Vision information center: a user-oriented data base.

In response to the information needs of scientists and physicians who work in the field of vision, we have developed a direct-access, on-line specialized information retrieval system which combines computer-assisted instruction and bibliographic retrieval. An essential feature of the system is its accessibility via remote computer terminal. The key to the data base is a thesaurus which contains specific terminology arranged in a hierarchical structure. The thesaurus is used both for indexing the literature and for retrieving the information stored in the computer. Courses of instruction on selected subjects in ophthalmology have been programmed and form part of the data base. A search of the literature retrieval system by single subject, or by a combination of several subjects chosen from the thesaurus, retrieves the appropriate bibliographic citations. The response to the service offered by the Vision Information Center indicates that the center should expand its facilities to satisfy the needs of its clients.

Phoria adaptation to prisms. A cerebellar-dependent response.

Horizontal prism placement in normal subjects results in an apparent change in phoria by an amount equal in power and opposite in direction to the prisms used. However, the measured phoria gradually returns toward the value preceding the placement of prisms. This is termed phoria adaptation. This response was measured in five normal subjects and five patients with cerebellar deficit. The magnitude of the response was significantly reduced in the patient group. Visual acuities and fusional reserves were comparable in the two groups. The mean age was greater, and the stereoscopic acuity decreased, in the patient group. These factors were unlikely to account for the reduced response in patients. The results suggest that the phoria adaptation response in normal subjects depend on the integrity of the cerebellum.

Visual acuities and scotomas after one week levodopa administration in human amblyopia.

The authors previously showed that a single dose of levodopa improves the contrast sensitivity and decreases the size of fixation point scotomas in amblyopic patients. In the present study, they investigated the effect of levodopa after 1 wk of daily administration using a cross-over, double masked design. The decrease of fixation point scotomas was confirmed with automatic static perimetry. An improvement of visual acuity occurred in 70% of the patients after 1 wk of levodopa administration compared to only 22% in the authors' previous study using one single dose. The improvements in visual acuities and visual fields persisted even after the levodopa administration was completed.

Spasmus nutans. A long-term follow-up.

PURPOSE: Nystagmus, head nodding, and anomalous head position are symptoms of spasmus nutans. This disorder appears in early childhood and is thought to be self-limited. However, the visual outcome of patients with spasmus nutans is unclear. The resolution of nystagmus has not been proven with quantitative eye movement recordings. The purpose of this study was to perform long-term follow-up examinations (mean, 5.5 years) of patients with spasmus nutans. METHODS: Ten patients with spasmus nutans were followed up clinically until a mean age of 7 years. Included were quantitative eye and head movement recordings. RESULTS: At their last examination (mean age, 7.1 years), visual acuity in four patients was 20/20 in both eyes, in five patients it was 20/30 or better in at least one eye, and in one patient it was 20/50 in each eye. Three patients had orthotropia with normal stereo acuity. The remaining patients had esotropia, dissociated vertical deviation, amblyopia, or latent nystagmus. All patients had fine, intermittent asymmetric, pendular nystagmus on eye movement recordings. CONCLUSIONS: Good visual acuity can be expected in patients with spasmus nutans; one third have normal stereo acuity. However, subclinical nystagmus persists until at least 5 to 12 years of age.

Treatment of acquired nystagmus with botulinum neurotoxin A.

OBJECTIVE: Acquired nystagmus may cause oscillopsia and in some cases decreased visual acuity. Such symptoms may be debilitating. We evaluated the efficacy of retrobulbar botulinum neurotoxin A in the visual rehabilitation of patients with acquired symptomatic nystagmus. PATIENTS: Adults with acquired nystagmus from multiple sclerosis or brain-stem hemorrhage were recruited for this treatment study. Eligible patients were unable to perform visual tasks that they had performed prior to the onset of the nystagmus. DESIGN AND INTERVENTION: A prospective study evaluated the results of the retrobulbar injection of 25 to 30 U of botulinum neurotoxin A. Patients underwent testing of visual function, including eye movement recordings before and after initial injections. Patients were followed up for changes in their visual function for at least 6 months following the last injection. RESULTS: Six patients (nine eyes) with acquired nystagmus were treated with a series of 17 injections of retrobulbar botulinum neurotoxin A. Each patient had subjective and objective improvement in distance visual acuity following the injection. A reduction in the amplitude of the nystagmus was seen following each of the injections, but the frequency of the nystagmus was generally unchanged. Visual improvement usually lasted no more than 8 weeks. However, improvement persisted for 6 months after injection in two patients with oculopalatal myoclonus. CONCLUSION: Botulinum neurotoxin A transiently improves the visual function of patients with acquired nystagmus. For patients with oculopalatal myoclonus the improvement seems to last longer, about 6 months in two patients.

