Ischemic optic neuropathy

Comparison of Visual Outcomes of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients with and without Diabetes Mellitus

PURPOSE

Diabetic patients have a greater risk of nonarteritic anterior ischemic optic neuropathy (NAION) than nondiabetic patients. We compare visual outcomes, prevalence of bilateral/sequential ION, and predictors of visual outcomes in NAION between diabetic and nondiabetic patients.

DESIGN

Case-control study.

PARTICIPANTS

All 231 patients with NAION seen by the Neuro-Ophthalmology Service, Wilmer Eye Institute, between 2002 and 2011 were screened for study inclusion.

METHODS

Patients presenting within 4 weeks of symptom onset (30 with diabetes mellitus, 62 control patients) were included in baseline demographic assessments of vascular risk factors. Interval and final visual outcomes (logarithm of the minimum angle of resolution [logMAR] visual acuity [VA]) were evaluated in the 81 patients in this group with clinical follow-up for ≥3 months, and population average logistic regression models were used to determine risk factors for worse visual outcomes.

MAIN OUTCOME MEASURES

Visual acuity at last follow-up.

RESULTS

The median follow-up duration was 38.7 weeks in diabetic patients and 52.9 weeks in nondiabetic patients. The majority (92.5%) of patients presented within 2 weeks of symptom onset. In nondiabetic patients, the most prevalent risk factor for NAION was hyperlipidemia (62.9%); for diabetic patients, NAION risk factors included hypertension (83.3%), hyperlipidemia (83.3%), and small cup-to-disc ratio (63.3%). Sequential NAION occurred in 36.8% of diabetic patients and 20.9% of nondiabetic patients. At last follow-up, 48% of diabetic and 62% of nondiabetic patients had VA better than 20/40. Similar proportions of diabetic and nondiabetic patients (8 [27%] diabetic and 14 [22.5%] nondiabetic patients) recorded a final follow-up vision of 1.0 logMAR or worse at a minimum of 3 months. Ischemic heart disease (odds ratio [OR], 7.21; P < 0.001) and greater age (OR, 1.05; P = 0.045) were associated with increased risk for final VA <20/200 in the multiple regression model (OR, 4.35; P = 0.011).

CONCLUSIONS

The VA at presentation and at final follow-up in diabetic patients with NAION were not significantly different from nondiabetic controls, although diabetic patients had a higher prevalence of cardiovascular risk factors. Ischemic heart disease and greater age, but not diabetes, independently correlated with worse VA outcome.

Optic neuropathies: characteristic features and mechanisms of retinal ganglion cell loss

Optic neuropathy refers to dysfunction and/or degeneration of axons of the optic nerve with subsequent optic nerve atrophy. A common feature of different optic neuropathies is retinal ganglion cell (RGC) apoptosis and axonal damage. Glaucoma and optic neuritis are the two major degenerative causes of optic nerve damage. Here, we review the anatomy and pathology of the optic nerve, and etiological categories of optic neuropathies, and discuss rodent models that can mimic these conditions. Electrophysiology can reveal signature features of RGC damage using the pattern electroretinogram (PERG), scotopic threshold response (STR) and photopic negative response (PhNR). The amplitude of the visual evoked potential (VEP) also reflects RGC axonal damage. The neurotrophin-mediated survival pathways, as well as the extrinsic and intrinsic cell apoptotic pathways, play a critical role in the pathogenesis of RGC loss. Finally, promising neuroprotective approaches based on the molecular signaling are analyzed for the treatment of optic neuropathies.

Effects of orally administered moxaverine on ocular blood flow in healthy subjects

BACKGROUND

To investigate the effect of orally administered moxaverine (Kollateral forte®) on ocular blood flow in young healthy subjects.

METHODS

Sixteen healthy subjects (eight male/eight female) aged between 20 and 32 years were included in this placebo-controlled, double-masked, two-way crossover study. Volunteers received 900 mg moxaverine-hydrochloride administered orally in three equal doses or placebo identical in appearance on 2 study days. Outcome variables were measured at baseline and 5 h after first drug administration. Laser Doppler flowmetry was used to assess choroidal and optic nerve head blood flow. Blood velocities in the retrobulbar vessels were measured with color Doppler imaging.

RESULTS

Neither moxaverine nor placebo changed mean arterial pressure or intraocular pressure. Neither moxaverine nor placebo had an effect on choroidal (moxaverine: by 9.5 ± 17.2 %, placebo 3.8 ± 18.8 %, p = 0.54 between groups) or optic nerve head blood flow (moxaverine: 4.8 ± 10.4 %, placebo: 1.8 ± 10.9 %, p = 0.52 between groups). Similarly, administration of moxaverine did not change blood flow velocities or calculated resistance index in the retrobulbar vessels compared to placebo.

CONCLUSION

The data of the present study indicate that orally administered moxaverine does not increase ocular blood flow. This is in contrast to previous findings, where parenteral administration of moxaverine lead to a significant increase in choroidal blood flow and blood flow velocities in the retrobulbar vessels. The reason for these differing results is unclear, but may be related to the low bioavailability after oral administration.

Substantial adverse association of visual and vascular comorbidities on visual disability in multiple sclerosis

Background: Visual comorbidities are common in multiple sclerosis (MS) but the impact of visual comorbidities on visual disability is unknown.

Objective: We assessed the impact of visual and vascular comorbidities on severity of visual disability in MS.

Methods: In 2006, we queried participants of the North American Research Committee on Multiple Sclerosis (NARCOMS) about cataracts, glaucoma, uveitis, hypertension, hypercholesterolemia, heart disease, diabetes and peripheral vascular disease. We assessed visual disability using the Vision subscale of Performance Scales. Using Cox regression, we investigated whether visual or vascular comorbidities affected the time between MS symptom onset and the development of mild, moderate and severe visual disability.

Results: Of 8983 respondents, 1415 (15.9%) reported a visual comorbidity while 4745 (52.8%) reported a vascular comorbidity. The median (interquartile range) visual score was 1 (0–2). In a multivariable Cox model the risk of mild visual disability was higher among participants with vascular (hazard ratio [HR] 1.45; 95% confidence interval [CI]: 1.39–1.51) and visual comorbidities (HR 1.47; 95% CI: 1.37–1.59). Vascular and visual comorbidities were similarly associated with increased risks of moderate and severe visual disability.

Conclusions: Visual and vascular comorbidities are associated with progression of visual disability in MS. Clinicians hearing reports of worsening visual symptoms in MS patients should consider visual comorbidities as contributing factors. Further study of these issues using objective, systematic neuro-ophthalmologic evaluations is warranted.