Levator function revisited: a two-phase assessment of lid movement to better identify levator–superior rectus synkinesis
==========================================================================================================================

* Carole A Jones
* Edward J Lee
* John M Sparrow
* Richard A Harrad

## Abstract

**Aim** To assess a two-phase method of recording levator function in order to facilitate the identification of patients with ptosis who have a synkinesis between the levator and superior rectus muscles.

**Methods** 40 consecutive patients who attended oculoplastic clinics with ptosis and 22 patients with normal lid function were recruited. In each subject, levator function was recorded by the conventional method, measuring total upper eyelid excursion between the extremes of down-gaze and up-gaze. Levator function was also assessed using our novel two-phase approach in which upper-eyelid excursion is measured separately between down-gaze and primary position (Phase 1), and between primary position and up-gaze (Phase 2).

**Results** In normal patients and most of the patients with ptosis, the majority of lid movement and hence levator function occurs between down-gaze and the primary position (Phase1). In those patients with ptosis and levator–superior rectus synkinesis, a higher proportion of lid movement occurred on up-gaze (Phase2).

**Conclusion** The two-phase measurement of lid movement highlights levator function in differing gaze positions and facilitates the identification of those patients with levator–superior rectus synkinesis.

*   Assessment
*   eyelids
*   ptosis
*   synkinesis
*   diagnostic tests/investigation

## Introduction

In most instances of ptosis, the lid droop is evident on upgaze, and may be more obvious to the observer in this position. Harrad and Shuttleworth observed that in a subset of patients, the ptosis is seen to diminish progressively, or even disappear, as the eye moves above the primary position.1 These findings were explained as the result of synkinesis between the levator and superior rectus muscles on the basis of clinical observations and the results of forced duction tests.1 2

Harrad and Shuttleworth reported that failure to recognise synkinesis in ptosis patients can lead to corrective surgery being unsuccessful. In their initial description, seven patients were described, six of whom had presented to the authors over a 2-year period. It was suggested that the phenomenon may be common but often unrecognised, as assessing levator function in the conventional manner is insufficient to identify the subset of patients with synkinesis. They advised observing upper-lid position in nine directions of gaze in order to look for synkinesis.

In this paper, we propose a simple modification in the way levator function is assessed and evaluate its effectiveness in identifying synkinesis.

## Methods

Conventionally levator function is assessed by measuring total upper eyelid excursion between the extremes of down-gaze and up-gaze.3–8 This is usually performed with a ruler held in front of the patient's eye, and with the examiner pressing one digit over the patient's brow to prevent the action of the frontalis muscle contributing to the eyelid movement.

We propose a two-phase assessment of levator function, which is a simple modification of the conventional approach. The upper-eyelid excursion is measured in the same manner, with a ruler held in a fixed position against the patient's cheek, but the eyelid movement is recorded in two separate stages, namely:

1.  Phase 1: down-gaze to primary position;

2.  Phase 2: primary position to up-gaze.

This is illustrated in figure 1.

![Figure 1](http://bjo.bmj.com/https://bjo.bmj.com/content/bjophthalmol/94/2/229/F1.medium.gif)

[Figure 1](http://bjo.bmj.com/content/94/2/229/F1)

Figure 1 
Two-phase assessment of levator function. The upper-eyelid position is recorded in downgaze (C), primary position (B) and upgaze (A). The Phase 1 value is the lid movement between the down-gaze and primary position, and the Phase 2 value is the lid movement between the primary position and up-gaze.

In this study, we recorded both the conventional measurements and our two-phase approach in 40 consecutive patients with ptosis who attended specialist oculoplastic clinics in the Eye Ear and Mouth Unit, Maidstone Hospital and Bristol Eye Hospital, and, as a benchmarking exercise, in patients with no known eyelid abnormalities attending the general ophthalmology clinics. This latter group were examined in order to identify the normal distribution of eyelid movement into Phase 1 and Phase 2; as such, they were neither age- nor sex-matched to the ‘known-ptosis’ population. Patients with known myasthenia gravis were excluded from the study.

Sensitivity and specificity and the κ statistic were used to assess agreement between the existing standard method of testing for synkinesis,1 and a proposed new method based on the two phases of lid movement.

## Results

There was a predominance of females in both the normal and ptosis patient groups (64% and 65% respectively). The normal population were all adults (18 or more years old) except for one subject of 16 years old; all were attending the ophthalmology clinics because of non-eyelid-related complaints. The consecutive series of 40 ptosis patients was for the large part adults with aponeurotic ptosis (28 patients, mean age 69.5 years). The remaining ptosis patients consisted of six children and one adult with congenital ptosis, one child with double elevator palsy and jaw winking, one child and one adult with ptosis secondary to lid trauma, and two adults with ptosis following a III nerve palsy and a cerebrovascular accident respectively.

