Standard Perimetry Research Articles

The electrophysiological tests in the early detection of the visual pathway dysfunction in patients with microadenoma

PurposeTo evaluate the validity of electrophysiological tests in the early diagnosis of a ganglion cells and/or optic nerve dysfunction in patients with pituitary microadenoma.Methods66 eyes, from 33 patients with microadenoma with no evidence of the optic chiasm compression in magnetic resonance imaging (MRI) and the visual impairment in the routine ophthalmological examination, standard static perimetry (24-2 white on white) and optical coherence tomography (HD-OCT), were analysed. The pattern electroretinogram (PERG), standard pattern visual evoked potentials (PVEPs) and multichannel visual evoked potentials (mVEPs) (ISCEV standards) were performed. The results obtained from the electrophysiological tests were compared to the same number of age-matched healthy controls.ResultsStatistically significant differences between the patients with microadenoma and healthy controls were detected in all electrophysiological tests (p < 0.001). The most frequent abnormalities were observed in mVEPs (25/33 patients, 75.8%; 43/66 eyes, 65.2%). The most frequent features registered in this test were: (1°4′)—an increase in the P100wave latency from uncrossed fibres (13/33 patients, 39.39%; 21/66 eyes, 31.8%) and (0°16′)—an amplitude reduction of this wave from the crossed fibres (11/33 patients, 33.33%; 19/66 eyes, 28.8%). The changes in PVEPs (15/33 patients, 45.5%; 25/66 eyes, 37.9%) and PERG (10/33 patients, 30.3%; 15/66 eyes, 22.7%) were also registered. Of all the tests and parameters analysed in the study, the greatest diagnostic value in detecting the visual pathway dysfunction in this group of patients was the amplitude of P100 wave from the crossed fibres of the mVEPs (1°4′) with a sensitivity of 60.6% and a specificity of 93.8%. These parameters suggest that this type of dysfunction is downstream to the chiasm and can also indicate the visual pathway dysfunction severity.ConclusionsIn patients with microadenoma, the abnormalities in the electrophysiological tests are registered even without clinical evidence of visual impairment from the routine ophthalmological examination, SAP, OCT and chiasmal compression in MRI. The mVEPs have the most significant role in the diagnosis of the visual pathway dysfunction in patients with microadenoma.

Determinants of Test Variability in Scotopic Microperimetry: Effects of Dark Adaptation and Test Indices.

PurposeTo test the effect of different dark adaptation conditions and reliability indices on the variability of two color scotopic microperimetry.MethodsWe analyzed data from 22 consecutive visually healthy adults. Scotopic microperimetry was performed (Macular Integrity Assessment microperimeter, CenterVue, Padua, Italy) with two wavelength stimuli, cyan (505 nm) and red (627 nm), after a dark adaptation time of 10, 20, or 30 minutes. All tests were repeated twice to measure test–retest variability with Bland–Altman plots. We also provide a method to more accurately quantify the false-positive (FP) responses based on response data (button pressing) from the device, similar to FP responses used in standard static perimetry. Data on fixation stability (95% bivariate contour ellipse area) and blind spot responses were also extracted. Their relationship with measured sensitivity (in decibels) and test–retest variability was quantified through linear mixed effect models.ResultsDark adaptation had a significant effect on the sensitivity (dB) measured with the cyan stimulus (P < 0.001), but no effect on the red stimulus. Of the three metrics, the novel FP responses showed the best association with test–retest variability and was the only predictor consistently significant for all tests (P < 0.01).ConclusionsDark adaptation protocols should be carefully standardized for scotopic testing, especially if a cyan stimulus is used. The proposed FP responses should be used to assess reliability of microperimetry examinations instead of other metrics.Translational RelevanceWe developed a method to calculate a more accurate estimate of the FP responses using data available to all researchers, generalizable to all Macular Integrity Assessment microperimeter tests.

The Relationship Between Macula Retinal Ganglion Cell Density and Visual Function in the Nonhuman Primate.

