Randot Test Research Articles

Binocular visual function improvement after pars plana vitrectomy for epiretinal membrane.

To report binocular visual function changes after pars plana vitrectomy for epiretinal membrane (ERM) and the related outcomes. Twenty-three eyes of 23 patients operated on for ERM were included in a retrospective study. Clinical data, best-corrected visual acuity (BCVA), contrast sensitivity and binocular visual function were assessed pre- and 1 and 3 months post-operatively. Binocular visual function assessment included the evaluation of fusional amplitudes (i.e., vergences) by the synoptophore, far distance stereopsis using polarized glasses and near stereopsis using Randot and TNO tests. Central macular thickness (CMT) was measured on Spectral Domain - Optical Coherence Tomography. Mean age of the patients was 67 years. Mean BCVA and contrast sensitivity significantly improved post-operatively at one (p = 0.0006 and p = 0.0022, respectively) and 3 months (p < 0.0001 and p < 0.0001, respectively), while CMT significantly decreased after 1-3 months (p < 0.0001 and p < 0.0001, respectively). Fusional amplitudes improved after 3 months (p < 0.0001). Far distance and near stereopsis significantly improved after 3 months (p < 0.0001 and p = 0.0007 for Randot test, and p < 0.0001 for TNO test, respectively). Pars plana vitrectomy for ERM surgery leads to an improvement of monocular and binocular visual functions (i.e., binocular fusion, near and far distance stereopsis), within 3 months post-operatively.

Effect of induced anisometropia on stereopsis and surgical tasks in a simulated environment

Purpose:To quantitatively correlate the loss of stereopsis by induced anisometropia with its effect on tasks that require binocular vision and stereopsis, such as ophthalmic surgery in a simulated environment.Methods:Thirty-nine ophthalmic residents with best-corrected visual acuity of 20/20 or better OU, with normal binocular vision and stereopsis, were recruited for the study. Anisometropia was induced using spherical and cylindrical trial lenses from +1D to +5D in a trial frame. The residents performed an anterior chamber navigation exercise on the EYESi simulator and the surgical score at baseline and for each level of induced anisometropia was noted. Near stereopsis was assessed by the Randot test and TNO test at baseline and for each level of induced anisometropia.Results:Stereoacuity on the Randot test and TNO test were 30 (95% CI, 25.9–34.1) and 44.4 (95% CI, 28.5–60.3) arcseconds, respectively which reduced to 65.5 (95% CI, 48.7–82.3) and 75.9 (95% CI, 15.5–136.3) arcseconds at anisometropia of +1D Sph (P < 0.001) and 380 (95% CI, 309.9–450.1) and 1922.1 (95% CI, 1582.5–2261.7) arcseconds for +5D Sph, respectively for the two tests, (P < 0.001). The corresponding surgical score reduced from 93.8 (95% CI, 91.1–96.7) to 87.5 (95% CI, 79.2–95.8, P < 0.001) for 1 DSph and 55.97 (95% CI, 38.3–73.7, P < 0.001) for 5DSph. There was a strong negative correlation between stereopsis scores and surgical task scores (Spearman's rho -0.86, P value <0.001) Similar changes were seen for anisometropia induced with cylindrical powers.Conclusion:Induced anisometropia is associated with a significant diminution in surgical task scores in a simulated environment and this is correlated with the deterioration in stereoacuity. Assessment of stereopsis may be included as a regular part of the screening procedure for ophthalmic trainee residents.

Stereo vision in air force pilots in human centrifuge during +Gz acceleration

Background/Aim. Stereo vision guarantees good vision and is one of the three main elements of binocular vision, besides simultaneous perception and fusion. It represents the third degree of binocular vision and enables estimation of distance, depth, and space between objects, i.e., allows perception of a three-dimensional image, which is crucial for a pilot. The aim of this study was to investigate the effect of +Gz acceleration on stereo vision in pilots in the air force and student pilots. Methods. Two groups of respondents were tested (30 student pilots and 65 air force pilots ? a total of 95 respondents). We considered the differences between these two groups as they provide important information about the condition of stereo vision at the beginning of the professional career and after a large number of flight hours over years of flying. We tested variations in stereoscopic vision based on the degree of acceleration of +5Gz by using the Randot Test, which enabled us to determine the degree of three-dimensional vision. Results. Temporary changes in stereo vision in student pilots were greater when compared to these changes in air force pilots when exposed to the same acceleration (+5Gz acceleration). The detailed analysis showed that the most sensitive physiological indicators were changes in stereo vision. Conclusion. We confirmed that individual physiological pilot training in a human centrifuge, where they are exposed to real G acceleration, improves tolerance to accelerations.

