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PubMedDate not supplied

[Ophthalmological assessment of professionally significant functions in persons undergone laser myopia correction].

Professionally significant functions (visual acuity, color vision and its parameters, and dark adaptation and its parameters) were determined in moderate and severe myopia before and after its excimer laser correction by the LASIK method: in early (1, 3 months) and late (6, 12 months) periods after surgery to decide where the operated persons are allowed to have the jobs associated with railway traffic safety. Sixty-one patients with moderate and severe myopia and 23 control individuals were examined at the Moscow Research and Technological Complex "Eye Surgery". The examinations have demonstrated that the values of visual acuity, color vision, and dark adaptation considerably improved. Whether the persons undergone excimer laser myopia correction are allowed to have the jobs associated with railway transport safety should be individually decided, by taking into account the postoperative recovery of professionally significant visual functions.

Adolescent↗
PubMedDate not supplied

Pigmented paravenous retinochoroidal atrophy. A literature review supported by seven cases.

Seven patients (4 men and 3 women, ranging in age from 27 to 64 years) with pigmented paravenous retinochoroidal atrophy, a rare disorder of unknown origin, were studied. The mean follow-up time was 18.5 months. Fundus examinations were performed, and color fundus photographs were taken. In addition to fluorescein angiography, visual field examinations, color vision and electroretinographic tests were performed. All 7 patients were asymptomatic, with visual acuities ranging from 3/10 to 10/10. Both fundi showed patches of retinochoroidal atrophy and pigmentation along the retinal veins in all patients. Fluorescein angiography showed hyperfluorescence due to the pigment epithelial atrophy together with hypofluorescence corresponding to bone spicule pigment clumping. Visual field tests showed scotomas corresponding with areas of atrophy along the retinal veins. The electroretinography showed reduced responses in 2 cases. Color vision was normal in all cases. The patients had no history of trauma or a previous inflammatory process. Serology for syphilis, Toxoplasma and cytomegalovirus as well as a skin test for tuberculosis were negative. When the patients were seen at the end of the follow-up period, no variation of the findings was noted. Although the fundus abnormalities can be mild or severe, retinal function tests indicated that this is a geographic and not a generalized disorder.

Adult↗
PubMed1995

Pattern electroretinogram, visual evoked potential and psychophysical functions in maculopathy.

To compare pattern electroretinograms and visual evoked potentials with psychophysical examinations, such as visual acuity, static (automated) perimetry and color vision in unilateral maculopathies of various origins, 20 patients with unilateral retinal diseases within the macula and the posterior pole were tested. Pattern electroretinography, visual evoked potential testing and static perimetry (Octopus program M1) were performed with three different test field sizes (20 degrees x 20 degrees, 10 degrees x 10 degrees and 6 degrees x 6 degrees). The best correlation in all three test field sizes was found between visual acuity, static perimetry and visual evoked potential. This result is surprising, since central area defined functions (visual evoked potentials, visual acuity) correlated well with a total area integrating function (mean defect in static perimetry. The pattern electroretinogram, which seems to reflect an area-related function as well, showed a correlation to static perimetry only in the smaller 10 degrees x 10 degrees and 6 degrees x 6 degrees fields and not a significant correlation in the 20 degrees x 20 degrees field. Smaller stimulation fields may therefore produce sharper results in pattern electroretinographic testing. There was no correlation between pattern electroretinograms and visual evoked potentials or visual acuity. The pattern electroretinogram was recorded under monocular and binocular viewing conditions. In 60% of the patients, the amplitude of the affected eye was more reduced in the monocular than the binocular viewing condition; the healthy fellow eye controlled stable fixation of the affected eye more readily during binocular pattern electroretinogram registration. The degree of the color vision disturbance (C-index, desaturated panel D-15 test) did not correlate to any of the other examinations.

Adolescent↗
PubMed1989

Spectral sensitivity of cones in an ungulate.

