The Conjunctiva-Associated Lymphoid Tissue in Chronic Ocular Surface Diseases.

Ocular surface diseases (OSDs) represent a widely investigated field of research given their growing incidence and the negative impact on quality of life. During OSDs, cytokines generated by damaged epithelia trigger and deregulate the lymphoid cells composing the eye-associated lymphoid tissues, inducing an immune-mediated chronic inflammation that amplifies and propagates the disease during time. The conjunctiva-associated lymphoid tissue (CALT), given its particular position that permits immune cells covering the cornea, might play a crucial role in the development of OSDs. Despite the recognized inflammatory role of mucosa-associated lymphoid tissues in other stations taking contact with the external environment (gut or bronchus), CALT did not gain the deserved consideration. In the last years, the diffusion of the in vivo confocal microscopy (IVCM) stimulated the interest to CALT, especially in dry eye, ocular allergy, and glaucoma. Though the initial stimuli were different, IVCM documented similar changes, represented by increased lymphoid cells within the diffuse layer, follicles and interfollicular spaces. These findings, which need to be validated by immunohistology, support the CALT stimulation during OSDs. However, while an involvement of the CALT in OSDs is hypothesizable, the exact role of this structure in their pathogenesis remains unclear and warrants further investigations.

Intravitreal ranibizumab for predominantly hemorrhagic choroidal neovascularization in age-related macular degeneration.

PURPOSE: To evaluate the effects of intravitreal ranibizumab monotherapy on predominantly hemorrhagic choroidal neovascularization with foveal involvement associated with age-related macular degeneration. MATERIALS AND METHODS: Twenty-two consecutive eyes with hemorrhagic neovascularization were treated with 3 monthly intravitreal ranibizumab injections. Additional injections were administered according to retreatment criteria during 12 months of follow-up. RESULTS: A mean of 6.64 ± 1.36 injections was administered. Overall, the mean visual acuity increased from 10.90 ± 6.02 to 12.81 ± 8.34 ETDRS letters (p > 0.05) at 12 months. The 'early treatment group' gained a mean of 2.83 ± 2.24 ETDRS letters (p < 0.05), while the 'late treatment group' gained a mean of 0.30 ± 1.25 ETDRS letters (p > 0.05) with significant differences between the groups (p < 0.05). A progressive resolution of macular bleeding was registered in 20 patients (mean time: 5.3 ± 1.6 months). CONCLUSIONS: Ranibizumab injections can be considered a beneficial approach for the management of predominantly hemorrhagic choroidal neovascularization with foveal involvement associated with age-related macular degeneration. Furthermore, the time interval between hemorrhage and the first injection seems to be an important predicting factor of final visual acuity.

Trans-conjunctival aqueous humor outflow in glaucomatous patients treated with prostaglandin analogues: an in vivo confocal microscopy study.

PURPOSE: To analyze, using in vivo laser scanning confocal microscopy (LSCM), the conjunctival features in glaucomatous patients receiving prostaglandin analogues (PGA). METHODS: Eighty eyes of 80 consecutive glaucomatous patients naive for therapy were enrolled; 30 eyes of 30 healthy subjects served as a control. Patients were randomized to: preservative-free (PF) and preserved latanoprost (groups 1 and 2, respectively), PF and preserved timolol (groups 3 and 4), and controls to vehicle of latanoprost or physiological buffered saline solution (groups 5 and 6). All subjects underwent LSCM of bulbar conjunctiva at baseline and 3 months after initiating therapy. The main outcomes were: mean density (MMD: cysts/mm(2)) and mean area (MMA: cysts/mm(2)) of epithelial microcysts. The relations between MMA and MMD with intraocular pressure (IOP), age, and mean defect (MD), were analyzed. RESULTS: At baseline, microcysts were found in all subjects. At month three, MMD did not change in all groups (p > 0.05). MMA significantly increased only in group 1 from 2,158.81 ± 524.09 to 3,877.77 ± 867.31, and in group 2 from 2,019.71 ± 541.03 to 5,560.39 ± 1,176.14, with values significantly higher in group 2 (p < 0.001). Significant relations were not found between MMD and MMA with IOP, MD, and age (p > 0.05). CONCLUSIONS: PGA increased MMA in therapy-naive glaucomatous patients, indicating a possible enhancement of the trans-conjunctival aqueous humor outflow. Therefore, conjunctiva seems an additional target tissue to evaluate the hydrodynamic pathways in glaucoma and modifications induced by medical therapy.

