Stereoacuity Research Articles

Apparent motion processing in strabismic observers with varying levels of stereo vision

Deficits of motion processing have been reported in individuals with infantile strabismus. Here we examined motion perception in early and late onset strabismic individuals with varying levels of stereo acuity using the Fine Grain Motion Illusion (FGMI). The FGMI is an illusion of motion, where under some conditions, observers report exaggerated motion. It has been speculated that this illusion is due to the spatial range of cortical cells stimulated. We used this illusion to compare this motion exaggeration in the central vision of both the deviating and non-deviating eye of strabismic observers with control eyes. While individuals with early onset strabismus showed some mild exaggeration of motion, those with low stereo acuity, regardless of age at onset, showed significantly larger exaggeration of this motion illusion in both the deviating and non-deviating eyes as compared with control observers. These results might indicate that this illusion and stereopsis involve common mechanisms.

Binocular Function of Intermittent Exotropia Before and After Surgery

Purpose: We examined the binocular function of intermittent exotropia before and after surgery, and studied the effect of the surgery and the factor that might be involved in its result. Materials and Methods: 402 intermittent exotropic patients, who underwent their first surgical correction for the strabismus at Teikyo University Hospital, were examined for retinal correspondence and stereo acuity before and after surgery. Results: 367 patients (91.3%) had already had good stereo acuity before surgery when their eyes were straight. Regarding retinal correspondence, though 192 patients (47.8%) were abnormal (dual) before surgery, 301 patients (74.9%) were normal after surgery. The eye deviation of 101 patients who could not get normal retinal correspondence after surgery was significantly larger than normal ( P < .001), and 77.2% of them had also vertical strabismus which was mainly composed of dissociated vertical deviation. Conclusion: Normal binocular function could be recovered by surgical treatment in most intermittent exotropic patients. When patients could not get normal retinal correspondence after surgery, we supposed that dissociated vertical deviation might exert an important effect upon their binocular function.

The Titmus Fly Test--evaluation of subjective depth perception with a simple finger pointing trial. Clinical study of 73 patients and probands

Subjects with different binocular defects were tested for their stereoscopic achievement. The determination of the subjects limiting disparity (in seconds of arc) was not used to characterize their stereoscopic acuity, but the subjective depth perception as a simple clinical method. 52 subjects with different binocular defects and 21 normosensoric volunteers were examined for their stereoscopic achievement. In our stereoscopic measurement we ask the subjects to indicate the subjective plane of the fly's wings manually by their own finger, or by a hand-held plastic card, or with the aid of a mechanic instrument. The results of the different methods were compared with each other. There were no differences between the results within the group of normosensoric subjects. The patients with reduced abilities exhibit significantly different results in depth perception when measured manually or by machinery. The subjective depth localization correlates well with the binocular defect and is independent of the used stereoscopic method. The basic finger test of the subjective level of the Fly's wings gives a quite reasonable approximation of local stereoscopic depth perception. In terms of practical investigation the finger test shows in convincing manner whether the individual stereoscopic ability is based on normal, subnormal or anomalous binocular interaction.

コントラスト感度の立体視検査法への影響

コントラスト感度の立体視検査法への影響

Visual Impairments in Elderly People under Everyday Viewing Conditions

This study measured the conventional high-contrast visual acuity, low-contrast visual acuity, low-contrast, low-luminance (SKILL) acuity, contrast sensitivity, disability glare sensitivity, glare recovery, stereo acuity, and visual fields of 900 elderly persons, including 450 aged 75–100. Although the prevalence of legal blindness and low vision were relatively low under conventional conditions, there were dramatic increases in these two conditions under low luminance or glare conditions. The practical implications of these findings are discussed.

High levels of binocular function are achievable after removal of monocular cataracts in children before 8 years of age

