Natural History of Nonarteritic Anterior Ischemic Optic Neuropathy

Visual acuity and quantitative perimetry (Octopus Program 32) testing was performed in the acute (< 30 days after onset) and convalescent (> 3 months after onset) phases of disease in 27 patients with untreated NAION. Initial group mean acuity and sensitivity loss were compared to final values using the t test. Proportions of patients demonstrating a change of > 2 lines acuity or > 2 dB mean sensitivity were calculated. Patients were classified as either 'progressive' (n = 6) or 'stable' (n = 21) for purposes of additional subgroup analysis. There was no significant change in group mean visual acuity or field over time. Overall, significant worsening occurred in 11.1% for visual acuity and 22.2% for visual field; improvement occurred in 23.8% for acuity and 24.0% for field. Of 21 'stable' patients, none worsened for acuity and 4.7% showed late worsening of field; 31.3% showed significant improvement for acuity and 31.6% for field. No ''progressive'' patients demonstrated worsening or improvement after the initial progressive phase.

Journal of Neuro- Ophihalmology 14( 2): 66- 69, 1994. © 1994 Raven Press, Ltd., New York Natural History of Nonarteritic Anterior Ischemic Optic Neuropathy Anthony C. Arnold, M. D., and Robert S. Hepler, M. D. Visual acuity and quantitative perimetry ( Octopus Pro­gram 32) testing was performed in the acute (< 30 days after onset) and convalescent (> 3 months after onset) phases of disease in 27 patients with untreated NAION. Initial group mean acuity and sensitivity loss were com­pared to final values using the t test. Proportions of pa­tients demonstrating a change of > 2 lines acuity or > 2 dB mean sensitivity were calculated. Patients were clas­sified as either " progressive" ( « = 6) or " stable" ( n = 21) for purposes of additional subgroup analysis. There was no significant change in group mean visual acuity or field over time. Overall, significant worsening occurred in 11.1% for visual acuity and 22.2% for visual field; improvement occurred in 23.8% for acuity and 24.0% for field. Of 21 " stable" patients, none worsened for acuity and 4.7% showed late worsening of field; 31.3% showed significant improvement for acuity and 31.6% for field. No " progressive" patients demonstrated worsening or improvement after the initial progressive phase. Key Words: Nonarteritic anterior ischemic optic neurop­athy- Natural history- Automated quantitative perim­etry. In nonarteritic anterior ischemic optic neuropa­thy ( NAION), the degree of visual loss has been characterized as " monotonously stable" ( 1). There is, however, a well- documented subgroup of pa­tients in which initial visual loss is followed by gradual or episodic deterioration over several weeks (" progressive" NAION) ( 2- 4). Addition­ally, retrospective analysis of visual acuity data in a large series of untreated patients ( preliminary ab­stract) ( 5) has suggested a significant incidence of improvement without therapy; spontaneous re­covery of acuity has similarly been noted in iso­lated cases of the progressive form ( 6,7). Visual acuity is, however, a limited measure of optic nerve function, and similar detailed analysis of vi­sual field data has not been performed. We present sequential quantitative perimetry and visual acuity data in 27 cases of untreated NAION. From the UCLA Optic Neuropathy Center, Jules Stein Eye Institute, Department of Ophthalmology, University of Califor­nia, Los Angeles, California, U. S. A. This study was supported in part by the Charles Kenneth Feldman Fund, Los Angeles, California. This paper was presented at the Tenth International Neuro- Ophthalmology Society, Freiburg, Germany, June 5- 9, 1994. Address correspondence and reprint requests to Dr. Anthony C. Arnold, Jules Stein Eye Institute, 100 Stein Plaza, UCLA, Los Angeles, California 90024- 7005, U. S. A. PATIENTS AND METHODS Visual acuity and quantitative perimetry ( Octo­pus Program 32) testing were performed in 22 cases of acute NAION seen at the Jules Stein Eye Institute from 1989 to 1992. All patients were age 45 or older, with recent ( within 30 days) onset of monocular visual loss, and the presence of an af­ferent pupillary defect, optic disc swelling, and vi­sual field loss consistent with NAION. No patients had evidence of prior visual loss in the same eye, systemic symptoms suggestive of vasculitis ( in­cluding temporal arteritis) or demyelinating