Ungulates have been classified as having arrhythmic eyes in the sense that they contain features appropriate both to diurnal and nocturnal life. The former is typically associated with multiple classes of cones and a color-vision capacity. To see if an arrhythmic animal has these features, the number of cone classes was determined and the spectra of these cones were measured in a common ungulate, the domestic pig (Sus scrofa). Examination with electroretinogram (ERG) flicker photometry revealed the presence of two classes of cones in the pig's eye having average maximum sensitivity (lambda max) at 439 nm and 556 nm, respectively. This ungulate thus has the requisite retinal basis for dichromatic color vision.

Animals↗
PubMedDate not supplied

The visual pigments of the bottlenose dolphin (Tursiops truncatus).

To assess the dolphin's capacity for color vision and determine the absorption maxima of the dolphin visual pigments, we have cloned and expressed the dolphin opsin genes. On the basis of sequence homology with other mammalian opsins, a dolphin rod and long-wavelength sensitive (LWS) cone opsin cDNAs were identified. Both dolphin opsin cDNAs were expressed in mammalian COS-7 cells. The resulting proteins were reconstituted with the chromophore 11-cis-retinal resulting in functional pigments with absorption maxima (lambdamax) of 488 and 524 nm for the rod and cone pigments respectively. These lambdamax values are considerably blue shifted compared to those of many terrestrial mammals. Although the dolphin possesses a gene homologous to other mammalian short-wavelength sensitive (SWS) opsins, it is not expressed in vivo and has accumulated a number of deletions, including a frame-shift mutation at nucleotide position 31. The dolphin therefore lacks the common dichromatic form of color vision typical of most terrestrial mammals.

Amino Acid Sequence↗
PubMed2001

Genomic and spectral analyses of long to middle wavelength-sensitive visual pigments of common marmoset (Callithrix jacchus).

The genetic basis of red-green color vision of common marmoset (Callithrix jacchus) is not fully understood. Here, we have cloned and characterized the three alleles at a locus that encode the long to middle wavelength-sensitive (LWS/MWS) visual pigments of this species. Using in situ hybridization, we localized this locus to the telomeric region of the long arm of X chromosome. The three visual pigments achieve the wavelengths of maximal absorption at 561, 553, and 539 nm and fully explain the red-green color vision of the common marmoset. The 'tri-allelic single-locus X-chromosome' model operates under the unique phenomenon, known as blood chimerism.

Animals↗
PubMed2005

Novel NR2E3 mutations (R104Q, R334G) associated with a mild form of enhanced S-cone syndrome demonstrate compound heterozygosity.

PURPOSE: We investigated the ophthalmic features of a mild form of enhanced S-cone syndrome (ESCS) in a 33-year-old Japanese female proband and 3 unaffected family members. A genetic analysis was performed. DESIGN: Genetic and observational case study. METHODS: Fundus examinations, optical coherence tomography (OCT), Goldmann visual field (VF) perimetry, color vision tests, spectral sensitivity, and full-field and spectral electroretinography (ERG) were performed. Mutation screening of the NR2E3 gene, which encodes a photoreceptor-specific orphan nuclear receptor, was performed with polymerase chain reaction amplification and direct sequencing. MAIN OUTCOME MEASURES: Mutations in the NR2E3 gene, fundus photographs, OCT images, VFs, spectral sensitivity, and ERG findings. RESULTS: The diagnosis of ESCS was made based on the distinctive spectral ERG findings: hypersensitivity to blue stimuli and hyposensitivity to red stimuli. The proband had good visual acuity, normal color vision, good central VFs, and nearly normal spectral sensitivity. Funduscopy showed degenerative lesions in the vascular arcades to the midperipheral retina. The OCT images showed a morphologically normal macular thickness. In the full-field ERG, low amplitudes of rod b-waves were detected. Waveforms between rod-plus-cone and cone ERGs were very similar. Mutation analysis identified 2 novel compound heterozygous missense mutations, p.R104Q and p.R334G, which reside in the DNA-binding domain (DBD) and ligand-binding domain (LBD), respectively. The unaffected parents carried one of these mutations each, consistent with autosomal recessive transmission. CONCLUSIONS: Our study suggests that the expression of these 2 mutants of NR2E3, acting as a dimer, is correlated with a mild form of ESCS in that full foveal function and retinal laminar structure are maintained, and certain rod responses are present. This may be explained by the possibility that the heterodimers encoded by the 2 mutant alleles retain certain NR2E3 functions through the respective intact DBD and LBD.

