The relationship between glaucoma and myopia: the Blue Mountains Eye Study.
OBJECTIVE
To quantify the relationship between myopia and open-angle glaucoma, ocular hypertension (OH), and intraocular pressure (IOP) in a representative older population.


METHODS
Cross-sectional population-based study of 3654 Australians 49 to 97 years of age.


METHODS
Subjects with any myopia (> or =-1.0 diopter [D]) were identified by a standardized subjective refraction and categorized into low myopia (> or =-1.0 D to <-3.0 D) or moderate-to-high myopia (> or =-3.0 D). Glaucoma was diagnosed from characteristic visual field loss, combined with optic disc cupping and rim thinning, without reference to IOP. Ocular hypertension was diagnosed when applanation IOP was greater than 21 mmHg in either eye in the absence of glaucomatous visual field and optic disc changes.


METHODS
General estimating equation models were used to assess associations between eyes with myopia and either glaucoma or OH.


RESULTS
Glaucoma was present in 4.2% of eyes with low myopia and 4.4% of eyes with moderate-to-high myopia compared to 1.5% of eyes without myopia. The relationship between glaucoma and myopia was maintained after adjusting for known glaucoma risk factors, odds ratio (OR) of 2.3, and 95% confidence intervals (CI) of 1.3 to 4.1 for low myopia. It was stronger for eyes with moderate-to-high myopia (OR, 3.3; CI, 1.7-6.4). Only a borderline relationship was found with OH, OR of 1.8 (CI, 1.2-2.9) for low myopia, and OR of 0.9 (CI, 0.4-2.0) for moderate-to-high myopia. Mean IOP was approximately 0.5 mmHg higher in myopic eyes compared to nonmyopic eyes.


CONCLUSIONS
This study has confirmed a strong relationship between myopia and glaucoma. Myopic subjects had a twofold to threefold increased risk of glaucoma compared with that of nonmyopic subjects. The risk was independent of other glaucoma risk factors and IOP.
Mitchell
P
P
Department of Ophthalmology, University of Sydney, Westmead Hospital, NSW, Australia. paulmi@westmed.wh.su.edu.au
Hourihan
F
F
Sandbach
J
J
Wang
J J
JJ
D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000150:complications* / Q000453:epidemiology; D009517:New South Wales / Q000453:epidemiology; D009798:Ocular Hypertension / Q000150:complications* / Q000453:epidemiology; D016017:Odds Ratio; D009898:Optic Disk / Q000473:pathology; D015995:Prevalence; D012307:Risk Factors; D014794:Visual Fields