Refractive lenticular extraction (ReLEx)

Refractive lenticular extraction (ReLEx) is the latest development in the long evolution of kerato-lenticular refractive procedure. Small incision Lenticule Extraction (SMILE) is minimally invasive and an innovative procedure. The refractive lenticule cut is performed using the state-of-the-art Femtosecond laser and the lenticule is extracted through small corneal incision. During the last 2 years, this most advanced SMILE procedure, has become clinically available in Europe and Asia as an alternative to LASIK for correction of high myopia. In the United States, the procedure is currently active and approved by the US Food and Drug Administration.

The FDA has issued pre-market approval for ReLEx SMILE to treat high myopia with astigmatism. The procedure, which is performed with the VisuMax femtosecond laser, may be potentially less disruptive to corneal surface tissue due to a small entry incision.

  • The first ReLEx SMILE procedure in the United States was performed by Jon G. Dishler, MD, at the Dishler Laser Institute in Colorado, ReLEx small incision lenticule extraction to treat myopia has been performed outside of the U.S. more than 700,000 times since 2011. The VisuMax femtosecond laser used to perform the minimally invasive procedure was approved by the FDA in September 2016. SMILE, the first major advancement in laser vision correction since the 1990s, promises to reinvigorate the refractive market by providing surgeons a new premium laser vision correction option for their practice,” Jim Mazzo, global president ophthalmic devices for Carl Zeiss Meditec, said in the release.
Khanna Institute Of Lasik
Khanna Institute Of Lasik

“The expansion of myopia treatment to patients with astigmatism will enable current and future SMILE surgeons to expand their patient base, paving the way for a new generation of refractive surgery patients.” 

There are several recognized corneal refractive surgery platforms and techniques to correct myopia, hyperopia, or astigmatism by changing the curvature of the cornea. The evaluation of efficacy and safety of ophthalmic treatments or procedures are conventionally subdivided into objective and subjective assessment categories. Key treatment evaluation indicators include the quantitative outcomes of visual acuity testing (corrected and uncorrected), keratometry, refractometry, contrast sensitivity, corneal high-order aberrations, nerve fiber regeneration, centration of the treatment zone, and corneal biomechanical properties. As the predictability of refractive correction and visual outcomes improve, patient satisfaction and managing patient expectations become key in the context of modern ophthalmology. Simply correcting the refractive error is no longer the only consideration, and patients, particularly those within the working-age population, expect that the procedure will positively influence their quality of life (QoL).

