Scleral Wall Research Articles

Microforceps-Assisted Transscleral Fixation of Intraocular Lens.

We present a novel technique for intraocular lens (IOL) fixation. The technique can be used on single-piece acrylic IOLs and can manage the patients who are either aphakia or with a dislocated IOL. One end of Gore-Tex suture is tied into the optic-haptic junction of the IOL. Another end is fixated in the scleral wall. The single sclerotomy and double sclerotomies settings can be applied to different situations. Twelve eyes received this procedure. After a follow-up period of up to 20 months, the IOLs were well centered. The technique is a reliable method for scleral fixation of IOLs, which can be applied on the widely used single-piece acrylic IOLs. In our experience, it is reproducible and rarely cause complications.

RELAY INTRASCLERAL 6-0 POLYPROPYLENE-ASSISTED INTRAOCULAR LENS FIXATION: A Retrospective Comparison With Modified Yamane Technique.

To describe a new surgical technique that uses a relay suture to optimize sutureless scleral fixation of intraocular lens in eyes with capsular insufficiency and to evaluate the outcomes of this technique versus Flanged, double needle-guided, scleral fixation of intraocular lens with haptic trimming (modified Yamane approach). Relay intrascleral 6-0 polypropylene sutures with flanges generated at the intraocular ends were used to fixate and securely hold a rigid intraocular lens with haptic eyelets against the inner scleral wall. The results were analyzed at 3-, 6-, and 12-month follow-up. This retrospective cohort study found that compared with the control group (n = 27), the relay-sutured group (n = 26) had greater mean changes in corneal astigmatism (0.44 vs. -0.52 diopters [D]) and fewer mean degrees of intraocular lens astigmatism (0.62 vs. 1.1 D). The mean intraocular lens decentration was comparable between both the groups; however, in the control group, there was a significant increase in intraocular lens tilt degrees from 3 to 12 months. Moreover, significantly higher proportions of patients with persistent macular edema and iris-optic capture were seen in the control group. The relay-sutured technique may be an alternative to flapless scleral fixation of intraocular lens and provides a stable intraocular lens position with acceptable complication rates.

Preclinical Investigation of Ab Interno Goniotomy Using Three Different Techniques.

To evaluate incisional or excisional tissue-level effects of ab interno goniotomy techniques on human trabecular meshwork (TM). The TM from human cadaveric corneal rim tissue was treated using three devices: (1) Kahook Dual Blade (KDB) GLIDE, (2) iAccess, and (3) SION. Two human corneal rims were used for each of the iAccess and SION devices and one with the KDB GLIDE, with 360 degrees of TM treated in each case. Sections were then prepared for analysis and comparison between devices. Tissue samples underwent standard histologic processing with H&E stain, followed by comparative analyses. Areas treated with the KDB GLIDE device resulted in nearly complete excision of TM overlying the canal of Schlemm without injury to surrounding tissues. The iAccess device can be used as a focal trephine to create holes or dragged for TM disruption. When used to create holes, iAccess punched through the full thickness of the TM and also disrupted the anterior scleral tissue. It caused some incisional openings through the TM but with significant leaflets remaining and minimal true "hole-punch" effect. When the device tip was dragged, iAccess incised the TM and left debris behind with little, if any, excision of tissue. SION led to both incision and excision of TM with incision predominating over excision. The various methods evaluated to perform ab interno goniotomy resulted in varying degrees of TM incision or excision. Only the KDB GLIDE device resulted in reliable excision of TM, while the other devices produced incision or minimal excision of tissue with residual leaflets and debris. Use of iAccess resulted in focal disruption of the anterior scleral wall. Because incisional approaches that leave longer residual leaflets may be more prone to fibrosis and closure compared to excisional treatments, clinical correlation will be necessary to better understand the significance of these findings with respect to relative effectiveness of intraocular pressure lowering in eyes with glaucoma.

Posterior scleritis following COVID-19 vaccination or infection simulating uveal melanoma in 8 consecutive patients.

