance index during night sleep, a value used to diagnose and grade SAS. We compared the proportions of patients with SAS among patients with NAION and matched controls using the chi(2) test. Additionally, we compared the proportions of patients with SAS among patients with NAION and a large SAS prevalence study using the binomial test. RESULTS: Twelve (71%) of 17 patients with NAION had SAS. According to the respiratory disturbance index, 4 patients (24%) had mild, 4 patients (24%) had moderate, and 4 patients (24%) had severe SAS. Only 3 (18%) of 17 controls had SAS (P =.005). In the 45- to 64-year age group, 4 (50%) of 8 patients with NAION had SAS; 51 (11.9%) of 430 of the random sample in the prevalence study had SAS (P =.005). In the group older than 64 years, 8 (89%) of 9 patients with NAION had SAS; 18 (24%) of 75 of the random sample in the prevalence study had SAS (P<.001). CONCLUSIONS: We found a high prevalence of SAS in patients with NAION, which supports previous case reports suggesting that such an association exists. This association may explain why approximately 75% of all patients with NAION discover visual loss on first awakening or when they first use vision critically after sleeping. Our findings indicate that SAS may play an important role in the pathogenesis of NAION.

Aged↗
PubMed2002

A new optotype chart for detection of nonorganic visual loss.

OBJECTIVE: To develop a new optotype chart for detection of nonorganic decreased vision. DESIGN: Comparative observational case series. PARTICIPANTS: Optotype thresholds determination in three normal subjects and testing on 30 consecutive patients with unclear visual acuity loss. METHODS: A new optotype chart was developed, with an optotype minimum angle of resolution that is independent of size. In three normal subjects rank correlation was calculated between the optotype thresholds and the optotype sizes. A pocket chart was tested in a masked manner on 30 consecutive patients referred because of unclear visual acuity loss. MAIN OUTCOME MEASURES: Optotype thresholds and usefulness in clinical routine (positive and negative predictive values including 95% confidence intervals [CI]). RESULTS: The optotype thresholds did not correlate with the optotype sizes. Ten percent (3 of 30) of the patients referred because of unclear visual acuity loss had to be excluded, because their diagnosis remained unclear. All patients (16 of 16) with organic visual loss saw all optotypes sizes. Eighty-nine percent (10 of 11) of patients with nonorganic visual loss claimed to see only the larger optotypes. The positive predictive value for nonorganic visual loss of the new pocket chart was 100% (CI, 74%-100%); the negative predictive value was 94% (CI, 75%-100%). CONCLUSIONS: The new pocket chart seems to be useful for detection of visual loss caused by nonorganic disease.

Adolescent↗
PubMed2002

The Pulfrich phenomenon in a large population of young healthy subjects.

BACKGROUND: To determine whether the Pulfrich phenomenon, an optical illusion occurring in many ophthalmological diseases, is perceived equally in both eyes in a large group of healthy medical students. SUBJECTS AND METHODS: A pendulum bob swinging perpendicular to the direction of observation was observed with either the right or the left eye covered with neutral density filters (50, 80 or 90 % absorption) and the apparent elliptical pendulum movement measured in depth. Interocular time delay was calculated from depth. Data from 65 individuals were included based on having: completed all 7 determinations of depth, a visual acuity of >/= 20/20 on both eyes and an intact stereoscopic perception (Titmus stereotest, acuity of >/= 20/25). RESULTS: All subjects perceived the phenomenon. Depth perception was not significantly different (p > 0.05; MANOVA) between the two eyes (depth in [mm]; mean +/- sem): OD: 8.5 +/- 0.38, 23.7 +/- 0.53, 36.3 +/- 0.81; OS 9.4 +/- 0.50, 24.1 +/- 0.69, 35.6 +/- 0.92; for 50, 80 and 90 % absorption of the filter respectively. At 0 % absorption the pendulum was seen in average at positive values (0.9 +/- 0.23 mm; p > 0.05). Calculated interocular time delay (ms) was: OD: 8.0 +/- 0.18, 5.1 +/- 0.12, 1.8 +/- 0.08; OS: 7.46 +/- 0.15, 5.0 +/- 0.11, 1.9 +/- 0.10. The average depth perceived without filter corresponded to a time delay for the right eye of 0.2 +/- 0.05 ms. Correction for the depth perception perceived without filter did not alter statistical significance. CONCLUSIONS: The Pulfrich phenomenon is perceived equally in both eyes. Depth perception without filters was not significantly different from zero. The illusion has clinical utility, since in normal subjects reliability of measurements is good and size of the illusion (without filters) small.

Adult↗
PubMedDate not supplied

Normal-tension glaucoma is associated with sleep apnea syndrome.