Impact on binocular visual function of small-incision lenticule extraction for high myopia.

To assess whether small-incision lenticule extraction (SMILE) for high myopia reduces the binocular visual function assessed by stereoacuity, binocular visual acuity, binocular contrast sensitivity, and binocular summation. University hospital. Prospective case series. Patients with a myopic spherical equivalent of at least 6.00 diopters (D) scheduled for SMILE aimed at emmetropia were included. Psychophysical testing was performed with correction preoperatively but no correction postoperatively. Stereoacuity was assessed with the Randot Circles test and the near Frisby test, visual acuity (monocular and binocular) was assessed with high-contrast Early Treatment Diabetic Retinopathy Study charts, and contrast sensitivity (monocular and binocular) was assessed with the Pelli-Robson chart and the Freiburg Acuity and Contrast Test. Binocular summation was calculated by comparing the binocular score against the best monocular score. A total of 138 eyes of 69 patients were included. The mean spherical equivalent changed from -7.46 D ± 1.06 (SD) to -0.23 D ± 0.40 postoperatively. Stereoacuity did not change significantly postoperatively; median change (interquartile range) was -0.32 (-6.21 to 1.55) seconds of arc with the Frisby test and 0.00 (-7.5 to 5.0) seconds of arc with the Randot test (P ≥ .06). Binocular postoperative uncorrected distance visual acuity was not different from the preoperative corrected distance visual acuity (P = .40). Contrast sensitivity declined slightly monocularly with both tests of contrast sensitivity but was unaltered binocularly (P ≥ .08). Binocular summation for visual acuity and contrast sensitivity was unaltered following surgery (P ≥ .09). SMILE for high myopia did not reduce the binocular function assessed by stereoacuity, binocular visual acuity, binocular contrast sensitivity, and binocular summation.

Reduced stereoacuity as a predictor for clinically significant convergence insufficiency

BackgroundStereoacuity relies on accurate binocular alignment. Convergence insufficiency (CI) a binocular motor disorder, interferes with near work.ObjectiveTo investigate the association between convergence amplitude (CA) and stereoacuity in a large paediatric...

The relationship between clinical measures of aniseikonia and stereoacuity before and after LASIK

PurposeTo determine the significance of changes and and inter-relationships between three markers of binocular function (aniseikonia, distance and near stereoacuity) following unremarkable LASIK at 3 and 6 months postoperatively. MethodsAll patients underwent LASIK using the Schwind Amaris 750S and the flaps were created using Intralase 150 kHz. Patients were I, monocular myopes II, binocular myopes III, binocular hyperopes IV, binocular astigmats V, anisometropes and VI, matched age and gender control (n = 20 in each group except III where n = 18). Aniseikonia (Awaya test), distance and near stereoacuity (Randot tests) were measured before surgery, and at 3 and 6 months after surgery. At all times data were collected under constant conditions and analyzed using appropriate non-parametric statistical tests. ResultsThe following statistically significant changes were found after applying the Bonferroni correction (p ≤ 0.001); aniseikonia reduced (groups I, III, IV, V), stereoacuity improved at distance (groups I, III-V) and near (groups I, V). Inter-group differences in aniseikonia distance and near stereoacuity were significant preoperatively, but not postoperatively. In groups I, IV and V, the changes in aniseikonia and stereoacuity (near and distance) were significantly correlated with the preoperative value. Aniseikonia was significantly correlated with distance and near stereoacuity preoperatively but not postoperatively. ConclusionBinocular function improved in all groups after LASIK except in binocular myopes. In general, binocular function was still low compared with the control group at six months postoperatively. It is unclear why binocular function improved in the binocular astigmats.

Threshold Values of Myopic Anisometropia Causing Loss of Stereopsis.

