Bulbar Conjunctival and Tenon's Layer Thickness Measurement using Optical Coherence Tomography

Ahmed Glaucoma Valve Implantation in Jordan: Indications and Complications

Aim

The main indications for Ahmed glaucoma valve (AGV) include neovascular glaucoma, congenital glaucoma, primary open angle glaucoma and patients with failed previous trabeculectomy. This article aims to investigate the complications of AGV in Jordanian glaucoma patients and to justify the main risk factors.

Methods

Retrospectively, we report 87 eyes of 83 patients who underwent AGV implantation for different indications. The database included demographic data, past ocular and medical history, the indication for surgery, the perioperative outcome parameters at different follow-up visits, and the developed complications at each post-operative visit.

Results

More than half of the patients (54%) were males. The mean age of the patients was 47.4 years. Neovascular glaucoma was the most common indication for AGV implantation. Valve encapsulation was the most encountered complication. About one quarter of the eyes at one time underwent valve revision. Younger patients, neovascular glaucoma and congenital glaucoma were associated significantly with AGV failure and for the need for revision surgery.

Conclusion

AGV is the predominant glaucoma surgery performed in Jordan. Valve encapsulation is the most common complication for AGV implant in Jordanian patients which may be related to racial and genetic factors. Neovascular glaucoma has a high burden in Jordan and secondary causes should be controlled adequately.

Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography

PURPOSE

To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT).

METHODS

We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and ≥70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected.

RESULTS

The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 ± 30 μm vs. 77 ± 16 μm; p < 0.001), as well as the superior and inferior quadrants (77 ± 16 μm vs. 86 ± 19 μm; p = 0.001). The mean episcleral thickness was larger in the superior (174 ± 54 μm) and inferior (141 ± 43 μm) quadrants, compared to the nasal (83 ± 38 μm) and temporal quadrants (90 ± 44 μm). The mean scleral thickness of the inferior quadrant was the largest (596 ± 64 μm), followed by the nasal (567 ± 76 μm), temporal (516 ± 67 μm) and superior (467 ± 52 μm) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 μm per age year (0.41-1.47 μm, p < 0.001).

CONCLUSIONS

This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall.

Tuck-in tenon patch graft for giant full-thickness macular holes

PURPOSE

To report the results of using autologous Tenon patch grafts for managing giant full-thickness macular holes (FTMHs) when other alternatives are not applicable.

METHODS

The same surgical technique was performed in all three cases. Briefly, a small fragment of Tenon's tissue was collected. The graft was introduced through a 23G trocar and released over the macular hole under a bubble of PFCL. The patch is delicately pushed towards the edges of the hole to slide underneath. The PFCL bubble is then actively aspirated next to the optic disc. Tamponade with gas or silicone oil is subsequently injected, with care taken to minimize fluid turbulence during the procedure.

RESULTS

The outcomes of autologous Tenon patch grafts in three giant FTMHs are reported. In the first case, silicone oil tamponade was injected, in the second, C2F6 gas was injected. And in the third case, that of a woman with advanced glaucoma, no tamponade was left in the eye. No adverse effects were observed during or after the procedures. Closure of the macular hole and functional improvement were documented during the follow-up period in all three cases.

CONCLUSION

With a follow-up of up to 6 months, the Tenon patch graft appeared to be a promising technique for managing complex cases of FTMH. Additional studies to investigate long-term outcomes and determine the most appropriate indications are warranted.

Machine learning-assisted prediction of trabeculectomy outcomes among patients of juvenile glaucoma by using 5-year follow-up data

OBJECTIVE

To develop machine learning (ML) models, using pre and intraoperative surgical parameters, for predicting trabeculectomy outcomes in the eyes of patients with juvenile-onset primary open-angle glaucoma (JOAG) undergoing primary surgery.

SUBJECTS

The study included 207 JOAG patients from a single center who met the following criteria: diagnosed between 10 and 40 years of age, with an IOP of >22 mmHg in the eyes on two or more occasions, open angle on gonioscopy in both eyes, with glaucomatous optic neuropathy, and requiring a trabeculectomy for IOP control. Only the patients with a minimum 5-year follow-up after surgery were included in the study.

