Distinct iris gene expression profiles of primary angle closure glaucoma and primary open angle glaucoma and their interaction with ocular biometric parameters

Background

This study aimed to evaluate differences in iris gene expression profiles between primary angle closure glaucoma (PACG) and primary open angle glaucoma (POAG) and their interaction with biometric characteristics.

Design

Prospective study.

Participants

Thirty‐five subjects with PACG and thirty‐three subjects with POAG who required trabeculectomy were enrolled at the Singapore National Eye Centre, Singapore.

Methods

Iris specimens, obtained by iridectomy, were analysed by real‐time polymerase chain reaction for expression of type I collagen, vascular endothelial growth factor (VEGF)‐A, ‐B and ‐C, as well as VEGF receptors (VEGFRs) 1 and 2. Anterior segment optical coherence tomography (ASOCT) imaging for biometric parameters, including anterior chamber depth (ACD), anterior chamber volume (ACV) and lens vault (LV), was also performed pre‐operatively.

Main Outcome Measures

Relative mRNA levels between PACG and POAG irises, biometric measurements, discriminant analyses using genes and biometric parameters.

Results

COL1A1, VEGFB, VEGFC and VEGFR2 mRNA expression was higher in PACG compared to POAG irises. LV, ACD and ACV were significantly different between the two subgroups. Discriminant analyses based on gene expression, biometric parameters or a combination of both gene expression and biometrics (LV and ACV), correctly classified 94.1%, 85.3% and 94.1% of the original PACG and POAG cases, respectively. The discriminant function combining genes and biometrics demonstrated the highest accuracy in cross‐validated classification of the two glaucoma subtypes.

Conclusions

Distinct iris gene expression supports the pathophysiological differences that exist between PACG and POAG. Biometric parameters can combine with iris gene expression to more accurately define PACG from POAG.

Comparison of clinical and pathological characteristics between screen-detected and self-detected breast cancers: a Hong Kong study

INTRODUCTION

Breast cancer is the leading cause of death of Hong Kong women with increasing incidence. This study aimed to determine any prognostic differences between screen-detected and self-detected cases of breast cancer in a cohort of Hong Kong patients.

METHODS

This was a case series with internal comparison carried out in a private hospital in Hong Kong. Approximately 3000 cases of Chinese patients diagnosed with ductal carcinoma in situ or invasive breast cancer were reviewed.

RESULTS

The screen-detected group showed better pathological characteristics than the self-detected group. Number of lymph nodes involved, invasive tumour size, and tumour grade were more favourable in the screen-detected group. There was also a lower proportion of patients with pure invasive ductal carcinoma and mastectomy in the screen-detected group.

CONCLUSION

This study provides indirect evidence that women in the local population may gain clinical benefit from regular breast cancer screening. The findings need to be validated in a representative population of Hong Kong women.

Argon Laser Peripheral Iridoplasty for Primary Angle-Closure Glaucoma: A Randomized Controlled Trial

PURPOSE

To determine the effectiveness of argon laser peripheral iridoplasty (ALPI) in primary angle closure (PAC) and primary angle-closure glaucoma (PACG).

DESIGN

Randomized controlled trial.

PARTICIPANTS

Eighty PAC or PACG subjects who underwent laser iridotomy (LI) and had at least 180° of persistent appositional angle closure and intraocular pressure (IOP) of more than 21 mmHg were enrolled.

METHODS

Subjects were randomized to receive either 360° ALPI (Visulas 532s; Carl Zeiss Meditec, Jena, Germany) or medical therapy (Travoprost 0.004%; Alcon-Couvreur, Puurs, Antwerp, Belgium). Repeat ALPI was performed if the IOP reduction was less than 20% from baseline along with inadequate angle widening at the month 1 or month 3 visit. Intraocular pressure was controlled with systematic addition of medications when required.

MAIN OUTCOME MEASURES

The primary outcome measure was success rates after ALPI at 1 year. Complete success was defined as an IOP of 21 mmHg or less without medication, and qualified success was defined as an IOP of 21 mmHg or less with medication. Failure was defined as an IOP more than 21 mmHg despite additional medications or requiring glaucoma surgery.

RESULTS

Forty subjects (51 eyes) were randomized to ALPI and 40 subjects (55 eyes) were randomized to medical therapy. Complete success (IOP ≤21 mmHg without medication) was achieved in 35.0% eyes of the ALPI group compared with 85.0% of eyes in the prostaglandin analog (PGA) group (P < 0.001), and qualified success (IOP ≤21 mmHg with medication) was achieved in 35.0% and 7.5%, respectively (P = 0.003). The IOP decreased by 4.9 mmHg (95% confidence interval [CI], 3.5-6.3 mmHg) in the ALPI group (P < 0.001) and by 6.1 mmHg (95% CI, 5.1-7.1 mmHg) in the medication group (P < 0.001). A failure rate of 30.0% was noted in the ALPI group compared with 7.5% in the medication group (P = 0.01). No treatment-related complications were recorded in either group.

