My patient is a 55-year-old female with a Far North-East Asian heritage and is +5.00 DS in each eye. She complains of headaches and eye aches which seem worse when she reads books just before she goes to bed. I cannot detect any binocular vision problems. What is going on? She has had these symptoms on and off for around 6 months and they seem to be getting worse.

This sounds like it could be chronic closed-angle glaucoma. Many people with angle-closure glaucoma develop it slowly. There are no or subtle symptoms at first, so they don’t know they have it until the damage is severe or unless they have an attack of acute angle-closure. One out of three people (30%) with chronic angle-closure will have a sudden blockage, causing an attack. Which means that two out of every three people with chronic angle-closure won’t.

In cases of chronic closed-angle glaucoma, the intraocular pressure gradually increases as more and more of the drainage angle becomes occluded by the iris. The gradual increase in intraocular pressure means that there are no or very few symptoms. The eye is quiet and the vision is good. One thing to look out for is headaches and eye aches associated with close work, especially reading, in an environment with low lighting. Low light levels result in pupil dilation and more of the drainage angle becomes occluded. In the classic reading position, the chin is down and the head is at an angle of fewer than 90 degrees with the floor. This head position coupled with the effect of gravity on the aqueous causes the iris to bow forward and block even more of the aqueous drainage angle. When reading is stopped and/or the environmental lighting is increased, the iris will move out of the drainage angle, the aqueous outflow is resumed and the symptoms resolve until the next bout of reading.

Risk factors for chronic closed-angle glaucoma include being over 50, female, having an Asian or Intuit heritage and being hyperopic. The patient described above deserves an examination by an ophthalmologist specialising in glaucoma.

The main message here is that not all headaches and eye aches that occur during close work are caused by binocular vision problems. In these cases always consider the possibility of chronic closed-angle glaucoma.