Objective To investigate the visual acuity and binocular function results achieved in children who had monocular cataracts removed before 8 years of age. Design Retrospective, noncomparative case series. Participants Clinical records of 171 patients who underwent a unilateral cataract removal between January 1986 and 1996 were reviewed retrospectively. Seventy-four eyes were included in the study: 19 congenital, 11 developmental, 19 posterior lenticonus, 19 traumatic, and 6 complicated cataracts. Patients with less than 2 years of follow-up; eyes with cataracts resulting from retinoblastoma; prematurity; and those associated with dense corneal scars, lens dislocation, and persistent hyperplastic primary vitreous were excluded. Intervention Visual acuity was measured by means of age-appropriate tests such as the fixation pattern, Allen object recognition cards, isolated optotypes with the Sheridan Gardiner test, and Snellen letters. Sensory fusion was assessed with the Worth 4-dot test, and stereo acuity was assessed with the Titmus stereo test. Main outcome measures Cataracts were classified regarding type, extent, age at onset, duration of the opacity, age at surgery, method of removal, development of secondary membrane , form of optical rehabilitation, and presence of strabismus. Visual acuity levels between 6/6 and 6/12 were considered “good.” Fusion of the Worth 4-dot test at distance and near, and presence of stereo acuity of 100 seconds of arc or better were considered “good” binocular function. Multiple logistic regression analysis was used to define factors that correlated with achieving good visual outcome. Results Visual acuity was 6/12 or better in 27 (36.5%) eyes. However, good binocular function was achieved in only 11 of these 27 patients. Results of univariate analysis showed that later age at onset of cataract and absence of strabismus were significant for good visual acuity and binocular function. The presence of strabismus increases the risk of not achieving good visual acuity by 5.45-fold. Conclusions Good visual acuity and binocular function can be achieved after removal of monocular cataracts in visually immature children. Patients with strabismus at presentation or during the follow-up period have the least chance of achieving a good sensory result.

Orbit orientation and the function of the mammalian postorbital bar

AbstractThe visual predation hypothesis of primate origins was introduced by M. Cartmill in the 1970s. In outlining a series of predictions regarding changes in orbital orientation, he further posits that the formation of a bony postorbital bar is correlated with greater orbital convergence, which in turn appears to be linked to selection for increased stereoscopic visual acuity in a nocturnal milieu. A series of predictions related to this model is tested in living analogues that vary in postorbital bar formation: felid and herpestid carnivorans and the pteropodid megabats. Bivariate correlations and regressions, ANOVA and ANCOVA are used to assess the intrinsic allometric and non‐allometric factors thought to affect two aspects of orbital orientation, convergence and frontation. These angles of orbital orientation are then examined in an effort to determine how they are associated with the development of a postorbital bar. Cartmill suggested that convergent orbits develop from changes in relative orbit diameter and relative interorbital breadth. This study indicates that felids show only weak support for these predictions, while herpestids do not provide support and pteropodids show some support. Instead, in response to natural selection, convergence seems to develop to improve stereoscopic vision and depth perception in nocturnal predators. As predicted, felids show a significant positive relationship between orbital frontation and relative brain size. Analyses in herpestids, however, do not show significant relationships between frontation and relative palate length or relative brain mass. Pteropodids also do not support the model regarding intrinsic frontation factors. In both carnivoran groups, convergence and frontation are positively correlated, whereas they are not correlated in Pteropodidae. In partial contrast to Cartmill's predictions, we found that orbital convergence and/or orbital frontation are generally higher in carnivorans and bats with postorbital bars. Therefore, a greater emphasis on nocturnal stereoscopic visual predation and increased relative brain size both move the orbital aperture out of the plane of the temporal fossa and a postorbital bar thus provides adequate rigidity to the lateral orbital margin. In the more encephalized Felidae, orbital frontation is positively correlated with relative brain size; as smaller mammals have relatively larger brains, this explains why postorbital bars tend to be found in smaller felids. In herpestids and pteropodids, postorbital bars tend to occur in larger taxa which are more convergent than smaller forms.

Distance alternate-letter suppression test for objective assessment of sensorial status in intermittent exotropia.

To investigate the value of distance alternate-letter suppression testing in the objective assessment of fusional control of intermittent exotropia. A total of 71 consecutive patients with intermittent exotropia (study group) and 112 normal subjects (control group) underwent a series of measurements including distance alternate-letter suppression testing, Worth 4 Dot test at distance and near, and distance and near stereo acuity tests to see whether sensorial behavior differed in the study and control groups. The distance alternate-letter suppression test and distance stereo acuity tests were performed using the Mentor B-VAT II-SG Video Acuity Tester and Binocular Vision Testing System. The TNO test was used to measure near stereo acuity. Seventeen patients with intermittent exotropia (24%) presented suppression with the distance alternate-letter suppression test, but none of the normal subjects (p<0.001, chi2 test). Only, three patients (4%) showed suppression on the Worth 4 Dot test at distance, and all had fusion on the Worth 4 Dot test near. Patients with intermittent exotropia had significantly diminished distance stereo acuity compared to normal subjects (p<0.001). Normal subjects and patients had good near stereo acuity (p>0.05). Patients with intermittent exotropia who had fusion with the distance alternate-letter suppression test had significantly better distance stereo acuity than patients who had suppression (p<0.001). Distance alternate-letter suppression testing and distance stereo acuity tests may be useful as objective measures for assessing sensory loss in patients with intermittent exotropia.