dis­ease, or elevation of Westergren sedimentation rate greater than 40 mm/ h. Two patients received oral prednisone, Patient 22 at 60 mg per day for 4 days and Patient 25 tapering from 80 mg per day to no therapy in 8 days; no other patients received treatment. Follow- up acuity and perimetry testing by the same technique were performed at least 3 months after initial evaluation. Retrospective re- 66 NAION NATURAL HISTORY 67 view of 140 cases of NAION seen at the same in­stitute from 1983 to 1994 revealed five additional untreated patients who met the same criteria. Of the total 27 patients included, 22 were male and 5 female, with mean age 64.7 years ( range: 48 to 85). Initial visual acuity and perimetry testing was performed from 3 to 26 days ( mean 11.9 days) after onset of symptoms; final testing was accom­plished from three to 76 months ( mean 12.6 years) after onset. Initial group mean values for visual acuity and mean sensitivity loss were compared to final group mean values using the Student's f test. In order to estimate the effect of long- term fluctuation and learning on perimetry data in this patient group, the change in group mean sensitivity loss in fellow eyes over time was calculated (- 1.00 dB). Based on this value, a 2- dB alteration in mean sensitivity loss was used as the criterion for definite change. The proportions of patients demonstrating a change of > 2 lines Snellen acuity of > 2 dB mean sensitivity loss were calculated. Patients sustaining additional visual loss ( by either acuity or field cri­teria) within 2 months after initial symptom onset were classified as progressive NAION, with the remaining patients considered stable NAION; sim­ilar calculations for visual acuity and mean sensi­tivity loss were performed within each of these subgroups. RESULTS Patient profiles, visual acuity, and visual field data are summarized in Table 1. Change in overall group mean acuity from initial to final testing was + 0.37 lines and in mean sen­sitivity loss + 0.57 dB, neither statistically signifi­cant at the P < .05 level. Three of 27 ( 11.1%) dem­onstrated significant (> 2 line) decrease in Snellen acuity, with 6 of 27 ( 22.2%) showing significant (> 2 dB) increase in mean sensitivity loss. Five of 21 ( 23.8%) increased in acuity and 6 of 25 ( 24.0%) de­creased in mean sensitivity loss ( six patients with initial acuity of 20/ 20 and two with initial mean sensitivity loss of less than 2 dB were excluded because improvement from these levels was lim­ited). Six patients ( 22.2%) were considered progres­sive ( Patients 22 to 27); three suffered a second discrete episode of visual loss within 1 month of TABLE 1. Summary of patient profiles and visual data Pt no. 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Age 58 63 70 68 62 85 61 67 52 69 67 64 62 48 56 65 76 60 63 69 69 48 67 74 68 79 57 Sex M M M M F M M M F M M M M M M F M M M M M M F F M M M Eye OS OD OD OD OS OS OS OS OS OS OS OD OS OS OD OD OD OS OS OS OD OD OD OS OD OS OS T1 ( days) 20 21 21 7 7 14 6 19 5 4 6 10 24 11 6 15 12 13 26 4 4 3 20 18 9 9 7 T2 ( months) 61 33 11 13 9 3 6 5 4 4 4 23 12 8 4 4 4 4 5 16 9 6 3 6 76 4 3 VA1 5/ 400 20/ 300 20/ 20 20/ 20 20/ 70 20/ 70 20/ 30 HM 20/ 300 20/ 30 20/ 40 20/ 20 20/ 60 20/ 20 20/ 20 10/ 400 20/ 400 20/ 40 20/ 200 HM 20/ 20 20/ 20 20/ 20 20/ 400 20/ 25 20/ 400 20/ 20 VA2 15/ 400 20/ 60 20/ 20 20/ 30 20/ 40 20/ 50 20/ 25 20/ 400 20/ 200 20/ 25 20/ 30 20/ 20 20/ 20 20/ 20 20/ 15 20/ 30 20/ 200 20/ 50 20/ 400 5/ 400 20/ 20 20/ 60 20/ 20 5/ 400 1/ 400 5/ 400 20/ 40 VF1 16.16 15.80 5.50 10.30 0.80 13.50 18.60 18.20 14.10 14.70 4.60 4.00 5.00 8.30 0.50 21.70 17.30 22.40 7.10 13.83 11.63 19.67 7.90 12.29 11.15 14.40 24.80 VF2 11.03 17.60 5.00 10.90 0.20 14.20 17.80 19.30 13.10 13.80 1.00 5.40 6.40 13.50 0.00 1.10 15.00 20.10 7.10 10.80 13.57 22.21 21.30 22.25 21.26 21.90 24.70 VF1A 0.52 2.10 8.10 0.50 0.10 0.40 5.40 0.90 2.20 16.30 1.90 2.90 0.00 0.20 0.50 12.30 1.10 3.10 0.90 2.36 3.14 21.92 7.90 1.05 21.92 3.70 3.90 VF2A 0.26 0.10 7.60 0.60 0.10 0.30 1.50 2.40 0.00 12.50 0.10 6.40 0.00 0.80 0.10 2.10 0.10 2.20 0.20 1.58 1.58 18.93 14.80 1.93 20.88 0.10 3.10 T, time: Time 1 refers to interval from symptom onset to initial testing; Time 2 refers to interval from symptom onset to final testing. VA, visual acuity. VF, visual field: VF1 and VF2 refer to initial and final mean sensitivity loss, in decibels; VF1A and VF2A refer to initial and final mean sensitivity loss, in decibels, in