Pregnancy causes widespread physiological effects throughout the body, including an increase in circulating blood volume (approximately 40–50%), dramatic hormonal changes (elevated estrogen, progesterone, and cortisol), and alterations in immune status. These changes directly and indirectly affect the eyes, leading to various ophthalmic events ranging from physiological changes to pathological changes that can threaten life or vision 1).
Ophthalmic changes associated with pregnancy can be broadly divided into reversible physiological changes and pathological changes requiring active intervention.
The main ophthalmic changes related to pregnancy are summarized below.
| Category | Main changes/diseases | Notes |
|---|---|---|
| Physiological changes | Decreased intraocular pressure (mean 2–3 mmHg) | Progesterone enhances aqueous humor outflow |
| Physiological changes | Corneal edema and curvature changes | May cause contact lens intolerance |
| Physiological changes | Temporary myopia and refractive changes | Often resolves postpartum |
| Physiological changes | Dry eye tendency | Tear film instability due to hormonal changes |
| Pathological changes | Pregnancy-induced hypertension (preeclampsia) | Affects about 3–5% of pregnant women2). Visual symptoms are a serious sign. |
| Pathological changes | Worsening of diabetic retinopathy (DR) | Worsens during pregnancy in about 10–30% of patients with pre-existing DR7) |
| Pathological changes | Central serous chorioretinopathy (CSC) | Common in the third trimester; elevated cortisol is involved12) |
The decrease in intraocular pressure during pregnancy is a favorable change for glaucoma management, but it also provides an opportunity to review the safety of current eye drops. Refractive surgery (LASIK, ICL, etc.) is contraindicated during pregnancy due to refractive instability and should be considered only after at least 6 months postpartum when refraction has stabilized3).
Yes. Hormonal changes can alter corneal shape, lens thickness, and intraocular pressure, causing temporary refractive changes (a tendency toward myopia). Corneal edema or curvature changes may also cause discomfort with contact lenses. These changes often resolve after delivery, but if a change in eyeglass prescription is made due to refractive changes during pregnancy, re-evaluation after delivery is necessary.
Ocular symptoms during pregnancy vary depending on the underlying disease.
Related to preeclampsia:
The above visual symptoms are signs of worsening preeclampsia and are risk indicators for eclampsia 6). Prompt consultation with an obstetrician and ophthalmologist is recommended.
During exacerbation of diabetic retinopathy:
CSC (central serous chorioretinopathy) related:
Symptoms due to physiological changes:
Preeclampsia
Retinal arteriolar changes: Arteriolar narrowing and silver-wire arterioles (evaluated based on the Keith-Wagener-Barker classification).
Hemorrhages and exudates: Flame-shaped hemorrhages and cotton-wool spots (soft exudates).
Elschnig spots: Yellow-white lesions due to choroidal infarction. A sign of poor prognosis.
Serous retinal detachment: Often bilateral. Choroidal ischemia → RPE damage → subretinal fluid accumulation.
Worsening of Diabetic Retinopathy
Increase in microaneurysms: Worsening of existing lesions or new appearance.
Macular edema: Serous or cystoid edema confirmed on OCT.
Neovascularization: Indicates progression from nonproliferative to proliferative DR.
Vitreous hemorrhage: Can cause sudden vision loss due to progression of proliferative DR.
CSC
Serous retinal detachment: Shallow serous retinal detachment localized to the macula.
OCT findings: Subretinal fluid accumulation is clearly visualized.
Fluorescein angiography: Performed only when necessary. Patterns include diffuse or pinpoint leakage.
Cortical Blindness (PRES)
Visual acuity: Transient complete to severe vision loss (bilateral).
Fundus findings: Often normal or only mildly abnormal.
Imaging: MRI/CT shows vasogenic edema in the occipital lobe (coordinate with neurology/obstetrics).
Course: Usually reversible with appropriate blood pressure control and MgSO₄ administration.
