Short-wavelength automated perimetry in patients with migraine

Case report: Findings of automated perimetry during a migraine episode in a patient with glaucoma

Comorbidities like glaucoma and migraine are often observed among middle-aged individuals, especially women. Herein, we report a rare case of a patient who underwent automated perimetry during a migraine attack. A 52-year-old woman with a 1-year history of blurred vision in the nasal field of her right eye visited Miyoshi Eye Clinic. The intraocular pressures of the right and left eyes were 22 and 24 mm Hg, respectively. Retinal imaging revealed a retinal nerve fiber defect in the temporal superior macula with corresponding thinning of the superior ganglion cell complex in the right eye. The left eye appeared normal. Primary open-angle glaucoma was suspected, and the patient underwent a visual field examination on the same day. Perimetry showed that the mean deviations in the right and left eyes were −5.00 and −7.68 dB, respectively. A visual field defect in the inferior nasal aspect of the right eye corresponded to the retinal nerve fiber defect. However, right-sided homonymous hemianopia–like visual field defects were observed in both eyes. After the examination, the patient stated that a migraine attack had started 5 min before the examination and continued till after its end (attack duration was ∼20 min). In the follow-up examinations without migraine, homonymous hemianopia-like visual field defects disappeared, and only a glaucomatous visual field defect in the right eye was observed. Hence, the initial visual field examination findings reflected the effects of a migraine attack alongside glaucoma. Detailed interviews with patients may be beneficial for understanding visual field findings and preventing their untimely examination.

Assessing migraine patients with multifocal pupillographic objective perimetry

Background

To establish the effects of stimulating intrinsically-photosensitive retinal ganglion cells (ipRGCs) on migraine severity, and to determine if migraine produces objectively-measured visual field defects.

Methods

A randomized, open labelled, crossover study tested migraineurs and normal controls using multifocal pupillographic objective perimetry (mfPOP) with 44 test-regions/eye. A slow blue protocol (BP) stimulated ipRGCs, and a fast yellow protocol (YP) stimulated luminance channels. Migraine diaries assessed migraine severity. Per-region responses were analyzed according to response amplitude and time-to-peak.

Results

Thirty-eight migraineurs (42.0 ± 16.5 years, 23 females) and 24 normal controls (39.2 ± 15.2 years, 14 females) were tested. The proportion of subjects developing a migraine did not differ after either protocol, either during the 1st day (odds ratio 1.0; 95% confidence interval 0.2–4.4, p = 0.48) or during the first 3 days after testing (odds ratio 0.8; 95% confidence interval 0.3–2.1, p = 0.68). Migraine days/week did not increase following testing with either protocol in comparison to the baseline week (1.4 ± 1.6 pre-testing (mean ± SD), 1.3 ± 1.4 post-BP, and 1.3 ± 1.2 post-YP; p = 0.96), neither did other measures of severity. Migraine occurring up to 2 weeks before testing significantly lowered amplitudes, − 0.64 ± 0.14 dB (mean ± SE), while triptan use increased amplitudes by 0.45 ± 0.10 dB, both at p < 0.001.

Conclusions

Stimulating ipRGCs did not affect migraine occurrence or severity. Pupillary response characteristics were influenced by the occurrence of a recent migraine attack and a history of triptan use.

The Psychophysical Assessment of Hierarchical Magno-, Parvo- and Konio-Cellular Visual Stream Dysregulations in Migraineurs

Introduction

Although conscious, image-forming illusions have been noted in migraine, few studies have specifically sought to collectively evaluate the role of all three parallel visual processing streams in the retinogeniculostriate pathway involved with image-forming vision and their implications in the development of migraine symptoms.

Methods

We psychophysically assessed the functionality of the inferred magnocellular (MC), parvocellular (PC), and koniocellular (KC) streams at different hierarchical loci across three clinical groups: individuals who experience migraine with aura (MA; n=13), experience migraine without aura (MWO; n=14), and Controls (n=15). Participants completed four experiments: Experiment 1 designed to assess retinal short-wavelength-sensitive (S-) cone sensitivities; Experiment 2 intended to measure postretinal temporal and spatiochromatic contrast sensitivities; Experiment 3 intended to assess postretinal spatiotemporal achromatic contrast sensitivities; and Experiment 4 designed to measure thalamocortical color discriminations along the three cone-excitation axes.

