Bagolini filter bars: an analysis of light transmittance and their use in a pediatric population.

Purpose: The purpose of this study is to determine whether the Sbisa bar (Sbisa Ophthalmic Instruments) (referred to in this article as the BF(Sbisa) bar) and Bagolini Filter bar (C.O.I. Vision) (referred to in this article as the BF(new) bar) are repeatable and comparable, for measuring density of suppression or strength of abnormal binocular single vision (BSV), in a pediatric population. Methods: Using a spot photometer, percentage light transmittance of filters on two BF(Sbisa) bars and two BF(new) bars was measured. Thirty-three participants aged 5-12 years with unilateral strabismus were recruited. Density of suppression or strength of abnormal BSV was measured with two of each bar, in addition to a repeated measure with one of each bar. Results: Light transmittance did not reduce consistently with increasing filter number (the number assigned to each filter by the manufacturer). Using data as filter numbers, a BF(Sbisa) bar was not comparable to a BF(new) bar (ᵶ = -3.936, p < 0.001, r = -0.28); different BF(Sbisa) bars were not comparable (ᵶ = -3.103, p = 0.005, r = -0.22) but different BF(new) bars were comparable (ᵶ = -1.165, p = 1.285, r = -0.08). Using light transmittance values, a BF(Sbisa) bar was comparable to a BF(new) bar (ᵶ = -0.385, p = 3.535, r = -0.03); different BF(Sbisa) bars were comparable (ᵶ = -1.476, p = 0.720, r = -0.10) but different BF(new) bars were not comparable (ᵶ = -3.354, p < 0.001, r = -0.24). The BF(Sbisa) and BF(new) bars were not repeatable using filter numbers (ᵶ = -3.648, p < 0.001, r = -0.26 and ᵶ = -3.099, p = 0.005, r = -0.22, respectively) or light transmittance values (ᵶ = -3.743, p < 0.001, r = -0.27 and ᵶ = -2.727, p = 0.025, r = -0.19, respectively). An order effect existed using filter numbers (ᵶ = -4.473, p < 0.001, r = -0.32) and light transmittance values (ᵶ = -4.525, p < 0.001, r = -0.32). Conclusion: There is a need for the production of bars with consistently reducing and comparable light transmittance of filters if measurement of density of suppression or strength of abnormal BSV with filter bars is to continue, because the current bars show inconsistencies, particularly at lower filter numbers. In the meantime, the bars are limited by their lack of comparability or repeatability. Using only BF(new) bars is preferable to using BF(Sbisa) bars or a mixture of the two types of bar because two different BF(new) bars may be comparable using filter number readings, but filter number readings from different BF(Sbisa) bars or from a BF(Sbisa) and BF(new) bar are not comparable. As the BF(Sbisa) and BF(new) bars are currently labeled, a second measure of density of suppression or strength of abnormal BSV is not recommended within 2 min of an initial measurement, because the measurement procedure seems to cause a reduction in suppression or abnormal BSV that does not recover with repeated measurements 2 min apart.

Is conversion of decimal visual acuity measurements to logMAR values reliable?

PURPOSE: To assess if conversion of decimal visual acuity (VA) to logMAR is reliable for clinical and research purposes. METHODS: Right eye VA of 74 consecutive patients was measured with 5 min interval, using (a) the ETDRS chart (VAlog), (b) a decimal chart at 6 m (VA6m), and (c) a decimal chart at 4 m (VA4m). VA was the smallest line whereby four of five optotypes were correctly identified. Decimal scores were converted to logMAR using the formula logMAR = -log(decimal acuity). The agreement between VAlog, VA4m, and VA6m was assessed by the Bland-Altman method. RESULTS: Linear regression analysis of the difference between VAlog and VA6m or VA4m showed a significant slope (p = 0.001), with greater disagreement at higher VA values, i.e., poorer acuity. There was considerable lack of agreement, with discrepancies of up to 0.2 logMAR when VA was measured around 0.5 logMAR. CONCLUSION: Converting decimal VA to logMAR produces overestimation of its true value, especially in lower acuities.

Home use of binocular dichoptic video content device for treatment of amblyopia: a pilot study.

