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Ahmad M. Mansour, MD �
Department of Ophthalmology
American University of Beirut
Montefiore Medical Center
Albert Einstein College of Medicine
New York, USA
Paul Henkind (deceased)
Post-operative myopic shift due to trapped
We describe a rare post-operative complication caused
by Healon trapped within the capsular bag behind a
posterior chamber intraocular lens. This resulted in a
shallowed anterior chamber and a myopic shift, both of
which were corrected by removal of the trapped Healon.
A 76-year-old woman complaining of blurred vision in
her left eye was diagnosed as having a cortical cataract.
Her visual acuities were 6/12 right and 6/18 left.
Anterior and posterior segment examination was
otherwise unremarkable and in particular she had
normal anterior chamber depths (right 2.47 mm, left 2.55
mm). The patient agreed to a left cataract extraction with
intraocular lens implantation. Her pre-operative
refraction was +3.75/ -2.50 in her right eye and
+ 1.50/ -1.75 in her left eye. The aim was to make the left
eye emmetropic and the posterior chamber lens needed
to achieve this was a 23 dioptre lens. An uneventful left
phacoemulsification using a foldable intraocular implant
(8590B Chiron) inserted under sodium hyaluronate 5000
(Healon) was carried out after a continuous circular
capsulorhexis. The Healon was aspirated from in front of
the implant at the end of the operation.
Post-operatively she had a visual acuity of 6/6 and a
refraction of -1.75/ -1.75. A shallow anterior chamber
was noted. A greater than normal distance between the
posterior surface of the intraocular lens and the surface
of the posterior capsule was also noted. The shallow
anterior chamber, distended capsular bag and refraction
remained unchanged over the following 2 months. It was
decided that the Healon needed removing from the
capsular bag and that this should be done surgically as
the capsulorhexis edge was obscured by the pupil
margin (even when the pupil was dilated). The Healon
was aspirated after inserting a cannula into the capsular
bag between the edge of the intraocular lens optic and
the capsulorhexis margin. The procedure was
Post-operatively the patient's vision remained at 6/6,
but the anterior chamber deepened, the capsular bag
distension disappeared and her refraction improved to
-0.25/ -0.50. At no stage was there excessive intraocular
inflammation or raised intraocular pressure and the
Healon remained clear throughout this
2 month period.
Hyaluronic acid is a naturally occurring
glycosaminoglycan which, due to its viscosity, elasticity
and other properties, acts as an ocular lubricant and an
anterior chamber depth maintainer. Formulations of
exogenous hyaluronic acid for clinical use are derived
from the dermis of rooster combs or by fermentation in
streptococcal cultures. The physical properties of
hyaluronic acid and its use in ophthalmic surgery have
been described in several detailed reviews.l-4 The high
viscosity when stationary permits maintenance of depth
and shape of the anterior chamber and manipulation of
tissues, and the low viscosity when forced through a
cannula facilitates removal and injection. It reduces the
damage to the corneal endothelium during intraocular
It has been shown in animal experiments that the half
life of exogenous hyaluronic acid in the anterior chamber
of the eye is directly related to the injected volume.5 It is
uncertain how this is related to molecular weight.6,7
Local catabolisation of hyaluronic acid after its injection
into the anterior chamber is negligible. Data in rabbits
indicate that it is degraded mainly in the liver after
diffusion from the eye into the plasma. In our case the
Healon was obviously trapped behind the intraocular
implant and excretion was occurring extremely slowly, if
at all, therefore requiring its removal. Shammas8 and
Holtz9 have also described similar patients with post
operative myopia, shallow anterior chambers and
distended posterior capsular bag due to trapped Healon.
They chose to release the trapped Healon by creating a
hole in the anterior capsule with Nd:YAG laser. This
resolved the capsular bag distension, deepened the
anterior chamber and corrected the myopic shift. Due to
a large capsulorhexis this was not possible in our case as
the pupil margin obscured the edge of the capsule even
in the dilated state.
We report this case to emphasise the importance of
careful and thorough removal of Healon from behind the
posterior chamber lens intraoperatively and also to
highlight that an unexpected myopic refraction
postoperatively may be due to Healon trapped within
the capsular bag behind the implant.
1. Goa KL, Benfield P. Hyaluronic acid: a review of its
pharmacology and use as a surgical aid in ophthalmology,
and its therapeutic potential in joint disease and wound
healing. Drugs 1994;47:3536--6 6.
2. Arshinoff S. The physical properties of ophthalmic
viscoelastics in cataract surgery. Proceedings of the National
Ophthalmic Speakers Program (NOSP), Montreal. Medicopea
3. Bothner H, Wik O. Rheology of intraocular solutions. In:
Rosen ES, editor. Viscoelastic materials: basic science and
clinical applications. Vision and visual health care. Pergamon
4. Eisner G. Use of viscoelastic tools in ophthalmic surgery. In:
Eisner G, editor. Ophthalmic viscosurgery. Medicopea
5. Laurant UBG, Fraser JRE. Disappearance of concentrated
hyaluron from the anterior chamber in monkey eyes. Exp Eye
6. Miyauchi S, Iwata S. Evaluations on the usefulness of viscous
agents in anterior surgery. J Ocular Pharmacol 1989;5:221-32.
7. Laurant UBG, Fraser JRE. Turnover of hyaluronate in the
aqueous humor and vitreous body of the rabbit. Exp Eye Res
8. Shammas HJ. Relaxing the fibrosis capsulorhexis rim to
correct induced hyperopia after phacoemulsification. J
Cataract Refract Surg 1995;21:228-9.
9. Holtz SJ. Postoperative capsular bag distension. J Cataract
Refract Surg 1992;18:310-7.
Anne C. Reck �
Moorfields Eye Hospital
London EC1V 2PD, UK
The Toronto Hospital
Queen Alexandra Hospital