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This study proposes new, original methods for diagnosis of glaucoma optic neuropathy--oscillatory potentials (OP) in an electroretinogram (ERG) to a long-term stimulus and in the 30 Hz flicker ERG (with identification of OP at frequencies of 80 to 120 Hz). Twenty-three patients (46 years) aged 40 to 65 years with primary open-angle glaucoma were examined. OP in the 30 Hz flicker ERG (01 and 02) and that in the ERG ON-response to a long-term stimulus have a similar origin and are linked with the light ON-channels of the retinal cone system. O1, O2, and 03 in the 30 Hz flicker ERG reflect the function of neurons in the retinal cone system. The O3 oscillation displays impaired neuronal communications in the retinal ganglion cells.

The paper gives the results of electroretinography (ERG) in 38 patients (73 eyes) with type 2 diabetes mellitus at different stages of diabetic retinopathy (including in diabetic macular edema). The reductions in the macular ERG (M-ERG) amplitude parameters and in the retinal density of bioelectrical activity and the decreased amplitude and longer latency of multifocal ERG (mfERG) N1 and P1 components evidence the involvement of the retinal macular region into the pathological process and the magnitude of these changes depends on the presence of imaged macular edema. Despite the certain limitations of mfERG, assessment of the topography of retinal bioelectrical activity in the central field of vision is an important supplement to M-ERG results and may be a prognostic criterion for the development of a pathological process and its extent.

The paper presents a procedure and conditions for recording multifocal electroretinogram (mfERG), its origin, and factors influencing small-signal ERG. The optimal conditions of ERG extraction using the existing method are appraised and indications for its use in ophthalmological care defined. The results of comparing the new types of electrodes developed in Russia for ERG recording and a DTL electrode included in the ISCEV guidelines are presented.

Postuveal glaucoma is a severe complication of uveitis and frequently an indirect cause of severe visual acuity disturbance. Early diagnosis and determination of the efficiency of drug therapy and indications for surgical treatment require that the presence and progression of optic neuropathy should be evaluated. Examining the topography of color and contrast sensitivity and the central visual field in patients with postuveal glaucoma and peripheral uveitis has ascertained that progression of a glaucomatous process causes a reduction in the function of dark canals and green cones with the subsequent involvement of the retinal light canals in a pathological process. The decreased contrast sensitivity of the light canals and imperception of red color stimuli are observed during inflammatory processes.

The authors studied the influence of active and passive modulations of ocular microcirculation on the morphometric parameters of the head of the optic nerve and their correlation in patients with primary open-angle glaucoma in the presence of elevated and normalized intraocular pressures (IOP). Ocular microcirculation was examined by the contact method on a LAKK-01 Doppler laser flowmeter. The morphometric parameters were explored by scanning laser ophthalmoscopy on a NRT device. Analysis showed a significant linear correlation of the active and passive modulations of microcirculation with the thickness of a retinal nerve fiber layer, the area and volume of the neuroretinal rim, and the volume profile of excavation in both types of microcirculatory changes. On the bases of the derived ratios, it has been concluded that in patients with the hyperemic type of microcirculation, active modulation mechanisms (enhanced neurogenic and myogenic activities of afferent microvessels) are responsive for glaucomatous optic neuropath in the presence of elevated IOP. In patients with the spastic type, decreased neurogenic and myogenic activities of afferent microvessels are an independent mechanism of tissue damage in the head of the optic nerve in normalized IOP.

Congenital myopia is a particular form of short sight that forms in the intrauterine development of a fetus and that is generally characterized by high myopia, a longer anteroposterior axis (APA) of the eye, and its fundal changes. The authors have studied the functional state of the central and peripheral retinal segments in children with congenital myopia by electric retinography (ERG). They examined 23 patients (46 eyes) aged 6 to 16 years, who had moderate and high congenital myopia, the diagnosis in whom had been established in their early life, with various ophthalmoscopic manifestations: without macular changes, with the hyperpigmented macula, an undifferentiated macular region, and acquired chorioretinal dystrophy. Visometry, refractometry, ophthalmoscopy, ultrasound biometry (APA measurement), and mixed, local, and multifocal ERG were performed. Four patients were diagnosed as having congenital persistent nocturnal blindness of the Schubert-Bornstein type. Varying bioelectrical activity changes in the retinal macular region were revealed in congenital myopia both in the absence of ophthalmoscopic changes and with the changes in the fundus of the eye as macular hyperpigmentation, undifferentiated macular region, and central chorioretinal dystrophy. There was a moderate and high inverse correlation between the parameters of bioelectrical activity (the amplitude of b wave of the maximum ERG, that of b wave of local ERG and the retinal density of a P1 component in all rings) on the one hand, and the spherical equivalent of refraction and the length of ADA, on the other.

