Determinants of intraocular pressure and its association with glaucomatous optic neuropathy in Chinese Singaporeans: the Tanjong Pagar Study.
OBJECTIVE
To examine the relationship between intraocular pressure (IOP), anthropomorphic, demographic, socioeconomic, systemic, and ocular factors and glaucomatous optic neuropathy (GON) in Chinese people.


METHODS
Chinese people (n = 2000), aged 40 to 79 years, were selected from the Singapore electoral register. Of the 1717 considered eligible for examination, 1232 participated, representing a response rate of 71.8%. IOP was estimated with Goldmann applanation tonometry. The drainage angle was assessed with static and dynamic gonioscopy. The optic nerve was examined at high magnification through a dilated pupil with a fundus contact lens or a +78-D lens. Static automated visual field testing was performed on subjects with suspected glaucoma. GON was diagnosed on the basis of structural and functional abnormalities of the optic nerve.


RESULTS
The main independent determinants of higher IOP were higher systolic blood pressure (P < 0.001), quadrants of any peripheral anterior synechiae (PAS, P = 0.02) and width of the drainage angle (P = 0.049). A 100- micro m increase in corneal thickness was associated with an increase in mean IOP of 1.5 to 1.8 mm Hg (P < 0.001). Odds of GON increased 1.2 times per 1-mm Hg increase in screening IOP. A clear association between corneal thickness and GON was not identified.


CONCLUSIONS
Clinical IOP estimates are related to systolic blood pressure and corneal thickness. Variation in IOP with angle width may suggest that trabecular compaction significantly contributes to causes of the increase in IOP, independent of angle-closure. GON is an IOP-related phenomenon among Chinese Singaporeans.
Foster
Paul J
PJ
Singapore National Eye Centre and Singapore Eye Research Institute, Singapore.
Machin
David
D
Wong
Tien-Yin
TY
Ng
Tze-Pin
TP
Kirwan
Jim F
JF
Johnson
Gordon J
GJ
Khaw
Peng T
PT
Seah
Steve K L
SK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001794:Blood Pressure; D003315:Cornea / Q000033:anatomy & histology; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009900:Optic Nerve / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology*; D012846:Singapore / Q000453:epidemiology; D014065:Tonometry, Ocular; D058609:Visual Field Tests; D014794:Visual Fields