PurposeLoss of ganglion cell inner plexiform layer (GCIPL) and visual sensitivity in the macula region are known to occur at all stages of glaucoma. While both are dependent on the underlying retinal ganglion cells (RGCs), the relationship between structure and function is modest. We hypothesize that the imprecise relationship is due to a lack of direct correspondence between in vivo measures and RGC counts, as well as the relatively large stimulus size used by standard perimetry, which exceeds spatial summation.MethodsThe relationship between optical coherence tomography (OCT)–derived GCIPL thickness and corresponding inner cell density from retinal flat mounts was determined for four nonhuman primates with varying stages of neuropathy. Normative data for 10-2 threshold using Goldman size I to V stimuli were established for 10 animals, 4 of which were then followed longitudinally with OCT and perimetry. The relationship between GCIPL volume, which incorporated stimulus size after removal of residual thickness, and differential light sensitivity was determined for both experimental glaucoma and healthy eyes.ResultsPeak inner retinal cell density was 63,052 ± 9238 cells/mm2 in the healthy eye. Cell density was related to both GCIPL thickness and eccentricity (R2 = 0.74, P < .01). For all 10-2 eccentricities, size III stimuli were greater than the critical area (P < 0.01). Based on the structural and histologic relationship, the critical area corresponds to approximately 156 RGCs.ConclusionsThe relationship between cell density and GCIPL thickness is dependent on retinal eccentricity. For 10-2 perimetry, perimetric loss, especially at earlier stages of neuropathy, may best be detected using size II or smaller stimuli.

Static automated perimetry in the diagnosis of glaucoma. Part 1: Basic principles

Static automated perimetry is an indispensable tool in the diagnosis of glaucoma. It is used to study the differential light sensitivity of the retina in different points of the visual field. The most important is the central zone of the visual field, many perimetric programs and strategies have been developed for its examination. Using standard background brightness, we can vary sizes, location methods and the type of stimulus delivery. The proper use of standard achromatic perimetry is crucial for the correct management of glaucoma patients. This review analyzes literature on the basic principles of static perimetry in the examination of differential photosensitivity of the retina.

Effect of retinal protective therapy on optical coherence tomography angiography (pilot study)

To assess the influence of the frequency of retinal protective therapy courses on the indicators of regional hemodynamics of the eye. The study included 17 patients (34 eyes) with a diagnosis of primary open-angle glaucoma (POAG), advanced stage. The patients were divided into 2 groups: the first group received a course of retinal protective therapy with Retinalamin every 3 months, the second group received a course of retinal protective therapy with Retinalamin every 6 months. All patients underwent standard ophthalmological examination including standard automatic perimetry according to the 24-2 program, optical coherence tomography angiography (OCT-A) of the macular area and optic disc. The comparison of hemodynamic parameters of all vascular plexuses of the retina at the beginning and at the end of the study, as well as intergroup comparison did not reveal any statistically significant differences (p>0.05). However, when studying the density and fractal dimension of the vascular bed, multidirectional trends were observed. Specifically, in the peripapillary region, there was a decrease in the length from 19.8 (1/mm) to 19.0 (1/mm) (p=0.37) and the density from 36.6% to 35.7% (p=0.63) of the vascular bed of the peripapillary capillary plexus of the retina in patients of the first group. In the superficial vascular plexus, the trend in the density of the vascular bed in both groups slightly changed (in group 1 - 38.1% and 38.3%, p=0.97; group 2 - 37.8% and 38.7%, p=0.46). The fractal dimension of the vascular bed in the first group tended to increase during treatment from 18.8 (1/mm) to 19.1 (1/mm) (p=0.5), while in the second group, on the contrary, it had tendency to decrease from 18.6 (1/mm) to 17.9 (1/mm) (p=0.63). In the deep vascular plexus, the density of the vascular bed trended to decrease in both groups, but in group 2 (42.5% and 42.4%, p=1.0) it was more pronounced than in the first group (42.5% and 42.6%, p=0.82). However, the fractal dimension of the vascular bed increased in group 1 (21.0 (1/mm) and 21.3 (1/mm), p=0.43) and showed a slight tendency to decrease in group 2 (21.5 (1/mm) and 21.0 (1/mm), p=0.86). The general trend of changes in hemodynamic parameters demonstrates a potential positive effect, especially in the data related to the deep vascular plexus.

