Comparison of visual outcomes and optical aberrations after SMILE with intraoperative Kappa angle adjustments between small and large Kappa angles.

This study compares postoperative visual outcomes and optical aberrations after Small Incision Lenticule Extraction (SMILE) in patients with both small (S-Kappa: Kappa angle < 0.2 mm) and large Kappa (L-Kappa: Kappa angle ≥ 0.2 mm) angles. The evaluated aberrations include total higher-order aberrations (HOAs), horizontal coma (HC), vertical coma (VC), and spherical aberrations (SA), with procedures incorporating intraoperative Kappa angle adjustments. We retrospectively analyzed patient records undergoing SMILE utilizing linear mixed models (LMM). We assessed adjusted mean uncorrected distance visual acuity (UDVA), Strehl ratio (SR), total HOAs, VC, and SA at pupils of 3 mm and 6 mm for both S-Kappa and L-Kappa. The disparities between S-Kappa and L-Kappa were evaluated by LMM's adjusted mean differences. The differences in optical metrics were also assessed in eyes grouped by myopia levels: low, moderate, and high. A sensitivity analysis was conducted on a threshold of Kappa angle at 0.3 mm. Eight-five patients (169 eyes) were analyzed, and no significant pre-operative difference was found in UDVA (p = .222) or spherical equivalent (p = .433). Post-operative differences were found in SR at 3 mm pupil size (-0.06, p = .022), total HOA 3 mm (0.15, p = .022), HC 3 mm (0.04, p = .042), VC 3 mm and 6 mm (-0.08, p = .041; 0.04, p = .041). The stratified analysis for high myopia revealed significant differences in UDVA (-0.04, p = .037), HC 3 mm (0.07, p = .03), VC 6 mm (-0.21, p = .001), and SA 3 mm and 6 mm (0.07, p = .037; -0.09, p = .037). Sensitivity analysis showed no significant difference using a 0.3 mm Kappa threshold. While some optical aberrations exhibited statistical differences between S-Kappa and L-Kappa, their clinical significance is limited. Thus, a large Kappa angle might not substantially influence post-operative optical aberrations when intraoperative Kappa angle adjustments are implemented.

Association of myopia and astigmatism with postoperative ocular high order aberration after small incision lenticule extraction.

OBJECTIVE: To investigate the correlation between higher-order aberrations (HOA) after small incision lenticule extraction (SMILE) and the severity of myopia and astigmatism, along with the relevant factors. These findings will provide valuable insights for decreasing the occurrence of HOA after SMILE and enhancing visual quality. METHODS: A total of 75 patients (150 eyes) with myopia and astigmatism who underwent SMILE were categorized into four groups based on the severity of myopia and astigmatism: Myopia Group 1 (Group M1, spherical diopter ranged from -1.00 D to -4.00 D), Myopia Group 2 (Group M2, spherical diopter ranged from -4.10 D to -10.00 D), Astigmatism Group 1 (Group A1, cylindrical diopter ranged from 0 D to -1.00 D), and Astigmatism Group 2 (Group A2, cylindrical diopter ranged from -1.10 D to -3.00 D). A comprehensive assessment was performed to examine the association between HOA and various relevant factors, including a detailed analysis of the subgroups. RESULTS: Group M1 had significantly lower levels of total eye coma aberration (CA), corneal total HOA (tHOA), internal tHOA, and vertical CA ( Z 3 - 1 ) after SMILE than Group M2 (P < 0.05). Similarly, Group A1 had significantly lower levels of total eye tHOA, CA, trefoil aberration (TA), corneal tHOA, TA, and vertical TA ( Z 3 - 3 ) after SMILE than Group A2 (P < 0.05). Pearson correlation analysis indicated a statistically significant positive relationship between the severity of myopia/astigmatism and most HOA (P < 0.05). Subgroup evaluations demonstrated a notable increase in postoperative HOA associated with myopia and astigmatism in Groups M2 and A2 compared with the control group. Lenticule thickness, postoperative central corneal thickness (CCT), postoperative uncorrected distance visual acuity (UDVA), and postoperative corneal Km and Cyl were strongly correlated with most HOA. Age, eyes, and postoperative intraocular pressure (IOP) were only associated with specific HOA. CONCLUSION: HOA positively correlated with the severity of myopia and astigmatism after SMILE. However, this relationship was not linear. HOA after SMILE was influenced by various factors, and additional specialized investigations are required to establish its clinical importance.