To determine clinical features and outcomes of posterior scleritis masquerading as uveal melanoma following vaccination against COVID-19 and/or COVID-19 infection. All patients with posterior scleritis referred to our service to rule out intraocular tumour between February 2021 and June 2022, who previously had COVID-19 vaccination and/or infection (n = 8). A retrospective detailed review of patient charts and imaging was carried out. Previous COVID-19 vaccination was documented in 6 patients (75%) and previous COVID-19 infection and vaccination in 2 patients (25%). Demographic features included mean age of 59 years (median 68, range 5-86 years), white race (n = 7, 87%), and male sex (n = 5, 63%). Mean visual acuity at presentation was 0.24 LogMAR (median 0.18, range 0.0-0.70). The main presenting symptom was blurred vision with pain (n = 5, 63%). Features that suggested scleritis and not uveal melanoma included pain (n = 6, 75%), anterior scleritis (n = 3, 38%), disc oedema (n = 1, 13%), choroidal detachment (n = 3, 38%), choroidal folds (n = 3, 38%), diffusely thickened scleral wall on ultrasonography (n = 2, 25%), Tenon's oedema (n = 5, 63%), and scleral nodule with medium/high internal reflectivity on ultrasonography (n = 4, 50%). Follow-up information at mean of 2 months (range 0.25-7 months) revealed visual acuity at date last seen was mean 0.30 LogMAR (median 0.29, range 0.0-0.54). By 2 months, resolution of "tumour" was noted in 5/6 (83%) patients with follow-up. Posterior scleritis following COVID-19 vaccination and/or infection can masquerade as choroidal melanoma. At 2 months duration, partial or complete resolution of features with minimal visual consequence was noted.

RISK FACTORS AND SURGICAL APPROACH FOR PARS PLANA VITRECTOMY OF POSTERIORLY DISLOCATED INTRAOCULAR LENSES

The retrospective study was conducted in the Department of Ophthalmology, Nishtar Medical Hospital, and Bakhtawar Amin Trust Hospital from January 2022 to January 2023 to evaluate risk factors and surgical approach for posterior dislocation of the intraocular lens into vitreous requiring pars plana vitrectomy. A total of 30 eyes of 30 patients (20 male and 10 female) were included in the study. Standard PPV vitrectomy was performed in all patients. The Iris fixation technique was used in patients having a 3-piece lens design. A sclera fixation technique was performed to secure the lens and prevent it from falling onto the retina. IOL (Intra-Ocular Lens) was exchanged in eyes in which it was previously damaged. Results showed that in 28 (93.3%) eyes, the original lens was conserved and positioned on the scleral wall, iris, or both. The existing lens could not be preserved in 2(6.6%) eyes. 92.1% of cases had a single risk factor for IOL dislocation. After surgery, uncorrected visual acuity (UCVA) improved from 20/400 on the initial visit to 20/80 on the final (P=0.001). UCVA remained unchanged in 3 (10%) patients and improved in 27 (90%) patients. It can be concluded that the incidence of posterior IOL dislocation has been increasing. Intravitreal substance injections, myopia, and previous vitrectomy are the major risk factors. In most cases, the existing lens can be preserved and secured in the posterior chamber through pars plana vitrectomy.

Delayed reorganisation of F-actin cytoskeleton and reversible chromatin condensation in scleral fibroblasts under simulated pathological strain

