Neurodegenerative Process Linking the Eye and the Brain.

Recent literature agrees that neurodegenerative processes involve both the retina and the central nervous system, which are two strictly related anatomical structures. However, the causal mechanisms of this dual involvement are still uncertain. To date, anterograde transsynaptic neurodegeneration, triggered by retinal ganglion cells' death, and retrograde transsynaptic neurodegeneration, induced by neurodegenerative processes of the central nervous system, has been considered the major possible causal mechanisms. The development of novel neuroimaging techniques has recently supported both the study of the central stations of the visual pathway as well as the study of the retina which is possibly an open window to the central nervous system.

Assessment of the retinal posterior pole in dominant optic atrophy by spectral-domain optical coherence tomography and microperimetry.

BACKGROUND: To assess posterior pole (PP) retinal structure in patients with genetically confirmed autosomal dominant optic atrophy (ADOA) using new spectral domain optical coherence tomography (SD-OCT) segmentation technology. To analyze retinal PP thickness in relation to retinal sensitivity data from microperimetry (MP) in ADOA patients. METHODS AND FINDINGS: This prospective cross-sectional study included 11 patients with ADOA and 11 age-matched healthy subjects. All participants underwent both a "Posterior Pole" and "peripapillary RNFL (pRNFL)" scanning protocol using SD-OCT. Functional mapping of the PP was also performed using MP. A customized program was implemented in order to achieve accurate superimposition of MP sensitivity map onto SD-OCT map. The thickness of the PP different retinal layers and pRNFL was obtained and measured for each eye. Mean retinal sensitivity values and fixation stability were obtained and compared between ADOA patients and healthy subjects. Correlation analysis was performed on a point-to-point basis to evaluate the association between mean thickness and retinal sensitivity of each retinal layer. Total retinal thickness (TRT), Retinal Nerve Fiber Layer (RNFL), Ganglion Cell Layer (GCL), Inner Plexiform Layer (IPL), Inner Nuclear Layer (INL) and Inner Retinal Layers (IRL) at the posterior pole as well as pRNFL were significantly thinner in ADOA patients (P < 0.0001). On the contrary, the Outer Plexiform Layer (OPL) and the Outer Nuclear Layer (ONL) were significantly thicker in the ADOA group (P < 0.001). No significant differences were found in Retinal Pigment Epithelium (RPE) and Outer Retinal Layers (ORL) thickness between ADOA and controls. The average PP retinal sensitivity was significantly reduced in ADOA patients compared with controls (P < 0.001), as measured by microperimeter Nidek MP-1 (MP1). Fixation stability was significantly worse in the ADOA group (P = 0.01). The most severe sensitivity defects in ADOA patients were found at the level of the papillo-macular bundle (PMB). CONCLUSIONS: Inner retinal layers showed pathological changes in ADOA patients. In addition, the whole retinal PP (not only the PMB) was significantly altered in ADOA, both in terms of retinal thickness and sensitivity.

Inferior retinotomy and silicone oil tamponade for recurrent inferior retinal detachment and grade C PVR in eyes previously treated with pars plana vitrectomy or scleral buckle.

BACKGROUND: One of the most challenging problems in vitro-retinal surgery is the recurrence of retinal detachment in the context of high-grade proliferative vitreoretinopathy (PVR). The aim of our retrospective study was to assess the surgical outcomes of pars plana vitrectomy, 180° inferior retinotomy and silicone oil tamponade combined with phacoemulsification and IOL implantation for recurrent inferior retinal detachment with grade C PVR in phakic eyes. The study was carried out at tertiary referral centre - University Hospital of Rome "Tor Vergata". METHODS: Retrospective analysis of 33 eyes affected by recurrent inferior retinal detachment and grade C PVR after primary encircle scleral buckling (SB group - 12 eyes), or pars plana vitrectomy (PPV group - 21 eyes). All patients subsequently underwent PPV and silicone oil tamponade at our Institution. The first outcome measure was retinal reattachment, and second outcomes were reoperation rates, best-corrected visual acuity (BCVA) and postoperative complications. RESULTS: All patients in the SB group and 19 (90%) patients of the PPV group achieved retinal reattachment. Final BCVA was better in the SB group (p = 0.045). Two eyes in the PPV group required a third vitrectomy with heavy silicone oil tamponade. Postoperative complications included silicone oil in a deep anterior chamber (3 eyes in each group), untreatable hypotony in 1 eye in the PPV group (that led to enucleation due to phthisis bulbi), and elevated intraocular pressure in 3 patients (2 eyes in the PPV group). CONCLUSIONS: Phacoemulsification with IOL implant, PPV with silicone oil tamponade associated with 180° inferior retinotomy may lead to better anatomical success in patients who have previously undergone SB procedure for inferior retinal detachment repair compared with eyes that underwent a primary PPV.

