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Journal of Clinical Medicine Jun 2023To examine the 12-month clinical and refractive outcomes of PRK performed with a UV all-solid-state laser.
BACKGROUND
To examine the 12-month clinical and refractive outcomes of PRK performed with a UV all-solid-state laser.
METHODS
The study included healthy patients with myopia and/or compound myopic astigmatism enrolled for refractive surgery and treated with PRK using a 210 nm wavelength, 2 kHz repetition rate, UV all-solid-state laser (LaserSoft, Katana Technologies GmbH, Kleinmachnow, Germany). All subjects were examined at baseline and after 1, 3, 6, and 12 months after the treatment with a slit lamp, refraction, visual acuity assessment (logMAR chart), tonometry, ophthalmoscopy, and corneal tomography with a Scheimpflug camera. The outcome measures considered were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, central corneal thickness, and transparency. The efficacy, safety, predictability, and stability were determined.
RESULTS
The study included 34 eyes of 19 patients. The mean UDVA changed from 1.20 ± 0.43 to -0.05 ± 0.10 logMAR at 12 months, and the mean CDVA changed from -0.03 ± 0.06 to -0.06 ± 0.09 logMAR, respectively. The mean spherical equivalent (SE) changed from -4.90 ± 2.12 D to -0.01 ± 0.40 D and was within ±0.50 D of the intended correction in 91% of eyes and within ±1.00 D in 97% of eyes at 12 months. No eyes lost lines of visual acuity, and 64% of eyes gained one or more lines.
CONCLUSIONS
PRK with the 210 nm wavelength, 2 kHz repetition rate, all-solid-state laser LaserSoft system proved to have good visual, refractive, and clinical outcomes after the follow-up at 12 months. The emerging gas-free, solid-state technology might be considered a valid alternative for the gas operating lasers for corneal refractive surgery.
PubMed: 37445353
DOI: 10.3390/jcm12134311 -
Indian Journal of Ophthalmology Jul 2023In LASIK (laser in situ keratomileusis), a hinged corneal flap is made, which enables the flap to be lifted and the excimer laser to be applied to the stromal bed. If...
BACKGROUND
In LASIK (laser in situ keratomileusis), a hinged corneal flap is made, which enables the flap to be lifted and the excimer laser to be applied to the stromal bed. If the hinge of the corneal flap detaches from the cornea, the flap is called a free cap. A free cap is a rare intra-operative complication of LASIK most commonly associated with the use of a microkeratome on corneas with flat keratometry, which predisposes to a small flap diameter. Free caps are preventable and treatable. Rarely does the complication lead to a severe or permanent decrease in visual acuity.
PURPOSE
As free caps are avoidable, prevention is critical. Our video gives some tips and tricks on how to avoid a free flap and also focuses on how to manage a cut through a free flap.
SYNOPSIS
If a free cap is created, the surgeon must decide whether to continue with excimer laser ablation or to abort the procedure. When to abort: If the stromal bed is irregular, the flap is replaced without applying laser ablation. Without ablation, generally, there is no change in refractive error or significant loss of visual acuity. When to continue: If the stromal bed is regular and the cap is of normal thickness, the surgeon may proceed with ablation. To prevent desiccation, the free cap should be handled with caution and should be placed on a drop of balanced salt solution. The free cap should be placed epithelial facing up, along with a bandage contact lens. The endothelial cell pump mechanism typically allows the cap to re-adhere tightly.
HIGHLIGHTS
Risk factors for a free cap are generally anatomic or mechanical. Especially in flat corneas, an appropriate ring and stop size should be chosen looking at the nomogram on the basis of the keratometry values. Deep orbits and deep-seated eyes should be looked for as PRK is a better option in such cases. Inadequate suction should be dealt with a lot of care, and once this is done, the vacuum should be stopped. Re-docking of the microkeratome with suction can be done again. Prior testing of the microkeratome and a good verbal anesthesia are a few more such important points to be pondered upon. This video gives us such tips and is a comprehensive video for a novice surgeon performing microkeratome LASIK.
VIDEO LINK
https://youtu.be/piU9nK6rbm4.
Topics: Humans; Free Tissue Flaps; Myopia; Cornea; Keratomileusis, Laser In Situ; Photorefractive Keratectomy; Lasers, Excimer; Corneal Stroma
PubMed: 37417158
DOI: 10.4103/IJO.IJO_756_23 -
Middle East African Journal of... 2022The influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurement by Diaton is debatable. We present a correlation of CCT to transpalpebral IOP...
Trans Palpebral Intraocular Pressure Measurement by Diaton Tonometer and Central Corneal Thickness in Eyes before and after Transepithelial Photorefractive Keratectomy of Saudi Patients.
PURPOSE
The influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurement by Diaton is debatable. We present a correlation of CCT to transpalpebral IOP (tpIOP) and its determinants in patients undergoing transepithelial photorefractive keratectomy (TPRK) in Saudi Arabia.
