-
The British Journal of Ophthalmology Nov 2023To investigate the association between the backward configuration of the peripapillary sclera (PPS), measured as PPS angle (PPSA), and presence and extent of...
AIMS
To investigate the association between the backward configuration of the peripapillary sclera (PPS), measured as PPS angle (PPSA), and presence and extent of parapapillary gamma zone.
METHODS
Out of the population-based Beijing Eye Study 2011, we randomly selected individuals free of optic nerve and retinal diseases. With Spectralis optical coherence tomography, we measured gamma zone (zone free of Bruch's membrane (BM)) and determined the PPSA, defined as the angle between the anterior scleral surface lines from both sides of the optic nerve head (ONH).
RESULTS
The study included 678 individuals with age of 59.5±7.6 years (range: 50-90) and axial length of 23.5±1.3 mm (20.9-29.2). Gamma zone was more prevalent in eyes with larger PPSA (p=0.006) after adjustment for axial length (p<0.001) and BM opening area (p<0.001). Gamma zone width was positively associated with PPSA, axial length and BM opening area (all p<0.001) in multivariable analysis. Circular gamma zone was accompanied with larger PPSA as compared with focal gamma zone (19.9°±7.2° vs 6.3°±5.3°, p<0.001). Focal temporal gamma and focal inferior gamma had similar mean PPSA (p=0.69). However, the horizontal PPSA was significantly larger than the vertical PPSA in inferior gamma (6.9°±6.3° vs 4.7°±6.6°; p=0.005), while they were comparable in temporal gamma (6.1°±5.8° vs 6.3°±6.4°; p=0.073).
CONCLUSIONS
A more backward bowing of the PPS was linearly and spatially associated with the presence, size and extent of gamma zone. It suggested that the BM and the sclera were closely related in participating the biomechanical behaviour of the ONH.
Topics: Humans; Middle Aged; Aged; Aged, 80 and over; Sclera; Beijing; Axial Length, Eye; Optic Disk; Bruch Membrane; Tomography, Optical Coherence
PubMed: 36126108
DOI: 10.1136/bjo-2022-321868 -
3D imaging of aqueous veins and surrounding sclera using a dual-wavelength photoacoustic microscopy.Biomedical Optics Express Dec 2023Understanding aqueous outflow resistance at the level of aqueous veins has been a challenge to the management of glaucoma. This study investigated resolving the...
Understanding aqueous outflow resistance at the level of aqueous veins has been a challenge to the management of glaucoma. This study investigated resolving the anatomies of aqueous veins and the textures of surrounding sclera using photoacoustic microscopy (PAM). A dual wavelength PAM system was established and validated using imaging phantoms, porcine and human globes perfused with an optical contrast agent . The system shows lateral resolution of 8.23 µm and 4.70 µm at 1200 nm and 532 nm, respectively, and an axial resolution of 27.6 µm. The system is able to separately distinguish the aqueous veins and the sclera with high contrast in full circumference of the porcine and human globes.
PubMed: 38420307
DOI: 10.1364/BOE.505288 -
Journal of Materials Chemistry. B Mar 2024Pathologic myopia has seriously jeopardized the visual health of adolescents in the past decades. The progression of high myopia is associated with a decrease in...
Pathologic myopia has seriously jeopardized the visual health of adolescents in the past decades. The progression of high myopia is associated with a decrease in collagen aggregation and thinning of the sclera, which ultimately leads to longer eye axis length and image formation in front of the retina. Herein, we report a fibroblast-loaded hydrogel as a posterior scleral reinforcement (PSR) surgery implant for the prevention of myopia progression. The fibroblast-loaded gelatin methacrylate (GelMA)-poly(ethylene glycol) diacrylate (PEGDA) hydrogel was prepared through bioprinting with digital light processing (DLP). The introduction of the PEGDA component endowed the GelMA-PEGDA hydrogel with a high compression modulus for PRS surgery. The encapsulated fibroblasts could consistently maintain a high survival rate during 7 days of incubation, and could normally secrete collagen type I. Eventually, both the hydrogel and fibroblast-loaded hydrogel demonstrated an effective shortening of the myopic eye axis length in a guinea pig model of visual deprivation over three weeks after implantation, and the sclera thickness of myopic guinea pigs became significantly thicker after 4 weeks, verifying the success of sclera remodeling and showing that myopic progression was effectively controlled. In particular, the fibroblast-loaded hydrogel demonstrated the best therapeutic effect through the synergistic effect of cell therapy and PSR surgery.
Topics: Animals; Guinea Pigs; Disease Models, Animal; Sclera; Hydrogels; Myopia; Fibroblasts; Printing, Three-Dimensional
PubMed: 38362614
DOI: 10.1039/d3tb02548a -
Seminars in Ophthalmology Jan 2024Cicatricial lower eyelid retraction is a challenging condition. It involves scarring of the lower eyelid, which causes it to retract and expose the sclera. This can lead... (Review)
Review
BACKGROUND
Cicatricial lower eyelid retraction is a challenging condition. It involves scarring of the lower eyelid, which causes it to retract and expose the sclera. This can lead to complications such as dry eye syndrome and corneal melting. It can be caused by trauma, burns, or previous eyelid surgery. Detailed assessment and understanding of eyelid anatomy and retraction are critical for successful surgical planning. Dynamic and static examinations of the eyelid including measurements of the lower eyelid margin reflex distance (MRD2) and scleral show are also essential to determine the appropriate treatment approach.
