Exploring Epigenetic Modifications as Potential Biomarkers and Therapeutic Targets in Glaucoma

Glaucoma, a complex and multifactorial neurodegenerative disorder, is a leading cause of irreversible blindness worldwide. Despite significant advancements in our understanding of its pathogenesis and management, early diagnosis and effective treatment of glaucoma remain major clinical challenges. Epigenetic modifications, encompassing deoxyribonucleic acid (DNA) methylation, histone modifications, and non-coding RNAs, have emerged as critical regulators of gene expression and cellular processes. The aim of this comprehensive review focuses on the emerging field of epigenetics and its role in understanding the complex genetic and molecular mechanisms underlying glaucoma. The review will provide an overview of the pathophysiology of glaucoma, emphasizing the intricacies of intraocular pressure regulation, retinal ganglion cell dysfunction, and optic nerve damage. It explores how epigenetic modifications, such as DNA methylation and histone modifications, can influence gene expression, and how these mechanisms are implicated in glaucomatous neurodegeneration and contribute to glaucoma pathogenesis. The manuscript discusses evidence from both animal models and human studies, providing insights into the epigenetic alterations associated with glaucoma onset and progression. Additionally, it discusses the potential of using epigenetic modifications as diagnostic biomarkers and therapeutic targets for more personalized and targeted glaucoma treatment.

Focus on limbal stem cell deficiency and limbal cell transplantation

Limbal stem cell deficiency (LSCD) causes severe vision impairment and can lead to blindness, representing one of the most challenging ocular surface disorders. Stem cell deficiency can be congenital or, more often, acquired. The categorization of ocular surface transplantation techniques is crucial to achieving treatment homogeneity and quality of care, according to the anatomic source of the tissue being transplanted, genetic source, autologous or allogenic transplantation (to reflect histocompatibility in the latter group), and cell culture and tissue engineering techniques. The aim of this minireview is to provide a summary of the management of LSCD, from clinical characteristics and therapeutic outcomes to the development of novel therapeutic approaches. The manuscript also briefly summarizes recent findings in the current literature and outlines the future challenges to overcome in the management of the major types of ocular surface failure.

Improving keratoconus management with central cor neal regularization and corneal collagen cross-linking protocol treatment

PURPOSE

To evaluate safety and efficacy of customized central corneal regularization (CCR), together with simultaneous accelerated corneal collagen cross-linking (A-CXL) - CCR-CXL protocol, to treat keratoconus-related corneal ectasia.

DESIGN

Retrospective, comparative observational case series.

METHODS

Patients that had undergone combined CCR-CXL protocol. Main inclusion criteria were keratoconus visual acuity deterioration and contact lens intolerance. All patients underwent complete ophthalmological evaluation, corrected distance visual acuity (CDVA) and Scheimpflug-corneal tomography. Central corneal regularization was performed by ablation using flying spot laser. Subsequently, the stroma was saturated with 0.17% riboflavin-5-phosphate added every 2 minutes, followed by A-CXL 9 mW/cm2 for 10 minutes. CDVA, medium keratometry value (Kmed), and total corneal morphological irregularity index (CMI) of patients were analyzed before surgery and after 1, 3 and 12 months. A P value of .05 or less was considered statistically significant.

RESULTS

46 eyes of 39 keratoconus patients were treated. At 1 month, the mean CDVA (LogMar) increased from 0.19 ± 0.02 to 0.12 ± 0.02 (P < .05), and the difference remained stable at month 12. Kmax decrease was statistically significant from 57.02 ± 5.65 to 50.21 ± 4.48 (P < .05). CMI decreased significantly from 47.8 ± 2.84 to 30.1 ± 2.4 (P < .01).

CONCLUSIONS

CCR-CXL protocol is safe and effective in arresting keratectasia progression and increasing corneal optic regularity in keratoconus. These findings showed a significant improvement in CDVA, keratometry values and corneal optical aberrations after being treated with the CCR-CXL protocol.

