TNO Stereotest Research Articles

Preoperative aniseikonia is a prognostic factor for postoperative stereopsis in patients with unilateral epiretinal membrane.

To investigate stereopsis and other visual functions in patients with unilateral epiretinal membrane (ERM) and to identify vision-related parameters affecting stereopsis. This prospective study included 63 consecutive patients who were scheduled to undergo vitrectomy for unilateral idiopathic ERM. We examined stereopsis (Titmus Stereo Test, TST; TNO stereotest, TNO), best-corrected visual acuity (BCVA), letter contrast sensitivity, severity of metamorphopsia, and degree of aniseikonia preoperatively and 6months postoperatively. Preoperatively, we observed significant correlation between TST scores and other vision-related parameters except severity of metamorphopsia and between TNO score and all the vision-related parameters. Multiple regression analysis showed that preoperative TST and TNO scores were significantly associated with the degree of aniseikonia (both P < 0.01). ERM surgery significantly improved stereopsis, BCVA, contrast sensitivity, and metamorphopsia, but not aniseikonia. Postoperatively, TST was significantly associated with BCVA, and TNO showed association with BCVA and aniseikonia. Postoperative TST and TNO scores showed significant correlation with preoperative aniseikonia (P < 0.005 and P < 0.001, respectively). Impairment of stereopsis in patients with unilateral ERM was considered to be due to retinally induced aniseikonia. Aniseikonia did not improve by surgery, and preoperative aniseikonia can be a prognostic factor for postoperative stereopsis.

Vision-related parameters that affect stereopsis in patients with macular hole

This study evaluated stereopsis and other visual functions in patients with idiopathic macular hole (MH), and sought to identify vision-related parameters that affect stereopsis. In this prospective, consecutive, comparative study, 39 eyes of 39 patients with unilateral idiopathic MH were included. At baseline and at 6 months after MH surgery, we evaluated stereopsis, with the Titmus stereo test (TST) and TNO stereotest (TNO), best-corrected visual acuity (BCVA), letter contrast sensitivity, severity of metamorphopsia, as assessed using M-CHARTS, and extent of aniseikonia, by the new aniseikonia test. Preoperative stereopsis (log) in patients with MH were 2.72 ± 0.53 (range 1.9–4.1) in the TST and 2.82 ± 0.65 (range 1.8–3.9) in the TNO. Preoperative TST was significantly correlated with letter contrast sensitivity (p < 0.05), but not with the other visual functions. TNO showed significant correlation with letter contrast sensitivity (p < 0.05) and aniseikonia (p < 0.005). Preoperative TNO was associated with aniseikonia by multivariate analysis (p < 0.005). MH surgery significantly improved stereopsis, BCVA, letter contrast sensitivity, metamorphopsia, and aniseikonia. Postoperative TST and TNO was significantly associated with BCVA by multivariate analysis. Deterioration of stereopsis in MH patients is associated with contrast sensitivity and the degree of aniseikonia.

SENSORY OUTCOME AFTER SURGERY FOR INTERMITTENT EXOTROPIA

Purpose: To investigate whether patients with intermittent exotropia can achieve better postoperative sensory outcome, including improvement in the stereo-acuity and increase in thegrade of binocular single vision. Methods: 20 patients diagnosed as intermittent exotropia whounderwent surgery, motor changes measured with an alternate cover test and Simultaneousprism and cover test and Assessment of sensory changes by Worth's 4 dot test used to assessfusion for near and far and Stereoacuity measurements performed using global TNO test.Results: Males were 11 in numbers (55%) while females were 9 (45%). age ranges from 5-27years. Range of BCVA was (0.2-1). Mean + S.D = 0.8 + 0.223. 16 out of 20 patients achievedorthotropia postoperative, while there was 2 patients with overcorrection and 2 patients withunder correction. W4D for far shows significant improvement p=0.99 while W4D for near showsInsignificant improvement p=0.223. TNO stereotest: 16 out of 20 patients could pass the test,only four patients couldn't pass it completely pre-op. Conclusions: Impairment of BSV in (x)t isusually in the form of suppression. The most severe binocular impairment is monofixatonsyndrome with loss of all central binocular vision & development of central scotoma,Stereoacuity is diminished but in a mild form. It can return to normal levels in many patients byappropriate surgery.

