Is there value in measuring near visual acuity during occlusion therapy for amblyopia?

Introduction: The purpose of this study was to investigate near and distance visual acuity (VA) prior to, during and on completion of occlusion therapy for amblyopia. Method: Fifty-four patients aged 4-7 years (mean 4.9; ±0.44) with untreated strabismic, anisometropic or mixed amblyopia were recruited to the study following refractive adaptation where applicable. All patients underwent conventional occlusion (patching). Uniocular near and distance VA was tested using age and ability appropriate Crowded LogMAR VA tests prior to, during and upon conclusion of occlusion therapy. Results: In amblyopic eyes, there was no significant difference between near and distance VA prior to occlusion therapy with LogMAR Crowded (p = .66; mean distance VA at 3 m = 0.6 LogMAR; mean near VA at 40 cm = 0.58 LogMAR), or with LogMAR Crowded Kay Picture test (p = .78, mean distance VA at 3 m = 0.44 LogMAR; mean near VA at 33 cm = 0.46 LogMAR;). No significant difference was found between near and distance VA at any visit during occlusion therapy, or on completion of occlusion therapy with LogMAR Crowded (p = .86, mean final distance VA at 3 m = 0.266 LogMAR; mean final near VA at 40 cm = 0.25 LogMAR) or LogMAR Crowded Kay Pictures (p = .74, mean final distance VA at 3 m = 0.16 LogMAR; mean final near VA at 33 cm = 0.16 LogMAR). There was no significant difference in the VA of the fellow (non-amblyopic) eyes prior to and on completion of occlusion therapy with LogMAR Crowded at distance (3 m) or near (40 cm) (p = .05, p = .40 respectively); or with LogMAR Crowded Kay Pictures at distance (3 m) or near (33 cm) (p = .89, p = .35 respectively). Discussion: Improvement in VA of amblyopic eyes did not significantly differ between near and distance testing proximites at any point during the course of occlusion therapy for amblyopia in our study. These findings may aid clinicians with appropriate test selection and help with clinical time pressures. Where patient concentration does not allow for uniocular distance vision, uniocular near vision may be used to diagnose amblyopia, and vice versa. This could prevent delay in the treatment of amblyopia.

Analysing nystagmus waveforms: a computational framework

We present a new computational approach to analyse nystagmus waveforms. Our framework is designed to fully characterise the state of the nystagmus, aid clinical diagnosis and to quantify the dynamical changes in the oscillations over time. Both linear and nonlinear analyses of time series were used to determine the regularity and complexity of a specific homogenous phenotype of nystagmus. Two-dimensional binocular eye movement recordings were carried out on 5 adult subjects who exhibited a unilateral, uniplanar, vertical nystagmus secondary to a monocular late-onset severe visual loss in the oscillating eye (the Heimann-Bielschowsky Phenomenon). The non-affected eye held a central gaze in both horizontal and vertical planes (± 10 min. of arc). All affected eyes exhibited vertical oscillations, with mean amplitudes and frequencies ranging from 2.0°-4.0° to 0.25-1.5 Hz, respectively. Unstable periodic orbit analysis revealed only 1 subject exhibited a periodic oscillation. The remaining subjects were found to display quasiperiodic (n = 1) and nonperiodic (n = 3) oscillations. Phase space reconstruction allowed attractor identification and the computation of a time series complexity measure-the permutation entropy. The entropy measure was found to be able to distinguish between a periodic oscillation associated with a limit cycle attractor, a quasiperiodic oscillation associated with a torus attractor and nonperiodic oscillations associated with higher-dimensional attractors. Importantly, the permutation entropy was able to rank the oscillations, thereby providing an objective index of nystagmus complexity (range 0.15-0.21) that could not be obtained via unstable periodic orbit analysis or attractor identification alone. These results suggest that our framework provides a comprehensive methodology for characterising nystagmus, aiding differential diagnosis and also permitting investigation of the waveforms over time, thereby facilitating the quantification of future therapeutic managements. In addition, permutation entropy could provide an additional tool for future oculomotor modelling.

Amblyopia treatment and quality of life: the child's perspective on atropine versus patching

Background: The impact on children of patching versus atropine treatment for amblyopia was assessed using children's perspective Health-Related Quality of Life (HRQoL) scores in 5 to 7-year olds. Methods: Forty-six children on the threshold of commencing either patching or atropine treatment for amblyopia were recruited. Treatment was prescribed for uniocular amblyopia of visual acuity (VA) 0.2 logMAR or worse. After four weeks of their chosen treatment, each child completed the Child Amblyopia Treatment Quality-of-Life Questionnaire (CAT-QoL). The Pediatric Quality of Life Inventory (PedsQL™), Young Child (5-7) Self-Report version, was completed before and after four weeks of treatment. Quality of life scores were compared between the two treatment groups. Results: Sixty-one percent (n = 28) of participants were male and 56.5% (n = 26) were white British. The CAT-QoL has a range of 0-16, with 16 being the worst quality of life. No significant difference was found between the patching group (n = 30, mean age 69.7 months) and the atropine group (n = 16, mean age 69.3 months) for CAT-QoL quality of life scores (Patch median = 6.3, Atropine median = 5.6, U = 199, p = .341, 95% CI of the median difference of -2.3 to 0.9). The Young Child (5-7) Self-Report version of the PedsQL™ has a 'total score' range of 0-100, with 0 being the worst quality of life. There was also no significant difference in PedsQL™ quality of life total scores (Patch median = 80, Atropine median = 83.33, U = 239.5, p = .991, 95% CI of the median difference -13.33 to 10) after four weeks of treatment. Conclusion: Amblyopic children reported that patching and atropine treatments did not have a significant impact on their quality of life. Patching and atropine should continue to be offered as first-line treatments for amblyopia, as children appear to tolerate both well and do not favor one over the other.