Refraction and topographic risk factors for early myopic regression after small-incision lenticule extraction surgery.

We sought to evaluate the topographic risk factors for early myopic regression after small-incision lenticule extraction (SMILE). A retrospective case‒control study was conducted, and individuals who underwent SMILE surgery were enrolled. Among them, 406 and 14 eyes were categorized into the nonregression and regression groups, respectively. The preoperative and postoperative parameters in the two groups were collected, including spherical refraction (SE), axial length (AXL) and topographic data. A generalized linear model was adopted to analyze the difference in each parameter between the two groups. After 6 months, UCVA decreased in the regression group, and SE increased in the regression group (both P < 0.05). The increase in the CCT at the thinnest point (P = 0.044), flat corneal curvature (P = 0.012) and TCRP (P = 0.001) were significantly greater in the regression group. Regarding the risk factors for myopic regression, preoperative SE, preoperative sphere power, preoperative AXL, preoperative flat corneal curvature, preoperative SA, early postoperative SE, early postoperative sphere power, early postoperative AXL and early postoperative CCT difference were significantly greater in the regression group (all P < 0.05). The SE, sphere power, AXL, preoperative flat corneal curvature, preoperative SA, and postoperative CCT difference correlate with early myopic regression after SMILE.

Interface fluid syndrome caused by the corneal perforation injury after small incision lenticule extraction: a case report.

BACKGROUND: To report a case of interface fluid syndrome (IFS) following traumatic corneal perforation repair after small incision lenticule extraction (SMILE). CASE PRESENTATION: A 23-year-old woman, with a past history of SMILE, was struck in the left eye with a barbecue prod and subsequently underwent corneal perforation repair at local hospital. Primary wound repaired with a single 10 - 0 nylon suture at the area of leakage. After the surgery, her best corrected visual acuity (BCVA) was 20/30. Four days later, she presented at our hospital with blurred vision, and interface fluid syndrome (IFS) was diagnosed. Intraoperative optical coherence tomography (iOCT) was used to guide the resuturing of the corneal perforation in the left eye, followed by anterior chamber gas injection. At the first postoperative month, the BCVA was 20/25. The corneal cap adhered closely to the stroma, the surface became smooth. CONCLUSIONS: This case illustrates that any corneal perforation following lamellar surgery, including SMILE, may lead to IFS. It is crucial to consider the depth of corneal perforation, and intraoperative optical coherence tomography (iOCT) plays a unique role in the repair procedure.

[Peripheral sterile corneal infiltrates after small incision lenticule extraction].

A 31-year-old female patient with refractive error in both eyes underwent small incision lenticule extraction. On the 4th day after surgery, arc-shaped peripheral corneal infiltrates appeared in the right eye. Tobramycin and dexamethasone eye drops, 0.3% gatifloxacin eye drops, and a corneal bandage lens were applied to the eye. After bacterial infection was ruled out, dexamethasone sodium phosphate was injected subconjunctivally near the corneal lesion. The symptoms improved and the corneal lesion subsided afterwards.

Clinical outcomes of epithelial basement membrane dystrophy after keratorefractive lenticule extraction.

