Hue discrimination in jewellery appraisers exceeds normal performance.

PURPOSE: The FM-100 Hue test is used for vocational purposes where hue discrimination is of the upmost importance, such as in jewellery appraisals where small errors in hue discrimination can lead to significant differences in gemstone valuation. The purpose of this study was to determine if the cone contrast test (CCT) could predict performance on the FM-100 Hue, providing a potential alternative test for screening of jewellery appraisers. METHODS: Members of the National Association of Jewelry Appraisers (NAJA; n = 18, ages 34 to 76 years) requiring colour vision certification with the FM-100 Hue were invited to participate in a study to assess performance on the Ishihara test, FM-100 Hue, Lanthony Desaturated D-15 and the CCT. The FM-100 Hue test was administered to award or renew NAJA certification, while the CCT was included as a possible alternative certification test. RESULTS: Average CCT M and S cone scores were predictive of FM-100 Hue total error score (TES: F1,16  = 7.77, p < 0.02; r2  = 0.33). The regression equation indicates that a CCT score of <60 is 3SD below the mean TES in our cohort of jewellery appraisers. Seventeen of 18 jewellery appraisers had FM-100 Hue TES scores significantly below the lower limit for age-matched normal values, indicating exceptional performance (p < 0.001). CONCLUSIONS: Results indicate the CCT may be an effective substitute for the FM-100 Hue to provide certification of jewellery appraisers, but the small sample size warrants additional comparative validation to support sole utilisation of the CCT. It is of interest that this sample of jewellery appraisers showed lower (i.e., better) than normal TES scores despite mitigating senescence factors. It is conceivable that the enhanced jewellery appraisers' hue discrimination reflects perceptual learning, wherein reward-based repetition on specific tasks can improve performance, even in adulthood beyond critical periods.

Measurement of dark adaptometry during ISCEV standard flash electroretinography.

PURPOSE: Dark adaptometry (DA) is a sensitive test for diagnosis of retinal disease. Patients requiring flash electroretinograms (ERGs) benefit from DA for proper diagnosis. Our purpose was to develop a DA test to be administered during the 20-min dark adaptation period of the flash ERG ( www.iscev.org ) using alternating red and blue stimuli to bias responses in favor of cones (red) and rods (blue). METHODS: An ERG Ganzfeld was used to measure DA in 21 normal subjects and 21 patients with retinal disease. Subjects underwent 75 s of preadaptation followed by 20 min of DA using an adaptive staircase to detect alternating flashes of red and blue light. Normative red and blue DA was compared to patients at the 10-min midpoint and 20-min final threshold. RESULTS: At 15 min, normals and patients showed asymptotic plateaus; hence, final thresholds were achieved within 15 min for parameters of this study. In RP and allied conditions (n = 11), 100% showed significantly elevated blue DA thresholds (> 2SD above normal) at 10 and 20 min. In cone diseases, 80% showed abnormal red DA at 10 min and 30% at 20 min, indicating that delayed adaptation is more typical of cone disease. CONCLUSIONS: Two-color DA is expediently measured during the DA phase of ERGs providing clinical data which separate rod and cone dysfunction critical for accurate diagnosis of various retinal diseases. It provides an additional benchmark for monitoring function over time and invaluable guidance for patients functioning in dimly lit settings.

A Comparison Between Three Computer-Based Cone Specific Color Vision Tests.