In vivo laser scanning confocal microscopy of the ocular surface in glaucoma.

Over the past decade, knowledge about the ocular surface in glaucoma has significantly increased through the use of in vivo laser scanning confocal microscopy (LSCM). This in vivo imaging method can show modifications at the cellular level induced by anti-glaucoma drugs on ocular surface structures and adnexa in the eye. High-quality images of the conjunctiva, cornea, limbus, meibomian glands, and lymphoid structures during therapy can be obtained. In addition, LSCM opened new fields of research on the patho-physiology of aqueous humor (AH) hydrodynamics in untreated, and in medically or surgically treated glaucomatous patients. In these conditions, an enhancement of the trans-scleral AH outflow contributed to clarification of the mechanism of action of different anti-glaucoma medications and surgical approaches. Finally, the use of LSCM represented a huge advance in evaluation of bleb functionality after filtration surgery, defining the hallmarks of AH filtration through the bleb-wall and distinguishing functional from nonfunctional blebs. Thus, signs seen with LSCM may anticipate clinical failure, guiding the clinician in planning the appropriate timing of the various steps in bleb management. In this review we summarize the current knowledge about in vivo LSCM of the ocular surface in glaucoma.

Reproducibility and repeatability of Cirrus™ HD-OCT peripapillary retinal nerve fibre layer thickness measurements in young normal subjects.

PURPOSE: To assess the reproducibility and repeatability of peripapillary retinal nerve fibre layer (RNFL) thickness measurements using a spectral-domain optical coherence tomography (SD-OCT) device in healthy subjects. METHODS: In this observational study, 68 young Caucasian healthy volunteers (68 eyes) were subjected to Cirrus™ high-definition (HD) OCT (Zeiss) peripapillary RNFL thickness measurements by two experienced examiners in two different sessions. Average, 4-quadrant and 12-clock-hour sector RNFL thicknesses were analysed. For each option, intra-observer, intrasession repeatability and interobserver, intersession reproducibility were tested. To assess the repeatability of measurements, the Bland and Altman plots were used and the coefficient of repeatability was calculated. Interobserver and intersession reproducibilities were analysed by means of concordance correlation coefficients (CCCs). RESULTS: The sample age ranged from 21 to 39 years (mean 29.09, standard deviation ±5.21). The average RNFL thickness ranged from 90.97 to 91.46 and from 91.34 to 91.78 µm, for the first and the second operator, respectively. The highest repeatability and reproducibility were obtained for average RNFL thickness with coefficients of repeatability of 5.30 and 6.05 µm for the first and the second operator, interoperator CCCs of 0.95 and 0.96 for the first and the second session, and intersession CCCs of 0.96 and 0.97 for the first and the second operator, respectively. CONCLUSIONS: Cirrus OCT peripapillary average RNFL thickness measurement in young healthy subjects showed high interoperator and intersession reproducibility. Intrasession repeatability as tested by coefficient of repeatability was next to the device resolution, with very similar results between the two operators. When analysing quadrant and clock hour sector RNFL thickness measurements, both repeatability and reproducibility tend to decrease.

Filtering bleb functionality: a clinical, anterior segment optical coherence tomography and in vivo confocal microscopy study.

PURPOSE: To provide a microscopic and macroscopic analysis by a clinical, in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) assessment of filtering blebs after glaucoma surgery. MATERIAL AND METHODS: We retrospectively analyzed 60 eyes of 48 glaucomatous patients by slit-lamp, IVCM, and AS-OCT examinations. Patients were divided into 2 groups: successful blebs (group 1, 16 patients, 27 eyes) were defined as a one-third reduction in preoperative intraocular pressure without antiglaucoma medications and failed blebs (group 2, 32 patients, 33 eyes) as a less than one-third reduction in preoperative intraocular pressure without therapy. The examinations were performed from 1 to 96 months postoperatively. RESULTS: Diffuse or cystic clinical patterns were indicative for good functionality whereas flat or encapsulation was indicative for poor functionality. When comparing successful with failed blebs, the IVCM analysis showed a greater number (P=0.014), density (P=0.009), and total area of epithelial microcysts (P=0.017) and a lower density of connective tissue (P=0.006). The AS-OCT analysis showed a lower degree of bleb wall reflectivity (P<0.001). A significant correlation was found between the clinical and AS-OCT parameters, particularly for the cystic (100%) and diffuse (74%) patterns. CONCLUSIONS: All IVCM parameters did correlate well with the bleb functionality whereas, among the AS-OCT parameters, only the bleb wall reflectivity was significantly related to the filtering capability. Clinical and AS-OCT bleb classification showed a significant degree of concordance. As a consequence, simultaneous approach by clinical, microscopic, and tomographic assessment improves the clinician's ability in the postsurgery understanding and management of blebs.

