Association between Asymptomatic Unilateral Internal Carotid Artery Stenosis and Electrophysiological Function of the Retina and Optic Nerve

Purpose. This study was designed to assess retinal and optic nerve bioelectrical function in patients with unilateral asymptomatic but hemodynamically significant internal carotid artery stenosis (ICAS). Methods. Forty-two subjects with a diagnosis of unilateral ICAS and 34 controls were analyzed. Full-field electroretinogram (ERG), pattern electroretinogram (PERG), and pattern visual-evoked potentials, as well as optical coherence tomography and ophthalmological examination, were performed. Data analysis included eyes ipsilateral to ICAS (EIS) and eyes contralateral to ICAS (ECS). Results. Intraocular pressure was significantly decreased in EIS and ECS compared to that in the controls. In the macula, both the cube average thickness and cube volume values were significantly reduced both in EIS and ECS compared to those in the controls. Similarly, PERG P50 and N95 wave amplitudes were significantly smaller in EIS and ECS compared to those in the controls. The ERG rod b-wave and rod-cone a-wave amplitudes were decreased, and implicit times were significantly prolonged, whereas the OP wave index was reduced in EIS compared to that in the controls. No differences in IOP, OCT, or ERG and PERG parameters were identified between EIS and ECS. Conclusions. Our study demonstrated that retinal bioelectrical function is negatively affected by ICAS despite the absence of objective clinical signs and symptoms of ocular ischemia

Pattern electroretinography and photopic negative response in glaucoma diagnostics

Celem niniejszego artykułu jest przedstawienie danych z najnowszej literatury i doświadczeń własnych dotyczących roli elektroretinogramu stymulowanego wzorcem (PERG) oraz fotopowej negatywnej odpowiedzi (PhNR) w diagnostyce jaskry. Wyniki tych badań wykazują, że redukcja amplitudy PERG jest wskaźnikiem konwersji do pełnoobjawowej jaskry i przyspieszonej progresji ścieńczenia włókien nerwowych siatkówki u pacjentów z podejrzeniem jaskry. Za pomocą PERG i PhNR można wykryć zaburzenia funkcji siatkówki w jaskrze w momencie, gdy wyniki rutynowych badań diagnostycznych są niemiarodajne bądź mieszczą się w granicach normy. PERG i PhNR stanowią dowód na odwracalność dysfunkcji komórek zwojowych siatkówki. Badania te mogą służyć także jako wskaźnik dobrze dobranego leczenia obniżającego ciśnienie wewnątrzgałkowe (CWG). Przy podejrzeniu jaskry normociśnieniowej PERG może być jedynym wskaźnikiem zaburzenia funkcji komórek zwojowych siatkówki i stanowić podstawę włączenia leczenia obniżającego CWG.The aim of this article is to present data from recent literature and our own experience with respect to the role of pattern electroretinography (PERG) and photopic negative response (PhNR) in glaucoma diagnosis. The results of these studies show that PERG amplitude reduction is an indicator of conversion to manifest glaucoma and a predictor of increased rate of progression of retinal nerve fiber layer (RNFL) thinning in patients with glaucoma suspicion. PERG and PhNR are capable of detecting decreased retinal function when the results of routine diagnostic examinations are still within normal ranges or borderline. PERG and PhNR may also serve to confirm retinal function improvement. Both tests may also serve as an indicator of well-selected IOP-lowering therapy. In patients suspected of normal-tension glaucoma, PERG may be the only indicator of RGCs dysfunction and may be the diagnostic basis for the inclusion of IOP-lowering therapy