Keratorefractive Surgery Research Articles

The main aspects of the diagnosis of dry eye syndrome in refractive patients

A comprehensive assessment of the condition of the ocular surface was carried out in patients planning keratorefractive surgery using FemtoLASIK technology (30 eyes) and refractive lenticular extraction technology (30 eyes) with initially no subjective signs of dry eye syndrome. A comprehensive diagnostic approach to assessing the condition of the ocular surface, based on subjective and objective data, forms a holistic view of the homeostasis of the ocular surface in refractive profile patients, which will subsequently determine the choice of optimal laser vision correction technology, the tactics of patient administration and the featuress course of the postoperative period.

Reposition of dislocated piggyback intraocular lens in a patient with induced keratectasia after radial keratotomy

Aim – to substantiate low-traumatic sutureless surgery for piggyback intraocular lens (IOL) reposition as a method of choice in a patient after previous keratorefractive surgery and cataract phacoemulsification.
 The article provides the examination and surgical treatment data of one patient with piggyback intraocular lens dislocation after previous radial keratotomy and keratectasia.
 The presented clinical case shows that proper consideration of eye anatomical features allows for effective low-traumatic sutureless piggyback IOL reposition in patients who have previously undergone radial keratotomy, and may lead to sustainable high visual and functional results.

Optimizing Refractive Outcomes of SMILE: Artificial Intelligence versus Conventional State-of-the-Art Nomograms

Purpose AI (artificial intelligence)-based methodologies have become established tools for researchers and physicians in the entire field of ophthalmology. However, the potential of AI to optimize the refractive outcome of keratorefractive surgery by means of machine learning (ML)-based nomograms has not been exhausted yet. In this study, we wanted to comprehensively compare state-of-the-art conventional nomograms for Small-Incision-Lenticule-Extraction (SMILE) with a novel ML-based nomogram regarding both their spherical and astigmatic predictability. Methods A total of 1,342 eyes were analyzed for creation of three different nomograms based on a linear model (LM), a generalized additive mixed model (GAMM) and an artificial-neuronal-network (ANN), respectively. A total of 16 patient- and treatment-related features were included. Each model was trained by 895 eyes and validated by the remaining 447 eyes. Predictability was assessed by the difference between attempted and achieved change in spherical equivalent (SE) and the difference between target induced astigmatism (TIA) and surgically induced astigmatism (SIA). The root mean squared error (RMSE) of each model was computed as a measure of overall model performance. Results The RMSE of LM, GAMM and ANN were 0.355, 0.348 and 0.367 for the prediction of SE and 0.279, 0.278 and 0.290 for the astigmatic correction, respectively. By applying the created models, the theoretical yield of eyes within ±0.50 D of SE from target refraction improved from 82 to 83% (LM), 84% (GAMM) and 83% (ANN), respectively. Astigmatic outcomes showed an improvement of eyes within ±0.50 D from TIA from 90 to 93% (LM), 93% (GAMM) and 92% (ANN), respectively. Subjective manifest refraction was the single most influential covariate in all models. Conclusion Machine learning endorsed the validity of state-of-the-art linear and non-linear SMILE nomograms. However, improving the accuracy of subjective manifest refraction seems warranted for optimizing ±0.50 D SE predictability beyond an apparent methodological 90% limit.

Techniques in pediatric refractive surgery.

Pediatric refractive surgery treats refractive errors and their associated comorbidities such as amblyopia and strabismus in special needs children intolerant of spectacles or contact lenses. Children with neurobehavioral disorders undergoing refractive surgery have improvements in visual acuity, communication, socialization, motor skills, adaptive behaviors, visual perception, and cognitive function. Contrary to adults, amblyopia is frequently an indication for refractive surgery in special needs children. Pediatric refractive surgery techniques modify ametropia at the corneal, anterior chamber, posterior chamber, and lens planes. This article will discuss the most common modalities used today in pediatric refractive surgery, including laser keratorefractive surgery, phakic intraocular lenses, and refractive lens exchange. Practical pearls are discussed for the implementation of pediatric refractive surgery, reviewing preoperative diagnostics, surgical techniques, and postoperative care.

