Corneal Flap Research Articles

Quantitative Evaluation of In Vivo Corneal Biomechanical Properties after SMILE and FLEx Surgery by Acoustic Radiation Force Optical Coherence Elastography.

The purpose of this study is to quantitatively evaluate the differences in corneal biomechanics after SMILE and FLEx surgery using an acoustic radiation force optical coherence elastography system (ARF-OCE) and to analyze the effect of the corneal cap on the integrity of corneal biomechanical properties. A custom ring array ultrasound transducer is used to excite corneal tissue to produce Lamb waves. Depth-resolved elastic modulus images of the in vivo cornea after refractive surgery were obtained based on the phase velocity of the Lamb wave. After refractive surgery, the average elastic modulus of the corneal flap decreased (71.7 ± 24.6 kPa), while the elastic modulus of the corneal cap increased (219.5 ± 54.9 kPa). The average elastic modulus of residual stromal bed (RSB) was increased after surgery, and the value after FLEx (305.8 ± 48.5 kPa) was significantly higher than that of SMILE (221.3 ± 43.2 kPa). Compared with FLEx, SMILE preserved most of the anterior stroma with less change in corneal biomechanics, which indicated that SMILE has an advantage in preserving the integrity of the corneal biomechanical properties. Therefore, the biomechanical properties of the cornea obtained by the ARF-OCE system may be one of the essential indicators for evaluating the safety of refractive surgery.

Фоторефрактивная кератэктомия как приоритетный метод докоррекции остаточных аметропий

Purpose. To show the effectiveness and safety of the correction of residual ametropia by the PRK method after previously performed keratorefractive operations LASIK, FemtoLASIK, ReLEx SMILE. Material and methods. All patients were divided into 3 groups: Group 1 – previously performed LASIK surgery with insufficient stroma thickness under the valve and patients with unknown parameters of the corneal flap operated in third-party clinics 35 patients (50 eyes), age 46.3 ± 21.9 years, the value of the spherical equivalent – 2.41 ± 1.45. Group 2 – patients after femtolasik 6 patients (6 eyes), age 30 ± 8.3 years, spherical equivalent value – 1.83 ± 0.76. Group 3 – patients after ReLExSMILE 8 patients (11 eyes), age 33 ± 4.4 years, spherical equivalent value – 0.88 ± 0.66. The minimum period after the initial keratorefractive surgery was 1 year, the maximum follow-up period was 4 years. Results. When analyzing the results 6 months after the operation of photorefractive keratectomy: group 1 – the value of the spherical equivalent – 0.26 ± 0.46; group 2 – 0.11 ± 0.2; group 3 – 0.19 ± 0.34. In Group 1, 4 patients (5 eyes) had a loss of lines (3 patients (4 eyes) – 1 line, 1 patient (1 eye) – 2 lines) of maximum visual acuity, all other patients had UDVA to CDVA before the operation of PRK. In groups 2 and 3, the maximum figures of visual acuity were taught. Conclusions. The use of transepithelial photorefractive keratectomy allows to obtain high clinical and functional results, is a safe, easy-to-perform, universal and highly effective method of correcting residual ametropias after various previously performed keratorefractive operations. Keywords: PRK, PRK after LASIK, PRK after FemtoLASIK, PRK after SMILE.

Efficiency of Moria One-Use Plus Sub-Bowman’s Keratomileusis Head in Achieving Predicted Corneal Flap Thickness in Sub Bowmans Keratomileusis

Purpose: To evaluate the difference between predicted and resultant corneal flap thickness in Sub-Bowmans Keratomileusis using Moria One-Use Plus sub-Bowman’s keratomileusis head. Study Design: Interventional case series. Place and Duration of Study: Liaquat National Hospital, Karachi, from April 2019 to September 2019. Methods: Total 55 patients of either gender with age 20 to 45 years undergoing Sub-bowmans Keratomileusis (SBK) were included. Frequencies and percentages were computed for qualitative variables. Quantitative variables were presented as mean ± standard deviation. Student t-test, pair t test and ANOVA were used to compare the mean of resultant and predicted corneal flap thickness. Effect modifiers were controlled through stratification. Post stratification student t-test was again used to compare the mean of resultant and predicted corneal flap thickness. P-value ≤ 0.05 was considered significant. Results: The mean age was 26.83 ± 4.38. There was an insignificant differences in preoperative, intraoperative and corneal flap thickness of both eye with respect to gender (P > 0.05). There was insignificant mean difference in preoperative and intraoperative corneal thickness (P > 0.05) of both eye with respect to age group but significant mean difference in resultant flap corneal thickness seen with both age group (P < 0.05). Significant difference was found in the flap thickness between the right and left eyes. The difference in the predicted and resultant flap thickness was statistically significant for right eye and insignificant for the left eye. Conclusion: With Moria microkeratome, accuracy of the flap can be predicted in SBK. It is a safe and effective method to achieve the desired results.

