Treatment of corneal perforation with lenticules from small incision lenticule extraction surgery: a preliminary study of 6 patients

Long-term results of allogenic corneal lenticule of hyperopic SMILE for post-LASIK ectasia

Post-laser-assisted in situ keratomileusis (LASIK) corneal ectasia is a severe complication of corneal refractive surgery, and cryopreserved lenticules from hyperopic small incision lenticule extraction (SMILE) may offer a promising treatment though their long-term safety and efficacy are still under investigation. In this prospective case series, six eyes from six patients with post-LASIK ectasia received lenticules (mean cryopreserved time: 63 days). The procedure involved lifting the corneal flap, implanting the lenticule, and repositioning the flap. Over a follow-up period of at least one year, uncorrected distance visual acuity (UDVA) improved from 1.52 ± 0.40 preoperatively to 0.74 ± 0.28 LogMAR. Two eyes gained one line of corrected distance visual acuity (CDVA), three gained two lines, and one gained over three lines. Spherical equivalents decreased from -14.67 ± 2.36 D to -8.75 ± 4.03 D (p = 0.02). Mean anterior K and total corneal refractive power decreased (p < 0.05). Thinnest corneal thickness increased from 359.2 ± 39.3 μm to 401.7 ± 53.4 μm (p = 0.02). These findings support the potential of cryopreserved lenticules for treating post-LASIK ectasia, though further refinement in refractive predictability is needed.

Treatment of Corneal Dermoid with Fibrin Glue Boned Multi-Layer Lenticules from Small Incision Lenticules Extraction Surgery: A Preliminary Study of Five Patients

PURPOSE

Dermoid excision combined with lamellar keratoplasty was one of the most common surgical techniques for corneal dermoid. Due to the huge shortage of corneal donors, small incision lenticule extraction (SMILE) derived lenticules might be the novel and feasible corneal grafts instead of traditional corneal donors. Therefore, we tried to use FG boned multi-layer lenticules as grafts in the treatment of corneal dermoid.

METHODS

Five patients (the oldest patient was 54 years old and the youngest case was 5 years old) were diagnosed with corneal dermoid and complaining of blurred vision or unsatisfied cosmetic appearance. All patients underwent corneal dermoid excision combined with FG boned multi-layer corneal lenticules transplantation. Slit-lamp microscopy and anterior-segmental optical coherence tomography(AS-OCT)were used to observe ocular appearance, corneal grafts survival, epithelialization, transparency, interlamellar fluid accumulation and the degradation of FG. The preoperative and postoperative change of best-corrected visual acuity (BCVA) and astigmatism were respectively recorded.

RESULTS

All patients were satisfied with the postoperative cosmetic results. BCVA had been increased and astigmatism had been decreased in all cases. We observed that the FG boned multi-layer corneal lenticules were covered with smooth corneal epithelium in one week after transplantation and successfully adhered to the corneal beds, without any dislocation or interlayer separation. FG was gradually degraded and absorbed within 1 month after surgery. The lenticule grafts grew well without rejection and kept transparency during the follow-up period.

CONCLUSIONS

FG boned multi-layer lenticules would be the novel and feasible substitute for lamellar keratoplasty in the treatment of corneal dermoid. FG could not be only used as binder adhering multi-layer lenticules, closing the interlayer space of multi-layer lenticules, preventing the formation of interlayer fluid, but also increasing the thickness and toughness of lenticules, and therefore which is more facilitate to intraoperative suture.

Banking of post-SMILE stromal lenticules for additive keratoplasty: A new challenge for eye banks?

PURPOSE

ReLEx (Refractive Lenticule Extraction) Small Incision Lenticule Extraction (SMILE), the second generation of ReLEx Femtosecond Lenticule Extraction (FLEx), is a minimally invasive, flapless procedure designed to treat refractive errors such as myopia, hyperopia, presbyopia, and astigmatism. This review aims to provide a comprehensive overview of the methods for preserving SMILE-derived lenticules and discusses their potential future applications.

METHODS

A narrative literature review was conducted using PubMed, Scopus, and Web of Science databases, focusing on articles published up to January 2024 and available in English. The authors also evaluated the reference lists of the collected papers to identify any additional relevant research.

RESULTS

No standardized protocols currently exist for the storage or clinical application of SMILE-derived lenticules. However, these lenticules present a promising resource for therapeutic uses, particularly in addressing the shortage of donor corneal tissues. Their potential applications include inlay and overlay additive keratoplasty, as well as other ocular surface applications. Further research is needed to establish reliable protocols for their preservation and clinical use.

CONCLUSION

SMILE-derived lenticules offer significant potential as an alternative to donor corneal tissues. Standardizing their storage and application methods could enhance their use in clinical settings.

Biologicals and Biomaterials for Corneal Regeneration and Vision Restoration in Limbal Stem Cell Deficiency

The mammalian cornea is decorated with stem cells bestowed with the life-long task of renewing the epithelium, provided they remain healthy, functional, and in sufficient numbers. If not, a debilitating disease known as limbal stem cell deficiency (LSCD) can develop causing blindness. Decades after the first stem cell (SC) therapy is devised to treat this condition, patients continue to suffer unacceptable failures. During this time, improvements to therapeutics have included identifying better markers to isolate robust SC populations and nurturing them on crudely modified biological or biomaterial scaffolds including human amniotic membrane, fibrin, and contact lenses, prior to their delivery. Researchers are now gathering information about the biomolecular and biomechanical properties of the corneal SC niche to decipher what biological and/or synthetic materials can be incorporated into these carriers. Advances in biomedical engineering including electrospinning and 3D bioprinting with surface functionalization and micropatterning, and self-assembly models, have generated a wealth of biocompatible, biodegradable, integrating scaffolds to choose from, some of which are being tested for their SC delivery capacity in the hope of improving clinical outcomes for patients with LSCD.

Chemical, Physical, and Biological Corneal Decellularization Methods: A Review of Literature

The cornea is one of the most commonly transplanted tissues worldwide. It is used to restore vision when severe visual impairment or blindness occurs in patients with corneal diseases or after trauma. Due to the global shortage of healthy donor corneas, decellularized corneal tissue has significant potential as an alternative to corneal transplantation. It preserves the native and biological ultrastructure of the cornea and, therefore, represents the most promising scaffold. This article discusses different methods of corneal decellularization based on the current literature. We searched PubMed.gov for articles from January 2009 to December 2023 using the following keywords: corneal decellularization, decellularization methods, and corneal transplantation. Although several methods of decellularization of corneal tissue have been reported, a universal standardised protocol of corneal decellularization has not yet been introduced. In general, a combination of decellularization methods has been used for efficient decellularization while preserving the optimal properties of the corneal tissue.