Effective optical zone following small incision lenticule extraction: a review.

Small incision lenticule extraction (SMILE) is a "flapless" keratorefractive surgery with excellent safety, efficacy, stability, and predictability for myopia correction. A recent global multicenter study also reported good refractive outcomes for hyperopic SMILE. SMILE has shown advantages including improved biomechanical strength, fewer dry eye symptoms, less corneal denervation, and fewer surgery-induced higher-order aberrations over laser in situ keratomileusis (LASIK). However, night vision complaints, including glare, halos, and starbursts, could still occur after SMILE. These symptoms have been proven to be closely related to the effective optical zone (EOZ), which is defined as the achieved area of corneal ablation. A larger postoperative EOZ may indicate better visual quality, making EOZ an important safety parameter for keratorefractive surgeries. As SMILE has gained wider application globally, the EOZ following SMILE has also been increasingly studied in the field of refractive surgery. This review provides an update on topics related to the EOZ after SMILE, including its measurement and influencing factors, aiming to benefit the personalization of the surgical algorithm and ultimately improve the visual quality after the SMILE procedure.

Тактика хирургического лечения пациента с непроникающей травмой роговицы, после ранее перенесенной операции ФемтоЛАЗИК (клинический случай)

Purpose. to present the tactics of surgical treatment of a patient with non-penetrating corneal trauma after previously undergone FemtolaSIK surgery. Material and methods. Patient m., 28 years old, addressed to the clinic of Volgograd branch with complaints of decreased visual acuity and feeling of foreign bODy on the right eye after trauma. during the repair of the braking system foreign bODies got into the right eye, which resulted in the rupture of the corneal flap in the paracentral region, with multiple metal foreign bODies getting into the corneal flap, under the corneal flap and into the stromal bed. Results. the patient underwent surgery: repositioning of the corneal flap with removal of multiple foreign bODies. mechanical partial deepithelization of the corneal flap in the zone of nonpenetrating corneal wound was performed. Foreign bODies and epithelial cells from the surface of the corneal bed and the back side of the epithelial-stromal flap were completely removed. the corneal flap was straightened and adapted. a soft contact lens was applied. Conclusion. repositioning of the corneal flap with removal of foreign bODies and epithelial cells in nonpenetrating corneal trauma allowed to preserve high visual functions in the patient after FemtolaSIK. Keywords: FemtoLASIK, keratorefractive surgery, corneal foreign body, non-penetrating corneal wound

Corneal edema caused by undiagnosed iridocorneal endothelial syndrome after SMILE

The aim. To present a clinical case of a patient with corneal edema caused by undiagnosed iridocorneal endothelial syndrome after SMILE surgery. Iridocorneal endothelial syndrome is characterized by abnormal proliferation of the corneal endothelium beyond the Schwalbe line, blockade of the iridocorneal angle, specific changes in the shape of the pupil and the formation of synechiae between adjacent structures of the anterior chamber angle of the eye, which is accompanied by the development of pretrabecular retention of intraocular aqueous humour, increased intraocular pressure (IOP) and subsequent development of glaucoma in 46–82 % of patients. One of the forms of the disease is Chandler’s syndrome, which clinically in the initial stages may be accompanied by the formation of only moderate ectropion. At the same time, endothelial dysfunction is characterized by a significant decrease in the number of cells, a change in their shape and the appearance of epithelioid cells with a hyper-reflective nucleus (the so-called “ICE (iridocorneal endothelial) cells”), with a violation of their natural pumping function. The article presents a clinical case of a patient who underwent a standard examination and symptomatic treatment after laser keratorefractive surgery for myopia correction. Low visual acuity, diffuse corneal edema, IOP decompensation of unclear genesis were observed in one operated eye. Conclusion. Keratorefractive operations can act as a trigger that stimulates the transition of the latent form into a clinically developed pathological process, which causes a decrease in corrected visual acuity due to the formation of corneal edema and glaucoma optic neuropathy.

Mitigated Residual Error in Inaccurate Myopic Keratorefractive Surgery.

Mitigated Residual Error in Inaccurate Myopic Keratorefractive Surgery.