CONCLUSIONS

After 1 year, ALPI was associated with higher failure rates and lower IOP reduction compared with PGA therapy in eyes with persistent appositional angle closure and raised IOP after LI.

Valproic acid suppresses collagen by selective regulation of Smads in conjunctival fibrosis

Overproduction of type I collagen is associated with a wide range of fibrotic diseases as well as surgical failure such as in glaucoma filtration surgery (GFS). Its modulation is therefore of clinical importance. Valproic acid (VPA) is known to reduce collagen in a variety of tissues with unclear mechanism of action. In this report, we demonstrate that VPA inhibited collagen production in both conjunctival fibroblasts and the mouse model of GFS. In fibroblasts, VPA decreased type I collagen expression which intensified with longer drug exposure and suppressed steady-state type I collagen promoter activity. Moreover, VPA decreased Smad2, Smad3 and Smad4 but increased Smad6 expression with a similar intensity-exposure profile. Reduction of Smad3 using small hairpin RNA and/or overexpression of Smad6 resulted in decreased collagen expression which was exacerbated when VPA was simultaneously present. Furthermore, fibrogenic TGF-β2 failed to induce collagen when VPA was present, as opposed to the myofibroblast markers, beta-actin, alpha-smooth muscle actin and tenascin-C, which were elevated by TGF-β2. VPA suppressed p3TP-Lux luciferase activity and selectively rescued Smad6 expression from suppression by TGF-β2. Notably, SMAD6 overexpression reduced the effectiveness of TGF-β2 in inducing collagen expression. In corroboration, VPA inhibited type I collagen but increased Smad6 expression in the late phase of wound healing in the mouse model of GFS. Taken together, our data indicate that VPA has the capacity to effectively suppress both steady-state and fibrogenic activation of type I collagen expression by modulating Smad expression. Hence, VPA is potentially applicable as an anti-fibrotic therapeutic by targeting collagen. Key message: • VPA modulates type I collagen expression via members of the Smad family. • VPA suppresses Smad2, Smad3 and Smad4 but upregulates Smad6. • Smad3 and Smad6 are involved in VPA regulation of steady-state collagen expression. • Smad6 is involved in VPA modulation of TGF-β-stimulated collagen expression. • VPA reduces collagen and upregulates Smad6 in the mouse model of glaucoma filtration surgery.

Graft failure and intraocular pressure control after keratoplasty in iridocorneal endothelial syndrome

PURPOSE

To describe and compare graft survival and intraocular pressure (IOP) control after penetrating keratoplasty (PK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with iridocorneal endothelial (ICE) syndrome.

DESIGN

Retrospective case series.

METHODS

Multicenter study conducted at the Singapore National Eye Centre (SNEC) and Price Vision Group. Twenty-nine consecutive eyes with ICE syndrome that underwent keratoplasty between 1991 and 2011 were identified from the SNEC transplant database and Price Vision Group patient database and the following data extracted: demographics, graft failure, IOP indices, and glaucoma treatment pre- and postkeratoplasty. The main outcome measures were graft failure and need for additional IOP-lowering treatment after keratoplasty.

RESULTS

The mean follow-up duration was 7.0 ± 4.9 years in the PK group (n = 17) and 4.0 ± 2.6 years in the DSAEK group (n = 12). After a mean of 4.1 ± 3.1 years, 37.9% of grafts (11/29) failed: 7 PK compared to 4 DSAEK (P = .72). The graft failure rate was 50% in eyes with prekeratoplasty glaucoma surgery vs 31.6% in those without (P = .43). Additional glaucoma treatment was required in 37.9% of eyes (11/29): 41.2% of PK eyes and 50% of DSAEK eyes (P = .28) Eyes that had undergone glaucoma surgery before keratoplasty were less likely to require escalation of IOP-lowering therapy postkeratoplasty (9.1% vs 50%, P = .03).

CONCLUSIONS

One-third of grafts failed after keratoplasty for ICE syndrome at a mean duration of 4 years and additional IOP-lowering treatment was required in 37.9%. Both PK and DSAEK had similar outcomes with regard to graft failure and IOP control.

Bleb needling outcomes for failed trabeculectomy blebs in Asian eyes: a 2-year follow up

AIM

To describe the outcomes of bleb needling in primary glaucoma in an Asian tertiary eye centre over a 2y period. To compare the success rates between primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG). Lastly, to identify factors associated with success of bleb needling.

