Received 17 August 2006; received in revised form 21 November 2006; accepted 24 November 2006. published online 28 March 2007.
Objective
To describe the clinical entity of incipient nonarteritic anterior ischemic optic neuropathy (NAION).
Design
Cohort study.
Participants
Fifty-four patients (60 eyes) seen in our clinic from 1973 through 2000.
Methods
At their first visit to our clinic, all patients gave a detailed ophthalmic and medical history and underwent a comprehensive ophthalmic evaluation, color fundus photography, and fluorescein fundus angiography. At each follow-up visit (of 49 patients [55 eyes]), the same ophthalmic evaluation was performed, except for fluorescein fundus angiography.
Main Outcome Measures
Clinical features of incipient NAION.
Results
Mean age (± standard deviation) of the patients was 58.7±15.9 years. Median follow-up time was 6.3 years (interquartile range [IQR], 2.1–8.5). At initial visit, all had optic disc edema (ODE) without any visual loss attributable to NAION. In 55%, the fellow eye had classic NAION; in 25%, incipient progressed to classic NAION (after a median time of 5.8 weeks [IQR, 3.2–10.1]); and in 20%, classic NAION developed after resolution of the first episode of incipient NAION. Patients with incipient, compared with classic, NAION had a greater prevalence of diabetes mellitus (P<0.0001) and lower prevalence of ischemic heart disease (P = 0.046). Patients who progressed to classic NAION versus those who did not were significantly younger (P = 0.025), and their visual acuity worsened in 31% and 0%, respectively, and remained stable in 62% and 98%, respectively; in the eyes with progression, central (in 31%) and peripheral (in 77%) visual fields worsened compared with only 1 eye and 2 eyes, respectively, that did not (P = 0.01 and P<0.0001, respectively); and median time to resolution of ODE in the progressed group was 5.8 weeks (IQR, 4.6–8.7) versus 9.6 weeks (IQR, 6.0–17.7) in those who did not progress.
Conclusions
The results show that incipient NAION is a distinct clinical entity, with asymptomatic ODE and no visual loss attributable to NAION. When a patient seeks treatment with asymptomatic ODE, incipient NAION must be borne in mind as a strong possibility in those who have had classic NAION in the fellow eye, in diabetics of all ages, and in those with high risk factors for NAION; this can avoid unnecessary and expensive investigations.
Available online: March 27, 2007.
1Department of Ophthalmology and Visual Sciences, College of Medicine, University of Iowa, Iowa City, Iowa.
2Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa.
Correspondence to Sohan Singh Hayreh, Department of Ophthalmology and Visual Sciences, University Hospitals & Clinics, 200 Hawkins Drive, Iowa City, IA 52242-1091.
Manuscript no. 2006-921.
Supported by the National Institutes of Health, Bethesda, Maryland (grant no. EY-1151), and in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York.
ABSTRACT