Results

S-cone deficits were revealed with greater retinal areas being affected in MA compared to MWO participants. Findings across the four experiments suggest a prominent retinal locus of dysfunction in MA (lesser in MWO) with potential feedforward compensations occurring within the KC visual stream.

Conclusion

Complex, integrative network compensations need to be factored in when considering the dysregulating influences of migraine along the visual pathway.

Clinical impact of migraine for the management of glaucoma patients

Migraine is a common and debilitating primary headache disorder that affects 10-15% of the general population, particularly people of working age. Migraine is relevant to providers of clinical eye-care because migraine attacks are associated with a range of visual sensory symptoms, and because of growing evidence that the results of standard tests of visual function necessary for the diagnosis and monitoring of glaucoma (visual fields, electrophysiology, ocular imaging) can be abnormal due to migraine. These abnormalities are measureable in-between migraine events (the interictal period), despite patients being asymptomatic and otherwise healthy. This picture is further complicated by epidemiological data that suggests an increased prevalence of migraine in patients with glaucoma, particularly in patients with normal tension glaucoma. We discuss how migraine, as a co-morbidity, can confound the results and interpretation of clinical tests that form part of contemporary glaucoma evaluation, and provide practical evidence-based recommendations for the clinical testing and management of patients with migraine who attend eye-care settings.

The effect of duration post-migraine on visual electrophysiology and visual field performance in people with migraine

Purpose:

In between migraine attacks, some people show visual field defects that are worse when measured closer to the end of a migraine event. In this cohort study, we consider whether electrophysiological responses correlate with visual field performance at different times post-migraine, and explore evidence for cortical versus retinal origin.

Methods:

Twenty-six non-headache controls and 17 people with migraine performed three types of perimetry (static, flicker and blue-on-yellow) to assess different aspects of visual function at two visits conducted at different durations post-migraine. On the same days, the pattern electroretinogram (PERG) and visual evoked response (PVER) were recorded.

Results:

Migraine participants showed persistent, interictal, localised visual field loss, with greater deficits at the visit nearer to migraine offset. Spatial patterns of visual field defect consistent with retinal and cortical dysfunction were identified. The PERG was normal, whereas the PVER abnormality found did not change with time post-migraine and did not correlate with abnormal visual field performance.

Conclusions:

Dysfunction on clinical tests of vision is common in between migraine attacks; however, the nature of the defect varies between individuals and can change with time. People with migraine show markers of both retinal and/or cortical dysfunction. Abnormal visual field sensitivity does not predict abnormality on electrophysiological testing.

Statistical guidelines for the analysis of data obtained from one or both eyes

PURPOSE

Measurements obtained from the right and left eye of a subject are often correlated whereas many statistical tests assume observations in a sample are independent. Hence, data collected from both eyes cannot be combined without taking this correlation into account. Current practice is reviewed with reference to articles published in three optometry journals, viz., Ophthalmic and Physiological Optics (OPO), Optometry and Vision Science (OVS), Clinical and Experimental Optometry (CEO) during the period 2009-2012.

RECENT FINDINGS

Of the 230 articles reviewed, 148/230 (64%) obtained data from one eye and 82/230 (36%) from both eyes. Of the 148 one-eye articles, the right eye, left eye, a randomly selected eye, the better eye, the worse or diseased eye, or the dominant eye were all used as selection criteria. Of the 82 two-eye articles, the analysis utilized data from: (1) one eye only rejecting data from the adjacent eye, (2) both eyes separately, (3) both eyes taking into account the correlation between eyes, or (4) both eyes using one eye as a treated or diseased eye, the other acting as a control. In a proportion of studies, data were combined from both eyes without correction.