INTRODUCTION: Computerized color contrast sensitivity (CS) tests that aim to determine presence, type, and severity of color vision deficiency have been developed and are available, but data on agreement between tests is lacking. The purpose of the present study was to determine data agreement between three computerized color vision tests.METHODS: A total of 50 subjects, 25 color vision normal (CVN) and 25 color vision deficient (CVD), were tested with the Konan CCT-HD®, NCI, and a modified version of the Innova CCT. Sensitivity and specificity were compared across systems as well as differences in log CS values and how these relate to standards used to classify occupational performance.RESULTS: Each test showed 100% sensitivity for detection of hereditary red-green CVDs as well as type (protan vs. deutan). Each test showed 100% specificity for confirming normal red-green color vision in CVNs. Innova CCT and NCI showed 100% specificity in CVNs and CVDs for S cone CS. Konan CCT-HD® showed 96% specificity in CVNs and 92% in CVDs for S cone CS.DISCUSSION: These findings indicate that each test reliably identifies hereditary CVD and confirms normal color vision. However, the three tests differ slightly in log CS values used to determine pass/fail scores of red-green color vision using a 100-point scale, and all show that protans consistently score lower than deutans on cone CS. Hence, depending on the criterion used in occupational settings, a single score may not prove equitable for individuals who have a protan deficiency.Lovell J, Rabin J. A comparison between three computer-based cone specific color vision tests. Aerosp Med Hum Perform. 2023; 94(2):54-58.

A new method to quantify the human visual threshold from melanopsin sensitive ganglion cells.

Traditional photoreceptors utilize the chromophore retinal to absorb light coupled with a unique opsin protein to specify receptor spectral sensitivity. Light absorption triggers a cascade of events transducing light energy to neural signals beginning with graded potentials in receptors (rods and cones) and bipolar cells in outer and middle retina eventuating in action potentials at the inner retinal amacrine and ganglion cell levels. Unlike traditional photoreceptors, ganglion cells in the inner retina (intrinsically photosensitive retinal ganglion cells, ipRGCs) absorb short wavelength, blue light utilizing their photopigment melanopsin. Assessment across multiple species show that the ipRGCs mediate myriad visual and non-visual functions including photo-entrainment and circadian rhythms, the pupillary light reflex, sleep, alertness, cognition, mood, and even conscious visual perception. Some ipRGC functions can persist despite blindness in animal models and humans exemplifying their multidisciplinary control of visual and non-visual functions. In previous research we used selective chromatic adaptation (blue stimulus on a bright amber field) to suppress input from rods, red and green sensitive cones to identify retinal and cortical responses from ipRGCs. Herein we used a similar approach, coupled with a filter to block input from blue sensitive cones, to develop a clinically expedient method to measure the full-field, putative visual threshold from human ipRGCs. This metric may expand our ability to detect, diagnose and monitor ocular and neurologic disease and provide a global retinal metric of ipRGCs as a potential outcome measure for studies using gene therapy to arrest and/or improve vision in hereditary retinal diseases.

Beyond 20/20: new clinical methods to quantify vision performance.

OBJECTIVE: To describe the design, the sensitivity, and the application of new methods to quantify visual performance. METHODS: The super vision test-night vision goggle (SVT-NVG) is a new clinical letter chart that measures high- and low-contrast vision under daytime and simulated night conditions. The cone contrast test (CCT) is a computer-based color test that readily diagnoses type and severity of color deficiency. RESULTS: The SVT-NVG reveals subtle decrements from normal not detected by standard visual acuity. The CCT shows 100% sensitivity for the detection of hereditary red or green color deficiency and reveals acquired deficiency as an early sign of disease. CONCLUSIONS: The SVT-NVG and CCT provide rapid, sensitive indices of color and spatial vision potentially linkable to real-world operational demands.

Effect of brimonidine tartrate 0.15% on night-vision difficulty and contrast testing after refractive surgery.

