Recent trends of refractive surgery rate and detailed analysis of subjects with refractive surgery: The 2008-2015 Korean National Health and Nutrition Examination Survey.

The present study was conducted to investigate recent trends of refractive surgery rates and analyze subjects undergoing refractive surgery using large-scale population studies over the past 8 years. We used the dataset of the Korean National Health and Nutrition Examination Surveys, a nationwide population-based cross-sectional study which were performed from 2008 to 2015. Of the 21,415 participants aged 20 to 49 years, 1,621 had refractive surgeries. Seventy three percent of them were females and 81% of them were aged under 40 years old. Over the past 8 years, cumulative prevalence of refractive surgery rate increased more than 10%. Although young (< 40 years, odds ratio (OR) 0.31, P<0.001) women (OR 1.86, P<0.001) living in urban areas (OR 0.51, P<0.001) with high educational attainment (OR 2.67, P<0.001) and income levels (OR 3.16, P<0.001) accounted for a high proportion in refractive surgery group through all survey years, subgroup analyses revealed that gaps between genders (ORs 3.8 in 2008-2009, 2.1 in 2010-2012, and 1.5 in 2013-2015), educational level (ORs 3.0, 2.5, and 2.1, respectively), and highest/lowest quartiles of household income (ORs 5.2, 2.6, and 2.4, respectively) were decreasing over time. Overall, our study suggests that refractive surgery has reached an age where the majority accepts it, and indeed more and diverse people are undergoing refractive surgeries.

Research Progress of the Application of Hypothermia in the Eye.

Hypothermia is widely used in the medical field to protect organs or tissues from damage. Different research fields have different explanations of the protection mechanism of hypothermia. Hypothermia is also widely used in the field of ophthalmology, for example, in the eye bank, the preservation of corneal tissue and the preservation of the eyeball. Low temperature can also be applied to some ophthalmic diseases, such as allergic conjunctivitis, retinal ischemia, and retinal hypoxia. It is used to relieve eye symptoms or reduce tissue damage. Hypothermic techniques have important applications in ophthalmic surgery, such as corneal refractive surgery, vitrectomy surgery, and ciliary body cryotherapy for end-stage glaucoma. Hypothermia can reduce the inflammation of the cornea and protect the retinal tissue. The eyeball is a complex organ, including collagen tissue of the eyeball wall and retinal nerve tissue and retinal blood vessels. The mechanism of low temperature protecting eye tissue is complicated. It is important to understand the mechanism of hypothermia and its applications in ophthalmology. This review introduces the mechanism of hypothermia and its application in the eye banks, eye diseases (allergic conjunctivitis, retinal ischemia, and hypoxia), and eye surgeries (corneal transplant surgery, corneal refractive surgery, and vitrectomy).

Comparison of the Trend of Excimer laser refractive surgery in Provinces of Iran between 2010 and 2014.

Purpose. The aim of the present study was to compare the trend of excimer laser refractive surgery in different provinces of Iran. Methods. This cross-sectional study was performed in 12 provinces of Iran in 2015 using the data of 2010 to 2014. A total of 28 surgical centers were selected. For each center, one week per season was randomly selected, giving a total of 20 weeks for all seasons of the study years. Then, to estimate the surgical rate in the selected provinces, since 4 weeks were selected each year, the number of operations on the 4 weeks was multiplied by 12.5 to generalize the results to 50 weeks (= 1 year). After applying the weight of each center, the number of refractive operations on each year was divided by the population of the province on that year, and reported per million population. Results. On average, Kermanshah (35.8%, P<0.001) and Tehran (3.1%, P<0.001) had the highest and lowest annual increase and Qom (11.8%, P<0.001) had the highest annual decrease in the rate of excimer laser refractive surgery, respectively. The highest rate was seen in Tehran in 2012 (8885 operations per million population) and the lowest rate was seen in Gilan in 2010 (142 operations per million population). Moreover, the concentration index was 0.25 in 2012, indicating a socioeconomic inequality in the rate of excimer laser refractive surgery. Conclusion. The results of the present study showed an increasing trend in the rate of the excimer laser refractive surgery in 9 Iranian provinces for the first time. Moreover, concerning the inequalities and the higher surgical rate in provinces with a better economic status, it is necessary to expand an insurance coverage and equip more public centers with the instruments and devices required for laser refractive surgery.

[The rapid development and changes of corneal refractive surgery in China].