Results of early alignment of congenital esotropia

Objective To determine the long-term motor and sensory results after early surgical correction of patients with congenital esotropia. Design Noncomparative interventional case series. Participants Ten infants with congenital esotropia. Intervention Patients had bimedial rectus recession between 83 and 159 days of age; were re-examined in a regular follow-up program; and were retreated when required for strabismus, amblyopia, and refractive errors. Main outcome measures Final alignment, stereo acuity, variations in vision, alignment, refraction, and number and types of retreatments required during the period of observation. Results All patients were aligned initially with bimedial rectus recession of 8.0 to 10.0 mm measured from the limbus. A total of 11 additional surgical procedures were performed on 7 patients to maintain alignment. Four patients required hyperopic spectacle correction to maintain alignment, and two patients required short periods of patching. Visual acuity was 20/40 or better in 19 eyes at the most recent examination, which was between 8.3 and 11.8 years after initial surgery. All patients had final alignment to within 10 prism diopters (PD) of orthotropia at either distance or near. Nine of ten patients had dissociated vertical deviation (DVD), and four of ten patients had latent nystagmus. Four patients had measurable stereo acuity at their last visit, with two achieving a stereo acuity of 3000 seconds (the Titmus fly), one 400 seconds, and one 140 seconds. Conclusion Surgical alignment of congenital esotropia can be achieved in the 4-month-old with bimedial rectus recession, but this does not ensure continued alignment. At least one additional surgical procedure is required on average to maintain alignment in the first 10 years after initial successful surgery. These patients can also be expected to have one or more of the following: DVD, latent nystagmus, refractive component, or latent strabismus. Regardless of outcome, patients with congenital esotropia have optokinetic asymmetry. Attainment of stereo acuity, including high-grade stereo acuity, may be enhanced by attainment of orthotropia or small-angle esotropia but is likely to be ultimately dependent on constitutional factors rather than age of alignment.

Binocular function and patient satisfactionafter monovision induced by myopic photorefractive keratectomy

Purpose: To measure binocular function and patient satisfaction with monovisioninduced by photorefract ve keratectomy (PRK) in myopic presbyopic patients. Setting: Refractive Department; Cleveland Clinic; Cleveland, Ohio, USA. Methods: This study comprised 21 myopic presbyopic patients with monovisioninduced by PRK. Sixteen emmetropic patients who had PRK served as a control group. Monovision was induced by undercorrecting the nondominant eye by 1.25 diopters for near vision and correcting, the dominant eye with emmetropia for distance vision. Monocular and binocular uncorrected Snellen visual acuities at 20 feet and 13 inches, manifest refraction, ocular dominance, stereopsis at 20 feet and 13 inches, Monocular and binocular contrast sensitivities, Worth-4-Dot test at 20 feet and ⅓ of a meter, and fusional convergence amplitudes were examined in each patient. Results: In the monovision group at near and distance, 20 patients (95.3%) had binocular visual acuity of 20/25 or better. No patient in the monovision group used reading glasses postoperatively; 4 of 16 patients (25.0%) in the control group used such glasses. All patients maintained binocular fusion and stereo acuity ranging from 40 to 800 seconds of arc. Mean patient satisfaction was 86% (range 40% to 100%). In the control group, 12 patients (75.0%) had binocular distance visual acuity of 20/25 or better and 11 (68.8%) had binocular near visual, acuity of 20/25 or better. Conclusion: Monovision PRK patients had better near vision than control PRKpatients, with minimal compromise in stereo acuity and overall high patient satisfaction.

Lens induced aniso-accommodation.