METHODS

This was a retrospective review of 227 patients who underwent bleb needling between June 2009 and June 2011 in Singapore National Eye Centre. The 5-fluorouracil (5-FU) augmented bleb needling was performed either at the slit lamp or in the operating theatre. Repeat bleb needlings were performed as necessary. Complete success was defined as maintenance of intraocular pressure (IOP) ≥6 mm Hg and ≤21 mm Hg, in the absence of further surgery or use of antiglaucoma medication. Qualified success met the above criteria with or without use of antiglaucoma medications.

RESULTS

One hundred and seventy-five eyes completed the two-year follow up. Sixty-nine percent of participants had POAG and 31% had PACG. The mean interval between filtering surgery and bleb needling was 299.9±616.4d for POAG and 167.1±272.2d for PACG. Mean needling attempts were 1.9±1.4 and 2±1.6 for POAG and PACG respectively. In general, there was a statistically significant reduction of IOP ranging from 21.9% to 26.8% from month 1 through to month 24. The complete success rates at month 6 were 70.0% for POAG and 65.7% for PACG. At month 12, this decreased to 62.2% for POAG and PACG and at month 24, 57.9% for POAG and 63.0% for PACG respectively. The qualified success rates at month 6 for POAG and PACG were 23.8% and 29.9% respectively, 32.2% and 29.2% at month 12, and 34.7% and 29.6% at month 24. The success rates between POAG and PACG were not significantly different (P>0.05 for complete and qualified success at months 6, 12 and 24). An increased number of needlings and higher pre-needling IOP were associated with failure.

CONCLUSION

The 5-FU augmented bleb needling within one year of trabeculectomy in Asian eyes can provide clinically significant IOP lowering of more than 20% for 2y. POAG and PACG had similar complete success rates (58% and 63% respectively). Factors associated with greater risk of procedure failure included increased number of needlings and higher pre-needling IOP. Asian eyes have a greater propensity for scarring but bleb needling, if performed in a timely manner can rescue bleb function.

A common variant near TGFBR3 is associated with primary open angle glaucoma

Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10⁻³³), we observed one SNP showing significant association to POAG (CDC7–TGFBR3 rs1192415, OR_G-allele = 1.13, P_meta = 1.60 × 10⁻⁸). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis.

Efficacy of selective laser trabeculoplasty in primary angle-closure glaucoma: a randomized clinical trial

IMPORTANCE

Selective laser trabeculoplasty (SLT) should be explored as a therapeutic option in eyes with angle closure.

OBJECTIVE

To assess the intraocular pressure (IOP)-lowering efficacy of SLT in eyes with primary angle closure (PAC) and PAC glaucoma (PACG).

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial at tertiary eye care institutions of 100 patients diagnosed as having PAC or PAC glaucoma in which the angles had opened at least 180° (visible posterior trabecular meshwork on gonioscopy) after laser iridotomy. Recruitment and baseline were completed from June 2009 to April 2012 and 6-month follow-up was completed from December 2009 to November 2012.

INTERVENTIONS

Eligible patients with a baseline IOP greater than 21 mm Hg were randomized to either SLT or prostaglandin analog (PGA; travoprost, 0.004%). The SLT was repeated if the IOP reduction was less than 20.0% from baseline at the 1- or 3-month follow-up visit.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was the change in IOP from baseline to the final follow-up visit (at 6 months). The frequency of additional postoperative treatments and complications were secondary outcomes.

RESULTS

Fifty patients (96 eyes) were randomized to SLT and 50 patients (99 eyes) to PGA medical therapy. At 6 months, 49 patients in the SLT group and 47 in the PGA group completed follow-up. Analysis was based on intent to treat. At 6 months, IOP decreased by 4.0 mm Hg (95% CI, 3.2-4.8) in the SLT group (P < .001) and by 4.2 mm Hg (95% CI, 3.5-4.9) in the PGA group (P < .001). There were no differences between the SLT and PGA groups in the absolute mean reduction of IOP (4.0 vs 4.2 mm Hg, respectively; P = .78) or in the percentage of reduction in IOP (16.9% vs 18.5%, respectively; P = .52). Complete success (IOP ≤21 mm Hg without medications) was achieved in 60.0% eyes of the SLT group, compared with 84.0% of eyes in the PGA group (P = .008). No patients required glaucoma surgery. Additional medications were required in 22.0% of patients in the SLT group compared with 8.0% in the PGA group (P = .05). One patient in the SLT group (2.0%) had a transient posttreatment IOP spike greater than 5 mm Hg. The mean endothelial cell count showed a significant decrease from baseline in the SLT arm (4.8% decrease; P = .001). No other events such as persistent uveitis or increase in peripheral anterior synechiae were noted in eyes that underwent SLT. Two patients in the PGA group exited owing to drug-related complications (1 patient with uveitis and 1 with allergic conjunctivitis).