contralateral eye. / Neuro- OphtMmol, Vol. 34, No. 2, 1994 68 A. C. ARNOLD AND R. S. HEPLER initial symptoms, with three showing gradual or poorly defined further loss during the month fol­lowing initial symptoms. None showed significant worsening or improvement after the progressive phase of visual loss. Of the 21 patients considered stable, change in group mean acuity from initial to final testing was + 1.66 Snellen lines and in mean sensitivity loss was - 1.34 dB. None of the 21 significantly de­creased in acuity, while one of 21 ( 5.7%) showed a late increase in mean sensitivity loss ( probable " re­current" NAION). Five of 16 ( 31.3%) demon­strated > 2 line increase in acuity and six of 19 ( 31.6%) showed > 2 dB decrease in mean sensitiv­ity loss. DISCUSSION The clinical course of untreated NAION has been incompletely studied. The majority of reports concerning natural history describe visual acuity, a parameter that may not accurately represent over­all optic nerve function. In all studies, the majority of patients maintained stable acuity, with figures for deterioration by at least 2 lines Snellen acuity ranging from 0 to 24% and for spontaneous im­provement ranging from 0 to 50% ( 1,5,8- 16). In a recent preliminary abstract, Movsas and col­leagues ( 5) reported deterioration in 44 of 242 pa­tients ( 18%) and improvement in 53 of 242 ( 21.9%). Isolated cases of spontaneous improvement in pa­tients who had previously deteriorated ( progres­sive NAION) have recently been documented ( 6,7). Visual field data has occasionally been provided, but quantitative analysis has been limited. Hayreh and Podhajsky ( 11) reported qualitative deteriora­tion on Goldmann perimetry in 1 of 11 patients ( 9.1%) and improvement in 5 of 11 ( 45.5%). Boghen and Glaser ( 1) noted deterioration of visual field in 11 of 37 patients ( 29.7%) and Repka and associates ( 12) 3/ 83 ( 3.6%); neither described sig­nificant improvement. There has been no detailed study of quantitative static perimetry in untreated NAION. Our data corroborate prior reports of deteriora­tion in both visual acuity ( 11.1% and visual field ( 22.2%) and confirm a subgroup of patients who demonstrate spontaneous improvement in both acuity ( 23.8%) and fields ( 24.0%) over time. We did not document spontaneous improvement in any case of progressive NAION. We chose 2 dB as the minimum criterion for visual field change in order to retain sensitivity for detection of change while taking into account both learning effect and nor­mal long- term fluctuation ( mean increase of 1.00 dB in contralateral eyes). If the criterion is modi­fied by requiring a change of 2 dB greater than the change in the corresponding fellow eye, the value for deterioration increases to 37.0% ( 10/ 27 cases) and for spontaneous improvement decreases to 12.0% ( 3/ 25 cases). Quantitative perimetry is a better measure of overall optic nerve damage than visual acuity, which may vary widely with minor changes in cen­tral function. Our data provide strong evidence in support of the significant incidence of spontane­ous recovery in nonprogressive NAION that has been suggested by previous reports of acuity and qualitative field improvement. Enthusiasm gener­ated by improved optic nerve function after optic nerve sheath decompression for nonprogressive NAION must be tempered by the knowledge that significant numbers may improve spontaneously ( 17). The lower rate of such improvement in un­treated progressive cases makes therapeutic suc­cess in this form of the disease, ( 18) as originally proposed by Sergott and associates ( 14), more credible. The controlled data generated by the Ischemic Optic Neuropathy Decompression Trial ( IONDT) may help to clarify these issues. REFERENCES 1. Boghen DR, Glaser JS. Ischaemic optic neuropathy. The clinical profile and natural history. Brain 1975; 98: 689- 708. 2. Beck RW, Savino PJ, Schatz NJ, Smith CH, Sergott RC. Anterior ischaemic optic neuropathy: recurrent episodes in the same eye. Br } Ophthalmol 1983; 67: 705- 9. 3. Borchert M, Lessell S. Progressive and recurrent nonar-teritic anterior ischemic optic neuropathy. Am ] Ophthalmol 1988; 106: 499- 9. 4. Kline LB. Progression of visual defects in ischemic optic neuropathy. Am ] Ophthalmol 1988; 106: 199- 203. 5. Movsas T, Kelman SE, Elman MJ, Miller NR, Dickersin K, Min Y- L. The natural course of non- arteritic ischemic optic neuropathy. 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