Mechanical loading regulates the functional capabilities of the ocular system, particularly in the sclera (‘white of the eye’) – the principal load-bearing tissue of the ocular globe. Resident fibroblasts of the scleral eye wall are continuously subjected to fluctuating mechanical strains arising from eye movements, cerebrospinal fluid pressure and, most influentially, intra-ocular pressure (IOP). Whilst fibroblasts are hypothesised to actively participate in scleral biomechanics, to date limited information has been reported on how the macroscopic stresses and strains are transmitted via their cytoskeletal networks. In this study, the effect of applying either a ‘physiological load’ (simulating healthy IOP) or a ‘pathological load’ (simulating an elevated glaucomatous IOP) to bovine scleral fibroblasts, as a model of human glaucoma, was conducted to characterise cytoskeletal organisation, chromatin condensation and cell dimensions using immunofluorescence confocal microscopy. Quantification of cell parameters and cytoskeletal element anisotropy were subsequently performed using FibrilTool, and chromatin condensation parameter assessment through a bespoke MATLAB script. The novel findings suggest that physiological load-induced F-actin rearrangement is transient, whereas pathological load, recapitulating in vivo glaucomatous IOP levels, had a reversible and inhibitory influence on remodelling of the cytoskeletal architecture and, further, induction of chromatin condensation. Ultimately, this could compromise cell behaviour. These findings could provide valuable insight into the mechanism(s) used by scleral fibroblasts to mechanically adapt to support biomechanical tissue integrity, and how it could be potentially modified for therapeutic avenues targeting mechanically mediated ocular pathologies such as glaucoma.

Femtosecond Laser Combined with Double-Flange Polypropylene Suture Capsular Tension Ring Suspension for the Treatment of Subluxation of Lens in Marfan Syndrome

Purpose To evaluate the use of femtosecond laser combined with double-flange polypropylene suture capsular tension ring (CTR) suspension to treat subluxation of lens in Marfan syndrome. The objective is to provide safer and more effective surgical procedures for patients. Setting. Eye Hospital, Aier Eye Hospital of Wuhan University, Wuhan, China Methods In this retrospective study, we observed sixteen patients (16 eyes) with Marfan syndrome who had undergone this operation. Femtosecond laser incision was performed on the anterior capsule with the lens as the center. The suspending CTR was clipped to anterior capsule to support it, which was secured to the sclera with a double-flange polypropylene suture. Uncorrected visual acuity (UCVA), intraocular pressure (IOP), tilt, and decentration of the intraocular lens (IOL) and postoperative complications were evaluated. Results All 16 patients were successfully implanted with suspended CTR and IOL after femtosecond laser assisted surgery. Visual acuity improved significantly after surgery (p < 0.01). At 1 month, 3 months and 6 months postoperatively, the tilt of the IOL was 2.70 ± 0.934, 2.65 ± 0.897, and 2.66 ± 0.781, and the decentration of the IOL was 0.30 ± 0.770, 0.30 ± 0.682, and 0.29 ± 0.737; both had no statistically significant difference between the three groups. After the operation, 4 patients had hyphema and 2 patients experienced a temporary postoperative IOP increase. Only one flange was exposed one month after operation and recovered right after secondary adjustment. Conclusion Femtosecond laser combined with double-flange polypropylene suture CTR suspension was effective in fixing the lens capsule to the scleral wall in cases of subluxation of lens seen in Marfan syndrome during our short-term observation. The long-term efficacy of this operation needs further observation and follow-up.

Second-generation capsular anchor for subluxated lenses: first clinical results.

To evaluate the use of the second-generation capsular anchor in the treatment of subluxated crystalline and synthetic intraocular lenses. Department of Ophthalmology, Meir Medical Center, Kfar Saba, Israel. Prospective interventional study. This study evaluated the second-generation capsular anchor, a 3D poly(methyl methacrylate) intraocular implant designed to anchor the lens capsule to the sclera. All surgeries were performed by a single surgeon. Intraoperative and postoperative complications were recorded. Corrected distance visual acuity, lens centration, and lens tilt were assessed at the final follow-up of 3 months. 10 eyes of 10 patients were included in this study. Mean age was 56.2 (22 to 87) years. The reasons for the lack of zonular support were pseudoexfoliation in 3 cases, trauma in 3 cases, and Marfan, ectopia lentis, and pathologic myopia (1 case each). In 1 case, pseudoexfoliation and a history of recent trauma coexisted. 8 of the 10 surgeries were due to subluxation of crystalline lenses and 2 due to subluxation of intraocular lenses. Vision improved in all patients after surgery. Centration of the IOLs was excellent in all patients at the third postoperative month. One patient developed a retinal detachment at the third postoperative week and underwent successful surgery, and 1 patient developed macular edema at the fifth postoperative month, which resolved with topical medication. The second-generation capsular anchor, designed to provide significant improvements over the first-generation device, is effective in fixating the capsular bag to the scleral wall in cases with inadequate capsular support.

