Restoration of binocular single vision after long-term fusion disruption

Reversal of severe vergence anomaly associated with convergence insufficiency

Central disruption of fusion refers to a subject's inability to fuse images, resulting in constant diplopia. Severely reduced vergences, or vergence anomalies, producing markedly decreased fusional amplitudes resembling fusional disruption have not been reported previously with convergence insufficiency. We report 3 patients with severe vergence anomalies in the setting of convergence insufficiency.

New facilitation exercise using the vestibulo-ocular reflex for ophthalmoplegia: preliminary report

Objective: To study the effect of facilitation exercises using the vestibulo-ocular reflex on ophthalmoplegia due to brainstem injury.

Design: A single-baseline design (A–B: A without specific therapy, B with specific therapy) across individual subjects.

Setting: Inpatient rehabilitation facility.

Subjects: Eight patients with ophthalmoplegia (total of 15 affected muscles) due to brainstem injury.

Interventions: Basic rehabilitative treatment that included physical therapy, occupational therapy and/or speech therapy for impairments such as hemiplegia, ataxia or dysarthria was administered for two weeks (control treatment). Then, two facilitation exercise sessions (100 times/day, five days/week for two weeks) were administered in addition to the basic rehabilitative treatment for four weeks to the eight patients with ophthalmoplegia. Ophthalmoplegia was evaluated at study entry and at the end of each two-week session. The goal of the facilitation exercises is to facilitate voluntary eye movement using conjugated eye movements in the direction opposite to passive movements of the head.

Main measures: To assess ophthalmoplegia we measured the distance between the internal/external corneal margin and the canthus of the affected eye on images recorded on a video tape recorder.

Results: After the initial two-week basic rehabilitative treatment, the distance between the corneal margin and canthus decreased slightly. Subsequently, after each of the two facilitation exercise sessions, there were significant reductions in the distance between the corneal margin and canthus compared with that at the beginning of the respective facilitation exercise session.

Conclusion: Facilitation exercises significantly improved the horizontal movement of eyes with ophthalmoplegia due to brainstem injury.

Risk factors of persistent diplopia following secondary intraocular lens implantation in patients with sensory strabismus from uncorrected monocular aphakia

PURPOSE

We aimed to compare clinical characteristics between diplopia-free and diplopia-persistent patients after successful strabismus surgery, when patients complained of diplopia following secondary intraocular lens (IOL) implantation after prolonged aphakia accompanied by sensory strabismus.

METHODS

Retrospective review of medical records of patients who complained of diplopia following secondary IOL placement with sensory strabismus after prolonged uncorrected monocular aphakia from isolated ocular trauma was done. We classified patients into two groups according to persistency of diplopia, 6 months after successful strabismus surgery. Clinical characteristics were compared between groups.

RESULTS

A total of 31 patients were included. The diplopia-persistent group showed longer duration of uncorrected aphakia (p = 0.02), less severe corneal astigmatism (p = 0.04), a smaller exodeviation angle (p = 0.02), and more frequent vertical deviation (p = 0.015), extorsion (p = 0.022) and monocular nystagmus (p = 0.028) than the diplopia-free group. In all patients in the diplopia-free group, diplopia could be eliminated prior to strabismus surgery using loose prisms in free space, whereas seven patients in the diplopia-persistent group prior to surgery could not resolve diplopia.

CONCLUSIONS

Our data will be helpful for ocular surgeons in determining whether to insert secondary IOL in prolonged aphakia with sensory strabismus, or whether strabismus surgery will eliminate diplopia that develops following secondary IOL placement in this situation.