Investigation of relationship between colour discrimination ability and stereoscopic acuity using Farnsworth Munsell 100 hue test and stereo tests

ObjectiveTo evaluate the effect of colour discrimination ability on the stereoscopic acuity by comparing individuals having congenital colour vision deficiency (CCVD) with healthy individuals. DesignA comparative study. ParticipantsThe study included 53 binocular males, of whom 26 (mean age, 36.04 ± 9.30 years) were in the healthy group and 27 (mean age, 33.04 ± 9.81 years) were in the CCVD group. MethodsThe following tests were used: the Ishihara pseudo-isochromatic plate test for detecting CCVD, the Farnsworth Munsell 100 (FM100) hue test for colour discrimination ability, the TNO and Titmus stereo tests for stereoscopic acuity. ResultsIn the CCVD group, 20 males were deutan and 7 males were protan. According to the FM100 hue test, total error score (TES), blue/yellow (b/y) local error score (LES), and red/green LES were significantly lower in the healthy group (30.23 ± 18.78, 15.15 ± 10.38, and 13.88 ± 11.93, respectively) than in the CCVD group (133.59 ± 67.45, 41.15 ± 22.03, and 89.15 ± 52.16, respectively) (p < 0.01 for each). The stereo test scores revealed significantly higher stereoscopic acuity in the healthy group (43.85 ± 33.92 arcsec for the TNO test and 40.00 ± 0.00 arcsec for the Titmus test) than in the CCVD group (93.33 ± 90.51 arcsec for TNO stereo test and 52.96 ± 24.62 arcsec for the Titmus test) (p < 0.05 for each). The TNO test score was significantly and positively correlated with the TES (r = 0.390, p = 0.049) and b/y LES (r = 0.490, p = 0.011) in the healthy group. ConclusionsColour discrimination ability affected stereoscopic acuity. Moreover, stereoscopic acuity increased with increasing colour discrimination ability, which could be originated from the b/y colour region.

Abnormal stereopsis and reduced retinal sensitivity in patients with retinitis pigmentosa

The aim of the study was to evaluate retinal sensitivity and stereoacuity (SA) in retinitis pigmentosa (RP) patients. Twenty-six patients with RP were examined, mean age 36.4 ± 7.21 (SD)years old and best corrected visual acuity better than 0.15 logMAR. The control group (CG) included 25 healthy subjects matching the RP group by age and sex. Every patient and healthy control underwent a complete ophthalmologic examination: Titmus, Lang, TNO stereotests and microperimetry (MP-1) (Nidek Technologies). Results were subjected to factor analysis using Varimax rotation, and p values < 0.05 were considered statistically significant. With the Titmus stereotest, the mean SA was 136.52 ± 26.5(SD)arcsec in the RP group and 67.2 ± 11.5(SD) in CG; Lang SA was 391.39 ± 53.72(SD) in RP group and 1150 ± 33.4(SD) in CG; and TNO SA was 69.3 ± 14.39(SD) in the RP group and 15.97 ± 3.7(SD) in CG. Factor analysis showed significant correlation between visual acuity and SA (p = 0.0001) in RP group. MP-1 demonstrated that in RP patients, inter-ocular difference in retinal sensitivity and fixation stability was related to anomalous stereopsis (p values < 0.05). Progressive RP degeneration in the cone system could determine a significant impairment in the binocular vision due to anomalous inter-ocular retinal sensitivity and incomplete Panum's area utilization, causing an incongruent retinal localization. These findings suggest a possible reason why RP patients with a central retinal involvement, even if minimal, perceive a damaged stereoscopic perception that produces a severe disability.