Corneal refractive surgery in China, represented by laser corneal surgery, has undergone great changes in recent 30 years. Almost one million corneal refractive surgeries are performed each year. With the rapid technological innovation, the corrective effect is constantly higher, and complications are continuously controlled and reduced. The team of practitioners keeps expanding, and the academic strength is approaching the international level. With the application and promotion of various new technologies, the formulation of relevant norms and the increase of academic researches, corneal refractive surgery in China has stepped into the stage of diversification, intelligence and standardization. However, we should recognize the shortcomings while facing the great achievements. More efforts are still needed to provide the best visual quality and natural vision correction effect for patients. We would like to send congratulations on the 70th anniversary of Chinese Journal of Ophthalmology with this article. (Chin J Ophthalmol, 2020, 56: 81-85).

Optometry Research Agenda for the Next Decade: 20/20 by 2030 / Agenda de Investigación en Optometría para la Próxima Década: 20/20 para 203

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Refractive surgery.

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.

[SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018 (French translation of the article)]. / Quelle place pour le SMILE (Small Incision Lenticule Extraction) dans la chirurgie réfractive cornéenne en 2018.

Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (Small Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to disadvantages of the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia with LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding improvements in the technique.

Investigation of the Changes in Refractive Surgery Trends in Korea.

PURPOSE: To evaluate changes in clinical practice in the field of refractive surgery in Korea over the past 10 years. METHODS: A survey consisting of 59 multiple-choice questions regarding the preferred types of refractive surgery, excimer laser machine, and presbyopia surgery was mailed to 742 members of the Korean Society of Cataract and Refractive Surgery in January 2016, and 50 members responded to the survey. These data were compared with the 2005 or 2007 survey results. RESULTS: The majority of respondents were in their 40s (54%), and the average number of refractive surgeries performed in one month was 53. The most commonly used excimer laser machine was the VISX S4 in both 2005 (32%) and 2015 (25%); however, a greater variety of machines (EX500 [18%], Allegretto wave Eye-Q [13%], AMARIS 750 [10%]) were used in 2015. The preferred corneal refractive surgery in 2015 was surface ablation (40%), representing a significant increase in its popularity compared to 2005 (15%) (p < 0.001). The popularity of laser in situ keratomileusis (LASIK) surgery decreased to 20% in 2015 compared to 48% in 2005 (p < 0.001). Eighty percent of LASIK procedures in 2015 were performed using femtosecond laser. In 2015, surface ablation and phakic intraocular lens implantation were preferred for the treatment of myopia less than -8 diopters and more than -8 diopters, respectively. The proportion of respondents performing presbyopia surgery in 2015 (76%) was significantly increased from 2007 (30%) (p < 0.001). CONCLUSIONS: Over the past decade, the most commonly performed corneal refractive surgery has changed from LASIK to surface ablation, and there has been a significant increase in the popularity of presbyopia surgery.

Advances in Refractive Surgery: June 2014 to July 2015.

PURPOSE: The objective of this study was to review the advances in the field of refractive surgery as reported in the peer-reviewed literature during the previous year. DESIGN: A literature review. METHODS: In this review, we highlight the most pertinent articles in the field from June 2014 to the end of July 2015. RESULTS: This past year has seen a growing body of research on small-incision lenticule extraction, presbyopic inlays, and phakic intraocular lenses, as more clinicians are adopting these techniques into their armamentarium. CONCLUSIONS: Laser-assisted in situ keratomileusis and photorefractive keratectomy continue to dominate the keratorefractive literature, as they remain the most frequently performed refractive surgeries.

[Advance of femtosecond small incision lenticule extraction (SMILE) in clinic application].

Femtosecond small incision lenticule extraction (SMILE) had been performed in clinic more than 5 years in China. With the gradual development of the technology, SMILE has caused more and more attention because of the remarkable clinical effect, micro incision, minimally invasive and refractive stability. The reuse of the refractive lenticule (RL) from SMILE has recently become extensive focus, which brings potential method to corneal refractive surgery from subtraction to addition. This review has clarified the technology of SMILE on the aspects of corneal refractive correct, the clinical effect of reuse the materials (RL), the basis of related research and the possible improvement in the future.

Research Progress on Ocular Surface Changes after Fem- tosecond Laser Small Incision Lenticule Extraction.

The femtosecond laser has a number of advantages, such as short pulse time, high instantaneous power, high repetition rate, low monopulse energy, and small thermal effect. Femtosecond laser-assisted small incision lenticule extraction (SMILE) is becoming the new direction in refractive surgery, and the ocular surface changes after SMILE are attracting increasingly more attention. This article reviews adverse effects, including dry eye, injury of corneal nerves, and ocular surface inflammation, occurring after SMILE.

Advances in Refractive Surgery: May 2013 to June 2014.

