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Lancet (London, England) May 2019Refractive surgery has evolved beyond laser refractive techniques over the past decade. Laser refractive surgery procedures (such as laser in-situ keratomileusis),... (Review)
Review
Refractive surgery has evolved beyond laser refractive techniques over the past decade. Laser refractive surgery procedures (such as laser in-situ keratomileusis), surface ablation techniques (such as laser epithelial keratomileusis), and photorefractive keratectomy have now been established as fairly safe procedures that produce excellent visual outcomes for patients with low-to-moderate amounts of ametropia. Additionally, a broader selection of options are now available to treat a wider range of refractive errors. Small incision lenticule extraction uses a femtosecond laser to shape a refractive lenticule, which is removed through a small wound. The potential advantages of this procedure include greater tectonic strength and less dry eye. In the future, intracorneal implants could be used to treat hyperopia or presbyopia. Phakic intraocular implants and refractive lens exchange might be useful options in carefully selected patients for correcting high degrees of ametropia. Thus, physicians are now able to provide patients with the appropriate refractive corrective option based on the individual's risk-benefit profile.
Topics: Humans; Keratomileusis, Laser In Situ; Lens Implantation, Intraocular; Photorefractive Keratectomy; Randomized Controlled Trials as Topic; Refractive Surgical Procedures
PubMed: 31106754
DOI: 10.1016/S0140-6736(18)33209-4 -
Indian Journal of Ophthalmology Apr 2023Dry eye disease is the most common complication and a frequent cause of patient dissatisfaction after corneal laser refractive surgery, which includes laser-assisted in... (Review)
Review
Dry eye disease is the most common complication and a frequent cause of patient dissatisfaction after corneal laser refractive surgery, which includes laser-assisted in situ keratomileusis (LASIK), small-incision lenticule extraction (SMILE), and photorefractive keratectomy (PRK). It has a complex, multifactorial etiology and is characterized by a highly variable clinical presentation. A detailed preoperative screening and optimization of the ocular surface prior to refractive surgery are the key to minimizing the incidence and severity of postoperative dry eye. Diagnosis of postrefractive surgery dry eye remains a challenge as no single symptom or clinical parameter is confirmative of the condition, and the symptoms and signs may not correlate well in many cases. A thorough understanding of the pathomechanism of the disease and its manifestations is essential to facilitate a treatment approach that is individualized for each patient. This article reviews various aspects of postrefractive surgery dry eye including its epidemiology, etiopathogenesis, risk factors, diagnosis, and management.
Topics: Humans; Lasers, Excimer; Myopia; Photorefractive Keratectomy; Keratomileusis, Laser In Situ; Dry Eye Syndromes
PubMed: 37026241
DOI: 10.4103/IJO.IJO_3406_22 -
Biology of keratorefractive surgery- PRK, PTK, LASIK, SMILE, inlays and other refractive procedures.Experimental Eye Research Sep 2020The outcomes of refractive surgical procedures to improve uncorrected vision in patients-including photorefractive keratectomy (PRK), laser in-situ keratomileusis... (Review)
Review
The outcomes of refractive surgical procedures to improve uncorrected vision in patients-including photorefractive keratectomy (PRK), laser in-situ keratomileusis (LASIK), Small Incision Lenticule Extraction (SMILE) and corneal inlay procedures-is in large part determined by the corneal wound healing response after surgery. The wound healing response varies depending on the type of surgery, the level of intended correction of refractive error, the post-operative inflammatory response, generation of opacity producing myofibroblasts and likely poorly understood genetic factors. This article details what is known about these specific wound healing responses that include apoptosis of keratocytes and myofibroblasts, mitosis of corneal fibroblasts and myofibroblast precursors, the development of myofibroblasts from keratocyte-derived corneal fibroblasts and bone marrow-derived fibrocytes, deposition of disordered extracellular matrix by corneal fibroblasts and myofibroblasts, healing of the epithelial injury, and regeneration of the epithelial basement membrane. Problems with epithelial and stromal cellular viability and function that are altered by corneal inlays are also discussed. A better understanding of the wound healing response in refractive surgical procedures is likely to lead to better treatments to improve outcomes, limit complications of keratorefractive surgical procedures, and improve the safety and efficiency of refractive surgical procedures.
Topics: Corneal Surgery, Laser; Humans; Keratomileusis, Laser In Situ; Keratoplasty, Penetrating; Lasers, Excimer; Myopia; Photorefractive Keratectomy; Refraction, Ocular
PubMed: 32653492
DOI: 10.1016/j.exer.2020.108136 -
Survey of Ophthalmology 2020Phototherapeutic keratectomy is an excimer laser-based surgical procedure widely performed by corneal surgeons for treating anterior corneal stromal pathologies.... (Review)
Review
Phototherapeutic keratectomy is an excimer laser-based surgical procedure widely performed by corneal surgeons for treating anterior corneal stromal pathologies. Phototherapeutic keratectomy helps by ablating the corneal stroma, thereby improving corneal clarity and smoothening the surface. Transient discomfort and induced hyperopia from corneal flattening are the immediate postoperative concerns. The long-term course is often marked by the recurrence of original corneal pathology and corneal haze formation. Phototherapeutic keratectomy, however, allows for repeat stromal ablation for managing recurrences, as the corneal thickness permits, without affecting the outcome of future keratoplasty. Adjunctive methods such as topical mitomycin-C may be additionally used to reduce recurrence rates. Also, various masking agents such as carboxymethyl cellulose, sodium hyaluronate, and dextran are used in eyes with irregular corneal surface to allow for uniform stromal ablation. Overall, phototherapeutic keratectomy has provided corneal surgeons an additional surgical tool, particularly those residing in developing nations where the availability of donor corneal tissue is an important limiting factor.