The mechanisms of visual dysfunction in high amblyopia have not been adequately investigated. Different types of electroretinograms (ERG) as part of the ISCEV standard, as well as macular (15%) pattern and multifocal ERG were recorded in 41 children aged 5-17 years who had high amblyopia with varying gaze fixation and a visual acuity of 0.03-0.1. In high amblyopia, the mixed, macular, and flicker (30 Hz) ERGs were unchanged; however, some patients had supernormal a-wave of a mixed ERG, subnormal a-a- and b-waves of a macular ERG, and a moderately subnormal ERG pattern. Recording of a multifocal ERG showed lower retinal density values in the first and second rings. Thus, in high amblyopia, there are characteristic retinal bioelectrical activity impairments recorded under different conditions of stimulation and adaptation, which suggest that there are impaired interreceptor relations at the retinal level. These changes statistically significantly differ from those in organic retinal defects, which may be a criterion for their differential diagnosis.

Twenty patients with endocrine ophthalmopathy (EOP) (40 eyes) were examined, of them 11, 14, and 15 eyes were in a state of compensation, subcompensation, and decompensation, respectively. Color Doppler imaging was made in all the patients in order to study blood flow in the ophthalmic artery, retinal central artery, retinal central vein, posterior short ciliary arteries, posterior long ciliary arteries, and superior ophthalmic vein. There was a significant reduction in end diastolic blood flow velocity and a pronounced increase in the orbital arteries, which is typical of the ocular ischemic syndrome. The patients in a stage of EOP decompensation were found to have lowest values of the maximum systolic blood flow velocity in the retinal central vein and superior ophthalmic vein. The higher values of the maximum blood flow velocity in the orbital arteries in patients with decompensated EOP resulted from orbital pathological processes that may be largely determined by congestive processes rather than orbital inflammation.

The paper gives the results of electroretinographic and psychophysical studies in hypertensive patients with first-, second-, and third-degree blood pressure (BP) elevation. The most characteristic functional symptoms of hypertensive retinopathy were defined at different stages of its development. There may be impaired retinal bioelectrical activity and diminished contrast and color sensitivity both in the presence and absence of ophthalmoscopically visible changes. Based on the findings, the authors have developed a functional classification of hypertensive retinopathy in relation to the degree of BP elevation.

A new procedure is proposed to study oscillatory potentials (OP), by using long-term flash ERG. OPs for on- and off-ERG were isolated, by employing mathematical filters (80-200 Hz). This procedure was used to examine 25 healthy subjects and 40 patients with different stages of glaucoma. The procedure could ascertain the site of a pathological process in the on- or off-cone cell system, each showing a different sensitivity. The use of this study opens up new avenues for the study of both pathological processes in the on- and off-cone cell systems from distal to proximal portions and pathogenetic mechanisms responsible for development of retinal and optic nerve diseases.

The paper presents the results of studies made in patients with different stages of primary open-angle glaucoma, by using oscillatory potentials (OP). A significant inverse relationship was established between the OP index and the intraocular pressure; the OPI index was decreased in progressive glaucoma. The findings suggest that neuronal relationships are impaired in the proximal retina in glaucoma due to its ischemic processes.