Corneal stromal lenticule transplantation for the treatment of corneal ulcers

PURPOSE

To evaluate the safety and efficacy of using corneal stromal lenticules (CSLs) obtained during refractive surgery Refractive Lenticule Extraction (ReLEx) with the Small Incision Lenticule Extraction (SMILE) procedure for the treatment of corneal ulcers.

METHODS

This retrospective study included 12 eyes of 12 patients, 7 men and 5 women with varying degrees of corneal ulcer. The mean age was 64 ± 18 (range 34 to 95 years). The monitoring included corrected distance visual acuity (CDVA), slit-lamp biomicroscopy examination, a Seidel test, stability of the graft and anterior segment optical coherence tomography (AS-OCT) inspection. Patients were closely monitored for possible postoperative complications for at least 6 months.

RESULTS

In 7/12 (58%) eyes, the corneal ulcer was successfully sealed with CSL and amniotic membrane (AM) without the need for any additional surgical intervention. In 3 eyes, penetrating keratoplasty (PK) was needed in addition to CSL transplantation and in 2 eyes the scleral patch was used to fully seal after CSL transplantation. During the follow-up period no signs of rejection or infection were detected in any patient.

CONCLUSION

The use of CSLs from ReLEx SMILE may be considered as an alternative method for the treatment of corneal ulcers before a more extensive and definitive solution - PK - is used. Our preliminary findings suggest that properly performed CSL transplantation using cryopreserved lenticules is a safe and effective method to temporarily cover the corneal partial-thickness defect or even perforation.

Study on the biological properties of SMILE-derived corneal stromal lenticules after long-term cryopreservation in nutrient capsules

PURPOSE

To investigate the long-term preservation effects of nutrient capsules on the physiological activity, collagen fiber structure and transmittance of corneal stromal lenticules derived from small incision lenticule extraction (SMILE).

METHODS

A new nutrient capsule was constructed for long-term preservation of SMILE-derived corneal stromal lenticules. The lenticules were randomly divided into 99% anhydrous glycerol, and hydrogel nutrient capsules. After preserving for 1 year at -80 °C, lenticules were compared with fresh lenticules. The optical transmittance, tissue morphology, ultrastructure, cells activity and immunogenicity of the lenticules was detected and compared between different groups.

RESULTS

The rate of apoptotic cells was significantly higher in the glycerol group compared with the nutrient capsule group (P < 0.0001). More viable cells were present in the lenticules after nutrient capsule preservation compared to the glycerol group (P = 0.0003). The mean transmittance of the lenticules in the glycerol group (50 ± 18%) was significantly lower (P = 0.0008) compared to the control group (75 ± 11%), and the lenticules transmittance of the nutrient capsule group (64 ± 15%) after long-term preservation was not significantly different (P = 0.23) compared to the control group. The structure of HE staining showed that the collagen fibers in the nutrient capsule group were arranged in parallel and neatly, and a few cavitation vesicles were visible inside the tissue. There was no significant difference in the number of lenticular collagen fibers in the nutritional capsule group compared to the fresh lenticule group (P = 0.06). HLA-DR, HLA-ABC, CD45, CD25 and CD69 expression was low in all groups of lenticules after preservation.

CONCLUSIONS

Nutrient capsules can preserve lenticules for a long time and maintain the transmission structure and cells activity of lenticules.

Epithelial thickness remodeling after small incision lenticule intrastromal keratoplasty in correcting hyperopia measured by RTVue OCT

PURPOSE

To characterize the in vivo corneal epithelial thickness (CET) remodeling profile in a population of eyes after small incision lenticule intrastromal keratoplasty (SMI-LIKE) for hyperopia.

METHODS

The CET profile was measured by RTVue-100 Fourier-domain OCT system across the central 6-mm diameter of the cornea of 17 eyes from 12 subjects (five males and seven females) who accepted corneal stromal lens implantation surgery for correcting hyperopia. The CET were measured at positions with a radius of 0-1.0 mm, 1.0-2.5 mm (divided into eight quadrants) and 2.5-3.0 mm (divided into eight quadrants) from the corneal center. Corneal maximum simulated keratometry (Km) was measured by Pentacam HR anterior segment analyzer to analyze CET changes. The examination data of subjects were collected in four time periods, which were preoperative, short-term postoperative (one week after surgery), mid-term postoperative (the last review within 3-6 months after surgery), and long-term postoperative (the last review over 1-2.5 years after surgery). The changes of CET were compared and analyzed in the four time periods.

RESULTS

Mean CET in 0-1.0 mm, 1.0-2.5 mm and 2.5-3.0 mm of the cornea decreased in one week after surgery, respectively, as compared to CET in the preoperative period, which turned from 55.06 ± 0.82 μm、54.42 ± 0.75 μm、53.46 ± 0.60 μm to 51.18 ± 1.05 μm (P = 0.005), 49.38 ± 0.70 μm (P = 0.000), 51.29 ± 0.59 μm (P = 0.025). In the mid-term postoperative period, mean CET in 0-1.0 mm and 1.0-2.5 mm areas kept thinner than mean CET in the preoperative period, CET in 0-1.0 mm is 50.59 ± 0.76 μm (P = 0.000),CET in 1.0-2.5 mm is 50.23 ± 0.57 μm (P = 0.000), while mean CET in 2.5-3.0 mm area recovered to the same thickness as the preoperative level, which is 54.36 ± 0.66 μm (P = 1.000), until the long-term period, CET stabilized in the above doughnut pattern.

CONCLUSIONS

After stromal lenticule implantation for hyperopia, CET showed a remodeled form of thinning in the 0-2.5 mm area and thickening in the 2.5-3.0 mm area, and remained stable within one year after surgery.

The new future perspective in corneal tissue utilisation - methods of preparation and preservation

PURPOSE

The goal of our study is to find an optimal approach to the preparation and preservation of corneal stromal tissue. We want to compare different methods of corneal stromal tissue creation and storage to optimize the efficacy of this process under the conditions of an eye bank. After we find the most suitable method to create a safe high quality product, we want to prove the possibility of using a single donor cornea for more than one patient. We would also like to verify the feasibility of making more corneal lenticules after the removal of a corneal endothelium for DMEK transplantation.

METHODS

We provided morphological (histology, scanning electron microscope) and microbiological analysis in order to compare different methods of corneal lenticule and corneal stromal lamellae preparation and preservation. We also tested the surgical handling of the tissue to secure a safe manipulation of the tissue for clinical use. We compared two methods of corneal lenticule preparation: microkeratome dissection and femtosecond laser. As methods of preservation, we tested hypothermia, cryopreservation at -80 degrees Celsius in DMSO (dimethyl sulfoxide) and storage at room temperature with glycerol. Some intrastromal lenticules and lamellae in each group were previously irradiated with gamma radiation of 25 kGy (KiloGray).

