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Show Journal of Neuro- Ophthalmologi/ 15( 1): 9- 10, 1995. © 1995 Raven Press, Ltd., New York Pain in Anterior Ischemic Optic Neuropathy Nancy G. Swartz, M. D., Roy W. Beck, M. D., Peter J. Savino, M. D., Robert C. Sergott, M. D., Thomas M. Bosley, M. D., Byron L. Lam, M. D., Mitchell Drucker, M. D., and Barrett Katz, M. D. Purpose: The diagnoses of both anterior ischemic optic neuropathy ( AION) and optic neuritis are clinical ones with significant overlap of symptoms and signs. This study investigates the presence and character of pain at the onset of AION, in order to evaluate this symptom as a differentiating diagnostic feature between optic neuritis and AION. Methods: Forty- one consecutive patients over 45 years of age with a clinical syndrome consistent with AION were questioned about the presence and character of associated pain. Results: Pain was reported by 12% ( 5 of 41) of the patients with AION. This is contrasted with data compiled on 448 patients enrolled in the optic neuritis treatment trial, of whom 92.2% complained of pain. Conclusion: While there is overlap in the incidence and character of pain in AION and optic neuritis, its presence/ absence remains a useful differentiating feature. Key Words: Ischemic optic neuropathy- Optic neuropathy- Pain- Optic neuritis. Both anterior ischemic optic neuropathy ( AION) and optic neuritis are clinical diagnoses based on presentation and findings. Although AION tends to affect older patients than does optic neuritis, there is considerable overlap in the clinical profiles of these two conditions. Several authors have discussed the difficulty and importance of differentiating these two entities for prognostic and therapeutic reasons ( 1- 4). Classically, AION has been considered a painless condition ( 5,6) while the onset of optic neuritis has been thought typically to be accompanied by pain especially associated with eye movements ( 7). To evaluate the specificity of pain as a differentiating diagnostic feature between these two conditions, we designed a study to assess the frequency of pain in patients with AION. We compared this to the frequency of pain in patients with optic neuritis entered into the optic neuritis treatment trial ( ONTT). Manuscript received April 22, 1994; accepted June 21, 1994. From the Neuro- Ophthalmology Service ( N. G. S., P. J. S., R. C. S., T. M. B.), Wills Eye Hospital, Philadelphia, Pennsylvania; Department of Ophthalmology ( R. W. B., M. D.), University of South Florida, Tampa, Florida; Jones Eye Institute ( B. L. L.), University of Arkansas, Little Rock, Arkansas; California Pacific Medical Center ( B. K.), Smith- Kettlewell Eye Research Institute, San Francisco, California, U. S. A. Address correspondence and reprint requests to Dr. Peter J. Savino, Wills Eye Hospital, 900 Walnut St., Philadelphia, PA 19107, U. S. A. METHODS Patients were enrolled prospectively at four geographically separate centers between July 1992 and January 1993. Eligibility criteria for enrollment included the following: clinical syndrome consistent with acute unilateral AION, visual symptoms of 30 days or less, age greater than 45 years, optic disc edema, a visual field defect, and no evidence for giant cell arteritis or other etiology of their findings. The physician completed a questionnaire for each eligible patient ascertaining whether pain had been present in the affected eye. When pain had been present, the date of onset was recorded and the severity, constancy, and relationship to eye movement characterized. The questionnaire was identical to that used to assess pain in the ONTT. 9 10 N. G. SWARTZ ET AL. RESULTS The 41 participating patients were studied in the following centers: Philadelphia, 25 patients; Tampa, FL, 6 patients; Little Rock, AK, 6 patients; San Francisco, 4 patients. In this group, 56% were men. The mean age was 65.7 ± 11.1 years. The mean time interval between onset of visual symptoms and examination was 13.8 ± 9.0 days. Pain was present in 5 of the 41 patients ( 12%), 4 of whom were men. The mean age of patients with pain was 66.4 ± 9.5 years. Pain was characterized as mild by 4 patients and severe by one. Pain was present only on eye movement in one patient, was constant