Topics: Cornea; Corneal Dystrophies, Hereditary; Humans; Lasers, Excimer; Photorefractive Keratectomy; Treatment Outcome; Visual Acuity
PubMed: 31306672
DOI: 10.1016/j.survophthal.2019.07.002 -
Current Opinion in Ophthalmology Jul 2018To review current concepts regarding the mechanisms of postoperative pain after photorefractive keratectomy (PRK) and review available treatment options. (Review)
Review
PURPOSE OF REVIEW
To review current concepts regarding the mechanisms of postoperative pain after photorefractive keratectomy (PRK) and review available treatment options.
RECENT FINDINGS
Many clinical studies have established the safety and efficacy of different topical and systematic therapeutic agents and techniques for the treatment of postoperative pain after PRK, especially topical nonsteroidal anti inflammatory agents and oral nonsteroidal and narcotic medications. New therapeutic agents and techniques are continuously studied, introducing new agents and comparing teh efficacy of different regimens. Postoperative pain severity varies widely between patients, and no single strategy has been proven best for acute pain management.
SUMMARY
To date, the literature supports the use of topical agents such as nonsteroidal anti-inflammatory medications (NSAIDs) and diluted topical anesthetics in combination with oral agents such as opiates and NSAIDs for acute pain management. The use of local agents and techniques is preferred due to their less significant side effect profile. The use of systemic opiate agents is reserved for breakthrough pain.
Topics: Analgesics, Opioid; Anesthetics, Local; Anti-Inflammatory Agents, Non-Steroidal; Eye Pain; Humans; Myopia; Pain Management; Pain, Postoperative; Photorefractive Keratectomy
PubMed: 29708926
DOI: 10.1097/ICU.0000000000000486 -
Journal of Cataract and Refractive... Oct 2018Transepithelial photorefractive keratectomy (PRK) was introduced to prevent complications from conventional PRK and femtosecond laser-assisted laser in situ... (Review)
Review
Transepithelial photorefractive keratectomy (PRK) was introduced to prevent complications from conventional PRK and femtosecond laser-assisted laser in situ keratomileusis (LASIK). In the 2-step platform, phototherapeutic keratectomy is followed by PRK. It did not show notable safety or efficacy superiorities over conventional PRK. In the conventional single-step transepithelial PRK, ablation of epithelium and stroma occurs in a single continuous session by an Amaris laser. It showed better comparative safety results. Reverse single-step transepithelial PRK and the platform using smart-pulse technology were recent improvements in the single-step Amaris laser. They provide a smoother postablative stromal bed counter. In the refined single-step platform, a modified nomogram is used for determination of ablation parameters, along with modifications in postablative measures. It yielded better comparative results in hyperopia. Controlled trials comparing reverse, smart-pulse technology-equipped, or refined platforms of single-step transepithelial PRK with other modern laser-assisted methods could provide more robust evidence on the topic. Some key elements with significant roles in post-transepithelial PRK outcomes are discussed.
Topics: Cornea; Epithelium, Corneal; Humans; Hyperopia; Lasers, Excimer; Myopia; Photorefractive Keratectomy; Treatment Outcome; Visual Acuity
PubMed: 30172569
DOI: 10.1016/j.jcrs.2018.07.021 -
Journal Francais D'ophtalmologie Nov 2021Corneal haze represents subepithelial corneal fibrosis, a manifestation of a pathological healing process. It occurs as a result of an epithelial-stromal lesion... (Review)
Review
Corneal haze represents subepithelial corneal fibrosis, a manifestation of a pathological healing process. It occurs as a result of an epithelial-stromal lesion involving a break in the epithelial barrier. It is an inflammatory response that involves the migration, multiplication and differentiation of keratocytes into mature myofibroblasts, causing loss of corneal transparency. Although it is a transient phenomenon, this complication is feared following refractive photokeratectomy (PRK), because it can cause alterations in the quality of vision, refractive regression and decreased visual acuity. The severity of these symptoms is correlated with the severity of the corneal haze, which can be assessed clinically or by objective means such as corneal densitometry measurement. The frequency and severity of corneal haze increase with the depth of photoablation in PRK and are therefore increased during the treatment of severe ametropia. Considering that no consensus exists, the application of mitomycin C (MMC) intraoperatively and topical corticosteroids postoperatively are conventionally used to inhibit collagen synthesis, sometimes in combination with various protocols depending on the center or surgeon. This review of the literature reports the current knowledge on corneal haze, in order to better understand it and optimise its prevention in the context of a decreased MMC supply, which has occurred in the past and could recur in the future.