RESULTS

Corneal stromal lamellae prepared with a microkeratome have a smoother cut - side surface compared to lamellae prepared with a femtosecond laser. Femtosecond laser preparation caused more irregularities on the surface and we detected more conglomerates of the fibrils, while lamellae made with microkeratome had more sparse network. Using femtosecond laser, we were able to make more than five lenticules from a single donor cornea. Gamma irradiation led to damage of collagen fibrils in corneal stroma and a loss of their regular arrangement. Corneal tissue stored in glycerol showed collagen fibril aggregates and empty spaces between fibrils caused by dehydration. Cryopreserved tissue without previous gamma irradiation showed the most regular structure of the fibrils comparable to storage in hypothermia.

CONCLUSION

Our results suggest that formation of a corneal lenticule lamellae by microkeratome results in smoother corneal lenticules, while being much cheaper than formation by femtosecond laser. Gamma irradiation of 25 kGy caused damage of the collagen fibres as well as their network arrangement, which correlated with loss of transparency and stiffer structure. These changes impair possible surgical utilisation of gamma irradiated corneas. Storage in glycerol at room temperature and cryopreservation had similar outcomes and we believe that both methods are appropriate and safe for further clinical use .

Update of Research Progress on Small Incision Lenticule Extraction (SMILE) Lenticule Reuse

The SMILE lenticule is a complete corneal stroma that is removed from SMILE surgery. Since the increasing number of SMILE surgeries, a large number of SMILE lenticules have been produced, so the reuse and preservation of the stromal lens has become a research hotspot. Due to the rapid development of the preservation and clinical reuse of SMILE lenticules, there have been many related studies in recent years, so we updated it on this basis. We searched PubMed, Web of Science, Embase, Elsevier Science, CNKI, WANFANG Data and other databases for all articles published on the preservation and clinical reuse of SMILE lenticules, screened useful articles, selected relevant articles published in the last five years as the main body for summary, and then reached a conclusion. The existing preservation methods of SMILE lenticule include Moist chamber storage at low temperature, cryopreservation technique dehydrating agent and corneal storage medium, which have their own advantages and disadvantages. Presently, smile lenticules can be used for the treatment of corneal ulcers and perforations, corneal tissue defects, hyperopia, presbyopia and keratectasia, which have been proven to be relatively effective and safe. More research on smile lenticule reuse needs to be carried out to confirm its long-term efficacy.

Use of Decellularized SMILE (Small-Incision Lenticule Extraction) Lenticules for Engineering the Corneal Endothelial Layer: A Proof-of-Concept

PURPOSE

To demonstrate the suitability of using decellularized SMILE (Small-incision Lenticule Extraction) lenticules for culturing and transplanting the corneal endothelium (CE).

METHODS

The SMILE lenticules, obtained during refractive surgery, were decellularized by incubating in CE culture medium and fetal bovine serum. Decellularization was confirmed by hematoxylin and eosin staining, DAPI staining, and gel electrophoresis. The amount of DNA per milligram of dry tissue weight was calculated to quantify the residual nuclear content. The transparency of the decellularized lenticules was determined by calculating the modulation transfer function. Immunostaining for stromal collagens and glycosaminoglycan was performed using specific antibodies. Engineered tissue was constructed by culturing the CE cells on lenticules and staining for ZO-1, Na/K ATPase, and N-cadherin. The functionality of the engineered tissues was assessed by transplanting them onto edematous human donor corneas and perfusing for 10 days ex-vivo.

RESULTS

The residual DNA per milligram of dry tissue weight was found to be significantly reduced (p < 0.0001) in serum (0.255 µg/mg) and Opti-MEM (0.140 µg/mg) when compared to fresh lenticules (3.9 µg/mg). Decellularization did not alter the arrangement of the collagen fibers or the transparency of the lenticules. CE cells attached and matured to express ZO-1, Na/K ATPase, and N-cadherin at two weeks after seeding. The engineered tissue upon transplantation significantly reduced the corneal edema (p < 0.05) and the transplanted cells remained intact on the SMILE lenticule post-transplantation.

CONCLUSION

This study demonstrates the suitability of using SMILE lenticules decellularized using a simple, chemical-free method for engineering the corneal endothelium for transplantation.

Carbodiimide crosslinked decellularized lenticules as a drug carrier for sustained antibacterial eye treatments

In this study, the drug-loading and antibacterial activity of carbodiimide/N-hydroxysuccinimide (EDC/NHS) crosslinked decellularized lenticules (CDLs) were evaluated. Small incision lenticule extraction derived lenticules were decellularized and modified with crosslinking concentrations of 0.00 (E/L00, non-crosslinked), 0.01 (E/L01), 0.05 (E/L05) and 0.25 mmol (E/L25) EDC per mg lenticules at 5:1 EDC/NHS ratios with non-decellularized non-crosslinked lenticules (NDLs) as controls. NDLs and EDC/NHS CDLs had similar water contents. The light transmittance percentages (400-800 nm) were 91.55 ± 1.16%, 88.68 ± 1.19%, 80.86 ± 1.94%, 85.12 ± 2.42% and 85.62 ± 2.84% for NDLs, E/L00, E/L01, E/L05 and E/L25, respectively (P< 0.01). The EDC/NHS CDLs (diameter: 6.36 ± 0.18 mm; central thickness: 117.31 ± 3.46 μm) were soaked in 3% (wt./vol.) levofloxacin (LEV) solution for 3 h. The drug release concentrations of LEV-impregnated EDC/NHS CDLs were determined by high-performance liquid chromatography. Zone inhibition (ZOI) againstStaphylococcus aureusof E/L01, E/L05 and E/L25 were superior to E/L00 CDLs (P< 0.01) and among the different crosslinked groups, E/L05 lenticules produced the largest ZOIs and their drug concentration release over 21 d was the highest. EDC/NHS crosslinking can improve the drug-loading effect and antibacterial activity of decellularized lenticules. LEV-impregnated EDC/NHS CDLs are promising drug delivery carriers.

SMILE lenticule versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcer

PURPOSE

To evaluate the safety and efficacy of stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery versus amniotic membrane graft (AMG) augmented with platelet-rich plasma (PRP) for the treatment of perforated corneal ulcers and compare the results between the two groups.

PATIENTS AND METHODS

This is a comparative retrospective study that included 40 eyes with medium-sized corneal perforations, which were classified into two equal groups of 20 eyes each; group (A) was treated with SMILE lenticule graft and group (B) was treated with AMG augmented with PRP. Pre- and postoperative evaluations were carried out using both slit-lamp (SL) examination and anterior segment optical coherence tomography (AS-OCT), including closure of perforation, complete healing, and best corrected visual acuity (BCVA).

