Pathophysiology: Raised intrathoracic and/or intra-abdominal pressure increases venous pressure in the eye, resulting in intra-ocular bleeding.
Clinical:
(1) sudden onset of visual loss after some form of straining
(2) the visual loss may be unilateral, or bilateral and asymmetrical
(3) the visual loss may be limited to central vision
Precipitating activities:
(1) coughing
(2) vomiting
(3) sneezing
(4) straining at stool in constipation
(5) lifting
(6) sexual intercourse
(7) Valsalva maneuver
(8) aerobic exercise
(9) inflating balloons
(10) weight-lifting
(11) during mechanical ventilation
Types of hemorrhage:
(1) beneath the internal limiting membrane of the retina
(2) subretinal
(3) retinal
(4) intra-vitreal bleeding
Ophthalmologic findings:
(1) A focus of hemorrhage can usually be seen, often in the region of the macula.
(2) If the bleeding is beneath the internal limiting membrane, then a fluid level may be seen as the red blood cells settle.
(3) Fluorescein angiography can help visualize the changes.
Clinical course:
(1) Vision usually returns to normal spontaneously over days to weeks.
(2) If the hemorrhage is beneath the internal limiting membrane, recovery can be hastened by using a laser to puncture the collected pocket of blood, allowing it to drain.