Outcome of a single XEN microstent implant for glaucoma patients with different types of glaucoma

BackgroundThe aim of this retrospective study was to compare the efficacy and safety profile of a single XEN-microstent in different types of primary and secondary open angle glaucoma.MethodsA single XEN microstent was implanted in patients with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), pseudoexfoliation glaucoma (PEX) and secondary glaucoma (Sec.Gl). The intraocular pressure (IOP), the active substances of the applied IOP-lowering drugs, the best corrected visual acuity (BCVA) and the mean deviation (MD) of the perimetry were measured at baseline and at regular follow-ups, scheduled at 2 days and 1, 3, 6 and 12 months after surgery.Results153 eyes were included in this analysis. 113 eyes were affected by POAG (74%), 5 eyes by NTG (3%), 22 eyes by PEX (14%) and 13 eyes by Sec. Gl (9%). Mean IOP decreased in all treatment groups during the 12 months of follow-up (complete group: 23.9 ± 7.4 to 15.4 ± 5.1 mmHg (p < 0.01); POAG: 22.8 ± 6.5 to 15.1 ± 4.6 mmHg (p < 0.01); NTG: 16.6 ± 3.4 to 11.6 ± 2.2 mmHg (p < 0.05); PEX: 28.0 ± 7.9 to 17.1 ± 6.6 mmHg (p < 0.01); Sec.Gl: 28.9 ± 13.9 to 15.5 ± 6.9 mmHg (p < 0.05)). In the 153 eyes the average number of IOP-lowering drugs applied decreased from 2.6 ± 1.2 to 0.8 ± 1.3 12 months after surgery (p < 0.01). BCVA and mean deviation of automated standard perimetry remained stable in all groups during follow-up.ConclusionAs in eyes suffering from POAG, IOP and number of IOP-lowering drugs applied can be effectively reduced by XEN implantation in eyes suffering from NTG, PEX and secondary glaucoma while leaving BCVA and visual field unchanged.Trial registrationTrial was registered at DRKS (registration number: DRKS00020800, Registered 25.February 2020 - Retrospectively registered).

Structural and Functional Disorders in Glaucoma: the Prospects for Preclinical Diagnosis. Part 1. Is the Search for what Comes First Relevant?

The review analyzes the capabilities of modern technologies of structural neuroimaging of the retina, standard perimetry, and studies of ocular blood flow in the early diagnosis and management of glaucoma. The relevance of the search for those structural and functional changes that are primary in the development of glaucomatous optical neuropathy (GON) and the diagnostic method that has the greatest clinical significance is discussed. Progress in understanding the pathogenesis of glaucoma and the expansion of scientific understanding of key risk factors for the development and progression of the disease, including genetic factors, can be crucially important to substantiate new strategies for preclinical diagnosis and the development of radically new approaches to personalized and preventive glaucoma therapy. However, the search for what arises most early with in primary open-angle glaucoma — changes in structure or function — will not have clinical relevance unless you take into account the capabilities of specific methods of structural and functional neuroimaging that represent information at various levels of organization of the visual system. The search for a single primary factor in the pathogenesis of GON can lead to an erroneous exaggeration of the close relationship between the variables being studied, which in reality either does not exist as a causal relationship or is significantly less than what is supposed — the phenomenon called “illusory correlation”. The reliable diagnosis of early changes that occur before the clinical manifestation of glaucoma is most likely to be based on a combination of structural, functional, and hemodynamic indicators, aimed not only to increase the sensitivity of diagnosis in detecting the earliest events in the development of GON, but rather to dramatically improve the understanding and quality of interpretation of those markers that we own.

Utility of the Modified Isolated-check Visual Evoked Potential Technique in Functional Glaucoma Assessment.

PRE[COMBINING ACUTE ACCENT]CIS:: Cortical response to low-contrast stimuli, as measured by isolated-check visual evoked potential (icVEP) technology, has the potential to provide functional assessment that may complement standard achromatic perimetry in assessing glaucomatous change. PURPOSE To evaluate the utility of modified icVEP testing in detecting functional glaucomatous damage. MATERIALS AND METHODS Subjects who met predetermined criteria of controls, glaucoma suspects, preperimetric glaucoma, or glaucoma were enrolled in this prospective cross-sectional study from a single tertiary care center. Glaucoma patients were further categorized as early, moderate, advanced, or severe on the basis of Hodapp-Anderson-Parrish criteria. icVEP testing was performed with ten 2-second runs per qualified eye using the EvokeDx testing software. Multivariate statistics were used to calculate signal-to-noise ratios (SNR) and perform outlier analysis. RESULTS In total, 140 eyes met criteria (mean±SD; age of 63±14 y; 49% male; logMAR visual acuity, 0.11±0.089). There was no significant difference in age, sex, or logMAR visual acuity among the groups. Controls had a significantly higher SNR than all other groups (P<0.003), including patients with preperimetric glaucoma. Among those with glaucoma, the early glaucoma patients had significantly higher SNR than the moderate, advanced, or severe glaucoma cohorts (P<0.04). The optimal SNR cutoff for differentiating between glaucomatous and nonglaucomatous eyes was 0.95, both with (sensitivity 82%, specificity 76%) and without (sensitivity 82%, specificity 100%) glaucoma suspects included in analysis. CONCLUSIONS icVEP technology has the potential to complement standard achromatic perimetry in functional assessment of glaucomatous defects.