The First Clinical and Functional Results of Myopia Correction Using a Solid-State Laser Unit

Relevance. Modern keratorefractive surgery (CRS) is a high-tech field of ophthalmology aimed at solving various problems of correcting a wide range of ametropias. Increasing the security of the RFI is one of the priority areas Purpose. To analyze the clinical and functional results of the use of the “Olimp™-2000” solid-state laser system during CRS using the method of superficial and sublamellar laser keratoablation and formulate recommendations for the therapeutic management of patients. Materials and methods. 53 patients (106 eyes) were examined, the average age was 28.5 ± 2.4 years. The inclusion criterion was moderate myopia and the absence of contraindications to CRC. If sufficient, taking into account safety criteria, CRS was performed by sublamellar keratoablation, if insufficient, superficial keratoablation was performed. In both cases, ablation was performed using a domestic solid-state laser machine. The observation period was 3 months. Pharmacological support in all cases was standard, adopted for the management of patients in FCMMG “YourMed”. Results. An analysis of the clinical and functional results of CRS using a solid-state laser device showed full compliance with the criteria set by the Food and Drug Administration (FDA). The accuracy of hitting the target refraction in the range of ± 0.5 diopters was 99.2 %; in 3 months of observation, no regression of the obtained refractive result was observed in any case. There was no loss of lines in any case, the BCVA after the operation corresponded to or exceeded by 1–2 lines the BCVA before the operation. When performing superficial keratoablation, in two cases, the loss of line 1 of the NCVA was noted due to the development of early subepithelial fibroplasia, which required correction of the pharmacological support. Conclusion. The analysis of the clinical and functional results of the correction of moderate myopia using the “Olimp™-2000” solid-state laser device showed high efficiency in terms of efficiency, safety, and predictability, despite little experience in using solid-state ablation in clinical practice. The use of Floas Mono® did not cause side effects in all cases and contributed to the smooth course of the early postoperative period. Thus, this drug is effective in the postoperative period and can be recommended for use in patients after CRC. The generation of ultraviolet radiation by modern solid-state devices for the purpose of correcting ametropia is a promising direction in CRS.

Сравнительный клинико-экономический анализ коррекции миопии с использованием лазерных кераторефракционных операций и контактных линз

Purpose. To conduct a comparative clinical and economic analysis of myopia correction using laser keratorefractive surgery and contact lenses. Material and methods. An analysis of direct medical costs was carried out for the following main items: the cost of surgery, contact lenses and solution for their injury. The sources of information were the official websites of 25 clinics and 13 opticians in Moscow. Calculations when using contact lenses were carried out for 312 days a year. All calculations are presented for 1 eye. Financial costs in the remote period were discounted at a rate of 5%. 1 USD = 78.32 rubles. Results. The median cost of the FemtoLASIK procedure was 76600 rubles, personalized FemtoLASIK – 82,000 rubles, refractive lenticular extraction – 110,000 rubles. The cost of one day of using contact lenses with a solution for their storage was: one-day – 83.0 (excluding the cost of the solution), 14-day – 29.0 rubles, 30-day – 21.5 rubles, 90-day – 8.2 rub. The cost of using one-day contact lenses after 5 years is 101,451 rubles, 14-day contact lenses with a storage solution – 35,447 rubles, 30-day – 26,279 rubles, 90-day – 10,023 rubles. Conclusion. The analysis revealed that the financial costs of one-day contact lenses already after 4 years exceed the cost of myopia correction using FemtoLASIK and personalized FemtoLASIK methods and amount to 85,219 rubles, and also after 6 years exceed the cost of refractive lenticular extraction operation and amount to 115,944 rubles. Keywords: cost-effectiveness, FemtoLASIK, SMILE, CLEAR, contact lenses

Внедрение в клиническую практику рефракционной экстракции лентикулы по методике SmartSight