METHODS
In this cross-sectional study held in 2022, the IOP of patients undergoing TPRK was measured by Diaton tonometer. The CCT was measured before and 1 week after refractive surgery. The correlation coefficient of CCT and IOP and its Pearson value were estimated. The effects of gender, type of refractive error (RE), and corneal epithelial thickness (CET) on the correlation of IOP to CCT were reviewed.
RESULTS
We studied 202 eyes in 101 patients (Male: Female, 47:53; age 25.7 ± 5.8 years). The tpIOP was 15.1 ± 2.8 mmHg before, 15.9 ± 2.8 mmHg 1 week after, and 15.7 ± 4.1 mmHg 1 month after TPRK. The CCT was significantly correlated with tpIOP before surgery (Pearson correlation 0.168, = 0.017) and after tPRK (Pearson correlation 0.246, < 0.001). Gender ( = 0.96), CET ( = 0.43), and type of RE ( = 0.99) were not significant determinants of correlation between CCT and tpIOP before TPRK. The correlation of tpIOP and CCT was not affected by gender ( = 0.07), CET ( = 0.39), and type of RE ( = 0.13).
CONCLUSION
CCT should be considered before interpreting tpIOP measured by with Diaton. Diaton could be a useful tool to monitor IOP changes in young patients undergoing refractive surgery.
Topics: Humans; Male; Female; Young Adult; Adult; Photorefractive Keratectomy; Intraocular Pressure; Cornea; Tonometry, Ocular; Cross-Sectional Studies; Saudi Arabia; Refractive Errors
PubMed: 37408723
DOI: 10.4103/meajo.meajo_156_22 -
Turkish Journal of Ophthalmology Jun 2023Isolated from , mitomycin C (MMC) has various applications in the management of corneal and external disease due to its ability to modulate cellular proliferation. It... (Review)
Review
Isolated from , mitomycin C (MMC) has various applications in the management of corneal and external disease due to its ability to modulate cellular proliferation. It has been employed in pterygium surgery, ocular surface neoplasia, and refractive surgery. Currently, there is no definite consensus on the treatment protocols for each of the aforementioned applications. Although its benefits in the management of corneal and external diseases are promising, MMC use has potential complications including endothelial cell loss, corneal perforation, scleral melt, secondary glaucoma, iritis, and endophthalmitis. This article will review the literature regarding the use of MMC in the field of cornea and external disease and describe protocols employed with corresponding outcomes.
Topics: Humans; Mitomycin; Photorefractive Keratectomy; Lasers, Excimer; Cornea
PubMed: 37345314
DOI: 10.4274/tjo.galenos.2023.97932 -
Korean Journal of Ophthalmology : KJO Aug 2023Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant corneal stromal dystrophy that is caused by p.Arg124His mutation of transforming growth factor β...
Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant corneal stromal dystrophy that is caused by p.Arg124His mutation of transforming growth factor β induced (TGFBI) gene. It is characterized by well demarcated granular shaped opacities in central anterior stroma and as the disease progresses, extrusion of the deposits results in ocular pain due to corneal epithelial erosion. Also, diffuse corneal haze which appears late, causes decrease in visual acuity. The prevalence of GCD2 is high in East Asia including Korea. Homozygous patients show a severe phenotype from an early age, and the heterozygote phenotype varies among patients, depending on several types of compound heterozygous TGFBI mutations. In the initial stage, conservative treatments such as artificial tears, antibiotic eye drops, and bandage contact lenses are used to treat corneal erosion. Different surgical methods are used depending on the depth and extent of the stromal deposits. Phototherapeutic keratectomy removes anterior opacities and is advantageous in terms of its applicability and repeatability. For deeper lesions, deep anterior lamellar keratoplasty can be used as the endothelial layer is not always affected. Recurrence following these treatments are reported within a wide range of rates in different studies due to varying definition of recurrence and follow-up period. In patients who have undergone corneal laser vision-correction surgeries such as photorefractive keratectomy, LASEK, or LASIK including SMILE surgery, corneal opacity exacerbates rapidly with severe deterioration of visual acuity. Further investigations on new treatments of GCD2 are necessary.
Topics: Humans; Corneal Dystrophies, Hereditary; Cornea; Photorefractive Keratectomy; Keratomileusis, Laser In Situ; Corneal Opacity; Corneal Ulcer; Transforming Growth Factor beta
PubMed: 37336511
DOI: 10.3341/kjo.2023.0032 -
Journal of Clinical Medicine May 2023Dry eye disease is the most frequent non-refractive postoperative complication following refractive surgery. This prospective study investigated the development of dry...