Optic neuropathy is a serious complication of endocrine ophthalmopathy (EOP). The morphological characteristics of the optic nerve (provided by a Heidelberg, HRT II retinotomograph) were compared with the functional impairments of various canals of light, color, and contrast sensitivities (detected by an Offon programme complex, MBN, Moscow). There were decreases in contrast and color sensitivities just at the early stages of the disease and deteriorated functions of contract and color sensitivity canals as optic neuropathy progressed. The HRT II retinotomograph has shown a significant change in the thickness of optic nerve fibers, the area of the optic disk (OD), and the volume of the neuroretinal ring, which corresponds to the magnitude of clinical manifestations and the severity of OD lesion. The first retinal changes appear long before optic nerve compression at the orbital apex (orbital apex syndrome), which are caused by ischemic and hypoxic processes due to orbital soft tissue edema. The most sensitive test in detecting the latent stage of optic neuropathy in EOP is a color and contrast sensitivity topography test. In EOP, the morphological optic nerve changes correlate with functional impairments in different canals of the visual system, reflecting the stage of the disease.

The paper describes the current types of electroretinography, the origin of electric retinal activity and its role in the diagnosis, differential diagnosis, and monitoring of retinal diseases of various origin. It presents the electroretinographic symptoms typical of pathology of the retinal cone and rod system in some hereditary diseases whose genes have been mapped and cloned to date and whose pathogenesis specified. The current concepts of retinal remodeling in its dystrophic changes are produced and emphasis is laid on the necessity of using the progress of vision biology and physiology in ophthalmological practice.

Described in the paper are the results of a comparative evaluation of treatment of amblyopia by computer techniques based on the modern understanding of the mechanisms of impaired visual functions, as observed in amblyopia, comprising stimulation of different canals of the visual system, which were affected or not. Better clinical-and-functional results were fixed in patients with high amblyopia by using the "Ambcar" soft stimulating the magnocellular system by sinusoidal grates with the eyes being fixed on moving objects as well as in patients with moderate amblyopia by using the "eYe" and "Krestiki" soft tools affecting different canals of the visual system and different levels of the parvocellular system. Amblyopia should be treated with respect to individual differences between affected functions of the visual system in each patient, and a therapy method should be chosen in proportion to a disease severity.

Visual field losses and changes of the optic nerve disk are signs of optic neuropathy in glaucoma; psychophysical and electrophysiological tests can contribute to an early detection of glaucomatous optic neuropathy. Electrophysiological methods, like pattern electroretinogram (PERG) and visual induced cortical potentials can be useful in the diagnosis of glaucoma since they are compatible with the functions of retinal ganglion cells. A combination of psychophysical and electrophysiological examination methods contribute to an early diagnosis of glaucoma because they make it possible to study different aspects of visual functions. The results of psychophysical tests correlate to a greater extent than electrophysiological tests with defects in visual fields. Temporal, temporal-and-spatial contrast sensitivity and visual induced cortical potentials, whose changes are detected in the "preperimetric" stage of glaucoma, are the most sensitive parameters, while PERG changes later. Both the color contrast and light PERGs reduce in glaucoma. However, a significant correlation was detected only between the reduction of the color contrast PERG and visual field defects. A reduced sensitivity of dark and color channels of the retinal cone systems was also registered. Defects of color sensitivity are more pronounced and they precede the onset of light sensitivity changes. Defects of color and contrast sensitivity are an early sign of the progressing of optic neuropathy in glaucoma.

New data on the function of the retinal cone system in glaucoma are presented, which extend the symptom complex of optic neuropathy of glaucoma origin and the potentialities of initial diagnosis of glaucoma. A new symptom is detected: disordered topography of color (red and green) sensitivity, which can serve as the early symptom of glaucomatous optic neuropathy and indicate the degree of its progress. The location of the process, detected in examination of color sensitivity topography, is more extensive than it is detected by static perimetry. Primary location of functional disorders is detected in the parafoveal area and the disorders are the more severe the further from the center during the initial stage of glaucoma. As the process progresses, the central zones are involved in it.

Visual system channels were examined in 25 patients with multiple sclerosis. A new complex of symptoms was detected, reflecting the acute stage and the chronic demyelinizing process, which includes disorders of contrast, color, and spatial contrast sensitivity and stereoscopic vision. This can be useful in differential diagnosis of optic nerve diseases and evaluation of the visual system function in multiple sclerosis and prediction of the disease course.

