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PubMed1980

An unexpected role for normal accommodative vergence in strabismus and amblyopia.

Accommodative vergence was measured using the Müller experimental paradigm in which target movement along the line of sight of the viewing eye results in large movement of the fellow (covered) eye. Our paper demonstrates an unexpected predominance of accommodative vergence over disparity vergence in patients with constant strabismus amblyopia, intermittent strabismus, and amblyopia without strabismus. Comparison of accommodative vergence responses in these patients with responses from normal subjects using symmetrical and asymmetrical targets under binocular and monocular conditions established the normal character of the patients' accommodative vergence and the absence of disparity vergence in most of them. The intermittent absence of disparity vergence in certain of our patients--some with surgically corrected strabismus, some with moderate amblyopia, and some with amblyopia treated with orthoptics--raises questions of clinical and neurophysiological interest. Preliminary results on the effects of amblyopia on accommodative responses are also presented.

Accommodation, Ocular↗

PubMed1982

Use of eye movement auditory biofeedback in the control of nystagmus.

Eye movement auditory biofeedback was used in weekly training sessions to control nystagmus in five adult patients. Within the 1st hr of training, all patients were able to reduce nystagmus. Average maximum group reduction of nystagmus amplitude, peak slow-phase velocity, and frequency achieved during training with auditory biofeedback was 82, 86, and 34%, respectively. At periodic intervals during training, audio information was withheld and patients were able to maintain reduced nystagmus for several minutes. In addition, patients were able to reduce nystagmus upon command without audio cues but with conscious effort while engaging in conversation and other tasks with the experimenters. Visual acuity improvement with conscious patient effort to control nystagmus but without auditory biofeedback averaged 10% Snell-Sterling. One of two patients who returned for post-training reevaluation was able to reduce his nystagmus quickly without auditory biofeedback to 50% of the pretraining level, and both patients were able with the aid of auditory cues to reduce their nystagmus rapidly to the level achieved during training. In addition to the improvement in vision, cosmetic and psychological benefits accrued. Eye movement auditory biofeedback should be considered in the treatment of nystagmus, either alone or in conjunction with orthoptic and/or surgical procedures.

Acoustic Stimulation↗

PubMed1984

Cortical indices of impaired ocular accommodation and associated convergence mechanisms.

The accommodative and fusional vergence mechanisms were examined electrophysiologically in a juvenile suffering from a severe reduction in focusing ability. We used the visually evoked response (VER) to diagnose the accommodation-vergence insufficiency. The procedure is shown to be effective for monitoring longitudinally the ability of simple orthoptic techniques to restore normal accommodative function.

Accommodation, Ocular↗

PubMed1985

Results of surgical treatment of intermittent divergent strabismus.

Inasmuch as surgery is often suggested as the primary treatment for intermittent exotropia, we undertook an extensive literature search to ascertain the outcome of this treatment. Surprisingly, only 22 papers were located which gave presurgical and postsurgical results for intermittent exotropia using reasonably clear success criteria. Many other papers were located but were excluded because they either failed to state the criteria used, lumped exotropia and esotropia together in their reported successes, or used orthoptics along with surgery. The total number of cases reported in the 22 acceptable papers was analyzed in terms of four levels of success to permit comparison across studies. These four levels were: functional success, motor alignment, cosmetically acceptable, and unsuccessful (no change or worse). The data are tabulated and summarized.

Evaluation Studies as Topic↗

PubMed1987

Performance of amblyopic children on printed contrast sensitivity test charts.

Forty consecutive amblyopic patients between the ages of 3 and 12 years attending the Orthoptic Clinic for assessment and treatment were tested on the AO Contrast Sensitivity System [Arden grating test (AGT)] and the VISTECH Contrast Sensitivity Charts. Recordings were unsuccessful in more than 50% of these patients on both test systems. Of those who could successfully complete the AGT, false negative results were noted in 62.5% of the amblyopic eyes and false positive results were found in 25% of the normal fellow eyes. On the near VISTECH chart, all normal and amblyopic eyes produced results that were outside the specified limit of normality. On the distance VISTECH chart, 25% of the normal fellow eyes gave false positive results and 25% of the amblyopic eyes gave false negative results. From these findings, it is doubtful whether either test system has a role in the routine clinical assessment of amblyopia.

Amblyopia↗

PubMed1987

Efficacy of vision therapy in amblyopia: a literature review.

