Preeclampsia is a pregnancy complication characterized by hypertension and proteinuria or organ dysfunction that develops after 20 weeks of gestation. Eclampsia refers to the condition where seizures are superimposed on preeclampsia. Hypertensive disorders of pregnancy complicate about 10% of all pregnancies and are a leading cause of perinatal and maternal mortality.
Ocular complications associated with preeclampsia are diverse. Hypertension-induced vasospasm, endothelial dysfunction, and hypercoagulability impair choroidal and retinal circulation, leading to characteristic fundus findings. Visual system involvement occurs in 30–100% of cases, and ophthalmic evaluation plays an important role in assessing the severity of preeclampsia.
HELLP syndrome is a severe form of preeclampsia characterized by the triad of hemolysis, elevated liver enzymes, and low platelets. Serous retinal detachment associated with HELLP syndrome occurs in about 0.9% of cases.
Visual disturbances occur in 30–100% of preeclampsia patients and are not rare. However, most resolve within a few weeks after blood pressure control and delivery. In severe cases, permanent visual impairment may remain if retinal pigment epithelium necrosis occurs. For details, see also “7. Latest Research and Future Prospects”.
Blurred vision (hazy vision) is the most frequent symptom.
Fundus findings reflect the degree of hypertension and severity of the condition.
Retinal Findings
Arteriolar spasm: Most common finding, observed in about 70%. Seen as irregular narrowing of vessel caliber.
Soft exudates: Cotton-wool spots due to retinal ischemia. Indicate nerve fiber layer infarction.
Flame-shaped hemorrhages/hard exudates: Occur as hypertensive changes. Leaked hard exudates may form a star-shaped pattern at the macula.
Papilledema: Swelling of the optic disc due to increased intracranial pressure or severe hypertension.
Choroidal/Retinal Pigment Epithelium Findings
Serous retinal detachment: Serous fluid accumulates under the retinal pigment epithelium and subretinal space due to damage to the choriocapillaris. Occurs in 1–2% of cases.
Elschnig spots: Retinal pigment epithelium degeneration over small infarcts of the choriocapillaris. Characteristic finding: a black spot surrounded by a pale yellow ring.
Siegrist streaks: Linear pigment deposits along choroidal arteries. Indicates chronic choroidal circulatory disturbance.
Retinal pigment epithelium mottling: Patchy pigmentary changes of the retinal pigment epithelium. Pigment epithelial changes after choroidal ischemia.
Serous RD is often bilateral and occurs inferiorly. Since differentiation from central serous chorioretinopathy (CSC) is necessary, refer to the section “4. Diagnosis and Examination Methods”.
Serous RD itself is not painful. However, headache and eye pain associated with preeclampsia may coexist. Subjective symptoms are mainly blurred vision and scotomas in the visual field.
The root cause of preeclampsia is thought to be inadequate invasion of the uterine spiral arteries by extravillous trophoblasts in the placenta. This leads to excessive secretion of soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) from the placenta, causing systemic endothelial dysfunction.
Endothelial dysfunction reduces nitric oxide (NO) production, leading to vasoconstriction, hypercoagulability, and increased vascular permeability. Locally in the eye, the choriocapillaris is particularly susceptible, and fibrinoid necrosis and capillary occlusion lead to serous RD.
The following risk factors are known:
The diagnosis of retinopathy associated with preeclampsia is based on a combination of fundus findings and clinical background. The presence of hypertension, proteinuria, and organ dysfunction during pregnancy is a prerequisite.
The characteristics of each examination method are shown below.
| Examination method | Main purpose |
|---|---|
| Fundus examination | Confirmation of arteriolar spasm, RD, and papilledema |
| OCT | Quantitative assessment of subretinal fluid, fibrin, and retinal pigment epithelium changes |
| Fluorescein angiography (FA) | Identification of delayed choroidal perfusion and retinal pigment epithelium damage |
| Fundus autofluorescence (FAF) | Evaluation of retinal pigment epithelium damage patterns |
It is important to differentiate from the following diseases.
| Differential Diagnosis | Key Differentiating Points |
|---|---|
| Central serous chorioretinopathy (CSC) | May worsen during pregnancy. Differentiate by FA findings. |
| Vogt-Koyanagi-Harada disease (VKH) | Bilateral serous RD and uveitis findings. |
| Disseminated intravascular coagulation (DIC) | Abnormal blood tests / HELLP syndrome |
| Malignant hypertensive retinopathy | Rapid blood pressure elevation, papilledema, cotton wool spots |
Fluorescein crosses the placenta, so careful judgment is required for fluorescein angiography during pregnancy. It should only be considered when clinically necessary and when other tests (e.g., OCT) cannot provide an alternative. Fundus autofluorescence (FAF) and OCT angiography (OCTA) are useful non-invasive alternatives.
In principle, active ophthalmologic intervention is not required for retinopathy associated with preeclampsia. Since retinal findings are secondary to the management of the underlying disease (preeclampsia/eclampsia), obstetric treatment takes priority.
Serous retinal detachment often improves rapidly after delivery. Retinal laser photocoagulation and vitrectomy are generally not indicated. In cases that persist after delivery, reconsider the differential diagnosis including central serous chorioretinopathy (CSC) and other diseases.
In severe preeclampsia and HELLP syndrome, rapid blood pressure fluctuations and coagulation disorders affect visual function. When vitreous hemorrhage or ischemic optic neuropathy is complicated, individual management is required.
The mechanism of ocular complications in preeclampsia is explained by the combination of systemic endothelial damage due to placenta-derived anti-angiogenic factors and the unique high blood flow and low autoregulation of the choroid.
The choriocapillaris is a high-flow vascular bed that supports the blood supply to the outer retina and has poor autoregulation. When endothelial injury from sFlt-1 and sEng is combined with acute systemic hypertension, the following changes occur in the choriocapillaris:
Following choriocapillaris injury, the pump function of the retinal pigment epithelium decreases. Leakage fluid from the choroid accumulates beneath the retinal pigment epithelium and subretinally, forming serous retinal detachment. In cases with fibrin deposition, recovery may be prolonged.
Excess of these two factors impairs endothelial function in both the retina and choroid, forming characteristic fundus findings.
Retinal arterioles undergo spasm and narrowing due to endothelial dysfunction and increased sympathetic activity. Chronic spasm leads to thickening and hardening of the vessel wall. In severe cases, retinal ischemia results in soft exudates and retinal hemorrhages.
The choriocapillaris has poorer autoregulation compared to retinal vessels and is more directly affected by rapid blood pressure elevation. Additionally, its high blood flow and large endothelial surface area make the effects of endothelial dysfunction more apparent. This is thought to explain why choroidal lesions such as Elschnig spots and serous retinal detachment are more prominent than retinal lesions in preeclampsia.
The usefulness of fundus findings in assessing the severity of preeclampsia is being studied. A correlation between the degree of arteriolar spasm and the severity of blood pressure and proteinuria has been suggested, and the application of quantitative retinal vessel diameter measurement for early risk stratification is being explored.
Non-invasive assessment of choriocapillaris perfusion using OCT angiography (OCTA) has been reported to be useful for early detection and monitoring of preeclampsia. It offers an excellent safety profile for examination during pregnancy as it can detect changes in choroidal blood flow without the use of fluorescein angiography.
Large-scale studies are needed to determine the frequency of long-term retinal pigment epithelium atrophy and visual dysfunction after severe preeclampsia. Permanent vision loss has been reported in cases with extensive Elschnig spots in the macula, and establishing a system for continuous postpartum ophthalmologic follow-up remains a challenge.
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