A new method of multifocal electroretinography making use of scanning laser ophthalmoscope with a wavelength of 630 nm (SLO-m-ERG), evoking short spatial visual stimuli on the retina, is proposed. Algorithm of presenting the visual stimuli and analysis of distribution of local electroretinograms on the surface of the retina is based on short m-sequences. Mathematical cross correlation analysis shows a three-dimensional distribution of bioelectrical activity of the retina in the central visual field. In normal subjects the cone bioelectrical activity is the maximum in the macular area (corresponding to the density of cone distribution) and absent in the blind spot. The method detects the slightest pathological changes in the retina under control of the site of stimulation and ophthalmoscopic picture of the fundus oculi. The site of the pathological process correlates with the topography of changes in bioelectrical activity of the examined retinal area in diseases of the macular area and pigmented retinitis detectable by ophthalmoscopy.

A new method for evaluating disorders in the sense of color has been developed and offered for practice. A total of 340 patients with diseases of the retina and optic nerve and 80 normal subjects were examined. The results indicate that different conditions of examination, selection of combination by the color, brightness, and deepness of the stimulus and background allow detection of decreased sensitivity of one, two, or three color perceptors (disorders in sense of color--color blindness) and permit a quantitative evaluation of functional disorders in the color channels of visual system. The new method can be used in the diagnosis of the initial pathological processes of different origin, involving the cone system at any level of visual route and associated with acquired disorders in color vision.

A new method-achromatic static campymetry-was used for the early diagnosis of visual function disorders in glaucoma. It was realized through IBM personal computer in the DOS system with SVGA monitor. The method permits examination of the functional topography of the on and off channels of the retinal cone system, in other words, it detects the early disorders of contrast sensitivity in each site of the visual field. Achromatic static campymetry revealed changes in 100% of patients with the initial primary open-angle glaucoma in whom the traditional static perimetry using Perimat 206 showed no disorders of the central and paracentral visual field in the presence of normal ophthalmic tone.

A new method for examining spatial contrast sensitivity (SCS) is described, making use of the display of an IBM-compatible computer, on which sinusoidal patterns are presented: achromatic and chromatic red, green, blue against the black background at a frequency of 0.5 to 22 cycles/degree. In health similarity of curves to the achromatic and chromatic patterns was observed, with the maximal sensitivity at spatial frequencies from 2 to 8 cycles/degree and a reduction at low and high spatial frequencies. In patients with the initial open-angle glaucoma the SCS at the high spatial frequencies was reduced for all colors with "dips" at the medium spatial frequencies in response to the blue pattern. In patients with albinism the SCS to achromatic and chromatic patterns were appreciably decreased in the entire range of spatial frequencies and absent at all in the range of high spatial frequencies. The method is recommended for investigating the channels of achromatic and chromatic spatial sensitivity, detecting the contribution of color receptors to the color contrast, and for the initial diagnosis of diseases of the retina and optic nerve.

Contrast sensitivity was examined in patients with optic neurites of different etiology. Achromatic and chromatic (red-black, green-black, and blue-black) sinusoidal patterns were presented in succession against the black background at a frequency of 1-22 cycles/degree on the monitor of an IBM computer. Contrast sensitivity was found altered during exacerbation of optic neuritis on both involved and intact eyes, this indicating a possible involvement of the chiasmal region. The authors discuss a new approach to investigation of the mechanisms of impairment of the optic nerve in optic neuritis in the presence of disseminated sclerosis and neuritis of obscure etiology.

Visual evoked potentials were analyzed and general and local electroretinography carried out in 83 children and adolescents (145 eyes) aged 7 to 16 with different ocular diseases. The latencies of P100 component of evoked potentials reliably varied in different clinical groups. The role of electrophysiological studies in the differential diagnosis of pathological processes of different localization is shown, as is the role of time characteristics of evoked potentials in discrimination between the functional and organic disorders in the ocular system.