Adult↗
PubMed1999

Bilateral macular atrophy in blue cone monochromacy (BCM) with loss of the locus control region (LCR) and part of the red pigment gene.

PURPOSE: To describe unusual macular abnormalities in a family with blue cone monochromacy (BCM, or X-linked incomplete achromatopsia) and deletion of about 9.5 kb comprising part of the red pigment gene and the region upstream of the red pigment gene. METHODS: The molecular structure of the red and green pigment genes and the locus control region (LCR) upstream of the red gene were studied for deletions, rearrangements and point mutations by Southern blot analysis and PCR. Four affected males (ages 33, 45, 51, and 59) and a carrier female (age 58) were examined by funduscopy and fluorescein angiography. Extensive color vision testing as well as rod and cone electroretinography (ERG) were performed on two of them. RESULTS: Analysis showed that the 6 kb proximal red gene region, exon 1 and about 3.1 kb of intron 1 of the red gene are deleted in this family. Exons 2-6 of the red gene, all the exons of the green gene and the Tex 28 gene were present. Four affected males had bilateral macular changes, including three with overt atrophy. All had visual acuity of 20/200 and their color vision was typical for BCM, with the absence of long- and middle-wavelength sensitive cone function. The ERG showed normal rod responses, whereas the photopic cone and 30-Hz flicker responses were >95% reduced. CONCLUSIONS: We report the unusual association between macular atrophy and BCM resulting from the loss of an approximately 9.5 kb region encompassing the LCR, proximal red gene promoter elements and exon 1 of the red gene. However, loss of the LCR and promoter is not sufficient to explain the phenotype since we have observed other BCM families with similar deletions who do not exhibit macular changes.

Adult↗
PubMed2003

Evaluation of visual functions in patients on ethambutol therapy for tuberculosis: a prospective study.

UNLABELLED: To study the incidence of clinical and subclinical optic nerve toxicity with ethambutol therapy in patients with tuberculosis and to evaluate the reversibility of its side effects after cessation of therapy. This prospective randomized controlled study included 60 newly diagnosed adult cases of tuberculosis, who were randomly assigned into two groups. The study group included 30 patients (60eyes) who received ethambutol as a part of their anti-tubercular treatment and the control group included 30 patients (60eyes) who did not receive ethambutol. The patients were examined on monthly basis. The visual parameters studied were best corrected visual acuity, pupillary reactions, optic disc changes, color vision, contrast sensitivity, pupil cycle time, visual field charting and visual evoked potential. Ethambutol was stopped in those patients in whom toxicity was detected and they were followed more frequently. Only one patient (3.3%) showed decrease in visual acuity, three patients (10%) developed visual field defects, two patients (6.7%) showed deterioration of contrast sensitivity, the pupil cycle time was prolonged in one eye and two patients (6.7%) showed abnormal visual evoked potential. During the therapy, all patients in the study group had normal pupillary reactions, fundus picture and color vision. CONCLUSIONS: Ethambutol induced ocular toxicity was seen in three patients (10%) in our study. The maximum visual recovery occurred in first six to eight weeks after stopping ethambutol. The visual recovery was complete in only one patient, but it was partial in two patients i.e. visual fields, contrast sensitivity and visual evoked potential remained abnormal.

Adult↗
PubMed2005

Generation of knock-in mice carrying third cones with spectral sensitivity different from S and L cones.

