Investigation of the color discrimination ability using the Farnsworth-Munsell 100-hue test and structural changes by SS-OCT in patients with transfusion-dependent beta-thalassemia.

AIM: This study aimed to examine the color discrimination ability of patients with transfusion-dependent beta-thalassemia (TDß-T) in detail using the Farnsworth Munsell (FM) 100-hue test and to evaluate structural changes by swept source-optical coherence tomography (SS-OCT). MATERIAL AND METHODS: This prospective, sectional study included 40 patients (79 eyes) with TDß-T and 21 controls (42 eyes). The volunteers underwent a detailed ophthalmological examination and SS-OCT (DRI-OCT, Triton) imaging. Excluded were those with congenital color vision defects detected with the Ishihara pseudoisochromatic test. The patients' color vision was examined using the FM 100-hue test. The total error score (TES), the blue-yellow local error score (b-y LES), and the red-green local error score (r-g LES) were calculated. p <0.05 was considered significant. RESULTS: The mean age was 30.34±6.94 years in the patient group and 32.26±6.43 years in the control group (p = 0.078). The patient group had a significantly lower hemoglobin level (9.25±0.87 g/dL vs. 14±1.79 g/dL, p <0.001) and a significantly higher ferritin level (2665.56±2658.05 µg/L vs. 52.87±69.59 µg/L, p<0.001) compared to the control group. The mean TES, b-y LES, and r-g LES were higher in the patients than in the controls (64.84±30.18 vs. 28.45±16.55, p<0.001, 34.21±17.54 vs. 15.67±10.07, p <0.001, and 29.32±15.72 vs. 12.12±7.94, p<0.001, respectively). The patients had a higher b-y LES than r-g LES (34.21±17.54 vs. 29.32±15.72, p = 0.015). Choroidal thickness was lower in the patients than in the controls (284.34±63.55 µm vs. 324.98±88.05 µm, p = 0.043). CONCLUSION: We found that the color discrimination ability of the patients with TDß-T was reduced in both the r-g and b-y color axes compared to the controls, and their color discrimination ability in the b-y color axis was more affected than in the r-g axis.

Optical coherence tomography angiography findings in transfusion-dependent beta-thalassemia patients with and without splenectomy.

BACKGROUND: Ocular involvement is common in transfusion-dependent beta-thalassemia (TDß-T) patients. We aimed to investigate the effect of splenectomy on optical coherence tomography angiography (OCTA) findings in TDß-T patients. METHODS: The study is a prospective cross-sectional study. A total of 45 eyes of 23 patients with splenectomy (34.04±8.83 years), 18 eyes of 9 patients without splenectomy (27.44±5.43 years), and 54 eyes of 27 controls (33.22±6.44 years) were included. Vessel density in superficial capillary plexus, deep capillary plexus and radial peripapillary capillary, foveal avascular zone, choriocapillaris flow area, choroidal and retinal thickness detected by OCTA were evaluated. p < 0.05 was considered significant. RESULTS: Vessel density of superficial capillary plexus and deep capillary plexus were similar in patients with and without splenectomy, and controls. Choriocapillaris flow area was significantly decreased in patients with splenectomy than that in those without splenectomy and controls (2.02±0.12 vs. 2.17±0.1 and 2.14±0.12; p < 0.001). Choroidal thickness was significantly lower in patients without splenectomy than in patients with splenectomy and controls (260.05±61.02 vs. 305.11±42.13 and 298.89±29.14, p = 0.008). Parafoveal and perifoveal thickness of the full retina and outer retina were significantly lower in patients without splenectomy than in patients with splenectomy and controls (301.06±10.0, 279.78±10.28 vs. 311.04±14.89, 290.87±13.67 and 316.63±13.57, 289.56±9.31, p < 0.001 and p = 0.002; 174.72±7.81, 167.17±6.21 vs. 182.87±8.81, 173.60±7.09 and 185.11±9.26, 173.96±6.79, p = 0.001 and p < 0.001, respectively). CONCLUSIONS: OCTA findings can provide information about the microvascular effects of splenectomy on the retina of patients with TDß-T.

