• Sep 2013
    AAO PPP Committee, Secretary for Quality of Care, Hoskins Center for Quality Eye Care
    Neuro-Ophthalmology/Orbit
    Compendium Type: I

    Clinical Question

    What is the safety and efficacy of optic nerve decompression surgery compared with other treatment or no treatment in people with NAION?

    Literature Search

    The PubMed portion of the literature search for the Cochrane Review was last updated May 23, 2013. None of the 28 new citations met the inclusion criteria of the review.

    Literature search details

    Systematic Review

    Dickersin K, Manheimer E, Li T. Surgery for nonarteritic anterior ischemic optic neuropathy. Cochrane Database of Systematic Reviews. 2012, Issue 1. Art. No.: CD001538. DOI: 10.1002/14651858.CD001538.pub3.

    Methods and Key to Ratings

    Preferred Practice Pattern Clinical Questions should be clinically relevant and specific enough to provide useful information to practitioners. Where evidence exists to support a recommendation for care, the recommendation should be given an explicit rating that shows the strength of evidence. To accomplish these aims, methods from the Scottish Intercollegiate Guideline Network (SIGN)1 and the Grading of Recommendations Assessment, Development and Evaluation (GRADE)2 group are used. All studies used to form a recommendation for care are graded for strength of evidence individually. To rate individual studies, a scale based on SIGN1 is used. GRADE is a systematic approach to grading the strength of the total body of evidence that is available to support recommendations on a specific clinical management issue. Organizations that have adopted GRADE include SIGN, the World Health Organization, the Agency for Healthcare Research and Policy, and the American College of Physicians.3

    SIGN1 Study Rating Scale

    I++

    High-quality meta-analyses, systematic reviews of randomized controlled trials (RCTs), or RCTs with a very low risk of bias

    I+

    Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias

    I-

    Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of bias

    II++

    High-quality systematic reviews of case-control or cohort studies

    High-quality case-control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal

    II+

    Well-conducted case-control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal

    II-

    Case-control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal

    III

    Nonanalytic studies (e.g., case reports, case series)

    GRADE2 Quality Ratings

    Good quality

    Further research is very unlikely to change our confidence in the estimate of effect

    Moderate quality

    Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate

    Insufficient quality

    Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate

    Any estimate of effect is very uncertain

    GRADE2 Key Recommendations for Care

    Strong recommendation

    Used when the desirable effects of an intervention clearly outweigh the undesirable effects or clearly do not

    Discretionary recommendation

    Used when the trade-offs are less certain-either because of low-quality evidence or because evidence suggests that desirable and undesirable effects are closely balanced

    Recommendations for Care

    Summary

    Nonarteritic anterior ischemic optic neuropathy (NAION) is a common cause of acute optic nerve disease in the elderly, resulting in sudden vision loss. The etiology of NAION is unknown. Although various medical interventions have been used to treat NAION, no therapy to date has proven effective. It was proposed in the late 1980s4 that optic nerve decompression surgery might improve vision problems in NAION patients. The surgery entails making slits, or a ‘window’, in the tissue surrounding the optic nerve, allowing cerebrospinal fluid to escape thereby reducing the pressure surrounding the optic nerve. However, the safety and efficacy of this surgery compared with other treatment or no treatment in people with NAION remained in question.

    The Cochrane Review authors identified one systematic review, which found one randomized controlled trial (RCT) comparing optic nerve decompression surgery plus follow-up against follow-up alone in patients with NAION. Enrollment in the Ischemic Optic Neuropathy Decompression Trial (IONDT)5 was stopped earlier than planned due to futility, as the study’s Data and Safety Monitoring Committee (DSMC) determined that continued enrollment was unlikely to lend statistical support for optic nerve decompression surgery. The published results suggest no benefit and possible harms from the surgery.

    (Study Rating Scale I-, Good Quality, Strong Recommendation)

    Discussion

    Nonarteritic anterior ischemic optic neuropathy (NAION) is characterized by a sudden, painless loss of vision in one eye, accompanied by swelling of the optic disc. Some at risk patients experience new NAION in the fellow eye (~14.7%). In general, medical interventions have not proven effective in the treatment of NAION, i.e., corticosteroids or phenytoin sodium.

    The Cochrane Review authors systematically reviewed the evidence for optic nerve decompression surgery for treatment in people with NAION. Studies included in the Cochrane review were RCTs where a) study participants consisted of people with NAION; b) surgical treatment for NAION was compared against any other treatment, including usual care; and c) the study had to report change in visual acuity (VA), change in visual field, NAION occurrence in the fellow eye, adverse events (including perioperative safety), or patient quality of life.

    The Cochrane search identified one RCT that meet these inclusion criteria. The IONDT study5 compared optic nerve decompression surgery with careful follow-up observation against careful observation alone in 258 patients ages 50 years and older. The study subjects had all been diagnosed with NAION within the prior two weeks, and all had BCVA of 20/64 or worse at baseline. The follow-up intervention included an ophthalmologic exam and VA measurement at baseline, follow-up visits at one week, one month, three months, six months, and 12 months, and at six-month intervals thereafter, as well as visual field tests at 12 months and as needed.