SUMMARY

It is suggested that: (1) investigators should consider whether it is advantageous to collect data from both eyes, (2) if one eye is studied and both are eligible, then it should be chosen at random, and (3) two-eye data can be analysed incorporating eyes as a 'within subjects' factor.

Choice of analytic approach for eye-specific outcomes: one eye or two?

PURPOSE

To investigate the use of analytic approaches for eye-specific outcomes in ophthalmology publications.

DESIGN

A review of analytic approaches used in original research articles published in ophthalmology journals.

METHODS

All 161 research articles published in 5 ophthalmology journals in the first 2 months of 2008 were considered. Publications were categorized according to analytic approach: 1 eye selected, both eyes contribute, or per-individual outcome. Studies were considered suboptimal when criteria for eye selection were not provided or when measurements from both eyes were included without interocular correlation being considered. Visual impairment prevalence data were used to illustrate analytic approach choices.

RESULTS

Measurements from both eyes were included in 38% of the 112 studies that used statistical inferential techniques. In 31 (74%), there was no mention of possible correlation. Only 7% used statistical methods appropriate for correlated outcomes. In 35 studies (31%), measurements from 1 eye were selected; 31% of these did not provide selection criteria. In 67%, only univariate tests were used. A review of 47 articles published in 2011 produced similar findings. Characteristics of studies were not found to differ according whether the studies were suboptimal. Using a test appropriate for correlated outcomes resulted in a P value 3.5 times that obtained ignoring the correlation.

CONCLUSIONS

Between-eye correlation seems not to be assessed commonly in ophthalmology publications, although its knowledge aids the choice of analytic approach when eye-specific variables are of interest. Statistical methods appropriate for correlated ocular outcome data are not being applied widely.

Homonymous hemianopia detected by short wavelength automated perimetry in a patient with normal standard perimetry and MRI

PURPOSE

To report a case of homonymous hemianopia detected by short wavelength automated perimetry (SWAP) in a patient with normal standard automated perimetry (SAP) and magnetic resonance imaging (MRI) of the brain and orbits.

METHODS

A 61-year-old woman with a history of motor vehicle accident with head injury nearly 50 years before presentation was referred for further evaluation as a glaucoma suspect. Complete ophthalmic examination, corneal pachymetry, SAP, SWAP, retinal nerve fiber layer analysis by ocular coherence tomography, and brain and orbital MRI were done.

RESULTS

The patient had intraocular pressure (IOP) of 18-mm Hg and vertical cup-to-disc ratios of 0.8 in each eye. Superior neuroretinal rim pallor was detected in both optic discs on dilated optic nerve examination, and corresponding retinal nerve fiber layer thinning was detected with ocular coherence tomography. SAP indicated minimal nonspecific changes in the right eye, whereas the left eye had a normal visual field. SWAP revealed a left homonymous hemianopia. Neurologic examinations and MRI of the brain and orbits were found to be normal.

CONCLUSIONS

SWAP can detect subtle hemianopic field defects in patients with normal standard perimetry.

Visual metacontrast masking in migraine

Background: In visual metacontrast masking, the visibility of a brief target stimulus can be reduced substantially if it is preceded (forward masking) or followed (backward masking) by a non-overlapping mask. These effects have been attributed to inhibitory processes within the visual system. Two previous studies have used metacontrast masking to assess inhibitory function in migraine and control groups, however, each used different types of masking and obtained different results.

Subjects and Methods: Forward, backward and combined forward and backward masking were compared in migraine (15 with visual aura, 15 without) and control ( n = 15) groups. Baseline trials were also included (target only).

Results: For all types of masking, both migraine groups were more accurate than the control group. When performance for the masking trials was expressed relative to baseline, however, there were no significant group differences. Performance in certain conditions nevertheless correlated significantly with migraine frequency and with the recency of the last attack.

Conclusions: The inhibitory processes involved in the masking tasks employed in this study do not appear to be impaired in migraine. Their better overall performance may reflect a sensitivity difference, perhaps as a consequence of a heightened neuronal response, which varies with the migraine cycle.