Visuo-Acoustic Stimulation's Role in Synaptic Plasticity: A Review of the Literature

Brain plasticity is the capacity of cerebral neurons to change, structurally and functionally, in response to experiences. This is an essential property underlying the maturation of sensory functions, learning and memory processes, and brain repair in response to the occurrence of diseases and trauma. In this field, the visual system emerges as a paradigmatic research model, both for basic research studies and for translational investigations. The auditory system remains capable of reorganizing itself in response to different auditory stimulations or sensory organ modification. Acoustic biofeedback training can be an effective way to train patients with the central scotoma, who have poor fixation stability and poor visual acuity, in order to bring fixation on an eccentrical and healthy area of the retina: a pseudofovea. This review article is focused on the cellular and molecular mechanisms underlying retinal sensitivity changes and visual and auditory system plasticity.

Corneal stromal demarcation line after 4 protocols of corneal crosslinking in keratoconus determined with anterior segment optical coherence tomography

PURPOSE

To use anterior segment optical coherence tomography (AS-OCT) to compare corneal stromal demarcation line depth after 4 treatment protocols of corneal crosslinking (CXL).

SETTING

Eye Clinic, Sapienza University of Rome, Terracina (Latina), Italy.

DESIGN

Prospective case series.

METHODS

Patients with progressive keratoconus were delegated to one of the following CXL treatments: (1) conventional epithelium (epi)-off 3 mW/cm² according to the standard Dresden protocol (C-CXL group), (2) accelerated epi-off 10 mW/cm² (A-CXL group), (3) transepithelial epi-on 3 mW/cm² (TE-CXL group), or (4) transepithelial epi-on by iontophoresis 10 mW/cm² (I-CXL group). Two independent observers measured the corneal stromal demarcation line using AS-OCT.

RESULTS

The study comprised 70 patients (120 eyes, 30 eyes in each group). The corneal stromal demarcation line was identified on AS-OCT scans in 109 eyes (90.8%). One month after the treatment, the mean stromal demarcation line depth was 275.05 μm ± 41.83 (SD) in the C-CXL group, 279.35 ± 33.07 μm in the A-CXL group, 132.60 ± 22.14 μm in the TE-CXL group, and 235.40 ± 37.08 μm in the I-CXL group. The difference in stromal demarcation line depth was not statistically significant between the C-CXL and A-CXL group, but it was statistically significant (P < .05) between the epi-off and epi-on CXL groups and between the 2 epi-on groups, where the demarcation line was significantly deeper in the I-CXL group than in the TE-CXL group.

CONCLUSION

The corneal stromal demarcation line was significantly deeper after epi-off 30-minute standard CXL treatment and after epi-off 9-minute accelerated CXL with high-intensity ultraviolet-A irradiation.

A new method to assess foveal morphology with optical coherence tomography

PURPOSE

To measure foveal morphology using optical coherence tomography (OCT).

METHODS

Three examiners classified normal subjects and patients with macular edema and epiretinal membranes from a normative database (299 OCT scans) and a study sample (80 OCT scans) on the basis of the foveal depression appearance (reference classification). The following parameters were measured for each OCT scan: Central Foveal Thickness (CFT), Central Subfield Thickness (CST), Central Subfield Volume (CSV), Centrofoveal Index (CI), Parafoveal Index (PI), and Foveal Indices (FI1, FI2, FI3). Foveal depression of OCT scans in the study sample were classified based on the values of OCT parameters using Bayesian statistics (test classifications).

RESULTS

Agreement between reference and test classifications was of 70% for CFT, 58.7% for CST, 60% for CSV, 80% for CI, 72.5% for PI, 88.7% for FI1, 96.2% for FI2 and 97.5% for FI3.

CONCLUSIONS

IF3 seems to provide a reliable measure of the foveal morphology.

Different graft thicknesses after Descemet stripping endothelial keratoplasty for bullous keratopathy in the two eyes of the same patient

Objective

To describe a very unique case of two Descemet stripping automated endothelial keratoplasty (DSAEK) surgeries performed in both eyes of the same patient with an extremely different graft thickness and overall corneal thickness but with the same corrected distance visual acuity (CDVA) 2 years after surgery.