METHODS
A systematic review was conducted using Medline, Scopus, and Cochrane databases with keywords related to cicatricial lower eyelid retraction. The publication language was limited to English after 2000. A total of 29 articles were included for data extraction and analysis.
RESULTS
The main surgical techniques include tarsoconjunctival grafts, spacers, midface lift, and lateral canthal tendon suspension, although no single procedure has been universally recognized as the gold standard. New innovations such as synthetic grafts and xenografts are being explored for their potential in eyelid reconstruction. Severe cases, defined as those with inferior scleral show greater than 2 mm, may require a combination of reconstruction methods.
CONCLUSIONS
Correcting cicatricial lower eyelid retraction is a major challenge in oculoplastic reconstruction. The surgical approach should be individualized, considering the pathologies and etiologies of lid retraction. In-depth knowledge and careful surgical planning are essential for best outcomes. There is no gold standard technique, and postoperative outcomes, complications, and management vary depending on the surgical approach used.
Topics: Humans; Eyelids; Eyelid Diseases; Blepharoplasty; Corneal Ulcer; Retrospective Studies
PubMed: 37904540
DOI: 10.1080/08820538.2023.2273850 -
International Ophthalmology Mar 2024To evaluate the thickness of anterior sclera and corneal layers in patients with systemic sclerosis.
PURPOSE
To evaluate the thickness of anterior sclera and corneal layers in patients with systemic sclerosis.
METHODS
The present cross-sectional study included 41 patients with systemic sclerosis and 41 age- and gender-matched healthy controls. The study and control groups were compared in terms of the thickness of anterior sclera, corneal epithelium, Bowman's layer, corneal stroma, and Descemet's membrane-endothelium complex. The thickness measurements were obtained using the anterior segment module of spectral-domain optical coherence tomography.
RESULTS
The thickness of anterior sclera, corneal epithelium, Bowman's layer, and Descemet's membrane-endothelium complex were similar in the patients with systemic sclerosis and healthy controls (P > 0.05). Total corneal thickness at the apex was 511.1 ± 33.5 µm in the systemic sclerosis group and 528.4 ± 29.5 µm in the control group (P = 0.015). The corneal stroma was thinner in the systemic sclerosis patients compared to the healthy controls (P = 0.02).
CONCLUSIONS
The corneal stroma was thinner in the patients with systemic sclerosis compared to that of healthy controls, while the thickness of the anterior sclera was similar in both groups.
Topics: Humans; Sclera; Cross-Sectional Studies; Cornea; Epithelium, Corneal; Corneal Stroma; Tomography, Optical Coherence
PubMed: 38489070
DOI: 10.1007/s10792-024-03013-z -
Diagnostics (Basel, Switzerland) Jan 2024Since its introduction, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and has now become an indispensable, noninvasive tool in daily... (Review)
Review
Since its introduction, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and has now become an indispensable, noninvasive tool in daily practice. Most ophthalmologists are familiar with its use in the assessment and monitoring of retinal and optic nerve diseases. However, it also has important applications in the assessment of anterior segment structures, including the cornea, conjunctiva, sclera, anterior chamber, and iris, and has the potential to transform the clinical examination of these structures. In this review, we aim to provide a comprehensive overview of the potential clinical utility of anterior segment OCT (AS-OCT) for a wide range of anterior segment pathologies, such as conjunctival neoplasia, pterygium, scleritis, keratoconus, corneal dystrophies, and infectious/noninfectious keratitis. In addition, the clinical applications of AS-OCT (including epithelial mapping) in preoperative planning and postoperative monitoring for corneal and refractive surgeries are discussed.
PubMed: 38248000
DOI: 10.3390/diagnostics14020122 -
Retina (Philadelphia, Pa.) Oct 2023The mean change in best-corrected visual acuity (BCVA), intraocular pressure, and endothelial cell counts after intraocular lens (IOL) implantation and the incidence... (Meta-Analysis)
Meta-Analysis
PURPOSE
The mean change in best-corrected visual acuity (BCVA), intraocular pressure, and endothelial cell counts after intraocular lens (IOL) implantation and the incidence rate of postoperative complications were estimated by systematic review and meta-analysis to assess the surgical and refractive outcomes of the sutureless scleral fixation Carlevale IOL.
METHODS
A literature search was conducted using PubMed, Embase, and Scopus. The weighted mean difference (WMD) was used to present the mean change in BCVA, intraocular pressure, and endothelial cell count after IOL implantation, whereas a proportional meta-analysis was used to estimate the pooled incidence rate of postoperative complications.