Fast and easy laser eye surgery with Dr.Rajesh Khanna of Khanna Vision Institute

Travelling the path

In the past lamellar keratoplasty (LK) and automated lamellar keratoplasty (ALK) were used to treat myopic refractive error. They involved the removal of a lenticule from the corneal stroma to flatten the central cornea and thus correct myopia using a mechanical microkeratome. Although introduced by Barraquer in the 1950s, it was only in the late 1980s and early 1990s wherein microkeratome reached a level of refinement. However, because of higher complications with mechanical microkeratomes LK techniques remained niche techniques to treat high myopia and never became part of the ophthalmic mainstream. The excimer laser was introduced in 1983 and was used on human eyes to reshape the cornea from 1988 by a procedure known as photo refractive keratectomy. It involved mechanical scraping of the corneal epithelium followed by reshaping of the remaining corneal bed with the excimer laser. It obtained US Food and Drug Administration approval in 1995 and quickly became the procedure of choice to treat refractive errors. However, because the corneal epithelium is removed, the patient experiences pain during the first post-operative day, the visual recovery is delayed, and there is a hyperopic overshoot for the first postoperative month. In some patients, especially higher myopes, it is seen that excimer laser PRK (photorefractive keratectomy) is followed by corneal haze and regression of the treatment. Today, despite significant improvements in laser ablation profiles, medication and wound – healing modulation regimens, and surgical technique, excimer laser PRK is performed on less than 20% of all refractive surgery patients. In the early 1990s, the work of Burratto et al and Pallikaris et al married the concept of ALK with the excimer laser in to a procedure known as laser-assisted in situ keratomileusis (LASIK). Laser-assisted insitu keratomileusis involves using a mechanical microkeratome to fashion a hinged flap of the cornea, with a thickness of 130 to160 microns. However, many surgeons have now adopted the femtosecond laseras their primary means to make LASIK flaps. The introduction of a femtosecond laser to make LASIK flaps has the advantages of making more predictable and safer flaps and relatively aberration neutral flap refractive surgery However, it also has some disadvantages. There is a need for two lasers to complete the procedure, namely, the femtosecond laser to make the flap and the excimer laser to perform the laser ablation of the refractive lenticule. This leads to significant extra capital and maintenance costs and the consumables and license fees for two lasers. There is also significant work flow disturbance within the laser suite, with the surgeon and the patient moving from one laser to another. The femtosecond laser can be used to carve out a lenticule within the corneal stroma. The lenticule can then be extracted from within the corneal stroma, either by creating and lifting a hinged flap similar to LASIK or by extricating it using a small incision in the cornea. These techniques of femtosecond lenticule extraction are known as femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE), respectively. Both techniques represent all-in-one femtosecond laser refractive surgery because they represent novel integrated surgical techniques to perform corneal laser surgery in a single step and need only one laser to perform laser refractive surgery and have various clinical, practical, and economic advantages over the more traditional two-laser solution. 

Selection criteria 

Currently ReLEx SMILE is available to treat myopic errors of up to – 10D spherical equivalent, with or without astigmatism of up to – 5D. It is at present not available for hyperopic correction. Patients are generally selected using the same criteria as LASIK. 

• Corneal topography: To rule out forme fruste keratoconus, pellucid marginal degeneration and posterior keratoconus. 

• Pachymetry: Thickness less than 480 microns or where the thickness of the cornea is likely to be less than 400 microns after the procedure are contraindicated. • Age: Should be older than 18 years. 

• Ocular history: No signs of lens changes, glaucoma, or other ocular problems. Any retinal breaks or holes, should be treated before the procedure. 

The machine The VisuMax Femtosecond laser is used to perform ReLEx SMILE procedure. The VisuMax is capable of creating refractive lenticules within the cornea with high degree of accuracy. The VisuMax software allows the calculation of the refractive lenticule needed for the correction of a particular refractive error and it also automates all stages of the procedure. 

Technique 

Under aseptic conditions and topical anesthesia, patients are prepared in a manner usual for LASIK. In ReLEx, the lenticule is carved out within the cornea by cutting action, as opposed to ablation with excimer laser which depends on a number of other factors like corneal hydration levels, atmospheric humidity and temperature and also on the depth in the stroma at which ablation occurs. The scatter in the ablation rates is particularly high, when ablation depth is large as in cases of higher refractive error. Because of the femtosecond lasers cutting action, the scatter in the thickness of the lenticule is minimized and it is independent of the refractive error being treated. 

Benefits as compared to LASIK

The refractive predictability with the ReLEx procedure is higher than with an excimer laser, particularly for higher amounts of refractive errors. With femtosecond laser, the peripheral loss of fluence is not a factor at all and no compensation needs to be carried out. So, the amount of tissue required per dioptre of treatment is smaller than that required with an excimer laser which compensates for the peripheral energy loss. The total amount of energy laid down into the cornea is also much less than with an excimer. Since there are some evidences that the fast heat generated by excimer laser has some adverse effect on corneal healing, the low energy used in ReLEx SMILE is a welcome benefit. The small incision heals relatively quickly, causes less patient discomfort and little risk of flap displacement. The small flap diameter and the small side-cut incision means that there is smaller likelihood of cutting corneal nerves, perhaps leading to less problems of dry eyes.  Finally, the procedure saves working time as there is no time loss in switching patients from one laser to another.