CONCLUSIONS AND RELEVANCE

Eyes with PAC or PACG respond to SLT in the short term, but the overall long-term therapeutic effectiveness needs further evaluation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01004900.

Ocular surface disease in posttrabeculectomy/mitomycin C patients

Background

Our aim was to describe the demographics, risk factors, clinical signs, severity, and outcome of ocular surface disease (OSD) in 12 patients who had undergone trabeculectomy augmented with mitomycin C (MMC).

Methods

Twelve glaucoma patients were referred to the Dry Eye Clinic (Singapore National Eye Centre) for further management of clinically significant OSD.

Results

Of the 15 eyes from 12 patients, 14 were treated with MMC and one with 5-fluorouracil. Mean age was 69.3±10.6 years and two-thirds were male. The median interval before onset of dry eye symptoms after surgery was 13.5 months. Mean tear breakup time (TBUT) was 5.32 seconds and mean Schirmer score was 6.14 mm/5 min. Possible major risk factors for OSD in the cases include limbal stem cell deficiency occurring from exposure to antimetabolites, chronic use of antiglaucoma medications prior to surgery, and the preoperative status of the ocular surface prior to disease onset. Treatment of OSD resulted in improved best corrected visual acuity (BCVA) in 50% of the patients, with a median gain of two-line improvement in BCVA.

Conclusion

OSD is a clinical problem often overlooked in patients who undergo antimetabolite-augmented filtration surgery. Recognition of the condition and appropriate treatment can improve patient symptoms and reduce health-care burdens on the economy.

Layer-by-layer nanoparticles as an efficient siRNA delivery vehicle for SPARC silencing

Efficient and safe delivery systems for siRNA therapeutics remain a challenge. Elevated secreted protein, acidic, and rich in cysteine (SPARC) protein expression is associated with tissue scarring and fibrosis. Here we investigate the feasibility of encapsulating SPARC-siRNA in the bilayers of layer-by-layer (LbL) nanoparticles (NPs) with poly(L-arginine) (ARG) and dextran (DXS) as polyelectrolytes. Cellular binding and uptake of LbL NPs as well as siRNA delivery were studied in FibroGRO cells. siGLO-siRNA and SPARC-siRNA were efficiently coated onto hydroxyapatite nanoparticles. The multilayered NPs were characterized with regard to particle size, zeta potential and surface morphology using dynamic light scattering and transmission electron microscopy. The SPARC-gene silencing and mRNA levels were analyzed using ChemiDOC western blot technique and RT-PCR. The multilayer SPARC-siRNA incorporated nanoparticles are about 200 nm in diameter and are efficiently internalized into FibroGRO cells. Their intracellular fate was also followed by tagging with suitable reporter siRNA as well as with lysotracker dye; confocal microscopy clearly indicates endosomal escape of the particles. Significant (60%) SPARC-gene knock down was achieved by using 0.4 pmole siRNA/μg of LbL NPs in FibroGRO cells and the relative expression of SPARC mRNA reduced significantly (60%) against untreated cells. The cytotoxicity as evaluated by xCelligence real-time cell proliferation and MTT cell assay, indicated that the SPARC-siRNA-loaded LbL NPs are non-toxic. In conclusion, the LbL NP system described provides a promising, safe and efficient delivery platform as a non-viral vector for siRNA delivery that uses biopolymers to enhance the gene knock down efficiency for the development of siRNA therapeutics.

A new design and application of bioelastomers for better control of intraocular pressure in a glaucoma drainage device

Glaucoma drainage device (GDD) implantation is an effective method of lowering the intraocular pressure (IOP). Commonly used GDDs can be classified into nonvalved and valved. Although a stable IOP is critical, currently available devices often cause extreme IOP fluctuations: nonvalved GDDs suffer from a risk of hypotony (IOP<5 mmHg), whereas valved GDDs have a higher risk ocular hypertensive (IOP>22 mmHg). It is hypothesized that a GDD with a valve designed to open around the time of onset of the hypertensive phase, would minimize IOP fluctuation. Accordingly, a valve fabricated from a biodegradable polymer poly(L-lactide-co-ϵ-caprolactone) (PLC 70/30) is evaluated in vitro and in vivo. The pressure response is compared with its non-degradable counterpart in in vitro studies of IOP. It is also established that in vitro, the biodegradability of the valve is programmed to occur over 12 weeks. In vivo, a steady and low IOP is achieved with the biodegradable valve and the hypertensive phase is significantly attenuated compared with the commercial device. Fibrotic encapsulation of the device is also minimized with the biodegradable valve in vivo.