Aim of the work is to analyze the clinical features of refractive lenticular extraction using SmartSight technology in patients with myopia and astigmatism, as well as to develop recommendations on the surgical technique of performing SmartSight surgery. Methods. 105 patients (210 eyes) were examined and treated using the SmartSight technique using the ATOS SCHWIND eye-tech-solutions femtosecond laser. Age was 18 to 40 years, myopia with MRSE from –2.00 to –8.50 D and astigmatism up to –2.75 D, with a range of keratometry parameters 41.00–46.00 D and pachymetric indicators of the smallest corneal thickness at least 500 µm, without contraindications to laser vision correction. Results. The analysis of clinical and functional results of myopia and astigmatism correction using the technology of refractive extraction of the lenticula performed using ATOS SCHWIND eye-tech-solutions femtosecond laser demonstrated high efficiency, safety, predictability of this technique. The MRSE within±0.50 D was achieved in 98 %. The efficiency index was 1.02±0.18. There was no case with comparative loss of 2 or more lines of BCDVA. No intraoperative complications were recorded. Conclusion. The SmartSight technique using the ATOS SCHWIND eye-tech-solutions femtosecond laser is a promising new development of refractive lenticular extraction technology for correction of myopia and myopic astigmatism. Key words: refractive lenticular extraction; keratorefractive surgery; myopia; astigmatism.

Willingness to Accept Keratorefractive Surgery and its Barriers among Myopes at Eye Foundation Hospital Group, Nigeria

The willingness to accept keratorefractive surgical services in this study was low. The main barriers to the uptake of the services were fear of damage, lack of awareness and financial constraints and there is a need for patient education to improve surgical uptake

Clinical features of dry eye syndrome and evaluation of the effectiveness of artificial tear therapy in patients with anxiety and depression after cataract and keratorefractive surgery

Introduction. Dry eye syndrome (DES) is a common cause of blurred vision and discomfort in patients after eye surgery, which has a great impact on the on the patients’ mental state. Evaluation of the presence of DES during the preoperative examination is important not only for obtaining a high postoperative result, but also for the timely administration of therapy in order to improve the patient's quality of life.Aim. Thus, the aim of this study was to establish the features of the clinical course of dry eye syndrome and to determine the effectiveness of ultra-high viscosity hyaluronic acid therapy in patients with anxiety and depression after cataract and keratorefractive surgery.Materials and methods. The study involved 100 patients (150 eyes). Preoperative examination included DES diagnostic and psychotesting. DES in all studied subjects was treated with ultra-high viscosity hyaluronic acid 3 times a day for 3 months after surgery in combination with topical combination of glucocorticoids, antibacterial and non-steroidal anti-inflammatory drugs, which were administered within 1 week after surgery. There were no intraoperative complications in all studied cases.Results. It was found that patients with depressive and/or anxiety symptoms (46% of the subjects) had higher OSDI scores, while there were no differences in clinical and functional tests of dry eye syndrome between the studied groups. There was a significant improvement in the results of OCT meniscometry and Norn's test during therapy with ultra-high viscosity hyaluronic acid. The given clinical examples show the importance of timely diagnosis and treatment of DES.Conclusions. The study showed the importance of dry eye syndrome evaluation and timely artificial tear therapy prescribing for both to achieve a high postoperative result and to reduce the patients’ subjective discomfort and improve patients’quality of life.

Correlation Between Corneal Keratometry, Central Corneal Thickness and Anterior Chamber Depth as Measured by Wavelight OB 820 Biometer and Wavelight Oculyzer II in Preoperative Cataract Surgery Patients.

To compare and correlate corneal keratometry (K), central corneal thickness (CCT), and anterior chamber depth (ACD) using a partial coherence interferometry device and a Scheimpflug camera system device in patients planned for cataract surgery. Comparative cross-sectional study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology, from December 2021 to June 2022. Patients planned for cataract surgery underwent measurement of central corneal thickness (CCT), anterior chamber depth (ACD), and keratometric values (K) by Wavelight OB 820 biometer and Allergo Oculyzer II, preoperatively. Correlation and inter-device agreement were assessed between two devices. There were 115 patients with a mean age of 64.23 ± 9.26 years. All anterior segment parameters showed excellent agreement and high degree of correlation between the two optical devices. Correlation coefficient (r) for central corneal thickness was r = 0.958 (p<0.001) while correlation coefficient for anterior chamber depth was r = 0.965 (p<0.001), r = 0.966 (p<0.001) for flat K, and r = .0969 (p<0.001) for steep keratometry, respectively. Ophthalmic parameters assessed by both devices were comparable and are recommended to be used in the clinical practice of keratorefractive and cataract surgeries interchangeably. ACD, CCT, Keratometry, Cataract, OB 820 biometer, Oculyzer II.

