Measuring colour rivalry suppression in amblyopia.

AIMS: To determine if the colour rivalry suppression is an index of the visual impairment in amblyopia and if the stereopsis and fusion evaluator (SAFE) instrument is a reliable indicator of the difference in visual input from the two eyes. METHODS: To test the accuracy of the SAFE instrument for measuring the visual input from the two eyes, colour rivalry suppression was measured in six normal subjects. A test neutral density filter (NDF) was placed before one eye to induce a temporary relative afferent defect and the subject selected the NDF before the fellow eye to neutralise the test NDF. In a non-paediatric private practice, 24 consecutive patients diagnosed with unilateral amblyopia were tested with the SAFE. Of the 24 amblyopes, 14 qualified for the study because they were able to fuse images and had no comorbid disease. The relation between depth of colour rivalry suppression, stereoacuity, and interocular difference in logMAR acuity was analysed. RESULTS: In normal subjects, the SAFE instrument reversed temporary defects of 0.3 to 1. 8 log units to within 0.6 log units. In amblyopes, the NDF to reverse colour rivalry suppression was positively related to interocular difference in logMAR acuity (beta=1.21, p<0.0001), and negatively related to stereoacuity (beta=-0.16, p=0.019). The interocular difference in logMAR acuity was negatively related to stereoacuity (beta=-0.13, p=0.009). CONCLUSIONS: Colour rivalry suppression as measured with the SAFE was found to agree closely with the degree of visual acuity impairment in non-paediatric patients with amblyopia.

Illuminated near card assessment of potential acuity in eyes with cataract.

OBJECTIVE: This study aimed to determine the accuracy and potential role of the illuminated near card (INC) for predicting visual outcome after cataract surgery in eyes with and without comorbid disease. STUDY DESIGN: A consecutive case series. PARTICIPANTS: A total of 101 preoperative patients with cataracts participated. MAIN OUTCOME MEASURES: Accuracy of predicted postoperative distance acuity was measured. METHOD: The preoperative acuity obtained with the INC was compared by linear regression to the postoperative INC acuity and the postoperative distance acuity for 100 consecutive eyes undergoing cataract surgery. Variables analyzed were preoperative distance acuity and the presence or absence of comorbid disease. RESULTS: The preoperative INC acuity was significantly predictive of postoperative INC (P = 0.0005) and postoperative distance (P = 0.0007) acuities for the 100 eyes studied. For the subgroup of 15 eyes with 20/200 or worse, the preoperative INC acuity was not predictive of postoperative INC acuity (P = 0.8673) or postoperative distance acuity (P = 0.8789). For the 21 eyes with comorbid disease, the predictions were more accurate for postoperative INC acuity (P < 0.0001) and postoperative distance acuities (P < 0.0001) than for 64 eyes without comorbid disease: postoperative INC acuity (P = 0.0051), and postoperative distance acuity (P = 0.0046). The INC predicted postoperative distance acuity to within two lines in 98% of eyes when preoperative distance acuity was 20/100 or better. When the preoperative distance acuity was 20/200 or worse, the postoperative distance vision was predicted to within two lines in only 53% of the eyes. CONCLUSION: The INC can be a useful adjunct for predicting postoperative distance acuity in eyes with cataract that have preoperative distance acuity of 20/100 or better, particularly in eyes with comorbid disease, in which the clinical judgment of vision potential may be difficult.

Ocular siderosis. Diagnosis and management.