Absence of early signs specific for thallium intoxication requires objective diagnostic methods. The studies covered 4 techniques: electroretinography (ERG), assessment of urine levels of thallium and delta-aminolevulinic acid, capillaroscopy. The authors supported their previous foundation concerning diagnostic value of ERG for early diagnosis of thallium effects (higher amplitude of b-wave in one and that of a-wave in 8 out of 10 examinees). Further experimental and clinical basis for grading the intoxication through amounts of urinary thallium were found promising. Capillaroscopy method appeared informative: 8 out of 12 examinees demonstrated spastic and atonic state of hand capillaries--that provided objective verification of vascular disorders in workers exposed to thallium and its derivatives.

A total of 45 patients (90 eyes) with stages I and II open-angle glaucoma (OAG) were examined, 26 of these were administered lipoic acid in a daily dose of 0.075 g for 2 months and 19 were given 0.15 g daily for 1 month. Control group consisted of 31 patients with OAG who were administered only local hypotensive therapy. Vision acuity and visual field were checked up, tonometry, tonography, and campimetry carried out, and levels of nonprotein SH-groups and activity of gamma-glutamyl transpeptidase measured in the lacrimal fluid. Improvement of the biochemical parameters, visual function, and of the coefficient of efficacy of liquid discharge was more expressed in the patients administered lipoic acid in a daily dose of 0.15 g. Color campimetry results indicate improved sensitivity of the visual analyzer under the effect of treatment. Improvement was attained in approximately 45-47.5% of examined eyes, and was more often seen in patients with stage II OAG: in 57-58% eyes. The effect of lipoic acid may be explained by its antioxidant properties and direct influence on ocular tissue metabolism.

Visual functions in albinism were examined by psychophysiological and electrophysiological methods. Impaired functioning of light, brightness, and contrast channels of the visual system was revealed, as well as specific electrophysiological parameters typical of this condition: increased wave a and shortened latent periods of waves a and b on the total ERG, reduced amplitude and a shorter latent period of P-100 peak of visual evoked potential, prolonged latent periods of waves a and b of local ERG, and increased amplitude of waves a and b of L-ERG.

Color campimetry was realized with the use of an IBM-compatible computer display with a program permitting the registration of brightness sensitivity thresholds and the time of sensorimotor reaction to visual stimuli offered on the display in each point of the visual field. Investigation of light and color sensitivity thresholds and of the time of sensorimotor reaction to stimuli of different spectral composition in normal subjects helped study the functional topography of the retina by the time of sensorimotor reaction and by the brightness sensitivity thresholds. The methods of equalization by the brightness of the stimulus and background by means of recording the time of sensorimotor reaction was tried in experiments with different background brightness and stimulus size and in ophthalmologic examinations of patients with color abnormalities, diseases of the retina and optic nerve, with glaucoma and albinism.

The authors present the first results of examining the vision system with the use of an automated programmed complex realized in the 'C' program language in the IBM and Dos operation system, that helped present in a chart the distribution of the ocular light sensitivity and time of the sensomotor reaction in every site of the visual field of 40-50 degrees. The results evidence that computer-aided methods may be effectively used to assess the light sensitivity of the eye, contrast sensitivity, space summation, rod and cone interactions, the topography of color photoreceptors, and the function of the posterior section of the eye in abnormalities of the retina and the optic nerve, as well as to monitor visual function rehabilitation after treatment.

Total and local electroretinograms were studied simultaneously with registration of visual evoked potentials in 174 patients with nystagmus without pathologic shifts in the anterior section of the eyeball. Clinical and electrophysiologic findings permitting dividing the patients with nystagmus into two groups with different prognosis of the disease course: that without apparent changes in the fundus oculi with normal and subnormal parameters of the total and local ERG and that with pathologic changes in the retina and optic nerve and the corresponding electrophysiologic symptoms. Central mechanisms of nystagmus origin may be supposed in Group 1; visual function improved after pleoptic treatment. In Group 2 sensory mechanisms of nystagmus development are possible; visual functions did not improve after therapy. The mechanisms of vision deterioration in nystagmus are to be studied.