Comparison of total corneal power measurements obtained with different devices after myopic keratorefractive surgery.

To analyze the differences, agreements, and correlation among total corneal power parameters generated by different instruments after myopic keratorefractive surgery. The prospective cross-sectional study included patients who underwent myopic keratorefractive surgery and received measurements of corneal power 3mo after surgery. Automated keratometer was used for the measurement of simulated keratometry (SimK), swept-source optical coherence tomography (SS-OCT) based biometer for total keratometry (TK), anterior segment-OCT for real keratometry (RK), and Scheimpflug keratometer for the true net power (TNP), the total corneal refractive power (TCRP) and equivalent K-readings (EKR). The differences among these parameters were analyzed, and the agreements and correlation between SimK and other total corneal power parameters were investigated. A total of 70 eyes of 70 patients after myopic keratorefractive surgery were included. The evaluated corneal power parameters were as follows: SimK 38.32±1.93 D, TK 37.54±2.12 D, RK 36.64±2.09 D, TNP 36.56±1.97 D, TCRP 36.70±2.01 D, and EKR 37.55±2.00 D. Pairwise comparison showed that there were significant differences (P<0.001) among all parameters except for between TK and EKR, RK and TNP, RK and TCRP (P=1.000, 1.000, 1.000, respectively). The limits of agreement between SimK and TK, RK, TNP, TCPR, and EKR were 1.08, 1.08, 1.43, 1.48, and 1.73 D, respectively. All parameters showed good correlation with SimK, and the correlation coefficients were 0.995, 0.994, 0.983, 0.982, and 0.975. Among the corneal power parameters after myopic keratorefractive surgery, the value of SimK is the largest, followed by TK and EKR, with TCRP, RK, and TNP being the smallest. The differences among the parameters may be attributable to the different calculation principles. Correct understanding and evaluation of corneal power parameters can provide a theoretical basis for taking advantage of the total corneal power to improve the accuracy of intraocular lens calculation after keratorefractive surgery.

Синдром сухого глаза на фоне дисфункции мейбомиевых желез у пациента рефракционного профиля (клинический случай)

Purpose. To describe a clinical case of a patient planning keratorefractive surgery, diagnosed with dry eye syndrome (DES) on the background of meibomian gland dysfunction (MGD). Material and methods. Patient S. applied to the Department of laser refractive surgery of S.N. Fyodorov Eye Microsurgery Federal State Institution. She was 27 years old with a diagnosis of moderate myopia in both eyes for possible keratorefractive surgery. She underwent a standard refractive diagnosis and consultation with an ophthalmic surgeon. Results.During biomicroscopy and standard ophthalmological examinations of the ocular surface, patient S. was found to have DES and MGD. It was decided to conduct a course of conservative treatment to restore the ocular surface. Conclusion. Thus, the proposed utility model for the treatment of MGD and the associated DES makes it possible to normalize the secretory work of these glands and, as a result, stabilize the condition of the tear film, which contributes to the safe planning of keratorefractive surgery. Keywords: dry eye syndrome, dysfunction of the meibomian glands, tear film, keratorefractive surgery

Поиски возможностей минимизации интраоперационных осложнений кераторефракционной хирургии путем предварительной оценки психоэмоционального статуса пациентов