Optical Coherence Tomography Angiography of the Peripapillary Retina in Normal-Tension Glaucoma and Chronic Nonarteritic Anterior Ischemic Optic Neuropathy.

PURPOSE: To analyze the retinal radial peripapillary capillary (RPC) network in normal-tension glaucoma (NTG) and nonarteritic anterior ischemic optic neuropathy (NAION) eyes using optical coherence tomography angiography (OCTA). MATERIAL AND METHODS: Twenty-two patients with NTG, 22 patients with unilateral chronic NAION, and 23 age-matched controls were enrolled. Patients underwent OCTA to obtain en face angiograms of the peripapillary region. The main outcome measures were as follows: (1) the whole en face image perfusion density (WPD) and (2) the circumpapillary perfusion density (CPD). RESULTS: Mean ± SD age was 66.3 ± 7.0 years in the NTG group, 68.1 ± 4.3 years in the NAION group, and 63.9 ± 7.0 years in the control group (p > 0.05 for all the comparisons). The visual field mean defect (MD) was worse in patients than in controls (p < 0.0001), but did not differ between NTG and NAION (-9.6 ± 2.6 dB and -8.2 ± 2.6 dB, respectively). The WPD was 0.41 ± 0.04 in the NTG group (p < 0.0001 in comparison with healthy subjects and NAION patients), 0.46 ± 0.04 in the NAION group (p < 0.0001 in comparison with the control group), and 0.56 ± 0.03 in the control group. The CPD was significantly reduced in both NTG (0.48 ± 0.04, p < 0.0001) and NAION eyes (0.52 ± 0.05, p < 0.0001), after comparison to control eyes (0.59 ± 0.03). Moreover, the CPD was significantly lower in NTG than in NAION eyes (p = 0.006). CONCLUSIONS: OCTA documented a reduction of the peripapillary perfusion in NTG and unilateral NAION. In presence of similar functional damage, the lower perfusion densities in NTG may indicate greater vascular alterations in chronic compared to acute ischemic optic neuropathies.

Meibomian Gland Features and Conjunctival Goblet Cell Density in Glaucomatous Patients Controlled With Prostaglandin/Timolol Fixed Combinations: A Case Control, Cross-sectional Study.

PURPOSE: To investigate, using in vivo confocal microscopy (IVCM), the Meibomian gland (MG) features and conjunctival goblet cell density (GCD) in glaucomatous patients controlled with prostaglandin/timolol fixed combinations (PTFCs). MATERIALS AND METHODS: In this cross-sectional study, 60 white patients were treated with PTFCs, 15 with latanoprost+timolol (L+T) unfixed combination, and 15 controls were enrolled. Patients underwent the Ocular Surface Disease Index questionnaire, tear film breakup time, corneal staining, Schirmer test I, and IVCM of MGs and goblet cells. The main outcome measures were: mean Meibomian acinar density (MMAD) and area (MMAA), inhomogeneity of glandular interstice (InI) and acinar wall (InAW), and GCD. RESULTS: PTFCs were: latanoprost/timolol (LTFC, 15 eyes), travoprost/timolol (TTFC, 15), bimatoprost/timolol (BTFC, 15), and preservative-free bimatoprost/timolol (PF-BTFC, 15) fixed combinations. Mean time on therapy did not differ among treatments. IVCM documented lower GCD, MMAD, and MMAA (P<0.001), and greater InI and InAW (P<0.05) in glaucoma patients compared with controls. L+T showed worse values compared with PTFCs and PF-BTFC (P<0.05). Preserved PTFCs showed lower MMAD, MMAA, GCD, and greater InI and InAW compared with PF-BTFC (P<0.05) and controls (P<0.001). Differences were not found among PTFCs. InI and InAW significantly correlated with Ocular Surface Disease Index and breakup time (P<0.001), corneal staining (P<0.05), and GCD (P<0.001); GCD correlated with MMAD (P<0.05). CONCLUSIONS: PTFCs were less toxic towards MGs and goblet cells compared with the L+T unfixed combination, with PF-BTFC presenting the most tolerated profile. These findings should be carefully considered given the role of these structures in the induction of the glaucoma-related ocular surface disease.

