CET// PHYSIOLOGY
1
CET
POINT
A number of physiological changes to the eye can occur during pregnancy. This
CET article provides further detail on the effects of pregnancy on pre-existing
ocular disease and the eye diseases that can arise during this time.
Ocular complications
during pregnancy
Mark Petrarca BSc (Hons), MCOptom
ABOUT THE
AUTHOR
46
Mark Petrarca
is an optometrist
currently
undertaking
medical and
surgical training at
St Bartholomew’s
Hospital and the
London School
of Medicine and
Dentistry.
INTRODUCTION
Pregnancy is both an exciting and
anxious time for expectant parents.
During pregnancy, widespread
physiological changes take place
in the female body due to the
hormones released from the
placenta and maternal endocrine
glands; these hormones have
effects on most organ systems,
including the eyes. In addition
to the physiological changes,
pregnancy can have an impact on
pre-existing ocular disease as well
as the development of new ocular
disease.1 This article will discuss
the most commonly reported ocular
complications during pregnancy.
PHYSIOLOGICAL CHANGES
TO THE EYE
During pregnancy there can be
significant physiological changes
to the structure and functioning of
the eye. Changes can occur in the
ocular adnexa and the cornea, with
potential effects on tear production
and intraocular pressure. These
Course code: C-39551 Deadline: March 7, 2015
LEARNING OBJECTIVES
To be able to explain to patients about the ocular changes that can
arise during pregnancy (Group 1.2.4)
To be able to recognise the ocular changes that can arise during
pregnancy by interpreting existing records (Group 2.2.5)
To understand the impact of pregnancy upon contact lens wear
(Group 5.2.1)
To understand the impact pregnancy may have on pre-existing ocular
pathology arising from systemic disease (Group 6.1.13)
LEARNING OBJECTIVES
To be able to explain to patients about the ocular changes that can
arise during pregnancy (Group 1.2.4)
To understand the impact of pregnancy upon contact lens wear
(Group 5.2.2)
To be aware of the ocular diseases that can arise during pregnancy
(Group 8.1.5)
LEARNING OBJECTIVES
To be able to explain to patients about the ocular changes that can
arise during pregnancy (Group 1.2.4)
To be able to recognise the ocular changes that can arise during
pregnancy by interpreting existing records (Group 2.2.5)
To understand the impact of pregnancy upon contact lens wear
(Group 5.4.1)
LEARNING OBJECTIVES
To understand the impact pregnancy may have on pre-existing ocular
pathology arising from systemic disease (Group 1.1.1)
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changes are typically benign,
temporary in nature, and will
resolve postpartum.
Ocular adnexal changes
The ocular adnexa can be affected
by a condition known as chloasma,
also called the ‘mask of pregnancy’
(see Figure 1). Chloasma refers to
the blotchy, brown discolouration
of the skin on the face around the
eyes. It is thought that elevated
levels of the hormones oestrogen
and progesterone stimulate
increased activity of melanocytes
in the skin. Spider angiomas, a type
of telangiectasia, can also develop
on the face and upper body.2 Both
of these skins conditions are
very common and will slowly fade
postpartum. Another frequently
reported change seen during and
after pregnancy is the onset of a
unilateral ptosis, and is the result
of increased fluid retention and
hormonal changes.3,4
Effect on tear production
Many women experience dry eyes
during pregnancy. Indeed, one study
reported reduced tear production
in 80% of pregnant women during
the third trimester.5 Disruption
of the lacrimal acinar cells is
thought to be the cause.6 Women
reporting symptoms of dry eyes
during pregnancy may, therefore,
benefit from use of lubricating eye
drops and other dry eye treatment
strategies.
Corneal changes and effect
on refraction
During pregnancy the cornea
can increase in curvature and
thickness.7,8 There may also be a
optometrytoday
decrease in corneal sensitivity.9
These corneal changes are the
result of increased water retention
by the ocular tissues and usually
occur later in pregnancy. As a
result, patients may present with
temporary alterations in refraction
and contact lens wearers are
more likely to report reduced lens
tolerance.10 It may, therefore, be
advisable to delay prescribing
new spectacle or contact lens
prescriptions until several weeks
postpartum. Refractive eye surgery
is also contraindicated until six
months after birth and following the
cessation of breast-feeding.