and worsened by eye movement in two patients, and was constant and unrelated to eye movements in two patients. Table 1 compares the characteristics of pain described by the patients in this study to those in the ONTT. In the ONTT, all patients had visual symptoms for 8 days or less. Of the 15 patients with AION in the current study who met that criterion, 2 patients ( 13.3%) had pain. COMMENT Numerous studies have commented on the association of pain with acute optic neuropathies. Rizzo and Lessell ( 1) found an 8% incidence of pain associated with AION in a retrospective study of 143 patients. In Boghen and Glaser's ( 8) review of 29 patients with nonarteritic ischemic optic neuropathy, " several" complained of a foreign body sensation in the involved eye and 4 patients ( 13.8%) reported vague head and eye aches ( one of which was contralateral to the side of visual loss). No patients complained of pain on eye movement. In a study of 48 patients over the age of 35 years followed for acute optic neuropathy not associated TABLE 1. Comparison of the characteristics of pain in AION and optic neuritis AION ONTT patients patients ( N = 41) ( N = 448) Characteristic cular pain present Mild Moderate Severe haracter of pain Constant Constant, worse on eye movement Eye movement only Intermittent, unrelated to eye movement Other % 12 80 0 20 40 40 20 0 0 N 5 4 0 1 2 2 1 0 0 % 92.2 50.1 37.5 12.3 7.3 51.3 35.8 3.4 2.2 N 413 207 155 51 30 212 148 14 9 with multiple sclerosis, Ellenberger and colleagues ( 9) found that 6.25% had complained of a mild pain. The authors state that most patients in this study had AION, although the specific number of patients was not provided. Eagling and coworkers ( 10) studied 40 patients with ischemic optic neuropathy with varied etiologies, including giant cell arteritis and migraine, and found 7 patients ( 17.5%) with pain, none associated with eye movement. We found that pain was present in 12% of our 41 patients and was mild in all but 1 patient. In contradistinction, pain, usually worsened by eye movement, was reported by 92% of patients with optic neuritis enrolled in the ONTT. Since both optic neuritis and AION are clinical diagnoses, it is possible that some patients in our current study had optic neuritis, and some patients in the ONTT had AION. However, because the eligibility criteria for the two studies included only patients with typical clinical profiles of AION and optic neuritis, the number of patients whose disease status was misclassified undoubtedly was small. Performance of ancillary studies ( e. g., neuroim-aging and serologic tests) on patients with either typical optic neuritis or typical AION generally is not useful in defining an etiologic factor ( 1,7). Since optic neuritis commonly is painful, and AION is commonly painless, the presence or absence of pain and its relationship to eye movement is a useful criterion for determining whether a patient's clinical profile is typical or atypical for either optic neuritis or AION and whether additional testing is warranted. REFERENCES 1. Rizzo JF, Lessell S. Optic neuritis and ischemic optic neuropathy: overlapping clinical profiles. Arch Ophthalmol 1991; 109: 1668- 72. 2. Beck RW. Optic neuritis or anterior ischemic optic neuropathy? Arch Ophthalmol 1992; 110: 1357. 3. Lessell S. Optic neuritis. Ophthalmol Ann 1987; 3: 69- 86. 4. Glaser JS. Optic neuritis and ischemic neuropathy: what we thought we already knew. Arch Ophthalmol 1991; 109: 1666- 7. 5. Hayreh SS. Anterior ischemic optic neuropathy. Arch Neurol 1973; 38: 675- 8. 6. Shults WT. Ischemic optic neuropathy: still the ophthalmologist's dilemma. Ophthalmology 1984; 91: 1338- 40. 7. Optic Neuritis Study Group. The clinical profile of optic neuritis: experience of the optic neuritis treatment trial. Arch Ophthalmol 1991; 109: 1673- 8. 8. Boghen DR, Glaser JS. Ischaemic optic neuropathy: the clinical profile and natural history. Brain 1975; 98: 689- 708. 9. Ellenberger C Jr, Keltner JL, Burde RM. Acute optic neuropathy in older patients. Arch Neurol 1973; 28: 182- 5. 10. Eagling EM, Sanders MD, Miller SJH. Ischaemic papillop-athy: clinical and fluorescein and angiographic review of forty cases. Br } Ophthalmol 1974; 58: 990- 1007. / Neuw- Ophthalmol, Vol. 15, No. 1, 1995 |