Three-Year Outcomes of Under-flap Stromal Bed CXL for Early Post-LASIK Ectasia.

To investigate the 36-month clinical outcomes of under-flap stromal bed CXL (ufCXL) and report on its ability to stabilize post-laser in situ keratomileusis (LASIK) ectasia. This case series included 20 eyes with diagnosed early post-LASIK ectasia treated with ufCXL. Inclusion criteria were early, mild post-LASIK ectasia, defined as new-onset postoperative manifest refraction cylinder of 1.50 diopters (D) or less, with new topographic inferior steepening consistent with ectasia, uncorrected distance visual acuity of 20/40 or better, and corrected distance visual acuity of 20/25 or better. The existing LASIK flap was lifted, 0.25% isotonic riboflavin was applied directly to the stromal bed, the flap was repositioned, and 18 mW/cm2 ultraviolet light was applied for 5 minutes to the corneal flap surface. Post-ufCXL ophthalmic data were compared to pre-ufCXL baseline measurements. Visual outcomes were maintained pre-ufCXL to 36 months post-ufCXL, with preserved safety index (P = .6545), efficacy index (P = .4980), spherical equivalent accuracy (P = .1536), defocus equivalent accuracy (P = .1032), central corneal thickness (P = .5196), and corneal irregularity indices at 3 mm (P = .8548) and 5 mm (P = .3399). Refractive astigmatism significantly decreased from 0.83 to 0.55 D pre-ufCXL to post-ufCXL (P = .0439), as did maximum keratometry from 42.40 to 42.00 D pre-ufCXL to post-ufCXL (P = .0420). The ufCXL demarcation line depth was 336 ± 21 µm post-ufCXL, with normal endothelial cell density (2,574 ± 203 cells/mm2). Only 1 of 20 eyes showed evidence of progression of 1.00 D in maximum keratometry. The ufCXL procedure shows promise in stabilizing early post-LASIK ectasia. Visual function, refractive astigmatism, maximum keratometry, and corneal irregularity indices were statistically maintained at 36 months postoperatively. [J Refract Surg. 2022;38(8):511-519.].

Flap Amputation and Mitomycin C Application as a Treatment For Corneal LASIK Flap Melting

Flap Amputation and Mitomycin C Application as a Treatment For Corneal LASIK Flap Melting

Femtosecond laser assisted superficial lamellar keratectomy as a successful treatment of corneal opacity in a patient with Thiel Behnke corneal dystrophy

Introduction and importanceThiel Behnke corneal dystrophy (TBCD) and Reis Buckler corneal dystrophy (RBCD) are Bowman's layer dystrophies with overlapping clinical features causing diagnostic confusion. However, each entity has typical histopathological features. We describe in this case the successful use of Femtosecond laser (FSL) in the treatment of TBCD-related corneal opacity.Case presentationWe present a 54-year-old male with bilateral superficial corneal opacities consistent with TBCD based on clinical appearance, anterior segment optical coherence tomography (AS-OCT), and In vivo confocal microscopy. Management options were discussed with the patient before proceeding with Femtosecond Laser Assisted Superficial Lamellar Keratectomy (FSLASLK). The histopathological findings of the excised left anterior lamellar corneal flap were typical of TBCD and the patient had a satisfactory outcome.Clinical discussionTBCD typically affects Bowman's layer centrally with progressive opacities involving the deeper layer of the corneal stroma and the periphery with advancing age. Histopathology typically shows subepithelial fibrosis with interrupted basement membrane and totally replaced Bowman's layer by uneven fibrous tissue forming the characteristic saw tooth pattern. The treatment of such cases is challenging with variable success and recurrence rates. Our case was managed successfully using FSL.ConclusionTBCD, even though a rare type of dystrophy, should be suspected based on the appearance of the corneal opacities clinically. It can be diagnosed by typical AS-OCT findings supported by histopathological confirmation and can be successfully treated by FSASLK.