RESULTS

Complete closure of the perforation was achieved in both groups. However, healing was faster in the SMILE lenticule group than in the AMG with PRP group (P < 0.05). Complete healing was achieved in both groups: 100% in SMILE lenticule group and 95% in AMG with PRP group (P > 0.05). Both groups had few insignificant complications (30% in each), which were managed.

CONCLUSION

Both methods achieved adequate healing of corneal perforations within few weeks without significant complications. However, the stromal lenticule obtained from small-incision lenticule extraction (SMILE) surgery tended to be safer with faster healing than AMG with PRP.

Bioengineered Human Stromal Lenticule for Recombinant Human Nerve Growth Factor Release: A Potential Biocompatible Ocular Drug Delivery System

Small incision lenticule extraction (SMILE), is a surgical procedure for the myopia correction, during which a corneal stromal lenticule is extracted. Given that we have previously demonstrated how this discarded tissue could be repurposed as a bio-scaffold for stromal engineering, this study aimed to explore its use as an ocular drug delivery system of active molecules, using neurotrophic factor Nerve Growth Factor (NGF). We employed human stromal lenticules directly collected from healthy donors undergoing SMILE. Following a sodium dodecylsulfate (SDS) treatment, decellularized lenticules were incubated with a suspension of polylactic-co-glycolic-acid (PLGA) microparticles (MPs) loaded with recombinant human NGF (rhNGF-MPs). Fluorescent MPs (Fluo-MPs) were used as control. Data demonstrated the feasibility to engineer decellularized lenticules with PLGA-MPs which remain incorporated both on the lenticules surface and in its stromal. Following their production, the in vitro release kinetic showed a sustained release for up to 1 month of rhNGF from MPs loaded to the lenticule. Interestingly, rhNGF was rapidly released in the first 24 h, but it was sustained up to the end of the experiment (1 month), with preservation of rhNGF activity (around 80%). Our results indicated that decellularized human stromal lenticules could represent a biocompatible, non-immunogenic natural scaffold potential useful for ocular drug delivery. Therefore, combining the advantages of tissue engineering and pharmaceutical approaches, this in vitro proof-of-concept study suggests the feasibility to use this scaffold to allow target release of rhNGF in vivo or other pharmaceutically active molecules that have potential to treat ocular diseases.

Effects of Corneal Stromal Lens Collagen Cross-Linking Regraft on Corneal Biomechanics

Background

Corneal collagen cross-linking (CXL) therapy, a method that uses a combination of riboflavin and ultraviolet-A light (UVA), can promote the formation of covalent cross-linking of amino acid residues of corneal collagen and enhance the hardness of the cornea. In this study, we explored the effects of corneal stromal lens collagen cross-linking regraft on corneal biomechanics.

Methods

A total of 15 New Zealand white rabbits were divided into 3 groups: normal control group (group A), SMILE + uncross-linked lens implantation group (Group B), and SMILE + cross-linking lens implantation group (group C). The design parameters of SMILE surgery were as follows: the corneal cap was 120 um thick, the lens diameter was 6.5 mm, and the diopter was -6.0D. Riboflavin and ultraviolet-A (UVA) were used as corneal stromal lens CXL, which was implanted into the allogeneic rabbit corneal stromal bag 24 hours after the operation. Postoperative corneal thickness (CCT), refraction, AS-OCT, and corneal biomechanics were performed before and then at 1 and 3 months after the operation.

Results

All corneas appeared transparent and smooth 3 months after surgery. The corneal thicknesses of both group B and group C were lower than those before the operation. The corrected refraction of group B and group C after lens implantation was also lower than the expected corrected power; there was no significant difference between the two groups (P > 0.05). AS-OCT results showed an uneven surface and thickness of the corneal stromal lens in two eyes of group B. Moreover, corneal elastic deformation increased with intraocular pressure in each group; displacement from large to small was group B > group C and > group A. The creep from large to small was group B > group C > group A. The fiberboard layers of groups B and C were disordered, and there were a few autophagosomes in the fibroblasts of group B by transmission electron microscopy (TEM).

Conclusions

Allograft graft of corneal stromal lens collagen cross-linked can significantly increase the biomechanical properties of the cornea.

Effect of SMILE-derived decellularized lenticules as an adhesion barrier in a rabbit model of glaucoma filtration surgery

Background

To investigate the effects of small incision lenticule extraction (SMILE)-derived decellularized lenticules on intraocular pressure (IOP) and conjunctival scarring in a rabbit model of glaucoma filtration surgery.

Methods

Trabeculectomy was performed on both eyes of New Zealand rabbits. A decellularized lenticule was placed in the subconjunctival space in one eye of the rabbits (the decellularized lenticule group), and no adjunctive treatment was performed in the fellow eye (the control group). The filtering bleb features and IOP were evaluated 0, 3, 7, 14, 21, and 28 days after surgery, and histopathologic examination was performed 28 days after surgery.

Results

Decellularized lenticules significantly increased bleb survival and decreased IOP postoperatively in the rabbit model with no adverse side effects. The histopathologic results showed a larger subconjunctival space and less subconjunctival fibrosis in the decellularized lenticule group.

Conclusions

Decellularized lenticules can prevent postoperative conjunctiva-sclera adhesion and fibrosis, and they may represent a novel antifibrotic agent for trabeculectomy.

Risk Evaluation of Human Corneal Stromal Lenticules From SMILE for Reuse

PURPOSE

To investigate the pathogenicity and immunogenicity of human corneal stromal lenticules from small incision lenticule extraction (SMILE).

METHODS

Serological testing was completed prior to sample collection to rule out infectious diseases. Pathogens herpes simplex viruses (HSV) type 1 and type 2 were screened for by real-time fluorescent quantitative polymerase chain reaction, and bacteria, fungi, and Acanthamoeba from 128 lenticules of 64 patients were cultured. A total of 132 lenticules from 93 patients were randomly assigned to the fresh group, -78 °C anhydrous glycerol preservation group (glycerol group), and 0.1% sodium dodecyl sulfate decellularization group (SDS group) in pairs and detected by immunohistochemistry, Western blot, transmission electron microscopy, transmittance, and nanoindentation.

RESULTS

The fresh lenticules were all negative for HSV-1, HSV-2, bacteria, fungi, and Acanthamoeba. HLA-I A/B/C and HLA-II DR antigens were all expressed in fresh lenticules but were clearly reduced after preservation at -78 °C in anhydrous glycerol or decellularization in 0.1% SDS. The collagen fibers of the lenticules in the fresh group were regularly arranged, and the keratocytes were intact. The fibers in the glycerol group were regularly arranged, and the integrity of keratocytes was destroyed. The fibers in the SDS group were disordered and had no cellular structure. The transmittance and Young's modulus were highest in the fresh group, lower in the glycerol group, and lowest in the SDS group.