Despite the evidence for consensual accommodation in response to consensual accommodative stimuli, only a few studies have investigated the binocular accommodative response to unequal (aniso) accommodative stimuli. Past studies investigating an unequal binocular accommodative response (aniso-accommodation) to aniso-accommodative stimuli have been limited by viewing conditions and measurement technique making the results, which were equivocal, difficult to interpret. This investigation addressed these limitations by the following design parameters: (1) monocular dichoptic blur cuese were provided in the binocular stimulus target to provide subjects feedback on their aniso-accommodative response and to alert the investigator of a monocular blur suppression response; (2) a training period was provided; (3) in the subjective method, each eye's stigma was positioned near the dichoptic letter viewed by the other eye. By this method, a true aniso-accommodative response could be differentiated from successive consensual responses; (4) a large range of aniso-accommodative stimuli was used, 0.50-3.0 D, presented in incremental steps of 0.5 D, allowing measurement of an average 0.75 D aniso-accommodative response for the highest (3.0 D) aniso-accommodative stimulus; (5) aniso-accommodation was measured as a function of viewing distance. For four of seven subjects, the gain of the aniso-accommodative response was significantly greater at near than at far viewing distances; (6) aniso-accommodation was confirmed objectively with measures of the response to steady state and step aniso-accommodative stimuli, using a binocular SRI Dual Purkinje Eye Tracker Optometer System. The aniso-accommodative response to step stimuli showed a very long latency period (about 11 s) and a response time of 4.5 s. A potential benefit of aniso-accommodation would be to overcome small amounts of uncorrected anisometropic refractive error. This would preserve fine stereo acuity which is impaired by unequal intraocular image contrast. Aniso-accommodation also may provide an appropriate efferent feedback signal for each eye's unique refractive error which could be used to guide developmental isometropization (attainment of equal refractive error in the two eyes.).

Recovery in microtropia: implications for aetiology and neurophysiology

AIMS/BACKGROUNDThe basis of binocular single vision in microtropia remains a matter of contention. This paper discusses the implications of recovery, in a group of primary microtropes following treatment, in relation...

Lines and gabor functions compared as spatial visual stimuli

Foveal discrimation tresholds were measured for orientation, vernier alignment, bisection, displacement detection and stereoscopic acuity using simple line stimuli and also sinusoidal grating patches with gausslan intensity modulation (Gabor stimuli). Stimulus parameters such as luminance, exposure duration, component separation and, as far as possible, length were identical for both. Orientation discrimination as a function of length is almost identical for the two classes of stimuli, some observerse performing slightly better with Gabor patches. Thresholds for displacement detection are also the same. Vernier, stereo and bisection acuities, however, are considerable better with line than with Gabor stimuli.

Temporal Integration of Alternately Exposed Monocular Images of a Random-Dot Stereogram

J R Ewald and O Gross (1906 Pflügers ArchivCXV 514 – 521) reported that monocular half-images presented alternately can be fused to a stereoscopic percept. The situation is like looking through a fence close to the eyes, with picket and gap widths being identical to the interpupillary distance. Though vision is monocular, an observer moving fast enough parallel to the fence will have stereoscopic vision of the scenery behind it. Little is known about the limits of this integrating mechanism. In two experiments, LCD shutter glasses were used to control the viewing conditions of the anaglyphs of a random-dot stereogram. Binocular fusion was supported by a visible binocular fixation mark and a frame around the display. Subjects were eight male and three female students with normal stereoscopic acuity. They were instructed to press a key as long as they could perceive a global figure portrayed in the stereogram (25 min arc disparity). In experiment 1, monocular exposures to the right and the left eye followed each other without pauses. Psychophysical procedures were used to determine the frequency threshold for stereopsis. A breakdown frequency of 2.5 Hz was found, for descending as well as ascending series. Transferred to the concrete example of a fence, the result corresponds to a pace of 0.32 m s−1, with an interocular distance and a fence measure of 63 mm. In experiment 2, alternating monocular exposures of 100 ms duration were separated by variable pauses. Stereopsis disappeared with 8 ms pauses (ascending), and 17 ms pauses (descending). Results may be attributed to integrating mechanisms of binocular cortical cells, rather than to retinal processes (afterimages).