A Case Report of Progressive Brown Syndrome?

Aim:

To report an unusual case of progressive Brown syndrome and the successful surgical treatment.

Methods:

A 42-year-old male with a documented 14-year history of progressive Brown syndrome is presented. To improve diplopia symptoms an ipsilateral superior oblique (SO) 7 mm silicone tendon spacer and a contralateral 3 mm superior rectus (SR) recession were performed.

Results:

The surgical procedure was successful in reducing the primary position deviation (preoperative 30ΔLHoT 7ΔLXT; one month post surgery 3ΔLHo; one year post surgery 7-8ΔLHo 1-2ΔE) and eliminating the abnormal head posture (AHP). Diplopia was only reported on elevation and depression following surgery.

Conclusion:

This case of Brown syndrome is unusual as it was progressive and had a documented history over a number of years prior to surgery. Surgical treatment of Brown syndrome is rarely required, but in this case was successful in improving the patient’s diplopia and AHP.

The Provision of Patient Information about Nystagmus

Aims

The aims of this study were to evaluate the current provision of patient information about nystagmus in orthoptic clinics in the UK and Ireland and to develop a standardised information pack about nystagmus.

Methods

A questionnaire was circulated to orthoptists in the UK and Ireland asking whether they had information to provide to patients with nystagmus, what was included in this information and how it could be improved. Orthoptists were also asked what should be included in a standardised information pack about nystagmus.

Results

Two hundred and thirty three orthoptists completed the questionnaire. One-third of responding orthoptists did not have information to provide to patients with nystagmus. Most reported the information available to them included details of support services and physical symptoms. Including information about living with nystagmus at different ages and long-term prognosis were the most common suggestions to improve information about nystagmus. More than half of orthoptists selected all the suggested topics to be included in a standardised information pack, with support services and long-term prognosis most frequently selected.

Conclusions

Only 67% of responding orthoptists had information about nystagmus to give to patients or their families. Ways to improve the current information and content considered important by orthoptists were taken into account to create a nystagmus information pack, which is now available online.

Surgery to Treat Residual Acquired Excyclotropia without Changing the Primary Position Vertical Deviation: A Case Report

AIM

To describe the surgical management and long-term outcome of a case of symptomatic residual acquired primary position excyclotropia, without changing the primary position vertical deviation.

METHODS

This case report describes ipsilateral half tendon width transpositions of the left superior rectus temporally and inferior rectus nasally, combined with right inferior rectus posterior fixation suture at 11 mm.

RESULTS

Three days postoperatively, the transposition procedure produced a 10° cyclotorsional change in primary position, resulting in 5° of incyclotorsion (double Maddox rod). Six weeks postoperatively, the incyclotorsion regressed to 1° (synoptophore) and a central field of binocular single vision (BSV) (90° horizontally and 60° vertically) was demonstrated without an abnormal head posture. Fifteen months postoperatively, 1° primary position incyclotorsion (Torsionometer) and the central field of BSV remained stable. The primary position vertical deviation was changed by 1 prism diopter and no V pattern was induced.

CONCLUSION

In our case, ipsilateral half tendon width horizontal transpositions of the vertical recti achieved satisfactory correction of excyclotorsion and restored BSV without significantly changing the primary position vertical deviation. The result was stable 15 months postoperatively.

The incidence and visual acuity outcomes of children identified with ametropic amblyopia by vision screening

PURPOSE

To determine the incidence of ametropic amblyopia within a vision screening program's population and report the visual acuity outcomes of children identified with the condition.

METHOD

The medical records of children who underwent vision screening as their first assessment at 4-5 years of age between September 1, 2005 and August 31, 2006, were retrospectively reviewed. Children referred with ≤0.30 logMAR in each eye with at least 1 year of follow-up had their hospital notes reviewed and data on final visual acuity, refractive error, and follow-up period collected.

RESULTS

A total of 33 children identified as having ametropic amblyopia with a follow-up of at least 1 year. The incidence of ametropic amblyopia was 2%-3.2%, depending on the definition used. The mean visual acuity achieved after treatment was 0.12 logMAR, which is significantly less than the age-appropriate mean of 0.00 logMAR (P < 0.01).

CONCLUSIONS

Ametropic amblyopia responds to treatment, but most children demonstrate persistent reduced visual acuity at age 7 years. The incidence of ametropic amblyopia within a routine vision screening population shows that significant numbers fail to self-present.

Decompensating esophoria as the presenting feature of myasthenia gravis

Myasthenia gravis is a disease in which antibodies directed at nicotinic acetylcholine receptors are produced, leading to a deficiency of acetylcholine receptors at the neuromuscular junction. This results in impairment of muscular excitation, which appears clinically as fatigable muscle weakness. Weakness of the extraocular muscles occurs in nearly 90% of all myasthenics at disease onset, with ptosis being the most common presenting feature. Myasthenia gravis affecting one or a combination of the extraocular muscles without ptosis is less common; however, cases such as bilateral internuclear ophthalmoplegia without ptosis have been described in the literature. The authors present a case in which decompensating esophoria was the presenting feature of myasthenia gravis.