Purpose The aim of the study was to determine the threshold values of myopic anisometropia that lead to the loss of stereoacuity in most of patients. Materials and Methods Forty healthy subjects were included in the study. The inclusion criteria were as follows: lack of any functional or morphological ophthalmological disorders, or detectable damage to the visual system, anisometropia equal or less than 0.25 D in a spherical equivalent, and full stereoscopic vision for near and for distance. Myopic anisometropia was evoked by placing different focusing lenses in front of the right eye of the subject in the trial frame. Stereoscopic vision was assessed with the use of the Titmus test (dots) (Stereo Fly Test Stereo Optical Co. Inc.) for near and the Randot test for distance (Distance Randot Stereotest Stereo Optical Co. Inc.). Results The threshold values for different types of myopic anisometropia for the loss of stereopsis in more than 50% of patients were determined. For near, this value was 3 D for sphere and “against the rule astigmatism” and 4 D for “with the rule astigmatism”. For distance, the values were 2 D for sphere and “against the rule astigmatism” and 3 D for “with the rule astigmatism.” Conclusions. Myopic anisometropia of more than 2 D can cause a significant impairment of binocular vision. Stereoacuity at distance is more sensitive to myopic anisometropia than stereoacuity at near. Myopic anisometropia involving “against the rule” astigmatism potentially affects binocularity more than anisometropia with regular astigmatism. A prompt correction of anisometropia of more than 2 D is needed in children to prevent the development of amblyopia.

Binocular non-stereoscopic cues can deceive clinical tests of stereopsis

Stereoscopic vision plays a critical role in visual perception; however, it is difficult to assess. In clinical settings, stereoacuity is assessed with clinical stereotests. Observers can use monocular cues to deceive some of the most common stereotests, such as the Titmus test. The Randot test has been found free of monocular cues, and here we confirm that result by testing observers under monocular viewing. However, there is a common misconception that only monocular cues can be used to deceive stereotests. Here we demonstrate that binocular non-stereoscopic cues can also be used to pass the Randot, by testing participants with the test rotated, a condition that abolishes stereopsis, and comparing the performance to a monocular viewing condition. We also assessed the Random Dot Butterfly test and discovered considerable amounts of non-stereoscopic cues, including binocular cues in the Circles that can be used to deceive the test. Participants with amblyopia had more difficulty using non-stereoscopic cues than neurotypical observers. We gathered normal-viewing Randot stereoacuities for 110 participants (90 neurotypical and 20 with amblyopia) and compared them to psychophysical stereoacuities (our gold standard). The Randot test showed low positive normalized predictive values for detecting stereoblindness. It could perfectly detect stereo-impairment but with a low sensitivity.

Distant stereoacuity in children with anisometropic amblyopia.

To characterize changes in distant stereoacuity using Frisby-Davis Distance test (FD2) and Distant Randot test (DR) during treatment for anisometropic amblyopia, to determine factors that influence posttreatment stereoacuity and to compare the two distant stereotests. Fifty-eight anisometropic amblyopic patients with an interocular difference of ≥1.00 diopter who achieved the visual acuity 20/20 following amblyopia treatment were retrospectively included. Stereoacuity using FD2 and DR for distant and Titmus test for near measurement were assessed and compared at the initial, intermediate, and final visit. Multivariate regression models were used to identify factors associated with initial and final stereoacuity. The two distant stereotests revealed a significant improvement in distant stereoacuity after successful amblyopia treatment. Distant stereoacuity using FD2 showed the greatest improvement during the follow up period. The number of nil scores was higher in DR than FD2 at each period. In multivariate analysis, better final stereoacuity was associated with better initial amblyopic eye acuity in both distant stereotests, but not in the Titmus test. Comparing the two distant stereotests, final stereoacuity using FD2 was associated with initial stereoacuity and was moderately related with the Titmus test at each period, but final stereoacuity using DR was not. Distant stereoacuity measured with both FD2 and DR showed significant improvement when the visual acuity of the amblyopic eye achieved 20/20. Changes in distant stereoacuity by FD2 and DR during the amblyopia treatment were somewhat different.

Effect of artificial anisometropia in dominant and nondominant eyes on stereoacuity