An improved method of fitting resultant prism in treatment of two-axis strabismus.

A new chart determines resultant prism power and angle when correction of combined horizontal and vertical deviation with a single prism, set at an angle intermediate between horizontal and vertical, is desired. The chart is based on a derivation so weighted as never to permit a vertical error greater than one tenth as large as the associated horizontal error, with use of commercially available sizes of plastic Fresnel-type prisms. This weighting takes into account differences in horizontal and vertical fusional reserves. A compass rose facilitates proper alignment of the prisms.

Bilateral total corneal and conjunctival choristomas associated with epidermal nevus.

A 4-year-old boy had been noted from birth to have bilateral masses obscuring the entire outer portion of the eyes. Systemic findings included mild growth retardation, multiple cortical lesions of the distal metaphyseal ends of the lower extremities, and diffuse skin pigmentation of the right side of the body. The epibulbar lesions were excised; on the right side, there was a thin cornea that necessitated corneal transplantation. The diagnosis of composite epibulbar choristomas associated with linear epidermal nevus was established by pathologic examination. This case report as well as a literature review establish the association of epibulbar choristomas with cutaneous linear nevi of the epidermal and sebaceous types.

Central trochlear palsy.

Historically, the trochlear (IV) nerve has been "neglected" by neurologists and ophthalmologists. However, the reported incidence of trochlear palsy in two large series has more than doubled in the past two decades, indicating increasing awareness of this nerve. Trauma is the most common cause of trochlear palsy, as the trochlear nerve is anatomically more vulnerable to trauma than the other ocular motor nerves. Trochlear palsy can also be caused by vascular and inflammatory diseases, congenital factors, toxic substances and tumors. Diplopia secondary to vertical and horizontal deviation is the most common presentation. The trochlear nerve has a relatively high recovery rate after the underlying cause of injury has been corrected. In this article, the anatomy and physiology of the trochlear nerve are described, and the various etiologies, methods of diagnosis and differential diagnosis of trochlear palsy are reviewed.

Preschool vision screening for amblyopia and strabismus. Programs, methods, guidelines, 1983.

Amblyopia and strabismus, which afflict at least 5% of children, require treatment early in life for best visual results. At present, many such children are treated late or not at all. Mass screening at preschool age, and perhaps ultimately of infants, appears the only viable solution to this problem. To ascertain the present status of preschool screening in the United States, on-site visits, mail questionnaires and telephone interviews were used to study existing preschool vision screening programs at the federal, state and private organization levels. We estimate that, at most, 21% of preschool children receive any form of vision screening. Only two states, Michigan and Minnesota, have legislated requirements for such screening. Several organizations have attempted to establish screening guidelines, with suggestions of specific test and referral criteria. These guidelines are reviewed. The guidelines are of particular interest because screening programs following them typically indicate far lower prevalence rates than most studies indicate actually exist, suggesting that the guidelines result in underreferrals. In order to assess this matter, vision screening methods appropriate for preschoolers or infants, based on current evidence, are reviewed. Stereoscopic testing, utilizing a random dot stereogram format, appears the best instrument available for amblyopia and strabismus screening, but large scale comparative studies of the different test methods are needed to arrive at a final determination. Suggestions are made for the physician interested in initiating preschool vision screening programs.

Ocular choristomas.

Choristomas are congenital lesions representing normal tissue(s) in an abnormal location. They are the most common epibulbar and orbital tumors in children. Epibulbar choristomas affect the cornea, limbus or subconjunctival space, and range in appearance from a small, flat lesion to a large mass filling most of the epibulbar region. Astigmatism is often present. Choristomas may be associated with coloboma, Goldenhar syndrome or epidermal nevus syndromes; those associated with the latter are often bilateral and extensive. Choristomas are occasionally familial. Surgery may be indicated to improve vision or cosmesis, or to impede growth. Although choristomas most commonly involve the epibulbar area, they can affect many areas of the eye and orbit, and often affect more than one area.