METHODS

A successful surgical outcome was defined as IOP ≤18 mmHg (criterion A) or 50% reduction in IOP from baseline (criterion B) 5 years after trabeculectomy. Feature selection techniques were used to select the most important contributory parameters, and tenfold cross-validation was used to evaluate model performance. The ML models were evaluated, compared, and prioritized based on their accuracy, sensitivity, specificity, Matthew correlation coefficient (MCC) index, and mean area under the receiver operating characteristic curve (AUROC). The prioritized models were further optimized by tuning the hyperparameters, and feature contributions were evaluated. In addition, an unbiased relationship analysis among the parameters was performed for clinical utility.

RESULTS

Age at diagnosis, preoperative baseline IOP, duration of preoperative medical treatment, Tenon's thickness, scleral fistulation technique, and intraoperative mitomycin C (MMC) use, were identified as the main contributing parameters for developing efficient models. The three models developed for a consensus-based outcome to predict trabeculectomy success showed an accuracy of >86%, sensitivity of >90%, and specificity of >74%, using tenfold cross-validation. The use of intraoperative MMC and a punch for scleral fistulation compared to the traditional excision with scissors were significantly associated with long-term success of trabeculectomy.

CONCLUSION

Optimizing surgical parameters by using these ML models might reduce surgical failures associated with trabeculectomy and provide more realistic expectations regarding surgical outcomes in young patients.

A Review of Current Uses of Amniotic Membrane Transplantation in Ophthalmic Plastic and Reconstructive Surgery

PURPOSE

To review and summarize the existing literature on the clinical applications of amniotic membrane transplantation (AMT) in ophthalmic plastic and reconstructive surgery.

METHODS

A literature review was conducted on the PubMed database using the following search terms: "amniotic membrane" and "eyelid" or "orbit" or "fornix" or "socket" or "lacrimal".

RESULTS

In total 516 articles resulted from the search, of which 62 were included. Numerous cases and case series have been published on the use of amniotic membrane transplantation for ocular surface reconstruction, eyelid and forniceal reconstruction, and cicatricial eyelid abnormalities. Surgical methods of securing the graft vary. Few comparative studies exist; some show a similar or improved result when compared to oral mucous membrane grafting for certain indications.

CONCLUSIONS

Amniotic membrane transplantation can be a useful tool for the oculoplastic surgeon when faced with a case requiring reconstruction of the posterior lamellae, particularly in patients without other graft donor sites available, and uses of AMT continue to expand. Additional studies directly comparing AMT to other reconstructive techniques would be helpful in choosing between the available surgical techniques and standardizing best practices.

Comparison of Bleb Morphology following PRESERFLO® MicroShunt and Trabeculectomy Using Anterior Segment OCT

Trabeculectomy has traditionally been upheld as the gold standard in glaucoma surgery, but recent advancements, including the PRESERFLO® MicroShunt, have introduced less invasive techniques to mitigate complications and reduce intraocular pressure (IOP). The examination of bleb morphology post-filtering surgery is critical for modulating wound healing and ensuring long-term success. While previous evaluations of PRESERFLO-generated blebs have relied on data from trabeculectomy blebs, the differing surgical techniques used in PRESERFLO and trabeculectomy surgeries suggest potential variations in bleb morphologies. This study conducted a comparative analysis of blebs resulting from PRESERFLO and trabeculectomy procedures. Retrospective descriptive assessments using the Jenaer Bleb Grading System were performed, along with quantitative evaluation using eight-dimensional parameters utilizing anterior segment OCT. We included 93 eyes (57 following PRESERFLO, 36 following trabeculectomy). In the descriptive assessment, PRESERFLO-generated blebs exhibited fewer conjunctival cysts (3.5% vs. 22.2%, p = 0.007) and cavernous changes (10.5% vs. 30.5%, p = 0.021) compared to trabeculectomy. Quantitatively, overall bleb dimensions were comparable (maximal bleb height, width, and length, p > 0.05 for all). However, PRESERFLO blebs displayed a shallower (0.52 ± 0.24 vs. 0.67 ± 0.3 mm, p = 0.017) yet longer (4.12 ± 1.54 vs. 3.23 ± 1.64 mm, p = 0.024) episcleral lake. A thicker bleb wall (1.52 ± 0.46 vs. 1.10 ± 0.37 mm, p < 0.001) along with more posteriorly positioned blebs (distance to limbus = 6.16 ± 1.36 vs. 4.87 ± 1.34 mm, p < 0.001) were observed following PRESERFLO. This study illuminates the nuanced morphological differences between PRESERFLO and trabeculectomy blebs. Understanding these distinctions is vital, empowering clinicians to make informed postoperative decisions and avoid misinterpretation of bleb morphology.