Enhanced surgical technique for sutureless intrascleral fixation of intraocular lenses.

A simplified intrascleral fixation technique involving implantation of the Carlevale intraocular lens (IOL) in the posterior chamber is described, which lodges the T-shaped IOL haptics in the scleral wall, not requiring scleral flaps. This surgical modification reduces operative time, limits iatrogenic damage to the sclera, and avoids friction between haptics and the conjunctiva, which may cause conjunctival erosion and infection in the long term. 13 patients with crystalline lens or IOL dislocation/subluxation had surgery to implant the Carlevale IOL in the posterior chamber. Mean corrected distance visual acuity preoperatively was 0.75 ± 0.5 logMAR (range, 0.2 to 1.5 logMAR) and improved to 0.28 ± 0.3 logMAR (range, 0 to 1.0 logMAR) postoperatively. Complications rarely occurred and were not sight-threatening. The sutureless scleral fixation of the Carlevale IOL using the modified surgical technique may represent a safe and effective procedure to restore visual function in patients with damaged zonular-capsular support.

A Non-expected and Extreme Complication of Phacoemulsification: Scleral Wall Rupture

Rupture of the scleral wall during intraocular surgeries is extremely rare even in patients with a history of trauma, underlying ocular or systemic autoimmune disease. In this report, we describe a single case of a partial scleral wall rupture during phacoemulsification. We aim to discuss this extreme complication and to highlight the importance of a trauma history before phacoemulsification. An 84-year-old patient was hospitalized with the plan of phacoemulsification surgery. During phacoemulsification, conjunctival chemosis appeared all around the limbus and subconjunctival hemorrhage at nasal side. After conjunctival dissection, partial scleral rupture was detected. Iris-choroid were expelled from the wound. Phacoemulsification was immediately stopped and wound was closed primarily. There were no signs or symptoms of prior inflammation, and rheumatologic workup was negative. Nevertheless, the patient had an old ocular blunt trauma history. During the examination of a patient with a trauma history, scleral wall structure should not be overlooked. Weakness in scleral wall could lead to detrimental complications during intraocular surgeries.

Application of trigonometric function to calculate the safe movement angle of cannula in 23G double-channel silicone oil removal

AIM: To explore the safe movement angle of a 23-gauge (G) cannula in double-channel silicone oil (SO) removal surgery. METHODS: From March 2017 to September 2017, 15 patients with SO filled eyes were enrolled in this retrospective analysis. Based on ultrasound biomicroscopy (UBM), the distance from the front surface of the sclera at the 2 o’clock and the 10 o’clock positions to the SO bubble at 4 mm behind the corneal limbus was measured and defined as “A”. The length of the 23G cannula (4 mm) was defined as “C”. The width of the scleral inner wall at the maximum operating angle of the scleral trocar was defined as “B”. The safe movement angle of the 23G cannula was determined according to the trigonometric function table. Using the self-made SO removal device connected to the 23G puncture cannula, the SO was successfully removed from all patients. RESULTS: The average SO removal time for all patients was 4.78±0.13min. The trigonometric function was used to work out the distance from the scleral front surface to the SO bubble, which was 0.82-2.81 mm (1.62±0.41 mm) at the 2 o’clock position, and 0.98-2.19 mm (1.71±0.34 mm) at the 10 o’clock position. Finally, the verification analysis using geometric model calculation showed that the optimal movement angle of the cannula was 52°. CONCLUSION: Combining the trigonometric function and UBM measurement to calculate the safe movement angle of a 23G cannula can effectively guide the moving range of the trocar during SO removal. A movement angle of the cannula larger than 50° may avoid the occurrence of a retinal tear.

Preclinical Investigation of Goniotomy Using Four Different Techniques.

