Symmetrical Versus Asymmetrical Inferior Oblique Muscle Weakening Surgery for Asymmetrical Inferior Oblique Overaction
试验速览
- 阶段
- 不适用
- 入组人数
- 28
- 试验地点
- 1
- 主要终点
- Normalization of IO action
研究概览
简要总结
Overaction of the inferior oblique (IO) muscle is a commonly observed component of childhood strabismus, and is often seen combined with other ocular deviations. It manifests with excessive elevation of the affected eye in adduction, and may cause a pattern strabismus and vertical deviation of the affected eye. IO overaction (IOOA) may be primary or secondary to superior oblique underaction, is often bilateral, and may be symmetrical or asymmetrical.
Surgical management of the overacting IO muscle is often required to achieve ocular alignment. The most commonly performed IO muscle weakening procedures are IO myectomy and graded IO recession. The surgical decision is primarily based on degree of overaction of the IO muscle. Various studies have compared the two IO weakening procedures and have reported a similar success rate for both procedures.
The aim of this study is to compare the effect of two IO weakening procedures (symmetrical vs asymmetrical myectomy or graded recession) in normalizing the IOOA, obtaining vertical alignment and collapse of pattern, when employed in the treatment of asymmetrical IOOA.
详细描述
- Background (Introduction):
An excessive elevation of the eyeball on adduction, both on horizontal movement and in upgaze, is often due to inferior oblique over action (IOOA). It is a common disorder of ocular motility, and is usually bilateral and asymmetrical. The asymmetry may be due to difference in time of onset or difference in degree of severity of the IO overaction in the two eyes.
IOOA may be primary and of unknown etiology, or secondary to a congenital superior oblique palsy. Primary IOOA is commonly associated with congenital esotropia, with the oblique overaction usually presenting after one year of age. In addition to congenital esotropia, primary IO overaction may be associated with exotropia or may occur as an isolated IO overaction without other strabismus.
IOOA can be isolated or combined with other types of deviations. Primary IOOA has been reported to develop between one to six years of age in up to two-thirds of patients with infantile esotropia, and is usually bilateral. The cause is unknown. IOOA may be seen in 70% of patients with esotropia and in 30% of patients with exotropia. Secondary IOOA is often unilateral and is caused by paresis or paralysis of the superior oblique muscle.
Depending on severity, IOOA is graded as: (+1) to (+4) overaction. A (+1) overaction indicates slight over elevation in adduction, and (+4) overaction indicates severe over elevation in adduction. It has been suggested that (+1), (+2), (+3) and (+4) overactions roughly translate to 5, 10, 15 and 20 prism diopter (PD) of hypertropia on side gaze.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Participant, Outcomes Assessor)
盲法说明
Both participants and outcome assessor (the orthoptist) will be blinded regarding the type of surgery
入排标准
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Comitant esotropia or exotropia with bilateral, asymmetrical IOOA
- •Vertical deviation in primary position < 15 PD
- •Minimum of 3 months follow up
排除标准
- •Paralytic or Restrictive Strabismus
- •Dissociated vertical deviation
- •History of previous IO surgery
结局指标
主要结局
Normalization of IO action
时间窗: 3 months
To compare effect of symmetrical vs asymmetrical IO weakening in reducing IOOA (scale of +1 to +4)
次要结局
- Vertical ocular alignment(3 months)
- Collapse of "V" pattern(3 months)
研究者
Anuradha Ganesh
Senior Consultant
Sultan Qaboos University