The summary of measurements taken at examination are shown in table 1. The normal population of patients were first examined using the conventional manner of assessing levator function (ie, measuring upper-eyelid excursion between down-gaze and up-gaze). The mean eyelid excursion in the normal population was 15.2 mm with a relatively small range of 14 to 18 mm. The same patients were then assessed using the two-phase measuring technique; this revealed that the majority of upper-lid movement (mean 10.1 mm corresponding to 66% of total excursion) occurred in Phase 1. Figure 2A shows the percentage of upper-eyelid excursion that occurred in Phase 1 and Phase 2 for each of the normal subjects; in all cases, 60% or more of the movement occurred in Phase 1.

View this table:
[Table 1](http://bjo.bmj.com/content/94/2/229/T1)

Table 1 
Summary of measurements

![Figure 2](http://bjo.bmj.com/https://bjo.bmj.com/content/bjophthalmol/94/2/229/F2.medium.gif)

[Figure 2](http://bjo.bmj.com/content/94/2/229/F2)

Figure 2 
Bar chart showing the percentage of total eye lid movement occurring in Phase 1 and Phase 2 for normals (A), and for patients with ptosis (B). The measurements for the six ptosis patients with a clinical diagnosis of synkinesis are shown to the right of (B) and highlighted with red markers.

The ‘known ptosis’ population were consecutive patients attending with ptosis of varying aetiology. All had a palpebral aperture of less than 9 mm in the primary position. As would be expected, the mean palpebral aperture and total lid movement, as measured with the conventional approach, were lower than in the normal population. This population also had a greater degree of variability as reflected by the standard deviations; this was also to be expected, as the ptosis population included both patients with aponeurotic dehiscence ptosis (who typically have conventional levator function measurements within the normal range) and patients with congenital ptosis in which levator function is reduced. Six of the patients with known ptosis were observed to have synkinesis on the basis of the known clinical characteristics,1 with ptosis in the primary position which became less evident in up-gaze (figure 3).

![Figure 3](http://bjo.bmj.com/https://bjo.bmj.com/content/bjophthalmol/94/2/229/F3.medium.gif)

[Figure 3](http://bjo.bmj.com/content/94/2/229/F3)

Figure 3 
Photographs of two patients with right ptosis. (A, B) Typical ptosis patient in primary position and upgaze respectively; the ptosis remains evident on upgaze. (C, D) Ptosis patient with superior rectus-levator synkinesis; the ptosis is marked in primary position (C) but is seen to diminish progressively in upgaze (D).

The results of the 2 Phase measurement of lid movement in the ptosis group were also more varied than those obtained in the normal population. As shown in figure 2B, in 35 patients the majority of the eyelid excursion occurred in Phase 1 (as was seen with the normal population) and in five of the 35 patients (four with disinsertion and one with Marcus Gunn jaw winking and double elevator palsy) 80% or more of the lid movement occurred in Phase 1. However, there was a distinct subgroup of five patients in whom the normal situation was reversed, with 50% or more of the movement occurring in Phase 2. In this subgroup, all patients were known to have ptosis with synkinesis, two patients had congenital ptosis, and the other three had ptosis following a brainstem cerebrovascular accident, lid trauma and a traumatic III nerve palsy respectively. The sixth patient with known synkinesis had a more normal pattern of lid movement, with 61% of the total lid movement occurring in Phase 1.

Agreement between the ‘standard method’ for identification of synkinesis and the presence of 50% or more of lid movement occurring in Phase 2 was assessed as a possible test to identify patients with synkinesis. In our sample of 40 ptosis patients, this test was 83% sensitive and 100% specific for synkinesis with κ equal to 0.89 (chance adjusted agreement) and exact agreement of 97.5%, thus representing excellent agreement.

## Discussion

The two-phase measurement of lid movement we have described is a simple modification of the standard means of assessing levator function. It takes less than 30 s to perform. Its use in a population with normal eyelid movements and a population with ptosis has demonstrated that in normal subjects and most patients with ptosis, of whatever cause, approximately two-thirds of the eyelid movement occurs between down-gaze and primary position (Phase 1). In five cases, a higher-than-expected Phase 1, of 80% or more of total eyelid movement, was recorded. This may be expected in cases of congenital ptosis, which is commonly noted to be worse in upgaze,9 but not in those with levator disinsertion, and this warrants further investigation. However, 50% or more of lid excursion occurring in Phase 2 (ie, between primary position and up-gaze) was 100% specific for synkinesis in our series. This method of assessing levator function can therefore be used to aid the detection of synkinesis. Sensitivity, however, was less than 100% (83%), as one of the patients with known synkinesis had a more normal pattern of lid movement.