PURPOSE: To evaluate the efficacy of the BinoVision home system as measured by improvement of visual acuity in the patient's amblyopic eye. METHODS: An open-label prospective pilot-trial of the system was conducted with amblyopic children aged 4-8 years at the pediatric ophthalmology unit, Tel-Aviv Medical Center, January 2014 to October 2015. Participants were assigned to the study or sham group for treatment with BinoVision for 8 or 12 weeks. Patients were instructed to watch animated television shows and videos at home using the BinoVision device for 60 minutes, 6 days a week. The BinoVision program incorporates elements at different contrast and brightness levels for both eyes, weak eye tracking training by superimposed screen images, and weak eye flicker stimuli with alerting sound manipulations. Patients were examined at 4, 8, 12, 24, and 36 weeks. RESULTS: A total of 27 children were recruited (14 boys), with 19 in the treatment group. Median age was 5 years (range, 4-8 years). Mean visual acuity improved by 0.26 logMAR lines in the treatment group from baseline to 12 weeks. Visual acuity was improved compared to baseline during all study and follow-up appointments (P < 0.01), with stabilization of visual acuity after cessation of treatment. The sham group completed 4 weeks of sham protocol with no change in visual acuity (P = 0.285). The average compliance rate was 88% ± 16% (50% to 100%) in treatment group. CONCLUSIONS: This pilot trial of 12 weeks of amblyopia treatment with the BinoVision home system demonstrated significant improvement in patients' visual acuity.

[Assessment of a 3D digital orthoptic test platform]. / Évaluation d'une plateforme d'orthoptie numérique 3D.

PURPOSE: To compare standard orthoptic tests with a novel digital 3D orthoptic platform, 3DeltaEasy(©) from Orthoptica(®). MATERIALS AND METHODS: This study tests the 3D digital orthoptics platform, 3DeltaEasy(©) from Orthoptica(®) and compares it to the corresponding standard orthoptic tests. This platform consists of a computer equipped with dedicated software, a video projector and 3D liquid crystal glasses. Three tests were compared: Wirt test, measurement of horizontal and vertical phorias, and the horizontal fusional amplitude in convergence and divergence. A total of 102 subjects, 53 males (52 %) and 49 females (48 %), aged between 9 years and 72 years (mean age 33±16.4 years) were examined at the ophthalmologic department of the Brest Hospital (France) and included in this observational cross-sectional study. Subjects recruited in this study were patients requiring orthoptic screening or therapy. Patients without their optimal visual corrections were excluded. All patients underwent both ophthalmological and orthoptic examination including Wirt fly stereotest with polarizing spectacles, cover tests to evaluate and measure the horizontal and vertical deviation of the lines of sight, horizontal vergence ranges using prism bar and their equivalent tests implemented in the digital 3D orthoptic tests 3DeltaEasy(©) from Orthoptica(®). RESULTS: All data were processed using MedCalc Statistical Software version 14.12.0 (MedCalc Software bvba, Ostend, Belgium). The main result of this study is that 3DeltaEasy(©) and the classical Wirt test are correlated (Spearman's coefficient of rank correlation: ρ=0.74; P<0.0001), cover tests are equivalent for intermediate and far vision (paired t-test; P=0.46 and P=0.51), and horizontal and vertical vergence range are comparable for distance vision (paired t-test; P=0.34 and P=0.94). CONCLUSION: New digital 3D tools could easily substitute for some orthoptic tests with better ergonomics. Eventually, by increasing the number of tests performed, it could substitute for nearly all tests.

Assessing interventions to increase compliance to patching treatment in children with amblyopia: a systematic review and meta-analysis.