Adhesion is safe to the refractive surgeries: A theoretical analysis

Adhesion behavior, existed on the damaged interface, was responsible for the safety and stability of the post-operative cornea refer to the refractive surgeries. In this study, we inferred that the force loss generated by the post-operative cornea must do not surpass the interfacial adhesion force of the cornea. In case of that, the corneal flap (or cap) would trend to separate from the residual stromal bed, and then became a threat to the visual health of the corrected myopic patient. According to this inference, we derived the theoretical maximum ablated ratio, which was well matched with the empirically clinical safety standard employing the commonly programmed optical zone.

Effects of Laser In Situ Keratomileusis and Small-Incision Lenticule Extraction on Corneal Biomechanical Behavior: A Finite Element Analysis.

Myopia, which is the result of the uncoordinated development of the eyeball, has become a major public health focus worldwide. Laser in situ keratomileusis (LASIK) and small-incision lenticule extraction (SMILE) have been successfully used in modern corneal refractive surgery. However, there are still controversies about postoperative results of LASIK and SMILE. In this study, a three-dimensional finite element model of the cornea was constructed based on the elevation and pachymetry data of a female volunteer. Surgical parameters, magnitudes of myopic correction, and intraocular pressure (IOP) were varied. Furthermore, an iterative algorithm was applied to retrieve the free-stress state of the intact corneal model, LASIK model, and SMILE model. To better evaluate the differences between LASIK and SMILE procedures, the displacement and Von Mises stress on the anterior and posterior corneal surface along the x- and y-axes were analyzed. Results for the zero-pressure model showed larger displacement compared to the image-based corneal model, suggesting that the initial corneal pre-stress stiffens the response of the cornea, both in the intact cornea and under refractive surgery. In addition, the displacement on the corneal surface in LASIK (both zero-pressure and image-based model) was obviously higher than that of the SMILE model. In contrast, SMILE increased Von Mises stress in the corneal cap and reduced Von Mises stress in the residual stromal bed compared with the LASIK model. However, the maximum Von Mises stress in the SMILE model was still smaller than that of the LASIK model. Moreover, the displacement and Von Mises stress on the residual stromal bed increased linearly with IOP. Overall, LASIK and SMILE refractive surgery could change biomechanical behaviors of the cornea. Compared to LASIK refractive surgery, SMILE may present a lower risk of ectasia. Creating a corneal cap rather than a corneal flap may have an advantage in improving corneal biomechanical stability.

CT Assessment of Vascular Density at Limbus Area after Excimer Laser Refractive Surgery in Myopic Patients

Purpose: to assess the indicators of vascular network density at limbus area in patients with myopia and myopic astigmatism before and after excimer laser refractive surgery.Material and methods. A total of 22 patients aged 18 to 37 years with myopia and myopic astigmatism of varying degrees, who previously underwent excimer laser refractive surgery, were examined. Additionally, the vascular network density at limbus area was assessed quantitatively in the preoperative and early postoperative periods using the Nidek RS-3000 AngioScan OCT device and utilizing a module for scanning the anterior segment of the eye.Results. One hour after excimer laser refraction surgery, there was a decrease in vascular network density at limbus area in all four analyzed sectors (upper, lower, temporal, nasal). One day after surgery, there was an increase in this indicator, tending to preoperative values. We were unable to identify the dependence of the degree of vascular network density on the method of corneal flap formation.Conclusion. OCT-angiography makes it possible to assess the indicators of vascular density at limbus area. The estimated indicators varied depending on the time passed after excimer laser refractive surgery.

Оценка показателя плотности сосудистой сети лимбальной области с помощью окт-ангиографии у пациентов с миопией и миопическим астигматизмом, перенесшим эксимерлазерную коррекцию зрения

Purpose. To assess the state of blood flow density in the limbal region in patients with myopia and myopic astigmatism before and after excimer laser vision correction using the Nidek RS-3000 AngioScan optical coherence tomograph. Material and methods. A total of 22 patients aged 18 to 37 years with myopia and myopic astigmatism of varying degrees were examined, who underwent excimer laser vision correction. Additionally, the blood flow density of the limbal region was studied in the preoperative and early postoperative periods using the Nidek RS-3000 AngioScan optical coherence tomograph using a module for scanning the anterior segment of the eye. Results. After 1 hour after excimer laser vision correction, there was a decrease in blood flow density of the limbal region in all 4 analyzed sectors (upper, lower, temporal, nasal), after 1 day there was an increase in blood flow indicators, tending to preoperative values. We were unable to identify the dependence of the degree of blood flow on the method of formation of the corneal flap. Conclusion. With the help of OCT angioregime, you can assess the state of the blood flow of the limb. In the first hour after laser vision correction, blood flow indicators changed in all 4 studied sectors, with a tendency to decrease, and recovered to preoperative indicators 1 day after surgery. Keywords: optical coherent angiography of the limbal region, excimer laser vision correction, femtolaser vision correction, myopia, myopic astigmatism.

