Topical and oral peroxisome proliferator-activated receptor-α agonist ameliorates diabetic corneal neuropathy.

Diabetic corneal neuropathy (DCN) is a common diabetic ocular complication with limited treatment options. In this study, we investigated the effects of topical and oral fenofibrate, a peroxisome proliferator-activated receptor-α agonist, on the amelioration of DCN using diabetic mice (n = 120). Ocular surface assessments, corneal nerve and cell imaging analysis, tear proteomics and its associated biological pathways, immuno-histochemistry and western blot on PPARα expression, were studied before and 12 weeks after treatment. At 12 weeks, PPARα expression markedly restored after topical and oral fenofibrate. Topical fenofibrate significantly improved corneal nerve fibre density (CNFD) and tortuosity coefficient. Likewise, oral fenofibrate significantly improved CNFD. Both topical and oral forms significantly improved corneal sensitivity. Additionally, topical and oral fenofibrate significantly alleviated diabetic keratopathy, with fenofibrate eye drops demonstrating earlier therapeutic effects. Both topical and oral fenofibrate significantly increased corneal ß-III tubulin expression. Topical fenofibrate reduced neuroinflammation by significantly increasing the levels of nerve growth factor and substance P. It also significantly increased ß-III-tubulin and reduced CDC42 mRNA expression in trigeminal ganglions. Proteomic analysis showed that neurotrophin signalling and anti-inflammation reactions were significantly up-regulated after fenofibrate treatment, whether applied topically or orally. This study concluded that both topical and oral fenofibrate ameliorate DCN, while topical fenofibrate significantly reduces neuroinflammation.

Effects of Different Capsulotomy and Fragmentation Energy Levels on the Generation of Oxidative Stress Following Femtosecond Laser-Assisted Cataract Surgery.

PURPOSE: This study was conducted to evaluate the effects of different capsulotomy and fragmentation energy levels on the production of oxidative free radicals following femtosecond laser-assisted cataract surgery (FLACS) with a low-energy platform. METHODS: The experimental study included 60 porcine eyes (12 groups). In each group, capsulotomies with 90% or 150% energy, and fragmentations with 90%, 100%, or 150% energy or 150% with high spot density, respectively, were performed. Control samples were obtained from non-lasered eyes at the beginning (five eyes) and end (five eyes) of the experiment. In the clinical study, 104 eyes were divided into 5 groups, and they received conventional phacoemulsification (20 eyes), FLACS with 90% capsulotomy and 100% fragmentation energy levels without NSAIDs (16 eyes), FLACS with 90% (26 eyes) or 150% (22 eyes) capsulotomy energy levels, respectively, with a 100% fragmentation energy level and NSAIDs, and FLACS with 90% capsulotomy and 150% fragmentation energy levels and NSAIDs (20 eyes). Aqueous samples were analyzed for their malondialdehyde (MDA) and superoxide dismutase (SOD) levels. RESULTS: In the experimental study, there were no significant differences in the MDA and SOD levels between the groups with different capsulotomy energy levels. An increase in the fragmentation energy from 100% to 150% led to significantly higher MDA levels in the groups with both 90% (p = 0.04) and 150% capsulotomy energy levels (p = 0.03), respectively. However, increased laser spot densities did not result in significant changes in MDA or SOD levels. In the clinical study, all four of the FLACS groups showed higher MDA levels than the conventional group. Similarly, the increase in the fragmentation energy from 100% to 150% resulted in significantly elevated levels of MDA and SOD, respectively. CONCLUSIONS: Although increasing the FSL capsulotomy energy level may not have increased free radicals, higher fragmentation energy levels increased the generation of aqueous free radicals. However, fragmentation with high spot density did not generate additional oxidative stress. Increased spot density did not generate additional oxidative stress, and this can be helpful for dense cataracts.

Femtosecond laser-assisted posterior capsulotomy for the treatment of capsular block syndrome.

We present a novel use of femtosecond laser to treat capsular block syndrome (CBS) in a patient with dense opaque capsular block, who presented 16 years postcataract surgery. The extensive posterior capsular distension and densely opaque, milky fluid trapped behind the intraocular lens (IOL) prevented the use of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser posterior capsulotomy as primary treatment. Intra-operative optical coherence tomography enabled visualization of the posterior capsule and iris hooks were used to increase the pupillary diameter to enable femtosecond laser-assisted posterior capsulotomy to be performed in a minimally invasive technique. CBS was relieved successfully and Nd: YAG laser performed subsequently to remove residual posterior capsule opacification safely and with good visual outcomes. This method avoids risks associated with posterior vitrectomies and compromised IOL stability from inadvertent capsular bag damage, and adds to the expanding uses of femtosecond laser technology.

Femtosecond laser-assisted corneal transplantation with a low-energy, liquid-interface system.