Factors Correlated With Mid-Term Morphology of Functional Blebs Following Implantation of Preserflo MicroShunt Using AS-OCT

Purpose

Evaluating bleb morphology is crucial after glaucoma filtering surgery. Advances in anterior segment optical coherence tomography (AS-OCT) allow for objective assessment. While various parameters differentiate functional from failed blebs, limited information exists regarding variations within functional blebs. This study aimed to identify factors influencing morphology of functional blebs following implantation of Preserflo MicroShunt.

Methods

Eyes with functional blebs after Preserflo were retrospectively included. Age, gender, lens status, preoperative intraocular pressure (pre-IOP) and number of glaucoma medications were documented along with biometric measurements as axial length (AL), white-to-white distance, and anterior chamber depth. Postoperative data included time elapsed since surgery (TaS) and postoperative IOP (post-IOP). Bleb dimensions were measured using AS-OCT including maximal bleb height (MBH), width, length (MBL), bleb wall thickness (BWT), and bleb distance to limbus (DtL) along with dimensions of episcleral lake (maximal height, width [MLW], and length). Linear regression models were applied to correlate these parameters with bleb dimensions.

Results

Included were 50 eyes from 50 patients. Mean IOP decreased from 25.3 ± 10.0 to 11.9 ± 3.0 mm Hg after 278.5 ± 221.9 days after surgery. MBH correlated negatively with age (unstandardized coefficients [uSC] = -0.012) and TaS (uSC = -0.001, P = 0.008 for both). BWT correlated negatively with age (uSC = -0.013, P = 0.02), MBL with AL (uSC = -0.566, P = 0.01) and MLW with pre-IOP (uSC = -0.073, P = 0.02). DtL exhibited a positive correlation with post-IOP (uCS = 0.136, P = 0.02).

Conclusions

Morphology of functional blebs might be influenced by multiple factors such as age, TaS, AL, and pre- and post-IOP.

Translational Relevance

Age, time after surgery, axial length, and preoperative and postoperative IOP could affect the morphology of a functional bleb; hence, these factors should be taken into consideration when making treatment decisions.

Anterior segment optical coherence tomography in ocular surface tumours and simulating lesions

This study aims to systematically review the reported literature on the use of anterior segment optical coherence tomography (AS-OCT) in ocular surface tumours and simulating lesions. A systematic literature search was done using PubMed, Scopus, and Web of Science databases between January 2002 and December 2021. On AS-OCT, ocular surface squamous neoplasia typically demonstrate epithelial thickening, epithelial hyperreflectivity, and an abrupt transition between normal and abnormal epithelium. Conjunctival nevi usually show mildly hyperreflective epithelium of normal thickness, internal hyperreflectivity, and intralesional cysts which is the hallmark of this tumour. Primary acquired melanosis presents with normal thickness epithelium, basal epithelial hyperreflectivity, and absence of cysts. Conjunctival melanoma demonstrates hyperreflective normal/thickened epithelium, hyperreflective basal epithelium, internal hyperreflectivity, and absence of intralesional cysts. Conjunctival lymphoma shows homogenous, low-medium reflective subepithelial lesions with smooth borders, and dot-like infiltrates. Benign reactive lymphoid hyperplasia findings are similar to lymphoma but the infiltrates are more hyperreflective compared to lymphoma. Pterygium shows thickened conjunctival epithelium, epithelial hyperreflectivity, and subepithelial wedge-shaped hyperreflective tissue separated from the overlying epithelium by a cleavage plane. Pinguecula demonstrates mildly thickened epithelium and similar findings with pterygium but does not extend beyond the corneal limbus. This review shows that AS-OCT, as a noninvasive tool, has potential uses in the differential diagnosis of ocular surface tumours and simulating lesions. Major limitations of AS-OCT include limited visualization of the posterior border of thick, keratinized, and pigmented tumours and lack of assessment of large conjunctival tumours in a single cut.