PURPOSE: The field of refractive surgery is changing quickly in the areas of screening, treatment, and postoperative management. The objective of this study was to review advances in the field of refractive surgery as reported in the peer-reviewed literature during the previous year. DESIGN: This was a literature review. METHODS: In this article, we highlight the progression in the field from May 2013 to the end of June 2014. This article is organized as preoperative, intraoperative, and postoperative considerations. RESULTS: The growing use of newer modalities of treatment, such as small-incision lenticule extraction (SmILE) and phakic intraocular lenses, and their safety and efficacy add to the armamentarium in treating refractive error. This past year has seen many studies, which show these procedures to be safe and effective. Also, structurally, SmILE may result in a more biomechanically stable cornea, so that we may be able to safely treat higher refractive errors. CONCLUSIONS: While laser-assisted in situ keratomileusis is the predominant surgical procedure, photorefractive keratectomy is still an appropriate choice in certain scenarios (higher risk for ectasia postrefractive surgery and patient choice) with safe, predictable results, and patient satisfaction. Many of the new developments in laser-assisted in situ keratomileusis have focused on flap creation with femtosecond lasers. Histopathology and in vivo optical coherence tomography studies have shown that the stromal bed is smoother, the side cuts are vertical, and the flap has predictable thickness. New surgical modalities, such as femtosecond lenticule extraction and SmILE, are increasingly being used.

[Keratoconus: modern approaches to pathogenetic studies, diagnosis, optical correction, and treatment].

OBJECTIVE: To evaluate modern approaches to pathogenetic studies, diagnosis, optical correction, and treatment of keratoconus (KC). MATERIAL AND METHODS: Research results over the recent years obtained with up-to-date methods of pathogenetic studying, diagnosis, correction, and treatment of KC are presented. RESULTS: Modern approaches to KC consist in analysis of corneal composition and trace elements migration as well as influencing factors. Topographic keratometry and pachymetry proved effective in early detection of KC. Results of intrastromal corneal segments implantation and corneal collagen cross-linking for optical correction and prevention of progression of KC are presented. The use of contact lenses and penetrative keratoplasty for optical correction in KC is comparatively analyzed. A new technique of complete corneal stromoplasty with viscoablation, which does not require anterior corneal stroma pre-separation and removal over the whole area of transplantation and ensures good visual control of Descemet's membrane separation, is suggested. Combined eximer laser photorefractive and phototherapeutic keratectomy for early keratoconus is theoretically substantiated. CONCLUSION: In most patients the discussed methods ensure prevention of progression of keratoconus, optical correction, and treatment. Prospects of further improvement of early diagnosis and treatment are associated with profound studying of the disease pathogenesis.

[Brazilian trends in refractive surgery]. / Censo Brasileiro de cirurgia refrativa.

PURPOSE: To determine preferences and practices of refractive surgeons in Brazil. METHODS: A cross-sectional study was conducted based on the data collected from a questionnaire applied during the VI Brazilian Congress of Cataract and Refractive Surgery and by e-mail sent to all members of that society. Refractive surgery techniques, use of emerging technologies, surgical volume, type of excimer laser and microkeratomes, mitomycin C, postoperative medications were analyzed among others questions. RESULTS: Two hundred ninety-two surgeons replied to the questions. The majority has a surgical volume between 2 and 4 eyes per week (57.60%). Most of the surgeons (64.50%) perform corneal tomography routinely and 22.00% of them do never customize their surgeries. The laser in situ keratomileusis (LASIK) is the main technique performed and when the photorefractive keratectomy (PRK) is applied; most of the surgeons uses mitomycin C (52.60%) in these patients. The excimer laser of choice was the Nidek (26.12%). CONCLUSION: LASIK is the preferred surgical procedure and the majority customizes their refractive surgeries. When photorefractive keratectomy is performed, mitomycin C is used by most of the surgeons (52.60%). Bilateral surgery is routinely performed and the femtosecond laser is still used by few refractive surgeons.

[Current state of refractive surgery of the cornea and lens]. / Derzeitiger Stand der refraktiven Chirurgie an Hornhaut und Linse.

Refractive surgery includes all procedures which are primarily targeted at changing the refractive power of the eye. Currently laser-assisted in situ keratomileusis (LASIK) is indicated to correct myopia of up to - 8 D, hyperopia up to + 3 D and astigmatism up to 5 D. Photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK) are primarily recommended for myopia up to - 6 D and for greater refractive errors, phakic intraocular lenses (IOL) are the first choice (myopia greater than - 6 D and hyperopia greater than + 3 D). If presbyopia is present in addition to the high refractive error, refractive lens exchange is another alternative.