|Year : 1981 | Volume
| Issue : 4 | Page : 389-391
Department of Ophthalmology, S.P. Medical College, Bikaner, India
S P Mathur
Department of Ophthalmology, Medical College Jodhpur, Rajasthan
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mathur S P. Levator myometry. Indian J Ophthalmol 1981;29:389-91
Measurement of the strength of levator palpabrae superioris is of importance in management of ptosis and lid retraction.
An instrument named Levator Myometer has been devised for the purpose on the principles of Orbiculo-myometer. The levator muscle is made to contract against the resistance of a spring and measurement is recorded in terms of deflection of a beam of light by the moving mirror.
The instrument consists of an eye speculum. The upper limb is fixed to a small disc to rest under the upper border of the orbital margin. The lower limb is fixed to a lid clamp which can be screwed in position at the middle of the ciliary border of the upper eye lid. The joint of these limbs is fitted with a ball bearing. The upper limb of the speculum is attached with a stand. Both upper and lower limbs are provided with metal extensions between which there is spring which expands when the limbs of the speculum are brought closer. A mirror is provided at the joint which moves when the lower limb of the speculum is moved. A light source is provided at meter distance. The beam gets reflected from the mirror over a wall, which is caliberated in centimeters. [Figure - 1]
The patient's chin is placed in a head rest. The instrument alongwith the stand is placed towards the lid to be examined. The upper limb of the speculum rests under the upper orbital margin. The lower limb is clamped to the ciliary border of the upper lid. The light source is adjusted in a way that the mirror reflection is visible on the caliberations [Figure - 2].
The patient is asked to close the eyelids and then open fully. The deflection on the wall is noted. The process is repeated 6 times and the average reading is recorded.
In addition to this lid index is also examined. The upper lid measured from the upper orbital margin to the ciliary margin in natural position, and then after pulling the lid downwards by holding the cilia. The ratio of these two readings is calculated as lid index.
Size of the palpabral aperture is also measured for the sake of comparison.
Initially it was planned to find out the strength of levator palpabrae superioris in The average readings were as follows normal persons, at various age groups, both the sexes, and each eye, and compare this with lid index and size of palpabral aperture.
Subsequently similar studies were made on cases of ptosis, bilateral and unilateral, and in cases of lid retraction.
| Observations|| |
The study in normal persons was divided in 5 groups according to age. 20 cases were studied in each group out of which 10 were males and 10 females. Each eye was measured for palpabral aperture, lid index, and power of levator palpabrae superioris.
| Results|| |
From the above observations following results are evident :
- The strength of levator palpabrae superioris has been measured with some accuracy with our levator myometer.
- In normal persons the strength of levator palpabrae superioris reduced with the advancing age. There was no corresponding change in the size of the palpabral aperture or the lid index as per the age, sex, or the eye.
- The strength of levator palpabrae superioris was poorer in cases of congenital ptosis, and markedly increased in the cases of lid retraction due to thyrotoxicosis, as measured by our myometer.
A large study on the present lines is needed to arrive at better conclusions. It is hoped that the present method may be included as one of the diagnostic criteria and also to assess the results of treatment in diseases effecting levator palpabrae superioris.
[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2], [Table - 3]