Dry eye disease after refractive surgery: comparative outcomes of small incision lenticule extraction versus LASIK

Femtosecond laser-assisted in situ keratomileusis versus small-incision lenticule extraction: current approach based on evidence

PURPOSE OF REVIEW

Laser keratorefractive surgery achieves excellent visual outcomes for refractive error correction. With femtosecond laser, small incision lenticule extraction (SMILE) is an increasingly viable alternative to laser-assisted in situ keratomileusis (LASIK). Comparative studies demonstrate similar efficacy and predictability between SMILE and LASIK, making it difficult for clinicians to choose which to use. This review thus compares femtosecond-LASIK (FS-LASK) and SMILE in various scenarios, to assist clinicians in deciding which refractive surgery procedure to recommend.

RECENT FINDINGS

SMILE may be superior for highly myopic eyes due to a smaller decrease in functional optical zone. SMILE further induces less spherical aberration and less overall higher order aberrations in mesopic conditions. SMIILE also has less postoperative dry eye, making it suitable those with preexisting dry eye. For low to moderate myopic astigmatism correction, FS-LASIK has less undercorrection compared to SMILE. Lastly, SMILE has not yet received Food and Drug Administration or Conformité Européenne approval for hyperopic correction, rendering FS-LASIK the choice of procedure for hyperopic correction.

SUMMARY

Both FS-LASIK and SMILE demonstrate good efficacy and predictability. Understanding specific clinical scenarios where one may be superior to the other will aid clinicians in choosing the most suitable procedure for personalized care.

The inferocentral whorl region and its directional patterns in the corneal sub-basal nerve plexus: A review

There has been a growing application of in vivo confocal microscopy (IVCM) in the examination of corneal microstructure, including different corneal layers and corneal nerve fibers in health and in pathological conditions. Corneal nerves forming the sub-basal nerve plexus (SBNP) beneath the corneal basal epithelial cell layer in particular have been intensively researched in health and disease as a marker for corneal neurophysioanatomical and degenerative changes. One intriguing feature in the SBNP that is found inferior to the corneal apex, is a whorl-like pattern (or vortex) of nerves, which represents an anatomical landmark. Evidence has indicated that the architecture of this 'whorl region' is dynamic, changing with time in healthy individuals but also in disease conditions such as in diabetic neuropathy and keratoconus. This review summarizes the known information regarding the characteristics and significance of the whorl region of nerves in the corneal SBNP, as a potential area of high relevance for future disease monitoring and diagnostics.

Impact of Topical 0.05% Cyclosporine A Eye Drops on Post-Femtosecond-Assisted Laser In Situ Keratomileusis Ocular Surface Recovery: A Randomized Clinical Trial

OBJECTIVES

To investigate the effect of topical 0.05% cyclosporine A (CsA) eye drops as an adjunct to conventional therapy in maintaining post-femtosecond-assisted laser in situ keratomileusis (FS-LASIK) ocular surface stability.

METHODS

Sixty-six patients (eyes) undergoing FS-LASIK were randomized into 2 groups: 33 patients (eyes) in group I (conventional treatment group) and 33 patients (eyes) in group II (CsA group). Conventional treatments include topical levofloxacin, fluorometholone, and artificial tears. Group II received topical 0.05% CsA eye drops twice daily for three months in addition to conventional treatment. Ocular Surface Disease Index (OSDI), numerical rating scale (NRS), tear break-up time (TBUT), Schirmer I test (SIt), corneal fluorescein staining (CFS), conjunctival lissamine green (LG) staining, corneal sensitivity, and corneal nerve morphology were measured. In addition, tear inflammatory cytokine levels were measured using the Luminex assay. Follow-up was performed preoperatively and 1 and 3 months postoperatively.

RESULTS

In the CsA group, OSDI, TBUT, LG, corneal sensitivity, and corneal nerve fiber total branch density recovered better than in the conventional treatment group. As for tear inflammatory cytokines, interferon (INF) -γ, interleukin (IL)-10, and IL-6 levels were significantly higher in the conventional treatment group as compared with the CsA group. In addition, no significant differences in NRS, SIt, and CFS scores were observed between the two groups.

CONCLUSION

In conclusion, 0.05% CsA eye drops is a useful adjunct to conventional treatment for restoring the ocular surface stability after corneal refractive surgery and is more potent in sustaining anti-inflammatory effects.

BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report provides an overview of the evidence for the treatment profile, safety, and efficacy of the range of corneal techniques currently available for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. Presbyopia correction by conductive keratoplasty involves application of radiofrequency energy to the mid-peripheral corneal stroma which leads to mid-peripheral corneal shrinkage, inducing central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Effects of Topical 0.05% Cyclosporine A on Dry Eye Symptoms and Parameters Following Small Incision Lenticule Extraction

PURPOSE

To evaluate the effects of topical 0.05% cyclosporine A on Ocular Surface Disease Index (OSDI) score and ocular surface parameters after small incision lenticule extraction (SMILE) for myopia.