Practice Patterns and Outcomes of Intravitreal Anti-VEGF Injection for Retinopathy of Prematurity: An International Multicenter Study

PURPOSE

To report practice patterns of intravitreal injections of anti-VEGF for retinopathy of prematurity (ROP) and outcomes data with a focus on retreatments and complications.

DESIGN

Multicenter, international, retrospective, consecutive series.

SUBJECTS

Patients with ROP treated with anti-VEGF injections from 2007 to 2021.

METHODS

Twenfty-three sites (16 United States [US] and 7 non-US) participated. Data collected included demographics, birth characteristics, examination findings, and methods of injections. Comparisons between US and non-US sites were made.

MAIN OUTCOME MEASURES

Primary outcomes included number and types of retreatments as well as complications. Secondary outcomes included specifics of the injection protocols, including types of medication, doses, distance from limbus, use of antibiotics, and quadrants where injections were delivered.

RESULTS

A total of 1677 eyes of 918 patients (43% female, 57% male) were included. Mean gestational age was 25.7 weeks (range, 21.2-41.5 weeks), and mean birth weight was 787 g (range, 300-2700 g). Overall, a 30-gauge needle was most commonly used (51%), and the quadrant injected was most frequently the inferior-temporal (51.3%). The distance from the limbus ranged from 0.75 to 2 mm, with 1 mm being the most common (65%). Bevacizumab was the most common anti-VEGF (71.4%), with a dose of 0.625 mg in 64% of cases. Overall, 604 (36%) eyes required retreatment. Of those, 79.8% were retreated with laser alone, 10.6% with anti-VEGF injection alone, and 9.6% with combined laser and injection. Complications after anti-VEGF injections occurred in 15 (0.9%) eyes, and no cases of endophthalmitis were reported. Patients in the United States had lower birth weights and gestational ages (665.6 g and 24.5 weeks, respectively) compared with non-US patients (912.7 g and 26.9 weeks, respectively) (P < 0.0001). Retreatment with reinjection and laser was significantly more common in the US compared with the non-US group (8.5% vs. 4.7% [P = 0.0016] and 55% vs. 7.2% [P < 0.001], respectively). There was no difference in the incidence of complications between the 2 geographic subgroups.

CONCLUSIONS

Anti-VEGF injections for ROP were safe and well tolerated despite a variance in practice patterns. Infants with ROP receiving injections in the US tended to be younger and smaller, and they were treated earlier with more retreatments than non-US neonates with ROP.

Implantation Site of a Port Delivery System With Ranibizumab: Anterior Segment Optical Coherence Tomography Evaluation

Purpose: To determine whether anterior segment optical coherence tomography (AS-OCT) can be used to obtain noninvasive high-resolution images for monitoring the implantation site of a port delivery system with ranibizumab (PDS). Methods: Six eyes from the Archway phase 3 trial were imaged with AS-OCT after surgical implantation of the PDS and at regular follow-up visits. Results: AS-OCT was helpful in monitoring the status of the overlying conjunctiva and Tenon capsule after implantation of the PDS. Minimal qualitative thinning was observed over the implants at the longest follow-up. No cases of conjunctival erosion were noted. Conclusions: AS-OCT can be used to help to monitor PDS implants and potential associated complications.

Impact of age, sex and refractive error on conjunctival and Tenon's capsule thickness dimensions by swept-source optical coherence tomography in a large population

PURPOSE

To evaluate conjunctival and Tenon's capsule thickness (CTT) in a large healthy population using swept-source optical coherence tomography (SS-OCT), investigating the impact of age, sex and refractive error.

METHODS

630 healthy participants underwent a complete ophthalmological examination. CTT was manually measured in the temporal and nasal quadrants at 0, 1, 2 and 3 mm from the scleral spur using SS-OCT (CTT0, CTT1, CTT2 and CTT3, respectively). These dimensions were then assessed for associations in a multivariate regression model with age, sex, refractive error and anterior scleral thickness (AST). The reproducibility of the CTT measurements was determined in 30 individuals.