CONCLUSIONS

Risk of infection is low, but risk of rejection exists on the reuse of fresh human corneal stromal lenticules from SMILE. Anhydrous glycerol preservation at -78 °C is an ideal method for reducing antigens without damaging the structure and function of lenticules. [J Refract Surg. 2021;37(1):32-40.].

Treatment of Mooren's ulcer coexisting with a pterygium using an intrastromal lenticule obtained from small-incision lenticule extraction: case report and literature review

The coexistence of Mooren’s ulcer and a pterygium is an extremely rare ocular condition that has been infrequently reported in the literature to date. We herein present the first case of treatment of Mooren’s ulcer coexisting with a pterygium using a lenticule obtained by myopic small-incision lenticule extraction (SMILE). A 61-year-old woman presented with a 3-month history of recurrent ocular pain and red eye caused by Mooren’s ulcer coexisting with a pterygium. She received topical immunosuppressive and anti-infection treatments for almost 3 months. However, her ocular symptoms and signs did not substantially improve. Therefore, we performed lamellar keratoplasty with a corneal lenticule obtained by SMILE, followed by pterygium excision combined with conjunctival autografting. The patient recovered well with no complications or recurrence 1 year postoperatively. Our success suggests that combined surgery may be an effective management for coexistence of Mooren’s ulcer and a pterygium if conservative treatments fail. A corneal lenticule obtained by SMILE can be used as the lamellar keratoplasty graft in such patients.

Tectonic keratoplasty using small incision lenticule extraction-extracted intrastromal lenticule for corneal lesions

Objective

This study investigated an alternative approach for obtaining donor corneas for keratoplasty that can be used in nations with high corneal demand and high costs for treatment of non-healing ulcers or lesions.

Methods

Eighteen patients (18 eyes) who underwent tectonic keratoplasty using small incision refractive lenticule extraction (SMILE)-extracted lenticule were included. Data were recorded regarding age, corneal status, corneal lesion location and size, preoperative and postoperative visual acuity, lenticule layer, and additional medical history.

Results

Corneal thinning and corneal perforation in 13 and 5 patients, respectively, were treated with tectonic keratoplasty using SMILE-extracted lenticule. After tectonic keratoplasty, globe integrity was maintained in 16 of the 18 patients. The mean decimal visual acuity improved from 0.2555±0.3326 preoperatively to 0.3303±0.3487 at the final follow-up. Visual acuity improvement was greater in patients with corneal perforation than in patients with corneal thinning. In addition, visual acuity was most improved in patients with infratemporal lesions.

Conclusion

Tectonic keratoplasty using SMILE-extracted lenticule is a comparatively safe, effective, and reliable alternative approach for the treatment of corneal lesions.

A Review on Different Tonometers for Intraocular Pressure Measurement After Photorefractive Keratectomy or Small Incision Lenticule Extraction

This paper aims to review different tonometers for intraocular pressure measurement in eyes after photorefractive keratectomy or small incision lenticule extraction. An Entrez Pubmed search was performed on July 19th, 2020. There were 32 eligible articles investigated in the use of tonometers or biomechanical properties of cornea in post photorefractive keratectomy eyes and 11 articles investigated in post small incision lenticule extraction eyes. Corvis ST and dynamic contour tonometry were found to be accurate for intraocular pressure measurement in post photorefractive keratectomy eyes. For post small incision lenticule extraction eyes, Corvis ST was found to be more accurate than other tonometers. Other tonometers such as Goldmann applanation tonometer, noncontact tonometry, Tonopen, ocular response analyzer can also be used in post photorefractive keratectomy or small incision lenticule extraction eyes in clinical practice; however, it is important for ophthalmologists to take note of the chances of discrepancies.

A porous collagen-based hydrogel and implantation method for corneal stromal regeneration and sustained local drug delivery

Biomaterials designed to replace the diseased cornea could be used to treat corneal blindness where human donor tissue is in short supply, but challenges are the integration of biomaterials with host tissue and cells, avoiding a rapid material degradation and maintaining corneal transparency. Additionally, implantation surgery often triggers an aggressive wound healing response that can lead to corneal thinning and opacity. Here, we report a collagen-based hydrogel with transparency and mechanical properties suitable for replacing a substantial portion of a damaged or diseased corneal stroma. The porous hydrogel permitted migration and population by host cells while maintaining transparency and thickness six months after surgical implantation in an in vivo model of human corneal surgery. With a novel hybrid surgical implantation technique inspired by LASIK refractive surgery, rapid wound healing occurred around implants to maintain biomaterial integrity, transparency and function. Host stromal cell repopulation and regeneration of host epithelium and nerves were observed, as necessary steps towards corneal regeneration. Finally, as a proof-of-principle, the hydrogel loaded with a neuroregenerative drug achieved sustained slow-release drug delivery in vitro. The proposed hydrogel and novel implantation technique together represent a therapeutic approach with translational potential for replacing and regenerating diseased corneal stromal tissue.

Surgical alternatives to keratoplasty in microbial keratitis

Penetrating keratoplasty is often required in microbial keratitis not responding to the standard treatments available or the development of complications like corneal perforation. Performing keratoplasty in microbial keratitis has several challenges, the major ones being the availability of donor corneal tissue and the poor success of the corneal graft performed in such a setting. For overcoming these challenges, several alternatives to keratoplasty have been described. Broadly, these options could be categorized into autologous tissues such as conjunctival and tenon tissue, synthetic products like tissue adhesives and therapeutic contact lenses, or biological tissues like amniotic membrane graft. These alternative modalities are not universal. They have their specific indications in microbial keratitis. Most of these alternatives are useful only for small corneal perforations. While autologous tissues are cost-effective and readily available, lack of tectonic support is a significant limitation. Tissue adhesives are excellent alternatives in terms of tectonic support, but surface irregularity and tissue reaction are their potential limitations. The amniotic membrane is useful for small corneal perforations, but availability, cost, and poor tectonic support restrict its use. Herein, we discuss these various alternatives to keratoplasty in microbial keratitis, their indications, advantages, disadvantages, and the various techniques of performing these procedures.

Application of the SMILE-derived lenticule in therapeutic keratoplasty

PURPOSE

To observe the clinical efficacy of the small incision lenticule extraction (SMILE)-derived lenticule patch graft in therapeutic keratoplasty, especially for the treatment of corneal microperforation or partial-thickness corneal defects.