Surgical management of oculomotor nerve palsy.

We treated seven patients with unilateral oculomotor nerve palsy by transposition of the insertion of the superior oblique tendon to a point anterior and medial to the insertion of the superior rectus muscle without trochleotomy (Scott procedure). Additionally, large recessions of the lateral rectus muscle of involved eyes and, occasionally, recess/resect procedures of horizontal recti muscles of non-involved eyes were performed. All patients were followed up between one and eight years. Orthophoria in the primary position was achieved and maintained with one operation in four patients. A fifth patient had only a small residual exotropia. In two patients who had aberrant regeneration of the oculomotor nerve, surgery on horizontal recti muscles of the noninvolved eye improved the eyelid position of the involved eye after three operations.

Quantitative eye and head movement recordings of retinal disease mimicking spasmus nutans.

PURPOSE/METHODS: To investigate whether quantitative head and eye movement recordings can distinguish patients with spasmus nutans from patients with retinal diseases mimicking spasmus nutans. A patient with congenital stationary night blindness was followed up for seven years with electro-oculographic eye movement recordings. RESULTS/CONCLUSIONS: Rhythmic head movements and fine, intermittent, asymmetric, disconjugate, high-frequency, out-of-phase pendular nystagmus were recorded. Eye and head movement recordings of patients with congenital stationary night blindness can mimic spasmus nutans.

Treatment of manifest latent nystagmus.

Eight patients with manifest latent nystagmus, as noted by ocular movement recordings, were examined for nystagmus reduction after surgical or optical treatment. Seven of the patients had strabismus. Five patients underwent strabismus surgery, had no tropia postoperatively, and the manifest latent nystagmus converted to latent nystagmus. Four of these five patients subsequently showed improvement in binocular visual acuity. Three patients received optical treatment; one had accommodative esotropia and, with appropriate spectacle correction, the manifest latent nystagmus was converted to latent nystagmus with improved vision. In the other two patients the manifest latent nystagmus lessened after correction with appropriate spectacles; binocular visual acuity of one of these patients improved. The possibility of converting manifest latent nystagmus to latent nystagmus by strabismus surgery is a reasonable surgical goal. In patients with manifest latent nystagmus and strabismus, surgical or optical alignment of the eyes decreases the nystagmus intensity and may also improve binocular visual acuity.

Visual-evoked cortical potentials in dissociated vertical deviation.

It is debatable whether chiasmatic misrouting of temporal optic-nerve fibers (similar to that found in ocular albinism) is also characteristic of dissociated vertical deviation. Pattern appearance, pattern reversal, and diffuse-flash, monocular full-field visual-evoked cortical potentials were recorded from albino and normal human subjects and subjects with dissociated vertical deviation. Pattern appearance was the most reliable stimulus for evaluating lateralization (albino-type misrouting) in adult albino patients, and diffuse-flash stimulation was almost as reliable in children. Pattern reversal was found to be an unreliable indicator. Lateralization was not evident among patients with dissociated vertical deviation, as determined by the three modes of stimulation. Our data supported earlier findings that pattern appearance is the most appropriate technique to detect lateralization. Our findings differed from those of previous reports in demonstrating that reliability of the lateralization phenomenon increases with age up to approximately 15 years. Pattern reversal stimulation was not reliable in patients with horizontal nystagmus.

Ophthalmic examination of infants and children by the pediatrician.

The author offers a logical procedure and philosophy for the pediatrician to use for the examination of infants and children, giving guidelines for proper time periods for examinations and for the extent of the examination.

Costenbader Lecture. Idiopathic infantile nystagmus: diagnosis and treatment.

Current concepts of idiopathic infantile nystagmus are summarized, with special attention to treatment and differential diagnosis of this condition. Advantages of the Anderson procedure over the Kestenbaum procedure are suggested for head turn associated with this condition, and the need for further studies is acknowledged. The importance of the extended slow phase in understanding the waveforms of infantile nystagmus is stressed. Our studies reinforce what I believe to be the natural history of infantile nystagmus, as well as the history of periodic alternating nystagmus. The critical delineation of diagnosing periodic alternating nystagmus is emphasized with respect to the type of operation to avoid overcorrection of head turns in patients with nystagmus. Continued searches for manifest latent nystagmus are important, because that condition is currently the only truly treatable nystagmus. I thank the American Association for Pediatric Ophthalmology and Strabismus for the privilege and honor of presenting the 1997 Costenbader Lecture.

