Corneal thickness as a risk factor for visual field loss in patients with preperimetric glaucomatous optic neuropathy.
OBJECTIVE
To determine whether central corneal thickness (CCT) is a risk factor for visual field loss development among patients diagnosed with preperimetric glaucomatous optic neuropathy (GON).


METHODS
Observational cohort study.


METHODS
The study included 98 eyes of 98 patients with GON, with a mean follow-up time of 4.3 +/- 2.7 years. Diagnosis of GON was based on masked assessment of optic disk stereophotographs. All patients had normal standard automated perimetry visual fields at baseline. Criteria for visual field abnormality were derived from a prior study. Several clinical factors (CCT, intraocular pressure, vertical cup-to-disk ratio, refraction, age, gender, family history of glaucoma, high blood pressure, cardiovascular disease, and migraine) were investigated to ascertain whether there is an association with development of repeatable visual field loss. Cox proportional hazards models were used to obtain hazard ratios (HR) and identify factors that predicted which individuals developed glaucomatous visual field loss during the follow-up period.


RESULTS
Thirty-four patients (35%) developed repeatable visual field abnormality during follow-up. In multivariate analysis, risk factors that predicted the development of visual field loss were a thinner CCT (adjusted HR = 1.62/40 microm thinner; P =.023; 95% confidence interval [CI]: 1.07-2.45), higher baseline intraocular pressure (adjusted HR = 1.07/mm Hg; P =.022; 95% CI: 1.01-1.14), and larger baseline vertical cup-to-disk ratio (adjusted HR = 1.63/0.1 larger; P =.009; 95% CI: 1.13-2.35). The mean +/- standard deviation CCT of GON patients who developed visual field loss was 543 +/- 36 microm compared with 565 +/- 35 microm of those who did not develop visual field abnormalities (P =.005, Student t test).


CONCLUSIONS
Central corneal thickness is a risk factor for development of visual field loss among patients diagnosed with preperimetric GON. It is important to consider CCT when establishing target intraocular pressure of patients with GON.
Hamilton Glaucoma Center, Department of Ophthalmology, University of, California, San Diego, California 92093, USA.
Felipe A
FA
Medeiros
Pamela A
PA
Sample
Linda M
LM
Zangwill
Christopher
C
Bowd
Makoto
M
Aihara
Robert N
RN
Weinreb
D015331:Cohort Studies; D003315:Cornea / Q000473:pathology*; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D010781:Photography; D016016:Proportional Hazards Models; D012307:Risk Factors; D014786:Vision Disorders / Q000175:diagnosis*; D058609:Visual Field Tests; D014794:Visual Fields