Surgical treatment of superior oblique palsy

Reports of several large series of patients with superior oblique palsy (SOP) published in 1986 or before set forth important guidelines for both diagnosis and treatment of this condition. Newer information about the anatomy, physiology, and pathophysiology of the superior oblique has accrued over the past decade. This paper reviews our experience with diagnosis and treatment of SOP over the past 5 years in light of this new information. Charts of patients treated for SOP over 5 year (1990 to 1995) were reviewed for male or female sex, age, symptoms, refraction, vision, stereo acuity, head posture, facial asymmetry, intraoperative superior oblique traction test, diagnostic position prism and cover test, torsion, surgery performed, and results of treatment. The charts of 190 patients were reviewed. In 181, postoperative examinations were performed by us. The etiology of the SOP was congenital in 137 and acquired in 53. Twenty-nine acquired cases were due to trauma and 24 arose from other causes. Fifty-six patients had facial asymmetry, 51 of whom had congenital SOP. Ninety-five had a lax tendon, 83 (87%) of whom had congenital SOP. Sixty-six had a normal tendon, 29 (44%) of whom had acquired SOP. Seventy-seven percent of patients had Knapp class I, III, or IV palsy. An average of 1.26 surgeries was performed per patient. Inferior oblique weakening was performed in 177 (93%), while 68 vertical rectus recessions were done. Thirty-five patients had superior oblique tuck or resection, all on lax tendons, and 15 had Harada Ito procedures for torsion. Six patients had mild Brown syndrome postoperatively, none of which required a takedown. A cure, defined as relief of symptoms or elimination of strabismus and head tilt, was achieved in 166 of 181 (92%) of patients. Successful treatment of SOP can be accomplished in the majority of cases by selective surgery usually beginning with inferior oblique weakening plus additional vertical rectus and horizontal surgery as needed, with superior oblique strengthening used only for lax tendons or when torsion is the main problem.

Results following secondary intraocular lens implantation in children

Placement of a secondary intraocular lens (IOL) in a child may be considered in children with congenital monocular cataracts who have had complete opacities removed early in life and who later become contact lens intolerant, in eyes that have received trauma which precluded placement of a primary IOL, and in young adults who have bilateral aphakia who become resistant to use of contact lenses or spectacles. Clinical records of all children in our practice who received a secondary IOL between January 1988 and December 1994 were reviewed. Indications, biometry, type of procedures, preoperative and postoperative acuity, refractive error, binocular status, and complications were studied. During the 7-year period, 242 cataract operations were performed. Fifty-nine eyes received a lens implant, and 28 of these were secondary implants. There was a mean interval between the initial cataract operation and the procedure for the secondary implant of 77 months. The mean follow-up was 35 months (range, 3 to 71) for the 28 eyes that received a secondary implant. Two received anterior chamber implants. Eight eyes had insufficient capsular support for an IOL. Six implants were placed in the posterior chamber and required suture fixation to the sclera. Twenty of 28 eyes had a measurable improvement in visual acuity. Only 1 eye had a decrease in visual acuity of 2 lines. Fifteen patients (54%) had a final refraction within 1.50 diopters of the fellow eye, and 75% were within 3.00 diopters. During the follow-up period, 2 eyes developed glaucoma. One had a transient pressure elevation, and the second has required 2 filtration procedures. Three patients required a Nd: YAG capsulotomy. Six patients demonstrated Worth fusion at distance and near, but only 3 patients demonstrated 200 seconds of arc or better stereo acuity. Placement of contemporary-style, secondary intraocular lenses in children and young adults appears to provide a safe and effective alternative for correction of aphakia in children who become contact lens or spectacle-intolerant.

Changes in oculomotor functions before and after loading of a 3-D visually-guided task by using a head-mounted display.

Changes in visual and oculomotor functions were tested in eight young volunteer subjects after performing a 3-D visually-guided task for 25 min. The visual stimuli were given by using a head-mounted display. No significant change was detected in the AC/A ratio and the stereo acuity. Changes were found in refraction and ocular convergence. Slight but significant hyperopic changes were detected in refraction after the task. The mean amplitude of convergence eye movement elicited by test stimuli after the task was significantly changed in the pooled data. They were significantly reduced when the subjects were tested by the disparity step of 0.7 degrees, but significantly increased when tested by the step of 6 degrees. The mean amplitudes were not significantly changed after the task when the subjects were tested by the intermediate disparity steps of 1.5 and 3 degrees. In data obtained for each subject, the amplitude of ocular convergence evoked by test stimuli after the task was reduced significantly in most subjects. In the majority of subjects, however, the results were not consistently significant when they were tested by step stimuli with different disparities. In only a few subjects, the changes were consistently significant except when the largest disparity was tested. On the other hand, the mean peak velocities of ocular convergence after the task were not significantly changed in the pooled data. In individual subjects, the changes of velocities of ocular convergence evoked by test stimuli after the task were more variable: they increased in some subjects but decreased in other subjects. Consequently, in only one subject, both amplitudes and peak velocities of ocular convergence tested by the disparity steps of 0.7, 1.5 and 3 degrees were consistently reduced after the task. The changes in refraction or ocular convergence found in this study were relatively small, and were not in the pathological range. The significance of these data are discussed. The results of the present study provide the basis for the more detailed analyses of the human factor in the head-mounted display.