Dry eye disease is the most frequent non-refractive postoperative complication following refractive surgery. This prospective study investigated the development of dry eye disease after three common refractive laser surgeries: laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and laser-assisted sub-epithelial keratectomy (LASEK). Patients who underwent uneventful refractive surgery in a single private medical center between May 2017 and September 2020 were included. Ocular surface disease was graded according to the Dry Eye Workshop severity (DEWS) classification. Patients were examined 6 months following refractive surgery. The analysis included 251 eyes of 137 patients: 64 eyes (36 patients) after LASEK, 90 eyes (48 patients) after PRK, and 97 eyes (53 patients) after LASIK. At 6 months post-surgery, the DEWS score was higher for the LASIK than the PRK and LASEK groups ( = 0.01). For the total cohort, severe DEWS score (grades 3 and 4) at 6 months post-surgery was correlated with female gender ( = 0.01) and to the amount of refractive correction ( < 0.001), but not to age ( = 0.87). In conclusion, LASIK surgery and female gender were associated with dry eye. Patients, particularly those with high myopia, should be counseled about the risk of developing dry eye after refractive surgeries.
PubMed: 37297956
DOI: 10.3390/jcm12113761 -
Molecular Vision 2023To understand which cell types, either alone or in combination, contribute to the assembly of the epithelial basement membrane (BM) during corneal wound healing.
PURPOSE
To understand which cell types, either alone or in combination, contribute to the assembly of the epithelial basement membrane (BM) during corneal wound healing.
METHODS
A 3D corneal organotypic model and an in situ rabbit photorefractive keratectomy (PRK) model were used in this study. The 3D corneal organotypic model was established by culturing the rabbit corneal epithelial cells with either corneal fibroblasts or myofibroblasts embedded in collagen type I for 18 days. Corneal fibroblasts were isolated from fresh rabbit corneas, and the myofibroblasts were derived either directly from bone marrow or differentiated from corneal fibroblasts. Immunocytochemistry for alpha-smooth muscle actin (SMA), vimentin, desmin, and vinculin markers confirmed well-differentiated myofibroblasts. Immunohistochemistry was performed in cryofixed sections for BM markers, including laminin alpha-5, laminin beta-3, perlecan, nidogen-1, and collagen type IV. Specimens were also examined with transmission electron microscopy (TEM). Corneas were collected from rabbits after -3 diopter (D) PRK at different time points after surgery, with four corneas at each time point in each group. Cryofixed corneal sections were stained for vimentin, alpha-SMA, and nidogen-1.
RESULTS
The formation of an epithelial BM with expression of laminin alpha-5, laminin beta-3, perlecan, nidogen-1, and collagen IV was observed at the interface between the corneal epithelial cells and corneal fibroblasts. TEM images further confirmed the presence of epithelial BM in organotypic cultures of epithelial cells and corneal fibroblasts. No epithelial BM was observed in cultures of corneal epithelial cells and myofibroblasts (cornea or bone marrow derived), corneal epithelial cells alone, or corneal fibroblasts alone. In rabbit corneas after -3D PRK, a strong association was observed between the regenerating epithelial BM and the presence of corneal fibroblasts at the site of epithelial BM generation.
CONCLUSIONS
The corneal epithelial BM assembly is mediated by epithelial cells in coordination with corneal fibroblasts during wound healing.
Topics: Animals; Rabbits; Laminin; Vimentin; Cornea; Fibroblasts; Wound Healing; Photorefractive Keratectomy; Extracellular Matrix Proteins; Epithelial Cells; Basement Membrane; Corneal Stroma
PubMed: 37287640
DOI: No ID Found -
Clinical Ophthalmology (Auckland, N.Z.) 2023Transepithelial photorefractive keratectomy (Trans PRK) is a relatively new technology for refractive surgery and has shown promising results in myopia correction. The... (Review)
Review
Transepithelial photorefractive keratectomy (Trans PRK) is a relatively new technology for refractive surgery and has shown promising results in myopia correction. The data on hyperopia correction by this method are limited. In this review, we have attempted to understand the outcomes of this technology on hyperopic eyes. There are comparable results with conventional PRK and laser in situ keratomileusis (LASIK) as far as refractive stability, regression rate, predictability, and post-operative complications are concerned. The best results have been obtained in lower hyperopic corrections. In moderate to higher hyperopia, the limited data available show higher regression, unstable visual outcomes, and increased stromal haze. There is a need to evaluate the technology further to understand its success for hyperopic refractive surgery.
PubMed: 37273504
DOI: 10.2147/OPTH.S415636 -
Taiwan Journal of Ophthalmology 2023Herpes endotheliitis is a less common manifestation of herpes keratitis, and characteristic examination findings include corneal edema and the presence of keratic...
Herpes endotheliitis is a less common manifestation of herpes keratitis, and characteristic examination findings include corneal edema and the presence of keratic precipitates. Infection may be primary or secondary to herpes virus reactivation following exposure to a potential trigger such as physiologic stress or environmental factors. Ocular surgery, including laser-assisted keratomileusis (LASIK) and photorefractive keratectomy (PRK), can trigger reactivation in patients with or without a documented history of previous herpes infection. We present two patients with visually insignificant stromal scarring who denied a previous history of herpetic disease and developed herpes endotheliitis following LASIK and PRK. We demonstrate the importance of an appropriately thorough preoperative evaluation and further workup of any corneal abnormalities, even if such findings initially appear inconsequential.
PubMed: 37252172
DOI: 10.4103/tjo.TJO-D-22-00156