METHODS

Corneal lenticule obtained from SMILE surgery with diameter greater than 6.5 mm and thickness greater than 100 μm was preserved in a balanced salt solution (Alcon Laboratories, Fort Worth, TX) containing 50 mg/mL penicillin, 50 mg/mL streptomycin, 100 mg/mL neomycin, and 2.5 mg/mL amphotericin for at least 3 months. Preoperatively, anterior segment optical coherence tomography was used to assess the depth of the ulcer and to decide the thickness of the lenticule. Patients were followed up on day 1 and then at 1, 3, and 6 months postoperatively.

RESULTS

Corneal perforation or defects were successfully patched in all 17 eyes; 8 eyes (47%) exhibited improvement postoperative corrected distance visual acuity. During the follow-up period of 6 months, there was no evidence of infection, relapse, or perforation detected in all eyes. Lenticule grafts were attached by graft beds very well and remain clear through to the last follow-up checkup in all eyes treated.

CONCLUSIONS

The lenticule patch graft seems to serve as a safe, feasible, and inexpensive surgical option for the treatment of keratohelcosis or partial-thickness corneal defects, especially in small perforation and defects. There are hopeful signs that SMILE-derived lenticule becomes a potential graft for therapeutic keratoplasty.

Surgical treatment of corneal dermoid by using intrastromal lenticule obtained from small-incision lenticule extraction

PURPOSE

To report a novel technique to treat superficial limbal dermoid by using the corneal intrastromal lenticules obtained from SMILE and to evaluate the initial clinical outcomes of lenticule patch graft for treatment of limbal dermoid.

METHODS

In this single-center case series, lenticules were obtained from patients undergoing SMILE for the correction of myopia and the lenticule patch graft was performed in three patients with limbal dermoid. Patients were postoperatively followed at first, second weeks and first, third months after surgery. The main measured outcome parameters were included the best-corrected visual acuity, transparency of graft, tectonic integrity and restoration of optical transparency.

RESULTS

All surgeries were successful, and all patients recovered well. Obviously, improving tendency in visual acuity and astigmatism was seen at the final follow-up in all eyes. No statistically significant difference has found in the thickness of the cornea between the surgical field and the corresponding normal field. Globe integrity was achieved in all cases, and no immune rejection or perforation was detected until the last follow-up visit in all eyes treated.

CONCLUSIONS

Lenticule keratoplasty may be a safe, feasible and inexpensive surgical option for the treatment of corneal dermoid. It retains globe integrity and decreases the risk of complications such as postoperative limbal ectasia and visible corneal scarring and should be widely promoted in the areas with shortage of donor corneas.

Corneal Stromal Regeneration: Current Status and Future Therapeutic Potential

The corneal stroma comprises 90% of the corneal thickness and is critical for the cornea's transparency and refractive function necessary for vision. When the corneal stroma is altered by disease, injury, or scarring, however, an irreversible loss of transparency can occur. Corneal stromal pathology is the cause of millions of cases of blindness globally, and although corneal transplantation is the standard therapy, a severe global deficit of donor corneal tissue and eye banking infrastructure exists, and is unable to meet the overwhelming need. An alternative approach is to harness the endogenous regenerative ability of the corneal stroma, which exhibits self-renewal of the collagenous extracellular matrix under appropriate conditions. To mimic endogenous stromal regeneration, however, is a challenge. Unlike the corneal epithelium and endothelium, the corneal stroma is an exquisitely organized extracellular matrix containing stromal cells, proteoglycans and corneal nerves that is difficult to recapitulate in vitro. Nevertheless, much progress has recently been made in developing stromal equivalents, and in this review the most recent approaches to stromal regeneration therapy are described and discussed. Novel approaches for stromal regeneration include human or animal corneal and/or non-corneal tissue that is acellular or is decellularized and/or re-cellularized, acellular bioengineered stromal scaffolds, tissue adhesives, 3D bioprinting and stromal stem cell therapy. This review highlights the techniques and advances that have achieved first clinical use or are close to translation for eventual therapeutic application in repairing and regenerating the corneal stroma, while the potential of these novel therapies for achieving effective stromal regeneration is discussed.

Fibrin Glue-Assisted Closure of Macroperforation in Predescemetic Deep Anterior Lamellar Keratoplasty With a Donor Obtained From Small Incision Lenticule Extraction

PURPOSE

To report a case with multiple macroperforations and a double anterior chamber (AC) after predescemetic deep anterior lamellar keratoplasty.

METHODS

A patient was referred after undergoing complicated excision of pseudopterygium that extended onto the cornea. At presentation, an eccentric lamellar patch graft extending over the pupillary axis with a double AC was seen. Surgical intervention showed a predescemetic plane of dissection with 2 macroperforations and iris plugging of the peripheral perforations. Suturing and fibrin glue alone did not seal the macroperforation, and a donor lenticule from small incision lenticule extraction (SMILE) was used to close the larger perforation using fibrin glue. A trephine was then used to mark a larger area of predescemetic dissection that included the original patch graft. A donor corneal graft was sutured after stripping Descemet membrane (DM).

RESULTS

Postoperatively, the double AC resolved, and vision improved to 0.50 decimal equivalent (20/40) by 3 weeks. At 18-month postoperative follow-up, corrected distance visual acuity (CDVA) was 0.67 (20/30). The donor graft remained clear, and the SMILE lenticule with underlying sutures could be visualized.

CONCLUSIONS

A donor lenticule from SMILE surgery is a useful adjunct to seal macroperforations in deep anterior lamellar keratoplasty because the thin uniform lamellar tissue is easily applied using fibrin glue and gives uniform and good apposition on both host and donor sides. It can be used immediately without further preparation unlike hand-fashioned patch grafts.

Differentiation of human embryonic stem cells derived mesenchymal stem cells into corneal epithelial cells after being seeded on decellularized SMILE-derived lenticules

AIM

To evaluate the feasibility of mesenchymal stem cells (MSCs) to differentiate into corneal epithelial cells after being seeded on the decellularized small incision lenticule extraction (SMILE)-derived lenticules.

METHODS

The fresh lenticules procured from patients undergoing SMILE for the correction of myopia were decellularized. The MSCs were subsequently cultivated on those denuded lenticules. The MSCs without lenticules were used as a control. The proliferation activity of the MSCs after seeding 24h was quantitatively determined with the Cell Counting Kit-8 (CCK-8) assay. Immunofluorescence staining and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to assess the marker expression in differentiated MSCs.

RESULTS

The data showed that both fresh and decellularized lenticules could significantly promote the proliferation of MSCs, compared to that in control (P=0.02 for fresh lenticules, P=0.001 for decellularize ones, respectively). The MSCs seeded on both lenticules were positive for cytokeratin 3 (CK3) staining. The expression of CK3 increased 5-fold in MSCs seeded on fresh lenticules and 18-fold on decellularized ones, compared to that in control. There was a significant difference in the expression of CK3 in MSCs seeded on fresh and decellularized lenticules (P<0.001). The expression of CK8 and CK18 was similar in pure MSCs and MSCs seeded on fresh lenticules (P>0.05), while the expression of these markers was decreased in MSCs seeded on decellularized ones.