INTRODUCTION: In normal-tension glaucoma, optic nerve damage occurs without elevated intraocular pressures, hence vascular and pathogenic mechanisms other than intraocular pressure effects have been postulated. However, the exact cause(s) remain unknown. We have looked for an association between normal-tension glaucoma and sleep apnea syndrome, a disease characterized by repetitive upper airway obstructions during sleep, inducing hypoxia and sleep disruption with the risk of late cardiovascular and neurological sequelae. METHODS: We performed overnight polysomnography in 16 consecutive Caucasian patients with normal-tension glaucoma. The respiratory disturbance index (RDI) during night sleep was used to diagnose and grade obstructive sleep apnea. Patients with an RDI of 10 or more were diagnosed as having obstructive sleep apnea. RESULTS: We observed the following prevalences of obstructive sleep apnea in normal-tension glaucoma patients: 0% (0 of 2) for the group of patients younger than 45 years, 50% (3 of 6) for the age group 45-64 years, and 63% (5 of 8) for the group older than 64 years. Prevalences in the middle and older age group were significantly higher than in a historic control group (p < 0.025 for both, binomial test). CONCLUSION: Normal-tension glaucoma patients constitute a high-risk population for sleep apnea syndrome. Therefore, they should be screened for sleep apnea syndrome, and, if necessary, be treated to avoid late cardiovascular and neurological sequelae.

Adult↗
PubMedDate not supplied

Deep sclerectomy with collagen implant: initial experience.

OBJECTIVE: To evaluate complications of deep sclerectomy with collagen implant (DSCI), a recently introduced nonpenetrating glaucoma-filtering surgical technique. PATIENTS AND METHODS: 30 eyes of 23 patients with open-angle glaucoma were included in this prospective, noncomparative, interventional case series. In all eyes, preoperative intraocular pressure (IOP) was lowered inadequately by topical antiglaucomatous medications. After undergoing DSCI, the patients were followed prospectively. If necessary, the procedure was combined with cataract surgery or mitomycin C application. RESULTS: In 27 (90%) of 30 eyes, DSCI could be performed. In 3 (10%) of 30 eyes, DSCI had to be transformed intraoperatively into a trabeculectomy because of a large trabecular penetration. Microperforations without further consequences occurred in 2 (7%) of 30 eyes. The mean follow-up was 6.6 +/- 3.8 months. IOP dropped from 26.0 +/- 6.7 to 13.6 +/- 4.7 mm Hg (p < 0.05). Medical glaucomatous treatment was reduced from 2.3 +/- 3.8 to 0.3 +/- 0.6 (p < 0.05). In cases without cataract, visual acuity decreased from 0.7 +/- 0.3 to 0.66 +/- 0.4 at the last visit (p > 0.1). Postoperative complications included Seidel (1/27, 4%), encapsulated bleb (4/27, 15%), astigmatism (1/27, 4%), iris capture (2/27, 7%), microhyphema (3/27, 11%) and peripheral anterior synechiae (4/27, 15%). Fifteen (56%) of the 27 eyes needed the following postoperative procedures: laser goniopuncture (8/27, 30%), needling of the filtering bleb (4/27, 15%), surgical revision in the operating theater (3/27, 11%). All 3 eyes where trabeculectomy was performed instead of DSCI had a favorable course. CONCLUSIONS: During the evaluation period, complications occurred in about half of the cases. None of the complications was severe or irreversible. Target pressure and a reduction in drug treatment could be achieved in all of the patients.

Aged↗
PubMedDate not supplied

Normal isopter position in the peripheral visual field in goldmann kinetic perimetry.

PURPOSE: Often in young patients the question arises if a disease state has contracted their peripheral boundary of the visual field. Since the 'hill of vision' is steeper in the periphery, kinetic perimetry is more sensitive in detecting peripheral visual field abnormalities than static perimetry. In order to be able with kinetic perimetry to detect mild peripheral visual field constrictions, we determined the normal position of 4 isopters in the peripheral visual field. SUBJECTS AND METHODS: Intraindividual sensitivity variations of the isopters in the peripheral visual field were determined in 3 normal subjects by one perimetrist. Then, in 22 subjects (19-42 years old) the position of the isopters V4e, III4e, I4e and I3e has been determined by one perimetrist. Visual fields were registered using a Goldmann kinetic perimeter. RESULTS: The intraindividual sensitivity variations (measured as 1 standard deviation) for the isopter V4e was 0.98 degrees and for the isopter I4e 1.13 degrees. To visualize the normal isopter positions in the peripheral visual field, the average positions +/- 2 standard deviations were plotted for the isopters V4e, III4e, I4e and I3e. CONCLUSION: In this study, we determined the normal position of 4 isopters frequently used to plot the peripheral visual field. The plots have been printed in a scale of 1:4 in order to facilitate its use. Photocopying the figures on transparencies by scaling them with a factor 4 will allow to superpose the transparencies on individual Goldmann kinetic visual fields in order to easily determine whether the individual isopters are inside or outside the normal range.

Adult↗