Investigation of relationship between colour discrimination ability and stereoscopic acuity using Farnsworth Munsell 100 hue test and stereo tests.

OBJECTIVE: To evaluate the effect of colour discrimination ability on the stereoscopic acuity by comparing individuals having congenital colour vision deficiency (CCVD) with healthy individuals. DESIGN: A comparative study. PARTICIPANTS: The study included 53 binocular males, of whom 26 (mean age, 36.04 ± 9.30 years) were in the healthy group and 27 (mean age, 33.04 ± 9.81 years) were in the CCVD group. METHODS: The following tests were used: the Ishihara pseudo-isochromatic plate test for detecting CCVD, the Farnsworth Munsell 100 (FM100) hue test for colour discrimination ability, the TNO and Titmus stereo tests for stereoscopic acuity. RESULTS: In the CCVD group, 20 males were deutan and 7 males were protan. According to the FM100 hue test, total error score (TES), blue/yellow (b/y) local error score (LES), and red/green LES were significantly lower in the healthy group (30.23 ± 18.78, 15.15 ± 10.38, and 13.88 ± 11.93, respectively) than in the CCVD group (133.59 ± 67.45, 41.15 ± 22.03, and 89.15 ± 52.16, respectively) (p < 0.01 for each). The stereo test scores revealed significantly higher stereoscopic acuity in the healthy group (43.85 ± 33.92 arcsec for the TNO test and 40.00 ± 0.00 arcsec for the Titmus test) than in the CCVD group (93.33 ± 90.51 arcsec for TNO stereo test and 52.96 ± 24.62 arcsec for the Titmus test) (p < 0.05 for each). The TNO test score was significantly and positively correlated with the TES (r = 0.390, p = 0.049) and b/y LES (r = 0.490, p = 0.011) in the healthy group. CONCLUSIONS: Colour discrimination ability affected stereoscopic acuity. Moreover, stereoscopic acuity increased with increasing colour discrimination ability, which could be originated from the b/y colour region.

Colour vision in juvenile myoclonic epilepsy.

To determine the integrity of colour perception, related to photic sensitivity, in patients with juvenile myoclonic epilepsy. Twenty-four patients with photoparoxysmal response, 27 patients without photoparoxysmal response, and 32 healthy individuals were investigated using the Farnsworth Munsell-100 Hue test to calculate error scores for total colour, blue/yellow, and red/green. No significant differences were observed regarding blue/yellow, red/green or total error score between juvenile myoclonic epilepsy patients with or without photoparoxysmal response. However, the data for all three scores were significantly higher in both patient groups compared to the healthy control group. In both patient groups, the blue/yellow error score was significantly higher than the red/green error score. We were unable to identify a relationship between photoparoxysmal response and colour vision in patients with juvenile myoclonic epilepsy. We believe that the underlying reason why juvenile myoclonic epilepsy patients had significantly higher blue/yellow, red/green, and total error score compared to the healthy control group may be due to GABA dysfunction, which is considered to play a role in the pathophysiology of this disease as well as the physiology of colour vision.

The effect of splenectomy on complement regulatory proteins in erythrocytes in ß-thalassemia major.

INTRODUCTION: Hemolysis due to ineffective erythropoiesis is a serious problem ß-thalassemia major (ß-TM) patients. The role of complement system in the etiopathogenesis of hemolysis observed in ß-TM were released. Hemolysis induced by activation of complement system is prevented by complement regulatory proteins. Decay accelerating factor (CD55), membrane inhibitor of reactive lysis (CD59), and complement reception 1 (CR1, CD35) are among these proteins. The absence of these proteins thus accounts for the increased susceptibility of erythrocytes to complement lysis. Splenomegaly and hypersplenism are common complications among thalassemia major patients necessitating splenectomy. MATERIAL AND METHODS: In this study we investigated how splenectomy effects complement regulatory system in erythrocytes. We analysed CD35, CD55, and CD59 levels on erythrocytes in ß-TM by flow cytometry. RESULTS: The overall mean percentage of CD55 and CD35 positive RBCs of group 1 (22 ß-TM with splenectomy) was significantly lower than group 2 (23 ß-TM without splenectomy) and group 3 (healthy controls) (p < 0.05). The overall mean percentage CD59 positive RBCs of patients was no significantly different in all groups. The levels of CD35 and CD55 expression on the erythrocytes of splenectomized patients was significantly lower than non-splenectomized patients (p < 0.05). CONCLUSIONS: Increased erythrocyte destruction and iron deposition in organs due to deficiency of these regulatory proteins may be the underlying mechanism of organ damage developing in ß-TM patients.