High-Intensity Focused Ultrasound Circular Cyclocoagulation in Glaucoma: A Step Forward for Cyclodestruction?

The ciliary body ablation is still considered as a last resort treatment to reduce the intraocular pressure (IOP) in uncontrolled glaucoma. Several ablation techniques have been proposed over the years, all presenting a high rate of complications, nonselectivity for the target organ, and unpredictable dose-effect relationship. These drawbacks limited the application of cyclodestructive procedures almost exclusively to refractory glaucoma. High-intensity focused ultrasound (HIFU), proposed in the early 1980s and later abandoned because of the complexity and side effects of the procedure, was recently reconsidered in a new approach to destroy the ciliary body. Ultrasound circular cyclocoagulation (UC3), by using miniaturized transducers embedded in a dedicated circular-shaped device, permits to selectively treat the ciliary body in a one-step, computer-assisted, and non-operator-dependent procedure. UC3 shows a high level of safety along with a predictable and sustained IOP reduction in patients with refractory glaucoma. Because of this, the indication of UC3 was recently extended also to naïve-to-surgery patients, thus reconsidering the role and timing of ciliary body ablation in the surgical management of glaucoma. This article provides a review of the most used cycloablative techniques with particular attention to UC3, summarizing the current knowledge about this procedure and future possible developments.

Three-dimensional Laser Scanning Confocal Analysis of Conjunctival Microcysts in Glaucomatous Patients Before and After Trabeculectomy.

BACKGROUND/AIM: In glaucoma, conjunctival epithelial microcysts (CEM) have been extensively investigated by means of laser scanning confocal microscopy. In the present case series, we examined eight glaucomatous patients undergoing trabeculectomy to obtain a 3-dimensional (3-D) characterization of CEM. MATERIALS AND METHODS: Image acquisition was performed in z-scan automatic volume mode by Heidelberg Retina Tomograph III/Rostock Cornea Module and a series of 40 images of 300×300 µm (384×384 pixels) to a maximum depth of 40 µm were acquired throughout the upper bulbar conjunctiva before (at the site planned for surgery) and eight weeks after trabeculectomy. The 3-D volume tissue reconstruction with maximal size of 300×300×40 µm was obtained. RESULTS: In the enface view, CEM appeared as empty, optically clear, round or oval shaped sub-epithelial structures. The 3-D spatial reconstruction showed microcysts as oval-shaped and optically clear elements, which were close, but clearly separated from the epithelium. CEM were embedded in the extra-cellular spaces and located about 10 µm below the epithelial surface. After trabeculectomy, CEM increased density and area especially along the horizontal axis. CONCLUSION: The 3-D in vivo confocal reconstruction of CEM permits for better clarification of their microscopic anatomy and patho-physiological significance, confirming their involvement in AH flow through the bleb-wall after filtration surgery for glaucoma.

In Vivo Confocal Imaging of the Conjunctiva as a Predictive Tool for the Glaucoma Filtration Surgery Outcome.

Purpose: To examine the preoperative conjunctival dendritic cell density (DCD), goblet cell density (GCD), and stromal meshwork reflectivity (SMR) in glaucomatous patients undergoing filtration surgery, using in vivo confocal microscopy (IVCM). Methods: Sixty-six patients were enrolled. At baseline, IVCM was performed at the site planned for surgery, and was repeated after 12 months at bleb site. Surgery was successful when a one-third reduction of baseline IOP was obtained at the last follow-up. The main outcomes were baseline DCD, GCD, and SMR, and 12 months IOP. The relations between baseline confocal parameters and 12 months IOP were analyzed. Results: Filtration surgery was successful in 43 patients (group 1: complete success, 25; group 2: qualified success, 18), and unsuccessful in 23 patients (group 3). Baseline IOP (mm Hg) was 27.6 ± 2.8, 28.8 ± 4.1, and 27.7 ± 3.2 in groups 1 to 3, respectively. Preoperative DCD and SMR were lower in group 1 compared with groups 2 (P < 0.001, P < 0.05), and 3 (P < 0.001); preoperative GCD was higher in group 1 compared with groups 2 and 3 (P < 0.001). DCD and GCD were also different between groups 2 and 3 (P < 0.05, P < 0.001). At 12 months, IOP reduced by 43.3%, 38.4%, and 15.8% in groups 1 to 3. Twelve-month IOP reduction negatively correlated with baseline DCD and SMR (P < 0.001, r = -0.786; P < 0.05, r = -0.618), and positively with GCD (P < 0.001, r = 0.752). Conclusions: Preoperative DCD, GCD, and SMR are parameters correlated with the filtration surgery outcome, with DCD presenting the strongest correlation. IVCM of the conjunctiva may represent an imaging tool to predict the surgical success in glaucoma.