BACKGROUND/AIMS: Amblyopia is the most common condition affecting visual acuity in childhood. Left untreated it will not resolve itself, leading to increased risk of blindness. Occluding the good eye with a patch is a highly effective treatment if carried out before age 7 years but compliance is a major problem. This systematic review addresses the question: How effective are existing interventions at increasing compliance to patching treatment in children with amblyopia? METHODS: Electronic searches were carried out in June 2014 and updated in April 2015 to identify studies reporting primary data on interventions to increase patching compliance. Data screening, extraction and quality ratings were performed independently by two researchers. RESULTS: Nine papers were included. Interventions including an educational element (5 studies) significantly increased patching compliance and had higher quality ratings than interventions that changed aspects of the patching regime (3 studies) or involved supervised occlusion (1 study). Meta-analysis was conducted on four studies and indicated that overall interventions involving an educational element have a significant small effect r=0.249, p<0.001. CONCLUSIONS: Interventions to increase patching compliance should include educational elements. High quality research is needed to further assess the effectiveness of specific elements of educational interventions and additional behaviour change techniques.

Fresnel prism use among orthoptists.

PURPOSE: To better understand current uses of Fresnel prisms. METHODS: A seventeen-question survey was completed by members of the American Association of Certified Orthoptists (AACO). RESULTS: Surveys were emailed to 211 orthoptists with a 36% response rate (n = 76). Prisms are used preoperatively to determine the surgical angle for 72% of respondents, 94% use prisms for postoperative misalignment. Prisms are used for incomitant deviations by up to 96% of respondents. The greatest patient objection to Fresnel use is reduced vision and distortion, not diplopia out of primary position. Of orthoptists surveyed, 99% use Fresnel prisms for near-distance disparity, 36% splitting prisms for upper and lower segments, and 40% encourage separate spectacles for near and distance. When deciding to grind prism, 66% wait more than one month. Ninety-nine percent of orthoptists use Fresnel prisms with adults, 67% use them with children. When correcting vertical and horizontal deviations, 70% of orthoptists rotate a prism over one lens. CONCLUSION: Fresnel prisms have a wide use among North American certified orthoptists, including use with pediatric patients. Incomitance is not a contraindication to Fresnel use. Orthoptists prefer rotating one prism to bilateral Fresnel prisms.

Accuracy of double Maddox rod with induced hypertropia in normal subjects.

BACKGROUND AND PURPOSE: The double Maddox rod is a commonly used instrument to test for cyclotorsion in the clinical setting. This paper assesses the ability of patients without torsional complaint to accurately demonstrate torsional status with varying degrees of induced hypertropia as tested by double Maddox rod. METHODS: Thirty-seven orthophoric subjects underwent double Maddox rod testing with vertical prism of 3(Δ), 10(Δ), 16(Δ), 20(Δ), and 30(Δ). Subjective torsion was recorded for each prism diopter. RESULTS: Mean subjective torsion was recorded as 0.95°, 1.6°, 1.9°, 2.1°, and 2.2° for 3(Δ), 10(Δ), 16(Δ), 20(Δ), and 30(Δ), respectively. Torsion increased in a logarithmic manner as modeled by R™ software version 2.15.2. CONCLUSIONS: The double Maddox rod test as commonly used in clinical practice is both subjective and prone to administrator and subject error. Subjects have more difficulty properly aligning the double Maddox rod as distance between images is increased. It is also possible that recruitment of the oblique muscles during attempted vertical fusion leads to subjective torsion during double Maddox rod testing in otherwise normal participants.

Comparison of optotypes of Amsterdam Picture Chart with those of Tumbling-E, LEA symbols, ETDRS, and Landolt-C in non-amblyopic and amblyopic patients.

PURPOSE: To compare optotypes of the Amsterdam Picture Chart (APK) with those of Landolt-C (LC), Tumbling-E (TE), ETDRS and LEA symbols (LEA), to assess their reliability in measuring visual acuity (VA). METHODS: We recruited healthy controls with equal VA and amblyopes with ≥2 LogMAR lines interocular difference. New logarithmic charts were developed with LC, TE, ETDRS, LEA, and APK with identical size and spacing (four optotypes) between optotypes. Charts were randomly presented at 5 m under DIN EN ISO 8596 and 8597 conditions. VA was measured with LC (LC-VA), TE, ETDRS, LEA, and APK, using six out of ten optotypes answered correctly as threshold. RESULTS: In 100 controls aged 17-31, LC-VA was -0.207 ± SD 0.089 LogMAR. Visual acuity measured with TE differed from LC-VA by 0.021 (positive value meaning less recognizable), with ETDRS 0.012, with Lea 0.054, and with APK 0.117. In 46 amblyopic eyes with LC-VA <0.5 LogMAR, the difference was for TE 0.017, for ETDRS 0.017, for LEA 0.089, and for APK 0.213. In 13 amblyopic eyes with LC-VA ≥0.5 LogMAR, the difference was for TE 0.122, ETDRS 0.047, LEA 0.057, and APK 0.019. APK optotypes had a lower percentage of passed subjects at each LogMAR line compared to Landolt-C. The 11 APK optotypes had different thresholds. CONCLUSIONS: Small APK optotypes were recognized worse than all other optotypes, probably because of their thinner lines. Large APK optotypes were recognized relatively well, possibly reflecting recognition acuity. Differences between the thresholds of the 11 APK optotypes reduced its sensitivity further.