PurposeTo evaluate the tissue-level effects of goniotomy techniques on human trabecular meshwork (TM).DesignLaboratory investigation.MethodsThe TM from human cadaveric corneal rim tissue was treated using 4 techniques: (1) microvitreoretinal (MVR) blade; (2) 360° trabeculotomy with 5-0 prolene suture; (3) the Kahook Dual Blade (KDB) Glide® device; (4) TrabEx™ device; tissue samples underwent standard histologic processing with H&E stain followed by comparative analyses.ResultsThe MVR blade exhibited incision of TM extending into the scleral wall. The TrabEx device removed a small portion of TM with large leaflet tissue remnants in all treated areas. 360° suture trabeculotomy resulted in incision of the TM proximate to Schwalbe’s line with no excised tissue evident in all treated areas. Areas treated with the KDB Glide device resulted in nearly complete excision of TM without injury to surrounding tissues.ConclusionThe various methods used for performing goniotomy or trabeculotomy resulted in varying degrees of incision or excision of TM. Only the KDB Glide device resulted in reliable excision of TM with the other devices producing incision or variable excision of tissue. Clinical correlation is required to better understand the implications of the current findings when using these methods to lower intraocular pressure in eyes with glaucoma.

Suprachoroidal and Subretinal Injections of AAV Using Transscleral Microneedles for Retinal Gene Delivery in Nonhuman Primates

Retinal gene therapy using adeno-associated viruses (AAVs) is constrained by the mode of viral vector delivery. Intravitreal AAV injections are impeded by the internal limiting membrane barrier, while subretinal injections require invasive surgery and produce a limited region of therapeutic effect. In this study, we introduce a novel mode of ocular gene delivery in rhesus macaques using transscleral microneedles to inject AAV8 into the subretinal or suprachoroidal space, a potential space between the choroid and scleral wall of the eye. Using in vivo imaging, we found that suprachoroidal AAV8 produces diffuse, peripheral expression in retinal pigment epithelial (RPE) cells, but it elicited local infiltration of inflammatory cells. Transscleral subretinal injection of AAV8 using microneedles leads to focal gene expression with transduction of RPE and photoreceptors, and minimal intraocular inflammation. In comparison, intravitreal AAV8 shows minimal transduction of retinal cells, but elicits greater systemic humoral immune responses. Our study introduces a novel mode of transscleral viral delivery that can be performed without vitreoretinal surgery, with focal or diffuse transgene expression patterns suitable for different applications. The decoupling of local and systemic immune responses reveals important insights into the immunological consequences of AAV delivery to different ocular compartments surrounding the blood-retinal barrier.

Closure of Large Chronic Macular Hole by Scleral Imbrication and Retinal Expansion.

The purpose of this study is to describe a new technique for the treatment of large, chronic macular hole (MH) using scleral imbrication and retinal expansion and to report the outcomes of MH closure. This retrospective study demonstrates a procedure for correcting the disproportion between an area of stiff neurosensory retina and the inner scleral wall. Baseline MH parameters were collected. MH closure rate, visual outcomes, and biometry were reported at 6-month follow-up. MH closure was achieved in six out of seven patients (85.7%). Mean minimal hole diameter, base hole diameter, and MH index were 712 μm ± 136.8 μm, 1,440 μm ± 444 μm, and 0.27 μm ± 0.08 μm, respectively. At 6-month follow-up, median logarithm of the minimum angle of resolution (logMAR) corrected distance visual acuity significantly improved from 1.2 (interquartile range [IQR] = 1.0 to 1.6) preoperatively to 0.7 (IQR = 0.58 to 0.8) postoperatively (P = .018; Wilcoxon signed-rank test). This technique provided both satisfactory hole closure rates and acceptable structural outcomes. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e57-e64.].

Changes in conjunctival-scleral thickness after strabismus surgery measured with anterior segment optical coherence tomography.