CONCLUSION

These results suggest that the decellularized lenticules might be more suitable for MSCs to differentiate into corneal epithelial cells, which offers the prospect of a novel therapeutic modality of SMILE-derived lenticules in regenerative corneal engineering.

Tectonic keratoplasty using femtosecond laser lenticule in pediatric patients with corneal perforation secondary to blepharokeratoconjunctivitis: a case report and literature review

Blepharokeratoconjunctivitis secondary to ocular demodicosis in the pediatric population is often neglected and may result in a serious sight-threatening condition. In severe cases, it can lead to corneal perforation necessitating urgent corneal transplantation. However, the shortage and high cost of donor corneas is the foremost limitation of keratoplasty in developing countries. Small-incision lenticule extraction is an advanced flapless femtosecond laser refractive procedure in which an intrastromal corneal lenticule is detached and removed to correct myopia and myopic astigmatism. We herein describe a technique in which lenticules are used for the management of corneal perforation secondary to Demodex-induced blepharokeratoconjunctivitis. The lenticule was sutured over the site of the perforated cornea using 10-0 interrupted nylon sutures. The globe integrity was maintained with a good visual outcome. Thus, tectonic keratoplasty using small-incision lenticule extraction appears to be a safe, cost-effective, and reliable alternative method for the management of corneal perforation secondary to blepharokeratoconjunctivitis.

Corneal remodelling and topography following biological inlay implantation with combined crosslinking in a rabbit model

Implantation of biological corneal inlays, derived from small incision lenticule extraction, may be a feasible method for surgical management of refractive and corneal diseases. However, the refractive outcome is dependent on stromal remodelling of both the inlay and recipient stroma. This study aimed to investigate the refractive changes and tissue responses following implantation of 2.5-mm biological inlays with or without corneal collagen crosslinking (CXL) in a rabbit model. Prior to implantation, rotational rheometry demonstrated an almost two-fold increase in corneal stiffness after CXL. After implantation, haze gradually subsided in the CXL-treated inlays (p = 0.001), whereas the untreated inlays preserved their clarity (p = 0.75). In-vivo confocal microscopy revealed reduced keratocyte cell count at the interface of the CXL inlays at week 8. Following initial steepening, regression was observed in anterior mean curvature from week 1 to 12, being most prominent for the non-CXL subgroups (non-CXL: -12.3 ± 2.6D vs CXL: -2.3 ± 4.4D at 90 μm depth, p = 0.03; non-CXL: -12.4 ± 8.0D vs CXL: -5.0 ± 4.0D at 120 μm depth, p = 0.22). Immunohistochemical analysis revealed comparable tissue responses in CXL and untreated subgroups. Our findings suggest that CXL of biological inlays may reduce the time before refractive stabilization, but longer postoperative steroid treatment is necessary in order to reduce postoperative haze.

Thirty-month results after the treatment of post-LASIK ectasia with allogenic lenticule addition and corneal cross-linking: a case report

Background

To report a first case of lenticule addition and corneal cross-linking for post-LASIK ectasia with associated corneal thinning.

Case presentation

Lenticule addition followed by corneal cross-linking was performed on the left eye of a patient with post-LASIK ectasia. Postoperatively, the corneal power and elevation were stable with a remarkable improvement in corneal thickness, and the lenticule had merged with the adjacent corneal stroma at 30 months follow-up. The patient’s corrected distance visual acuity gained two lines.

Conclusions

This case provides a potential treatment option for patients with keratectasia and keratoconus in association with thin corneal thickness (less than 400 μm) and may provide the benefit of delaying or avoiding the need for keratoplasty, which has its own associated complications and is limited by the availability of donor corneas.

A novel case using femtosecond laser-acquired lenticule for recurrent pterygium: case report and literature review

Small incision lenticule extraction (SMILE) is a minimally invasive, safe and flapless femtosecond laser technique used mainly to correct myopia through extraction of a corneal lenticule. Lenticules obtained in this way are transparent and of high quality, and thus, can be used to treat other corneal diseases. A 65-year-old male patient presented with recurrent pterygium complicated by thin cornea. The patient was treated surgically using a SMILE-extracted lenticule to avoid further complications and to maintain eyeball integrity. The lenticule was sutured over the thin section of cornea using 10-0 interrupted nylon sutures and enclosed by a single layer of amniotic membrane. The patient was evaluated using slit-lamp biomicroscopy and anterior-segment optical-coherence tomography. During an 8-month follow-up, the graft remained intact with no sign of rejection and corneal thickness was maintained. Tectonic keratoplasty using a SMILE-extracted lenticule appears to be a safe, cost-effective and reliable method for treating thin cornea due to repeated surgeries for recurrent pterygium. This is the first case of recurrent pterygium complicated by thin cornea managed surgically using a SMILE-extracted lenticule.

Femtosecond Laser-Assisted Small Incision Endokeratophakia Using a Xenogeneic Lenticule in Rhesus Monkeys

PURPOSE

To evaluate the feasibility and safety of xenogeneic endokeratophakia in rhesus monkeys and to explore the effects of a concave lenticule on refractive power.

METHODS

Three adult New Zealand white rabbits and 6 healthy rhesus monkeys were used. The xenogenic concave grafts were created from the rabbits using a modified small incision lenticule extraction technique; after being cryopreserved in glycerol for 1 week, the grafts were implanted into the monkey recipient corneas. Spherical equivalent (SE), central corneal thickness, and keratometry curvature were assessed preoperatively, 1 week, 1, 4 and 6 months postoperatively. The quality of the xenogenic graft was also assessed by slit-lamp microscopy, in vivo confocal microscopy, and optical coherence tomography with anterior segment imaging.

RESULTS

The graft appeared to be swollen a day after the operation but reduced considerably after a week. A trend of a lower refractive power (hyperopic shift) was demonstrated in relation to the SE after concave graft implantation. The mean SE increased from -0.60 ± 1.31 (median -0.69, interquartile range -1.00 to 0.50) preoperatively to 0.75 ± 1.27 (median 1.38, interquartile range -0.25 to 1.63) at 1 month postoperatively (P = 0.01). Central corneal thickness was significantly thicker each time after surgery compared with that recorded preoperatively (P < 0.01). The anterior and posterior interface between the graft and stroma was visible during the study. Corneal nerve regeneration was evident at 6 months postoperatively. The xenogeneic concave graft was stable and transparent at follow-up. Severe adverse events or evidence of a rejection response were not observed.

CONCLUSIONS

Femtosecond laser-assisted small incision endokeratophakia using a xenogeneic corneal lenticule seems to be feasible and safe, which may provide a new method for myopia correction and keratoconus treatment.