Flashes of light (photopsia) and blurred vision may be signs of worsening preeclampsia. Especially when accompanied by headache, swelling of the limbs, and elevated blood pressure, there is a risk of progression from preeclampsia to eclampsia (seizures). If these symptoms appear, it is important to immediately consult an obstetrician and also undergo an ophthalmological evaluation.
Preeclampsia is a condition characterized by persistent systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg after 20 weeks of gestation 4). The following mechanisms are important in the development of its ocular manifestations.
Risk factors for preeclampsia:
Pregnancy is an independent risk factor for progression of diabetic retinopathy (DR), and caution is especially needed in diabetic patients with pre-existing DR 7, 8).
The following mechanisms are involved in the worsening:
Risk factors for worsening of DR during pregnancy:
Elevated endogenous cortisol during pregnancy (especially in the third trimester) is thought to increase choroidal vascular permeability and induce CSC. Pregnancy-associated CSC often resolves spontaneously after delivery, but persistent cases can affect vision 12).
In ophthalmic evaluation during pregnancy, it is important to select examination methods that consider fetal safety.
| Examination method | Safety during pregnancy | Recommended scenarios |
|---|---|---|
| Dilated fundus examination (tropicamide/phenylephrine) | Safe (lacrimal sac compression recommended) | Can be performed in all cases. DR: every trimester |
| OCT (Optical Coherence Tomography) | Safe | Essential for evaluating serous retinal detachment and macular edema |
| Intraocular pressure measurement | Safe | Glaucoma follow-up |
| Fluorescein angiography (FA) | Generally avoided (FDA category C) | Only when absolutely necessary. Explain risks and benefits thoroughly |
| ICG angiography | Considered contraindicated | Avoid during pregnancy (transfers into breast milk) |
| Visual field test | Safe | Evaluation of cortical blindness and optic nerve diseases |
| Refraction test / corneal topography | Safe | Monitoring of refractive changes (decision to change correction) |
In pregnant women with diabetes and DR, fundus examination should be performed according to the following schedule:
Standard doses of mydriatic agents (tropicamide/phenylephrine eye drops) are considered safe for use during pregnancy when administered appropriately. However, it is recommended to minimize systemic absorption by gently pressing the lacrimal sac (inner corner of the eye) after instillation. For pregnant women with diabetic retinopathy, dilated fundus examination is essential to prevent vision loss, and the benefits far outweigh the risks.
The definitive treatment for preeclampsia is delivery (childbirth). Most ocular complications resolve spontaneously after delivery11).
Antihypertensive therapy: The following antihypertensive drugs can be safely used during pregnancy:
Contraindicated antihypertensives:
Management of ocular complications:
Pre-pregnancy preparation (planned pregnancy recommended):
Treatment strategy during pregnancy:
For patients using eye drops (e.g., for glaucoma) who become pregnant or are breastfeeding, safety evaluation of the medication is necessary. The safety classification of major glaucoma eye drops is shown below13, 14).
| Drug Class | Representative Drug | Assessment During Pregnancy | Assessment During Breastfeeding |
|---|---|---|---|
| Prostaglandin analogs | Latanoprost, bimatoprost | Contraindicated in principle (risk of uterine contractions) | Caution |
| Beta-blockers | Timolol, carteolol | Caution (risk of fetal bradycardia) | Caution |
| Alpha-2 agonists | Brimonidine | Caution (risk of central nervous system depression) | Contraindicated during breastfeeding (risk of neonatal respiratory depression) |
| Carbonic anhydrase inhibitors (eye drops) | Dorzolamide, brinzolamide | Caution (teratogenicity in animal studies) | Caution |
| Artificial tears / hyaluronic acid | Sodium hyaluronate eye drops | Safe | Safe |
| Tropicamide (mydriatic) | Mydrin P | Safe (lacrimal sac compression recommended) | Safe (lacrimal sac compression recommended) |
If continuing beta-blocker eye drops (e.g., timolol), thoroughly perform lacrimal sac compression (press the inner corner of the eye for 1–2 minutes immediately after instillation) to minimize systemic absorption. Brimonidine during breastfeeding carries a risk of central nervous system depression in the newborn and should generally not be used while nursing.