Sustained drug release in nanomedicine: a long-acting nanocarrier-based formulation for glaucoma

Therapeutic nanomedicine has concentrated mostly on anticancer therapy by making use of the nanosize for targeted therapy. Such nanocarriers are not expected to have sustained release of the bioactive molecule beyond a few days. There are other conditions where patients can benefit from sustained duration of action following a single instillation, but achieving this has been difficult in nanosized carriers. An important prerequisite for sustained delivery over several months is to have sufficiently high drug loading, without disruption or changes to the shape of the nanocarriers. Here we report on successful development of a drug-encapsulated nanocarrier for reducing intraocular pressure in a diseased nonhuman primate model and explain why it has been possible to achieve sustained action in vivo. The drug is a prostaglandin derivative, latanoprost, while the carrier is a nanosized unilamellar vesicle. The mechanistic details of this unique drug-nanocarrier combination were elucidated by isothermal titration calorimetry. We show, using Cryo-TEM and dynamic light scattering, that the spherical shape of the liposomes is conserved even at the highest loading of latanoprost and that specific molecular interactions between the drug and the lipid are the reasons behind improved stability and sustained release. The in vivo results clearly attest to sustained efficacy of lowering the intraocular pressure for 120 days, making this an excellent candidate to be the first truly sustained-release nanomedicine product. The mechanistic details we have uncovered should enable development of similar systems for other conditions where sustained release from nanocarriers is desired.

Efficacy and safety of collagen matrix implants in phacotrabeculectomy and comparison with mitomycin C augmented phacotrabeculectomy at 1 year

BACKGROUND

To assess the efficacy and safety of collagen matrix implant (Ologen) in phacotrabeculectomy.

DESIGN

Prospective, non-randomized, comparative study.

PARTICIPANTS

Sixty-six Asian patients.

METHODS

Thirty three consecutive patients underwent phacotrabeculectomy with Ologen implant and intraocular lens implantation, and 33 subjects recruited as controls underwent surgery with mitomycin C augmentation.

MAIN OUTCOME MEASURES

The primary outcome measure was postoperative intraocular pressure at month 12. Additional postoperative treatments, such as bleb needling, and adverse events were secondary outcomes.

RESULTS

The overall percentage reduction in intraocular pressure was 13% (95% confidence interval 6.7-19.2) in the Ologen group and 26% (95% confidence interval 14.8-37.9) in the mitomycin C group (P = 0.05). At 1 year after surgery (after adjusting for baseline differences), intraocular pressure decreased by 4.2 mmHg (95% confidence interval 2.8-5.6 mmHg) and 5.6 mmHg (95% confidence interval 4.2-7.0 mmHg), respectively (P = 0.16). Needling with 5-fluorouracil was required more often in the Ologen group (39% vs. 6%; P = 0.003). There was similar frequency (<10%) of adverse events in both groups, and there were no complications directly related to the Ologen implant. The blebs in the mitomycin C group had greater central area (P = 0.005), maximal area (P = 0.01) and height (P = 0.005), and were less vascular (P = 0.023) than the Ologen blebs.

CONCLUSIONS

At 1 year, the overall performance of Ologen in combined phacotrabeculectomy was suboptimal compared with combined surgery with mitomycin C. Eyes in the Ologen group required more frequent bleb needling procedures.

Hevin plays a pivotal role in corneal wound healing

Background

Hevin is a matricellular protein involved in tissue repair and remodeling via interaction with the surrounding extracellular matrix (ECM) proteins. In this study, we examined the functional role of hevin using a corneal stromal wound healing model achieved by an excimer laser-induced irregular phototherapeutic keratectomy (IrrPTK) in hevin-null (hevin^-/-) mice. We also investigated the effects of exogenous supplementation of recombinant human hevin (rhHevin) to rescue the stromal cellular components damaged by the excimer laser.

Methodology/Principal Findings

Wild type (WT) and hevin^-/- mice were divided into three groups at 4 time points- 1, 2, 3 and 4 weeks. Group I served as naïve without any treatment. Group II received epithelial debridement and underwent IrrPTK using excimer laser. Group III received topical application of rhHevin after IrrPTK surgery for 3 days. Eyes were analyzed for corneal haze and matrix remodeling components using slit lamp biomicroscopy, in vivo confocal microscopy, light microscopy (LM), transmission electron microscopy (TEM), immunohistochemistry (IHC) and western blotting (WB). IHC showed upregulation of hevin in IrrPTK-injured WT mice. Hevin^-/- mice developed corneal haze as early as 1-2 weeks post IrrPTK-treatment compared to the WT group, which peaked at 3-4 weeks. They also exhibited accumulation of inflammatory cells, fibrotic components of ECM proteins and vascularized corneas as seen by IHC and WB. LM and TEM showed activated keratocytes (myofibroblasts), inflammatory debris and vascular tissues in the stroma. Exogenous application of rhHevin for 3 days reinstated inflammatory index of the corneal stroma similar to WT mice.

