By Dr S.S. Gill
Dengue fever has reached an alarming level in Malaysia with health warnings and notices by the Ministry of Health being issued almost daily in the last few months, to the point that nowadays there are even banners put up in residential areas warning people of dengue and its dangers.
It is common knowledge that the infection is spread by the mosquito and to be more precise the Aedes aegypti one. The illness starts acutely with general symptoms of fever, headache, pain behind the eyeballs especially when the eyeballs move, severe muscle and joint ache along with exhaustion. Hence, it is often called “breakbone fever” because of the severity of muscle and joint ache.
Dengue Haemorrhagic Fever is the more severe variety that results in internal bleeding that occurs everywhere from the skin (forming a characteristic rash of bleeding under the skin called petechiae), bleeding into the brain, gut, nose and gums of the teeth.
The most severe form is called Dengue Shock Syndrome. This is the most life threatening. There are currently four different serotypes of dengue, which means there are four different ‘cousins’ amongst the virus. An attack of dengue from one virus serotype gives you a lifetime immunity to that one serotype only.
There is a broad spectrum of eye features that may occur. They are:
MACULAR OEDEMA: A swelling at the central portion of the retina (nerve centre). The person may see a dark patch in the centre of their vision (central scotoma).
MACULAR HAEMORRHAGE: Is a bleeding that occurs in the same area of the retina. This too may result in a similar symptom as Macular Oedema, albeit more severe.
VASCULITIS: Inflammation of the small vessels at the back of the eye (retina). The vision is most affected if the vasculitis is adjacent to the macular area.
ANTERIOR UVEITIS: This is inflammation in the pigmented part of the eye resulting in features of photophobia (inability to tolerate light) and also blurring vision.
EXUDATIVE RETINAL DETACHMENT: Thankfully, this is not that common as the first three. Should this occur, treatment is not the same as retinal detachment due to a retinal tear.
The spectrum of eye involvement may also include subconjunctival haemorrhage (bleeding into the white of the eye as in photo above), optic neuritis (swelling of the optic nerve) and posterior uveitis. If you ever contract dengue fever and have blurring vision, do inform your physician about it.