Pasquale Plateroti

Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma: A Review of the Literature with Updates on Surgical Management

Pseudoexfoliation syndrome (PES) is a systemic disorder caused by progressive accumulation of extracellular material over various tissues. PES usually determines increased intraocular pressure, changes in the anatomical aspects of the optic nerve, and visual field alterations leading to the diagnosis of pseudoexfoliation glaucoma (PEG). Use of topical medical treatment usually leads to poor results in terms of long-term follow-up but many surgical techniques, such as Argon Laser or Selective Laser Trabeculoplasty, have been proposed for the management of PEG affected patients. The present paper is a review on the pseudoexfoliation syndrome and pseudoexfoliation glaucoma with an update on surgical management.

Potential regulatory molecules in the human trabecular meshwork of patients with glaucoma: Immunohistochemical profile of a number of inflammatory cytokines

Glaucoma occurs when there are imbalances between the production and the drainage of the eye liquid. The vast majority of the aqueous humor leaves the eye through the trabecular meshwork (TM). The cause of hypertonicity may be due to an alteration in the thickness of the TM. In the majority of cases the molecular changes that determine primary open‑angle glaucoma (POAG) are unclear. However, it has been hypothesized that the significant increase in the extracellular matrix (ECM) of the fibrillary bands in the TM is associated with possible inflammatory conditions. In this study the tissue distribution of interleukin (IL)‑6, IL‑1β, transforming growth factor-β1 (TGF‑β1), vascular endothelial growth factor (VEGF) and tumor necrosis factor α (TNF‑α) was analyzed in TM samples from patients with POAG by immunohistochemistry. Seven specimens from patients with POAG and three control tissues were analyzed by immunohistochemistry using specific antibodies against these cytokines. Morphological changes in the TM, such as increased cell content, macrophages, fibrosis and accumulation of neutrophils, were observed by transmission electron microscopy. In human TM tissues, an evident immunoreactivity for IL‑6, IL‑1β and TNF‑α was observed in patients with POAG when compared with the control subjects, indicating that these cytokines may be correlated with disease activity. TM endothelial cells secrete a number of factors and cytokines that modulate the functions of the cells and the ECM of the conventional outflow pathway. In the TM in glaucoma, macrophages produce cytokines, including IL‑6, IL‑1β and TNF‑α, leading to an acute inflammatory response and recruitment of other immune cells, including T lymphocytes. In addition, TGF‑β1 regulates and induces the expression of IL‑6 in TM that indirectly induces angiogenesis by stimulating VEGF expression. The present results support previous evidence that suggests that growth factors and cytokines can induce ECM remodelling and alter cytoskeletal interactions in the TM.

Abnormalities of retinal ganglion cell complex at optical coherence tomography in patients with type 2 diabetes: a sign of diabetic polyneuropathy, not retinopathy

AIMS To compare optical coherence tomography (OCT)-derived neuro-retinal parameters in patients with type 2 diabetes and non-diabetic controls and to evaluate their correlation with diabetic retinopathy (DR) and polyneuropathy (DPN). METHODS One-hundred consecutive patients with type 2 diabetes were examined by spectral-domain (SD) OCT for evaluating ganglion cell complex (GCC) and retinal nerve fibre layer (RNFL) thickness and two new pattern-based quantitative measures of GCC damage, global and focal loss volume (GLV and FLV). Fifty sex- and age-matched non-diabetic subjects served as control. RESULTS RNFL thickness (101.0±10.6 vs. 106.4±10.3 μm, P=0.003) was significantly lower and GLV (6.58±4.98 vs. 4.52±3.10 %, P=0.008) and FLV (1.90±1.97 vs. 0.89±0.84 %, P<0.0001) were significantly higher in diabetic versus control subjects. The OCT parameters did not differ significantly according to DR grade. Conversely, RNFL thickness was lower and GLV and FLV were higher in patients with versus those without DPN, and the extent of changes increased significantly with quartiles of DPN score. At both bivariate and multivariate analysis, OCT parameters, especially FLV, correlated significantly with DPN measures. CONCLUSIONS The GCC is significantly affected in patients with type 2 diabetes and SD-OCT might represent a useful tool to detect DPN, but not DR in these individuals.

Retinitis pigmentosa: evaluation of the vestibular system with cervical and ocular vestibular evoked myogenic potentials and the video head impulse test.

Objective Retinitis pigmentosa (RP) represents a group of inherited disorders in which abnormalities of the photoreceptors lead to progressive visual loss. Night blindness, peripheral visual field loss, and eventual total blindness represent typical visual damage of such disease. No study has previously evaluated the presence of a “latent” vestibular deficit in patients with RP. Study Design Prospective study with caloric test, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT). Setting Tertiary referral center. Patients 16 patients suffering from RP. Intervention Evaluation of vestibular dysfunction with caloric test, C-VEMPs, O-VEMPs, and the measurement of the vestibular-ocular reflex (VOR) using the v-HIT. Results Only five patients with RP showed normal values in all the vestibular tests performed. Three patients had an evident deficit at the caloric test, whereas eight (50%) of them had a normal caloric test but a pathological response in at least one of the other vestibular tests performed. No patient of the study showed a bilateral otolith or ampullary dysfunction. Conclusion Our patients with RP unexpectedly showed pathological responses in at least one of the vestibular tests performed. Nowadays, in patients affected by RP, a vestibular diagnostic protocol must include VEMPs and v-HIT to confirm the vestibular damage and to identify selective damage of the vestibular nerve.