Conclusion

A study was conducted comprising prospective, single-center, consecutive series which included 118 patients, age 18–43 years. Fifty-six patients received ReLEx SMILE and 62 patients received Femto-LASIK surgery for correction of myopic astigmatism. Procedures were performed from March 2015 to May 2017 by two equally experienced refractive surgeons. The research was conducted at the Krasnodar Branch of Fyodorov Eye Microsurgery Federal State Institution in Krasnodar, Russia. Patients were not included in the series if they had other serious ocular disorders; neurologic and systemic diseases; myopic correction >8.5 D; corrected vision acuity <0.1 log MAR (poorer than 20/25 Snellen equivalent); “dry eye” syndrome; epitheliopathy; or previous inflammatory corneal diseases.

This study focused on addressing patients’ satisfaction and QoL following vision-correcting ReLEx SMILE and Femto-LASIK surgeries. In addition to traditional objective measurements of visual acuity and ophthalmic examination, the patient experience was evaluated using a QoL questionnaire. Results of the study confirm a positive visual acuity out come after treatment regardless of the surgical technique implemented. Improvements in QoL can be appreciated as early as the first day following surgery.

However, it is apparent that patients usually need some time to adapt to the new vision conditions and how these changes impact their daily lives as maximum QoL improvement was not achieved until later in the observation period. Long-term results from the study demonstrated high patient satisfaction with both methods. However, their findings revealed a higher satisfaction trend in QoL in those who received the ReLEx SMILE refractive correction.

As patient satisfaction is key in vision-correcting surgery, the addition of QoL assessment to traditional ophthalmic assessments offers a more detailed evaluation of patient outcomes. We recommend that QoL be included as best practice in the postoperative period to assess the results after corrective surgery.