In this paper the major optometric, ophthalmologic, and orthoptic literature on the efficacy of vision therapy for amblyopia has been surveyed. Over the past four decades there are many examples of the successful treatment of amblyopia in the form of well documented individual case reports or large sample studies. Although occlusion of the dominant eye has been applied universally, there are some instances of the successful use of minimal occlusion combined with extensive visual-motor therapy. Overall, the results of the literature review strongly support the use of active vision therapy as an integral part of the clinical treatment of amblyopia.

Amblyopia↗

PubMed1988

Imbalanced adaptation of accommodation and vergence produces opposite extremes of the AC/A and CA/C ratios.

It is customary to describe abnormal interactions between accommodation and convergence according to the Duane-White classification of convergence excess and insufficiency or divergence excess and insufficiency. However, recent studies indicate that these extremely high and low categories of accommodative vergence may result from adaptive disorders of accommodation and convergence. The AC/A ratio is shown in this paper to vary inversely with adaptability of accommodation and to vary directly with adaptability of vergence. Extremely high AC/A ratios can result from an imbalance in which vergence adapts readily to prism, whereas accommodation does not adapt to minus lenses. Similarly, extremely high values for convergence accommodation (the CA/C ratio) are observed when there is robust adaptation of accommodation to lenses and little adaptation of vergence to prism. Furthermore, in these extreme cases the AC/A and CA/C ratios tend to be inversely related. For example, abnormally high AC/A ratios are often accompanied by extremely low CA/C ratios and vice versa. These observations suggest that equalizing the adaptability of accommodation and vergence with orthoptics may prove to be an effective means of restoring the AC/A and CA/C ratios to normal values.

Accommodation, Ocular↗

PubMed1999

Improvement of visual function in an adult amblyope.

PURPOSE: In this case report, the efficacy of occlusion therapy was investigated in a strabismic amblyope above the currently accepted age for treatment. Success was assessed not simply by a change in visual acuity, but by examining a number of parameters which relate to both sensory and motor aspects of visual function. METHODS: As well as routine orthoptic and optometric evaluation, additional tests were administered as follows: high and low contrast LogMAR Crowded Acuity, repeat letter acuity, and hyperacuity measurements. RESULTS: A functional loss in each of the tests used was demonstrated, and occlusion therapy appeared to improve all aspects of the amblyopia, with a significant difference in pre- and post-therapy results. CONCLUSIONS: The results of this study suggest that: (1) occlusion therapy can produce substantial improvements in visual function in adult amblyopia; (2) many aspects of visual function can improve beyond the traditional critical periods for development in amblyopia; and (3) with good patient compliance and cooperation, age should not be the critical factor in the initiation of treatment for amblyopia.

Adult↗

PubMed1998

Diplopia following transconjunctival blepharoplasty.

The resurgence of popularity of the transconjunctival approach to lower eyelid fat removal as a component of cosmetic blepharoplasty has been highlighted by a number of publications in recent years. There has been, however, minimal discussion in the literature of the complications of this procedure. Although the mechanism of muscle injury is similar in transcutaneous and transconjunctival surgery, there is a much more direct route to the inferior extraocular musculature via the latter approach. Herein, we present a series of six patients with diplopia status post-transconjunctival lower eyelid blepharoplasty referred to the Manhattan Eye, Ear, and Throat Hospital for evaluation. Transconjunctival lower lid blepharoplasty was performed as a primary procedure in four patients and as a secondary procedure following transcutaneous blepharoplasty in two patients. Patients were evaluated with ocular examination and orthoptic measurements. Magnetic resonance imaging was obtained in two cases. The inferior rectus and inferior oblique muscles were found to be equally injured in these cases (4 of 6), and the lateral rectus was encountered in one case. Two patients required strabismus surgery to correct their diplopia, whereas four patients improved with observation alone. The possible etiologies of postoperative diplopia following transconjunctival lower lid blepharoplasty are manifold. Mechanisms of extraocular muscle injury may include intramuscular hemorrhage and edema, cicatricial changes within the muscle, and accidental incorporation of extraocular muscle in closure of orbital septum. Avoidance of these complications is probably best achieved through intimate understanding on the part of the surgeon of eyelid anatomy from the transconjunctival perspective.

Adult↗

PubMed1996

Graft-infiltrating cells in rats receiving orthotopic semiallogeneic small intestine transplantation with portal or systemic venous drainage.

