Stereoacuity and Multifocal Intraocular Lenses - a Systematic Review.

Background: Among various visual functions, stereoacuity, or the ability to perceive depth, is the most sophisticated binocular function. Many publications discuss the influence of retinal image formation by multifocal intraocular lenses on glare and contrast sensitivity, but only a few present results of testing binocular vision in patients with multifocal intraocular lenses. Objective: This article is designed to review the results of testing binocular vision in patients with multifocal intraocular lenses implanted in cataract surgery. Methods: This article was performed based on a literature review and Internet search through scientific databases such as PubMed, Scopus, Web of Science, and Google Scholar. Results: Some reports found that patients implanted with the monofocal lens, when measured with a near addition, presented statistically significant better stereoacuity scores than those implanted with any of the multifocal intraocular lens types. When the TNO test was used for measurement, statistically significant better stereoacuity was disclosed with the refractive multifocal intraocular lens than with the diffractive-based multifocal intraocular lens design. Stereoacuity scores, even within the same types of lenses, were significantly better with the Titmus test than with the TNO test. Conclusion: Stereoacuity is not affected by multifocality-induced retinal blur as it is by other causes of image degradation such as small residual refractive error very early opacification of ocular media or dry eye. Multifocal intraocular lenses do not cause more functional aniseikonia than would be expected with a monofocal intraocular lens. Since stereoacuity is compromised with unilateral multifocal intraocular lens implantation bilateral implantation should be attempted.

Modification of the titmus fly test to improve accuracy.

INTRODUCTION: In spite of its well-known flaws, the Titmus test is still the most commonly available and frequently utilized stereotest worldwide. Detecting stereopsis in the patient with small-angle strabismus is an important part of the sensorimotor exam. Because these patients often have only gross stereopsis, stereoacuity may have to be evaluated with the House Fly plate alone. This study evaluates an alternative method of presentation designed to decrease the false positive rate of the Titmus Fly test. METHODS: A group of orthotropic volunteers with normal binocular vision, a group of patients with small angle strabismus, and a group of patients whose angle of strabismus was large enough to preclude stereopsis were tested with the Titmus Fly using two different presentations and compared. RESULTS: The sensitivity of the Titmus Fly test was 79%, but specificity was only 26% due to the large number of false positive responses detected with the modified presentation. Patients with childhood-onset strabismus who have been repeatedly exposed to this test over many visits were particularly vulnerable to overestimation of stereoacuity. CONCLUSION: If the Titmus fly test is the only stereoacuity measure that can be used due to the presence of manifest strabismus, modifying the presentation of the test plate with this method will improve accuracy and precision of results.

The Change of Sensory Binocularity according to the Surgical Results in Intermittent Exotropia

PURPOSE: This study was designed to determine which sensory test best reflects the improvement of binocular function according to the surgical outcome of intermittent exotropia METHODS: We examined the visual acuity, refractive error, angle of exodeviation, fusional status with the Worth-4-dot, Bagolini tests and stereoacuity with the Titmus test preoperatively in 61 intermittent exodeviation patients who had undergone the bilateral lateral rectus recession operation from February 2002 to 2003 July. We compared the binocularity tests between the two groups: esodeviated and orthotropic or exodeviated. RESULTS: The average improvement time of the Bagolini, Worth 4 dot and Titmus tests was 0.54 +/- 1.2, 2.03 +/- 2.90, 1.12 +/- 2.1 weeks, respectively. Although the shortest time was for the Bagolini test (p=0.001), the Titmus test was more sensitive. CONCLUSIONS: The high variability of the binocularity tests should be remembered and take into account when we interpret the test results.

Change of Stereoacuity with Aging in Normal Eyes

PURPOSE: Stereopsis in normal subjects aged between 7 and 76 years was compared to examine changes in stereopsis with age. METHODS: Eighty subjects with no ocular disease were divided into 8 groups by age. Near stereopsis was evaluated with the TNO, Titmus, and Randot tests; distance stereopsis with the Mentor B-VAT II video acuity tester. RESULTS: The results of all 4 tests showed decreased stereopsis with increasing age (p< 0.05). Compared to the stereoacuity of 7 to 10-year-old group, both the TNO and distance stereopsis test results were significantly decreased for the 6th, 7th, and 8th decade groups, while both the Titmus and Randot test results were significantly decreased for the 8th decade group (p< 0.05). CONCLUSIONS: Overall, both near and distance stereopsis decreased with increasing age. Thus, decreased stereopsis should be taken into account when performing the stereopsis test.

The Usefulness of Titmus Test and Distance Stereoacuity Using B-VAT(R) in Intemittent Exotropes

PURPOSE: Stereoacuity test is commonly used to determine the status of sensory function in patients with strabismus. We performed Titmus test and Mentor B-VAT II videoacuity tester in patients with basic or simulated divergence excess type intermittent exotropia {X(T)}, before and after surgery, to determine the effectiveness of near stereoacuity and the correlation between near stereoacuity and distance stereoacuity. METHODS: Near stereoacuity was measured using Titmus test and distance stereoacuity was measured using a Mentor B-VAT II videoacuity tester, before and after surgery, in 41 patients with X(T). RESULTS: The stereoacuity according to Titmus test was improved from a preoperative average of 70 seconds of arc to postoperative average of 60 seconds; however, this improvement was not statistically significant (P=0.38). Distance stereoacuity was significantly improved from a preoperative average of 221 seconds to a postoperative average of 60 seconds (P=0.001). No significant correlation was present between preoperative near stereoacuity and distance stereoacuity (P=0.99). CONCLUSIONS: Titmus test was not effective in determining the status of sensory function before and after surgery in patients with basic or simulated divergence excess type X(T). We believe that distance stereoacuity is effective in determining the status of sensory function.

Sensory Status in Patients Showing Orthophoria After Strabismus Surgery in Exotropes

PURPOSE: The purpose of this study is to evaluate sensory function and stereoacuity in patients showing orthophoria after surgery in exotropes, and to elucidate factors influencing postoperative improved sensory status METHODS: We prospectively studied 45 patients showing orthophoria or exophoria within 4 prism diopters after strabismic surgery in exotropes. Three tests (Worth-4-dot test, Bagolini striated lens test and Titmus test) were performed at pre and postoperative period. We studied the effect of different variables (age at surgery, visual acuity, angle of deviation, Bagolini striated lens test, Titmus test, anisometropia, and fusional status) with suspected clinical influence on the sensory and motor outcomes. RESULTS: In Worth-4-dot test, 34 patients (75.6%) showed improvement after surgery. Thirty-three patients (73.3%) and 35 patients (77.8%) showed improvement respectively in the Bagolini striated lens test and Titmus test. Thirty-eight patients showed improvement in 2 or more tests after surgery and 7 patients showed no change. Of patients showing preoperative abnormal response in each test, 21 patients (65.6%) in Worth-4-dot test, 14 patients (53.8%) in Bagolini striated lens test, and 22 patients (68.8%) in Titmus test showed normal response at postoperative 6 months. Of 3 tests and other factors, Bagolini striated lens test was the only factor predicting postoperative sensory recovery (x2=4.18, P<0.05). CONCLUSIONS: In patients showing orthophoria or exophoria within 4 prism diopters after strabismic surgery in exotropes, Bagolini striated lens test was the only meaningful factor predicting postoperative sensory recovery