RiTe conjugate mediated corneal collagen crosslinking, a novel therapeutic intervention for keratoconus - in vitro and in vivo study.

Corneal collagen crosslinking (CXL) is an effective method to halt the disease progression of keratoconus, a progressive corneal dystrophy leading to cone shaped cornea. Despite the efficacy of standard protocol, the concerning step of this procedure is epithelial debridement performed to facilitate the entry of riboflavin drug. Riboflavin, a key molecule in CXL protocol, is a sparsely permeable hydrophilic drug in corneal tissues. The present study has employed cell penetrating peptide (CPP), Tat2, to enhance the penetration of riboflavin molecule, and thereby improve currently followed CXL protocol. This study demonstrates approximately two-fold enhanced uptake of CPP riboflavin conjugate, Tat2riboflavin-5'Phosphate (RiTe conjugate), both in vitro and in vivo. Two different CXL protocols (Epi ON and Epi OFF) have been introduced and implemented in rabbit corneas using RiTe conjugate in the present study. The standard and RiTe conjugate mediated CXL procedures exhibited an equivalent extent of crosslinking in both the methods. Reduced keratocyte loss and no endothelial damage in RiTe conjugate mediated CXL further ascertains the safety of the proposed CXL protocols. Therefore, RiTe conjugate mediated CXL protocols present as potential alternatives to the standard keratoconus treatment in providing equally effective, less invasive and patient compliant treatment modality.

Management of traumatic displacement of LASIK flap.

Background: Although flap-based laser refractive surgeries are being extensively performed worldwide, complications due to the flap may occur years after the procedure leading to severe vision-threatening complications. Purpose: To describe the management of a case of traumatic displacement of a LASIK flap performed 8 years earlier. Synopsis: A 42-year-old male presented to us with complaints of decreased vision in his left eye following trauma with a toy gun sustained a day earlier. His best-corrected visual acuity was Counting fingers @ 2 m, and a slit-lamp evaluation revealed a LASIK flap with its temporal edge folded inwards. Flap repositioning was planned. The final surgical plan was interface irrigation with mechanical debridement, alcohol epitheliectomy, fibrin glue application, and bandage contact lens. His uncorrected visual acuity improved to 6/6, N6 at 5 weeks postoperatively, which was maintained at 8 months postoperatively along with a clear interface. Highlights: Traumatic displacement of LASIK flap years after the procedure is a known complication. However, simple flap repositioning may lead to various complications like epithelial ingrowth, DLK, astigmatism, etc., This video describes how to achieve anatomical and visual rehabilitation in such eyes without any long-term complications. Video link: https://youtu.be/QtWG9hEMsXM.

Corneal blindness and eye banking: Current strategies and best practices.

Corneal blindness (CB) is one of the leading causes of blindness in India and globally, affecting around 8 million population worldwide. Many of these corneal blind patients may be visually rehabilitated by corneal transplantation (CT). Eye banking plays a crucial role in facilitating CT and ocular research. Many countries have adopted regulatory frameworks, quality assurance programs, and technological advancements to enhance the efficacy and safety of CT. Various infrastructural and organizational frameworks of eye banks (EBs) in India, according to the Eye Bank Association of India (EBAI), aid in establishing guidelines and standards for EB practices. Initiatives such as the National Programme for Control of Blindness (NPCB) have significantly contributed to eye donation rates and improved access to donor corneas. This review article discusses the established eye banking networks in countries such as India, the United States (USA), and Europe, where dedicated EB organizations work collaboratively to ensure efficient procurement, processing, and distribution of corneal tissue. It also highlights specific strategies employed in India and global countries to address EBs' challenges. These challenges include the shortage of donor corneas, improving donor screening and tissue processing techniques, ensuring timely distribution of corneal tissue, and maintaining high-quality standards. Interestingly, the comparative analysis between India and other developed countries highlights the similarities and differences in eye banking strategies. By understanding the strategies employed by different regions, EBs can learn from each other's experiences and work toward achieving optimal outcomes in CT and ocular research worldwide. It underscores the importance of knowledge sharing and collaborative efforts in addressing common challenges and implementing best practices in eye banking.

Oral mucous membrane grafting for unilateral lid margin keratinization following radiotherapy.

We describe the outcomes of oral mucous membrane grafting as a surgical technique for unilateral lid margin keratinization following radiotherapy. A 47-year- old woman presented with an 8-month history of a white spot in her right eye. She had a history of adenoid cystic carcinoma of the right spheno-ethmoid sinus, for which she underwent radiotherapy. Slit-lamp evaluation revealed lid margin keratinization of the right upper and lower eyelids and a keratin plaque on the corneal surface. We performed excision of the keratin plaque and lid margin keratinization, followed by oral mucous membrane grafting of the upper and lower eyelid margins. Histopathological evaluation of the excised lid margin revealed keratinized stratified squamous epithelium, consistent with lid margin keratinization. The corneal surface and lid margins showed no recurrent keratin deposition at the final follow-up, 11 months postoperatively.

Corneal scarring following collagen cross-linking: evidence of increased lysyl oxidase activity.

PURPOSE: To report a case of corneal scarring following collagen cross linking in a young female. METHODS: A 24-year-old female presented to us with complaints of decreased vision and a white spot in her left eye following collagen cross linking (CXL) performed elsewhere, four years prior. We diagnosed her as a case of left eye leucomatous corneal opacity for which she underwent optical penetrating keratoplasty under local anaesthesia. The excised corneal tissue was evaluated by routine histopathology and immunohistochemistry. RESULTS: At the final follow up visit, one year following corneal transplantation, her visual acuity improved to 20/20, J1 with a clear graft. CONCLUSION: Vision threatening corneal scarring may be rarely noted following CXL.