ObjectiveTo evaluate the effect of artificial anisometropia in dominant and nondominant eyes on stereoacuity. MethodsIn this descriptive analytic study, 60 healthy adult volunteers 18–37 years of age (mean age: 25.58 years) without any ocular disease were enrolled at Tabriz Nikookari eye hospital over a 1-year period. Anisometropia (unilateral myopia) was induced by placing trial lenses over the dominant and nondominant eyes in 1-diopter (D) increments ranging from 1 to 3 D. Stereoacuity was measured using the TNO, Randot, and Titmus stereotests and values were converted into Napierian logarithm (ln) and compared between the 2 eyes. ResultsOf the 60 adults (25 male and 35 female subjects), the right eye was dominant in 49 (81.7%) of the cases. Stereoacuity levels were reduced proportionately to the degree of anisometropia in all participants. Mean stereoacuity was 4.3, 5.5, and 7.4 ln for dominant eyes and 4.1, 5.4, and 7.3 ln for nondominant eyes using the TNO test by applying 1, 2, and 3 D lenses, respectively (p > 0.05). Corresponding values were 3.5, 4.6, and 6.6 ln for dominant eyes and 3.4, 4.6, and 6.5 ln for nondominant eyes by the circles subcategory of Randot test, respectively (p > 0.05). The scores were 3.8, 4.7, and 6.5 ln for dominant eyes and 3.8, 4.7, and 6.4 ln for nondominant eyes by the circles subcategory of Titmus test, respectively (p > 0.05). ConclusionArtificial anisometropia could reduce stereoacuity. However, ocular dominance has no effect on the amount of stereoacuity reduction.

Stereopsis in end-stage renal disease (ESRD)

We investigated an effect of end-stage renal disease (ESRD) on the visual system by measuring the ability of 21 patients to perceive depth in the random dot stereograms and circles of the Randot Test. To control for other factors which might influence performance on the tests of stereopsis, patients were compared with healthy controls matched for age, years of education, IQ, and general cognitive ability. Vernier acuity (thought to reflect mainly central processing) and Landolt acuity (more sensitive to retinal and optical abnormalities) were also measured, but the study did not include a formal ophthalmological examination. All controls could perceive depth in random dot stereograms, whereas 9/21 patients could not. Patients who could perceive depth had worse stereoacuity than did their matched controls. The patient group as a whole had worse Vernier and Landolt acuities than the controls. The stereoblind patient subgroup had similar Vernier acuity to the stereoscopic subgroup, but worse Landolt acuity, and was more likely to have peripheral vascular disease. We conclude that ESRD had affected structures both within the eye, and within the visual brain. However, the similarity of Vernier acuity and difference of Landolt acuity in the stereoblind and stereoscopic patient subgroups suggest that the differences in stereoscopic ability arise from abnormalities in the eyes rather than in the brain.

Changes in stereopsis after photorefractive keratectomy

To evaluate the effects of photorefractive keratectomy (PRK) on the stereopsis of myopic and hyperopic patients. Farabi Eye Hospital, Tehran, Iran. Prospective case series. This study included patients having PRK to achieve emmetropia. The patients were divided into the following 3 groups: low myopia (<-6.0 diopters [D]), high myopia (>-6.0 D), and hyperopia (<+4.0 D). Near stereoacuity was measured using the Randot test under photopic conditions (with corrective glasses) at 40cm preoperatively (with corrective glasses) and 1, 3, and 12months postoperatively. Repeated-measure analysis of variance was used to assess changes in stereopsis over time in the 3 groups. Each group comprised 60 patients. The mean preoperative stereoacuity was 121.16seconds of arc (arcsec)±149.92 (SD), improving to 83.66±75.84 arcsec 1month postoperatively and 80.66±64.31 arcsec at 3months (both P<.001). It remained unchanged (83.33±75.01 arcsec) at 12months (P=.610). Patients with high myopia had the greatest improvement in stereopsis after PRK compared with low myopic and hyperopic patients (P<.001). The improvement in stereoacuity was significantly higher in the severe anisometropic group; the lowest improvement was in the group without anisometropia. Photorefractive keratectomy could result in an improvement in stereopsis. Patients with high myopia benefitted most from PRK in terms of improvement in stereopsis. None of the authors has a financial or proprietary interest in any material or method mentioned.

Depth Perception and Grasp in Central Field Loss.

PurposeWe set out to determine whether individuals with central field loss benefit from using two eyes to perform a grasping task. Specifically, we tested the hypothesis that this advantage is correlated with coarse stereopsis, in addition to binocular summation indices of visual acuity, contrast sensitivity, and binocular visual field.MethodsSixteen participants with macular degeneration and nine age-matched controls placed pegs on a pegboard, while their eye and hand movements were recorded. Importantly, the pegboard was placed near eye height, to minimize the contribution of monocular cues to peg position. All participants performed this task binocularly and monocularly. Before the experiment, we performed microperimetry to determine the profile of field loss in each eye and the locations of eccentric fixation (if applicable). In addition, we measured both acuity and contrast sensitivity monocularly and binocularly, and stereopsis by using both a RanDot test and a custom stereo test.ResultsPeg-placement time was significantly shorter and participants made significantly fewer errors with binocular than with monocular viewing in both the patient and control groups. Among participants with measurable stereopsis, binocular advantage in peg-placement time was significantly correlated with stereoacuity (ρ = −0.78; P = 0.003). In patients without measurable stereopsis, the binocular advantage was related significantly to the overlap in the scotoma between the two eyes (ρ = −0.81; P = 0.032).ConclusionsThe high correlation between grasp performance and stereoacuity indicates that coarse stereopsis may benefit tasks of daily living for individuals with central field loss.