Visual disability and quality of life in glaucoma patients.

Glaucoma is an optic neuropathy that can result in progressive and irreversible vision loss, thereby affecting quality of life (QoL) of patients. Several studies have shown a strong correlation between visual field damage and visual disability in patients with glaucoma, even in the early stages of the disease. Visual impairment due to glaucoma affects normal daily activities required for independent living, such as driving, walking, and reading. There is no generally accepted instrument for assessing quality of life in glaucoma patients; different factors involved in visual disability from the disease are difficult to quantify and not easily standardized. This chapter summarizes recent works from clinical and epidemiological studies, which describe how glaucoma affects the performance of important vision-related activities and QoL.

Association Between Alzheimer's Disease and Glaucoma: A Study Based on Heidelberg Retinal Tomography and Frequency Doubling Technology Perimetry.

AIM: To assess the frequency of glaucoma-like alterations in Alzheimer's disease (AD) patients using Heidelberg Retinal Tomograph III (HRT-3) and Frequency Doubling Technology (FDT) perimetry. METHODS: The study included 51 eyes of 51 AD subjects and 67 eyes of 67 age- and sex-matched controls. Subjects underwent an ophthalmological examination including measurements of intraocular pressure (IOP), Matrix FDT visual field testing, optic nerve head morphology and retinal nerve fiber layer thickness (RNFLt) assessment by slit-lamp biomicroscopy and HRT-3. RESULTS: The frequency of alterations was significantly higher in the AD group (27.5 vs. 7.5%; p = 0.003; OR = 4.69). AD patients showed lower IOP (p = 0.000) despite not significantly different values of central corneal thickness (CCT) between the groups (p = 0.336). Of all the stereometric parameters measured by HRT-3, RNFLt was significantly lower in AD patients (p = 0.013). This group also had significantly worse results in terms of Moorfields Regression Analysis (p = 0.027). Matrix showed significantly worse Mean Deviation (MD) (p = 0.000) and Pattern Standard Deviation (PSD) (p = 0.000) values and more altered Glaucoma Hemifield Test (p = 0.006) in AD patients. Pearson's R correlation test showed that Mini Mental State Examination is directly correlated with MD (R = 0.349; p = 0.034) and inversely correlated with PSD (R = -0.357; p = 0.030). CONCLUSION: Patients with AD have a higher frequency of glaucoma-like alterations, as detected by the use of HRT-3. These alterations were not associated with elevated IOP or abnormal CCT values.

Evaluation of eye movements pattern during reading process in patients with glaucoma: a microperimeter study.

PURPOSE: To assess eye movements pattern during reading process in patients with primary open-angle glaucoma (POAG) using a microperimeter. METHODS: Thirty-two patients with POAG at early and moderate stage, according to Glaucoma Staging System 2, and 34 healthy age- and sex-matched subjects were included in the study. Reading speed and accuracy were previously evaluated with specific tests adjusted for age. In addition, all participants performed a reading test with Microperimeter Nidek MP1. Ocular movements during the reading process were recorded and values of maximum and minimum eye movements along the horizontal (Xmax and Xmin) and vertical (Ymax and Ymin) axis and mean ocular movement speed were provided by the MP1. RESULTS: There were significant differences between patients with and without POAG in terms of Xmax and Ymax eye movement values (4.75 ± 2.57 versus 3.38 ± 0.67, p = 0.003; and 4.39 ± 1.43 versus 3.34 ± 0.52, p<0.001, respectively). These differences were significant even comparing only stage 1 patients to controls. There were no significant differences in Xmin and Ymin values and mean ocular movement speed between the 2 groups. CONCLUSIONS: The study showed significant differences in eye movements pattern in patients with POAG during the reading test performed with the MP1 when compared to the control group. These alterations may be partly the consequence of the neurodegenerative process of the central visual pathway in glaucoma.

