Open Ophthalmology Journal最新文献

Aims: To describe a new technique in Descemet Stripping Automated Endothelial Keratoplasty (DSAEK).

Materials and methods: In this technique, we use easily available materials (mainly a Nelaton tube) to make an injector for loading DSAEK lenticule and also easily pulling it (using a gauge 23 needle) into the eye. In this paper, we report outcomes of this technique in four cases.

Results: Using these available instruments could easily lead to a clear postoperative cornea. Mean Endothelial Cell Density (ECD) loss at sixth postoperative month was 26%.

Conclusion: We proposed a novel effective user-friendly and affordable technique to perform DSAEK.

Purpose: To develop in vitro methods to assess binding by sodium hyaluronate in eye drops to corneal surfaces.

Methods: Two different, complementary corneal binding set-ups were developed. In a dynamic in vitro model, confluent corneal epithelial cells (HCE-T) were assembled in chamber slides and a declining channel. A static model was constructed with ex vivo porcine corneas clamped in Franz cells. To test the predictive capacity of models, four different eye drops containing sodium hyaluronate were spiked with tritium-labeled sodium hyaluronate to standardize quantification. In both settings, eye drops were applied for 5 min and physiological conditions were mimicked by flushing with artificial tear fluid. Spreading experiments on HCE-T next to synthetic membranes were used for further characterization.

Results: Binding was more pronounced in dynamic HCE-T model. Three of the four eye drops demonstrated sigmoidal elution of sodium hyaluronate, suggesting pronounced binding. One solution eluted distinctly faster, likewise the buffer control. The static method produced a similar ranking but at lower levels. When eye drops in which phosphate buffer was replaced by citrate buffer (i.e., to prevent calcification) were used, binding was not influenced. All eye drops spread immediately when placed on HCE-T and at the same order of magnitude on glass and polyethylene terephthalate surfaces.

Conclusion: Dynamic and static models performed on different corneal sources were used to determine sodium hyaluronate binding kinetics in solutions under physiological conditions. These methodologies resulted in a ranking of the capacity of sodium hyaluronate to bind in vitro to corneal surfaces.

Worldwide, femtosecond Laser Assisted In-situ Keratomileusis (LASIK) is a well known and commonly used refractive technique, although Small Incision Lenticule Extraction (SMILE) has become increasingly popular since it was introduced in 2011. In LASIK, a corneal flap is cut with a microkeratome or femtosecond laser, followed by thinning of the stromal bed with excimer laser ablation. In SMILE, a minor intrastromal lenticule is cut with a femtosecond laser and subsequently removed through a small incision, leaving the anterior and strongest part of the cornea almost intact. Both LASIK and SMILE require cutting of corneal lamellae that may reduce the biomechanical stability of the cornea, with the potential risk of corneal iatrogenic ectasia as a severe complication. However, SMILE preserves the anterior corneal integrity and may, in theory, better preserve the corneal biomechanical strength than LASIK after surgery. A review aimed to examine the current literature that describes and compares the corneal biomechanical properties after Laser Assisted In-situ Keratomileusis (LASIK) and Small Incision Lenticule Extraction (SMILE). A comprehensive search was performed in Pubmed.gov using the following search queries: Corneal biomechanical properties, corneal biomechanics, ocular response analyser, ocular response analyzer, ORA, ex vivo, in vitro, Corvis, Corvis ST, LASIK, and SMILE.

Background: Descemet Membrane Endothelial Keratoplasty (DMEK) is now becoming the popular form of endothelial keratoplasty using only donor DM with healthy endothelium as true component lamellar corneal surgery.

Objective: To analyze the results of visual outcomes, endothelial cell loss and complications of Descemet membrane endothelial keratoplasty in first consecutive 100 Indian eyes.

Methods: 100 eyes of 95 consecutive patients with endothelial dysfunctions of different etiologies scheduled for DMEK, were included in this study. In each case, surgeon prepared tissue using McCarey Kaufman medium- or Cornisol-preserved donor cornea with a cell count of ≥2500 cells/mm². Surgical complications, Best Spectacle Corrected Visual Acuity (BSCVA); Endothelial Cell Density (ECD) and Endothelial Cell Loss (ECL) were analyzed for each patient after a minimum follow-up of three months.

Results: The Main indication was pseudophakic corneal edema or bullous keratopathy in 52 (52%) eyes. 38 (38%) eyes had Fuchs' dystrophy with various grades of cataract. In 43 phakic eyes, DMEK was combined with cataract surgery and intraocular lens implantation. Mean DM-roll preparation time was 7.5 ± 2.8 min and in 3 eyes, DM-graft were damaged. After 3-months, BSCVA was ≥20/25 in 57 (57.6%) cases. Mean ECD was 2123 ± 438/mm² (range: 976 - 3208/ mm²) and the mean endothelial cell loss after 3-months was 26.92 ± 13.40 (range: 4.90 - 66.6%). Partial DM detachment occurred in 8 (8.0%) eyes and rebubbling required in 4 eyes. Iatrogenic primary graft failure occurred in one eye.

Conclusion: Descemet membrane endothelial keratoplasty is a safe and effective procedure in several types of endothelial diseases among Indian patients with encouraging surgical and visual outcomes. Complications are less and endothelial cell loss percentage is acceptable.

Background: LASIK Xtra is a recently described technique which combines LASIK and accelerated corneal cross-linking(CXL) in the same setting. Its long-term outcome in Asians with high myopia is not well described.

Objectives: To compare the efficacy, predictability and safety of LASIK Xtra with LASIK in patients with high myopia.