The finding of synkinesis in six out of a series of 40 patients represents a prevalence of 15% (95% CI 6.9% to 29.6%). These results confirm that levator–superior rectus synkinesis is a relatively common condition, and it should be suspected in congenital ptosis and in those patients with a known neurological abnormality or trauma, as suggested by Harrad and Shuttleworth.1 Failure to identify synkinesis can adversely influence the success of lid surgery. The surgical algorithms available depend upon the total levator function, but we suggest that, as people rarely look above the primary position, it is more appropriate to base surgery on the functional levator excursion which corresponds to Phase 1 of our two-phase assessment. We have observed that taking account of total levator function leads to an under-correction of those patients with synkinesis, as the functional levator movement is overestimated by conventional assessments of lid excursion.

Furthermore, particular care should be taken in the intraoperative positioning of patients with synkinesis when undergoing surgery with local anaesthesia. Commonly, the use of a head rest can lead to a slight chin-down posture; if the patient is given a fixation target held directly above them, it may not be perpendicular to the plane of their face. In those patients with synkinesis, the ptosis can then be significantly underestimated and undercorrected as the lid is held higher than the primary position at which point the effect of the synkinesis comes into play.

## Conclusions

The two-phase assessment of levator function facilitates the identification of those patients with synkinesis. It is a simple modification of the conventional method of recording levator function, and we would recommend its use.

## Acknowledgments

This work has been presented in part at ARVO 2007 and ESOPRS 2007.

## Footnotes

*   Competing interests None.

*   Ethics approval Ethics approval was provided by the Cambridgeshire 4 Research Ethics Committee.

*   Patient consent Obtained.

*   Provenance and peer review Not commissioned; externally peer reviewed.

## References

1.  Harrad RA, Shuttleworth GN. Superior rectus–levator synkinesis: a previously unrecognized cause of failure of ptosis surgery. Ophthalmology 2000;107:1975–81.
    
    [CrossRef](http://bjo.bmj.com/lookup/external-ref?access_num=10.1016/S0161-6420(00)00170-6&link_type=DOI) 
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=11054316&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom) 

2.  Brodsky MC. The doctor's eye. Seeing through the myopathy of congenital ptosis. Ophthalmology 2000;107:1973–4.
    
    [CrossRef](http://bjo.bmj.com/lookup/external-ref?access_num=10.1016/S0161-6420(00)00286-4&link_type=DOI) 
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=11054315&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom) 

3.  Berke RN. A simplified Blaskovics operation for blepharoptosis. Results in ninety-one operations. AMA Arch Ophthalmol 1952;48:460–95.
    
    [CrossRef](http://bjo.bmj.com/lookup/external-ref?access_num=10.1001/archopht.1952.00920010469011&link_type=DOI) 
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=12975912&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom) 

4.  Johnson CC. Blepharoptosis: a general consideration of surgical methods with the results in 162 operations. Am J Ophthalmol 1954;38:129–62.
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=13180637&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom) 

5.  Nerad JA, Krachmer JH. Oculoplastic surgery: the requisites in ophthalmology. St Louis: Mosby Inc, 2001.
    
    

6.  Collin JRO. A manual of systemic eyelid surgery. 2nd rev edn. London, UK: Churchill Livingstone, 1989.
    
    

7.  Boboridis K, Assi A, Indar A, et al. Repeatability and reproducibility of upper eyelid measurements. Br J Ophthalmol 2001;85:99–101.
    
    [Abstract/FREE Full Text](http://bjo.bmj.com/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTI6ImJqb3BodGhhbG1vbCI7czo1OiJyZXNpZCI7czo3OiI4NS8xLzk5IjtzOjQ6ImF0b20iO3M6Mjc6Ii9iam9waHRoYWxtb2wvOTQvMi8yMjkuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

8.  Steel DHW, Harrad RA. Unilateral congenital ptosis with ipsilateral superior rectus muscle overaction. Am J Ophthalmol 1996;122:550–6.
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=8862053&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom) 

9.  Hirasawa C, Matsuo K, Kikuchi N, et al. Upgaze eyelid position allows differentiation between congenital and aponeurotic blepharoptosis according to the neurophysiology of eyelid retraction. Ann Plast Surg 2006;57:529–34.
    
    [CrossRef](http://bjo.bmj.com/lookup/external-ref?access_num=10.1097/01.sap.0000227484.76120.97&link_type=DOI) 
    
    [PubMed](http://bjo.bmj.com/lookup/external-ref?access_num=17060734&link_type=MED&atom=%2Fbjophthalmol%2F94%2F2%2F229.atom)