METHODS

In this study, 151 patients who underwent SMILE were randomized into the control group (71 eyes) and the 0.05% cyclosporine A group (80 eyes). Both groups received standard treatment during the 1 month after SMILE. Over the next 3 months, The control group continued standard therapy (0.3% sodium hyaluronate) and the 0.05% cyclosporine A group received additional 0.05% cyclosporine A. OSDI total and subscale scores, non-invasive tear break-up time (NIBUT), tear lipid layer thickness (LLT), and tear meniscus height (TMH) were assessed preoperatively and postoperatively.

RESULTS

Compared to baseline, the OSDI scores significantly increased in both groups (P < .001). The 0.05% cyclosporine A group exhibited lower OSDI total scores after administering 0.05% cyclosporine A versus the control group (P = .026). At 1 month of follow-up, NIBUT, LLT, and TMH values significantly decreased in both groups compared to baseline (P < .05). The 0.05% cyclosporine A group exhibited higher NIBUT, LLT, and TMH versus the control group, returning to preoperative values after 2 months. Overall, the OSDI total score and NIBUT values during follow-up were not significantly different between the two groups; however, the LLT and TMH values were significantly different between the two groups (P < .001 and .041, respectively) by repeated measures analysis of variance.

CONCLUSIONS

Topical 0.05% cyclosporine A was effective in relieving subjective dry eye symptoms and maintaining ocular surface stability in the early postoperative period of SMILE. [J Refract Surg. 2024;40(4):e229-e238.].

Dry Eye Disease in the Middle East and Northern Africa: A Position Paper on the Current State and Unmet Needs

In the Middle East and Northern Africa (MENA), dry eye disease (DED) is often misdiagnosed or overlooked. This review summarizes a series of conversations with ophthalmologists in the region around a variety of climatic, lifestyle, and iatrogenic factors that contribute to specific features of DED in the MENA region. These considerations are further classified by patient lifestyle and surgical choices. All statements are based on discussions and formal voting to achieve consensus over three meetings. Overall, a deeper understanding of the disease characteristics of DED specific to MENA can better guide local eyecare practitioners on appropriate management and follow-up care. Additionally, population-based studies and patient and physician education on ocular surface diseases, together with the use of culturally appropriate and language-specific questionnaires can help ease the public health burden of DED in this region.

Analysis of Clinical Characteristics and Neuropeptides in Patients with Dry Eye with and without Chronic Ocular Pain after FS-LASIK

INTRODUCTION

Chronic ocular pain, particularly prevalent in patients with dry eye disease and post-femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) surgery, presents with unclear clinical characteristics and an undefined pathogenesis. In this study, we aimed to compare clinical characteristics and tear neuropeptide concentrations in patients with dry eye disease (DED) with and without chronic ocular pain following FS-LASIK, and investigate correlations between ocular pain, clinical characteristics, and tear neuropeptide levels.

METHODS

Thirty-eight post-FS-LASIK patients with DED were assigned to two groups: those with chronic ocular pain and those without chronic ocular pain. Dry eye, ocular pain, and mental health-related parameters were evaluated using specific questionnaires and tests. The morphology of corneal nerves and dendritic cells (DCs) was evaluated by in vivo confocal microscopy. Function of corneal innervation was evaluated by corneal sensitivity. Concentrations of tear cytokines (interleukin [IL]-6, IL-23, IL-17A, and interferon-γ) and neuropeptides (α-melanocyte-stimulating hormone, neurotensin, β-endorphin, oxytocin, and substance P [SP]) were measured using the Luminex assay.

RESULTS

Most patients with chronic ocular pain experienced mild to moderate pain; the most common types included stimulated pain (provoked by wind and light), burning pain, and pressure sensation. More severe dry eye (P < 0.001), anxiety symptoms (P = 0.026), lower Schirmer I test values (P = 0.035), lower corneal nerve density (P = 0.043), and more activated DCs (P = 0.041) were observed in patients with ocular pain. Tear concentrations of SP and oxytocin were significantly higher in patients with ocular pain (P = 0.001, P = 0.021, respectively). Furthermore, significant correlations were observed among ocular pain severity, SP, and anxiety levels.

CONCLUSIONS

Patients with DED after FS-LASIK who have chronic ocular pain show more severe ocular and psychological discomfort and higher tear levels of neuropeptides. Furthermore, ocular pain severity is correlated with tear SP levels.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05600985.