PURPOSE: To evaluate the efficacy of brimonidine tartrate ophthalmic solution 0.15% in patients with night-vision difficulties after laser refractive surgery. SETTING: Center for Refractive Surgery, Walter Reed Army Medical Center, Washington, District of Columbia, USA. METHODS: Six patients with significant night-vision complaints after refractive surgery were enrolled in this study after other treatable causes of night-vision difficulty such as residual refractive error and dry eye were excluded. Low-contrast visual acuity (LCVA) over a range of contrasts (1.25% to 25%) and small letter contrast sensitivity were tested at photopic (100 cd/m(2)) and mesopic (1 cd/m(2)) luminance levels, with and without a standard glare source. Testing was performed before brimonidine tartrate ophthalmic solution 0.15% was administered. Measurements were repeated 1 hour and 1 month after the use of brimonidine tartrate. RESULTS: One hour after using brimonidine tartrate 0.15% solution, patients had significant improvement in LCVA, LCVA with glare, and contrast sensitivity. After 1 month of treatment, all 6 patients reported subjective improvement in night vision and there was a significant difference in performance in mesopic LCVA and mesopic LCVA with glare. The mean pupil size before administration of brimonidine tartrate ophthalmic solution 0.15% was 6.44 mm +/- 1.11 (SD). Pupil size 1 hour after instillation had decreased to 4.53 +/- 1.27 mm and at 1 month had increased to 6.50 +/- 0.94 mm. CONCLUSION: Brimonidine tartrate ophthalmic solution 0.15% improved contrast sensitivity and acuity and decreased night-vision difficulty for up to 1 month in patients with significant complaints after refractive surgery.

Effects of Milk vs Dark Chocolate Consumption on Visual Acuity and Contrast Sensitivity Within 2 Hours: A Randomized Clinical Trial.

Importance: Consumption of dark chocolate can improve blood flow, mood, and cognition in the short term, but little is known about the possible effects of dark chocolate on visual performance. Objective: To compare the short-term effects of consumption of dark chocolate with those of milk chocolate on visual acuity and large- and small-letter contrast sensitivity. Design: A randomized, single-masked crossover design was used to assess short-term visual performance after consumption of a dark or a milk chocolate bar. Thirty participants without pathologic eye disease each consumed dark and milk chocolate in separate sessions, and within-participant paired comparisons were used to assess outcomes. Testing was conducted at the Rosenberg School of Optometry from June 25 to August 15, 2017. Main Outcomes and Measures: Visual acuity (in logMAR units) and large- and small-letter contrast sensitivity (in the log of the inverse of the minimum detectable contrast [logCS units]) were measured 1.75 hours after consumption of dark and milk chocolate bars. Results: Among the 30 participants (9 men and 21 women; mean [SD] age, 26 [5] years), small-letter contrast sensitivity was significantly higher after consumption of dark chocolate (mean [SE], 1.45 [0.04] logCS) vs milk chocolate (mean [SE], 1.30 [0.05] logCS; mean improvement, 0.15 logCS [95% CI, 0.08-0.22 logCS]; P < .001). Large-letter contrast sensitivity was slightly higher after consumption of dark chocolate (mean [SE], 2.05 [0.02] logCS) vs milk chocolate (mean [SE], 2.00 [0.02] logCS; mean improvement, 0.05 logCS [95% CI, 0.00-0.10 logCS]; P = .07). Visual acuity improved slightly after consumption of dark chocolate (mean [SE], -0.22 [0.01] logMAR; visual acuity, approximately 20/12) and milk chocolate (mean [SE], -0.18 [0.01] logMAR; visual acuity, approximately 20/15; mean improvement, 0.04 logMAR [95% CI, 0.02-0.06 logMAR]; P = .05). Composite scores combining results from all tests showed significant improvement after consumption of dark compared with milk chocolate (mean improvement, 0.20 log U [95% CI, 0.10-0.30 log U]; P < .001). Conclusions and Relevance: Contrast sensitivity and visual acuity were significantly higher 2 hours after consumption of a dark chocolate bar compared with a milk chocolate bar, but the duration of these effects and their influence in real-world performance await further testing. Trial Registration: clinicaltrials.gov Identifier: NCT03326934.

Binocular facilitation of cone-specific visual evoked potentials in colour deficiency.