Effect on intraocular
pressure
Studies that measured intraocular
pressures in pregnant women,
found that during the second
half of pregnancy, intraocular
pressure (IOP) tends to decrease
in healthy eyes. In patients with
ocular hypertension, this decrease
can be even greater.11,12 Possible
mechanisms for these changes
include increased aqueous outflow,
decreased episcleral venous
pressure, and decreased scleral
rigidity. IOP changes typically return
to pre-pregnancy levels within two
months postpartum.13
THE EFFECTS OF
PREGNANCY ON PREEXISTING OCULAR DISEASE
Pregnancy can have a significant
impact on pre-existing eye
diseases. In some cases it can
cause further deterioration,
whereas in others it can be
beneficial. Eye diseases which can
be affected by pregnancy include:
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Figure 1
Chloasma seen as
brown blotches on
the face around the
eyes
diabetic retinopathy, glaucoma,
uveitis, ocular toxoplasmosis, optic
neuropathies, pituitary adenomas,
meningiomas, and migraines.
Diabetic retinopathy
This is the most common
ocular condition to be affected
by pregnancy. Studies have
demonstrated the link between
pregnancy and the progression
of diabetic retinopathy (DR).14
The ophthalmic status should
be carefully evaluated in these
patients with some suggesting
a review should be performed
every trimester and within three
months postpartum.15 Patients that
are diagnosed with gestational
diabetes pose a very low risk for the
development of retinopathy and,
therefore, do not require regular
retinopathy screening.16
Patients with severe nonproliferative and proliferative
retinopathy have the greatest
tendency for progression, while
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CET// PHYSIOLOGY
Ocular toxoplasmosis
Figure 2
Proliferative
diabetic
retinopathy
48
those with mild to no retinopathy
remain fairly stable during
pregnancy. In the Diabetes in Early
Pregnancy (DIEP) study, 55% of
women with moderate to severe
non-proliferative retinopathy
demonstrated disease progression
whereas 19% of women with mild
retinopathy and 10% with no
retinopathy showed progression.17
The progression of retinopathy
in pregnancy can depend on
a variety of factors including:
the severity of retinopathy at
conception, level of glycaemic
control, duration of diabetes,
and the presence of any other
coexisting vascular diseases.18
Laser photocoagulation is the
mainstay of treatment for DR. If
retinopathy progresses during
pregnancy and severe nonproliferative changes develop
it should be treated promptly.
Treatment should not be delayed
as proliferative changes frequently
progress despite intervention with
laser photocoagulation
(see Figure 2).18,19
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Glaucoma
Glaucoma is primarily a disease of
the older population, however, it can
affect women of childbearing age.
Studies have shown that pregnancy
affects the IOP of women with preexisting glaucoma. Both elevations
and reductions of IOP have been
reported during pregnancy. Visual
field test results may also fluctuate
during pregnancy.20 During labour,
there are reports of increased
instances of acute closed-angle
glaucoma.21
Uveitis
Chronic uveitis may improve during
pregnancy; this is possibly due
to immunosuppressive effects
and high steroid levels present in
pregnant women. When flare-ups
do occur, they tend to arise during
the first trimester; there is also
a rebound in activity within the
first six months postpartum. This
has been seen in patients with
ankylosing spondylitis, sarcoidosis
and Vogt Koyanagi-Harada
syndrome.22-24
Toxoplasmosis is a parasitic
disease caused by the protozoan
Toxoplasma gondii. It can be
acquired by ingestion of infected
meat or congenitally if the
mother becomes infected during
pregnancy and passes it on to the
developing foetus via transplacental
transmission. Following infection,
localised pigmented chorioretinal
scars are left behind which may
contain the organism in its inactive,
encysted form. Occasionally these
encysted Toxoplasma organisms
reactivate during pregnancy leading
to new episodes of toxoplasmosis.
Mild cases, which do not threaten
the macula, may resolve without
treatment. In more severe cases, the
duration of the inflammatory episode
can be reduced with a regime of
antimicrobials such as spiramycin,
pyrimethamine and sulfadiazine.
Corticosteroids may be given in
combination with antimicrobials
as an adjuvant therapy, however,
indications for their usage is
currently debated.25 Pregnant
women presenting with reactivated
toxoplasmic retinochoroiditis
are often concerned about the
possibility of transmitting congenital
toxoplasmosis to the foetus.