Topics: Cornea; Corneal Opacity; Humans; Lasers, Excimer; Mitomycin; Photorefractive Keratectomy
PubMed: 34538661
DOI: 10.1016/j.jfo.2021.05.006 -
Cornea Oct 2023Customized photorefractive keratectomy with minimal tissue ablation combined with corneal cross-linking seems to be a long-term safe and effective strategy for...
Customized photorefractive keratectomy with minimal tissue ablation combined with corneal cross-linking seems to be a long-term safe and effective strategy for anatomical and visual management of keratoconus, postsurgical ectasia, and other ectasia management. Multiple published studies, many with long-term follow-up, have supported the Athens Protocol and its various forms as a means to manage corneal ectatic disorders, which not only stabilize corneal shapes but also improve functional vision.
Topics: Humans; Keratoconus; Photorefractive Keratectomy; Corneal Cross-Linking; Dilatation, Pathologic
PubMed: 37669421
DOI: 10.1097/ICO.0000000000003320 -
Current Opinion in Ophthalmology Jul 2021Corneal nerve function is an important consideration for the refractive surgeon. In patients without a history of neuropathy, refractive surgery can lead to destruction... (Review)
Review
PURPOSE OF REVIEW
Corneal nerve function is an important consideration for the refractive surgeon. In patients without a history of neuropathy, refractive surgery can lead to destruction of corneal nerves and may predispose to keratopathy. The purpose of this review is to provide an update on the effect of refractive surgery on corneal nerve function and the potential for an increased risk of neurotrophic keratopathy development.
RECENT FINDINGS
Recent studies have reinforced that refractive surgery can cause anatomical and functional changes in corneal nerve function. Among the most commonly performed refractive surgery procedures are Laser Assisted In-situ Keratomileusis, Photorefractive Keratectomy, and Small Incision Lenticule Extraction. Due to differences in technique, these procedures can have varying effects on corneal nerve structure. Using in vivo confocal microscopy, postrefractive patients were found to have decreased total nerve density when compared with controls in the immediate postoperative period. In some studies, patients have been shown to undergo re-innervation and regain significant amounts of nerve function. The majority of studies have found that despite decreased nerve cell density, long-term outcomes of refractive surgery patients are generally favorable. However, loss of corneal nerve function can lead to a variety of serious effects ranging from dry eye disease, corneal hypoesthesia/anesthesia, neuropathic pain, to neurotrophic keratopathy and ulceration in the rare cases.
SUMMARY
Neurotrophic keratopathy is a rare occurrence after keratorefractive surgery and is largely due to damage to corneal nerves. Proper patient selection and counseling are essential to decrease the risk of development of this devastating complication.
Topics: Cornea; Corneal Diseases; Humans; Microscopy, Confocal; Photorefractive Keratectomy; Postoperative Complications
PubMed: 33989233
DOI: 10.1097/ICU.0000000000000769 -
Indian Journal of Ophthalmology Jan 2022To compare visual outcomes and vision-related quality of life (VRQoL) between subjects before and after photorefractive keratotomy (PRK) and controls. In addition, VRQoL...
PURPOSE
To compare visual outcomes and vision-related quality of life (VRQoL) between subjects before and after photorefractive keratotomy (PRK) and controls. In addition, VRQoL was compared between subjects at different periods of PRK surgery.
METHODS
This was a cross-sectional study that included subjects with refractive errors aged 19-40 years and age-matched controls. Subjects were divided into three groups: pre-, post-PRK, and control. Subjects in the post-PRK group were divided into three subgroups (1-week, <6-month, and >6-month follow-up visits). Measurements including uncorrected distance visual acuity (UCVA), corrected distance visual acuity (CDVA), spherical equivalent (SE) of manifest refraction, and corneal topography were obtained for all participants. The Quality of Life Impact of Refractive Correction (QIRC) questionnaire was administered to compare VRQOL between groups and between post-refractive surgery subgroups.
RESULTS
A total of 145 participants were included in this study. The mean age ± standard deviation (SD) of all participants was 26.29 ± 5.1 years. There was a significant difference (P < 0.001) in total QIRC scores between groups. The total QIRC score was better in the post-PRK group than in the pre-PRK and control groups. The scores of items included in the convenience, well-being, and health concern domains were significantly higher in the post-PRK group than in the pre-PRK and control groups. Within the post-PRK group, significant differences (P < 0.001) were found in UCVA and SE between the post-PRK subgroups. Uncorrected VA and SE were better in the post-PRK groups who were followed up in the < 6 and > 6 months subgroups than in the 1-week follow-up subgroup (P < 0.0001).
CONCLUSION
A significant improvement in visual outcomes and VRQoL occurred after PRK surgery. Subjects enjoyed their VRQoL after refractive surgery.
Topics: Cross-Sectional Studies; Follow-Up Studies; Humans; Lasers, Excimer; Myopia; Photorefractive Keratectomy; Quality of Life; Refraction, Ocular; Treatment Outcome
PubMed: 34937209
DOI: 10.4103/ijo.IJO_16_21