Red-green color vision in primates is unique in the sense that it is mediated by two photoreceptor cells that are indistinguishable in all aspects except for their visual pigments. In order to generate an animal model for investigation of the interaction between red-green inputs at the molecular level, we applied knock-in technology and X-chromosome inactivation machinery to make a mouse model with cone cells possessing visual pigments with different spectral sensitivities. We introduced a S308A point mutation into the Green opsin gene allele on the X-chromosome. This manipulation generated a 24 nm red-shift of absorption maximum in the cone pigment with negligible functional differences in other molecular properties. Amplitudes of responses in ERG and ganglion cell recordings of homozygotes were similar to those of wild-types, although the spectral sensitivities differed. Heterozygotes showed variable spectral sensitivities of ganglion cell responses due to the different integration of the native and the S308A cone inputs on the dendritic fields. In situ hybridization experiments showed that cone cells with respective pigments formed patch-like clusters of specific L cone-types, approximately 30 mum in diameter, which were randomly distributed in the dorsal region of the retinas. Since the patch-like clustering was arranged by X-inactivation, such clustering could be present in the peripheral retinas of New World monkeys with polymorphic L pigments, indicating that our mice would be a suitable model to study evolution of the mammalian color vision system.

Animals↗
PubMed1989

Retinal periphlebitis after hormonal treatment.

Two cases, those of a man and a woman, developed retinal periphlebitis after hormonal treatment for infertility and contraceptives, respectively. Both had a unilateral severe decrease in visual acuity, and a central scotoma and defect in color vision were also present. The fundus had retinal edema, especially of the macula, a hyperemic disc with blurred margins, normal arteries, congested veins, and marked sheathing along the main veins, with retinal hemorrhages in the inferior half of the retina. Fluorescein angiography showed a delayed filling of the veins in the affected retina and late staining of these veins. Since there was severe visual impairment in each case, systemic adrenocorticosteroids were administered, and a rapid improvement in visual acuity occurred. In one patient, a trace Marcus-Gunn sign, a few small paracentral scotomas, and a defect in color vision were permanent sequelae.

Adult↗
PubMed2006

A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2.

Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation Idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (LOD score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff Syndrome), Leber hereditary optic neuropathy, and Charcot-Marie-Tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.

Chromosomes, Human, X↗
PubMed1998

Visual function in professional truck drivers.

OBJECTIVES: The purpose of this study was to examine the visual function of professional truck drivers at working age to find out whether older drivers had any defective function and should therefore be given less demanding duties at work. METHODS: Of the 100 drivers invited to the study, 77 came to the examination, including 74 men and 3 women aged from 30 to 66 years (mean 50.3+/-10.3 years). In addition to the basic eye examination, visual fields, dark adaptation, contrast sensitivity, color vision, and glare sensitivity were studied. RESULTS: Two drivers (2.6%) had an incipient cataract in one eye, four (5.2%) had slight fundus abnormalities, five (6.5%) had exo- or esotropia, and five (6.5%) had amblyopia. Visual acuity in the better eye varied from 0.4 to 1.2 (mean 1.06+/-0.17) and in the other eye from 0.1 to 1.2 (mean 0.96+/-0.23). Five drivers (6.5%) had inadequate visual acuity for a professional driver's license. Visual fields were interpreted as normal in all drivers. The results of the dark-adaptation, contrast-sensitivity, and glare testing showed values within normal ranges for all drivers. In the color-vision tests, five male drivers (6.8% of the men) had a slight congenital green defect, and two drivers had an acquired blue defect in one eye because of cataract and diabetes. CONCLUSIONS: According to the present study, there is no need to give older drivers less demanding duties because of their eyes. However, one serious finding in the present study needs attention: the visual acuity was lower than that required for a professional driver's license in five drivers. Evidently, more regular checkups of visual acuity are needed for a professional driver's license.

Adaptation, Ocular↗
PubMed2005

Customized, single-incision, three-wall orbital decompression.