However, the risk of transmission
in these cases is very low. It is
thought that the foetus is protected
from congenital toxoplasmosis by
maternal antibodies that developed
after the mother’s initial infection.26,27
Optic neuropathies
There appears to be a reduced
incidence of optic neuritis during
pregnancy. This is probably due to
the immunosuppressive effects
associated with pregnancy. Optic
neuritis is often associated with
multiple sclerosis (MS). In patients
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with MS the relapse rate may
decrease in the third trimester
and then increase during the
early postpartum period.28 Optic
neuropathy has also been reported
in patients with hyperemesis
gravidarum – a complication
of pregnancy characterised by
intractable nausea, vomiting, and
dehydration and is estimated
to affect 0.5–2.0% of pregnant
women. Optic neuropathy occurs in
these cases due to excessive loss
or insufficient intake of vitamin B. 29
Pituitary adenomas
and meningiomas
In pregnancy, both pituitary
adenomas and meningiomas
tend to grow rapidly, and are
most likely to manifest during
the second half of pregnancy.
Intracranial disorders can present
with persistent headaches,
nausea and vomiting, decrease
in visual acuity, visual field loss,
and oculomotor palsies. Diagnosis
of intracranial disorders can be
delayed as some of the symptoms
associated with pregnancy, such as
nausea, vomiting and headaches
may be incorrectly attributed
to the pregnancy itself and not
as presentations of intracranial
disorders.30-32
Migraines
Migraine headaches are a
common occurrence, affecting
15% of the general population.33
There is a greater prevalence
of migraine headaches among
women, suggesting that hormone
levels, especially oestrogen,
can influence the occurrence,
frequency, and severity of migraine
attacks. Oestrogen levels fluctuate
during pregnancy and this can
potentially lead to changes in the
characteristics of migraine attacks.
Both increased and decreased
frequencies have been reported.34
EYE DISEASE ASSOCIATED
WITH PREGNANCY
Pregnancies that are abnormal
can lead to the development
of eye disease. Examples of
pregnancy-associated diseases
with ocular manifestations include:
pre-eclampsia/eclampsia and
vascular clotting disorders such
as disseminated intravascular
coagulation (DIC), thrombotic
thrombocytopenic purpura (TTP),
and haemolysis, elevated liver
enzymes, and low platelets (HELLP)
syndrome.
Pre-eclampsia and
eclampsia
Pre-eclampsia is a condition
characterised by hypertension
and proteinuria during pregnancy.
It affects about 5% of women
and occurs in the second half of
pregnancy.35 If a pregnant woman
with pre-eclampsia develops
seizures, then the disorder is
classified as eclampsia.36 Visual
disturbances, including scotoma,
reduced vision and photopsia,
are reported in 25% of women
with severe pre-eclampsia and in
50% of women with eclampsia.37
On examination the three most
common ocular findings are
hypertensive retinopathy, serous
retinal detachment, and cortical
blindness.
In pregnancy-induced
hypertensive retinopathy, 60% of
women will develop retinal arteriolar
spasm and narrowing. Other
findings may include haemorrhages,
hard exudates, cotton wool spots,
and papilloedema.38 The degree of
retinopathy usually correlates with
the severity of pre-eclampsia.39
The incidence of serous retinal
detachments is approximately
1% for severe pre-eclampsia and
10% for eclamptic patients.40 It is
thought to be caused by choroidal
ischaemia.41
Cortical blindness has also been
reported as a cause of visual loss
in women with pre-eclampsia and
eclampsia. Cortical blindness
affects approximately 1–15% of
patients with severe pre-eclampsia
and eclampsia. It can cause sudden
bilateral visual loss in the presence
of normal fundi and normal pupillary
responses.42 Cerebral oedema in the
occipital cortex is believed to be the
cause of vision loss. One proposed
theory suggests that vasospasms
associated with pre-eclampsia
cause transient ischaemia, which
in turn produces cytotoxic oedema.