Electroretinography (ERG) was used to assess the functions of the retinal central and peripheral sections in patients with cataracts of various origins and different degrees of opacities; the method is based on the use of 18-20 degrees red saturating stimulus fit in sucker electrode for macular ERG and Hanz-Feld white stimulus for total ERG. Macular biopotential recorded in the patients with mature cataracts without pathologic changes in the macular region coincided with the mean values of local macular ERG recorded in transparent ocular media with medium-intensity stimuli. Macular biopotentials in cataracts significantly differed from the normal values in dystrophic changes of the macular area. Total ERG values in transparent ocular media and in mature cataract patients coincided only in with saturating white stimulus in cases when no retinal abnormalities were present. ERG with weak and medium-intensity stimulating light has shown has shown a significant difference of ERG parameters in these patient populations. Analysis of ERG findings in 375 patients with cataracts of various origins and with various opacity degrees has shown the possibility of extrapolating the data on ERG symptoms of retinal abnormalities known in transparent ocular media to the diagnosis of the pathologic processes in the retina when the fundus of the eye cannot be seen; this method will be useful in predicting visual functions in the postoperative period.

We used a suction electrode with a frosted front window to record a full-field (general) ERG, and a suction electrode with a short-focus lens and a red-green light diode to record a local ERG. As the suction electrode moved with the eye, the stimulus struck the macula in all positions of gaze. Our data showed that only mildly intense stimuli with an angular size of 10 to 15 degrees induced a retinal response, with a macular contribution of 70%. Patients with various dystrophic changes of the retina, such as Stargardt's dystrophy, vitelliform dystrophy of the Best type, X-linked juvenile retinoschisis, and age-related macular dystrophy of different stages, were examined. In patients with retinitis pigmentosa, the cones were involved in the pathologic process to varying degrees; the behavior of the local ERGs helped determine the final visual acuity. We also observed a reduction in the local ERG in patients with Stargardt's dystrophy that disappeared as the disease progressed. In age-related macular dystrophy, a disturbance of the electrogenesis mainly occurred in the central retina in advanced stages of the disease.

Appearance of dystrophic alterations in the retina was carried out by administering 0.2 ml 12 mM of tallium chloride solution into the vitreous humour of 9 rabbits. Electroretinographic examination revealed a decline in the b wave either decreasing 2-3 times or entirely disappearing as early as on day 2 after the administration of tallium chloride. Electron microscopic investigation suggested that photoreceptors of the retina were initial by involved in the pathological process. Namely, the external segments of the photoreceptors were found to be reduced, indicating impairment of the formation of photoreceptor disks, which is known to proceed continuously under normal conditions. In the absence of an electroretinogram (ERG), the photoreceptor layers were shown to have disappeared completely. An examination of 28 subjects who were exposed to tallium and its compound at work revealed impaired retinal electrogenesis, as evident from subnormal ERG responses. This was of a functional nature and became more pronounced as occupational exposure time increased. The fact that the internal retinal layers and the 3-rd neurone remained intact, as suggested by the electrical sensitivity of the eye and lability of the optic nerve as well as by static perimetry, correlated with the EM findings obtained in experiments. Ophthalmobiomicroscopic examination of 12 eyes yielded data on characteristic changes in the lens when visual functions remained intact. These findings suggest that changes in the ERG may be indicative of initial preclinical symptoms of tallium intoxication and as such can be used when persons exposed to it in industry receive check-ups.

Two methods for recording the retinal local biopotential with the gaze fixation control and without this control are described, to be used for the assessment of the status of any retinal or macular site, among other things. A ring-shaped sucker electrode is employed in both methods; this electrode is supplied with a transparent anterior window and infrared-illuminated mirror in one method and in the other the electrode incorporates a light-emitting diode and an optic system that helps create a 6-20 degrees stimulus. Theoretical analysis and experimental findings evidence that the minimal area on the retina from which a local response may be obtained, fit for clinical purposes, conforms to 10-15 degrees with a stimulus 5 times brighter than semisaturating brightness. The local response share in this case is 70% and the number of possible blendings 50. The results explaining the choice of the conditions for the retinal local biopotential recording are presented. The suggested methods help assess the function of the macular area, distinguish between the functions of the cone and rod systems, record the total and Hanz-Feld electroretinograms without electrode substitution, record the macular biopotential in babies and in patients with nystagmus or with cataracts of various origins.