Relationships among visual acuity demands, convergence, and nystagmus in patients with manifest/latent nystagmus.

BACKGROUND: We investigated the role convergence plays in nystagmus dampening, in particular, relationships among visual acuity demands, convergence, and nystagmus. Previously we showed that subjects with idiopathic infantile nystagmus exhibit a range of responses to acuity targets, one of which is nystagmus blockage syndrome. We report herein eye movement responses to acuity targets of patients with manifest/latent nystagmus. METHODS: Fourteen patients, 11 with latent or manifest latent nystagmus and 3 with combined manifest latent with infantile nystagmus, were asked to indicate the direction of the gap in Landolt C optotypes while their eye movements were recorded. RESULTS: The tested patients exhibited various responses to acuity demands: (1) dampening of nystagmus with convergence (i.e., nystagmus blockage syndrome) (5/14 patients), (2) changes in vergence without nystagmus dampening (2 patients), (3) decrease of nystagmus without convergence (2 patients), and (4) little change in nystagmus or vergence (5 patients). In nystagmus blockage syndrome the amount of convergence increased with acuity demands in two of five patients and the convergence duration in four of five patients; nystagmus dampening increased with acuity demands in one of five patients and the blockage duration in four of five patients. CONCLUSIONS: Many, but not all, patients with manifest/latent nystagmus, similar to those with infantile nystagmus, used convergence to dampen their nystagmus. The convergence response tended to increase with acuity demands, but the amount of dampening was idiosyncratic and not predictably related to the measured convergence across patients.

Asymmetry in congenital ocular motor apraxia.

A 10-month-old girl presented with apparently unilateral ocular motor apraxia (OMA). Electro-oculography confirmed an inability to generate a saccade for fixation or in response to an optokinetic or vestibular evoked stimulus to the right. Fixation and optokinetic saccades and vestibular evoked nystagmus were present to the left. Magnetic resonance imaging revealed a small cerebellar vermis but no localizing unilateral abnormality or tumour. Subsequent review of video recordings of 16 children with congenital OMA revealed that 5 demonstrated asymmetry in the generation of fixation saccades. Two of the five also demonstrated asymmetry of vestibular evoked nystagmus, and an additional child had optokinetic asymmetry.

The changes in refractive status following routine strabismus surgery.

The change in refractive status of an eye that has undergone muscle surgery appears to be due to cornea changes. While not all patients are affected, a moderate number will show enough change in astigmatism to cause a decrease in the visual acuity from a few letters to two lines difference. These changes, more commonly an increase in with the rule astigmatism, tend to disappear in time, although in an occasional patient they may persist. Such a change is especially noted when two nonadjacent recti muscles are operated on the same eye. One advantage in operating on the fixing eye is that of allowing a surgically induced amblyopic therapy to continue into the postoperative period. A noncycloplegic or "dry" retinoscopy seems to be a quick and effective way of determining the existence, though not the amount, of such a change in the refractive status.

Skin impedance comparisons of electrodes for electro-oculography.

In an effort to define the most comfortable electrode needing the simplest skin preparation with low and stable skin impedance, we compared the impedance between skin electrodes and Stat-Trace II St-102 EKG electrodes (Niko Med USA, New Brunswick, NJ)--the latter being renamed "dry electrodes" because they are used without electrolyte paste--on 12 normal subjects with two different skin preparations, with and without alcohol. The dry electrodes were found to have lower impedance than the skin electrodes. With each skin preparation the alcohol scored better, 7.2 kOhm vs 16.5 kOhm, respectively, and "no preparation" worse, 13.8 kOhm vs 22.7 kOhm, respectively, (but still acceptable when the dry electrode was used). The dry electrode's impedance was quite stable from the moment of application while the skin electrode's impedance drifted dramatically for 30 minutes. If the dry electrode was halved in area of skin contact, as often is necessary with the nasal electrode in children, the impedance rose proportionally but remained acceptable. We conclude that the new dry electrodes give us improved electro-oculography records and suggest their use, particularly for infants and young children where ease of application and simple skin preparation are particularly important.