Increased malondialdehyde concentration and reduced total antioxidant capacity in aqueous humor and blood samples from patients with glaucoma.

PURPOSE: To evaluate the levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) in the blood and aqueous humor of glaucomatous and nonglaucomatous patients. To measure the adenosine triphosphate/adenosine diphosphate/adenosine monophosphate (ATP/ADP/AMP) concentration as a biomarker of the blood energy charge potential. METHODS: We examined 40 consecutive patients with primary open-angle glaucoma scheduled for cataract surgery. Twenty-six age-matched subjects scheduled for cataract surgery were enrolled as a control group. Blood and aqueous humor samples were collected at the time of surgery. MDA concentrations and blood nucleotides were measured with high-performance liquid chromatography. The TAC of the samples was estimated with the oxygen-radical absorbance capacity method. RESULTS: Blood and aqueous humor MDA levels in glaucoma patients (respectively, 0.976±0.370 and 0.145±0.065 µmol/ml) were significantly increased (p<0.001 for both) over those of the control group (respectively, 0.454±0.395 and 0.060±0.039 µmol/ml). In contrast, the control group presented significantly higher TACs than did the glaucoma group in both the blood (control: 2.681±1.101 and glaucoma: 1.617±0.674 µmol Trolox Equi/g; p<0.001) and aqueous humor (control: 0.963±0.302 and glaucoma: 0.788±0.346 µmol Trolox Equi/g; p=0.039). The control group (0.869±0.037) exhibited statistically significant (p<0.001) higher values of blood adenosine triphosphate/adenosine diphosphate (ATP-ADP) levels than did the glaucoma group (0.791±0.037). CONCLUSIONS: Our data further support the hypothesis that oxidative stress and decreased antioxidant defenses are involved in glaucoma. High-performance liquid chromatography appears to be an effective and sensitive method to detect altered levels of oxidative stress markers in glaucoma patients.

Anatomical and functional results of macular hole retinal detachment surgery in patients with high myopia and posterior staphyloma treated with perfluoropropane gas or silicone oil.

PURPOSE: To evaluate the use of perfluoropropane gas (C3F8) versus silicone oil (SO) for retinal detachment secondary to macular hole in patients with high myopia and posterior staphyloma. METHODS: In a retrospective study, 30 eyes of 30 patients underwent pars plana vitrectomy, and C3F8 (17 patients) or SO (13 patients) tamponade; internal limiting membrane peeling was performed successfully at the first surgery in 23 patients. High-density silicone oil tamponade was used for reoperations. RESULTS: The mean values of patients' characteristics were as follows: age, 57.7 years; axial length, 29.02 mm; spherical equivalent refraction, -15.40 diopters; initial best-corrected visual acuity, 2.35 logarithm of the minimum angle of resolution; final best-corrected visual acuity, 1.59 logarithm of the minimum angle of resolution. In C3F8 group, best-corrected visual acuity significantly improved (P < 0.001), passing from 2.34 to 1.36 logarithm of the minimum angle of resolution. Vision improvement from blindness to low vision was significantly greater (P = 0.009) in C3F8 group (16 of 17; 94%) than in SO group (6 of 13; 46%). A significant higher initial success (P = 0.025) was found in the C3F8 group (16 of 17; 94%) than in the SO group (7 of 13; 54%). Proliferative vitreoretinopathy was the cause of initial failure; all these subjects achieved anatomical success after being reoperated with high-density silicone oil tamponade. CONCLUSION: C3F8 and internal limiting membrane peeling could represent the most effective strategy in highly myopic patients with macular hole retinal detachment. Other tamponade agents must be investigated.