RNFL thickness (left) and deviation maps (right) show the increased vulnerability to glaucoma brought about by high myopia. The top images are a -6.75D myopia with an axial length of 27.26mm; at bottom is a -2.00D myopia with axial length of 26.61mm. Photo: Andrew Rouse, Lauren Sabol, Tej Ramdass. Click image to enlarge.

In China, the list of ocular and systemic parameters associated with open-angle glaucoma (OAG) and previous longitudinal studies were only investigated within a five-year period. A recent study has reviewed the data over a 10-year period and has noted that high myopia was associated with a 7.3-fold increased incidence of the disease as compared with emmetropic eyes. The average 10-year incidence of OAG was 3.0%—comparable with studies in other ethnicities over the same time.

The study reviewed data 2,695 individuals in the Beijing Eye Study who were re-examined in 10 years’ time. Incident OAG was found in 75 participants among 2494 individuals free of glaucoma at baseline. The 10-year OAG incidence increased from 1.8 in individuals aged 40 to 49 years old, to 5.9% in participants ages 70 and over. The study classified eyes as emmetropia/hyperopic (>-1D), low myopia: ≤-1D and >-3 D), moderate myopia (≤-3D and >-6D) and high myopia ≤-6D)

The risk of developing OAG increased by a factor of 1.72 for each mm higher axial length. OAG incidence was highest in the high myopia group (13.3%; odds ratio, OR: 7.3), followed by the moderate myopia group (8.1%; OR: 4.2) and the low myopia group (6.2%; OR: 3.2).

OAG additionally increased by a factor of 1.18 for each mm Hg higher IOP at baseline, by a factor of 6.1 for each 1/10 increase in vertical cup-to-disc ratio (CDR), in addition to a factor of 1.06 for each year higher in age. It decreased by a factor of 0.98 for each µm thicker central corneal thickness (CCT).

The findings believed that their findings “should be of importance to clinical protocols and screening strategies.”