Оценка показателей кровотока лимбальной области с помощью ангиорежима оптического когерентного томографа у пациентов с миопией и миопическим астигматизмом, перенесших эксимерлазерную коррекцию зрения

Purpose. To assess the state of blood flow in the limbal area in patients with myopia and myopic astigmatism before and after excimer laser vision correction using the Nidek RS-3000 AngioScan optical coherence tomograph. Material and methods. A total of 22 patients aged 18 to 37 with different degrees of myopia and myopic astigmatism who underwent excimer laser vision correction were examined. Additionally, the blood flow of the limbal area was studied in the preoperative and early postoperative periods using the Nidek RS-3000 AngioScan optical coherence tomograph using a module for scanning the anterior segment of the eye. Results. One hour after excimer laser vision correction, there is a decrease in blood flow of the limbal area in all 4 analyzed sectors (upper, lower, temporal, nasal), after 1 day there is an increase in blood flow indicators, tending to preoperative values. We were unable to identify the dependence of the degree of blood flow on the method of formation of the corneal flap. Conclusion. Using OCT angioregime it is possible to assess the condition of limb blood flow. In the first hour after laser vision correction blood flow parameters change in all 4 studied sectors, with a tendency to decrease, and recover to preoperative values 1 day after the surgery. Key words: optical coherent angiography of the limbal area, excimer laser vision correction, femtolaser vision correction, myopia, myopic astigmatism.

Assessment of post-LASIK flap thickness created by mechanical microkeratomes by anterior segment optical coherence tomography

Background and aim Laser-assisted in situ keratomileusis (LASIK) is the most popular refractive surgical operation for the correction of myopia, hyperopia, and astigmatism. Corneal flap creation is an essential step for the success of LASIK. The aim of the work is to evaluate the accuracy of the post-LASIK flap thickness created by mechanical microkeratomes using Anterior segment optical coherence tomography (ASOCT). Patients and methods This study included 60 eyes (of 30 patients), who underwent LASIK for refractive error correction. The patients were divided into two groups: (a) group A involved 30 eyes of 15 patients; in this group, the mechanical microkeratome Moria M2 (Moria M2, 110) was used. (b) Group B involved 30 eyes of 15 patients; in this group, the microkeratome Moria M2 (Moria M2, 100 with medlogic plano head) was used. Results As regards postoperative changes in flap thickness, the results of the current study showed that there were no considerable changes in thickness of the flap between 1 week, 1 month, 3 months, and 6 months postoperatively in either group. Conclusion Moria M2 100 with medlogic plano head created LASIK flaps with thinner thickness, and more predictability and more preservation of bed thickness than those created with the Moria M2 110.

Clinical Pearls in Postoperative LASIK Management

More than 35 million LASIK procedures have been performed worldwide with reported improvement in outcomes and safety.1 With proper preoperative screening and advanced technology, visual outcomes are excellent with a low complication rate. This paper reviews potential LASIK complications and treatment options. The majority of complications are minor and resolve with treatment without any adverse effects on visual acuity or quality of vision. Over the past 30 years, there have been significant advances in excimer laser technology, which include improved nomograms, flying spot lasers to deliver smoother ablations, accurate trackers, larger optical zones, aspheric curves, and customized treatments that reduce not only refractive errors but other optical aberrations of the eye. In North America, femtosecond lasers for creation of the corneal flap have generally replaced mechanical microkeratomes that require a blade. Advances in femtosecond technology have shown predictable flap thickness and the ability to customize the diameter, location, hinge, and edge profile of the LASIK flap. CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Click here to Enroll (https://www.crojournal.com/clinical-pearls-in-postoperative-lasik-management)

Research progress of epithelial ingrowth under corneal flap after keratorefractive surgery

Research progress of epithelial ingrowth under corneal flap after keratorefractive surgery

A Simple Inner-Stopper Guarded Trephine for Creation of Uniform Keratectomy Wounds in Rodents.