An educational intervention to improve adherence to high-dosage patching regimen for amblyopia: a randomised controlled trial.

BACKGROUND: Previous reports suggest that adherence to patching is a major issue in amblyopia treatment. We tested with an unmasked randomised controlled clinical trial whether an intense educational/motivational intervention improves adherence when a high-dose regime is prescribed. METHODS: 62 children with newly diagnosed amblyopia were randomly allocated into two treatment arms with and without educational/motivational intervention material. Both were prescribed patching 10 h/day, 6 days/week for a fixed period of 12 weeks. The intervention arm received an educational/motivational intervention before patching which included information booklets, video, a cartoon story book, sticker charts and a dedicated session with a researcher. The control arm received the usual clinical information. The primary outcome measure was adherence measured using electronic occlusion dose monitors where a success/failure binary outcome was used to account for participants who dropped out of the study defined as patching >4 h/day. Visual outcome, expressed as percentage visual deficit, was measured as secondary outcome. RESULTS: The intervention increased adherence success rate from 45.2% in the control group to 80.6% in the intervention group (p=0.0027). However, visual outcome was not significantly better in the intervention group (p=0.190). CONCLUSIONS: Our study shows that an intense educational/motivational intervention can improve adherence to patching to high prescribed doses although no significant improvement in visual outcome was observed. TRIALS REGISTRATION NUMBER: ISRCTN05346737 (International Standard Randomised Controlled Trial Number Register).

The orthoptic slit lamp.

Recently we presented our concept of "videography with the slit lamp," which provides an imaging solution for nearly every pathological finding in ophthalmology. This paper deals with the changes that must be made to prepare the slit lamp for documenting squint. To achieve this goal we propose: 1. Changes in the observation system: minus lenses in front of the objective of the slit lamp to achieve a sharp image of both eyes (eg, -8 diopters [dpt] if the patient sits at a distance of 50 cm). 2. Changes in the illumination system: minimizing the narrowed angle between illumination and observation axis by holding a "recentration" prism of 14 dpt horizontally in front of the slit light. This procedure creates equally sufficient illumination of the patient's face and central corneal reflexes. 3. Recording clinical findings with a digital recorder. This enables us to identify binocular eye positions, which sometimes last only part of a second, eg, in latent or intermittent strabism. 4. Visualizing clinical findings by using Microsoft PowerPoint® to build up 9-gaze composites or adjust corneal reflexes on subsequent foils. Changes in binocular eye positions (eg, after surgery, but also during diagnostic covering) can be made visible by flickering between the foils to compare.

Randomised comparison of three tools for improving compliance with occlusion therapy: an educational cartoon story, a reward calendar, and an information leaflet for parents.

