Pregnancy and visual changes

Physiological changes:

• changes in spectacle prescription/difficulty wearing contact lenses
  • reduced production of tear fluid occurs in pregnancy
    • increased myopia (shortsightedness) occurs in about 14% of women
      • caused by reduced tear fluid, altered corneal curvature, increased corneal thickness, and influx of water into the lens
      • refraction disorders are marked by myopization, often not very significant and always regressive within six weeks after the childbirth (2)
    • also changes in tear fluid production may cause contact lens intolerance
      
      
• subconjunctival hemorrhage may occur in about 10% of women during and after delivery
  • requires no measures other than check of blood pressure and baseline blood tests (FBC, clotting)
    
    
• intraocular pressure decreases mildly during pregnancy
  • by 2-3 mmHg, under the influence of hormones (mainly progesterone)
  • no physiological, funduscopically visible changes of the retina arise in the course of a normal pregnancy

Pathological ocular changes:

• ptosis
  • very rare - a few cases of ptosis due to hormonally induced weakening of the attachment of the levator palpebrae have been described
    • benign
    • change must be distinguished from an oculomotor nerve palsy (in which ptosis is accompanied by extraocular muscle weakness leading to diplopia, and by enlargement of the pupil), which requires a further neurological work-up
      
      
• Horner's syndrome (reversible)
  • reported to arise after epidural anesthesia in 0.4% to 2.5% of cases
    
    
• facial nerve palsy
  • probability of development of a transient facial nerve palsy during pregnancy is 38-45 per 100 000 births, or three times higher than at other times
    
    
• central serous chorioretinopathy
  • idiopathic condition involving central retinal detachment
  • arises in 0.008% (4 of 17 000) women in the course of an otherwise unremarkable pregnancy
  • high cortisol concentration during pregnancy is thought to be the main precipitant of this condition
  • usually arises in the third trimester and regresses spontaneously a few weeks to months after delivery
    
    
• hypertensive retinopathy and visual changes in pre-eclampsia/eclampsia
  • pregnancy-related hypertension arises in 5% to 11% of pregnant women
    • 40% to 100% of these patients show signs of hypertensive retinopathy
    • ranging from mild focal retinal vascular spasm to cotton-wool spots and hemorrhages to papilloedema
      • changes, when detected, should prompt further diagnostic and therapeutic steps, even though only 25% to 50% of the affected women are symptomatic (blurred vision, photopsia, visual field defects)
      • retinal changes reflect the severity of hypertension:
        • the most severe changes are seen in (pre-)eclampsia, ranging to reversible serous retinal detachment
      • severe vascular changes in eclampsia, leading to anterior ischemic optic neuropathy (AION) or cortical blindness, are rare
        • cortical blindness and other visual changes resulting from eclampsia may occur
        • generally resolve within hours or days, although subjective visual impairment persists in rare cases

Notes:

• because of pregnancy related changes in the corneal curvature and thickness, refractive surgery should not be performed during pregnancy or in the first year after delivery

Reference:

• Mackensen F, Paulus WE, Max R, Ness T.Ocular changes during pregnancy. Dtsch Arztebl Int. 2014 Aug 18;111(33-34):567-75; quiz 576.
• Millazo S et al. Understanding refraction disorders and oculomotor problems during pregnancy.J Fr Ophtalmol. 2010 May;33(5):368-71.