Laminar and Prelaminar Tissue Characteristics of Glaucomatous Eyes Using Enhanced Depth Imaging OCT

To investigate characteristics of the lamina cribrosa (LC) and prelaminar tissue (PLT) in eyes of patients with primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG), and pseudoexfoliation glaucoma (PXG) using enhanced depth imaging (EDI) OCT. Observational case-control study. A total of 116 eyes from 116 participants with POAG (n= 30 eyes), PACG (n= 29 eyes), or PXG (n= 29 eyes) and 28 healthy eyes. Participants underwent a complete ophthalmologic examination in addition to corneal pachymetry, standard achromatic perimetry, peripapillary retinal nerve fiber layer (RNFL) OCT, and EDI OCT, as well as measurement of LC, PLT thickness, and LC depth. Lamina cribrosa measurement, PLT thickness, and LC thickness. Average LC thickness was significantly different among the 4 groups with the thinnest values in the PXG group. Prelaminar tissue also was significantly thinner in PXG eyes. The POAG eyes demonstrated the largest LC depths (P < 0.05), whereas PACG and healthy eyes demonstrated the smallest LC depths (P < 0.05). Mean deviation on standard achromatic perimetry and average thickness on peripapillary RNFL OCT were associated significantly with LC and PLT thickness. Pseudoexfoliation glaucoma eyes demonstrate reduced LC and PLT thickness compared with POAG, PACG, and healthy eyes. Lamina cribrosa depth was larger in POAG eyes as compared with PXG, PACG, and healthy eyes. These findings may account for the peculiar appearance of the optic nerve head in PXG eyes.

Lessons Learned from 23 Years of Experience in Testing Visual Fields of Neurologically Impaired Children

ABSTRACT We sought to investigate the reliability of standard conventional perimetry (SCP) in neurologically impaired (NI) children using the examiner-based assessment of reliability scoring system and to determine the difference in time to diagnosis of a visual field defect between SCP and a behavioural visual field (BVF) test. Patient records of 115 NI children were retrospectively analysed. The full field peritest (FFP) had best reliability with 44% ‘good’ scores versus 22% for Goldmann perimetry (p < .001). The mean age of NI children able to perform SCP was 8.3 years versus 4.6 years for the BVF test (p < .001). Use of the BVF test may significantly reduce time to diagnosis.

Correlation of retinal sensitivity in microperimetry with vascular density in optical coherence tomography angiography in primary open-angle glaucoma.

PurposeTo evaluate the correlation between retinal sensitivity in microperimetry (MP) with vessel density (VD) using optical coherence tomography angiography (OCTA) in primary open-angle glaucoma (POAG).MethodsWe enrolled 30 participants (52 eyes) with POAG and 15 participants (23 eyes) in the healthy control group. All participants were examined for retinal structure using OCTA to assess VD and Spectral domain OCT (SD-OCT) to assess ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (pRNFL) thickness. Retinal sensitivity was tested with MP and standard automatic perimetry (SAP).ResultsThe VD in moderate/severe POAG was lower than that in mild POAG and healthy control in the macular superficial vascular plexus (SVP) (38.7±6.3% vs. 42.9±5.2%, 49.7±2.6% respectively, P<0.001) and peripapillary radial peripapillary capillaries (pRPC) (36.4±5.7% vs. 43.6±6.6%, 49.1±2.4% respectively, P<0.001). The Pearson’s correlations between function-structure parameters were strongest with MP average sensitivity threshold and SVP VD in the area of whole macula (r = 0.68); followed by SAP mean deviation (MD) and pRNFL thickness (r = 0.63); SAP MD and pRPC VD (r = 0.59) and MP average threshold and GCC thickness (r = 0.54). We found the AUROCs for discriminating between glaucomatous and healthy eyes were highest for structural parameters as follows: pRNFL (0.94), macular SVP whole (0.92), pRPC (0.92) and GCC (0.91). Pairwise comparison of the above parameters showed no difference (P>0.05).ConclusionThe relationship between microvascular damage in the macular SVP whole and the decrease of MP average sensitivity threshold is stronger than the pRNFL thickness measurements and SAP parameters. OCTA and MP techniques are valuable methods that allow clinically monitor structural and functional changes in glaucomatous eyes.