Comparative analysis of the Lang Stereopad in a non-clinic population

ABSTRACTAim: New methods of measurement require testing to evaluate test validity. This study compares stereoacuity results of the Lang Stereopad to other common clinical stereoacuity assessments in a normal vision population.Methods: A prospective cross-sectional study was conducted comparing the Lang Stereopad stereoacuity results to results from the Lang II, Frisby, and TNO stereo tests. Mean stereoacuity values and their correlation with inter-ocular visual acuity difference were compared for each stereo test.Results: 98 subjects (mean age of 33.5 years, SD 14.1; 39 males and 59 females) with normal parameters of visual function underwent multiple stereotest assessments. Median stereoacuity values were the lowest (i.e. more detailed stereoacuity) when using the Frisby stereotest (median 40”; 20–170” [minimum-maximum]) and TNO stereotest (median 60”; 15–480”). In comparison, medians were about double at 100” (50–800”) for the Lang Stereopad and greater at 200” (200–200”) for the Lang II stereotest. There was no correlation for each stereotest with interocular visual acuity differences.Conclusions: The Lang Stereopad test is easy to administer and it has certain advantages such as no requirement for additional test glasses. It is a useful assessment to add to the clinical armamentarium for binocular assessment of stereopsis. The Lang Stereopad does not agree well with other stereo tests such as the TNO and Frisby but provides a greater stereoacuity test range than the Lang II. The Lang Stereopad now requires testing in a clinical population in which stereoacuity is a pre-requisite part of the assessment.

The Effects of Anisometropic Amblyopia on the FNS and TNO Stereotest Thresholds in Four- to Eight-Year-Olds.

Purpose:To investigate the relationship between stereoacuity and factors associated with anisometropic amblyopia in children aged 4–8 years.Methods:44 participants had their stereoacuity thresholds measured using the Frisby Near Stereotest (FNS) and the TNO Randot Stereotest (TNO). Participants were divided into anisometropic amblyopes and controls (normal uniocular visual acuity (VA) with or without glasses). FNS and TNO stereoacuity thresholds were compared based on different factors, which included interocular acuity difference (IAD), VA levels, and the degree of anisometropia.Results:All 44 participants achieved better stereoacuity with the FNS compared to the TNO (p = 0.045). The control group performed significantly better on the FNS (p = 0.012) and the TNO (p = 0.009) when compared with anisometropic amblyopes. The only statistically significant correlation was found between stereoacuity – as measured with FNS – and IAD (p = 0.009). However, the TNO showed a correlation in the presence of poor VA, larger IADs and a high degree of anisometropia.Conclusions:Stereoacuity thresholds are significantly affected by poor VA, large IAD and high degrees of spherical anisometropia when trying to distinguish the resolution of a target with the TNO yet the same factors do not appear to affect ability to distinguish the disparity of a target with the FNS. Controls also performed worse on the TNO.

Stereopsis after Intravitreal Ranibizumab Injections for Branch Retinal Vein Occlusion

To evaluate stereopsis before and after intravitreal ranibizumab (IVR) injections in patients with branch retinal vein occlusion (BRVO) and investigate the relationship between stereopsis and retinal microstructure. Prospective, observational, controlled study. Thirty-two eyes of 32 patients undergoing IVR treatment for BRVO and 28 eyes of age-matched healthy control participants. Stereopsis was measured using the Titmus stereo test (TST) and TNO stereo test before and 1, 2, 3, 4, 5, and 6 months after treatment. Stereopsis, best-corrected visual acuity (BCVA), duration of disease, central retinal thickness, status of the external limiting membrane, ellipsoid zone, and external limiting membrane, and serous retinal detachment (SRD) after treatment. Treatment with IVR significantly improved the TST (P < 0.001) and TNO stereo test (P < 0.05) scores as well as BCVA (P < 0.001) and central retinal thickness (P < 0.005). Stereopsis after IVR injection in eyes with BRVO was significantly worse than that in healthy control participants (TST, P < 0.001; TNO stereo test, P < 0.001). The TST and TNO stereo test scores were correlated significantly with BCVA and the presence of SRD at baseline. After 6 months of treatment, an association of TST and TNO stereo test scores with BCVA and status of the external limiting membrane and ellipsoid zone was observed. Stereopsis after treatment showed a significant relationship with BCVA and presence of SRD at baseline. Administration of IVR for BRVO improved early stereopsis, albeit not to a normal level. Presence of SRD and visual acuity were predictors of stereopsis after treatment in patients with BRVO.