근거리 입체시와 사위 및 굴절이상의 상관관계

목적: 본 연구는 성인 남녀의 근거리 입체시와 근거리 사위의 관계를 알아보고, 근거리 입체시와 사위 및 굴절이상과의 상관성을 조사하였다. 방법: 성인 83명(남자 36명, 여자 47명, 평균 연령 <TEX>$21.09{\pm}1.74$</TEX>(19~29)세)을 대상으로 굴절이상자는 완전교정 후, 검사거리 40 cm에서 근거리 입체시는 Titmus-fly Stereotest(Stereo Optical Co., Inc., Chicago, IL, USA)와 RANDOT Stereotest(Stereo Optical Co., Inc., Chicago, IL, USA), 사위는 수정토링톤법(modified torrington method)으로 측정하였다. 결과: 근거리 입체시는 남자가 여자보다 더 좋았고 남녀 간에 차이는 없었으나, 근거리 사위는 여자가 남자보다 더 높았으며 남녀 간에 유의한 차이가 있었다(p<0.05). 근거리 입체시는 Titmus-fly Stereotest와 RANDOT Stereotest 결과 각각 내사위에서 <TEX>$262.17{\pm}562.43$</TEX>초, <TEX>$243.08{\pm}68.04$</TEX>초, 정위에서 <TEX>$148.42{\pm}269.54$</TEX>초, <TEX>$107.40{\pm}263.74$</TEX>초, 외사위에서 <TEX>$113.94{\pm}152.46$</TEX>초, <TEX>$79.70{\pm}136.83$</TEX>초로 사위 세 그룹 간에는 차이가 없었으나(p>0.05), 내사위와 근거리 입체시는 높은 상관성이 있었다(r=0.68). 또한 근거리 입체시가 굴절이상에서는 각각 정시에서 <TEX>$80.00{\pm}571.43$</TEX>초, <TEX>$68.75{\pm}36.82$</TEX>초, 근시에서 <TEX>$133.57{\pm}224.15$</TEX>초, <TEX>$93.14{\pm}214.95$</TEX>초 원시에서 <TEX>$511.20{\pm}855.00$</TEX>초, <TEX>$511.4{\pm}855.60$</TEX>초로 세 그룹 간에 유의한 차이를 나타냈다(p<0.05). 근거리 입체시를 굴절이상도로 분류했을 때, 정시에서 가장 좋고 고도 근시, 고도원시로 굴절이상도가 높았을 때 감소하였다. 결론: Titmus-fly Stereotest와 RANDOT Stereotest 결과, 성인의 근거리 입체시는 내사위일 때, 굴절이상이 높을 때 감소되어 사위 및 굴절이상과 관계가 있었고, 이 두 입체시 검사에서 근거리 입체시가 나쁠 경우에 사위 또는 굴절이상을 예상할 수 있다. Purpose: This study was investigated the relationship between the male and female of near stereoacuity and phoria, and was examined the correlations between near stereoacuity and phoria and refractive error. Methods: Adult 83 (male 36, female 47, mean age <TEX>$21.09{\pm}1.74$</TEX>(19~29) years old) target was examined after full correction of refractive error. Near stereoacuity was measured by using Titmus-fly Stereotest(Stereo Optical Co., Inc., Chicago, IL, USA), and RANDOT Stereotest (Stereo Optical Co., Inc., Chicago, IL, USA), phoria was measured by using modified torrington method, at distance 40 cm. Results: In near stereoacuity, male was better good than female, and there was no difference between male and female (p>0.05). In near phoria, female was more higher than male, and there was a significant difference between male and female (p<0.05). Near stereoacuity by Titmus-fly test and Randot test result respectively was <TEX>$262.17{\pm}562.43$</TEX> sec (second of arc) <TEX>$243.08{\pm}68.04$</TEX> sec in esophoria, <TEX>$148.42{\pm}269.54$</TEX> sec, <TEX>$107.40{\pm}263.74$</TEX> sec in orthophoria, <TEX>$113.94{\pm}152.46$</TEX> sec, <TEX>$79.70{\pm}136.83$</TEX> sec in exophoria, there was a no difference between three phoria groups (p>0.05), and was a high correlation between phoria and near stereoacity(r=0.68). In addition, near stereoacuity in the refractive error respectively was <TEX>$80.00{\pm}571.43$</TEX> sec, <TEX>$68.75{\pm}36.82$</TEX> sec in myopia, <TEX>$133.57{\pm}224.15$</TEX> sec, <TEX>$93.14{\pm}214.95$</TEX> sec in hyperopia, <TEX>$511.20{\pm}855.00$</TEX> sec, <TEX>$511.4{\pm}855.60$</TEX> sec, there was a significant difference between three phoria groups (p<0.05). when was classfiied near stersoacuity into degree of refractive error, near stersoacuity was best in emmetropia, and was reduced when refractive error was highest in high degree myopia, and hyperopia. Conclusions: Titmus-fly Stereotest and RANDOT Stereotest result, near stereoacuity of adults, when esophoria and high degree refractive error, was reduced, there was a relationship between near stereoacuity with phoria, and refractive error. In this both stereotests if was bad when near stereoacuity can expect a phoria and refractive error.