BACKGROUND: We previously demonstrated that compliance with occlusion therapy for amblyopia was improved by the use of an educational programme, especially in children of parents of foreign origin and who spoke Dutch poorly. The programme consisted of: (i) a cartoon story for amblyopic children that explained without words why they should patch, (ii) a calendar with reward stickers, and (iii) an information leaflet for parents. In the current study, we assessed the individual effect of each component on compliance. METHODS: We recruited 120 3- to 6-year-old children who lived in a low socio-economic status (SES) area in The Hague and were starting occlusion therapy for the first time. They were randomised to receive one of the components (three intervention groups), or a picture to colour (control group). The randomisation was blinded for treating orthoptist and researcher. Compliance was measured electronically using the Occlusion Dose Monitor (ODM). Primary outcome was percentage of compliance (actual/prescribed occlusion time). Secondary outcome was absolute occlusion hours per day. Parental fluency in Dutch was rated on a five-point scale. RESULTS: Compliance could be measured electronically in 88 of the 120 children; in 32 others, it failed for various reasons. Parental fluency in Dutch was moderate or worse in 36.4 % (p = 0.327). Average compliance was 55 % standard deviation (SD) 40 (n = 18) in the control group, 89 % SD 25 in the group receiving the educational cartoon (n = 25, P = 0.002 compared with control group), 67 % SD 33 (n = 24, P = 0.301) in the reward-calendar group and 73 % SD 40 (n = 21, P = 0.119) in the parent-information-leaflet group. On average, children in the control group occluded 1:46 SD1:19 hours/day, 2:33 SD 1:18 hours/day in the group receiving the educational cartoon, 1:59 SD 1:13 hours/day in the reward-calendar group and 2:18 SD 1:13 hours/day in the parent-information-leaflet group. No child who received the cartoon story occluded less than 1 hour per day, against seven in the reward-calendar group, five in the parent-information-leaflet group and five in the control group. CONCLUSIONS: Although all three components of the programme improved compliance with occlusion therapy in children in low-SES areas, the educational cartoon had the strongest effect, as it explained without words to a 4- to 5-year-old child why it should wear the eye patch.

Validation and cost-effectiveness of a home-based screening system for amblyopia.

PURPOSE: To investigate the cost-effectiveness of a novel home-based screening system for amblyopia and amblyogenic risk factors. DESIGN: Evaluation of diagnostic test or technology. PARTICIPANTS: Two thousand four hundred forty-two preschoolers 3 to 6 years of age from 10 kindergartens randomly selected from Guangzhou participated in the study in 2009. METHODS: Preschoolers were assessed for amblyopia and amblyogenic risk factors by their parents using the home-based screening system and were re-evaluated by professionals who conducted a comprehensive eye examination. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive predictive value, negative predictive value, and the cost-benefit of the home-based screening system were calculated by comparing the results from the home-assessed model and those from the professional evaluation. RESULTS: Three thousand three hundred children were invited to participate in the study, and 2308 (1216 boys and 1092 girls) completed all of the procedures. Twenty-four amblyopes were found by professional examinations. Fifteen of these amblyopes had not been diagnosed previously, and 12 of them were detected by the home-assessment model. The sensitivity, specificity, positive predictive value, and negative predictive value were 80.0%, 94.1%, 8.2%, and 99.9%, respectively. Professional examinations cost an average of US $1131.00 per case of amblyopia detected, whereas the cost was only US $266.00 per case for the home-based method. For amblyogenic factors, 50, 87, and 96 children were classified into grade I, II, or III according to the professional examinations. The corresponding numbers in the home-based system were 23, 29, and 15, respectively. Accordingly, the true positive rates were 46.0%, 33.3%, and 15.6% for each grade. CONCLUSIONS: The home-based amblyopia screening system was found to be a simple, effective, and cost-beneficial method for amblyopia screening and amblyogenic risk factors. The approach offers a practical option for developing areas with large populations. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

[Electronically recorded occlusion treatment in amblyopes older than 7 years: acuity gain after more than 4 months of treatment?]. / Elektronisch erfasste Okklusionstherapie bei über 7-jährigen Amblyopen: Visusanstieg noch nach mehr als 4 Monaten?