Comparison of the Effect of Different Types of Experimental Anisometropia on Stereopsis Measured with Titmus, Randot and TNO Stereotests.

Purpose:To assess the effect of experimental anisometropia and monovision on stereopsis using the Titmus, Randot, and TNO stereoacuity tests.Methods:Sixty adult volunteers were enrolled in the present study. Four different types of anisometropia—myopia, hyperopia, and astigmatism (both 90° and 45°)—were induced by placing trial lenses over the dominant eye (from 3 to 1 D). Stereoacuity was measured using the Titmus, Randot, and TNO tests.Results:In all the anisometropia types, stereopsis deteriorated with increase in anisometropia in the three stereoacuity tests performed (P < 0.001). The largest decrease in stereopsis was attributed to 3 D myopic anisometropia—6.51 ± 2.10, 6.59 ± 2.35, and 7.36 ± 1.89 arc seconds in Titmus circles, Randot circles, and TNO, respectively. Minimal change in stereopsis was observed in 1 D astigmatism of 45°.Conclusion:Any type of anisometropia may reduce stereoacuity; this reduction is most noticeable with myopic anisometropia, especially in the TNO test, probably due to the lack of monocular cues.

Statistics of TNO stereotest for the diagnosis of microesotropia in children.

To analyze statistically the real effectiveness of TNO stereotest for the diagnosis of microesotropia in young patients in daily practice. We considered 312 patients whose age ranged from 3 to 18 years (mean age 7.5 years) suspected to be microesotropic. All underwent a full orthoptic and ophthalmologic examination. The TNO stereotest was presented at a distance of 40 cm with the patient wearing red-green glasses. The Paliaga 8-D base-in test was considered the gold standard diagnostic test to detect microesotropia. The specificity of the TNO stereotest from the collected data was 98%, the sensitivity 94%, the positive predictive value 80%, the negative predictive value 99%, and the likelihood ratio 47. It is important to use the TNO stereotest in clinical daily practice to detect microesotropia, but considering some bias: the age of the young patients, the difficulties encountered in understanding some figures, and the presence of a stereoscopic status even in microtropic subjects.

Overestimation of stereo thresholds by the TNO stereotest is not due to global stereopsis.

PurposeIt has been repeatedly shown that the TNO stereotest overestimates stereo threshold compared to other clinical stereotests. In the current study, we test whether this overestimation can be attributed to a distinction between ‘global’ (or ‘cyclopean’) and ‘local’ (feature or contour‐based) stereopsis.MethodsWe compared stereo thresholds of a global (TNO) and a local clinical stereotest (Randot Circles). In addition, a global and a local psychophysical stereotest were added to the design. One hundred and forty‐nine children between 4 and 16 years old were included in the study.ResultsStereo threshold estimates with TNO were a factor of two higher than with any of the other stereotests. No significant differences were found between the other tests. Bland‐Altman analyses also indicated low agreement between TNO and the other stereotests, especially for higher stereo threshold estimates. Simulations indicated that the TNO test protocol and test disparities can account for part of this effect.DiscussionThe results indicate that the global – local distinction is an unlikely explanation for the overestimated thresholds of TNO. Test protocol and disparities are one contributing factor. Potential additional factors include the nature of the task (TNO requires depth discrimination rather than detection) and the use of anaglyph red/green 3D glasses rather than polarizing filters, which may reduce binocular fusion.

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.