New stereoacuity test using a 3-dimensional display system in children.

The previously developed 3-dimensional (3D) display stereoacuity tests were validated only at distance. We developed a new stereoacuity test using a 3D display that works both at near and distance and evaluated its validity in children with and without strabismus. Sixty children (age range, 6 to 18 years) with variable ranges of stereoacuity were included. Side-by-side randot images of 4 different simple objects (star, circle, rectangle, and triangle) with a wide range of crossed horizontal disparities (3000 to 20 arcsec) were randomly displayed on a 3D monitor with MATLAB (Matworks, Inc., Natick, MA, USA) and were presented to subjects wearing shutter glasses at 0.5 m and 3 m. The 3D image was located in front of (conventional) or behind (proposed) the background image on the 3D monitor. The results with the new 3D stereotest (conventional and proposed) were compared with those of the near and distance Randot stereotests. At near, the Bland-Altman plots of the conventional and proposed 3D stereotest did not show significant difference, both of which were poorer than the Randot test. At distance, the results of the proposed 3D stereotest were similar to the Randot test, but the conventional 3D stereotest results were better than those of the other two tests. The results of the proposed 3D stereotest and Randot stereotest were identical in 83.3% at near and 88.3% at distance. More than 95% of subjects showed concordance within 2 grades between the 2 tests at both near and distance. In conclusion, the newly proposed 3D stereotest shows good concordance with the Randot stereotests in children with and without strabismus.

The Binocular Advantage in Visuomotor Tasks Involving Tools

We compared performance on three manual-dexterity tasks under monocular and binocular viewing. The tasks were the standard Morrisby Fine Dexterity Test, using forceps to manipulate the items, a modified version of the Morrisby test using fingers, and a “buzz-wire” task in which subjects had to guide a wire hoop around a 3D track without bringing the hoop into contact with the track. In all three tasks, performance was better for binocular viewing. The extent of the binocular advantage in individuals did not correlate significantly with their stereoacuity measured on the Randot test. However, the extent of the binocular advantage depended strongly on the task. It was weak when fingers were used on the Morrisby task, stronger with forceps, and extremely strong on the buzz-wire task (fivefold increase in error rate with monocular viewing). We suggest that the 3D buzz-wire game is particularly suitable for assessing binocularly based dexterity.

Stability of near stereoacuity in childhood intermittent exotropia

To investigate the course of near stereoacuity in a cohort of children with untreated intermittent exotropia. A total of 95 children ages 2-16 years with untreated intermittent exotropia were identified who had measurements of near stereoacuity using the Preschool Randot (PSR) test on at least 2 successive examinations, with no intervening treatment. Deterioration was defined as a drop of at least 3 octaves, as determined by test-retest data. Alternative secondary analyses were performed defining deterioration as a drop of at least 2 octaves or as a transition from normal to subnormal. The main outcome measure was the deterioration rate calculated at 1 and 2 years using a Kaplan-Meier survival analysis. For near stereoacuity, the rate of decreasing 3 or more octaves was 2% (95% CI, 0%-6%) at 1 year and 7% (95% CI, 0%-16%) at 2 years. The alternative secondary analyses revealed similar low deterioration rates. In most cases of apparent deterioration, near stereoacuity returned to baseline levels without treatment. For children with untreated intermittent exotropia, deterioration in near stereoacuity at 1 and 2 years is infrequent. Therefore, performing surgery for intermittent exotropia to proactively prevent deterioration of near stereoacuity cannot be justified. Retesting stereoacuity is critical to determine whether any measured decrease in stereoacuity is real.