BACKGROUND: According to the ROTAS study most of the improvement in visual acuity (VA) during amblyopia therapy of children aged 3 to 8 years occurs during the first 6 to 8 weeks . Sattler reported a VA gain in 11-year olds even during the second year of treatment . So far there are no standards concerning the intensity and duration of the treatment of patients older than 7 years of age. After a report on electronic monitoring of occlusion treatment in patients aged 7 to 16 years for 4 months , we now analyse whether this age group benefits from a longer-lasting treatment. MATERIALS AND METHODS: In this pilot study the progression of VA was analysed in 11 patients (age range 7.18 to 15.76 years; median 11.42 years) during 12 months of occlusion therapy (types of amblyopia: 5 anisometropic, 1 strabismic, 5 combined). The daily occlusion times were recorded using the occlusion dose monitor (ODM) . At the beginning of treatment the prescription of the occlusion regime (median) was 6 h/d (range 4 to 7 h/d), the (decimal) VA 0.2 (range 0.02 to 0.63) for single and 0.16 (range 0.02 to 0.8) for crowded optotypes. RESULTS: The recorded occlusion time (median) was 4.4 h/d during the 12 months of treatment, the VA gain (median) was 0.4 log units for single (range 0.2 to 0.7 log units) and 0.3 for crowded optotypes (range--0.1 to 0.6). During the period of 4 to 12 months of treatment (received occlusion 4.12 h/d) the VA gain was 0.1 log units for single and for crowded optotypes. The maximum VA gain during the interval of 4 to 12 months of treatment was 0.2 log units, both single and crowded. The interocular difference for crowded VA (median) decreased from 0.9 to 0.6 log units during treatment, however only one patient achieved an interocular difference of < 0.2 log units. CONCLUSION: The patients presented here were able to integrate daily occlusion lasting several hours and the electronic monitoring of occlusion treatment into their daily routine over a period of 12 months. During this period the VA of all included types of amblyopia improved significantly, both from a clinical and statistical point of view. Further long-term studies using ODMs with larger groups of patients may identify factors for success of treatment, reveal the long-term stability of the improvement and contribute to a standardised treatment in this age group.

Nonsurgical treatment for esotropia secondary to Arnold-Chiari I malformation: A case report.

A 14-year-old girl with diplopia and esotropia secondary to Arnold-Chiari I malformation was surgically treated with Arnold-Chiari I malformation decompression (suboccipital craniectomy), C1 and partial C2 laminectomy, and duraplasty. The residual esotropia was treated with compensatory prisms and vision therapy more than 1 year after Arnold-Chiari malformation surgery. The esotropia was resolved after approximately 3.5 months of treatment. Five years later, the patient continued to maintain fusion without compensatory prism.

Comparison of the visual effects of Fresnel prisms in normal and amblyopic eyes.

PURPOSE: To assess the effects of Fresnel prisms on visual acuity and peak contrast sensitivity in the amblyopic and sound eyes of participants with amblyopia and to determine whether these functions were affected by Fresnel prisms to a different degree than those of controls. METHODS: The LogMAR visual acuity and peak contrast sensitivity of 10 unilateral amblyopic participants (mean age, 22.6 years) and 9 controls (mean age, 26.2 years) were tested with Fresnel prisms of powers 5(Delta), 10(Delta), 15(Delta), 20(Delta), and 25(Delta) and without a Fresnel prism. RESULTS: A statistically significant reduction in visual acuity with increasing prism power was found for all 3 groups, with the visual acuity of the amblyopic eyes being the least affected by the prisms. No statistically significant differences were found between the control and the sound eyes. No statistically significant differences in the effects of the prisms on peak contrast sensitivity could be detected between the 3 groups. Fresnel prisms were found to have a smaller effect on those amblyopic eyes with a poorer baseline visual acuity, indicating that these eyes may tolerate strong prisms without substantially impairing their visual acuity. CONCLUSIONS: Fresnel prisms have a lesser effect on the visual acuity of amblyopic eyes than on controls. In contrast, results for peak contrast sensitivity were very similar for each of the groups tested, and no significant differences were evident between the amblyopic, sound, and control eyes.

Early detection of Best's disease in childhood due to ineffective orthoptic treatment.