Vision usually returns within four
hours to eight days.43,44
HELLP syndrome
Approximately 4–12% of women with
severe pre-eclampsia or eclampsia
develop haemolysis, elevated
liver enzymes, and low platelets
(HELLP) syndrome. HELLP can be
fatal to both mother and unborn
baby. It usually occurs in the last
trimester of pregnancy. However,
approximately one-third of HELLP
cases occur after the baby is born in
the first week after delivery.45 Ocular
findings associated with HELLP
syndrome include bilateral serous
retinal detachment with yellow/
white sub-retinal opacities and
sometimes vitreous haemorrhage.46
‘‘’’
Pregnancy-associated diseases
with ocular manifestations include
pre-eclampsia/eclampsia and
vascular clotting disorders
Central serous retinopathy
In central serous retinopathy
(CSR) there is an accumulation of
sub-retinal fluid and detachment
of the neurosensory retina (see
Figure 3, page 50). CSR is a
disease that is usually associated
with men between 20–50 years
of age. However, in pregnancy
the incidence of CSR in women
increases significantly. Patients
typically present with unilateral
metamorphopsia, reduced visual
acuity, a positive scotoma and
micropsia. The onset of visual
symptoms usually occurs during
the third trimester but it can also
develop during the first and second
trimesters.47 Elevated levels of
endogenous cortisol are thought
to lead to increased permeability
in the blood-retinal barrier,
choriocapillaris, and retinal pigment
epithelium (RPE). White fibrous
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49
CET// PHYSIOLOGY
eye for DIC to manifest. Patients
often complain of visual loss from
choroidal infarction or haemorrhage,
or serous retinal detachments.51
TTP is a rare systemic coagulopathy
that is similar to DIC, characterised
by thrombus formation in small
vessels and platelet deficiencies.
Clinical findings are generally related
to retinal arteriole narrowing, serous
retinal detachments and optic
disc oedema.51,52
USAGE OF OPHTHALMIC
DRUGS IN PREGNANCY
50
Figure 3
OCT showing
central serous
retinopathy. Image
courtesy of BBR
Optometry Ltd,
Hereford
subretinal exudates are seen in 90%
of pregnancy-associated cases of
CSR, compared with 20% of general
cases.48 Diagnosis is typically made
clinically, but optical coherence
tomography has shown to be useful
in both identifying and monitoring
patients with CSR.49 Observation
is the treatment of choice as the
condition usually resolves within
a few months of postpartum.
However, changes to the central
visual field, metamorphopsia, and
RPE alterations may persist.
Occlusive vascular disorders
Pregnancy is associated with
changes in the coagulation and
fibrinolytic systems. As a result, the
ease at which blood coagulates and
forms clots is increased. Pregnancy
is, therefore, a hypercoagulative
state; this phenomenon is believed
to be a physiological adaptive
mechanism to prevent excessive
haemorrhaging during pregnancy
and child birth.50 Unfortunately,
this hypercoagulative state is
associated with an increased risk
of developing vessel occlusions
and clotting disorders such
as disseminated intravascular
coagulation (DIC) and thrombotic
thrombocytopenic purpura (TTP).
Both branch and central retinal
artery occlusions can occur in
pregnancy. Retinal vein occlusions
can also occur but are rare. DIC
is an acute pathological process
associated with widespread
activation of the clotting system
resulting in thrombus formation
in small vessels throughout the
body. This leads to compromised
tissue blood flow and ultimately
leads to multiple organ damage.
Additionally, the coagulation
process consumes large quantities
of clotting factors and platelets,
and as a result, normal clotting
is disrupted and severe bleeding
occurs. It is associated with
obstetric complications such as
abruptio placentae, pre-eclampsia/
eclampsia, amniotic fluid embolism,
retained intrauterine fetal demise,
and septic abortion. The choroid is
the most common location in the
Exam questions
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The usage of ophthalmic
medications during pregnancy
can pose a potential risk to both the
mother and foetus. In the majority
of cases the risk is usually low, due
to the dosages used and the topical
mode of administration.53 The risk
of systemic absorption can be further
reduced by punctal occlusion, eyelid
closure, and blotting the excess
drops away during administration.54
Pregnant women that require regular
use of ophthalmic medications
for chronic eye diseases, such as
glaucoma for example, may need to
have their medications changed or
consider alternative treatments for
the duration of their pregnancy.
CONCLUSION
Practitioners will examine the
eyes of many pregnant women in
routine practice. In the vast majority
of cases the ocular changes seen in
pregnancy are either physiological
or transient in nature. Occasionally,
pregnancy can be associated with
pathology that can cause sight
loss. It is, therefore, important that
clinicians have a firm understanding
of the various ocular changes
associated with pregnancy and
the implications they may have
for management.
References
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