Conclusions/Significance

Hevin is transiently expressed in the IrrPTK-injured corneas and loss of hevin predisposes them to aberrant wound healing. Hevin^-/- mice develop early corneal haze characterized by severe chronic inflammation and stromal fibrosis that can be rescued with exogenous administration of rhHevin. Thus, hevin plays a pivotal role in the corneal wound healing.

De novo ocular hypertension after Descemet stripping endothelial keratoplasty: comparative 3-year incidence, risk factors, and outcomes

OBJECTIVE

To compare the 3-year incidence of de novo ocular hypertension (OHT) after Descemet stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty (PK). For DSAEK, to evaluate predictors for OHT and 2-year outcomes after OHT development.

METHODS

This was a review of the prospective Singapore Corneal Transplant Study at a single tertiary referral center. Consecutive DSAEKs and PKs for Fuchs' endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK) in eyes without pre-existing glaucoma were analyzed. OHT incidence after DSAEK and PK were compared using Kaplan-Meier survival analysis, and OHT risk factors identified using Cox proportional regression. OHT was defined: intraocular pressure (IOP) ≥ 24 mmHg or ≥ 10 mmHg from baseline. Secondary outcomes 2 years after OHT development in DSAEK were rates of glaucoma medical therapy failure, IOP success, graft failure and rejection, and best-spectacle corrected visual acuity (BSCVA).

RESULTS

There were 108 (96.4%) DSAEKs and 216 (96%) PKs. The 1-, 2- and 3-year de novo OHT incidence was not significantly different between DSAEK (36.1%, 47.2%, 47.2%, respectively) and PK (35.7%, 44.9%, 45.8%, respectively; P = 0.914). OHT incidence did not differ in subgroup analyses of multiple clinical variables (P > 0.1). OHT predictors after DSAEK were: fellow eye glaucoma (hazard ratio [HR] 3.20, P = 0.004), age <60 years (HR 2.41, P = 0.016), concurrent goniosynechiolysis (HR 3.29, P = 0.021), post-graft complications or procedures (HR 2.85, P = 0.006). Two years after OHT onset, 29.7% of DSAEKs failed glaucoma medical therapy requiring trabeculectomy. Complete and qualified IOP success was achieved in 23.5% and 76.5%, respectively. Graft failure developed in 9.8% and graft rejection in 5.9%. At 6 months, 1, and 2 years from OHT onset, 86.3%, 88.3%, and 92.1% achieved BSCVA 20/40, respectively.

CONCLUSION

DSAEK and PK have comparable OHT risks. A significant 30% of DSAEK eyes with OHT require filtration surgery. Effective IOP control and good graft and visual outcomes are achieved with treatment.

A biodegradable, sustained-released, prednisolone acetate microfilm drug delivery system effectively prolongs corneal allograft survival in the rat keratoplasty model

Frequent and long-term use of topical corticosteroids after corneal transplantation is necessary to prevent graft rejection. However, it relies heavily on patient compliance, and sustained therapeutic drug levels are often not achieved with administration of topical eye drops. A biodegradable drug delivery system with a controlled and sustained drug release may circumvent these limitations. In this study, we investigated the efficacy of a prednisolone acetate (PA)-loaded poly (d,l-lactide-co-ε-caprolactone) (PLC) microfilm drug delivery system on promoting the survival of allogeneic grafts after penetrating keratoplasty (PK) using a rat model. The drug release profiles of the microfilms were characterized (group 1). Subsequently, forty-eight PK were performed in four experimental groups: syngeneic control grafts (group 2), allogeneic control grafts (group 3), allogeneic grafts with subconjunctivally-implanted PA microfilm (group 4), and allogeneic grafts with PA eye drops (group 5; n = 12 in each). PA-loaded microfilm achieved a sustained and steady release at a rate of 0.006-0.009 mg/day, with a consistent aqueous drug concentration of 207-209 ng/ml. The mean survival days was >28 days in group 2, 9.9±0.8 days in group 3, 26.8±2.7 days in group 4, and 26.4±3.4 days in group 5 (P = 0.023 and P = 0.027 compared with group 3). Statistically significant decrease in CD4+, CD163+, CD 25+, and CD54+ cell infiltration was observed in group 4 and group 5 compared with group 3 (P<0.001). There was no significant difference in the mean survival and immunohistochemical analysis between group 4 and group 5. These results showed that sustained PA-loaded microfilm effectively prolongs corneal allograft survival. It is as effective as conventional PA eye drops, providing a promising clinically applicable alternative for patients undergoing corneal transplantation.