BACKGROUND: A meticulous fundoscopy is an essential examination before administering an orthoptic occlusion therapy (patching), even in cases with a "clear indication" for patching. In this case of an 8-year-old hyperopic boy the subsequent fundoscopy revealed a bilateral maculopathy that explained the stagnation of the increase of the monocular visual acuity (VA) in spite of a correctly applied patching. HISTORY AND SIGNS: The patient was a boy (8 years old) with a history of ineffective orthoptic treatment for 15 months due to hyperopia. Complete ophthalmological examination, optical coherence tomography (Cirrus HD-OCT, Zeiss, Germany) and electro-oculography (EOG) were performed. No "everyday" symptoms were found. Best corrected VA (hyperopic) on the right was 10 / 20, on the left 8 / 20. Binocular VA was 20 / 20. 15 out of 15 Ishihara plates were identified on both sides. Orthophoria has been seen. Perimetry revealed bilateral nasal-parafoveal microscotoma. Fundoscopy showed a confined and slightly prominent yellow spot on the temporal side of the fovea. OCT revealed a subfoveal accumulation of solid material in the RPE in both eyes. EOG showed normal findings in our case. THERAPY AND OUTCOME: There was no further deterioration of VA in a follow-up time of 12 months. CONCLUSIONS: Ineffective orthoptic treatment (patching) in amblyopic children should prompt the ophthalmologist to a meticulous fundoscopy, even if done so before patching, which is highly recommended. This young patient had no "everyday" visual symptoms. Because mainly the temporal fovea on both sides was affected, he showed normal binocular VA inspite of bilateral VA reduction. The authors think that this effect is due to biretinal summation (retinal filling in).

Comparison of Harms tangent screen and search coil recordings in patients with trochlear nerve palsy.

Harms tangent screen, a subjective measurement method of three-dimensional binocular alignment, was compared with search coil recording. Twenty-three patients with unilateral trochlear nerve palsy were measured in nine gaze positions. The two methods correlated best for the horizontal gaze deviation, the vertical gaze deviation, and the vertical incomitance, but there was no correlation for the results of torsional incomitance. Using Harms tangent screen, torsional deviation underestimated the torsional incomitance measured by the search coils. Therefore, central torsional fusional mechanisms or alignment error in the Harms tangent screen are assumed.

Quantifying relative afferent pupillary defects using a Sbisa bar.

AIM: To compare the Sbisa bar (Bagolini filter bar) with neutral density filters (NDF) in quantifying relative afferent pupillary defects (RAPD). METHODS: 11 patients with a RAPD were graded and a neutral density filter bar was used to quantify the RAPD. This was repeated using the Sbisa bar. The Sbisa bar (Bagolini filter bar) is used by orthoptists to quantify density of suppression in amblyopia and is of a similar construct to NDFs. Before this clinical part of the study the luminance for each filter was measured, which enabled a direct comparison to be made. RESULTS: In the analysis of patients with RAPD a high correlation was found when comparing the Sbisa and NDF bars r = 0.95. This was statistically significant (p = <0.001). Correlation was also high when the luminance values for the filters were substituted for the clinical readings (r = 0.92; p=<0.001). CONCLUSION: The Sbisa bar is a comparable instrument to the NDF bar in measuring RAPD. Its availability in the clinical situation makes it a practical choice.

Durkan gauge and carpal compression test: accuracy and diagnostic test properties.

STUDY DESIGN: A prospective, criterion-based validity study. OBJECTIVES: To assess the diagnostic properties of the carpal compression test (CCT) when performed with the Durkan carpal tunnel syndrome (CTS) gauge, and to determine the measurement validity of the gauge. BACKGROUND: The CCT has been reported to be highly sensitive (.87-.89) and specific (.93-1.0) in the diagnosis of CTS when it is done with thumb pressure. The accuracy of measurements with the Durkan CTS gauge, however, has not been established and the diagnostic sensitivity and specificity of the CCT when the gauge is used has not been independently confirmed. METHODS AND MEASURES: The study sample included 33 women and 19 men, aged 18 to 85 years (45.7 +/- 13.5 years). The accuracy of the gauge was determined with a force dynamometer and holding frame. Standard nerve conduction studies (NCS) and the CCT were performed on the symptomatic extremity of all subjects. A compatible history and the NCS results were used to confirm CTS. RESULTS: The Durkan gauge registered pressures of 11.94 psi and 15.25 psi at the 12 and 15 psi gauge marks, respectively. Test sensitivity and specificity were .36 (95% CI = .17-.54) and .57 (95% CI = .39-.74), respectively. CONCLUSIONS: Pressure measurements obtained with the Durkan CTS gauge were accurate. The CCT when performed with the Durkan gauge, however, was neither sensitive or specific for the diagnosis of CTS.