PurposeCreating controllable, reproducible keratectomy wounds in rodent corneas can be a challenge due to their small size, thickness, and the lack of usual tools available for human eyes such as a vacuum trephine. The purpose of this work is to provide a consistent, reproducible corneal stromal defect in rats using a simple, economical, and customized inner-stopper guarded trephine.MethodsThe inner-stopper guarded trephine is used to induce a circular wound in rat corneas. After trephination, the corneal flap can be removed by manual dissection using a blunt spatula. We used optical coherence topography (OCT) to measure the defect wound depth induced in ex vivo rat eyes.ResultsDespite a minor learning curve, this simple device enables depth control, reduces variability of manual keratectomy wound depth in rats, and decreases the risk for corneal perforation during keratectomy. Corneal defect creation was highly reproducible across different researchers and was independent of their surgical training.ConclusionThis inner-stopper guarded trephine can be utilized and applied to pre-clinical testing of a wide range of corneal wound healing therapies, including but not limited to biotherapeutics, corneal prosthetics, and regenerative technologies.

Outcome of PRK and LASIK for the Initial 100 Cases at Kirkuk City

Background: Despite that LASIK showed faster visual recovery after the operation, there was no considerable variation in the visual results between LASIK and PRK with long term- follow up. Aim of study: To assess the outcome of photorefractive keratectomy (PRK) and laser (or laser-assisted) in situ keratomileusis (LASIK) for the initial 100 cases in the same center at Kirkuk city. Patients and Methods: This clinical study was designed as a prospective, 6-month clinical study. A total 198 eyes of 100 patients entered the study cohort: 141 randomized to LASIK and 57 to PRK. All patients received a one-pass, multizone excimer laser ablation as part of either PRK or LASIK procedure using the Alcon Allegretto excimer laser. The preoperative manifest spherical equivalent ranged from -9.25 diopters (D) to +5.0 D for the LASIK group and -4.50 D to -0.6 D for the PRK group. Results: At 6 months after surgery, 43 (75.4%) and 10 (17.5%) eyes in the PRK group achieved UCVA of 6/6 and 6/12 or better respectively, while after LASIK, 63 (44.6%) and 71 (50.3 %) eyes achieved UCVA of 6/6 and 6/12 or better, respectively. After PRK 56 (98.2%) eyes were within 1.0 D of attempted correction compared to 132 (92.7%) eyes in the LASIK group. At 6 months postoperatively, most of the eyes (85 eyes in the LASIK group and 43 eyes in the PRK group) achieved UCVA line similar to the preoperative BCVA line. No significant complications at operation were seen in any PRK cases. For LASIK-treated eyes, five eyes (3.5%) had intraoperative flap complications, four incomplete flaps and one button hole. All these cases were treated with PRK after one month. All incomplete flap cases got final UCVA of 6/6, while buttonhole flap case achieved final UCVA of 6/18. Conclusions: The essential outcomes of both LASIK and PRK in this study show no significant differences in efficacy at 6-months follow-up. Both LASIK and PRK seems to be relatively effective and safe procedure for myopia and hypermetropia. PRK has the advantage of easier surgery without corneal flap complications, while LASIK offers the advantages of minimal discomfort and faster visual rehabilitation.

Treating intrasurgical complications of corneal refractive operation with customized ablation. A clinical case

Purpose: to evaluate the prospects of customized Finalfit based ablation for optical rehabilitation of a patient with corneal surface errors caused by intrasurgical microtome-induced damage of a corneal flap during a LASIK excimer laser correction of vision.Material and methods. In Helmholtz Center, a patient with such damage was given a phototherapeutic keratectomy (PTK) combined with topographyguided photorefractive keratectomy.Results. In two months after the surgery, the patient’s uncorrected visual acuity rose from 0.15 to 1.0; the spherical component of refraction changed from -3.5 to +1.0 D, the cylindrical component of refraction fell from 1.75 to 0.25 D. Aberrometry demonstrated a decrease of RMS from 2.19 to 0.61 D, Total HOAs from 2.281 to 0.829; Tilt from 0.406 to 0.313; HOA from 1.152 to 0.247, Coma from 0.298 to 0.124, Trefoil from 1.088 to 0.094, SA from 0,127 to 0,021.Conclusion. The clinical case demonstrates the expediency and efficiency of corneal remodeling for the rehabilitation of induced errors of the corneal surface by excimer laser correction of vision based on PTK (Flex scan) + FinalFit after corneal refractive surgery.