Clinical optokinetic nystagmus asymmetry in treated esotropes.

Monocular optokinetic nystagmus (OKN) asymmetry is associated with disruption of early binocular visual development. Three groups of treated esotropic patients and a group of normal controls were evaluated for the presence of clinically detectable monocular OKN asymmetry. Clinical assessment of monocular OKN asymmetry was performed by observing eye movements in response to a hand-held rotating drum. Asymmetry was quantitated on a scale of 0 to +3 OKN asymmetry. Clinical OKN asymmetry was evaluated in the following groups of patients: those with congenital esotropia treated with very early surgery achieving high-grade stereo acuity (group 1); those with congenital esotropia treated with late surgery achieving no stereopsis (group 2); those with acquired esotropia achieving high-grade stereo acuity after treatment with spectacle correction (group 3); and normal controls (group 4). Two of the three patients in group 1 showed +3 OKN asymmetry despite having high-grade stereo acuity; the third one, who was surgically aligned earliest (13 weeks), demonstrated +1 OKN asymmetry. This patient achieved orthotropia, 40 seconds stereo acuity, perfect Randot stereo acuity, and had no dissociated vertical deviation or latent nystagmus. All 10 patients in group 2 (those with late alignment-after 1 year-and no stereo acuity) showed +3 OKN asymmetry. All four patients in group 3 (those with acquired hypermetropic esotropia and high-grade stereo acuity after treatment) and all 10 patients in the normal control group showed no OKN asymmetry. Clinically obvious monocular OKN asymmetry can occur in patients with congenital esotropia who are aligned early and develop high-grade stereo acuity. Even brief periods of strabismus during the early period of binocular motor development can result in persistent OKN asymmetry. This suggests that binocular motor processing may develop distinct from, and prior to, the development of high-grade stereo acuity. OKN asymmetry appears to be a clinical sign of an insult to early binocular motor development.

Infantile exotropia.

Exotropia is uncommon in healthy children between 6 months and 1 year old. The charts of patients treated in our practice between January 1980 and August 1994 were reviewed for a diagnosis of infantile exotropia. All of them had an exodeviation during the first year of life. Children with neurologic defects, prematurity, trauma, craniofacial syndromes, or orbital abnormalities or ocular defects that would reduce vision were eliminated. Sixty-six healthy patients with normal eyes had an exodeviation of 15 prism diopters (delta) or more that persisted through the first year of life. Fifty-four were eliminated because the diagnosis had not been confirmed by a pediatric ophthalmologist before they were 1 year old or they had not been followed for more than 4 years. The 12 remaining patients were followed for at least 4 years (mean, 7.9 years). The mean age at the first examination was 7.8 months (range, 4 to 12 months). On early evaluation, exotropia was intermittent in four and constant in eight. Three had amblyopia. Ten required surgical correction. Exotropia was corrected with one operation in six patients; four required additional procedures, mostly to correct oblique muscle overaction and dissociated vertical deviation (DVD). At the most recent visit, all 12 patients had equal visual acuity in both eyes and satisfactory ocular alignment. Five had fusion at distance and near, but only two had stereo acuity of 100 seconds of arc or better. Infantile exotropia is rare. But, like patients with infantile esotropia, those with exotropia can be expected to have good visual acuity but unstable ocular alignment. Also, as with early-onset esotropia, although surgical intervention is usually required, high levels of binocular function develop in some patients with exotropia. Oblique muscle overaction and DVD are common, often becoming manifest by the first year of age. Unlike infantile esotropia, nystagmus is rare.

The visual status of the nursing home resident

Abstract Objective: To determine the visual status and eye care needs of long-term care nursing home residents. Study design: Eye examinations were performed on 39 nursing home residents (mean = 72.1 years, range 39–94, 36 males and three females) in the Department of Veterans Affair long-term care facility. The prevalence of low vision and legal blindness as well as ocular conditions in this population was recorded. Results: The results of 39 eye examinations indicate that a high prevalence of low vision and legal blindness as well as ocular conditions such as cataracts, macular degeneration, and glaucoma exist in these nursing home residents. There were also large percentages of people with reduced contrast sensitivity, reduced stereo acuities, and visual field defects. Conclusion: The findings indicate a large need for routine eye care in this population