Comitant strabismus: Perspectives, present and future

Comitant strabismus is a common condition affecting infants, children and adults. Its impact on the affected patient may be severe resulting in visual loss, lack of binocularity, diplopia, social stigma and multiple corrective surgeries within the affected individual's lifespan. It is therefore important that this prevalent disorder should be better understood. We review the current understanding of the demographics and what is known of the etiology, risk factors and genetics of strabismus. We stress the importance of careful clinical assessment in classifying strabismus, and the common pitfalls in the measurement and pre-operative sensory work-up of the strabismic patient. The fact strabismus is comitant does not indicate it is benign: acute onset of comitant esotropia may be a presenting sign of pontine or cerebellar tumor. Lastly, we review the impact of genetics on our understanding of strabismus. While the causes of many types of congenital incomitant strabismus have been elucidated through careful observation and genetic screening, the genetics of comitant strabismus are more complex and multifactorial. Only through careful study and recruitment of large groups of affected individuals and families can we start to answer the question: why is this group of patients pre-disposed to develop strabismus. Doing so will help identify patients at risk, to spare them from the significant morbidity associated with this common disorder.

Are Orthoptic Exercises an Effective Treatment for Convergence and Fusion Deficiencies?

PURPOSE

To investigate whether orthoptic exercises are an effective way to influence the near point of convergence, fusion range and asthenopic symptoms.

METHODS

Seventy-eight patients met the inclusion criteria of visual acuity 6/9 or better, no history of orthoptic treatment, squint surgery or Meares Irlen syndrome/dyslexia. Information was collected from case records related to diagnosis, near point of convergence, fusion range, prism and cover test measurements and symptoms. Type, duration and frequency of exercises were also recorded. Non-parametric statistics were applied.

RESULTS

Patients ranged in age from 5 to 73 years (mean 11.9). Females outnumbered males (46:32). The diagnoses were: decompensating heterophoria (n = 50) or convergence insufficiency (n = 28: primary 27; secondary 1). Exophoria was more common (n = 65), than esophoria (n = 11) or orthophoria (n = 1). Treatments were aimed at improving near point of convergence and/or reduced fusional reserves. The mean treatment period was 8.2 months. Reduced near point of convergence normalized following treatment in 47/55 cases, and mean near point of convergence improved from 16.6 to 8.4 cm (p = 0.0001). Fusional reserves normalized in 29/50. Fusional convergence improved significantly for those with exodeviation (p > 0.0006). Asthenopic symptoms improved in 65 patients. A reduction in deviation of 5 pd or more occurred in 20 patients.

CONCLUSIONS

Orthoptic exercises are an effective means of reducing symptoms in patients with convergence insufficiency and decompensating exophoria, and appear to target the proximal and fusional components of convergence. Their role in esophoria is unclear and needs further study.

Combined strabismus and lens surgery

BACKGROUND

Simultaneous eye muscle and lens surgery in patients with strabismus and lens abnormalities offers the advantage of avoiding staged surgery.

METHODS

Thirty-three combined strabismus and lens surgeries were performed on 30 patients who ranged in age from 22 months to 91 years. Fifteen of the strabismus procedures were performed for esotropia, 12 for exotropia, 4 for vertical deviations, and 2 for combined vertical-horizontal deviations. Surgical amounts often were reduced to lessen the risk of overcorrection, to minimize anesthetic requirements (when using topical rather than general anesthesia), or to avoiding additional surgery on the contralateral or ipsilateral eye. The intraocular surgeries included cataract extraction without or with posterior chamber intraocular lens, secondary intraocular lens implantation, and YAG laser posterior capsulotomy. In 28 cases, muscle and intraocular surgery was performed on the same eye, and in 5 cases the strabismus surgery was performed on the eye opposite the intraocular surgery.

RESULTS

The average length of postoperative follow-up was 23.2 months (range, 1-94 months). Surgical, anesthetic, and postoperative complications, other than unsatisfactory ocular alignment, were limited to one retinal detachment in a patient with persistent fetal vasculature. Strabismic undercorrections (>12(Delta) of horizontal deviation or >5(Delta) of vertical deviation) occurred in 11 cases (37%). There were no overcorrections. A poor visual response (<20/50) to the intraocular surgery was encountered in 6 patients, all as the result of amblyopia or preexisting vitreoretinal pathology.

CONCLUSIONS

Simultaneous extraocular muscle and lens surgery is an option for patients with strabismus and lens abnormalities. Standard strabismus surgical amounts are recommended.