Horizontal lang two-pencil test as a screening test for stereopsis and binocularity

Purpose:To assess the horizontal Lang two-pencil test as a bedside test to detect gross stereopsis.Materials and Methods:Eighty-four strabismic subjects divided into two groups based on the amount of deviation, and 40 normal subjects were studied. Sensory status examination including binocularity and stereopsis were evaluated with Bagolini, Titmus test and the Netherlands organisation for applied scientific research (TNO), Randot, synoptophore and horizontal Lang two-pencil test.Results:The subjects in the group with smaller deviation showed better performance on all the four stereo tests and over 90% demonstrated presence of fusion. When compared to TNO and Randot for determining presence of stereopsis, the horizontal Lang two-pencil test demonstrated sensitivity of 100% and 83.9%, specificity of 77.8% and 73.7%, and negative predictive value of 100% and 100% respectively. It also showed 100% specificity as a test for binocularity when compared with the Bagolini striated glass test.Conclusion:Horizontal Lang two-pencil test, an easily performed test with a high sensitivity and negative predictive value can be used as a screening test to detect gross stereopsis and binocularity.

Variability of Stereoacuity in Intermittent Exotropia

Distance stereoacuity is used to monitor deterioration of intermittent exotropia (IXT), but variability of stereoacuity has not been studied rigorously. The purpose of this study was to assess the variability of stereoacuity over one day in children with IXT. Prospective cohort study. Twelve children with IXT were recruited. Stereoacuity was assessed using the Frisby Davis Distance test and the Distance Randot test at distance, and the Frisby and Preschool Randot tests at near. Tests were repeated three or four times over the day, with at least two hours between assessments. The main outcome measure was variable stereoacuity defined as a change by two or more log levels between any two time points over the day. Variable stereoacuity at distance was found in five (42%) of 12 patients. Four (33%) of 12 patients demonstrated variable results using the Distance Randot test, three of whom also showed variable results using the Frisby Davis Distance test. One patient had variable results using the Frisby Davis Distance test only. Nine (75%) of 12 patients completed near stereoacuity testing; two (22%) of nine showed variable near stereoacuity. Two (22%) of nine showed variable results using the Preschool Randot test, one (11%) of whom also had variable results using the Frisby test. In some cases, stereoacuity changed from measurable stereoacuity on one assessment to nil on another. Nearly half of children with IXT show marked changes in stereoacuity over the course of a single day. When based on isolated measures, an apparent change in distance stereoacuity between visits should be interpreted with caution.

Improvement in distance stereoacuity following surgery for intermittent exotropia

To evaluate whether distance stereoacuity improves following surgery for intermittent exotropia using the Frisby Davis Distance (FD2) and Distance Randot stereotests. Eighteen patients (median age, 24 years; range, 5 to 68 years) with intermittent exotropia were prospectively enrolled. Stereoacuity was measured pre- and 6 weeks postoperatively using the FD2 and Frisby near tests (real depth tests) and Preschool Randot and Distance Randot tests (polaroid vectographs). Distance stereoacuity measured with the FD2 improved from a median preoperative value of 80 to 40 arcsec postoperatively (p = 0.04) and stereoacuity measured with the Distance Randot improved from a median of nil to 200 arcsec (p = 0.06). In those that had subnormal stereoacuity preoperatively, there was even more marked improvement in distance stereoacuity (FD2 median nil vs 40 arcsec, p = 0.002; Distance Randot median nil vs 200 arcsec, p = 0.004). Near stereoacuity measured with Frisby and Preschool Randot remained unchanged pre- to postoperatively (median, 60 and 80 arcsec, respectively). There was improvement in distance stereoacuity measured with both the FD2 and the Distance Randot stereotests in patients who underwent surgery for intermittent exotropia. The FD2 and Distance Randot may be useful outcome measures in future clinical trials of interventions for intermittent exotropia.