BACKGROUND: Neural compensatory mechanisms have been proposed, which preserve the binocular visual field in glaucoma, as well as cognition in Alzheimer's disease and motor function in Parkinson's disease. It is conceivable that comparable mechanisms operate to preserve function in congenital and/or dystrophic disease. In hereditary colour vision deficiency (CVD), we observed significant facilitation in the amplitude of the binocular cone-specific visual evoked potential (VEP) compared to the monocular amplitude for the cone type corresponding to the CVD. We propose that this finding may reflect preservation of function in hereditary colour vision deficiency. METHODS: Binocular and monocular L, M and S cone-specific VEPs were recorded from 12 colour vision deficient subjects and 17 with normal colour vision, confirmed to be CVD or normal on a battery of colour vision tests. Binocular VEP amplitudes were compared to monocular amplitudes within subjects and between subject groups. RESULTS: Subjects with CVDs showed binocular facilitation of VEP amplitude (enhancement more than 2.0 times; mean: 2.8 times, p = 0.0003) for the cone type corresponding to their CVD. Mean facilitation of 2.8 times exceeded binocular enhancement for other cone types within CVDs (2.8 times versus 1.2 times) and compared to colour vision normals (2.8 times versus 1.2 times). CONCLUSIONS: Hereditary CVDs show binocular facilitation of cone VEP signals for the cone type corresponding to their CVD. As CVD is typically assessed with foveal stimuli, our findings using wider-field binocular stimulation suggest that enhanced colour perception may occur in CVD across a more extensive area of visual field. These results may relate to binocular visual field enhancement in glaucoma and improved colour vision in CVD at supra-threshold levels of stimulation.

Contrast Sensitivity After Wavefront-Guided and Wavefront-Optimized PRK and LASIK for Myopia and Myopic Astigmatism.

PURPOSE: To compare contrast sensitivity among participants undergoing wavefront-guided or wavefront-optimized photorefractive keratectomy (PRK) or LASIK for the treatment of myopia or myopic astigmatism 12 months after surgery. METHODS: In a prospective, randomized clinical trial, 215 participants with myopia ranging from -0.50 to -7.25 diopters (D) and less than -3.50 D of manifest astigmatism electing to undergo either LASIK or PRK were randomized to receive wavefront-guided or wavefront-optimized treatment. Corrected Super Vision Test (Precision Vision, La Salle, IL) high contrast and small letter contrast sensitivity, uncorrected postoperative contrast sensitivity function, and uncorrected and corrected distance visual acuity were measured preoperatively and at 1, 3, 6, and 12 months postoperatively. RESULTS: There was a significant difference within each of the four groups over time when measuring high contrast visual acuity (P < .001) and small letter contrast sensitivity (P < .001), with the most significant decrease occurring 1 month postoperatively. However, there were no significant differences when comparing the four groups for high contrast sensitivity (P = .22) or small letter contrast sensitivity (P = .06). The area under the logarithm of contrast sensitivity function did not differ significantly over time (P = .09) or between groups (P = .16). A pairwise comparison of preoperative to 12-month CDVA showed a significant improvement in all groups (P < .017). The change in CDVA was also significantly different between groups as determined by one-way analysis of variance (P = .003). CONCLUSIONS: Wavefront-guided and wavefront-optimized PRK and LASIK procedures maintained high contrast, small letter contrast sensitivity, and contrast sensitivity function 12 months postoperatively. Although the recovery period for visual performance was longer for PRK versus LASIK, there was no significant difference in treatment type or treatment profile at 12 months postoperatively. [J Refract Surg. 2018;34(9):590-596.].

Night firing range performance following photorefractive keratectomy and laser in situ keratomileusis.

OBJECTIVE: To investigate the effect of laser refractive surgery on night weapons firing. METHODS: Firing range performance was measured at baseline and postoperatively following photorefractive keratectomy and laser in situ keratomileusis. Subjects fired the M-16A2 rifle with night vision goggles (NVG) at starlight, and with iron sight (simulated dusk). Scores, before and after surgery, were compared for both conditions. RESULTS: No subject was able to acquire the target using iron sight without correction before surgery. After surgery, the scores without correction (95.9 +/- 4.7) matched the preoperative scores with correction (94.3 +/- 4.0; p = 0.324). Uncorrected NVG scores after surgery (96.4 +/- 3.1) exceeded the corrected scores before surgery (91.4 +/- 10.2), but this trend was not statistically significant (p = 0.063). CONCLUSION: Night weapon firing with both the iron sight and the NVG sight improved after surgery. This study supports the operational benefits of refractive surgery in the military.