Two-Year Outcome of a Patient Treated With Phototherapeutic Keratectomy and Autologous SMILE Lenticule Transplantation for Flap-Related Complications Following LASIK

PURPOSE

To describe a patient with flap complications after LASIK who was subsequently treated using phototherapeutic keratectomy (PTK) and an autologous lenticule transplant obtained via small incision lenticule extraction (SMILE).

METHODS

A 23-year-old man experienced free flap and partial flap loss in the left eye following LASIK, resulting in corneal stroma opacity 1 month later. The manifest refraction was -3.25 diopters sphere (DS)/-0.50 diopters cylinder (DC) × 100° in the right eye and +2.50 DS/-1.25 DC × 155° in the left eye. His left eye was treated with PTK and transplantation of an autologous lenticule obtained from his right eye using the SMILE procedure.

RESULTS

At the 2-year follow-up visit, the uncorrected distance visual acuity of the left eye had improved from 20/100 to 20/22 and the corrected distance visual acuity had improved from 20/25 to 20/18. Central corneal thickness had increased from 464 to 499 µm. The mean keratometry value had decreased from 45.00 diopters (D) at the 1-month follow-up visit to 39.40 D at the 2-year follow-up visit. Optical coherence tomography examination revealed that the lenticule remained transparent and exhibited a visible demarcation line.

CONCLUSIONS

The transplantation of an autologous lenticule obtained via SMILE combined with PTK improved uncorrected and corrected acuity in this patient with flap loss after LASIK. [J Refract Surg. 2018;34(4):281-285.].

Stromal lenticule transplantation for management of corneal perforations; one year results

PURPOSE

To study application of stromal lenticules extracted by femtolaser small incision lenticule extraction (SMILE) surgery as a surgical adjuvant to seal corneal perforations.

METHODS

Corneal stromal lenticules obtained through SMILE surgery with central thickness 100 μm or more were fixed over corneal perforation sites using 10-0 nylon interrupted stitches with an overlying single layer of amniotic membrane. Seven patients who had been followed up for a minimum of 12 months were assessed using slit-lamp biomicroscopy, fluorescein stain, tonometry, and best spectacle-corrected visual acuity (BSCVA) measurements. Postoperative complications were recorded throughout the follow up period.

RESULTS

Corneal perforations had successfully been sealed in all 7 patients; 3 patients (42.9%) exhibited improved postoperative BSCVA. During the follow-up period of one year, no signs of re-perforation or infections were detected in any patient.

CONCLUSIONS

These early findings suggest that the use of corneal stromal lenticules could be a safe and efficient surgical adjuvant for corneal perforation closure with potential clinical application, together with amniotic membrane, as relatively simple and low cost temporary measures to prepare perforated corneas for further definitive procedures.

A Novel Tectonic Keratoplasty with Femtosecond Laser Intrastromal Lenticule for Corneal Ulcer and Perforation

BACKGROUND

Small incision refractive lenticule extraction (SMILE) is an effective laser procedure that treats myopia. This research was to describe a novel approach to treat corneal ulcer or perforation using the corneal lenticules obtained from SMILE and to evaluate the safety and effectiveness of tectonic keratoplasty with femtosecond laser intrastromal lenticule (TEKIL).

METHODS

A total of twenty patients (22 eyes) were monitored for at least 6 months and were assessed using slit lamp microscopy, optical coherence tomography, and best-corrected visual acuity (BCVA). Postoperative complications throughout the study period were recorded.

RESULTS

Corneal ulcer in 14 patients (16 eyes) and corneal perforation in six patients (6 eyes) were treated with TEKIL. The patients were ten females and ten males, with a mean age of 58.5 ± 16.3 years (range: 16-81 years). In this study, the most causes of corneal ulcer or perforation were immunologic causes (54.5%). After TEKIL procedure, global integrity was achieved in all cases. No immune rejection or perforation was detected. The mean BCVA improved from 0.17 ± 0.20 preoperatively to 0.27 ± 0.25 postoperatively at the final follow-up (t = 2.095, P = 0.052). The postoperative BCVA improved in 12 eyes (54.5%) and maintained in nine eyes (40.9%). Vision function successfully maintained in all eyes (100%). In three cases, corneal ulcers were treated by reoperation of TEKIL at 3 months after the initial surgery for the reason that the residual corneal thickness was <250 μm.

CONCLUSIONS

TEKIL seems to be an effective treatment for corneal ulcer and perforation in the condition of emergency and donor shortage.

Construction of a Corneal Stromal Equivalent with SMILE-Derived Lenticules and Fibrin Glue

The scarcity of corneal tissue to treat deep corneal defects and corneal perforations remains a challenge. Currently, small incision lenticule extraction (SMILE)-derived lenticules appear to be a promising alternative for the treatment of these conditions. However, the thickness and toughness of a single piece of lenticule are limited. To overcome these limitations, we constructed a corneal stromal equivalent with SMILE-derived lenticules and fibrin glue. In vitro cell culture revealed that the corneal stromal equivalent could provide a suitable scaffold for the survival and proliferation of corneal epithelial cells, which formed a continuous pluristratified epithelium with the expression of characteristic markers. Finally, anterior lamellar keratoplasty in rabbits demonstrated that the corneal stromal equivalent with decellularized lenticules and fibrin glue could repair the anterior region of the stroma, leading to re-epithelialization and recovery of both transparency and ultrastructural organization. Corneal neovascularization, graft degradation, and corneal rejection were not observed within 3 months. Taken together, the corneal stromal equivalent with SMILE-derived lenticules and fibrin glue appears to be a safe and effective alternative for the repair of damage to the anterior cornea, which may provide new avenues in the treatment of deep corneal defects or corneal perforations.

Surgical management of corneal infections

PURPOSE OF REVIEW

The purpose of this review is to discuss the options for, and recent developments in, the surgical treatment of corneal infections. Although the mainstay of treatment of corneal infections is topical antimicrobial agents, surgical intervention may be necessary in a number of cases. These include advanced disease at presentation, resistant infections, and progressive ulceration despite appropriate treatment. Prompt and appropriate treatment can make the difference between a good outcome and loss of vision or the eye.

RECENT FINDINGS

There are a number of surgical therapies available for corneal infections. Preferred therapeutic modalities differ based on the size, causation, and location of the infection but consist of either replacement of the infected tissue or structural support of the tissue to allow healing. Although there are no completely novel therapies that have been developed recently, there have been incremental improvements in the existing treatment modalities making them more effective, easier, and safer.

SUMMARY

Several options are available for surgically managing corneal infections. Ophthalmologists should select the optimal procedure based on the individual patient's situation.

VIDEO ABSTRACT

http://links.lww.com/COOP/A20.