Method: This is a retrospective study comparing 50 consecutive eyes undergoing LASIK Xtra for the correction of high myopia and/or myopic astigmatism (-6.63 to -15.50 D manifest spherical equivalent) with a matched control group of 50 eyes undergoing LASIK alone for correction of high myopia (-6.00 to -12.25 D manifest spherical equivalent). Mean follow-up was 5.7 months (range, 1.5-13.3 months) for LASIK Xtra and 3.6 months (range, 1.7-4.2 months) for LASIK only. Outcome measures included Uncorrected Distance Visual Acuity (UDVA), Corrected Distance Visual Acuity (CDVA), refraction and intraoperative and postoperative complications.

Results: At post-operative 3 months, all eyes achieved UDVA of 20/40 or better, and 80.0% of LASIK Xtra eyes achieved UDVA of 20/20 or better, compared to 66.0% of LASIK only eyes (p = 0.115). Efficacy indices were 0.99±0.17 for LASIK Xtra and 0.94±0.17 for LASIK only (p = 0.164). The proportion of eyes within ±0.50 D of attempted correction was 84% in the LASIK only group and 72% in the LASIK Xtra group at post-operative 3 months (p = 0.148). Safety indices were 1.11±0.19 and 1.11±0.18 in the LASIK Xtra and LASIK only groups, respectively (p = 0.735).

Conclusion: LASIK Xtra achieved comparable safety, predictability and efficacy as LASIK in patients with high myopia. Good refractive stability was attained at 6-12 months. Further long term studies are required to determine whether simultaneous CXL is able to reduce postoperative LASIK keratectasia in high-risk individuals.

Aim: To evaluate the predictive factors of LASIK procedure for high myopia with or without astigmatism using a combination of high-frequency femtosecond-assisted LASIK followed by an excimer laser.

Methods: This study was a retrospective interventional case series study to evaluate myopic eyes undergoing high platform LASIK with FEMTO LDV Z2 intervention, followed by WaveLight®EX500 excimer laser machine. Subjects were divided into 2 groups: high myopia (SE of -6.01 to -9.00 D) and very high myopia (SE of -9.01 D or higher). Myopic eyes (Spherical Equivalent/SE) less than -13 D were included in this study. Visual Acuity (VA) was evaluated 1 day and 60 days after the procedure. Predictive factors, such as age, degree of sphere, degree of astigmatism, keratometric reading and axial length were analyzed to detect any influences affecting the final VA results.

Results: A total of 316 myopia eyes underwent intervention, mean age: 25.3±3.8 years. Target treatment was achieved in 96.1% of patients with high myopia and 69.9% of patients with very high myopia. High degree of sphere and astigmatism constitutes an important factor influencing final VA.

Conclusion: Modern machines provide a more promising efficacy and success of LASIK procedure in high myopia: important predictive factors were a high degree of sphere and astigmatism for achieving the optimal final outcome.

Background: Fuchs Endothelial Corneal Dystrophy (FECD) is a progressive disease that affects the corneal endothelium in both eyes. Recent studies have identified a novel genetic basis for FECD, and basic research findings have provided evidence for its underlying pathophysiology. Since its first description by Ernst Fuchs in 1910, the only therapeutic choice has been corneal transplantation using donor corneas. However, accumulating evidence suggests that a change in this "rule" may be imminent.

Conclusions: This article reviews the current knowledge of the genetics and pathophysiology of FECD, and it introduces some potent therapeutic modalities that show promise as new treatments for this disorder.

Purpose: To assess the advantages offered by the air pump assisted PDEK technique that utilizes pressurized Anterior Chamber (AC) air infusion.

Methods: Pressurized air infusion was provided through an anterior chamber maintainer connected to the fluid air exchange system of a posterior vitrectomy machine during surgery.

Results: Pressurized air infusion within the AC helped perform Descemetorhexis, prevented bleeding during Peripheral Iridectomy (PI) and synechiolysis, prevented oozing of blood from peripheral corneal neovascularization into the AC and thus helped maintain a non-fibrinous AC environment. In addition, it helped in precise graft manipulation, centration, edge unfolding and unwrinkling after it was floated against the stroma as well as faster graft adhesion. It also prevented AC depth fluctuations during intra-cameral maneuvers and prevented intra-operative as well as post-operative graft detachment.

Conclusions: This technique makes several steps of surgery easier and improves graft adhesion.

Objective: To review the literature on current applications of corneal Collagen Cross-Linking (CXL).

Methods: A review of publications on corneal cross-linking was conducted. This included systemic reviews, randomized controlled clinical trials, cohort studies, case-controlled studies and case series. A summary of the publications is tabulated.

Results: The original indication of riboflavin - Ultraviolet-A (UVA) induced corneal collagen cross-linking is to arrest the progression of keratoconus. Studies show that it is effective in arresting the progression of keratoconus and post-LASIK ectasia with the standard Dresden protocol (epithelium-off). There are also improvements in visual, keratometric and topographic measurements over time. Severe complications of cross-linking are rare. The epithelium-on techniques have less efficacy than the Dresden protocol. Accelerated protocols have variable results, with some studies reporting comparable outcomes to the Dresden protocol while other studies reporting less efficacious outcomes. Cross-linking combined with refractive procedures provide better visual outcome but long term studies are warranted. Cross-linking for the treatment of infective keratitis is a promising new treatment modality. Initial studies show that it is more effective for superficial rather than deep infections and for bacterial rather than fungal infections.

Conclusions: Corneal cross-linking is a procedure with an expanding list of indications from the treatment of corneal ectasias to infective keratitis. While the standard Dresden protocol is established as the gold standard treatment for progressive keratoconus, the more recent protocols may require further refinements, investigative and long-term studies.