Amniotic Membrane Grafting for Ocular Surface Inflammation Following Topical Interferon Alpha 2b Therapy.

We describe a rare case of a 58-year-old female with ocular surface squamous neoplasia (OSSN) in her left eye. She was treated for 12 months with topical interferon alpha-2b (IFNα-2b) eye drops and OSSN resolved completely. She presented with a whitish elevated lesion involving the cornea, limbus, and conjunctival surface after discontinuation of topical IFNα-2b. Excision biopsy along with amniotic membrane grafting was done to stabilize the ocular surface. Histopathological evaluation of the excised tissue revealed ocular surface inflammation with no evidence of malignancy.

Novel corneal targeting cell penetrating peptide as an efficient nanocarrier with an effective antimicrobial activity.

Delivery of therapeutics to the ocular tissues is challenging due to various anatomical and physiological barriers imposed. Cell penetrating peptides (CPPs) have emerged as potent drug nanocarriers that have been shown to overcome these barriers and enhance bioavailability of therapeutic macromolecules in deep ocular tissues. In the present study, an ocular targeting CPP has been designed by exploring potential targets of anterior ocular tissues in particular receptors, transporters and glycosaminoglycans (GAGs). The novel 11 mer peptide sequence, Corneal Targeting Sequence 1 (CorTS 1), has been developed by modifying leucine rich repeat (LRR) motif ensuring that it interacts with small leucine rich proteoglycans and collagen present in the corneal stroma. CorTS 1 exhibited dose dependent cellular translocation from 5 µM in Human Corneal Epithelial cell line (HCE) with no cytotoxicity. CorTS 1 was also found to deliver protein cargo inside HCE cells. Ex vivo tissue penetration study of CorTS 1 demonstrated in goat eyes revealed an augmented accumulation of peptide in the stromal region of cornea than in aqueous humor. Interestingly, CorTS 1 showed an antimicrobial activity against MRSA and Fusarium dimerum. Therefore, CorTS 1 can be a promising candidate with dual traits of antimicrobial agent and nanocarrier for ocular drugs.

Enhanced in vivo antifungal activity of novel cell penetrating peptide natamycin conjugate for efficient fungal keratitis management.

Natamycin is the only FDA approved drug that is used as a first line of treatment for fungal keratitis caused by filamentous fungi, however natamycin is known for poor corneal penetration. Cell penetrating peptides (CPPs) are emerging nanocarriers for the enhanced delivery of various macromolecules owing to their distinct cellular translocation ability. In the present study, tissue penetration ability and antifungal efficacy of CPP (Tat2) conjugated natamycin has been investigated and compared with natamycin alone in vivo. Results show that Tat2natamycin exhibits five- fold higher ocular penetration than natamycin alone when given topically. Complete resolution of fungal keratitis in 44% of the animals in Tat2natamycin treated group as compared to only 13% of the animals in natamycin treated group further highlights its increased antifungal efficacy. Hence, this conjugate is a promising antifungal molecule with enhanced ocular penetration as well as antifungal efficacy against selected fungal species.

Cell penetrating peptides as efficient nanocarriers for delivery of antifungal compound, natamycin for the treatment of fungal keratitis.

PURPOSE: Enhancing the penetration ability of the antifungal drug natamycin, known to possess poor penetration ability through the corneal epithelium, by complexing with cell penetrating peptides. METHODS: The drug, natamycin was conjugated to a cell penetrating peptide, Tat-dimer (Tat2). The uptake ability of the conjugate in human corneal epithelial cells and its antifungal activity against filamentous fungi, F.solani has been elucidated. RESULTS: The cellular penetration ability of natamycin increased upon conjugation with Tat2. The conjugation between natamycin and Tat2 also lead to enhanced solubility of the drug in aqueous medium. The antifungal activity of the conjugate increased two- folds in comparison to unconjugated natamycin against clinical isolates of F.solani. CONCLUSION: The formation of CPP-natamycin complex is clinically significant as it may enhance the bioavailability of natamycin in corneal tissues and aid in efficient management of fungal keratitis.

Exaggerated subepithelial fibrosis after anterior stromal puncture presenting as a membrane.

PURPOSE: The aim of the study was to describe the clinical features, histopathological findings, and management of eyes presenting with a thick membrane after anterior stromal puncture (ASP) for bullous keratopathy. STUDY DESIGN: Retrospective interventional case series. METHODS: Retrospective chart analysis of 3 eyes presenting with a thick membrane between 12-30 months after ASP was done. Patients presented with complaints of recurrent symptoms of pain, watering, and irritation. The membrane was peeled off from the corneal surface in the operation room and sent for histopathological evaluation. A cryopreserved amniotic membrane was secured on the corneal surface using 10-0 nylon interrupted sutures. RESULTS: Patients reported alleviation of symptoms after the procedure and remained asymptomatic at the final follow-up (range 6-12 months). Histopathological evaluation of the excised membrane revealed the presence of a hyperplastic epithelium with loose fibrocollagenous tissue suggestive of subepithelial fibrosis. CONCLUSIONS: Subepithelial fibrosis after ASP, although a known entity, may rarely present as a thick membrane because of exaggerated response resulting in the recurrence of symptoms. This can be successfully managed by superficial keratectomy and amniotic membrane transplant.