Pregnancy is a physiological situation in which there are variations in the functioning of organs and systems, which are affected to a greater or lesser degree. The maternal endocrine system and the placenta, together with other changes, cause ocular anomalies that are reversible and rarely leave sequelae or are permanent.

The physiological, haematological, hormonal, immunological, metabolic changes in the body of a pregnant woman deserve special consideration, as does the vision.

In this way we can separate 3 types of ocular disturbances or effects during the pregnancy monitoring:

1. Physiological changes that occur during pregnancy:

Corneal changes

Physiological changes affecting the cornea are likely to be due to water retention and include a decrease in corneal sensitivity and an increase in both corneal thickness and corneal curvature.

These changes occur later in pregnancy and can lead to temporary refractive disturbances, making pregnancy a contraindication for refractive eye surgery.

In addition, intolerance to contact lenses occurs, so it is advisable to delay fitting and prescribe new corrective lenses or contact lenses until several weeks after delivery.

Dry eye

Due to a disruption of production in the lacrimal cells.

Intraocular pressure variations

The decrease in intraocular pressure occurs particularly in the second half of pregnancy. In patients with ocular hypertension or glaucoma, this decrease may be even greater. Intraocular pressure changes usually return to pre-pregnancy levels within two months postpartum.

Chloasma

It is an increased pigmentation around the eyes and cheeks, which is common during pregnancy. In addition, benign angiomas can be seen in the form of "spider veins" that commonly develop on the face and upper body. Both of these changes often resolve postpartum.

2. Vision disorders that can occur during pregnancy

Pre-eclampsia and eclampsia

Visual symptoms tend to worsen with increasing disease severity and include blurred or decreased vision, photophobia, scotomas, diplopia, visual field defects and blindness.

Other ocular abnormalities seen in pre-eclampsia and eclampsia include retinal haemorrhages, papillophlebitis, macular oedema, retinal pigment epithelial lesions, retinal vein and retinal artery occlusion, optic neuritis, optic atrophy and ischaemic optic neuropathy.

Retinal detachment occurs in less than 1 % of patients with pre-eclampsia and in 10 percent with eclampsia. It tends to be bilateral, diagnosed after delivery, more common in primiparous women and more common in women undergoing caesarean section; it tends to resolve completely after delivery.

3. Vision disorders already present but modified in pregnancy

Diabetic retinopathy

Studies have shown that CVapregnancy is an independent risk factor for worsening diabetic retinopathy. Postpartum regression may occur at an uncertain rate and time.

The standard treatment for diabetic retinopathy is laser photocoagulation surgery.

There is also a worsening of macular oedema that often recedes after delivery, but may persist and lead to long-term visual loss.

Uveitis

For chronic non-infectious uveitis, pregnancy seems to confer a beneficial effect, with a lower incidence of flare-ups and when they occur they are more frequent during the first trimester.

Toxoplasmosis

Latent ocular toxoplasmosis can reactivate during pregnancy, and although there is a negligible risk to the foetus of acquiring congenital toxoplasmosis, special treatment is required.