A prospective study of the EYEPORT vision training system.

BACKGROUND: The purpose of this study was to determine if vision training with the EYEPORT system affects vision and reading performance. (Subsequent to this study, the "E.Y.E." has been renamed "EYEPORT") METHODS: College students with normal vision (n = 31) participated in a blind, crossover study to assess within-subject and between-group effects of EYEPORT training. Half the subjects initially underwent training (10 minutes per day, 6 days a week for 3 weeks), and then crossed over to the no-train control condition (3 weeks); the other half underwent the reverse sequence. Vision and reading performance were assessed at baseline, 3 weeks, and 6 weeks. RESULTS: Multivariate analyses (Hotelling's T2) found small improvements in vergence and accommodative facility, reading performance, and stereopsis response time after EYEPORT training (P < 0.025). Enhancements in reading performance and vergence facility were still present 3 weeks after cessation of training (P < 0.001). CONCLUSIONS: The EYEPORT training system shows potential to enhance visual performance and reading ability. Studies are underway to assess its efficacy in symptomatic populations.

Blue-Black or White-Gold? Early Stage Processing and the Color of 'The Dress'.

PURPOSE: In Feb 2015 an image of a dress posted on Tumblr triggered an internet phenomenon: Is the Dress blue and black (BB) or white and gold (WG)? Many claim BB and others insist WG while the true colors are BB. The prevailing theory is that assumptions about the illuminant govern perception of the Dress with WG due to bluish lighting and BB due to yellowish. Our purpose was to determine if early stage optical, retinal and/or neural factors also impact perception of the Dress. METHODS: Thirty-nine subjects were categorized as BB or WG based on their initial perception of the Dress and their perception reported when viewing the Dress on iPhone 5, iPad, and 22" LCD displays. Macular pigment optical density (MPOD) measured with the QuantifEye™ MPS II and visual brainwaves (VEPs) in response to brief presentations of a transparency of the Dress illuminated by a flashing light were measured on each subject and compared between BB and WG groups. Additionally, CIE chromaticity (color) and luminance (brightness) were measured from multiple areas of the Dress image to determine cone stimulation and contrast. RESULTS: Mean MPOD was higher in the WG group (0.49) vs. the BB (0.41, p = 0.04) and median values were higher as well (WG = 0.46, BB = 0.36, p = 0.03). There was no difference in VEP amplitude between groups (p > 0.85) but mean VEP latency was longer in WG (130 msec.) vs. the BB group (107 msec., p = 0.0005). Colorimetry of the Dress showed significantly greater stimulation of blue cones (contrast = 73%) vs. red and green sensitive cones (contrast = 13%). CONCLUSIONS: Our findings indicate that observers with denser MPOD may be predisposed to perceive the Dress as WG due to great absorption of blue light by the macular pigment. Moreover, the novel, substantial stimulation of blue cones by the Dress may contribute to ambiguity and dichotomous perception since the blue cones are so sparse in the retina. Finally, the delayed WG VEPs indicate distinct neural processing in perception of the consistent with fMRI evidence that the WG percept is processed at higher cortical levels than the BB. These results do not fully explain the dichotomous perception of the Dress but do exemplify the need to consider early stage processing when elucidating ambiguous percepts and figures.

Diagnosis of Normal and Abnormal Color Vision with Cone-Specific VEPs.

PURPOSE: Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary "red-green" color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests. METHODS: A calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity. RESULTS: Cone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs (P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs (P > 0.29). CONCLUSIONS: Cone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases. TRANSLATIONAL RELEVANCE: This paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.