In Vivo Laser Scanning Confocal Microscopy of Human Meibomian Glands in Aging and Ocular Surface Diseases.

Meibomian glands (MGs) play a crucial role in the ocular surface homeostasis by providing lipids to the superficial tear film. Their dysfunction destabilizes the tear film leading to a progressive loss of the ocular surface equilibrium and increasing the risk for dry eye. In fact, nowadays, the meibomian gland dysfunction is one of the leading causes of dry eye. Over the past decades, MGs have been mainly studied by using meibography, which, however, cannot image the glandular structure at a cellular level. The diffusion of the in vivo laser scanning confocal microscopy (LSCM) provided a new approach for the structural assessment of MGs permitting a major step in the noninvasive evaluation of these structures. LSCM is capable of showing MGs modifications during aging and in the most diffuse ocular surface diseases such as dry eye, allergy, and autoimmune conditions and in the drug-induced ocular surface disease. On the other hand, LSCM may help clinicians in monitoring the tissue response to therapy. In this review, we summarized the current knowledge about the role of in vivo LSCM in the assessment of MGs during aging and in the most diffuse ocular surface diseases.

Uveo-scleral outflow pathways after ultrasonic cyclocoagulation in refractory glaucoma: an anterior segment optical coherence tomography and in vivo confocal study.

AIMS: To evaluate, using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM), the uveo-scleral aqueous humour (AH) outflow pathways after ultrasonic circular cyclocoagulation (UCCC). METHODS: Forty-four patients with refractory glaucoma underwent 4 or 6 s UCCC (group 1, 24 eyes; group 2, 20 eyes). UCCC was successful when the preoperative intraocular pressure (IOP) reduced by one-third. AS-OCT and IVCM were performed at baseline and at month 1 to evaluate the sclera and conjunctiva. The main outcomes were mean intra-scleral hyporeflective spaces area (MIHSA: mm2) at AS-OCT, mean density and area of conjunctival microcysts (MMD: cysts/mm2; MMA: µm2) at IVCM. The relations between MIHSA, MMA and MMD with IOP were analysed. RESULTS: Mean baseline IOP was 26.9±2.8 mm Hg in group 1 and 27.5±4.0 in group 2. Intra-scleral hyporeflective spaces and microcysts were observed in both groups, without significant differences in MIHSA, MMA and MMD. At month 1, UCCC was successful in 63.6% of patients (41.6% in group 1, 80% in group 2), and IOP reduced to 18.8±3.2 (30.1%) and 17.1±2.7 mm Hg (38.7%), respectively (p<0.001). MIHSA showed a twofold and threefold increase in group 1 and 2 (p<0.05), with a significant difference between groups (p<0.05). MMA and MMD increased in both groups (p<0.05), with values higher in group 2 (p<0.05). Significant relations were found between MIHSA and IOP in both groups (p<0.01). CONCLUSIONS: UCCC induced anatomical modifications of sclera and conjunctiva, which suggested that the trans-scleral AH outflow enhancement is one of the possible mechanisms exploited by ultrasounds to reduce IOP.

In Vivo Goblet Cell Density as a Potential Indicator of Glaucoma Filtration Surgery Outcome.