Acute acquired concomitant esotropia and decompensated monofixation syndrome: a sensory-motor status assessment

ObjectiveTo assess and compare sensory-motor status and clinical features of type I and type II acute acquired concomitant esotropia (group A) and decompensated monofixation syndrome (group B). MethodsIn a retrospective, comparative study, 26 patients with a confirmed postoperative diagnosis of type I and II acute acquired concomitant esotropia and monofixation syndrome were enrolled. The 2-tailed unpaired t test and 2-tailed χ2 test were performed to compare angle of deviation and sensory-motor status under the environmental conditions and after prismatic adaptation test and progressive prism test of 2 groups. ResultsAll of the patients of group A and 4 patients (33%) of group B experienced diplopia under viewing conditions in the Worth’s 4 dot and Bagolini striated glass tests. The TNO stereo test showed the total absence of stereopsis in 6 patients in group B and a significantly lower stereoacuity in group A in the remaining 6 patients (p < 0.0001). The prismatic adaptation test was positive in all of the patients in group B and in 10 patients (71%) in group A (p = 0.39). The value of the angle of deviation after the progressive prism test was significantly higher in group B than in group A (p = 0.02). At the end of the progressive prism test, all of the patients in group A and only 2 patients in group B were orthotropic (p = 0.01). ConclusionsBagolini striated glass and Worth’s 4 dot tests under viewing conditions and responses under prisms allow for the differentiation of the 2 forms and lead to an accurate aesthetic and functional prognosis.

Vision Screening in Zurich

In the city of Zurich, vision screening is performed by school medical services as part of the legally compulsory preventive medical examinations. We retrospectively evaluated the results of the 2011-2012 school year. Preventive medical examinations by the school medical services were performed in all kindergartens. The examinations were mandatory for first, second and eighth grade children, whilst those for the fourth grade were voluntary. The basic diagnostic testing consisted of monocular visual acuity (Snellen E chart) for all age groups and the stereopsis test (TNO test) in kindergartens. Vision screening was performed on 7499 children. 1471 first graders (55 %), 201 fourth graders (11 %) and 211 eighth graders (12.3 %) did not pass the examinations. In 33.7 % of the children who underwent the follow-up examination from an ophthalmologist, amblyogenic potential was found. Vision screening by the school medical services enrols most of the children from a single age group. The Snellen E charts used for the monocular distance acuity, together with the TNO stereo test, appear to constitute an effective testing combination. Ophthalmological follow-up examinations of the affected children revealed that one third were afflicted by amblyogenic factors.

Predictors of stereoacuity outcome in visually mature subjects with exotropia.

The purpose of this study was to determine the predictors of stereoacuity outcome in visually mature subjects with exotropia following surgical correction. Visually mature subjects who were surgically aligned and had been tested for stereoacuity in the postoperative period were studied retrospectively. Subjects were grouped with respect to their responses to Titmus or TNO stereotests. Characteristics such as amblyopia, anisometropia, and characteristics of the exodeviation such as time of onset, duration, intermittency, presence of an A or V pattern, distance-near disparity, coexisting vertical deviation, and inferior oblique overaction, were compared between the groups. One hundred and four visually mature subjects with exotropia met the inclusion criteria. Stereoacuity was achieved in 77% of the study group and only 9% of these could achieve fine stereoacuity. Negative stereoacuity was more frequently associated with larger deviation angles, higher anisometropia, inferior oblique overaction, pattern strabismus, coexisting vertical strabismus, and distance-near disparity, but not at a statistically significant level. The optimal cutoff for strabismus duration was 20 years for a positive stereoacuity outcome. Any-level visual acuity difference was found to decrease the chance for positive stereoacuity significantly. The odds ratios for the stereoacuity positivity were 4.05 for strabismus duration <20 years, 7.9 for strabismus onset >1 year of age, 3.79 for weaker eye visual acuity >20/25 and 9.85 for intermittency of strabismus. Intermittence of exotropia was the strongest predictor for positive stereoacuity. Exotropia onset after 1 year of age, absence of any-level visual acuity difference, and strabismus duration <20 years were the other predictors with decreasing power.