PURPOSE: To assist clinicians in the diagnosis and management of ocular siderosis. METHODS: The diagnosis and management of three cases of ocular siderosis secondary to a retained iron-containing intraocular foreign body are described. RESULTS: Noteworthy features included: 1) the characteristic features of a tonic or Adies pupil (one case) and 2) the failure of high-resolution computed tomography scanning and plain film radiography to detect the intraocular foreign body (two of three cases). In contrast, ultrasonography demonstrated the intraocular foreign bodies in all cases and accurately localized them to the inferior retinal quadrants. A third noteworthy finding was that a preoperative electroretinogram reduction in amplitudes of as much as 40% compared with that of the uninvolved eye was compatible with excellent vision, and that the electroretinogram returned to normal after the intraocular foreign body was removed. CONCLUSIONS: Ocular siderosis should be considered in the differential diagnosis of a tonic or Adies pupil. To detect an occult intraocular foreign body, clinicians should not rely exclusively on computed tomography scanning or plain film radiography, but should also use B-mode echography with careful study of the inferior quadrants. In ocular siderosis a preoperative electroretinogram reduction in amplitudes of as much as 40% may be reversible after intraocular foreign body removal.

Baseball hitting, binocular vision, and the Pulfrich phenomenon.

OBJECTIVES: To determine if dimming the light to 1 eye affects baseball hitting (motion-in-depth) and if binocular interaction influences the ability to hit a baseball. METHODS: The ability to hit baseballs in a batting cage was measured under conditions of (1) no filter before either eye, (2) neutral density filters before both eyes, and (3) a neutral density filter before 1 eye, while viewing with both eyes. Batting scores were based on the number of hits, fouls, and misses. RESULTS: A neutral density filter of 0.6 optical density before both eyes had no significant effect on batting ability compared with no filter (87% vs 94%). While viewing binocularly, a filter before 1 eye caused a significantly greater reduction in hitting scores than when the filter was placed before the opposite eye (36% vs 80%). This greater effect of 1 eye on hitting scores denotes an ocular preference or dominance within the motion stereopsis system. The eye associated with the greater reduction in hitting ability when dimmed by a filter was termed the dominant eye for motion stereopsis. In comparison with placing 0.6-optical density filters before both eyes, the same filter before the dominant eye reduced hitting ability (36% vs 87%), but when the filter was placed before the nondominant eye, the hitting ability was not significantly reduced (80% vs 87%). The batting scores decreased as filter densities increased from 0.3- to 0.6-optical density, and the effect was significantly more for the dominant eye than for the nondominant eye. CONCLUSIONS: Binocular vision contributes to the precise localization of a pitched baseball, and one eye influences baseball hitting more than the other eye. The motion-in-depth channel (baseball hitting) shares a sensitivity to unequal binocular illumination with the sideways-motion channel (Pulfrich phenomenon). The timing of the impulses conducted from the eyes appears to be critical for the precise localization of objects processed by either the motion-in-depth (baseball hitting) or the sideways-motion (Pulfrich phenomenon) channels.

Illuminated near card assessment of potential visual acuity.

PURPOSE: To determine the accuracy of predicting potential visual acuity in patients having neodymium:YAG (Nd:YAG) laser capsulotomy using a new device, the illuminated near card (INC). SETTING: Private practice, New York, New York. METHODS: Thirty-eight consecutive patients having Nd:YAG laser capsulotomy were studied prospectively by comparing the postoperative distance Snellen acuity to the visual acuity obtained preoperatively using (1) a near reading card, (2) the INC, and (3) the INC viewed through a pinhole. RESULTS: Patients reported that the INC was easy to use; none with a visual acuity better than 20/200 had difficulty finding the illuminated letters through the pinhole. In eyes with a precapsulotomy distance acuity of better than 20/200, the correlation between precapsulotomy and postcapsulotomy acuities was statistically significant (P < .001) for the INC viewed through the pinhole. A significant correlation between precapsulotomy and postoperative acuities was not found for the INC viewed alone or for the near card (P > .05). In patients with a precapsulotomy distance acuity of 20/200 or worse, the INC with pinhole, the INC, or the near card did not predict postoperative acuity (P > .05). CONCLUSION: In eyes with a precapsulotomy distance acuity better than 20/200, the INC with pinhole predicted postoperative distance acuity within one Snellen line in 97% of eyes (29/30), which is comparable to reports using other potential acuity testers. The INC viewed through a pinhole improves image resolution by the stenopaic hole without the low light intensity of the reduced aperture.