Effect of chronic anti-glaucoma medications and trabeculectomy on tear osmolarity

PURPOSE

To evaluate the tear film osmolarity (TFO) and ocular surface clinical signs and symptoms in chronically medicated glaucoma patients and post-trabeculectomy patients.

METHODS

This is a single-center, prospective case-controlled study. One-hundred and thirty eyes of 130 participants aged ≥ 45 years were included (49 normal controls, 50 glaucoma patients on chronic preserved anti-glaucoma medication ≥ 6 months, and 31 post-trabeculectomy patients not on medication ≥ 6 months). TFO, tear break-up time (TBUT), Schirmer's test I and dry eye symptoms were evaluated. Data from both groups of glaucoma patients were compared with age and sex-matched controls. Logistic regression was performed to calculate the odds ratios.

RESULTS

Mean TFO in the three groups were 301.4 ± 7.7, 307.0 ± 9.3, and 307.4 ± 11.6 mOsm/l, respectively. Compared with normal controls, chronically medicated glaucoma patients and post-trabeculectomy patients were more likely to have a raised TFO, with odds ratios (95% CI) of 4.43 (1.74-11.32) and 2.76 (1.02-7.94), respectively. Both groups of glaucoma patients were also more likely to experience dry eye symptoms, with ORs of 4.72 (1.92-11.59) and 4.24 (1.54-11.72). There was no significant difference in TFO and symptoms between both groups of glaucoma patients, and in TBUT and Schirmer's test across all three groups.

CONCLUSIONS

Patients on chronic topical anti-glaucoma medication and post-trabeculectomy patients were more likely to have raised TFO and dry eye symptoms, suggesting significant ocular surface disease. Glaucoma practitioners should be aware that dry eye symptoms and raised TFO may occur in the absence of TBUT and Schirmer's test abnormality.

Optimization of subconjunctival biodegradable microfilms for sustained drug delivery to the anterior segment in a small animal model

PURPOSE

We evaluated a biodegradable, sustained-release, prednisolone acetate (PA)-loaded poly[d,l-lactide-co-ε-caprolactone] (PLC) drug delivery system on its biocompatibility, feasibility and release characteristics in vitro and in vivo.

METHODS

Blank and 40% PA-loaded PLC microfilms with a diameter of 2 mm were fabricated, and the degradation and drug release profiles of the microfilms were characterized in vitro and in vivo. The microfilms were implanted into the subconjunctival space of Lewis rats (n = 48). All eyes were assessed clinically using slit-lamp biomicroscopy, and graded with Hackett-McDonald ocular scoring system and anterior segment optical coherence tomography. Histologic and immunohistochemical analyses were performed comparing blank and PA-loaded microfilm groups. PA concentrations in the aqueous humor were determined by HPLC.

RESULTS

Subconjunctivally-implanted PLC microfilms were able to deliver PA in a sustained manner over 3 months, with a steady rate of 0.002 mg/d in vivo. Eyes with either blank or PA-loaded implanted microfilms showed a very minimal inflammatory response at the insertion sites and mild degree of collagen encapsulation around the microfilms, with significantly less CD11c cells at 2 and 4 weeks (P = 0.001 and P = 0.002), and collagen formation at 2 weeks (P = 0.001) in the PA-loaded microfilm group. Anterior chamber PA levels were achieved, with concentrations at 76.7 ± 5.9, 70.3 ± 2.3, and 42.7 ± 4.1 ng/mL at 2, 4, and 12 weeks, respectively.

CONCLUSIONS

PA-loaded PLC microfilms display good biocompatibility, feasibility, and desirable sustained drug release profiles, and have the potential to exhibit antifibrotic and anti-inflammatory effects. This device is applicable to use in small animal models of anterior segment inflammation.

Acceptance, attitudes, and beliefs of Singaporean Chinese toward an ocular implant for glaucoma drug delivery

PURPOSE

We investigated patients' attitudes and perceptions toward a subconjunctival implant as a novel ocular drug delivery method for glaucoma.

METHODS

We recruited 344 Chinese patients with primary open angle or angle closure glaucoma currently on topical antiglaucoma medication for a minimum of six months from specialist glaucoma clinics. Sociodemographic data, and information about patients' general and ocular health were collected. Beliefs about medicines, glaucoma, eye drops, and self-reported adherence were assessed by trained interviewers using validated questionnaires. A description about the implant was provided and patients subsequently were assessed on their understanding and acceptance.