    Enrollment in the IONDT was stopped earlier than planned due to futility, as the study’s DSMC determined that continued enrollment was unlikely to lend statistical support for surgery. At six months’ follow-up, 32.0% of surgery patients had improved VA by three or more Snellen lines, compared to 42.6% in the careful follow-up group; at 24 months, 29.4% of surgery patients and 31.0% of follow-up patients had improved VA. These differences were not statistically significant. In a slightly higher proportion of surgery patients, vision worsened – i.e., loss of light perception and diplopia -- at six months compared to follow-up patients, but this difference was not significant. One week after enrollment, 17% of surgery patients reported pain, and 8% of these patients reported diplopia; more serious adverse events in this group included central retinal artery occlusion (one patient), and loss of light perception and loss of vision persisting up to 12 months (two patients).

    Conclusion

    Although the systematic review identified only one RCT comparing optic nerve decompression surgery to careful follow-up observation in NAION patients, the RCT was rated highly in its quality and the strength of its evidence. The trial was stopped early due to futility and concerns regarding safety of the intervention. The published results fail to suggest a benefit from surgery (possibly harm). Participants who received surgery experienced both intraoperative and postoperative adverse events. Further, the review authors believe with reasonable certainty, that a clinically meaningful beneficial effect has not been established with surgical optic nerve decompression and outcomes, defined as an improvement in vision by three or more Snellen lines during a six month follow-up timeframe.

    While it is difficult to discuss with a patient that there is no effective therapy for a potentially blinding disorder, the natural history for observation suggests that NAION may improve spontaneously. Therefore, there is no evidence supporting a role for optic nerve decompression surgery in the treatment of NAION, especially given the potential risks from the procedure. Currently, there is a lack of a clinically meaningful benefit from optic nerve decompression surgery and this should not be considered an effective treatment for NAION.

    References

    1. Scottish Intercollegiate Guidelines Network. SIGN 50: a guideline developer's handbook. Available at: www.sign.ac.uk/methodology/index.html. Accessed May 31, 2013.

    2. Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consenus on rating quality of evidence and strength of recommendations. BMJ 2008;336:924-6.

    3. GRADE Working Group. Organizations that have endorsed or that are using GRADE. Available at: www.gradeworkinggroup.org/society/index.htm. Accessed May 31, 2013.

    4. Sergott RC, Cohen MS, Bosley TM, Savino PJ. Optic nerve decompression may improve the progressive form of nonarteritic ischemic optic neuropathy. Arch Ophthalmol 1989;107:1743-54.

    5. Optic nerve decompression surgery for nonarteritic anterior ischemic optic neuropathy (NAION) is not effective and may be harmful. The Ischemic Optic Neuropathy Decompression Trial Research Group. JAMA 1995;273:625-32.

    Authors and Reviewers

    North American Neuro-Ophthalmology Society (NANOS) Panel Members

    Eric E. Eggenberger, DO, MSEpi

    Leah Levi, MBBS

    Nancy J. Newman, MD

    Preferred Practice Pattern Committee Members

    Stephen D. McLeod, MD, Chair

    David F. Chang, MD

    Robert S. Feder, MD

    Timothy W. Olsen, MD

    Bruce E. Prum, Jr., MD

    C. Gail Summers, MD

    David C. Musch, PhD, MPH, Methodologist

    Secretary for Quality of Care

    Anne L. Coleman, MD, PhD - Director, H. Dunbar Hoskins Jr., MD Center for Quality Eye Care

    Academy Staff

    Jennifer K. Harris, MS

    Nicholas P. Emptage, MAE

    Flora C. Lum, MD

    Approved by:

    Board of Trustees

    September 21, 2013

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    Disclosures

    In compliance with the Council of Medical Specialty Societies' Code for Interactions with Companies, relevant relationships with industry occurring from December 2012 to September 2013 are listed. The Academy complies with the Code in developing PPP Clinical Questions by following the Preferred Practice Patterns and Ophthalmic Technology Assessments: New Relationship with Industry Procedures.

    David F. Chang, MD: No financial relationships to disclose

    Anne L. Coleman, MD, PhD: No financial relationships to disclose

    Eric E. Eggenberger, DO, MSEpi: No financial relationships to disclose

    Robert S. Feder, MD: No financial relationships to disclose

    Leah Levi, MBBS: No financial relationships to disclose

    Stephen D. McLeod, MD: No financial relationships to disclose

    David C. Musch, PhD, MPH: No financial relationships to disclose

    Nancy J. Newman, MD:No financial relationships to disclose

    Timothy W. Olsen, MD: No financial relationships to disclose

    Bruce E. Prum, Jr., MD: No financial relationships to disclose

    C. Gail Summers, MD: No financial relationships to disclose

    Academy Staff: No financial relationships to disclose