Pulfrich psychophysical stereo-illusion and visual-evoked potentials in epiretinal membrane of the macula.

Six patients with unilateral epiretinal membrane of the macula perceived the spontaneous Pulfrich psychophysical stereo-illusion, suggesting a relative conduction delay on the side of the membrane. In three of these patients, visual-evoked potential studies were also obtained and confirmed an absolute conduction delay in the anterior pathway on the side of the epiretinal membrane in two patients and an absence of the P 100 wave on the side of the epiretinal membrane in the third patient. It is important to recognize that the Pulfrich psychophysical stereo-illusion can be spontaneously perceived in macula disease, and therefore, the test may not always distinguish optic nerve from macula disease.

Stereophotometric testing for Pulfrich's phenomenon in professional baseball players.

Major League players were significantly more accurate in performing stereophotometry than were Minor League players. The stereophotometric data based upon the induction and extinction thresholds of the Pulfrich phenomenon were significantly correlated with the batting averages of Major League baseball players. The coefficient of determination, r2, implies that visual ability as measured by stereophotometry accounts for 47% or more of the variation in batting averages of the Major League players. This test may be a useful index in predicting batting ability.

Serologic tests in the diagnosis of presumed toxoplasmic retinochoroiditis.

We treated three patients who had documented Toxoplasma retinochoroiditis and negative immunofluorescent antibody toxoplasmosis titers (titer less than 1:16), positive Sabin-Feldman dye titers of 1:64, 1:16, and 1:64 in the three patients, respectively, and a positive enzyme-linked immunoassay titer of 1:256 in the one patient tested. In patients with negative immunofluorescent antibody toxoplasmosis titers, we recommend obtaining Sabin-Feldman or enzyme-linked immunoassay titers, or both, before excluding the diagnosis of ocular toxoplasmosis.

Pulfrich stereo-illusion phenomenon in serous sensory retinal detachment of the macula.

Four patients (three men, 68, 35, and 33 years old, and one woman, 46 years old) had central serous elevation of the macula with abnormal latency of the visual-evoked potential and spontaneous Pulfrich phenomenon. In three instances both the electrophysiologic test and the clinical Pulfrich test reverted to normal on resolution of the retinopathy. This correlated with normalization of visual-evoked potential latency in the affected eye.

Presumed toxoplasmic retinochoroiditis in four siblings.

Four siblings in an East Indian family showed typical ophthalmoscopic findings of toxoplasmic retinochoroiditis. Serologic data confirmed exposure to Toxoplasma gondii and the results of other tests excluded other etiologic agents. Three siblings had documented episodes of ocular inflammation consistent with recurrent toxoplasmic retinochoroiditis. The fourth sibling developed a de novo lesion following an illness consistent with systemic toxoplasmosis.

Cytomegalovirus retinitis in a young homosexual male with acquired immunodeficiency.

A case is reported of histopathologically documented CMV retinitis. It is part of a recently appreciated syndrome in young homosexual men, in which cellular immune deficiency has been documented and in which CMV infection may play a role. This case demonstrates that CMV retinitis is not excluded by negative CMV serology or cultures.

Orbitofacial angiomatosis.

Two patients with orbital vascular malformation ipsilateral facial nevus flammeus were studied. The literature contains one similar case that interestingly shares with our cases the lack of leptomeningeal angiomatosis. Orbitofacial angiomatosis seems to be a distinct entity from meningofacial angiomatosis because of its true vascular malformation of the orbit.

Intralesional corticosteroid therapy of chalazia.

Twelve adult patients with 17 chalazia underwent trial intralesional injection of triamcinolone acetonide. Seven chalazia resolved within two weeks after only one injection, and another six after two injections. Two lesions failed to respond to two injections, and two lesions responded to one injection, but either recurred or another lesion developed. Patients were satisfied with the procedure, which appears to be a safe, convenient, and effective altefnative to chalazion surgery.