RESULTS
In the meta-analysis of 13 studies involving 550 eyes, the pooled WMD of the mean change in BCVA showed a significant improvement in BCVA in patients who underwent Carlevale IOL implantation (WMD = 0.38, 95% confidence interval: 0.30-0.46, P < 0.001; heterogeneity [I 2 ] = 52.02%). The subgroup analyses indicated that the mean change in BCVA was not significantly higher according to the last follow-up visit, with no statistically significant subgroup effect ( P = 0.21) (WMD up to 6 months: 0.34, 95% confidence interval: 0.23-0.45, I 2 = 58.32%, WMD up to 24 months: 0.42, 95% confidence interval: 0.34-0.51, I 2 = 38.08%). In the meta-analysis of 16 studies involving 608 eyes, the pooled incidence rate of postoperative complications was equal to 0.22 (95% confidence interval: 0.13-0.32, I 2 = 84.87, P ≤ 0.001).
CONCLUSION
Carlevale IOL implantation represents a reliable method of restoring vision in eyes with missing capsular or zonular support.
Topics: Humans; Lens Implantation, Intraocular; Visual Acuity; Lenses, Intraocular; Refraction, Ocular; Sclera; Postoperative Complications; Retrospective Studies; Suture Techniques
PubMed: 37399540
DOI: 10.1097/IAE.0000000000003873 -
Journal of AAPOS : the Official... Oct 2023Neonatal retinal hemorrhage is a common finding in newborns, but the underlying mechanisms are not fully understood. A computational simulation was designed to study the...
PURPOSE
Neonatal retinal hemorrhage is a common finding in newborns, but the underlying mechanisms are not fully understood. A computational simulation was designed to study the events taking place in the eye and orbit when the head is compressed as the neonate passes through the birth canal.
METHODS
A finite element model of the eye, optic nerve sheath, and orbit was simulated and subjected to forces mimicking rises in intracranial pressure (ICP) associated with maternal contractions during normal vaginal delivery. Resulting changes in intraocular pressure (IOP), pressure in the optic nerve sheath, and stress within the sclera and retina were measured.
RESULTS
During contractions, increased ICP was transmitted to the orbit, globe, and optic nerve sheath. IOP rose by 2.71 kPa near the posterior pole. Pressure at the center of the optic nerve sheath rose by 7.31 kPa and up to 9.30 kPa at its interface with the sclera. Stress in the retina was highest near the optic disk and reached 10.93, 10.99, and 13.28 kPa in the preretinal, intraretinal, and subretinal layers, respectively. Stress in the sclera peaked at 12.76 kPa.
CONCLUSIONS
Increasing ICP associated with natural vaginal delivery increases intraorbital pressure, which applies stress to the retina. Associated retinal deformation may cause tearing of the retinal vasculature. Increased pressure within the optic nerve sheath may occlude the central retinal vein, resulting in outflow obstruction and subsequent rupture. Forces accumulated near the optic disk, likely accounting for the tendency of neonatal retinal hemorrhage to occur posteriorly.
Topics: Female; Humans; Infant, Newborn; Retinal Hemorrhage; Optic Disk; Retina; Intraocular Pressure; Retinal Vessels
PubMed: 37722620
DOI: 10.1016/j.jaapos.2023.07.013 -
Retina (Philadelphia, Pa.) Sep 2023The sclera is reportedly thicker in eyes with central serous chorioretinopathy (CSC) than in healthy control eyes. We compared the scleral thicknesses of the affected...
PURPOSE
The sclera is reportedly thicker in eyes with central serous chorioretinopathy (CSC) than in healthy control eyes. We compared the scleral thicknesses of the affected and unaffected fellow eyes of patients with unilateral CSC.
METHODS
We retrospectively examined the findings of 115 patients with unilateral CSC. Comparisons of the spherical equivalent, axial length, anterior chamber depth, subfoveal choroidal thickness, scleral thickness, and presence of peripheral ciliochoroidal effusion of the affected and fellow eyes were made. Using anterior segment optical coherence tomography, scleral thickness was measured vertically, 6 mm posterior to the scleral spur in the superior, temporal, inferior, and nasal directions.
RESULTS
No significant differences in scleral thickness in all four directions, spherical equivalent, axial length, anterior chamber depth, and frequency of ciliochoroidal effusion were found between the affected and unaffected fellow eyes. The only significant difference between the affected and fellow eyes was observed in the subfoveal choroidal thickness (398.8 µ m vs. 346.6 µ m, P < 0.001).
CONCLUSION
A thickened choroid seems to have a direct effect on CSC development. By contrast, the affected and fellow eyes showed no significant difference in scleral thickness, indicating that scleral thickening may be a predisposing factor for the development of CSC.
Topics: Humans; Central Serous Chorioretinopathy; Retrospective Studies; Sclera; Fluorescein Angiography; Choroid; Tomography, Optical Coherence; Choroidal Effusions
PubMed: 37262427
DOI: 10.1097/IAE.0000000000003850 -
Journal of Cataract and Refractive... Aug 2023
Topics: Humans; Polypropylenes; Prosthesis Design; Sclera; Lenses, Intraocular
PubMed: 37276264
DOI: 10.1097/j.jcrs.0000000000001234