Diagnostic Possibilities of Standard Automatic and FunctionSpecific Perimetry (HFA, Octopus) in the Study of the Visual Field in Patients with Compression in the Chiasm-Sellar Region

The literature review presents the results of a static perimetry for the study of the visual field in patients with compression in the chiasm-sellar region on the Humphrey Visual Field Analyzer (HFA) and Octopus. These models of perimeters are recognized as the “gold standard” and are most widely used in the global ophthalmic practice. The analysis of research results using traditional and function-specific perimetry with selective stimulation of the magnocellular and koniocellular (frequency-doubling technology perimetry, FDT; short-wavelength automated perimetry, SWAP) visual pathways was performed. The literature data analysis allows us to conclude that the static perimetry for the study of the visual field in patients with chiasmatic compression is carried out quite widely and is informative. But despite this, there are no generally accepted recommendations on the use of certain testing strategies and programs for the diagnosis and further dynamic observation of changes in the visual field in patients with this pathology. In this regard, it is advisable to conduct further studies that will allow the formation of standard perimetric protocols for diagnosing and monitoring visual field defects in patients with compression in the chiasm-sellar region based on a comparative analysis of the diagnostic informativity of various strategies and programs.

Utility of the Modified Isolated-check Visual Evoked Potential Technique in Functional Glaucoma Assessment.

To evaluate the utility of modified icVEP testing in detecting functional glaucomatous damage. Subjects who met predetermined criteria of controls, glaucoma suspects, preperimetric glaucoma, or glaucoma were enrolled in this prospective cross-sectional study from a single tertiary care center. Glaucoma patients were further categorized as early, moderate, advanced, or severe on the basis of Hodapp-Anderson-Parrish criteria. icVEP testing was performed with ten 2-second runs per qualified eye using the EvokeDx testing software. Multivariate statistics were used to calculate signal-to-noise ratios (SNR) and perform outlier analysis. In total, 140 eyes met criteria (mean±SD; age of 63±14 y; 49% male; logMAR visual acuity, 0.11±0.089). There was no significant difference in age, sex, or logMAR visual acuity among the groups. Controls had a significantly higher SNR than all other groups (P<0.003), including patients with preperimetric glaucoma. Among those with glaucoma, the early glaucoma patients had significantly higher SNR than the moderate, advanced, or severe glaucoma cohorts (P<0.04). The optimal SNR cutoff for differentiating between glaucomatous and nonglaucomatous eyes was 0.95, both with (sensitivity 82%, specificity 76%) and without (sensitivity 82%, specificity 100%) glaucoma suspects included in analysis. icVEP technology has the potential to complement standard achromatic perimetry in functional assessment of glaucomatous defects.

Validation of a Head-mounted Virtual Reality Visual Field Screening Device.

Testing the visual field is a vital sign for diagnosing and managing glaucoma. The current gold standard, the Humphrey visual field analyzer (HFA), is large, expensive and can be uncomfortable for some patients. The current study investigated the CFA, a virtual reality head-mounted visual field testing device, as a possible subjective field test for glaucoma screening and eventually glaucoma monitoring. The CFA presented stimuli in the same 54 positions as the HFA 24-2 SITA Standard test using a suprathreshold algorithm approximating an 18 dB deficit. A total of 157 patients (both controls and glaucoma patients) at the Aravind Eye Hospital, Pondicherry, India, were tested with both devices. The number of stimuli missed on the CFA correlated with HFA mean deviation (r=0.62, P<0.001), and with pattern standard deviation (r=0.36, P<0.001). The area under the receiving operator characteristic curve was 0.77±0.06 for mild glaucoma (HFA mean deviation ≥-6 dB) and 0.86±0.04 for moderate-advanced glaucoma (HFA mean deviation <-6 dB). Patients with an 18 dB or worse deficit at a point in the visual field on the HFA failed to see the CFA stimulus at the same position 38% of the time. While the CFA did not reliably identify deficits that matched the HFA, it was moderately effective at identifying glaucoma subjects. Further refinements to the device will be required to improve point by point testing performance and screening performance.

