Surgery for nonarteritic anterior ischemic optic neuropathy

Stem Cell Ophthalmology Treatment Study: bone marrow derived stem cells in the treatment of non-arteritic ischemic optic neuropathy (NAION)

Background

Ten patients with bilateral visual loss due to sequential non-arteritic ischemic optic neuropathy (NAION) underwent autologous Bone Marrow Derived Stem Cell (BMSC) therapy within the Stem Cell Ophthalmology Treatment Study (SCOTS). SCOTS is an Institutional Review Board approved clinical study utilizing autologous BMSC in the treatment of optic nerve and retinal diseases that meet inclusion criteria.

Methods

The average age of the patients treated was 69.8 years. The average duration of visual loss in eyes treated was 9.8 years and ranged from 1 to 35 years. Affected eyes were treated with either retrobulbar, subtenons and intravenous BMSC or, following vitrectomy, intra-optic nerve, subtenons and intravenous BMSC. The primary outcome was visual acuity as measured by Snellen or converted to LogMAR.

Results

Following therapy in SCOTS, 80% of patients experienced improvement in Snellen binocular vision (P=0.029) with 20% remaining stable; 73.6% of eyes treated gained vision (P=0.019) and 15.9% remained stable in the post-operative period. There was an average of 3.53 Snellen lines of vision improvement per eye with an average 22.74% and maximum 83.3% improvement in LogMAR acuity per eye. The average LogMAR change in treated eyes was a gain of 0.364 (P=0.0089). Improvements typically manifested no later than 6 months post procedure.

Conclusions

The use of BMSC in the Stem Cell Ophthalmology Treatment Study achieved meaningful visual improvements in a significant percentage of the NAION patients reported. Improvements typically manifested no later than 6 months post-procedure. Duration of visual loss did not appear to affect the ability of the eyes to respond to treatment. Possible mechanisms by which visual improvement occurred may include BMSC paracrine secretion of proteins and hormones, transfer of mitochondria, release of messenger RNA or other compounds via exosomes or microvesicles and neuronal transdifferentiation of the stem cells.

Surgery for nonarteritic anterior ischemic optic neuropathy

BACKGROUND

Nonarteritic anterior ischemic optic neuropathy (NAION) is characterized by sudden and painless loss of vision in the eye, accompanied by pallid swelling of the optic disc. Its etiology is unknown and no medical therapy has been proven effective in treating this condition. Optic nerve decompression surgery, a proposed treatment for NAION, involves making two or more slits or a window in the tissue surrounding the optic nerve, thereby allowing cerebrospinal fluid to escape, and theoretically reducing the pressure surrounding the optic nerve.

OBJECTIVES

The objective of this review was to assess the safety and efficacy of surgery compared with other treatment or no treatment in people with NAION.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 10), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2014), EMBASE (January 1980 to October 2014), PubMed (1948 to October 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 23 October 2014.

SELECTION CRITERIA

All randomized trials of surgical treatment of NAION were eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

From full-text copies of all reports from relevant trials, one author extracted data which were verified by another author. No data synthesis was required.

MAIN RESULTS

The one included trial, in which 258 participants were randomized, was stopped early for futility. At the time of the 24-month report the follow-up rate was 95.3% for six months and 67.4% for 24 months (174 participants; 89 careful follow-up and 85 surgery). There was no evidence of a benefit of surgery on visual acuity. Measurements of visual acuity and visual fields were performed by a technician masked to the treatment received. At six months 32.0% of the surgery group had improved visual acuity by 3 or more lines compared with 42.6% of the careful follow-up group (unadjusted risk ratio (RR) 0.75, 95% confidence interval (CI) 0.54 to 1.04). At 24 months 29.4% of the surgery group had improved compared with 31.0% of the careful follow-up group (unadjusted RR 0.95, 95% CI 0.60 to 1.49). Participants who underwent surgery more often lost 3 or more lines of visual acuity in the study eye, although the increased risk was not statistically significant. At six months 18.9% in the surgery group had worsened visual acuity in the study eye compared with 14.8% in the careful follow-up group (RR 1.28; 95% CI 0.73 to 2.24). At 24 months 20.0% in the surgery group had worsened visual acuity in the study eye compared with 21.8% in the careful follow-up group (RR 0.92; 95% CI 0.51 to 1.64). Participants who received surgery experienced both intraoperative and postoperative adverse events, including central retinal artery occlusion during surgery and light perception vision at six months (one participant); and immediate loss of light perception following surgery and loss of vision that persisted to the 12-month visit (two participants). In the careful follow-up group, two participants had no light perception at the six-month follow-up visit; one of these had improved to light perception at 12 months. Pain was the most common adverse event in the surgery group (17% in surgery group versus 3% in the careful follow-up group at one week). Diplopia (double vision) was the next most common complication (8% in the surgery group versus 1% in the careful follow-up group at one week); at three months there was no statistically significant difference in proportion of participants with diplopia between the two groups.

AUTHORS' CONCLUSIONS

The only eligible trial provided no evidence of a beneficial effect of optic nerve decompression surgery for NAION. Future research should focus on increasing our understanding of the etiology and prognosis of NAION. New treatment options should be examined in the context of randomized clinical trials.

Hypotension-induced blindness in haemodialysis patients

Hypotension is a commonly encountered complication in haemodialysis patients and is a significant cause of morbidity and mortality. Bilateral visual loss in dialysis induced hypotension remains poorly recognized as a complication by both renal physicians and ophthalmologists. We report 2 cases of patients on renal dialysis who suffered severe longstanding hypotension with bilateral non-arteritic anterior ischaemic optic neuropathy. Both patients experienced bilateral loss of vision over a short time period. We feel that physicians must be aware of patients complaining of painless visual loss in this high risk group, as control of blood pressure may be the most important factor in prevention of this visually devastating condition.

Radial optic neurotomy as a treatment for anterior ischemic optic neuropathy secondary to optic disc drusen

Importance: Radial optic neurotomy (RON) was first described by Opremcak as a treatment for patients with central retinal vein occlusion (CRVO). The most common cause of visual loss in patients with optic disc drusen is nonarteritic anterior ischemic optic neuropathy (NAION). The pathogenesis of nonarteritic anterior ischemic optic neuropathy associated with optic disc drusen is assumed to be similar to the compartment-like syndrome described by Opremcak in the case of central retinal vein occlusion.

Observation: An 82-year-old male with bilateral optic disc drusen presented with bilateral visual loss and severe visual field defects consistent with nonarteritic anterior ischemic optic neuropathy. A radial optic neurotomy was performed to treat the most affected eye. Postoperatively, significant and persistent improvement of visual acuity and improved automated perimetry were observed in the operated eye.

Conclusion: Optic nerve head decompression by radial optic neurotomy could be a treatment option in patients with nonarteritic anterior ischemic optic neuropathy associated with optic disc drusen and severe visual field defects.