PURPOSE: To determine the clinical outcomes of keratorefractive lenticule extraction (KLEx) in eyes with epithelial basement membrane dystrophy (EBMD) that developed after surgery. SETTING: Onnuri Smile Eye Clinic, Seoul, South Korea. DESIGN: Retrospective single-center study. METHODS: This study reviewed the medical records of 26 eyes of 16 patients who exhibited signs of EBMD after KLEx. Postoperatively, corneal findings and visual outcomes were evaluated. Statistical analyses were also performed on eyes without corneal complications after KLEx. RESULTS: Signs of EBMD were first observed within 1 week postoperatively in 22 eyes (84.6%): 6 eyes (23.1%) showed epithelial defects, 10 eyes (38.5%) showed subepithelial corneal opacity, 5 eyes (19.2%) showed diffuse lamellar keratitis, and 1 eye (3.9%) showed epithelial ingrowth. Symptoms such as pain, while corneal lesions were present, occurred in 21 eyes (80.8%). At 3 months postoperatively, 21 eyes (80.8%) showed no specific findings on slitlamp microscopy after medical treatment, 2 eyes (7.7%) showed subepithelial corneal opacity, 2 eyes (7.7%) showed corneal scar, and 1 eye (3.9%) showed epithelial ingrowth. Uncorrected distance visual acuity was 20/25 or better in 24 eyes (92.3%), and spherical equivalent was within ±1.0 D in 20 eyes (76.9%). The efficacy index of the EBMD group did not significantly differ from the control group, while the safety index was significantly lower. CONCLUSIONS: Manifestations of EBMD can occur after KLEx and can affect clinical outcomes. Most cases showed favorable results with appropriate nonsurgical treatment; however, some cases had long-term complications such as corneal scarring.

Central corneal distortion after small-incision lenticule extraction.

A 33-year-old woman with a prior history of small-incision lenticule extraction (SMILE) presented with gradual deterioration of vision in her right eye since the surgery. She had undergone bilateral SMILE for myopic correction (-7.00 diopters [D] in the right eye and -6.00 D in the left eye) 3 weeks prior. SMILE was performed with a Zeiss VisuMax femtosecond laser system, with a cap thickness of 120 µm, a cap diameter of 7.50 mm, and a lenticule diameter of 6.50 mm. At the completion of the surgery, loose epithelium was noted at the SMILE incision bilaterally, and bandage contact lenses were placed in both eyes. On the first postoperative day, the patient's uncorrected distance visual acuity (UDVA) was 20/40 in both eyes. The bandage lenses were removed from both eyes, with the epithelium intact. At the first-week postoperative visit, her visual acuity was recorded as 20/30 in the right eye and 20/20 in the left eye. She noticed her vision in the right eye was not as sharp as that in her left eye. She denied experiencing any pain, redness, or ocular surface irritations. She was advised to return to the clinic for a 1-month postoperative visit and continue with aggressive lubrication in both eyes. However, a week later, the patient returned for an emergency visit, citing significant central visual distortion in the right eye and difficulty working on the computer. At this visit, her UDVA and corrected distance visual acuity (CDVA) was 20/50 in the right eye and 20/15 in the left eye at both near and far distances. A slitlamp examination revealed mild central changes in the right eye. She once again denied any pain, redness, or irritation. She was advised to continue with artificial tears and return to the office in 1 week for further observation of the central distortion in her right eye. Upon returning to the clinic at the third postoperative week, the patient still complained of central visual changes in the right eye, with a visual acuity of 20/70. Further slitlamp examination revealed a nonspecific central haze in the same eye, but there was no corneal staining or signs of epithelial defects. Anterior segment ocular coherence tomography (AS-OCT) and NIDEK topography were performed, showing the same central distortion in the right eye (Figures 1 and 2JOURNAL/jcrs/04.03/02158034-202311000-00016/figure1/v/2023-10-18T004638Z/r/image-tiffJOURNAL/jcrs/04.03/02158034-202311000-00016/figure2/v/2023-10-18T004638Z/r/image-tiff). Based on the examination and images provided, what is your working medical diagnosis? What other medical conditions are in your differential diagnosis? What medical and/or surgical interventions would you recommend, if any?

[Corneal ectasia following small-incision lenticule extraction: a case report].