Safety varies greatly by medication. Prostaglandin analogs (e.g., latanoprost) may induce uterine contractions and are generally contraindicated during pregnancy. Beta-blockers (e.g., timolol) require caution for fetal bradycardia but may be continued with thorough lacrimal sac compression in some cases. Once pregnancy is confirmed, always consult your ophthalmologist and obstetrician to consider switching to a safe alternative. Neglecting glaucoma control can also lead to progression of visual field loss, so individualized assessment by a specialist is important.
Ocular involvement in preeclampsia arises from a complex mechanism based on systemic endothelial dysfunction5, 6).
Excessive production of the anti-angiogenic factor sFlt-1 (soluble Flt-1) from the placenta increases in the circulation, capturing and inactivating VEGF (vascular endothelial growth factor) and PlGF (placental growth factor). This results in systemic endothelial dysfunction, leading to hypertension, proteinuria, and edema.
In the eye, the following cascade occurs:
Cortical blindness due to PRES (posterior reversible encephalopathy syndrome) is a transient, reversible condition resulting from occipital hyperperfusion and blood-brain barrier disruption, and it resolves with appropriate blood pressure control and anticonvulsant therapy.
Worsening of diabetic retinopathy (DR) during pregnancy involves multiple interacting mechanisms. Increased insulin resistance amplifies blood glucose fluctuations, while increased circulating blood volume (approximately 40–50%) raises retinal blood flow, placing stress on existing microvascular lesions7, 8).
Elevations in growth hormone, prolactin, and IGF-1 promote angiogenesis and stimulate VEGF production. Additionally, in patients with poor glycemic control before pregnancy, rapid improvement of HbA1c in early pregnancy can cause a temporary worsening of retinopathy, known as the early worsening phenomenon. This is thought to result from disruption of local oxygen supply-demand balance in retinal ischemic areas due to rapid glycemic improvement8).
Elevated endogenous cortisol increases choroidal vascular permeability. Cortisol acts via mineralocorticoid receptors on choroidal endothelial cells, leading to choroidal hyperperfusion and increased vascular permeability → RPE dysfunction → serous retinal detachment12).
Progesterone relaxes the trabecular meshwork around Schlemm’s canal, reducing intraocular pressure by facilitating aqueous humor outflow. Additionally, hemodilution due to increased circulating blood volume during pregnancy decreases blood viscosity, and changes in episcleral venous pressure also contribute to intraocular pressure reduction. In patients with normal-tension glaucoma, the decrease in intraocular pressure during pregnancy may favorably stabilize symptoms 1).
Use of anti-VEGF drugs during pregnancy: Anti-VEGF drugs such as ranibizumab and aflibercept have shown teratogenicity in animal studies and are currently contraindicated during pregnancy. However, there are sporadic case reports of emergency use to prevent vision loss in pregnant women with proliferative diabetic retinopathy or intraocular neovascularization. Systematic data on safety are currently insufficient, and further evidence accumulation is needed 12).
Early prediction using choroidal thickness as a biomarker: Choroidal thickness measured by OCT fluctuates during pregnancy and has been reported to change prior to the onset of preeclampsia. Research is ongoing into the potential of choroidal thickness as an early ophthalmic biomarker for preeclampsia 10).
Correlation between sFlt-1/PlGF ratio and ocular pathology: The sFlt-1/PlGF ratio, which is becoming established as a predictive marker for preeclampsia, is being investigated for its potential correlation with the severity of fundus lesions. Observational studies have shown that cases with high ratios have a higher frequency of serous retinal detachment and Elschnig spots 5).
Standardization of glaucoma management protocols during pregnancy: Glaucoma treatment during pregnancy currently relies on individualized approaches, and there is a need for evidence-based systematic protocols. Selective laser trabeculoplasty (SLT) may be applicable during pregnancy as an alternative to pharmacotherapy, and further investigation is expected 13).