PURPOSE: We analyzed the preoperative conjunctival goblet cell density (GCD), MUC5AC, and HLA-DR in glaucomatous patients undergoing trabeculectomy, using laser scanning confocal microscopy (LSCM) and impression cytology (IC). METHODS: We enrolled 57 patients undergoing trabeculectomy. At baseline LSCM and IC were performed at the site planned for surgery; LSCM was repeated after 12 months at the bleb site. The main outcomes were: GCD, mean microcyst density (MMD) and area (MMA) at LSCM, MUC5AC, and HLA-DR positivity at IC, and IOP. The relationships between baseline GCD, and 12-month IOP, MMD, and MMA were analyzed. RESULTS: Trabeculectomy was successful in 39 patients (complete success in 27, Group 1; qualified in 12, Group 2), and unsuccessful in 18 (Group 3). At baseline IOP (mm Hg) was 27.2 ± 3.12, 27.5 ± 2.23, and 27.7 ± 1.90 in Groups 1 to 3, respectively; GCD and MUC5AC positivity were higher in Group 1 compared to Groups 2 and 3 (P < 0.05); HLA-DR, MMD, and MMA were not significantly different among the groups. At 12 months, IOP reduced by 45.3%, 35.4%, and 12.8% in Groups 1 to 3, respectively. Goblet cell density did not change in Group 1, whereas it was reduced in Groups 2 and 3 (P < 0.05), with values lower in Group 3. Mean microcyst density and MMA increased in Groups 1 and 2 (P < 0.05), with values higher in Group 1 (P < 0.05). Baseline GCD positively correlated with 12-month IOP reduction (P < 0.001, r = 0.641), MMD (P < 0.05, r = 0.454), and MMA (P < 0.001, r = 0.541). CONCLUSIONS: Goblet cells positively affect the filtration ability after trabeculectomy; therefore, preoperative GCD could be considered as a potential in vivo biomarker of surgical success.

In Vivo Distribution of Corneal Epithelial Dendritic Cells in Patients With Glaucoma.

PURPOSE: The purpose of this study was to evaluate dendritic cell (DC) distribution, morphology, and DC density in the entire cornea of medically controlled glaucoma patients (MCGP), using in vivo confocal microscopy (IVCM). METHODS: Fifty MCGP were enrolled, 15 patients with dry eye, and 15 healthy subjects served as controls. Patients were asked to complete the Ocular Surface Disease Index (OSDI) questionnaire and then underwent tear film break-up time (BUT), corneal staining, and Schirmer test (ST) I and then IVCM. In vivo confocal microscopy evaluated the limbal and central DC density, the DCs morphology and distribution. Relationships among DC density, OSDI score, and corneal staining were analyzed. RESULTS: Medically controlled glaucoma patients were divided into 2 groups; group 1 (29 eyes) was tested with one drug; group 2 (21 eyes) was tested with ≥2 drugs. Dendritic cells were significantly higher at limbus than at central cornea in both groups. Limbal DCs were found in the 86.7%, 89.7%, 90.4%, and 93.3% of eyes in controls, groups 1 and 2, and DED; central corneal DCs were found in the 26.6%, 75.9%, 80.9%, and 86.6% of eyes in controls, groups 1 and 2, and DED. Dendritic cell density was higher in glaucoma groups and DED than in controls (P < 0.001). Group 2 and DED presented DC density significantly higher compared with group 1 (P < 0.05). In group 1 DC density was higher in patients taking preserved drugs than in those taking preservative-free drugs (P < 0.05). Dendritic cell density was higher in DED than in group 2 (P < 0.05). Dendritic cell density significantly correlated with corneal staining and OSDI (P < 0.001). CONCLUSIONS: Dendritic cells increase in the entire cornea of MCGP, with a higher density at limbus. These modifications may take part in the induction of the glaucoma-related ocular surface disease.

Fractal dimension as a new tool to analyze optic nerve head vasculature in primary open angle glaucoma.

AIM: To investigate the features of optic nerve head (ONH) microvasculature in primary open angle glaucoma using fractal geometry analysis. PATIENTS AND METHOD: ONH blood flow was analyzed at the level of the lamina cribrosa by means of confocal scanning laser Heidelberg Doppler flowmetry (HRF) in medically-controlled early and advanced glaucoma. Fractal dimension D of vasculature map was calculated using the Box Counting. RESULTS: Our data demonstrated that, in patients with advanced glaucoma, fractal dimension D was significantly lower than in controls, whereas, in the early stage of disease, its value was similar. Fractal dimension D of microcirculation was significantly and negatively correlated with the cup-disk area ratio in both early and advanced glaucoma groups, whereas linear cup-disk ratio of the disk, cup shape measure and nerve fiber layer thickness, where correlated only in advanced stage of the disease. CONCLUSION: These findings demonstrate that fractal dimension D of ONH appeared significantly reduced in advanced glaucoma and correlated with the optic disc damage.

Molecular biomarkers in primary open-angle glaucoma: from noninvasive to invasive.