A 22-year-old male presented with complaints of blurred vision in his right eye over the past 2 years following small incision lenticule extraction (SMILE) surgery conducted 4 years ago. Following a thorough ocular examination and evaluation, he was diagnosed with corneal ectasia in the right eye after the SMILE procedure. Subsequently, the patient underwent corneal cross-linking (CXL) treatment in the right eye to prevent the progression of the condition. After 3 months of treatment, the corneal ectasia remained stable. This article outlines the process of diagnosis and treatment, reviews the corneal conditions prior to the SMILE surgery, and analyzes the possible reasons behind the occurrence of postoperative corneal ectasia.

The dynamic changes and influencing factors of visual symptoms after small incision lenticule extraction.

BACKGROUND: To investigate the dynamic changes and influencing factors of visual symptoms after small incision lenticule extraction (SMILE). METHODS: This was a prospective observational study. Visual symptoms including glare, haloes, starbursts, hazy vision, fluctuation, blurred vision, double vision and focusing difficulties were evaluated before and 1, 3, 6 months after SMILE using a questionnaire. Generalized linear mixed models were used to assess the effects of preoperative characteristics and objective visual quality parameters on postoperative visual symptoms. RESULTS: 73 patients/146 eyes were enrolled. Preoperatively, the most common symptoms were glare (55% of eyes), haloes (48%), starbursts (44%) and blurred vision (37%). At 1 month postoperatively, the incidence and extent scores of glare, haloes, hazy vision and fluctuation rose significantly. At 3 months, the incidence and extent scores of glare, haloes and hazy vision restored to baseline. And at 6 months, the extent scores of fluctuation returned to baseline. Other symptoms (e.g., starbursts) did not change before and 1, 3, 6 months after SMILE. Preoperative visual symptoms were associated with postoperative symptoms, as patients with a symptom preoperatively had higher postoperative scores for that symptom. Age was related to postoperative extent of double vision (coefficient = 0.12, P = 0.046). There were no significant associations between postoperative visual symptoms and preoperative SE, scotopic pupil size, angle kappa (with intraoperative adjustment), postoperative HOAs or scattering indexes. CONCLUSIONS: The incidence and extent scores of hazy vision, glare, haloes and fluctuation increased at the first month after SMILE, and recovered to baseline at 3 or 6 months. Preoperative visual symptoms were associated with the postoperative symptoms and should be fully considered before SMILE.

The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis.

PURPOSE: To evaluate the effects of different programmed optical zones (POZs) on achieved corneal refractive power (CRP) with myopic astigmatism after small incision lenticule extraction (SMILE). METHODS: In total, 113 patients (113 eyes) were included in this retrospective study. The eyes were divided into two groups according to POZ: group A (6.5, 6.6, and 6.7 mm, n = 59) and group B (6.8, 6.9, and 7.0 mm, n = 54). Fourier vector analysis was applied to evaluate the error values between the attempted and achieved corneal refractive power (CRP). Alpins vector analysis was used to calculate surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME), and astigmatism correction index (ACI). Multivariate regression analysis was performed to assess potential factors associated with the error values. RESULTS: The error values in the group with large POZ were closer to zero, and significantly associated with the POZ at 2 and 4 mm of the cornea (ß = - 0.50, 95% confidence interval [CI] [- 0.80, - 0.20]; ß = - 0.37, 95% CI [- 0.63, - 0.10], P < 0.05, respectively). For the correction of astigmatism, the values of SIA, ME, and ACI were lower in group B than in group A (P < 0.05). The fitting curves between TIA and SIA were y = 0.83x + 0.19 (R2 = 0.84) and y = 1.05x + 0.04 (R2 = 0.90), respectively. CONCLUSIONS: Smaller POZs resulted in higher error values between the achieved- and attempted-CRP in the SMILE procedure, which should be considered when performing surgery.

New mechanism for epithelial ingrowth after small incision lenticule extraction: Vertical epithelial gas breakthrough.

