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The effect of lid elevation on the cross-cover test
1Seton Hall University, Department of Neuroscience, Edison, New Jersey 08818, USA. mrosenberg@solarishs.org
Summary
Manual lid elevation during eye muscle balance testing can induce artificial phorias, potentially mimicking neurological conditions. Researchers recommend avoiding lid manipulation during phoria testing to ensure accurate results.
Area of Science:
- Ophthalmology
- Neuro-ophthalmology
Background:
- Accurate assessment of extraocular muscle balance is crucial for diagnosing and managing various visual disorders.
- The cross-cover test is a standard method for detecting phorias, which are latent deviations of the eyes.
Purpose of the Study:
- To investigate the impact of manual eyelid elevation on the results of the cross-cover test.
- To determine if manipulating the eyelid influences measurements of muscle balance.
Main Methods:
- A prospective study involving 100 orthophoric patients.
- The cross-cover test was repeated with manual elevation of the eyelid ipsilateral to the abducting eye.
- The presence and type of induced phoria were recorded.
Main Results:
- Eighty-four percent of patients and 76% of eyes developed a phoria when the eyelid was lifted.
- Vertical phorias (primarily ipsilateral hyperphoria) and horizontal phorias (esophoria) were frequently induced.
- Induced phorias were often symmetric.
Conclusions:
- Manual eyelid elevation can create an iatrogenic (artificially induced) phoria.
- This induced phoria may resemble a skew deviation or a fourth cranial nerve (IV nerve) paresis.
- Eyelid manipulation should be avoided during phoria testing to prevent inaccurate findings.