Case presentation

A 75-year-old woman with bilateral bullous keratopathy (BK) was submitted to DSAEK surgeries in both eyes, first in right and after 6 months in left eye. CDVA was 20/160 in the right eye and 20/63 in the left eye. Corneal thickness evaluated by anterior segment optical coherence tomography was 569 µm in the right eye and 560 µm in the left eye. The root mean square (RMS) was 2.1 in the right and left eyes. Endothelial cell densities were not detectable in both eyes. The estimated precut donor graft thickness from eye bank was 250 and 40 µm in the right and in the left graft, respectively. Two years after surgery CDVA was 20/25 in both eyes. Corneal thickness was 633 µm with a lenticule thickness of 206 µm in the right eye and 439 µm with a lenticule thickness of 48 µm in the left eye. The RMS was 1.7 in the right eye and 1.4 in the left eye. Endothelial cell density was 2.272 cells/mm² in the right and 2.154 cells/mm² in the left eye.

Conclusion

DSAEK was safe and effective in the treatment of BK. In our report, the visual outcome resulted to be poorly related either to donor graft thickness or to postoperative corneal thickness.

Use of Ozone-Based Eye Drops: A Series of Cases in Veterinary and Human Spontaneous Ocular Pathologies

Conjunctivitis, keratoconjunctivitis, and corneal ulcers are common eye disorders frequently diagnosed in both humans and animals, and are currently treated by topical administration of eye drops containing anti-inflammatory and antibacterial agents. The current molecules often lack efficacy because infections in hypoxic tissue contain methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa; thus, new products for the treatment of ocular pain and inflammation are needed. The use of ozone, a molecule stabilized for topical use as an ozonide, could be providential due to its anti-inflammatory and bactericidal activity in certain anterior segment pathologies, in addition to promoting tissue repair properties. Ozonated oils have the same properties as gaseous ozone and are well tolerated by tissues. In the present study the repair and regeneration effect of ozonated oil in liposomes plus hypromellose (Ozodrop®, FB Vision, Ascoli Piceno, Italy) instilled 3–4 times a day in external ocular spontaneous pathologies both in animals and humans are reported.

Corneal stromal demarcation line after collagen cross-linking in corneal ectatic diseases: a review of the literature

Collagen cross-linking (CXL) is a relatively new conservative approach for progressive corneal ectasia, which is able to strengthen corneal tissue reforming new covalent bonds. Subjective and objective results following this method seem to be promising. In recent years, newer CXL protocols have been developed to perform more effective and less invasive procedures. The increasing diffusion of CXL in the corneal ectatic disease has increased the need to have actual indices regarding the efficacy of the treatment. Evaluation of demarcation line (DL), a transition zone between the cross-linked anterior corneal stroma and the untreated posterior corneal stroma, is considered a measurement of the depth of CXL treatment into the stroma. Some evidence in the literature emphasize that DL could be a measure of effectiveness of the CXL. On the contrary, some authors believe that the “the deeper, the better” principle is rather a simplistic approach for interpreting the clinical importance of the corneal stromal DL.

Trattamento endoscopico della calcolosi ureterale

Non-invasive techniques have revolutionized the treatment of ureteral stones. We report the success rate and the complication rate of ureteral calculosis treatment with ureterorenoscopy. From November 1990 to April 1994 we have treated 121 patients with URS. In all cases we have used a 12.5 F. “Wolf” rigid ureteroscope. 85 patients (70.2%) were treated with ultrasonic lithotripsy; 36 (29.7%) with a Dormia basket; and in 16 cases a combined treatment of both procedures was employed. Complete stone removal was obtained in 96 patients (79.3%) but six of these required further endoscopic treatment. The complication rate was 7.4 per cent (9 patients) and two patients (1.6%) needed open surgery. In our experience ureteroscopy is a good approach to the treatment of ureteral stones.