Comparison of Short- And Long-Term Variability in Standard Perimetry and Spectral Domain Optical Coherence Tomography in Glaucoma

To assess short- and long-term variability on standard automated perimetry (SAP) and spectral domain optical coherence tomography (SD-OCT) in glaucoma. Prospective cohort. Ordinary least squares linear regression of SAP mean deviation (MD) and SD-OCT global retinal nerve fiber layer (RNFL) thickness were fitted over time for sequential tests conducted within 5weeks (short-term testing) and annually (long-term testing). Residuals were obtained by subtracting the predicted and observed values, and each patient's standard deviation (SD) of the residuals was used as a measure of variability. Wilcoxon signed-rank test was performed to test the hypothesis of equality between short- and long-term variability. A total of 43 eyes of 43 glaucoma subjects were included. Subjects had a mean 4.5 ± 0.8 SAP and OCT tests for short-term variability assessment. For long-term variability, the same number of tests were performed and results annually collected over an average of 4.0 ± 0.8 years. The average SD of the residuals was significantly higher in the long-term than in the short-term period for both tests: 1.05 ± 0.70 dB vs. 0.61 ± 0.34 dB, respectively (P < 0.001) for SAP MD and 1.95 ± 1.86μm vs. 0.81 ± 0.56μm, respectively (P < 0.001) for SD-OCT RNFL thickness. Long-term variability was higher than short-term variability on SD-OCT and SAP. Because current event-based algorithms for detection of glaucoma progression on SAP and SD-OCT have relied on short-term variability data to establish their normative databases, these algorithms may be underestimating the variability in the long-term and thus may overestimate progression over time.

Fractal Phototherapy in Neuroprotection of Glaucoma

Purpose: to study the effect of low-intensity fractal light stimulation on the sensitivity in the visual field in patients with suspected glaucoma (SG) and primary open-angle glaucoma (POAG). Material and Methods. The study involved 146 people, including 98 patients of the main group (No. 1) and 49 people from the control group “placebo”-therapy (No. 2). Standard automatic perimetry was performed (SITA-Standard, Humphrey, CarlZeissMeditec, 24-2). The dynamics of the perimetry indices MD and PSD were evaluated before and after the course of a ten 10-minute session of fractal phototherapy or after a 10-day course of relaxation consisting in watching a particular training video twice a day. The maximum brightness of the flashes on the cornea during phototherapy was 10–12 lux, the fractal dimension of the optical signal was D = 1.4. Results. A two-week course of low-intensity stimulation with fractal optical signals reliably improved the MD reflected the common defect in the visual field, in all patients with SG and POAG. The expositions to videos with a relaxation program did not have a statistically significant effect on MD and PSD indices. The pronounced effect of fractal stimulation revealed in eyes with POAG III (a reduction of MD on average by 4.39 dB) suggests that even in advanced stages of glaucoma in the general population of retinal ganglion cells there is a significant percentage of cells that are still at the plastic stage of reversible functional changes and can respond positively to therapy. The results substantiate the feasibility of application neuroprotective therapy to patients with any stage of glaucoma, including the advanced stage. Conclusion. In this study, we first used the technology of fractal optical stimulation for the treatment of glaucoma. The first evidence of the neuroprotective effect of fractal phototherapy for POAG at different stages has been obtained. Fractal stimulation can be considered as a new non-pharmacological (physiotherapeutic) approach to neuroprotective therapy, whose potential and mechanisms need to be studied in future studies.

This Issue of Acta

This Issue of Acta

Contributions of the Melanopsin-Expressing Ganglion Cells, Cones, and Rods to the Pupillary Light Response in Obstructive Sleep Apnea.