A 41-year-old man underwent SMall Incision Lenticule Extraction (SMILE) to treat myopia in both eyes. The femtosecond procedure was uneventful but a paracentral epithelial blister appeared during the dissection of the anterior plane of the lenticule in the right eye. The posterior surface of the lenticule was dissected without any complication. The surgery of the left eye was uneventful. In the postoperative period, he developed a paracentral epithelial ingrowth in his right eye, exactly underneath the site where the epithelial blister had been noted during the dissection of the lenticule. This induced irregular astigmatism, severely affecting his visual acuity. The decision of surgical treatment was made. After the de-epithelialization of an area of 6mm around the ingrowth, the SMILE incision was opened, and the epithelial ingrowth was dissected and removed from the interface. One month later, uncorrected visual acuity was 20/20, no epithelial ingrowth was observed at the interface, and only the edge of the former ingrowth was barely visible in slit lamp examination. No recurrence was observed. We hypothesize that a vertical epithelial gas breakthrough created a fistula between the interface and the epithelium, forming a pathway for the epithelial cells and giving rise to epithelial ingrowth.

Case Report: Bilateral Corneal Ectasia Developed during Pregnancy after Small-incision Lenticule Extraction.

SIGNIFICANCE: This case highlights that hormonal changes during pregnancy could affect the biomechanical stability of the cornea and lead to corneal ectasia during pregnancy after corneal refractive surgery. PURPOSE: We report an unusual case of bilateral corneal ectasia after small-incision lenticule extraction that developed during pregnancy. CASE REPORT: A 27-year-old woman experienced post-small-incision lenticule extraction corneal ectasia. Her pre-operative corneal topography was normal, with a minimum central corneal thickness of 538 µm in the right eye and 530 µm in the left eye. The manifest refraction was -7.75 -0.25 × 180 and -7.50 -0.75 × 10, and the lenticule thickness was 140 and 139 µm in the right and left eyes, respectively. After 11 months, in her first trimester, the patient began to experience gradually deteriorating blurred vision. Two years post-operatively, corneal ectasia was diagnosed based on topographic data. The automatic optometer examination was -7.25 -2.50 × 42 in the right eye and -11.00 -5.00 × 140 in the left eye. Later, the patient underwent corneal collagen cross-linking to control further progression and was recommended to wear rigid gas-permeable contact lenses. CONCLUSIONS: Surgeons should be alert for cornea ectasia after refractive surgery in pregnant patients, as hormonal changes during pregnancy may affect corneal biomechanical stability.

Diagnosis and management of postrefractive surgery ectasia.

Postrefractive surgery ectasia is a serious, sight-threatening complication seen after the following procedures: laser in situ keratomileusis, photorefractive keratectomy, small-incision lenticule extraction, radial keratotomy, and/or arcuate keratotomy. Specific risk factors may include age, corneal thickness, degree of refractive error, corneal topographic changes including irregular astigmatism, percent tissue ablation, and residual stromal bed. Biomarkers may be a new option to help indicate who is at greatest risk for ectasia. Visual aids including spectacles or contacts lenses are often required to achieve optimal vision. Collagen crosslinking is the only treatment believed to stop progression of ectasia and prevent keratoplasty. Other surgical options may include topography-guided phototherapeutic keratectomy and intrastromal corneal ring segments. Ultimately, an "ounce of prevention is a pound of cure," so careful preoperative screening and ultimately offering the safest and most effective treatments for patients is arguably the most important job of the refractive surgeon.

Vision Restoration: Cataract Surgery and Surgical Correction of Myopia, Hyperopia, and Presbyopia.

Cataract surgery is one of the most common surgical procedures performed in the United States. The decision to remove a cataract is determined by the patient's ability to perform activities of daily living, such as reading, driving, and watching television. Cataract surgery also offers the potential of spectacle independence with a wide array of premium intraocular lens options. In addition, with the continuing advances in ophthalmology, patients now also have the option of selecting between traditional approaches and femtosecond laser-assisted procedures. Cataract surgery continues to be an effective and ever-improving procedure for vision restoration.

Comparison of outcomes of laser refractive surgery (LRS) alone and LRS with laser asymmetric keratectomy in patients with myopia: A retrospective study.