PURPOSE: To present the clinical outcome in 55 consecutive patients by using a customized, single-incision, 3-wall orbital decompression. METHODS: A retrospective chart review was performed of 97 customized, single-incision, 3-wall decompressions in 55 consecutive patients within one surgeon's practice. A standardized surgical technique featuring lateral small-incision, 3-wall decompression with specific "strut" preservation was used in all patients. Success of the procedure was assessed on the basis of the amount of proptosis reduction achieved, as measured by the difference in Hertel exophthalmometry measurements, and by improvement in or preservation of preoperative visual acuity and color vision in the setting of compressive optic neuropathy. Subjective diplopia was recorded before and after surgery, as was the presence of extraocular muscle restriction. RESULTS: A total of 97 orbital decompressions in 55 consecutive patients were reviewed. The majority of surgeries were performed for disfiguring proptosis with some degree of exposure-related symptoms (81%), with other indications including compressive optic neuropathy (17%), and pain (2%). The average amount of proptosis reduction achieved at 3 months was 5 mm (range, 1 to 11 mm). Visual acuity in patients with compressive optic neuropathy improved an average of 2 lines on the standard Snellen chart testing (range, 1 to 5). Color vision improved an average of 5 Ishihara plates (range, 0 to 13). Seventy-one percent of patients had subjective diplopia before surgery; 21% of these patients reported improvement or complete resolution of diplopia after surgery. Of the 29% of patients without preoperative subjective diplopia, all but one (1.8 of total patients) remained symptom free. CONCLUSIONS: We find that a customized, single-incision, 3-wall orbital decompression provides adequate decompression and proptosis reduction while minimizing postoperative strabismus and providing an aesthetically desirable result.

Adult↗
PubMed2003

Evaluation of neuroprotective qualities of brimonidine during LASIK.

PURPOSE: The effects of LASIK-induced increased intraocular pressure on the optic nerve and nerve fiber layer are poorly understood. This study evaluates the effect of LASIK on several optic nerve parameters, both structural (scanning laser polarimetry) and functional (automated perimetry). In addition, the potential neuroprotective effect of perioperative brimonidine is studied. DESIGN: Randomized self-controlled, masked trial. PARTICIPANTS: Fifty-one patients scheduled for routine, bilateral, myopic LASIK. Patients served as their own control and received brimonidine in one eye and placebo in their fellow eye. METHODS: Patients were treated with the VISX Star S3 Excimer Laser. Patients were evaluated preoperatively and at 1 day, 1 month, and 3 months after LASIK. Topical brimonidine or control vehicle was administrated three times daily for 3 days before surgery. In addition, 1 drop of the respective study drug was instilled at the end of the procedure, and the patient continued the study drug three times daily for 3 weeks after surgery in the respective (randomized) eye. MAIN OUTCOME MEASURES: Visual acuity, nerve fiber layer analysis, automated visual field, contrast sensitivity, color vision, and pupillary function. RESULTS: Brimonidine did not change the outcome of any of the parameters analyzed in this study. There was not a statistically significant change in any of the visual field parameters (mean elevation or depression, pattern standard deviation, and corrected pattern standard deviation) measured in either the placebo or brimonidine group postoperatively. However, both the placebo and brimonidine group did show a statistically significant change in many of the direct Nerve Fiber Analyzer GDx (NFA GDx) measures. The average thickness, ellipse, and superior average were generally reduced in both groups. There was, however, no statistically significant change after LASIK in either group in indirect NFA GDx parameters such as symmetry, superior ratio, inferior ratio, or superior/nasal ratio. There was no significant change in optic nerve appearance, contrast sensitivity, or color vision between treatment groups before or after LASIK. CONCLUSIONS: LASIK with or without brimonidine did not affect the structure or function of the parameters of the optic nerve studied. Direct NFA GDx measures were globally reduced after myopic LASIK; however, the ratio measures were generally unaffected. The reduction in direct, retinal nerve fiber layer measures, in the absence of change in ratio measures and other optic nerve parameters and absence of brimonidine effect, suggest an alteration in corneal birefringence after excimer laser ablation.

Administration, Topical↗
PubMed1998

The effect of nimodipine, a centrally active calcium antagonist, on visual function and mascular blood flow in patients with normal-tension glaucoma and control subjects.