Flap Thickness and the Risk of Complications in Mechanical Microkeratome and Femtosecond Laser In Situ Keratomileusis: A Literature Review and Statistical Analysis.

Introduction: A recent Cochrane review found no difference in visual acuity outcomes between femtosecond-assisted laser in situ keratomileusis (LASIK) and LASIK using mechanical microkeratomes (MMKs). This study compares the flap thickness and risk of complications related to flap creation using femtosecond lasers and MMKs. Methods: PubMed and the Web of Science are used to search the medical literature. An extensive search is performed to identify the flap thickness and complications of LASIK as reported up to 15 July 2021. The following keywords are used in various combinations: Corneal flap, femtosecond laser, laser in situ keratomileusis, laser-assisted in situ keratomileusis, LASIK, mechanical microkeratome. Results: After removing duplicates and irrelevant studies, 122 articles were included for review. Pooled differences for intended vs. postoperative flap thickness using MMKs and femtosecond laser were −4.07 μm (95% CI: −19.55, 3.24 μm) in studies on the MMK and 5.43 μm (95% CI: 2.30, 7.84 μm; p < 0.001), respectively. After removing the studies evaluating outcomes of the old generation Hansatome MMKs (which had a significantly greater variation of flap thickness), the pooled difference for newer MMKs was 4.97 μm (95% CI: 0.35, 9.58 μm; p < 0.001), but the results still favored the femtosecond laser. Uncommon and mild complications unique for the femtosecond LASIK are epithelial gas breakthrough, opaque bubble layer, transient light sensitivity syndrome, and rainbow glare. A single study reported a very low, but stastically different risk of postoperative flap slippage (0.033% for MMK LASIK, and 0.003% for femtosecond LASIK, respectively). Conclusion: In both manual microkeratome and femtosecond LASIK, intra- and postoperative complications were uncommon. The evidence of the superiority of one technique in terms of complications over another cannot be indisputably stated.

Repair of a corneal laceration and iris prolapse in a juvenile goliath tigerfish (Hydrocynus goliath)

AbstractA juvenile goliath tigerfish (Hydrocynus goliath) was presented with a traumatic full‐thickness corneal laceration and associated iris prolapse. Debridement and corneal flap repair using N‐butyl cyanoacrylate tissue glue was performed under general anaesthesia. This article describes the initial ocular surgery and documents the recovery and healing process over the following 3‐week period. The fish was discharged from treatment at this point, and there were no complications over the ensuing 1‐year period.

Методика акселерированного кросслинкинга с использованием защитного донорского лоскута роговицы в лечении прогрессирующего кератоконуса на «тонких» роговицах

Purpose. To develop a method of accelerated ultraviolet crosslinking with an initial corneal thickness equal to or less than 400 microns using a protective donor corneal flap. Definition of safety and effectiveness of this method in the treatment of progressive keratoconus. Material and methods. 20 patients (20 eyes) with a diagnosis of progressive keratoconus 2–3 stages were included in the study. The accelerated crosslinking was carried out with an IROC-VX-2000 device (Switzerland). A protective donor corneal flap was cut out by using a Femto LDV Z8 femtosecond laser (Ziemer, Switzerland). The thickness of the protective flap of the donor cornea was determined as the difference between 450 μm and the obtained value of the patient's pachymetry in 30 minutes of saturation with Dextralink in μm. Results. Indicators of uncorrected visual acuity and corrected visual acuity returned to the level of preoperative values and did not tend to decrease until the end of the observation period for 6 months. The average keratometry indices gradually decreased: after 3 months – 50.3 ± 1.5 μm, after 6 months – 48.9 ± 1.8 μm, by 12 months – 46.7 ± 2.1 μm. A decrease in elevation indicators of the anterior and posterior surfaces was marked on elevation maps throughout the observation period. Conclusion. The proposed ultraviolet crosslinking technique using a protective donor corneal flap in patients with corneal thickness 400 μm or less is reproducible. This technique proves its effectiveness and safety and allows to stabilize the condition in patients with progressive keratoconus with adequate visual function. This makes this technique necessary, taking into account the lack of adequate cross-linking technology with a thin cornea. Keywords: progressive keratoconus, thin cornea, ultraviolet crosslinking, protective donor corneal flap.