To evaluate changes in conjunctival-scleral thickness following strabismus surgery with anterior segment optical coherence tomography (AS-OCT). Prospective, observational, consecutive case series. Distances between the conjunctival epithelium and inner scleral wall were measured with AS-OCT before and 3-5months after strabismus surgery. The measurements were performed at 1.5mm (limbus), 7.0mm (insertion), and 8.0mm (tendon) posterior to the scleral spur on the lateral rectus muscle (LR); and 1.5mm (limbus), 4.0mm (insertion), and 5.5mm (tendon) posterior to the scleral spur on the medial rectus muscle (MR). Thirty-three extraocular muscles (20 LRs and 13 MRs) from 23 subjects were studied. Thicknesses were significantly less at the insertion (0.95-0.78mm; p < 0.001) and tendon (0.99-0.78mm; p < 0.001) after LR recession and at the tendon (1.21-0.92mm; p = 0.02) after MR recession. Thicknesses were significantly greater at the insertion (0.82-1.07mm; p = 0.01) and tendon (0.95-1.28mm; p = 0.01) after MR resection or plication and at the limbus, insertion, and tendon (0.75-0.90mm, 0.94-1.19mm, 1.03-1.28mm, respectively; all p = 0.04) after LR resection or plication. Conjunctival-scleral thicknesses showed various changes after recession and resection or plication. These findings may help detect previous surgical operations when conjunctival scarring and ciliary vessel changes are unclear.

In-and-out technique for intraocular lens scleral fixation.

We describe a modified scleral fixation method to facilitate the good centration and adequate tension of sutures at both ends with addition of an internal fixation knot that reduces decentering of the IOL in a patient with postsurgical aphakia. Using an ab externo suture technique to fixate the haptics to the scleral wall, an additional loop knot is tied 1 mm next to the fixation knot at the haptic. In the technique, an internalized suture and an additional suture knot is tied while holding it close to the fixation knot at the haptic using a needle holder or McPherson forceps. The externalized sutures are secured by taking a bite of transclera and tying the suture to itself. This technique is simple and easy, and adds an internal check valve to prevent excessive pull and decentering of the intraocular lens at one side. The internal check valve also serves as a criterion for the point of fixation at each end.

Excessive scleral shrinkage, rather than choroidal thickening, is a major contributor to the development of hypotony maculopathy after trabeculectomy.

PurposeWe previously reported that eyes with hypotony maculopathy (HM) after trabeculectomy (TLE) exhibited more reduction of axial length (AL) than those without HM, suggesting that inward collapse of the scleral wall may contribute to the development of HM after TLE. However, we did not evaluate change in choroidal thickness (CT), which could influence AL measures. We compared the magnitude and rate of AL and CT changes in eyes with and without HM by simultaneously measuring these parameters before and after TLE.MethodsWe enrolled 77 eyes of 77consecutive patients with glaucoma, who underwent TLE between March 2014 and March 2016. Intraocular pressure (IOP), central corneal thickness, keratometry, AL, and CT were measured pre- and postoperatively, up to 6 months. These biometrics were compared in eyes with and without HM.ResultsThe 14 patients who developed HM were significantly younger than those who did not. The eyes with HM exhibited significantly reduced AL (2.8%) compared to those without HM (0.7%). There was no significant difference in CT change between the two groups. The rate of AL reduction was significantly correlated with age, postoperative IOP, and preoperative AL. Post-adjustment logistic regression analysis revealed that eyes with AL reduction rate ≥ 2% had 11.67 higher risk for developing HM (95% confidence interval, 1.28–106.6; P = 0.03).ConclusionsAL reduction rates ≥ 2% were significantly associated with HM. Excessive reduction in AL, which was seen in eyes with HM, was not an artificial measure resulting from choroidal thickening but rather reflected reductions in the anterior-posterior diameter of the eyeball. Inward collapse of the scleral wall leads to redundancy of the chorioretinal tissue, contributing to the development of HM after TLE.

Microstructural Crimp of the Lamina Cribrosa and Peripapillary Sclera Collagen Fibers.