Color vision testing versus pattern visual evoked potentials and optical coherence tomography parameters in subclinical optic nerve involvement in multiple sclerosis.

Acute idiopathic demyelinating optic neuritis is frequently the initial manifestation of multiple sclerosis (MS). We aimed to discuss the value of color vision testing to detect possible optic nerve involvement in patients with MS who had no history of optic neuritis. We evaluated color vision with Farnsworth-Munsell 100 (FM-100) hue test. Total error scores (TES), partial error scores for the red-green axis (RGS) and blue-yellow axis (BYS) were calculated. Topographic optic disc parameters (RNFL, RA, DA, CV, RV, and vertical C/D ratio), total macular volume (TMV), central macular thickness (CMT), and retinal ganglion cell layer (RGCL) were determined using spectral domain optical coherence tomography (SD-OCT). Choroidal thickness (CT) was measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Pattern visual evoked potentials (PVEP) were also performed. Twenty-eight patients with RRMS (56 eyes) and 25 healthy controls (50 eyes) were included. P100 latencies were significantly delayed and P100 amplitudes were significantly reduced in the patient group compared with the controls (p ≤ 0.05). Statistically significant thinning was found in temporal quadrant in the patient group compared with the controls (p = 0.002). TES RGS, and BYS were all increased in the patient group but this was not statistically significant. We found no correlation between TES, RGS, BYS, and P100 latencies or OCT parameters. In our investigation as to whether color vision testing could be a simple biomarker for showing neurodegeneration of the anterior visual pathway regardless of optic neuritis, PVEP and OCT-assessed RNFL thickness seemed to be a more valuable biomarker than color vision testing.

Relation of eye dominancy with color vision discrimination performance ability in normal subjects.

AIM: To evaluate the performance of dominant eye (DE) for color vision discrimination ability among the medical students with normal color vision. METHODS: Total of 50 students studying at Baskent University Faculty of Medicine, including 31 males (62%) and 19 females (38%), with visual acuity of 20/20 and without congenital color vision deficiency (CCVD) evaluated by Ishihara pseudoisochromatic plate test (IPPT) were recruited for this prospective comparative study upon their voluntary participation. DE was determined by the Gündogan Method. The color discrimination ability was examined with the Farnsworth-Munsell 100 hue (FM100) test. Test was applied by two days interval to all subjects for the three times while two eyes (TE), right eye (RE) and left eye (LE) were seeing for detecting red-green (r/g), blue-yellow (b/y) local color spectral regions error scores. The error scores were evaluated for both in DE and non-dominant (NDE). P values below 0.05 were considered to be statistically significant. RESULTS: The students aged 21.18±2.52 years (mean±SD). Without sex difference the RE and the LE dominancy were found 22 (44%) and 28 (56%) respectively and FM 100 test total error scores of DE in both r/g-b/y regions were found without gender difference 24.12±14.70, 34.68±18.95, respectively. For the NDE in both, r/g-b/y regions error scores without gender difference were 32.20±19.21, 36.24±17.56, respectively. The difference of total error scores between the DE and NDE was found as 58.80±29.92, 68.44±31.46. The statistical differences among the DE and the NDE in r/g local region and total error scores were found significant in both genders (P<0.05, P<0.001). CONCLUSION: The color vision discrimination performance ability was found prominent for DE. This superiority was attributed to higher sensitivity of the r/g local color spectral region. We conclude that DE has priority in r/g color spectral region, probably including inhibition of NDE.