Purpose. to study the frequency and degree of mental tension among patients planned for keratorefractive surgery of myopia using the SMILE method. Material and methods. An in-depth psychological study of 145 patients scheduled for keratorefractive surgery was carried out. The average age of patients is 37 years. At the first stage, patients with an increased level of psychological anxiety were identified using the «Incomplete sentences» method. At the second stage, using the PSM-25 Psychological Stress Scale, among the selected patients, the degree of their mental tension was studied. Results. At the first stage, 42 patients (29 %) with an increased level of psychological anxiety were identified: 20 men and 22 women. Their average age was 35 years. At the second stage, it turned out that 9 patients had a high level of mental tension; 13 had medium level and 20 people had low level (the latter are psychologically stable). During a routine external examination and an interview with an ophthalmologist, patients with an average and high level of mental tension did not have any characteristic differences both from patients with a low level of mental tension and from other patients in the general population. Conclusions. When conducting a screening psychological test, 29% of patients with an unstable psychoemotional status were identified among the examined large population of patients planned for keratorefractive surgery of myopia. Among the selected patients with unstable psychoemotional status, 21.5 % had a high level of mental tension, 31 % have an average level and 47.5 % have a low level. Keywords: mental tension, preoperative stress; stress diagnosis

Progress of corneal morphological examination combined with biomechanical examination in preoperative screening for keratorefractive surgery.

Although corneal refractive surgery has been proven to be excellent in terms of safety and effectiveness, the reduction of postoperative corneal ectasia remains one of the most concerned topics for surgeons. Forme fruste keratoconus (FFKC) is the most important factor that leads to postoperative corneal ectasia, and common preoperative screenings of the condition include corneal morphology examination and corneal biomechanical examination. However, there are limitations to the single morphological examination or biomechanical examination, and the advantages of the combination of the two have been gradually emerging. The combined examination is more accurate in the diagnosis of FFKC and can provide a basis for determining suspected keratoconus. It allows one to measure the true intraocular pressure (IOP) before and after surgery and is recommended for older patients and those with allergic conjunctivitis. This article aims to discuss the application, advantages, and disadvantages of single examination and combined examination in the preoperative screening of refractive surgery, so as to provide a certain reference value for choosing suitable patients for surgery, improving surgical safety, and reducing the risk of postoperative ectasia.

The Combined Utilization of Epithelial Thickness Mapping and Tomography in Keratorefractive Surgery Screening: One Imaging Modality is Not Sufficient.

Increasing popularity and utility of epithelial thickness mapping (ETM) in keratorefractive surgery screening may begin to inappropriately devalue the use of tomography. An increasing body of research suggests that the interpretation of ETM based solely on the corneal resurfacing function may be insufficient to screen and select patients for refractive surgery. ETM and tomography are complementary and, when used together, may provide the safest and most optimal tools for keratorefractive surgery screening.

Role of tear vasoactive intestinal peptide on dry eyes after laser keratorefractive surgery

BackgroundTo explore the changes in vasoactive intestinal peptide (VIP) concentration in tears post laser-assisted sub-epithelial keratomileusis (LASEK) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgeries and related factors, possible association between postoperative dry eye symptoms and VIP concentration in tears, and factors influencing dry eye symptoms after different periods post LASEK and FS-LASIK surgeries.MethodsIn this prospective, non-randomized, longitudinal cohort study, 23 and 22 subjects were recruited and underwent LASEK and FS-LASIK, respectively. After conducting an intact ophthalmic examination and collecting relevant surgical data, all subjects were examined for VIP concentration in their tears using ELISAs, tear-film breakup time, ocular staining and ocular surface disease index questionnaire before surgery and 1 day, 1 week, and 1 month post-surgery.ResultsTear VIP concentration increased significantly after both LASEK and FS-LASIK, with the highest concentration observed 1 week post-surgery (P ≤ 0.05). Tear VIP concentration correlated negatively with corneal ablation depth (AD). The extent of dry eyes was related to the operation method employed and postoperative recovery period. In FS-LASIK and LASEK subjects, dry eyes were mainly affected by the basic ocular surface status before surgery, and VIP concentration. Furthermore, in LASEK subjects, dry eyes were negatively correlated with AD.ConclusionVIP was stimulated and mobilized as an emergency protection post-refractive surgery and a trauma model affected by AD. It can indirectly indicate the inevitable relationship between postoperative dry eye and nerve injury. Elevated post-surgery tear VIP relieves dry eye symptoms, showing its neuroimmune role in regulating adverse injury stimulation. The present study provides a solution to the pathogenesis of postoperative dry eyes.Trial registrationThe trial registration number: 2021JS22. Date of registration: 10 May 2021.