RESULTS

CTT dimensions could be measured in 596 cases (94.6%); mean age was 42.6 ± 17.2 years (range 5-86). Mean CTT0 was 199.2 ± 33.8 and 192.9 ± 33.9 µm, mean CTT1 195.4 ± 38.0 µm and 199.9 ± 50.9 µm, mean CTT2 187.0 ± 38.4 and 194.8 ± 48.9 µm, and CTT3 180.5 ± 35.6 µm and 191.8 ± 43.7 µm, for the temporal and nasal quadrants, respectively. No difference in CTT was observed in the nasal versus temporal quadrant (p ≥ 0.106) except for the CTT0 and CTT3 (p = 0.001). Moderate correlation was observed between nasal and temporal CTT (R = 0.472, p < 0.001). In the multivariate model, no influence was observed by sex, refractive error and AST on CTT measurements (p ≥ 0.065). Negative association was observed between age and CTT (p < 0.005). The reproducibility was excellent (intraclass correlation coefficient ≥ 0.908).

CONCLUSIONS

SS-OCT allows for in vivo CTT evaluation. Our data document a wide range of measurements, showing negative association between CTT and age.

Comparative study of silicone membrane simulator and animal eye models for sub-Tenon's block

To compare and assess silicone membrane-based sub-Tenon's block (STB) simulator and animal eye model (goat's eye) for practicing STB in terms of anatomical similarity and feel of texture of eye layers. The study included 34 participants (26 learners and 8 consultants) from tertiary ophthalmic centres. The participants were divided into groups A and B. Group A performed STB on the goat's eyes before using the silicone membrane simulator. Group B performed STB on the simulator and further proceeded to the goat's eye. Participants had to rate the anatomical similarity and feel of the texture for the simulator model on a scale of 0-10 and share their preference between the two models. In group A, the scores given to the simulator model and the feel of texture of layers were 8.05 ± 0.88 and 7.97 ± 1.07, respectively, and the scores given to the animal model and the feel of texture of layers were 8.11 ± 0.97 and 8.21 ± 0.88, respectively. Group B participants scored the simulator model and feel of texture of layers with 8.13 ± 0.95 and 8.25 ± 0.99, respectively. Overall, 89% participants preferred the simulator; the reasons included ease of usage, helpful warning system, absence of biological waste, and facility for repeatable training. The study validated anatomical accuracy, preference, and ability of usage of the STB simulator. For broader usage, further study involving higher number of participants is recommended.

Modifications to Combined Trabeculectomy and Manual Small Incision Cataract Surgery: Outcomes and Adaptability in Resource-constrained Areas

PRECIS

We describe standardization and simplification of classic trabeculectomy combined with manual small incision cataract surgery (MSICS) to effectively manage the 2 leading and often coexisting causes of blindness and vision impairment in resource-constrained areas.

PURPOSE

The purpose of this study was to describe modifications to trabeculectomy combined with MSICS and report on the outcomes of this technique. The modifications consist of standardization and simplification of the surgical steps.

METHODS

Data obtained from adult patients who underwent described surgical technique at rural eye care centers across 3 Indian states between January 2018 and May 2019 were analyzed retrospectively. Complete success was intraocular pressure between 6 and 18 mm Hg without supplementary medication. Qualified success allowed up to 3 topical medication(s). Data are presented as median (first and third quartiles).

RESULTS

We analyzed data of 70 eyes of 70 patients. Ophthalmology fellows performed 27 (38.5%) surgeries, whereas an experienced glaucoma specialist performed 43 (61.4%) surgeries. Patients were 63 (56, 67) years old. The preoperative intraocular pressure was 20 (16, 26) mm Hg on treatment with 3 (2, 3) antiglaucoma medications. Glaucoma was advanced by optic disc structural criteria in 58 (82.8%) eyes. Intraoperative mitomycin C was used in 5 (7.1%) eyes. Follow-up was 12.5 (6, 18) months. At 1 year, complete success (95% confidence interval) achieved was 55% (41-67), whereas qualified success was 83% (68-92) with 0 (0, 1) topical medications. The complete and qualified success rates did not differ between ophthalmology fellows and the glaucoma specialist (P=0.75 and 0.44, respectively).

CONCLUSIONS

We present a straightforward, yet effective technique of combined cataract and glaucoma surgery. The technique has a potential for wider applicability, especially in the underserved regions of the world.

The effects of laser displacement on femtosecond laser-assisted conjunctival autograft preparation for pterygium surgery

AIMS

To evaluate the effects of no-suction femtosecond laser (FSL) stability on conjunctival autograft (CAG) dissection in pterygium surgery.