PURPOSE: This study was performed to evaluate the effect of nimodipine, a centrally active calcium channel antagonist on automated Humphrey visual fields, Farnsworth-Munsell 100 (FM-100) hue color vision testing, and macular blood flow (blue field entoptic simulation technique) in patients with normal-tension glaucoma (NTG) and control subjects. METHODS: Thirteen patients with NTG and thirteen age- and sex-matched control subjects were studied in a prospective, placebo-controlled, double-masked, crossover protocol. On each of the two study dates, testing was performed at baseline and 90 minutes after administration of either two 30-mg nimodipine capsules or two identical appearing placebo capsules. Blood pressure and pulse were monitored throughout the study. RESULTS: Nimodipine administration resulted in a performance corrected improvement in Humphrey visual field mean deviation (patients with NTG and control subjects), corrected pattern standard deviation (patients with NTG), and macular sensitivity (the average of the foveal threshold and the four most central points of the visual field; patients with NTG). The FM-100 hue error scores significantly decreased after administration of nimodipine in patients with NTG and control subjects compared with baseline. There were no significant differences in baseline leukocyte velocity or density between patients with NTG and control subjects; no significant changes in leukocyte velocity or density were noted after administration of nimodipine in either group. CONCLUSION: Nimodipine caused a significant performance corrected improvement in visual field testing and a significant improvement in color vision. Nimodipine did not alter macular hemodynamics as measured using the blue field entoptic simulation technique, although results were hampered by high variability, particularly in the leukocyte density measurements.

Aged↗
PubMed2002

Long-term ophthalmic outcome of low birth weight children with and without retinopathy of prematurity.

OBJECTIVE: A prospective study of retinopathy of prematurity (ROP) of 505 infants who weighed <1701 g at birth was undertaken in the mid-1980s. This cohort was traced at 10 to 12 years of age to determine how low birth weight alone and ROP might influence their ophthalmic outcome. METHODS: Outcome measures were 1) visual functions (visual acuity, contrast sensitivity, stereoacuity, perimetry, and color vision), 2) presence of strabismus, and 3), measurements of eye size and the dimensions of its components including refractive state. A total of 169 11-year-olds who were born at term were recruited as control subjects and examined under the same conditions. RESULTS: A total of 448 of the original cohort were traced, and 254 consented to a further examination. Compared with the control group, the follow-up cohort differed significantly with reduced visual functions and increased incidence of both myopia and strabismus. Compared with published data, eye size was smaller in the low birth weight cohort. To summarize the ophthalmic data, we defined ophthalmic morbidity as visual acuity below 0.0 log units or the presence of strabismus, myopia, color vision defect, or visual field defect. The rate of ophthalmic morbidity was 50.8% (n = 129/254) in the study cohort compared with 19.5% (n = 33/169) in the control group. The highest rate of ophthalmic morbidity was associated with severe ROP (stages 3/4), although those with no ROP had a less favorable outcome than the control group. CONCLUSION: This study shows that low birth weight children are at increased risk of visual impairments compared with children who are born at full term. Visual impairments are associated with low birth weight per se and severe ROP. Regressed mild ROP is only a risk factor for strabismus. The functional significance of these deficits is largely unknown.

Case-Control Studies↗
PubMed1990

Loss of P retinal ganglion cell function in resolved optic neuritis.

To determine the relative loss of P and M (X and Y) ganglion cell function in unilateral resolved optic neuritis, 10 patients with 20/20 or better Snellen acuity in both eyes had contrast sensitivity testing, color vision testing, and automated perimetry. We used contrast sensitivity gratings of 0.5 cycles per degree (cpd) with a rate of counterphase temporal modulation of 30 Hz and gratings of 11.4 cpd at 1 Hz. On 1 trial, patients responded when they detected the pattern of the grating and on the next trial when they 1st perceived movement. There was a significant difference in the 1 Hz high spatial frequency pattern and movement results suggesting loss of P cell function. Two patients were unable to perceive any movement with their involved eye with this target, but could detect the pattern. There was no significant difference between the involved and uninvolved eyes in the low spatial frequency pattern detection values. This is a function ascribed to the M cell. There was also loss of low spatial frequency movement detection. Although there was significant depression of the entire visual field in the involved eye, the probability plots showed the most significant loss in the cecocentral area. Farnsworth-Munsell 100 Hue color testing was also abnormal. Greater involvement of P than M ganglion cell axons may explain these contrast sensitivity abnormalities, central scotomata, and color vision loss.

Evoked Potentials, Visual↗