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Editor,—Pre-eclampsia is characterised by hypertension, proteinuria, and generalised body oedema, which occurs during the third trimester of pregnancy. Ophthalmological changes related to pre-eclampsia include involvement of retinal or choroidal vasculature, with the presence of cotton wool spots, haemorrhages and serous retinal detachment.1 The antiphospholipid syndrome is characterised by the triad of arterial or venous thrombosis, recurrent abortions, and thrombocytopenia.
Choroidal neovascular membrane (CNV) is a complication which occurs in many ocular diseases including age related macular degeneration, myopic degeneration, and presumed ocular histoplasmosis syndrome (POHS). It occurs as a degenerative process (type I) or secondary to damage in the choriocapillaris-Bruch's membrane-retinal pigmented epithelium (RPE) complex (type II).
We report a case of choroidal neovascular membrane as a complication of pre-eclampsia and the antiphospholipid syndrome.
A 35 year old woman was referred for ophthalmological examination with distortion of vision in her left eye. She noticed this in her left eye vision 2 weeks before an episode of pre-eclampsia which led to a stillbirth at 26 weeks of pregnancy. One week before her ophthalmic presentation she was diagnosed as having the antiphospholipid syndrome, and treated with aspirin 75 mg a day.
She had corrected visual acuity of 6/5 in both eyes, with normal anterior segments and intraocular pressure of 20 mm Hg in the right eye and 22 mm Hg in the left. She had no changes in the right fundus and the left fundus revealed a subretinal lesion surrounded by fluid (Fig 1). The clinical appearance of the lesion was consistent with the diagnosis of choroidal neovascular membrane (CNV) which was confirmed by fluorescein angiography (Fig 2). The patient had good vision and no symptoms, therefore treatment was considered unnecessary.
One month later she returned and her left visual acuity had deteriorated to 6/6 and she also complained of distortion and diplopia. The decision to proceed with laser photocoagulation was made as the CNV had enlarged both clinically and on fluorescein angiography.
One month after treatment she was maintaining visual acuity of 6/5 on the right eye and 6/6 in the left eye. Her fundus examination disclose resolution of the subretinal membrane with a well demarcated scar in the left eye.
Ocular changes in pre-eclampsia are well known although they are unusual.1 When they occur they are usually secondary to high blood pressure levels. The pathogenesis of the serous retinal detachment is not well understood. Hayreh et al suggested that serous retinal detachment in pre-eclampsia was caused by choroidal ischaemia secondary to accelerated hypertension.2 The incidence of serous retinal detachment is approximately 1% for severe pre-eclampsia and 10% for eclamptic patients.3
Lesions in the RPE and outer retina have also been described. Saito and Tano4 demonstrated 47 eyes with RPE changes, which were mainly located in the macular region. These lesions corresponded to areas of delayed choroidal filling seen by fluorescein angiography. Some authors suggested that the macular region is more vulnerable to ischaemic disorders.
Changes in the blood viscosity, increased levels of vasoactive hormones, significant increases in blood volume and cardiac output may lead to damage of choriocapillaris and RPE. Rhee et al reported three cases in which CNV was diagnosed during pregnancy. The authors concluded that changes in the RPE during pregnancy could lead to choroidal neovascular membrane formation.5
The presence of antiphospholipid antibody is associated with choroidal disturbance in more than 30% of the patients with ocular changes.6 Our patient had two risk factors for choroidal ischaemia: pre-eclampsia and antiphospholipid antibodies. We believe that this association led to damage to choriocapillaris-Bruch's membrane-RPE complex and secondary choroidal neovacular membrane formation.