Glaucoma, the first cause of irreversible blindness worldwide, is a neurodegenerative disease characterized by the progressive loss of retinal ganglion cells. There are different subtypes of glaucoma, all expression of a common optic neuropathy; primary open-angle glaucoma (POAG) is the most diffuse subtype in western countries. To date, unfortunately, several questions still remain unsolved in the glaucoma management, such as the availability of powerful methods for screening high-risk populations, early diagnosis, timely detection of damage progression, and prediction of response to therapy. Over the last years, biomarkers have gained immense scientific and clinical interest to solve these issues, with countless molecules that have been candidate as potential biomarkers. In the present review, we summarize the current knowledge about the most robust molecular biomarkers proposed in POAG, distinguishing noninvasive from minimally invasive, and invasive biomarkers, according to the procedure adopted to collect fluid samples.

Advance in the pathogenesis and treatment of normal-tension glaucoma.

Normal-tension glaucoma (NTG) is a multifactorial disease where mechanical stresses and vascular alterations to the optic nerve head probably represent the key pathogenic moments. Although intraocular pressure (IOP) plays a crucial role in the retinal ganglion cell loss, the IOP reduction does not necessarily reduces the disease progression. Therefore, several IOP-independent factors such as glutamate toxicity, oxidative stress, autoimmunity, and vascular dysregulation have been considered in the pathogenesis of NTG. Numerous evidences documented an impairment of the ocular blood flow, involved both in the onset and progression of the disease. The IOP reduction remains the main strategy to reduce the damage progression in NTG. Recently, new treatment strategies have been proposed to improve the control of the disease. Neuroprotection is a rapidly expanding area of research, which represents a promising tool. In the present review, we summarize the recent scientific advancements in the pathogenesis and treatment of NTG.

Advanced Morphological and Functional Magnetic Resonance Techniques in Glaucoma.

Glaucoma is a multifactorial disease that is the leading cause of irreversible blindness. Recent data documented that glaucoma is not limited to the retinal ganglion cells but that it also extends to the posterior visual pathway. The diagnosis is based on the presence of signs of glaucomatous optic neuropathy and consistent functional visual field alterations. Unfortunately these functional alterations often become evident when a significant amount of the nerve fibers that compose the optic nerve has been irreversibly lost. Advanced morphological and functional magnetic resonance (MR) techniques (morphometry, diffusion tensor imaging, arterial spin labeling, and functional connectivity) may provide a means for observing modifications induced by this fiber loss, within the optic nerve and the visual cortex, in an earlier stage. The aim of this systematic review was to determine if the use of these advanced MR techniques could offer the possibility of diagnosing glaucoma at an earlier stage than that currently possible.

Corneoscleral limbus in glaucoma patients: in vivo confocal microscopy and immunocytological study.

PURPOSE: To investigate morphologic changes of the corneoscleral limbus in glaucoma patients using laser scanning confocal microscopy (LSCM) and impression cytology (IC). METHODS: Eighty patients with glaucoma and 20 with dry eye were enrolled; 20 healthy subjects served as controls. Patients underwent the Ocular Surface Disease Index (OSDI) questionnaire, tear film break-up time, corneal staining, Schirmer test I, and LSCM of the limbus. Laser scanning confocal microscopy evaluated the limbal transition epithelium (LTE) regularity, dendritic cell (DC) density, and palisades of Vogt (POV). Impression cytology was performed and samples stained with HLA-DR and IL6. RESULTS: Glaucomatous patients were divided into three groups: Group 1 (40 eyes): one drug; Group 2 (20): two drugs; and Group 3 (20): three or more drugs. Limbal transition epithelium regularity was worse, and DC density higher in Groups 2, 3, and dry eyes compared with Group 1 and controls (P < 0.01). Preserved drugs worsened LTE regularity and induced higher DC density compared with preservative-free (PF) drugs (P = 0.041; P = 0.004). Despite typical POV architecture was preserved, signs of inflammation were found in glaucoma groups. HLA-DR and IL-6 positivity were higher in Groups 2, 3, and dry eye compared with controls (P < 0.001), and in preserved versus PF drugs (P < 0.05; P < 0.001). Dendritic cell density and LTE regularity correlated with HLA-DR, IL-6, and OSDI score in glaucoma groups and dry eyes (P < 0.001). CONCLUSIONS: Laser scanning confocal microscopy and IC documented antiglaucoma therapy induced morphologic alterations of limbus, which may play a role in the glaucoma-related ocular surface disease. Further studies are required to determine if limbal changes affect stem cell viability.