The effect of alterations in venous drainage, from either ivc to portal vein (pv), along with peritransplant systemic (ivc) or portal (pv) venous alloimmunization with irradiated semiallogenic cells, on cell subset recovery in lymphoid organs of Lewis rats receiving orthoptic small bowel allografts (from LewisXBrown Norway) F1, LBNF1) was examined. Combined portal, venous drainage and alloimmunization has been reported to increase graft/recipient survival in this model. FACS analysis using monoclonal antibodies specific for different lymphocyte subsets was performed on cell suspensions of peripheral (P) and mesenteric (M) lymph node (LN), small bowel intraepithelial lymphocytes (SBIEL), and Peyer's patch (PP) lymphocytes on days 2 and 8 posttransplantation. Donor cell contributions to these cellular analyses were estimated by comparison of FACS staining with polyclonal anti-Lewis or Lewis anti-LBNF1 antibodies. Control animals received syngeneic grafts. In both syngeneic and semi-allogenic transplants with pv or ivc drainage there was no consistent difference in cell subsets from in PLN compared with those of control nongrafted rats. Approximately 50% to 60% of these cells were alphabetaTcR+ with a CD4+/CD8+ ratio of 3-4:1 and a (CD4++CD8+)/alphabetaTcR+ ratio of 1:1. Some 5% to 12% ED3+ cells were also present. In IEL, MLN, and PP by contrast, there were significant differences in cells recovered from rats with ivc vs. pv drainage of grafts. The most striking changes reflected a decreased CD4+/CD8+ and alphabetaTcR+gammadeltaTcR+ cells in these tissues in rats predestined to show prolongation of allograft survival (ivc vs. pv injected IEL CD4/CD8+ ratios and alphabetaTcR+gammadeltaTcR+ ratios 1.0, 0.7 and 5.0, 1.0, respectively. These data are consistent with a proposed role for such gammadeltaTcR+ cells in the local regulation of graft rejection.

Animals↗

PubMedDate not supplied

The ophthalmologist's role in multidisciplinary assessment of developmentally handicapped children.

Among 200 children who had received routine ophthalmic and orthoptic examinations as part of their evaluation by a multidisciplinary assessment team, it was found that there was a high incidence of ocular defects. These defects included refractive errors (98 children), squint (74 children), nystagmus (15 children), cataract, retinopathy and optic atrophy. This high incidence of ocular defects emphasized the need for the routine ophthalmic examination of developmentally handicapped children in order to detect and treat ocular conditions which might otherwise have gone undetected, and enabled the visual sense of these children to be evaluated in relationship to their general development.

Blepharoptosis↗

PubMedDate not supplied

Visual problems in the handicapped child.

The importance of carrying out a preliminary examination of vision and eye movements in all handicapped is stressed. In any case of doubt a full ophthalmological and orthoptic examination is essential and is best carried out in the congenial environs of a District Handicap Centre. Eight hundred and ninety-three children with a wide variety of handicaps were seen at the Leeds Regional Child Assessment Centre between 1972 and 1977, and 324 were found to have a visual or visuomotor defect. The types of defects are discussed under headings which describe the main handicap.

Autistic Disorder↗

PubMed1983

An evaluation of plasma exchange for Graves' ophthalmopathy.

Eighteen patients with ocular manifestations of Graves' disease were treated by plasma exchange. Detailed clinical, ophthalmological and orthoptic assessments were made including computerized axial tomography and A + B scan ultrasound of the orbits. Seventeen different ocular parameters were separately rated for each patient. The changes recorded were small, statistically insignificant, and no patient was cured of ocular disease. There were no significant correlations between the ocular changes recorded and age, sex, duration of ophthalmic symptoms, the presence of thyroid antibodies, the number of exchanges, or the concurrent administration of azathioprine.

Adult↗

PubMed1993

Parental cigarette smoking and tonsillectomy in children.

The deleterious effects of parental smoking on the upper respiratory tracts of children are becoming increasingly recognized. This study examines the effect of parental smoking on the frequency of tonsillitis and incidence of tonsillectomy in children. A group of children being admitted for tonsillectomy and a control group of children from an orthoptic clinic were studied. Details recorded about the children included a history of tonsillectomy and the number of courses of antibiotics taken for sore throats in the previous 12 months. Parents were questioned about their smoking habits. A marked and statistically significant association has been found between the incidence of tonsillectomy in children and parental smoking in the home environment. There was a higher frequency of attacks of tonsillitis requiring antibiotic treatment in those children whose parents smoked. This effect may be mediated by altered oropharyngeal flora, mucociliary dysfunction, increased cross infection or a combination of these. If parents are encouraged to stop smoking there will be a reduction in tobacco smoke levels in the home environment and this should lead to a fall in both the incidence of tonsillitis and the need for tonsillectomy in their children.

Adult↗

PubMed1998

Patterns of glaucoma medication use in urban and rural Victoria.