Factors Affecting Improvement of Stereopsis Following Successful Surgical Correction of Childhood Strabismus in Adults

ABSTRACTPurpose: To evaluate the factors affecting improvement of stereopsis following successful surgical correction of childhood strabismus in adults.Methods: In a prospective study, consecutive patients with childhood-onset, comitant, horizontal, constant strabismus; stereoacuity of more than 480 seconds of arc in TNO stereo test (absent stereopsis in TNO); and who had successful postoperative alignment (within 10 prism diopters [PD] of orthotropia) were enrolled. Postoperative stereopsis testing was performed using the TNO stereo test at 3 months after surgery.Results: A total of 34 patients (20 exotropes and 14 esotropes) were included. The mean age at the time of surgery was 26.08 ± 10.53 years (range, 14–53 years). Stereopsis was improved in 8 of 34 patients (23.5%). Postoperative alignment had influence on improvement of stereopsis; 38.1% of patients who had orthotropia gained stereopsis, whereas none of patients who had horizontal heterotropia (esotropia or exotropia) of 10 PD or less gained stereopsis (p = 0.01). Misalignment of 10 years’ duration or longer did not preclude the development of postoperative stereoacuity (p = 0.31). There was a statistically insignificant increase in improvement of stereopsis in nonamblyopic group (30.4%) compared with amblyopic group (9.1%) (p = 0.22). Also, there was a statistically insignificant increase in improvement of stereopsis in exotropes (35%) compared with esotropes (7.1%) (p = 0.1). The angle of preoperative deviation had no influence on improvement of stereopsis (p = 0.44).Conclusion: A postoperative correction of orthotropia was the only predictive factor for improvement of stereopsis in adults with childhood strabismus.

The influence of a prolonged interoperative period on binocular vision after bilateral cataract extractions.

To evaluate the influence of the extent of the interoperative period on binocular vision function in patients after consecutive bilateral cataract extractions and intraocular lens implantation. The study included patients operated due to bilateral cataract. Presence of asthenopic symptoms, distance and near squint angle, fusional amplitudes, stereopsis, and convergence were evaluated. Preoperative, interoperative, and postoperative differences in best-corrected visual acuity between eyes were also noted. Multivariate analysis was conducted in order to establish the relation between the interoperative period and binocular status. The study included 104 patients (74 female, 30 male, mean age 69.9 years, range 32-88). Mean interoperative period was 20.3 ± 12.9 months, range 1.5-47.7. Prolongation of the interoperative interval had a significant negative impact on stereopsis measured by TNO (R2 = 0.215, p = 0.001) and Randot (R2 = 0.179, p = 0.001) stereotests, as well as for near point of convergence (R2 = 0.09, p = 0.002). It was also related, but not independently, to reduction in fusional amplitudes, mainly for distance (R2 = 0.18, p = 0.001 for divergence and R2 = 0.12, p = 0.001 for convergence). Asthenopic symptoms were reported by 17 (16.3%) patients. The incidence of exophoria was significantly (p = 0.002) higher in patients with an interoperative interval longer than 24 months. The length of the interoperative period influences the status of binocular vision in patients after bilateral cataract extraction. It is also connected with an increased number of patients with asthenopic symptoms and exophoria.

Correlation between Depth Perception by Three-Rods Test and Stereoacuity by Distance Randot Stereotest

Background: The examination of depth perception with three-rods test, in addition to visual acuity testing, is required to obtain motor vehicle license to drive taxies and trucks, according to the Road Traffic Act in Japan. The aim of this study was to examine whether the results of the three-rods test would correlate with the results of static stereopsis tests, used in ophthalmic practice.Methods: This study involved 54 normal subjects, 9 women and 45 men, with ages ranging from 18 to 25 (mean, 20.8) years. All had visual acuity of 0.8 or better with or without glasses or contact lenses correction and had no strabismus at the distant (5 m) or near (0.3 m) fixation. TNO Stereotest and Titmus Stereotest were examined at 40 cm while Distance Randot Stereotest was at 3 m. At three-rods test, a central rod was moved at the speed of 50 mm/sec forward and backward automatically against two laterally located fixed rods, placed inside the illuminated box. An examinee at the distance of 2.5 m observed the rods inside the box from a small viewing window and pushed a button to stop the central rod in alignment with the fixed rods. Erred distance (mm) of the central rod from the fixed rods as a mean of 4 measurements was correlated with stereoacuity in second of arc, measured by three kinds of the stereopsis tests.Results: The erred distance of three-rods test was positively correlated with static stereoacuity at distance measured with Distance Randot Stereotest (ρ = 0.418, p = 0.0023, Spearman rank correlation test) and also with the other stereopsis tests at near fixation. The stereoacuity at near fixation, measured by TNO Stereotest and Titmus Stereotest, was positively correlated with each other (ρ = 0.431, p = 0.0017).Conclusion: Three-rods test, examining depth perception, together with the response by eye-hand coordination, gave consistent results with distant static stereoacuity when measured with Distance Randot Stereotest.