Scanning laser polarimetry with variable corneal compensation in migraine patients

PURPOSE

 This study aimed to compare scanning laser polarimetry measurements of retinal nerve fibre layer (RNFL) thickness in eyes of migraine patients with those in eyes of age-matched, healthy subjects.

METHODS

 The study was designed as an observational, prospective, cross-sectional study. It included 57 eyes of 57 patients with migraine with or without aura according to the criteria of the International Headache Society and 44 eyes of 44 age-matched healthy controls. Scanning laser polarimetry images were obtained using a commercial GDx VCC system (Version 5.3.1; Laser Diagnostic Technologies, Inc.). At each sitting, three sets of GDx VCC measurements were acquired for each patient and used in the analysis. Image acquisition was performed in undilated eyes in all subjects.

RESULTS

 The mean ± standard deviation RNFL average thickness parameter in the migraine subjects was significantly lower than in the control group, at 50.4 ± 4.8 μm versus 54.7 ± 3.4 μm, respectively (p < 0.0001). However, there were no differences between migraine subjects and controls in mean RNFL thickness in superior and inferior areas. In the migraine group the mean migraine disability assessment (MIDAS) score was 34.3 ± 15.3 and the mean number of attacks per year was 17.1 ± 6.9 (range 6-28). The mean RNFL average thickness parameter was significantly correlated with MIDAS score (r = - 0.86, p < 0.0001) and frequency of attacks (r = - 0.86, p < 0.0001).

CONCLUSIONS

The mean RNFL average thickness parameter was found to be thinner in migraine patients. In addition, we found a strong correlation between migraine severity and RNFL average thickness parameters.

[Functional glaucoma diagnosis]

Achromatic perimetry is the gold standard in glaucoma diagnosis for detecting functional defects from glaucomatous optic neuropathy. Because achromatic perimetry is only able to detect scotomas after loss of up to 30-40% of retinal ganglion cells, early diagnosis using this method is rarely possible. Therefore, a lot of new perimetric procedures have been developed in recent years to detect new scotomas at a very early stage. This review summarizes the theoretical background of retinal ganglion cells in order to better understand the theoretical approaches of new perimetric methods. In addition, the most important commercial perimetric devices currently available are presented.

Assessment of spatial–contrast function and short-wavelength sensitivity deficits in patients with migraine

AIMS

To study spatial-contrast function and short-wavelength sensitivity deficits in a migraine population with a disease duration of 30 years or less.

MATERIALS AND METHODS

In this prospective, cross-sectional study, we evaluated 28 subjects with migraine headache and 15 nonheadache healthy controls. Visual fields were evaluated using the Humphrey Field Analyzer 750i and the 30-2, blue and yellow threshold programme. Contrast sensitivity (CS) was measured at 1.5, 3, 6, 12, and 18 cpd spatial frequencies, using the Functional Acuity Contrast Test (F.A.C.T.). The results of the visual field parameters (mean defect (MD) and pattern standard defect (PSD)) and CS were compared with 15 age-equivalent normal subjects.

RESULTS

Short-wavelength amplitude perimetry (SWAP) parameters and CS scores at all spatial frequencies were significantly altered in the migraine patients when compared with the control subjects. Visual field parameters correlated significantly with contrast sensitivity scores: positively for MD (r=0.39, P=0.01; r=0.43, P=0.005; r=0.56, P=0.0001; r=0.45, P=0.003; r=0.48, P=0.0001) and negatively for PSD (r=-0.45, P=0.003; r=-0.45, P=0.003; r=-0.51, P=0.001; r=-0.53, P=0.0001; and r=-0.67, P=0.0001) at all (1.5, 3, 6,12, and 18 cpd) spatial frequencies, respectively. Migraine duration correlated negatively with MD (r=-0.42, P=0.04) and positively with PSD (r=0.42, P=0.03).

CONCLUSION

Migraineurs had significantly altered visual field and contrast function at all spatial frequencies to the normal population. These defects share some features with early stages of glaucoma and may relate a possibility for a common vascular disease pathogenesis in these two conditions.