To investigate the impact of obstructive sleep apnea (OSA) on the contribution of inner and outer retinal photoreceptors to the pupillary light response (PLR). Ninety-three eyes from 27 patients with OSA and 25 healthy controls were tested. OSA severity was graded according to the apnea-hypopnea index. PLR was measured monocularly with an eye tracker in a Ganzfeld in response to 1-second blue (470 nm) and red (640 nm) flashes at -3, -2, -1, 0, 1, 2, and 2.4 log cd/m2. Peak pupil constriction amplitude, peak latency, and the postillumination pupil response were measured. The Cambridge Colour Test, standard automatic perimetry, spectral domain optical coherence tomography, polysomnography, and the Pittsburgh Sleep Quality Index were used. OSA patients have a significantly decreased peak pupil constriction amplitude for blue stimuli at -3, -2, -1, 1 log cd/m2 and at all red flash luminances (P < 0.050), revealing reduction of outer retina contributions to PLR. OSA patients showed reduced peak latency for blue (-2, 0, 2, 2.4 log cd/m2) and red stimuli (-2, 0 log cd/m2; P < 0.040). No significant difference was found in the melanopsin-mediated PLR. This study is the first to evaluate the inner and outer retinal contributions to PLR in OSA patients. The results showed that the outer retinal photoreceptor contributions to PLR were affected in moderate and severe OSA patients. In contrast, the inner retina contributions to PLR are preserved.

Visual Field Mean Deviation at Diagnosis of Idiopathic Intracranial Hypertension Predicts Visual Outcome.

A robust predictor of visual outcome in idiopathic intracranial hypertension (IIH) would be useful in management, but there is limited information on this point. The purpose of this study was to ascertain whether visual field mean deviation on standard static perimetry performed at diagnosis in a large patient cohort is a reliable predictor of visual outcome. We retrospectively reviewed the automated visual field mean deviations at diagnosis and at final encounter in 79 patients with IIH examined in the neuro-ophthalmology clinics at a single academic medical center from 1999 to 2015. Of the 79 study patients, 66 (84%) entered with visual field mean deviations of -7 dB or better. Of those 66 patients, 59 (89%) had final mean deviations of -4 dB or better and 33 (56%) had final mean deviations of -2 dB or better. The single patient who had an initial mean deviation of -7 dB or better and a poor final mean deviation (-32 dB) was nonadherent to prescribed medication. Of the 13 (21%) patients who entered with mean deviations worse than -7 dB, 11 (85%) ended up with poor visual outcomes, their final mean deviations ranging from -5 dB to -32 dB. Over half of those 13 patients had required surgery for IIH, often within 3 weeks of diagnosis, owing to severe papilledema and visual dysfunction at the time of diagnosis. Based on this retrospective study, patients with IIH who have relatively mild visual dysfunction at diagnosis are likely to have a favorable visual outcome, provided they are adherent to recommended treatment. Many of those with poor visual function at diagnosis will have unfavorable visual outcomes despite aggressive treatment.

Localization of Neuronal Gain Control in the Pupillary Response.

Multifocal pupillographic objective perimetry (mfPOP) is being developed as an alternative to standard visual perimetry. In mfPOP, pupil responses to sparse multifocal luminance stimuli are extracted from the overall composite response. These individual test-region responses are subject to gain-control which is dependent on the temporal and spatial density of stimuli. This study aimed to localize this gain within the pupil pathway. Pupil constriction amplitudes of 8 subjects (41.5 ±12.7 y, 4 male) were measured using a series of 14 mfPOP stimulus variants. The temporal density of stimulus signal at the levels of retina, pretectal olivary nuclei (PON), and Edinger-Westphal nuclei (EWN) were controlled using a combination of manipulation of the mean interval between stimulus presentations (3 or 6 stimuli/s/hemiretina) and the restriction of stimuli to specific subsets of the 24 visual field test-regions per eye (left or right eye, left or right hemifield, or nasal or temporal hemifield). No significant difference was observed between mfPOP variants with differing signal density at the retina or PON but matched density at the other levels. In contrast, where signal density differed at the EWN but was the same at the retinal and PON levels e.g., between 3 stim/s homonymous hemifield and all test-region variants, significant reductions in constriction amplitudes were observed [t(30) = −2.07 to −2.50, all p < 0.05]. Similar, although more variable, relationships were seen using nasal, and temporal hemifield stimuli. Results suggest that the majority of gain-control in the subcortical pupillary pathway occurs at the level of the EWN.