Generated

ReLEX SMILE

Refractive lenticular extraction (ReLEx) is the most up to date advancement in the long evolution of kerato-lenticular refractive procedure. Small Cut Lenticule Removal (SMILE) is minimally intrusive and an innovative procedure. The refractive lenticule cut is done making use of the advanced Femtosecond laser and the lenticule is extracted with a tiny corneal incision. During the last 2 years, this most advanced SMILE treatment, has come to be scientifically available in Europe and also Asia as an alternative to LASIK for adjustment of high myopia. In the United States, the treatment is currently active as well as accepted by the US Food and Drug Administration.
The FDA has actually provided pre-market authorization for ReLEx SMILE to treat high near-sightedness with astigmatism. The treatment, which is executed with the VisuMax femtosecond laser, may be potentially less harmful to corneal surface tissue as a result of a small access cut.
– The initial ReLEx SMILE treatment in the United States was carried out by Jon G. Dishler, MD, at the Dishler Laser Institute in Colorado, ReLEx tiny incision lenticule removal to treat near-sightedness has actually been performed outside of the U.S. greater than 700,000 times since 2011. The VisuMax femtosecond laser made use of to execute the minimally intrusive procedure was approved by the FDA in September 2016. SMILE, the most significant improvement in laser vision correction since the 1990s, guarantees to revitalize the refractive market by offering cosmetic surgeons a brand-new premium laser vision modification alternative for their method,” Jim Mazzo, international head of state ophthalmic devices for Carl Zeiss Meditec, claimed in the press release.
“The growth of high myopia treatment to people with astigmatism will certainly allow current and future SMILE doctors to increase their patient base, leading the way for a new generation of refractive surgical treatment patients.”
There are numerous recognized corneal refractive surgery technologies as well as techniques to fix myopia, hyperopia, or astigmatism by changing the curvature of the cornea. The analysis of efficacy as well as safety and security of ocular treatments or procedures are conventionally partitioned into unbiased and also subjective evaluation categories. Key therapy assessment indicators include the measurable end results of visual acuity testing (dealt with and uncorrected), keratometry, refractometry, comparison level of sensitivity, corneal high-order aberrations, nerve fibre regrowth, centration of the therapy zone, and corneal biomechanical properties. As the predictability of refractive correction and visual end results improve, patient satisfaction as well as handling patient expectations become key in the context of modern-day ophthalmology. Simply dealing with the refractive error is no more the only consideration, and patients, especially those within the working-age population, expect that the treatment will positively influence their quality of life (QoL).
Travelling the course
In the past, lamellar keratoplasty (LK) as well as automated lamellar keratoplasty (ALK) were made use of to deal with short-sighted refractive error. They entailed the elimination of a lenticule from the corneal stroma to flatten the central cornea and hence correct myopia using a mechanical microkeratome. Although introduced by Barraquer in the 1950s, it was just in the late 1980s as well as early 1990s in which microkeratome reached a degree of refinement. Nevertheless, as a result of higher difficulties with mechanical microkeratomes, LK techniques remained particular niche strategies to deal with high near-sightedness and never ever entered into the ophthalmological mainstream. The excimer laser was introduced in 1983 as well as was utilized on human eyes to reshape the cornea from 1988 by a treatment referred to as image refractive keratectomy. It involved mechanical sculpting of the corneal epithelium complied with by improving of the remaining corneal bed with the excimer laser. It obtained US Food and Drug Administration approval in 1995 and swiftly came to be the procedure of option to deal with refractive errors. Nonetheless, because the corneal epithelium is removed, the patient experiences discomfort during the very first post-operative day, the visual recovery is delayed, as well as there is a hyperopic overshoot for the initial postoperative month. In some patients, particularly higher myopes, it is seen that excimer laser PRK (photorefractive keratectomy) is adhered to by corneal haze and regression of the therapy. Today, regardless of considerable improvements in laser ablation accounts, medication and wound-healing modulation regimens, and also surgical strategy, excimer laser PRK is performed on less than 20% of all refractive surgical treatment patients. In the very early 1990s, the job of Burratto et alia and Pallikaris et al married the concept of ALK with the excimer laser in to a treatment known as laser-assisted in situ keratomileusis (LASIK). Laser-assisted insitu keratomileusis entails utilizing a mechanical microkeratome to fashion a hinged flap of the cornea, with a density of 130 to160 microns. However, several cosmetic surgeons have now taken on the femtosecond laser as their primary method to make LASIK flaps. The introduction of a femtosecond laser to make LASIK flaps has the benefits of making the procedure much more dependable and also produce more safe flaps and is also a relatively aberration neutral flap refractive surgical procedure. Nonetheless, it also has some negative aspects. There is a requirement for two lasers to finish the procedure, namely, the femtosecond laser to make the flap as well as the excimer laser to execute the laser ablation of the refractive lenticule. This leads to considerable extra investment and upkeep costs and entails the consumables and license charges for 2 lasers. There is additionally considerable job flow disruption within the laser room, with the doctor and the patient relocating from one laser to another laser. The femtosecond laser can be made use of to carve out a lenticule within the corneal stroma. The lenticule can after that be extracted from within the corneal stroma, either by producing and also lifting a hinged flap similar to LASIK or by extricating it using a little cut in the cornea. These techniques of femtosecond lenticule removal are called femtosecond lenticule extraction (FLEx) in the former case and small-incision lenticule extraction (SMILE), in the latter case. Both techniques represent all-in-one femtosecond laser refractive surgical treatment due to the fact that they stand for unique integrated surgical methods to do corneal laser surgery in a solitary step and also need only one laser to perform laser refractive surgical treatment as well as have various professional, practical, and financial benefits over the even more typical two-laser technique, also known as LASIK.
Selection requirements
Currently ReLEx SMILE is offered to treat myopic errors of approximately -10 Dioptres (D) round equivalent, with or without astigmatism of up to – 5D. It not yet available for hyperopic correction. People are generally chosen using the exact same standards as LASIK.
Corneal topography: To rule out forme fruste keratoconus, pellucid minimal deterioration and back keratoconus.
Pachymetry: Density much less than 480 microns or where the density of the cornea is most likely to be less than 400 microns after the procedure are contraindicated. 

