Observations on Bell's phenomenon after levator surgery

SM Betharia; BR Kalra

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Year : 1985 | Volume : 33 | Issue : 2 | Page : 109-111

Observations on Bell's phenomenon after levator surgery

SM Betharia, BR Kalra
Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
S M Betharia
Dr. Rajendra Prasad Centre for Ophthaimic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 29
India

Source of Support: None, Conflict of Interest: None

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PMID: 3833733

How to cite this article:
Betharia S M, Kalra B R. Observations on Bell's phenomenon after levator surgery. Indian J Ophthalmol 1985;33:109-11

How to cite this URL:
Betharia S M, Kalra B R. Observations on Bell's phenomenon after levator surgery. Indian J Ophthalmol [serial online] 1985 [cited 2021 Mar 2];33:109-11. Available from: https://www.ijo.in/text.asp?1985/33/2/109/30832

Bell's phenomenon is an important protective reflex wherein the globe is turned upwards and slightly outwards during the eye closure[1]. Its preoperative assessment is a must in every case of ptosis surgery. The aim of the levator surgery is not only to lift the lid symmetrically but also to give minimum lagophthalmos to avoid exposure keratitis postoperatively. The purpose of this paper is to highlight a few important observations on Bell's phenomenon following levator surgery which has an important bearing on the success of the operation.

Case report

Case No. 1-H. K., 22 years male was having residual ptosis R. E. 3 mm with 4 mm of L. P. S. action with good Bell's Phenomenon and normal corneal sensations. L. P. S. resection of 14 mm was done. Postoperatively the superior rectus underaction and poor Bell's phenomenon with minimum lagophthalmos, was noted. He developed exposure keratitis and central tarsorrhaphy was done as the Bell's phenomenon remained poor even after 12 days.

Case No. 2-R. J., 24 years female was a case of progressive external ophthalmoplegia.

L. P. S. action was 6 mm and ptosis was 4mm in both eyes. Bell's phenomenon was normal. Bilateral L. P. S. resection of 12 mm was done and the histopathological report of the resected levator was found to be compatible with muscular dystrophy. Cosmetic result postoperatively was good with minimum lagophthalmos but Bell's phenomenon was found to be totally absent and consequently the patient developed severe exposure keratitis which recovered on giving a trial of soft lenses and paramedian tarsorrhaphy was done in both eyes.

Case No. 3-S. V., 11 years male child was diagnosed as a congenital complicated partial ptosis with epicanthus and antimongoloid slant of palpebral fissures [Figure l]a. The ptosis was 4 mm in R. E. with 4 mm of L. P. S. action. The Bell's phenomenon was good and corneal sensations were normal. L. P. S. resection of 20 mm was done in R. E. The cosmetic result was good in the postoperative period [Figure - 1]b but the Bell's phenomenon was surprisingly found to be inversed. On closure of the eye ball moved down and in [Figure - 1]C instead of normal upward and outward direction. The Frost Suture was kept for 7 days. The Bell's phenomenon was restored after 12 days when the patient came for suture removal during subsequent follow up.

Discussion

The levator surgery for ptosis is the most physiological and gives rise to a minimal lagophthalmos. Even on moderate L. P. S resection we have observed development of serious postoperative complication in the form of exposure keratitis (case I and 2) though the cosmetic appearance was good and lagophthalmos was minimum. This was basically due to gross reduction in the Bell's phenomenon seen during immediate postoperative period.

In case no. 3 we have to our surprise noted an inverse Bell's phenomenon where the eye ball on forcible closure went down and in direction.

This reduction in Bell's phenomenon during early postoperative period is seen in residual ptosis, ptosis with myopathy and also in congenital complicated ptosis. After these 3 cases serving as eye opener we have now started observing Bell's phenomenon carefully during postoperative period and found that cases of residual ptosis undergoing repeat surgery are more prone for this reduction in Bell's phenomenon.

The serious complication of exposure keratitis developed due to poor Bell's phenomenon postoperatively required soft lens therapy along with central or paramedian tarsorrhaphy as in case no. 1 and 2 and once the corneal condition improved and Bell's phenomenon recovered reasonably, the tarsorrhaphy was removed after 2 months in case no. 1. In case no. 3 we have successfully prevented this complication by judiciously keeping the inverted Frost suture pulled up thereby giving complete protection to the cornea although the Bell's phenomenon was inversed. In this patient it took 12 days for recovery and normal restoration of Bell's phenomenon.

We feel that recording of Bell's phenomenon should be a quantitative assessment wherein only light closure of palpebral aperture should be done after elevating the ptosed lid to the desirable level and noting the excursion of the eye ball by measuring the lower limbal distance from the centre of the lower lid margin. Many a times a forcible closure gives a false impression that the given case is having a good Bell's phenomenon but after the operation when the patient is sleeping he cannot exercise a forcible closure and thereby the cornea remains exposed leading to exposure keratitis.

Summary

Serious complication of exposure keratitis following levator surgery due to gross reduction in Bell's phenomenon are highlighted. Methods to prevent such complication by careful preoperative and postoperative assessment of Bell's phenomenon are stressed.

References