Binocular diplopia in unilateral aphakia: the role of botulinum toxin

Role of botulinum toxin A in treatment of intractable diplopia

PURPOSE

To evaluate the effect of botulinum toxin A (BTXA) in patients with intractable diplopia related to intracranial problems or long-term interruption of fusion due to cataract or uncorrected aphakia and to identify the group of resistant cases who have no potential to fuse the two images.

METHODS

The medical records of patients seen by the senior author (SBÖ) over a period of 20 years were reviewed retrospectively to identify those who underwent BTXA treatment for intractable diplopia. All cases had horizontal and/or vertical deviations. The diagnostic criterion was persistence of diplopia in free space despite neutralization of the deviation by prisms or synoptophore. BTXA was injected into the appropriate extraocular muscle to control the deviation in the identified patients.

RESULTS

A total of 22 patients were identified: 13 developed intractable diplopia following head trauma, intracranial surgery, or stroke; 9 had a history of binocular sensory deprivation due to traumatic cataract or uncorrected aphakia. The duration of sensory deprivation ranged from 2 to 41 years. BTXA was injected into the appropriate extraocular muscle(s). Diplopia resolved completely in 14 patients, resolved incompletely with short-term single vision in 3 cases, and persisted in 5 patients despite correction of the deviation by BTXA.

CONCLUSIONS

Our results suggest that BTXA offers the advantage of a temporary decrease of the deviation without altering image quality that allows the visual system to recover fusion under real-life conditions. Permanent treatment with surgical correction of the deviation should be reserved for those who achieve fusion during the orthotropic period provided by BTXA.

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.

Diplopia following cataract surgery: a review of 150 patients

AIM

To study the motility pattern, underlying mechanism, and management of patients who complained of double vision after cataract surgery.

METHODS

A retrospective case note analysis of 150 patients presenting with diplopia after cataract surgery to an orthoptic clinic over a 70-month period. Information was retrieved from orthoptic, ophthalmological, and operating room records.

RESULTS

A total of 3% of patients presenting to the orthoptic clinic had diplopia after cataract surgery. We grouped these according to the underlying mechanisms which were: (1) decompensating pre-existing strabismus (34%), (2) extraocular muscle restriction/paresis (25%), (3) refractive (8.5%), (4) concurrent onset of systemic disease (5%), (5) central fusion disruption (5%), and (6) monocular diplopia (2.5%). Twenty per cent of the patients could not be categorised with certainty. After infiltrational anaesthesia, extraocular muscle restriction/paresis was the commonest presentation, while decompensation of preexisting strabismus was commonest with topical anaesthesia.For the 150 patients seen, prisms were the commonest form of treatment prescribed (64%) either in isolation or in combination with other treatment, including surgery (19%). Convergence and divergence insufficiency/paresis patterns were also common. A changing motility pattern was noted in some patients who had early documentation, with increasing comitance over time (spread of comitance). Partial resolution made it difficult to clearly identify the underlying mechanism in patients with late documentation.

CONCLUSION

Double vision is a troublesome complication of otherwise successful cataract surgery. The use of topical anaesthesia does not abolish this surgical risk.

Exotropia secondary to vitreous hemorrhage

BACKGROUND

Diplopia after cataract surgery has been reported by several authors, but diplopia after recovery from vitreous hemorrhage (VH) has not been described.

METHODS

We examined eight patients with manifest exotropia and binocular diplopia after recovery from dense VH by vitreous surgery. VH was bilateral in three patients and unilateral in five, and lasted for an average of 7.7 years.

RESULTS

Visual acuity before vitrectomy ranged from 20/200 to light perception; that after vitrectomy ranged from 20/20 to 20/60. Exotropia was present in all patients after vitrectomy. Additionally, seven out of eight patients had vertical strabismus with an average deviation of 6 prism diopters (delta). Fusion was confirmed in four patients with an average amplitude of 13 delta. Four patients underwent horizontal strabismus surgery. Fusion was present in two before strabismus surgery and in all four after surgery; however, unstable diplopia persisted in three of the four after surgery.

CONCLUSION

Diplopia after vitrectomy for longstanding VH may occur due to fusion impairment comparable to that occasionally seen after surgery for traumatic cataract.

Acquired central fusion disruption following cataract extraction

Central sensory and motor fusion of images, once established, is usually maintained throughout life. Under certain circumstances, this ability may be lost. This gives rise to the syndrome known as horror fusionis, or acquired disruption of central fusion. We report the development of central fusion disruption in three patients with uniocular mature senile cataract. We postulate that this is the result of prolonged sensory deprivation in the cataractous eye. The loss of fusion results in a particularly troublesome type of intractable diplopia, characterized by the inability to either fuse or suppress images. To the best of the authors' knowledge, this is the first report of central fusion disruption following cataract surgery for senile cataract.