Convergence Excess Esotropia: A Proposed New Classification and the Effect of Monocular Occlusion on the Ac/A Ratio

Garretty, Tess

doi:10.3928/01913913-20100118-03

Cited by 10 publications

(5 citation statements)

References 4 publications

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“…It is postulated that tenacious fusion masks the true distance angle of deviation in many patients with convergence excess in a similar way as described by Kushner 7 and Rosenfield et al 8 in intermittent exotropia. The author's previous paper investigating convergence excess esotropia 17 suggested two subcategories of convergence excess accommodative esotropia:…”

Section: Discussionmentioning

confidence: 99%

Convergence excess accommodative esotropia: a descriptive review of patients presenting over a period of 10 years

Garretty

2011

British and Irish Orthoptic Journal

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Aim: Convergence excess accommodative esotropia describes an esotropia on accommodation at near fixation that is controlled to an esophoria/orthophoria at distance fixation with binocular single vision. Sixty-four cases have presented to the Leeds Teaching Hospitals NHS Trust over the last 10 years. This descriptive paper outlines the clinical characteristics of this cohort of patients. Methods: Information was reviewed regarding all children diagnosed as having convergence excess accommodative esotropia entered onto a departmental database between 1999 and 2009. Results: Only 3 children complained of diplopia at presentation. The mean refractive error of the group was right þ2.90DS and left þ2.80DS. The median angle of deviation was 25 D BO at 1/3 m and 4 D BO at 6 m. The mean Ac/A ratio using the gradient method was 6:1 at 1/3 m and 10:1 at 6 m. The angle of deviation was found to be altered by a period of monocular occlusion and prism adaptation. Twenty per cent of children required occlusion for amblyopia. Nine per cent of those with convergence excess were found to decompensate to constant esotropia with time. Conclusions: Testing distance, a period of monocular occlusion and prism adaptation have been shown to alter the angle of deviation and the Ac/A ratio in convergence excess accommodative esotropia. Similarities between convergence excess and fully accommodative esotropia are outlined.

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Section: Discussionmentioning

confidence: 99%

Convergence excess accommodative esotropia: a descriptive review of patients presenting over a period of 10 years

Garretty

2011

British and Irish Orthoptic Journal

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“…5 Garretty 16 reported an annual incidence in Leeds of six new cases per year (city population ¼ 443 000). Kutschke and Keech 17 measured the gradient AC/A ratio in 62% of their DND cases.…”

Section: Hypermetropic Undercorrectionmentioning

confidence: 99%

Distance–near disparity esotropia: can we shrink the gap?

Burke

2014

Eye

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Distance-near disparity esotropias are a group of heterogenous usually acquired strabismus disorders, where the angle of misalignment at near exceeds that at distance by 10 prism diopters or more, where the accurate correction of refractive errors and ambylopia are important early objectives. These aetiologically diverse entities respond non-uniformally to strabismus surgery and bifocals. The management challenge is one of 'shrinking' the disparity so that the affected individuals can develop and comfortably maintain binocular single vision and/or optimal alignment. Surgical procedures have continued to evolve but none of the current operative procedures are superior for all patients. Subclassifying this strabismus and highlighting publication data from more homogenous clinical series may assist with the optimisation of future management and treatment outcomes.

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“…Kushner 11 further reported that a longer period of sustained occlusion prior to measurement significantly altered the ratio, which therefore changed the classification of the patient's condition. The use of monocular occlusion in this way has also been investigated in relation to CXS by Garretty,14 who found monocular occlusion prior to measurement of the AC/A ratio resulted in two clinically and statistically distinct groups. The conclusion was that CXS could be sub-categorised in a similar way to IDEX.…”

Section: Specifics Of Testing Techniquesmentioning

confidence: 99%

Survey of British and Irish orthoptists in the measurement of the AC/A ratio

Murray

Newsham

2014

British and Irish Orthoptic Journal

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Aims:To determine what practising orthoptists consider to be a normal AC/A ratio and on what evidence this is based. To assess which method of measurement is most commonly used and whether the ratio itself contributes to the diagnosis and management of strabismus in current practice. Methods: A prospective cross-sectional survey was designed and distributed to all orthoptists registered with the British and Irish Orthoptic Society (BIOS). The survey was web-based and consisted of 17 questions relating to the measurement of the accommodative convergence/accommodation (AC/A) ratio and its application to clinical practice. Prior to the survey being distributed nationally, a pilot survey was sent to a small group of practising orthoptists for validation.Results: There was a significant difference ( p < 0.05) in orthoptists' perception of the normal AC/A ratio (gradient and heterophoria) compared with published research. Ninety-three per cent stated that their definition of 'normal' was based on either clinical experience or what they were taught during training, with the gradient method at 33 cm being most commonly used (92.79%). The AC/A ratio is widely used (either 'always' or 'sometimes') in the diagnosis of convergence excess esotropia (CXS) (97.26%) and intermittent distance exotropia (IDEX) (93.75%) and (either 'always' or 'sometimes') in the management of CXS (88.89%) and IDEX (79.02%). Conclusion: The majority of orthoptists who participated are primarily measuring the stimulus AC/A ratio clinically. There is a discrepancy between participants' perception of a normal AC/A ratio and published research, yet the ratio is still used in the diagnosis and management of certain types of strabismus.

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Convergence Excess Esotropia: A Proposed New Classification and the Effect of Monocular Occlusion on the Ac/A Ratio

Cited by 10 publications

References 4 publications

Convergence excess accommodative esotropia: a descriptive review of patients presenting over a period of 10 years

Convergence excess accommodative esotropia: a descriptive review of patients presenting over a period of 10 years

Distance–near disparity esotropia: can we shrink the gap?

Survey of British and Irish orthoptists in the measurement of the AC/A ratio

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