PurposeAlthough collagen microstructural crimp is a major determinant of ocular biomechanics, no direct measurements of optic nerve head (ONH) crimp have been reported. Our goal was to characterize the crimp period of the lamina cribrosa (LC) and peripapillary sclera (PPS) at low and normal IOPs.MethodsONHs from 11 sheep eyes were fixed at 10-, 5-, or 0-mm Hg IOP and crimp periods measured manually from coronal cryosections imaged with polarized light microscopy (PLM). Using linear mixed-effect models, we characterized the LC and PPS periods, and how they varied with distance from the scleral canal edge.ResultsA total of 17,374 manual collagen crimp period measurements were obtained with high repeatability (1.9 μm) and reproducibility (4.7 μm). The periods were smaller (P < 0.001) and less variable in the LC than in the PPS: average (SD) of 13.8 (3.1) μm in the LC, and 31.0 (10.4) μm in the PPS. LC crimp period did not vary with distance from the scleral canal wall (P > 0.1). PPS period increased with the square root of the distance to the canal (P < 0.0001).ConclusionsSmall, uniform crimp periods within the sheep LC and immediately adjacent PPS may indicate that these tissues are setup to prevent large or heterogeneous deformations that insult the neural tissues within the canal. An increasing more variable period with distance from the canal provides a smooth transition of mechanical properties that minimizes stress and strain concentrations.

Collagen Architecture of the Posterior Pole: High-Resolution Wide Field of View Visualization and Analysis Using Polarized Light Microscopy.

PurposeThe purpose of this study was to leverage polarized light microscopy (PLM) to visualize the collagen fiber architecture of posterior pole and optic nerve head with micrometer-scale resolution and to identify and quantify major organizational components.MethodsEight sheep posterior poles were cryosectioned and imaged using PLM. Collagen fiber orientation was determined by using custom scripts, and the resulting orientation maps were inspected and quantified to identify major structural elements and tested for differences in mean fiber orientation and anisotropy, using linear mixed effect models.ResultsImages revealed an intricate organization of collagen fibers in the posterior pole. In the lamina cribrosa, interweaving fibers formed large knots and wrapped around nerve fiber pores, with beam insertions into the scleral canal wall that were either narrow and straight or wide. In the peripapillary sclera, three significantly different (P < 0.0001) components were identified: fibers oriented circumferentially proximal to the canal, radially in the innermost sclera, and unaligned with interweaving fibers. The radial fibers were between 60 and 180 μm thick, extending at least 3 mm from the canal.ConclusionsPLM revealed structural aspects of the lamina cribrosa and sclera that may have important biomechanical roles but that were previously unreported or not characterized quantitatively. In the lamina cribrosa, these roles included wide and narrow beam insertions and details of collagen fibers interweaving and wrapping around the pores. In the sclera, we described regions of circumferential, radial, and unaligned “random” fibers. Although there is consensus that circumferential fibers protect neural tissues by resisting canal expansion, the role of the radial fibers remains unclear.

Angle closure glaucoma – misleading causes, delayed treatment

We present the clinical case of a 43 years old female patient, referred to our clinic for a red, painful left eye. Multiple bilateral similar attacks were reported by the patient in the last 2 years, for which a diagnosis of conjunctivitis or anterior uveitis was established. At current presentation we found bilateral marked inflammatory reaction in the anterior segment (extensive peripheral iris synechiae, inflammatory membrane in the pupillary area, iris “bombe”, pigment dispersion, but no keratic precipitates or cells in the anterior chamber. Intraocular pressure (IOP) was 12 mmHg in OD and 40 mmHg in OS, under topical treatment, started 24 before the current visit. Gonioscopy showed closed angle in both eyes, “openable” in various grades after indentation in all quadrants. Anterior segment ocular coherence tomography (AS-OCT) and ultrasonic biomicroscopy (UBM) suggested anatomical causes for acute angle closure, revealing multiple rolling folds on the iris surface, high insertion onto the scleral wall. Multiple laboratory investigations excluded any potential cause of uveitis, therefore the anatomical theory remained in discussion related to a disproportion between anterior structures leading to angle closure attacks. We performed laser peripheral iridotomy, in this patient with positive outcome: IOP decrease, deepening of the AC, open angle in gonioscopy. Misleading issues in this case confused the initial diagnosis and delayed the adequate treatment.