Age: Must be older than 18 years.
Eye background: No signs of lens modifications, glaucoma, or other ocular issues. Any kind of retinal breaks or openings, need to be treated prior to the treatment.

The machine The VisuMax Femtosecond laser is made use of to execute ReLEx SMILE treatment. The VisuMax is capable of creating refractive lenticules within the cornea with high level of precision. The VisuMax software enables the calculation of the refractive lenticule required for the modification of a particular refractive error and also it additionally automates all phases of the procedure.

Technique

Under aseptic conditions and topical anaesthetic, clients are prepared in a manner normal for LASIK. In ReLEx, the lenticule is carved out within the cornea by reducing action, as opposed to ablation with excimer laser which depends upon a number of other variables like corneal hydration levels, climatic moisture and temperature and additionally on the depth in the stroma at which ablation occurs. The scatter in the ablation rates is especially high, when ablation depth is large as in instances of higher refractive error. Because of the femtosecond laser’s cutting action, the scatter in the density of the lenticule is lessened and it is independent of the refractive error being treated.

Advantages as compared to LASIK


The refractive predictability with the ReLEx procedure is greater than with an excimer laser, especially for higher amounts of refractive errors. With femtosecond laser, the outer loss of fluence is not a factor in any way as well as no settlement requires to be performed. So, the amount of tissue needed per dioptre of therapy is smaller than that needed with an excimer laser which makes up for the peripheral energy loss. The overall quantity of power set right into the cornea is additionally a lot less than with an excimer. Considering that there are some evidences that the energy produced by the excimer laser has some negative impact on corneal recovery, the reduced power used in ReLEx SMILE is a welcome benefit. The small cut heals reasonably promptly, triggers less client discomfort as well as little risk of flap displacement. The tiny flap diameter as well as the little side-cut incision means that there is smaller probability of cutting corneal nerves, maybe bring about much less problems of completely dry eyes. Finally, the procedure saves functioning time as there is no time loss in switching people from one laser to another.

Conclusion

A research study was conducted comprising potential, single-centre, consecutive sets which included 118 clients, age 18– 43 years. Fifty-six clients obtained ReLEx SMILE and 62 clients got Femto-LASIK surgery for modification of myopic astigmatism. Procedures were executed from March 2015 to Might 2017 by 2 equally experienced refractive doctors. The study was conducted at the Krasnodar Branch of Fyodorov Eye Microsurgery Federal State Establishment in Krasnodar, Russia. Patients were not included in the sets if they had other serious eye disorders, viz. neurologic and systemic diseases; myopic correction >8.5 D; corrected vision acuity <0.1 log MAR (poorer than 20/25 Snellen equivalent); dry eye syndrome; epitheliopathy; or previous inflammatory corneal diseases.
This research study focused on resolving patient’s contentment as well as QoL following vision-correcting ReLEx SMILE and Femto-LASIK surgeries. In addition to typical unbiased measurements of visual acuity and ocular assessment, the patient experience was examined utilizing a QoL set of questions. Outcomes of the study verify a favourable visual acuity followed treatment irrespective of the surgical method carried out. Improvements in QoL can be seen as early as the initial day post-surgical treatment.
Nevertheless, it is apparent that people normally need a long time to adapt to the brand-new vision issues and just how these modifications impact their everyday lives as maximum QoL enhancement was not accomplished until later in the observation duration. Long-term results from the research demonstrated high patient satisfaction with both methods. Nonetheless, their findings reveal a greater satisfaction pattern in QoL in those who obtained the ReLEx SMILE refractive modification.
As patient complete satisfaction is vital in vision-correcting surgery, the addition of QoL analysis to typical ocular analyses uses an extra thorough assessment of patient outcomes. We recommend that QoL be included of as an ideal technique in the postoperative period to analyze the outcomes after rehabilitative surgical treatment.

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