Accidental intralenticular dexamethasone intravitreal implant with the resolution of macular oedema in central retinal vein occlusion

from a minimum of 3 years to a maximum of 17 years (median 5 years). A similar benefit of PLP has been reported in a study in which RRD developed in 2.9% eyes which underwent PLP in contrast to 24.1% eyes that did not (Uhumwangho & Jalali 2014). Lack of a control group and selection bias due to the hospital setting are the major limitations of our study. Due to retrospective nature of the study, we cannot predict the incidence of RRD. We recommend PLP for FC as in our cohort of over 300 eyes this simple prophylactic procedure helped in maintaining vision with a very low rate of development of RRD. Further randomized prospective longterm studies may provide more evidence to support our recommendation.

Twelve-Month Results of a Single or Multiple Dexamethasone Intravitreal Implant for Macular Edema following Uncomplicated Phacoemulsification

The clinical efficacy of one or two intravitreal injections of a continued deliverance dexamethasone 700 μg implant in ten patients with persistent macular edema following uncomplicated phacoemulsification was evaluated. Complete ophthalmological examination and spectral domain optical coherence tomography were carried out. Follow-up was at day 7 and months 1, 2, 4, 6, 8, and 12. At baseline mean best corrected visual acuity was 62 Early Treatment Diabetic Retinopathy Study Chart letters, which showed statistically significant improvement at each follow-up, except at month 6, to reach 79 letters at month 12 (P = 0.018). Prior to treatment mean central foveal thickness was 622 μm, which showed statistically significant improvement at each follow-up to reach a mean value of 282 μm (P = 0.012) at month 12. Five patients received a second dexamethasone implant at month 7. Two patients were excluded from the study at months 4 and 8. Intraocular pressure remained stable during the study period with the exception of mild increase in two patients requiring topical therapy. In conclusion there was statistically significant improvement of best corrected visual acuity and mean central foveal thickness with one or two intravitreal dexamethasone implants over 12 months.

Histological findings in a failed corneal riboflavin-UVA collagen cross-linking performed for progressive keratoconus.

Purpose: To report the histological and immunohistochemical findings in a cornea removed from a patient who had undergone collagen cross-linking (CXL) with riboflavin and ultraviolet-A for progressive keratoconus. CXL was performed following the Siena protocol. Two years post-CXL, a visual acuity impairment in the treated eye secondary to corneal stromal opacity had occurred, together with corneal thinning and flattening. Methods: The excised cornea was formalin-fixed, paraffin-embedded, and examined microscopically. Deparaffinized 4-&mgr;m sections were stained with hematoxylin–eosin and Masson trichrome. Further tissue sections were subjected to immunohistochemical evaluation of CD34 and Ki-67 antigens. Results: Histologically, there was no scar tissue in the failed cornea. The biomicroscopic stromal opacity corresponded microscopically to an acellular area, devoid of keratocytes, and to compaction of the lamellar collagen. Amorphous, weakly eosinophilic interlamellar deposits, extending from the anterior to the posterior two thirds of the stroma, were noted. Conclusions: CXL is a promising procedure for the treatment of progressive keratoconus with minimal reported side effects. In the present case, we speculate that the short corneal soaking time (15 minutes according to the Siena protocol) may have resulted in inefficient ultraviolet-A blocking, thermal injury, and deeper keratocyte death. Inadequate keratocyte stem cells reservoir could also play a role in individual cases.

Occlusion of retinal capillaries caused by glial cell proliferation in chronic ocular inflammation.

The inner blood-retinal barrier is a gliovascular unit in which glial cells surround capillary endothelial cells and regulate retinal capillaries by paracrine interactions. During chronic ocular inflammation, microvascular complications can give rise to vascular proliferative lesions, which compromise visual acuity. This pathologic remodelling caused by proliferating Müller cells determines occlusion of retinal capillaries. The aim of the present study was to identify qualitative and quantitative alterations in the retinal capillaries in patients with post-traumatic chronic ocular inflammation or post-thrombotic vascular glaucoma. Moreover, we investigated the potential role of vascular endothelial growth factor (VEGF) and pro-inflammatory cytokines in retinal inflammation. Our electron microscopy findings demonstrated that during chronic ocular inflammation, thickening of the basement membrane, loss of pericytes and endothelial cells and proliferation of Müller cells occur with irreversible occlusion of retinal capillaries. Angiogenesis takes place as part of a regenerative reaction that results in fibrosis. We believe that VEGF and pro-inflammatory cytokines may be potential therapeutic targets in the treatment of this disease although further studies are required to confirm these findings.

Alterações eletrofisiológicas na doença de Oguchi

Descrever as alteracoes eletrofuncionais em um caso rarissimo da Doenca de Oguchi. Paciente do sexo feminino, italiana de 17 anos de idade se queixava de cegueira noturna. A resposta escotopica de bastonetes, do ERG era nao registravel. A resposta escotopica ao estimulo branco forte demonstrava uma diminuicao de amplitude da onda B. As respostas ao flicker de 30Hz e ao EOG eram dentro dos limites da normalidade. Era presente o fenomeno de Mizuo-Nakamura. Os exames eletrofuncionais sao muito importantes no diagnostico de certeza da doenca de Oguchi. E nitida, no presente caso, a discordância entre EOG e ERG. Considerando a funcao dos bastonetes, as respostas normais do EOG contrastam com a ausencia de respostas dos bastonetes em condicoes escotopicas no ERG. Mais estudos sao necessarios para entender o complexo mecanismo eletrofuncional dessa doenca e melhor definir a origem dos componentes sensiveis a luz do EOG.