METHODS

Prospective analysis of 35 eyes from 34 subjects who underwent femtosecond laser-assisted pterygium surgery with the Ziemer Z8 laser (Ophthalmic Systems AG, Switzerland). Intraoperative absolute FSL displacements were measured and correlated with the duration and ease of CAG peel, CAG thickness, measured with intraoperative optical coherence tomography, and deviation from intended graft thickness.

RESULTS

The median absolute FSL displacement was 22 μm (interquartile range [IQR] 14.7 to 60.8), while median vertical FSL displacement was 14.7 μm (IQR 7.3 to 44) and median horizontal FSL displacement was 22.0 μm (IQR 14.7 to 44). 65.7% had a grade 1 peel, 11.4% had grade 2 peel, 14.3% had grade 3 peel and 8.6% had grade 4 peel. The median duration of CAG peel was 5.4 seconds (IQR 3 to 21.4). The median CAG thickness was 69 μm (IQR 60.3 to 78.5), and the median deviation from targeted graft thickness was 9 μm (IQR 1 to 16). Eyes with more difficult peels and longer duration of CAG peels had significantly greater vertical FSL displacements (p = 0.04 and 0.02 respectively), but not horizontal displacement, age, ethnicity, CAG thickness or deviation from original thickness, compared to those with better quality and shorter duration peels. 1 eye (2.9%) had an incomplete CAG peel with a buttonhole and 2 eyes had graft tears (5.7%).

CONCLUSION

Micro-displacements during the suction-free CAG preparation are common but they did not affect the quality of the CAG peel, duration of peel, or CAG thickness. However, vertical globe displacement during FSL-assisted CAG creation was significantly associated with a more difficult and longer CAG peel duration. This highlights the importance of the cornea traction suture fixation to ensure stability of the eye during FSL application.

Effect of the outer stent position on efficacy after minimally invasive transscleral glaucoma gel stent implantation

Purpose

The outer stent lumen can be located either deeper (in or under Tenon's layer) or more superficially in the conjunctival stroma after the transscleral XEN Glaucoma Gel Microstent (XEN‐GGM; Allergan Plc., USA) implantation. The present study aimed to investigate the effect of the postoperative conjunctival implant position on surgical success and intraocular pressure (IOP) after XEN‐GGM.

Methods

Prospective data from 66 consecutive open‐angle glaucoma eyes of 54 patients were collected preoperatively and 1 and 2 weeks, and 1, 6 and 12 months postoperatively. The layer of implantation was determined in the first month postoperatively as intra‐ and subtenon or intraconjunctival depending on the location of the outer lumen of the stent in OCT (Visante OCT; Zeiss, Germany). Primary outcome measures were differences in relative IOP reduction at 12 months between the two groups. Further, complete and qualified surgical success, number of secondary needlings and number of IOP‐lowering medications and absolute IOP were assessed.

Results

Relative IOP reduction was higher in intra‐ and subtenon group (n = 37/66, 56%) at week 1 (−54% versus −19%, p < 0.001), week 2 (−39% versus −21%, p = 0.02), month 1 (−42% versus −28%, p = 0.035) and month 12 (−39% versus −24%, p = 0.024). The mean absolute IOP was lower in intra‐ and subtenon group at week 1 (10.8 [95%CI, 8.8–14.1] versus 16.6 [95%CI, 14.1–19.0] mmHg, p < 0.001) and months 12 (13.9 [95%CI, 12.4–15.4] versus 16.7 [95%CI, 14.6–18.8] mmHg, p = 0.041). At month 6, a lower burden for IOP‐lowering medication was shown for the intra‐ and subtenon group (0.2 ± 0.5 versus 1.0 ± 1.1, p = 0.034). The mean number of secondary needlings, which were done in 47/66 (71%) of the eyes, was lower in the intra‐ and subtenon group in the first year (1.9 ± 1.7 versus 1.2 ± 1.2, p = 0.03). Qualified surgical success was higher in the intra‐ and subtenon group (90% versus 61%, p = 0.01) after 1 year.

Conclusion

The present study demonstrates a higher efficacy achieved with lower secondary needling rates in deeper implant positions in conjunctiva after XEN‐GGM.