RESULTS

Of the 344 Chinese patients enrolled, 216 (62.8%) would accept the implant as a replacement for their current eye drops. Of those who accepted the implant, 99 (45.8%) were willing to accept it at similar costs, while 40 (18.5%) and 20 (9.3%) patients were willing to pay 1.5 and 2 times the cost of their present medication, respectively. Patients who accepted the implant had more severe glaucoma (P = 0.015) and felt that the implant was more helpful than eye drops (P < 0.001). Beliefs toward medicines, glaucoma, eye drops, self-reported adherence, and sociodemographic factors did not have a significant impact on the patients' decisions.

CONCLUSIONS

An ocular drug implant would be an acceptable alternative to topical eye drops for subgroups of glaucoma patients.

In vitro analyses of the anti-fibrotic effect of SPARC silencing in human Tenon's fibroblasts: comparisons with mitomycin C

Failure of glaucoma filtration surgery (GFS) is commonly attributed to scarring at the surgical site. The human Tenon’s fibroblasts (HTFs) are considered the major cell type contributing to the fibrotic response. We previously showed that SPARC (secreted protein, acidic, rich in cysteine) knockout mice had improved surgical success in a murine model of GFS. To understand the mechanisms of SPARC deficiency in delaying subconjunctival fibrosis, we used the gene silencing approach to reduce SPARC expression in HTFs and examined parameters important for wound repair and fibrosis. Mitomycin C-treated HTFs were used for comparison. We demonstrate that SPARC-silenced HTFs showed normal proliferation and negligible cellular necrosis but were impaired in motility and collagen gel contraction. The expression of pro-fibrotic genes including collagen I, MMP-2, MMP-9, MMP-14, IL-8, MCP-1 and TGF-β₂ were also reduced. Importantly, TGF-β₂ failed to induce significant collagen I and fibronectin expressions in the SPARC-silenced HTFs. Together, these data demonstrate that SPARC knockdown in HTFs modulates fibroblast functions important for wound fibrosis and is therefore a promising strategy in the development of anti-scarring therapeutics.

Outcomes of trabeculectomy after descemet stripping automated endothelial keratoplasty: a comparison with penetrating keratoplasty

PURPOSE

To compare the outcomes of trabeculectomy surgery after Descemet stripping automated endothelial keratoplasty (DSAEK) to penetrating keratoplasty (PK).

DESIGN

Retrospective case-control study.

METHODS

Patients within an institutional setting who underwent trabeculectomy with mitomycin C (MMC) for uncontrolled elevated intraocular pressure (IOP) after corneal graft surgery were included. Patients with pre-existing glaucoma were excluded. Twenty patients with trabeculectomy after DSAEK and 41 patients with trabeculectomy after PK were analyzed. The main outcome measure was IOP control at 12 months. Secondary outcome measures were postoperative interventions including reinstatement of IOP-lowering medications, bleb needling with 5-fluorouracil (5FU) or further glaucoma surgery, and the incidence of complications related to trabeculectomy and/or corneal graft surgery.

RESULTS

There was no difference in pre-trabeculectomy IOP between DSAEK vs PK group (35.5 ± 10.1 vs 32.9 ± 8.9, P = .31). At 12 months after trabeculectomy, mean IOP in the DSAEK group was lower compared to the PK controls (10.6 ± 3.2 vs 14.6 ± 8.5, P = .04). The proportion of patients who achieved an IOP less than 12 mm Hg was significantly higher in the DSAEK group (80.0% vs 48.6%, P = .03). The proportions of eyes that required intervention after trabeculectomy were comparable between the 2 groups (DSAEK vs PK, all interventions: 20.0% vs 39.5%, P = .15; IOP-lowering medications required: 15.0% vs 39.5%, P = .08; needling with 5FU: 20.0% vs 23.7%, P > .99; further glaucoma surgery: 0% vs 13.2%, P = .15). Corneal graft failure arising after trabeculectomy was seen in 10.0% of DSAEK cases and in 10.5% of PK controls (P = 1.0).

CONCLUSION

Compared to trabeculectomy after PK, trabeculectomy after DSAEK achieved lower mean IOP at 12 months, and a larger proportion of DSAEK patients achieved an IOP of less than 12 mm Hg. There was no difference in the need for intervention after trabeculectomy, or incidence of other complications. Trabeculectomy is an effective surgical procedure for the management of postgraft ocular hypertension in DSAEK patients, and DSAEK may have an advantage in terms of success of trabeculectomy surgery over PK.