Sequential morphological and functional features of retinal damage in mice exposed to different doses (40 vs. 20 mg/kg) of sodium iodate (NaIO3) were analyzed. Retinal morphology, apoptosis (TUNEL assay), and function (electroretinography; ERG) were examined at several time points after NaIO3 administration. The higher dose of NaIO3 caused progressive degeneration of the whole retinal area and total suppression of scotopic and photopic ERG. In contrast, the lower dose induced much less severe degeneration in peripheral part of retina along with a moderate decline of b- and a-wave amplitudes in ERG, corroborating the presence of regions within retina that retain their function. The peak of photoreceptor apoptosis was found on the 3rd day, but the lower dose induced more intense reaction within the central retina than in its peripheral region. In conclusion, these results indicate that peripheral area of the retina reveals better resistance to NaIO3 injury than its central part.

Alzheimer’s disease (AD) is one of the most common causes of dementia in the world. Patients with AD frequently complain of vision disturbances that do not manifest as changes in routine ophthalmological examination findings. The main causes of these disturbances are neuropathological changes in the visual cortex, although abnormalities in the retina and optic nerve cannot be excluded. Pattern electroretinogram (PERG) and pattern visual evoked potential (PVEP) tests are commonly used in ophthalmology to estimate bioelectrical function of the retina and optic nerve. The aim of this study was to determine whether retinal and optic nerve function, measured by PERG and PVEP tests, is changed in individuals in the early stages of AD with normal routine ophthalmological examination results. Standard PERG and PVEP tests were performed in 30 eyes of 30 patients with the early stages of AD. The results were compared to 30 eyes of 30 normal healthy controls. PERG and PVEP tests were recorded in accordance with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. Additionally, neural conduction was measured using retinocortical time (RCT)—the difference between P100-wave latency in PVEP and P50-wave implicit time in PERG. In PERG test, PVEP test, and RCT, statistically significant changes were detected. In PERG examination, increased implicit time of P50-wave (P < 0.03) and amplitudes reductions in P50- and N95-waves (P < 0.0001) were observed. In PVEP examination, increased latency of P100-wave (P < 0.0001) was found. A significant increase in RCT (P < 0.0001) was observed. The most prevalent features were amplitude reduction in N95-wave and increased latency of P100-wave which were seen in 56.7% (17/30) of the AD eyes. In patients with the early stages of AD and normal routine ophthalmological examination results, dysfunction of the retinal ganglion cells as well as of the optic nerve is present, as detected by PERG and PVEP tests. These dysfunctions, at least partially, explain the cause of visual disturbances observed in patients with the early stages of AD.

Speed of Visual Sensorimotor Processes and Conductivity of Visual Pathway in Volleyball Players Volleyball is a dynamic game which requires a high level of visual skills. The first aim of this study was to investigate the several aspects of reaction times (RT) to visual stimuli in volleyball players (12) compared to non-athletic subjects (12). By using the tests included in the Vienna Test System (Schuhfried, Austria), simple reaction time (SRT), choice reaction time (CRT) and peripheral reaction time (PRT) were examined. The second aim of this study was to assess the neurophysiological basis of early visual sensory processing in both examined groups. We measured two sets of pattern-reversal visual evoked potentials (VEPs) during monocular central field stimulation (Reti Scan, Roland Consult, Germany). The latencies of waves N75, P100 and N135 were determined. We observed significantly shorter (p<0.05) total reaction time to stimuli appearing in the central and peripheral field of vision in the volleyball players compared to non-athletes. With regard to SRT and CRT the main differences between the groups appeared in pre-motor reaction times. Volleyball players had shorter VEPs P100 wave latencies (p<0.05) than the non-athlete group. The results indicate faster signal transmission in visual pathways in athletes than in non-athletes. This fact can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system.

Purpose To determine bioelectrical function and structural changes of the retina in patients with early stages of Parkinson’s disease (PD).Materials and methodsThirty-eight eyes of 20 patients with early idiopathic PD and 38 eyes of 20 healthy age- and sex-matched controls were ophthalmologically examined, including assessment of distance best-corrected visual acuity (DBCVA), slit lamp examination of the anterior and posterior segment of the eye, evaluation of the eye structures: paramacular retinal thickness (RT) and retinal nerve fiber layer (RNFL) thickness with the aid of OCT, and the bioelectrical function by full-field electroretinogram (ERG). Additionally, PD patients were interviewed as to the presence of dopamine-dependent visual functions abnormalities.ResultsIn patients with early PD, statistically significant changes in comparison with the control group were observed in ERG. They contained a reduction in mean amplitudes of the scotopic a-wave (rod–cone response), the scotopic oscillatory potentials (OPs)—OP2 and OP3, the photopic b-wave, and a reduction in the overall index (OP1 + OP2 + OP3) and a prolongation of mean peak times of the scotopic OP1, OP2, OP3, OP4 (p < 0.05). A questionnaire concerning abnormalities of dopamine-dependent visual functions revealed that PD patients with abnormal peak times of OP1, OP2, and OP3 reported non-specific visual disturbances more frequently in comparison with PD patients with normal peak times of OPs. Other analyzed parameters of ERG, DBCVA, RT, and RNFL did not significantly differ between patients with PD and the control group.ConclusionIn patients with early PD, bioelectrical dysfunction of the retina was observed in the ERG test, probably as a result of dopamine deficiency in the retina. The results of our study indicate that ERG may also be a useful tool for understanding the reason for non-specific visual disturbances occurring in PD patients.

BackgroundThe aim of this study was to determine the type and frequency of ophthalmologic changes occurring in patients with Parkinson disease (PD).Material/MethodsOne hundred consecutive patients (196 eyes) with idiopathic PD and a control group consisting of 100 healthy patients (196 eyes) matched for age and sex underwent a complete ophthalmological examination of both eyes, including assessment of patient medical history, dry eye questionare, and visual hallucinations questionnaire, distance and near best corrected visual acuity (DBCVA, NBCVA), color vision, distance photopic contrast sensitivity, near point of convergence, slit lamp examination of the eye anterior segment, tear film osmolarity and breakup time, aqueous tear production, and intraocular pressure, as well as fundus examination and evaluation of the perimacular retinal thickness (RT) and peripapillary retinal nerve fiber layer (RNFL) thickness.ResultsIn the eyes of PD patients DBCVA, NBCVA, contrast sensitivity, and color discrimination were significantly reduced. We also detected increased frequency of convergence insufficiency, seborrhoic blepharitis, meibomian gland disease (MGD), dry eye syndrome, nuclear and posterior subcapsular cataract, and glaucoma (p<0.05). However, intraocular pressure (IOP) was significantly lower in the PD group compared to controls. The frequency of visual hallucinations, age-related macular degeneration (ARMD), and other ophthalmological diseases, as well as RT and RNFL thickness, did not significantly differ between investigated groups.ConclusionsClinicians need to be aware of the association between PD and ophthalmological changes. Restoration of good-quality vision has a great impact on PD patients’ quality of life, reduction of costs of treatment and care, and rehabilitation.