Femtosecond laser-assisted keratoplasty has been proposed as a treatment option for corneal transplantation. In this study, we investigated and compared the outcomes of Ziemer Z8 femtosecond laser (FSL)-assisted penetrating keratoplasty (PK) using a liquid interface versus flat interface. Thirty fresh porcine eyes underwent FSL-assisted PK with the Z8 using different levels of energies (30%, 90% or 150%) and different interfaces (liquid or flat). The real-time intraocular pressure (IOP) changes, incision geometry, corneal endothelial damage, as well as the accuracy of laser cutting and tissue reaction, were performed and compared. We found that the overall average IOP at all laser trephination stages was significantly higher with the flat interface, regardless of the energy used (68.9 ± 15.0 mmHg versus 46.1 ± 16.6 mmHg; P < 0.001). The overall mean laser-cut angle was 86.2º ± 6.5º and 88.2º ± 1.0º, for the liquid and flat platform respectively, indicating minimal deviation from the programmed angle of 90º. When high energy (150%) was used, the endothelial denuded area was significantly greater with the flat interface than with liquid interface (386.1 ± 53.6 mm2 versus 139.0 ± 10.4 mm2 P = 0.02). The FSL cutting did not cause obvious tissue reaction alongside the laser cut on histological evaluation. The results indicated a liquid interface is the preferable choice in FSL-assisted corneal transplantation.

Proposal and validation of a new grading system for pterygium (SLIT2).

BACKGROUND/AIMS: To propose and validate a new pterygium grading system based on slit-lamp evaluation. METHODS: This prospective cross-sectional study included 217 patients with pterygium. All patients underwent slit-lamp examination, and slit-lamp photographs were independently graded by two graders twice. A total of eight parameters were evaluated and all parameters were assigned with a score of 1-4 (normal-severe). Intra-rater and inter-rater reliability as determined by weighted Cohen's kappa analysis. RESULTS: A total of 868 independent assessment, based on 217 slit-lamp images, were performed by two graders. For conjunctival assessment, the intra-rater reliability was excellent for body thickness (κ=0.81-0.89) and size at limbus (κ=0.87-0.92), substantial-to-excellent for body vascularity (κ=0.72-0.86), and moderate-to-excellent for body length (κ=0.57-0.81), whereas the inter-rater reliability was excellent for size at limbus (κ=0.86), substantial for body thickness (κ=0.72-0.73) and body vascularity (κ=0.66-0.75), and moderate for body length (κ=0.54-0.57). For corneal assessment, the intra-rater reliability was excellent for all four parameters (κ=0.84-0.90) whereas the inter-rater reliability was excellent for head length (κ=0.86-0.87), substantial-to-excellent for head vascularity (κ=0.78-0.82), substantial for Stocker's line (κ=0.79-0.80) and head thickness (κ=0.67-0.69). The grading system was named SLIT2, which included S tocker's line, S ize at limbus, L ength of head/body, I njection/vascularity of body/head, and T hickness of body/head. CONCLUSION: The proposed SLIT2 grading system, consisting of eight components, may serve as a reliable tool to standardise the reporting of pterygium severity and disease recurrence for clinical and research applications.

Long Term Outcomes of Surgical Excision of Giant Papillae with Mitomycin C and Amniotic Membrane Transplantation in the Treatment of Refractory Palpebral Vernal Keratoconjunctivitis.

Background and Objectives: To report the long-term outcomes of patients with refractory Vernal Keratoconjunctivitis (VKC) who underwent surgical excision of giant papillae (GP) with mitomycin C (MMC) 0.02% and amniotic membrane transplantation (AMT). Materials and Methods: This is a retrospective interventional single-center case series including five eyes of four patients who had refractory, symptomatic VKC with GP, along with corneal shield ulcers and/or punctate epithelial erosions. They underwent surgical excision of GP with MMC 0.02% alone (1 eye) or with MMC 0.02% and AMT (4 eyes). Their long-term visual and surgical outcomes were studied. Results: All subjects were male with bilateral involvement and mean age of presentation 9.8 years. The surgery was uneventful in all cases. Amongst the four eyes which underwent MMC with AMT, only one eye demonstrated papillary regrowth requiring repeat surgery. Postoperative follow-up ranged from 59 to 77 months (median 66 months). Four patients had the best corrected visual acuity (BCVA) >/= 6/9.5. One patient had BCVA 6/15 at the final follow-up due to the presence of anterior corneal stromal scar and poor ocular surface. Conclusions: Surgical excision of GP in combination with MMC and AMT, in refractory VKC, is a good treatment option with better clinical outcomes over a longer follow-up.

Lamellar Keratoplasty for Advanced Keratoconus.

Ectatic corneal diseases are a group of disorders resulting in progressive corneal steepening and thinning. Keratoconus, keratoglobus, pellucid marginal degeneration, post-keratorefractive ectasia, and corneal graft ectasia are the types of corneal ectasia. Early diagnosis with appropriate diagnostic tools can help prevent progression, eliminating the need for corneal transplantation. Lamellar or full thickness corneal transplantation are the treatment options for advanced diseases. Although the visual outcomes of penetrating keratoplasty are comparable to anterior lamellar keratoplasty (ALK) especially in keratoconus, ALK is the preferred treatment of choice considering benefits including reduced graft rejection, less long-term complications, and better graft survival. This article reviews the various surgical techniques in ALK with its clinical outcomes in advanced keratoconus.