Histopathologic and immunohistochemical features of capsular tissue around failed Ahmed glaucoma valves

Impervious encapsulation around Ahmed glaucoma valve (AGV) results in surgical failure raising intraocular pressure (IOP). Dysregulation of extracellular matrix (ECM) molecules and cellular factors might contribute to increased hydraulic resistance to aqueous drainage. Therefore, we examined these molecules in failed AGV capsular tissue. Immunostaining for ECM molecules (collagen I, collagen III, decorin, lumican, chondroitin sulfate, aggrecan and keratan sulfate) and cellular factors (αSMA and TGFβ) was performed on excised capsules from failed AGVs and control tenon’s tissue. Staining intensity of ECM molecules was assessed using Image J. Cellular factors were assessed based on positive cell counts. Histopathologically two distinct layers were visible in capsules. The inner layer (proximal to the AGV) showed significant decrease in most ECM molecules compared to outer layer. Furthermore, collagen III (p = 0.004), decorin (p = 0.02), lumican (p = 0.01) and chondroitin sulfate (p = 0.02) was significantly less in inner layer compared to tenon’s tissue. Outer layer labelling however was similar to control tenon’s for most ECM molecules. Significantly increased cellular expression of αSMA (p = 0.02) and TGFβ (p = 0.008) was detected within capsular tissue compared to controls. Our results suggest profibrotic activity indicated by increased αSMA and TGFβ expression and decreased expression of proteoglycan (decorin and lumican) and glycosaminoglycans (chondroitin sulfate). Additionally, we observed decreased collagen III which might reflect increased myofibroblast contractility when coupled with increased TGFβ and αSMA expression. Together these events lead to tissue dysfunction potentially resulting in hydraulic resistance that may affect aqueous flow through the capsular wall.

An engineered human conjunctival-like tissue to study ocular surface inflammatory diseases

The aim of this study was to develop a three-dimensional model of the human conjunctiva that can be used to perform physiology and pathophysiology experiments. Fibrin-based matrices (derived from human plasma or plasma cryoprecipitate) were used as scaffolds, and primary cells were obtained from conjunctival tissue. Conjunctival constructs were analyzed by immunofluorescent staining and scanning electron microscopy and cell proliferation was measured with alamarBlue® assay. After characterizing the constructs, four different experimental conditions were analyzed in cryoprecipitate matrices: controls, air-lifted cultures (to increase cell stratification), partially desiccated cultures (to mimic dry eye disease), and IL-13-treated cultures (to mimic allergy). Constructs were stained with hematoxylin/eosin to observe changes in morphology. High molecular weight glycoconjugates were identified by HPA staining. MUC5AC and IL-6 secretion was evaluated by ELISA. The fibrin-based matrices supported conjunctival cell growth. Epithelial cells grew on the surface of the scaffolds and underwent stratification that increased over time. These cells had microvilli, which suggests cell polarization and functionality. Fibroblasts were integrated in the scaffold and showed elongated shape. Compared to controls, air-lifted construct had increased epithelial stratification and upregulated MUC5AC secretion. Increased MUC5AC secretion also occurred in partially desiccated and IL-13-treated cultures. The inflammatory status of cells was evaluated by IL-6 levels which were increased in air-lifted and partially desiccated cultures, but not in IL-13-treated ones. In conclusion, we have developed a new three-dimensional model of human conjunctiva that can be used to study ocular surface inflammatory diseases.

Anterior eye tissue morphology: Scleral and conjunctival thickness in children and young adults

The sclera and conjunctiva form part of the eye's tough, protective outer coat, and play important roles in the eye's mechanical protection and immune defence, as well as in determining the size and shape of the eye globe. Advances in ocular imaging technology now allow these tissues in the anterior eye to be imaged non-invasively and with high resolution, however there is a paucity of data examining the dimensions of these tissues in paediatric populations. In this study, we have used optical coherence tomography (OCT) imaging to examine the normal in vivo thickness profile of the anterior sclera and overlying conjunctiva in 111 healthy young participants, including a large proportion of paediatric subjects. We demonstrate that the thickness of the anterior sclera varies significantly with measurement location and meridian. Tissue thickness also varied significantly with age, with younger subjects exhibiting significantly thinner scleras and significantly greater conjunctival thickness. Males were also found to exhibit significantly greater scleral thickness. Refractive error however was not significantly associated with either scleral or conjunctival thickness in this population. These findings provide new data describing the normative dimensions of anterior eye tissues in children and the factors that can influence these dimensions in young populations.