ABSTRACT: To compare and analyze the postoperative 1-year outcomes of laser refractive surgery (LRS) alone vs LRS with laser asymmetric keratectomy (LAK), in patients with myopia, for preventing and resolving LRS complications.This retrospective study compared the preoperative and 1-year postoperative outcomes between the control and comparison groups using a sum of deviations in corneal thickness in 4 directions >80 µm. The control group included 41 patients with myopia (41 eyes) who underwent LRS. The comparison group included 33 patients (33 eyes) who received LAK-linked LRS. Age, spherical equivalent (SE), sphere, cylinder, uncorrected distance visual acuity (UDVA), pupil size, kappa angle, central corneal thickness, corneal irregularity in the 3.0 mm zone on Orbscan maps (SUM), distance between the maximum posterior elevation (best-fit-sphere) and the visual axis (DISTANCE), postoperative blurring scores, frequency of postoperative myopic regression, and efficiency index were compared.Preoperative age (P = .198), SE (P = .686), sphere (P = .562), cylinder (P = .883), UDVA (P = .139), pupil size (P = .162), kappa angle (P = .807), central corneal thickness (P = .738), corneal irregularity (P = .826), SUM (P = .774), and DISTANCE (P = .716) were similar between the 2 groups. The 1-year postoperative SE (P = .024), sphere (P = .022), corneal irregularity (P = .033), SUM (P = .000), DISTANCE (P = .04), blurring scores (P = .000), and frequency of postoperative myopic regression (P = .004) were significantly decreased in the comparison group compared to the control group. UDVA (P = .014) and the efficiency index (P = .035) were higher in the comparison group.LAK with LRS improved corneal symmetry by reducing the SUM and DISTANCE. UDVA and efficiency index were also improved and blurring and myopic regression were reduced postoperatively.

Exacerbation of Granular Corneal Dystrophy Type 2 After Small Incision Lenticule Extraction.

PURPOSE: To report the outcome of unilateral small incision lenticule extraction (SMILE) in a patient with granular corneal dystrophy type 2 (GCD2). METHODS: Slit-lamp photography and Fourier domain optical coherence tomography were used to document the clinical course and appearance of the corneas in a patient with genetically determined GCD2 who underwent unilateral SMILE in the right eye. RESULTS: Slit-lamp examination of a 23-year-old woman revealed 2 faint opacities at the surgical interface approximately 2 months after the SMILE procedure had been performed on her right eye. Nine and 3 typical GCD2 deposits located immediately beneath the Bowman layer were observed in the right and left corneas, respectively. Over time, the deposits at the interface increased in size, density, and number in the right eye. Fourier domain optical coherence tomography performed 33 months after the SMILE procedure revealed deposits at the SMILE interface that were distinct from those located immediately beneath the Bowman layer. The severity of disease exacerbation was less in this patient than what is typically observed in others who have undergone laser-assisted in situ keratomileusis or photorefractive keratectomy. CONCLUSIONS: SMILE is contraindicated in patients with GCD2, as are other corneal refractive surgical procedures. This case highlights the importance of genetic testing before the performance of refractive corneal procedures-especially for patients with corneal opacities on preoperative slit-lamp examination or a family history of corneal disease compatible with that of a corneal dystrophy.

Complications of small incision lenticule extraction.

The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.

Epithelial ingrowth following small incision lenticule extraction.

A 27-year-old female patient came for a routine postoperative check-up, with a history of bilateral ReLEx small incision lenticule extraction (SMILE) surgery done 1.5 years back. On examination, epithelial ingrowth was noticed in the left eye at 8-9'o'clock position. Topography showed excess flattening in the area of ingrowth. Anterior Segment OCT showed hyper-reflectivity and was measured to be at a depth of 120 microns from the corneal surface. As the ingrowth appeared non-progressive, with no involvement of the pupillary axis and no visual complaints, no active intervention was done. Nonetheless, treatment options available include mechanical scraping and Nd:YAG laser procedure.