Stereoacuity as an Indicator of Prism Adaptation

Purpose: The purpose of this study was to determine whether stereoacuity can be used as an indicator of prism adaptation. In particular, we wanted to know whether the time required for stereoacuity to return to the initial level after viewing through a prism can be used to determine the degree of adaptation.Materials and Methods: Eighteen subjects participated in this study. Stereoacuity and dissociated phoria were determined using the TNO stereotest and the Maddox rod, respectively. Prism vergences were measured using a prism bar. For each participant, prism power equivalent to the blur point of base-in (BI) and base-out (BO) fusional vergence at 40 cm was divided and placed in front of both eyes. At 0, 3, 6, 9 and 12 min after prism introduction, the stereoacuity was measured, and at 0 and 12 min, the heterophoria was measured.Results: The repeated measures ANOVA showed a significant difference between the mean stereoacuity for BI and BO prisms at the different measurement times (p < 0.05). For BO prism, the initial value was different between 0 and 3 min after the prism introduction, whereas for BI prism, a difference in stereoacuity was found between the pre-prism value and the value at 0, 3 and 6 min. The size of the heterophoria with BO and BI prisms was different from 0 to 12 min (p < 0.05).Conclusion: The time required for stereoacuity to return to baseline level was more than 3 min for BO, and more than 6 min for BI prism. In addition, the time required to return to baseline values was not similar for the stereoacuity and heterophoria. The recovery of stereoacuity is slower when adapting to divergence, as when looking from near to far. This implies that stereopsis responds faster to near targets than to distant one, and may precede complete phoria adaptation.

Stereopsis after successful surgery for rhegmatogenous retinal detachment

To evaluate stereopsis after successful surgery for unilateral rhegmatogenous retinal detachment (RD), and to investigate the relationship between stereopsis and clinical factors. In 75 patients after RD surgery and 28 age-matched normal subjects, stereopsis was measured using the Titmus Stereo Test (TST) and TNO stereotest. Clinical data were collected, including age, gender, circumferential dimension of retinal tears, area and duration of RD, macular status, surgical procedures, postoperative spherical equivalent, and logarithm of the minimum angle of resolution best-corrected visual acuity (logMAR BCVA), low-contrast visual acuity, postoperative lens status (phakia/pseudophakia), and presence of postoperative epiretinal membrane (ERM), to determine the factors related to stereopsis. Stereopsis in patients after surgery was significantly worse than normal subjects (p < 0.0001). Stereopsis in TST was significantly correlated with the area of RD (p < 0.005), difference of postoperative spherical equivalent between two eyes (p < 0.05), postoperative logMAR BCVA (p < 0.005), difference of postoperative logMAR BCVA between two eyes (p < 0.01), and low-contrast visual acuity (p < 0.05). Stereopsis in TNO stereotest showed significant association with postoperative logMAR BCVA (p < 0.05). Stereopsis in both stereotests were significantly worse in patients with macula-off RD than macula-on RD (p < 0.005, p < 0.01 respectively). No significant relationship was found between stereopsis and other factors. Multiple regression analysis revealed that macular status (on/off) had a significant correlation with both stereopsis in TST and TNO stereotest (p = 0.028, p = 0.019 respectively), whereas other clinical parameters were not relevant. Stereopsis is significantly deteriorated in patients after RD surgery than in normal subjects. Stereopsis was associated with the difference in refraction between two eyes, postoperative visual acuity and contrast sensitivity, and preoperative macular status.