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Case 41a
by
Professor Chua Chung Nen
The following patients complain that their
eyes appear different in size. However, the palpebral apertures are similar
in both eyes and the levator excursions are equal in both eyes.
Figure 1. A 17 year-old boy complain that
the right eye appears smaller than the left.
Figure 2. A 19 year-old woman complains her
right eye has always been smaller than the left.
Figure 3. A 27 year-old man seeks surgery
to make the two eyes equal in size.
Figure 4. A 18 year-old boy finds the left
eye always look less alert than the right eye.
a. What is the
diagnosis and how may this cause apparent asymmetry in eye size?
The apparent size differences in the two
eyes of these patients is the result of congenital skin crease
asymmetry. The eye that does not have the skin crease appears smaller
because the upper eyelid skin forms a hood over the lid margin (Figure 5
a and b).
 
Figure 5 a and b. A lateral view of the first patient shows hooding of
the skin over the right eyelid margin (a) which has no skin crease. The
eyelashes are pushed downwards by the skin causing lash ptosis. The skin
crease in the left eye acts as a barrier against skin hooding over the
eyelid margin (b).
The height of the skin crease is due to
the interplay of several structures1: the level of the
orbital septum, the amount of subcutaneous fat and the level of
insertion of the levator aponeurosis to the skin. In the East Asians
(mainly Chinese, Koreans and Japanese), the skin crease is lower or
absent in comparison with other races for the following anatomical
reasons (Figure 6):
a. the fusion of the orbital septum to the
levator aponeurosis is lower (usually below the superior tarsal border);
b. the presence of a thick subcutaneous
fat layer and preaponeurotic fat protrusion prevent the levator fibres
from inserting into the skin near the superior tarsal border;
c. the primary insertion of the levator
aponeurosis into the orbicularis muscle and the eyelid skin occurs
closer to the eyelid in the East Asians.
Figure 6. Picture showing the anatomical differences between the eyelids
of an East Asians (right)
and a
Caucasian (left). Blue arrows indicates the level of levator fibre
insertion into the eyelid
skin
and hence the skin crease2.
In addition, the insertions of the levator
fibres to the eyelid skin and the orbicularis oculi are weaker in East
Asians. Consequently, skin crease asymmetry is commoner in East Asians
than other races.
b. Suggest
ways of correcting the problem.
To achieve eyelid symmetry, the best way
is to create a symmetrical skin crease in the eye without one. This may
be achieved by two means:
a. Surgical method (Figure 7). The skin
crease may be created by excising a strip of skin +/- orbicularis oculi
or by the buried suture method.
b. Non-surgical method (Figure 8). The
skin crease may be formed using sticker or glue. This may be or by
other cosmetic means (sticker or glue).
Figure 7. The insertion of three buried
sutures allows the creation of a symmetric skin crease
in the left eye.
Figure 8. In patient who refuses surgery,
sticker may be used to create a skin crease.
Figure 8. Symmetrical skin creases
following sticker application in the right eye.
References:
1. The Asian upper eyelid: an anatomical study with comparison to the
Caucasian eyelid. Arch Ophthalmol.
1999 Jul;117(7):907-12. Jeong S, Lemke BN, Dortzbach RK, Park YG, Kang HK.
2. Strategies
for a successful corrective Asian blepharoplasty after previously failed
revisions.Plast Reconstr Surg.
2004 Oct;114(5):1270-7 Chen SH, Mardini S, Chen HC, Chen LM, Cheng MH, Chen
YR, Wei FC, Weng CJ.
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