PURPOSE: The purpose of the present study was to describe patterns of glaucoma medication use among people who self-report a history of glaucoma in a population-based study of age-related eye disease. METHODS: The present study was comprised of a population-based cluster stratified sample of 5000 Victorians aged 40 years and older. Participants completed an interview regarding demographic characteristics, medical history and use of medications. Participants also completed orthoptic and dilated fundus examinations, including measurement of intra-occular pressure (IOP) and visual fields. Glaucoma history and use of glaucoma medication was self reported. Glaucoma disease status was confirmed by a specialist consensus group. RESULTS: The most common glaucoma medications used were beta-adrenoceptor blocking agents (63%), followed by sympathomimetics (18%) and cholinergic agents (16%). There were no differences in glaucoma medication use by gender, age, years since diagnosis, rural or urban residence or a history of glaucoma surgery. Among participants using medication, 16.1% exceeded 21 mmHg IOP. CONCLUSION: The high prevalence of the use of beta-adrenoceptor blocking agent medication reflects the shift from the use of pilocarpine over the past 20 years. The prevalence of IOP greater than 21 mmHg highlights the difficulty in managing high IOP.

Adrenergic beta-Antagonists↗

PubMed1998

Development of visual function in hemihydranencephaly.

This study reports on the findings of longitudinal follow-up of visual function in a 12-year-old girl affected by congenital right hemihydranencephaly. This extremely rare unilateral brain malformation allowed the authors to gather new information on neuronal plasticity and functional compensations of the visual system across a period of 10 years. An extension of the preserved right visual hemifields above the middle line and strategical eye or head positions developed to increase visual functions are discussed. In addition, ophthalmological and orthoptical findings, as well as the development of monocular grating and linear acuity, are described.

Child↗

PubMed2006

The Mallett Fixation Disparity Test: influence of test instructions and relationship with symptoms.

Fixation disparity is a minute ocular misalignment under conditions of binocular single vision and is typically detected in primary eye care practices in the UK using the Mallett Unit Fixation Disparity Test. This instrument creates natural viewing conditions, when the patient's binocular system is fused using both central and peripheral fusion locks. This allows the examiner to determine the minimum prism power that eliminates the fixation disparity: the associated phoria or aligning prism. The spherical power that eliminates the fixation disparity, the aligning sphere, can also be determined. The near Mallett Unit Fixation Disparity Test has been shown to have good sensitivity and specificity for detecting symptomatic heterophoria. Cases of decompensated heterophoria tend to have a fixation disparity and the aligning prism or aligning sphere is a good indicator of the correction that will render the heterophoria compensated. The purpose of this study was, for the first time, to investigate the effect of test instructions on the results of the Mallett Unit Fixation Disparity Test. In study 1, we surveyed and observed practitioners to determine the instructions that are typically used. In study 2, we compared results obtained with this "standard" method of questioning with a more "specific" form of questioning that has been suggested in the literature. The participants for study 2 were 105 patients aged 7-70 years who were randomly selected from those attending a community optometric practice. Significantly different results were obtained with the two sets of instructions. The specific form of questioning revealed more cases of fixation disparity and the results with this method showed a better correlation with symptoms. This only held for near vision: for distance vision, symptoms were not significantly correlated with the presence of fixation disparity. This agrees with previous work with the Mallett unit, which showed a significant relationship with symptoms only at near. We also found that patients with more severe symptoms had greater degrees of aligning prism. Our study supports previous work indicating that the Mallett unit is a useful tool for detecting symptomatic heterophoria at near. However, we found that the testing method is important: patients need to be asked not just whether the nonius strips are aligned but also whether one or both of the strips ever moves. More research is needed to investigate the significance of precise test instructions in other optometric and orthoptic tests.

Adolescent↗

PubMed1995

Do we have optimal screening limits in Sweden for vision testing at the age of 4 years?

The purpose of this study was to evaluate the Swedish screening criteria for referral of children to ophthalmic care after visual acuity testing at the age of 4 years. The screening limit has generally been 0.8. To what extent do children with 0.65 in each eye (0.65/0.65) or 0.65 in one and 0.8 in the other (0.65/0.8) at the age of 4 years have visual defects needing early treatment? Sixty-three children who had failed screening underwent orthoptic and ophthalmologic evaluation. Twenty-four patients (38%) saw 0.65/0.65 or 0.65/0.8 and were studied further. None of them had manifest strabismus. Refractive errors were minor except in 2 patients who had significant hyperopia. Twenty-two of these 24 patients returned for reevaluation at the age of five years and that time 18 of them saw 0.8 or more without treatment. Our findings suggest that children with visual acuity of no less than 0.65 and no more than one line's difference between the eyes at 4 years of age seldom have visual defects needing treatment.

Child, Preschool↗