Meta-analysis of efficacy, safety, stability and predictability of Small Incision Lenticule Extraction (SMILE) for myopia

In order to investigate the postoperative efficacy, safety, stability, and predictability of SMILE surgery as a treatment for myopia, a comprehensive search was conducted in April 2023 across prominent databases, including PubMed, EMBASE, Web of Science, and Cochrane Library. The search aimed to select relevant studies of randomized controlled trials (RCTs) comparing clinical outcomes between SMILE and other corneal refractive surgeries for myopia. Upon conducting the initial search, a total of 324 records were retrieved from the aforementioned databases. These records were subjected to a meticulous selection process, adhering to predetermined inclusion criteria, resulting in 17 studies being ultimately included for analysis. By pooling the results of these studies, the comparison between SMILE surgery and alternative corneal refractive surgeries demonstrated similar outcomes in terms of efficacy, safety, stability, predictability, and higher-order aberrations (HOAs) concerning the correction of myopia. Furthermore, it was observed that the SMILE procedure exhibited a lesser impact on corneal sensation and corneal nerve density compared to other corneal refractive surgeries. Based on these findings, SMILE surgery may be considered as a treatment option with a slight superiority over conventional corneal surgery for myopia.

Efficacy of topical 0.05% cyclosporine A and 0.1% sodium hyaluronate in post-refractive surgery chronic dry eye patients with ocular pain

BACKGROUND

The management of post-refractive surgery dry eye disease (DED) can be challenging in clinical practice, and patients usually show an incomplete response to traditional artificial tears, especially when it is complicated with ocular pain. Therefore, we aim to investigate the efficacy of combined topical 0.05% cyclosporine A and 0.1% sodium hyaluronate treatment in post-refractive surgery DED patients with ocular pain unresponsive to traditional artificial tears.

METHODS

We enrolled 30 patients with post-refractive surgery DED with ocular pain who were unresponsive to traditional artificial tears. Topical 0.05% cyclosporine A and 0.1% sodium hyaluronate were used for 3 months. They were evaluated at baseline and 1 and 3 months for dry eye and ocular pain symptoms and objective parameters, including Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory modified for the Eye (NPSI-Eye), tear break-up time (TBUT), Schirmer I test (SIt), corneal fluorescein staining (CFS), corneal sensitivity, and corneal nerve morphology. In addition, tear levels of inflammatory cytokines and neuropeptides were measured using the Luminex assay.

RESULTS

After 3 months of treatment, patients showed a statistically significant improvement in the ocular surface disease index (OSDI), TBUT, SIt, CFS, and corneal sensitivity (all P < 0.01) using linear mixed models. As for ocular pain parameters, the NRS and NPSI-Eye scores were significantly reduced (both P < 0.05) and positively correlated with the OSDI and CFS scores. Additionally, tear IL-1β, IL-6, and TNF-α levels were improved better than pre-treatment (P = 0.01, 0.03, 0.02, respectively).

CONCLUSION

In patients with post-refractive surgery DED with ocular pain, combined topical 0.05% cyclosporine A and 0.1% sodium hyaluronate treatment improved tear film stability, dry eye discomfort, and ocular pain, effectively controlling ocular inflammation.

TRIAL REGISTRATION

Registration number: NCT06043908.

Changes of dry eye parameters after small incision lenticule extraction surgery in patients with different ocular surface disease index scores

To evaluate the changes of dry eye parameters after small incision lenticule extraction (SMILE) surgery in patients with different ocular surface disease index (OSDI) scores. Prospective research. Participants were divided into two groups: Group A, OSDI < 13; and Group B, OSDI ≥ 13. The OSDI scores, tear meniscus height (TMH), first non-invasive tear film break-up time (NIBUT-First), and meibomian gland loss (MGL, %) were recorded at postoperative 1 -week and 1-month.113 eyes (57 patients) were enrolled, 70 eyes in Group A, and 43 eyes in Group B. In Group A, the OSDI scores significantly increased at 1-week and 1-month postoperative (all P < 0.001); the TMH, NIBUT-First and lipid layer grade significantly decreased at postoperative 1-week (P = 0.003, 0.005, 0.007, 0.004, respectively), but returned to preoperative level at 1-month postoperative. In Group B, only the lipid layer grade significantly decreased at postoperative 1-week (P < 0.05). Patients with different preoperative OSDI scores may experience different changes early after SMILE surgery. Patients with OSDI scores < 13 may experience more dramatic changes in dry eye symptoms which would resolve, while subjective complains could still exists at 1 month after surgery.

Cataract surgery after corneal refractive surgery: preoperative considerations and management

PURPOSE OF REVIEW

Corneal refractive surgery (CRS) is one of the most popular eye procedures, with more than 40 million cases performed globally. As CRS-treated patients age and develop cataract, the number of cases that require additional preoperative considerations and management will increase around the world. Thus, we provide an up-to-date, concise overview of the considerations and outcomes of cataract surgery in eyes with previous CRS, including surface ablation, laser in-situ keratomileusis (LASIK), and small-incision lenticule extraction (SMILE).

RECENT FINDINGS

Challenges associated with accurate biometry in eyes with CRS have been mitigated recently through total keratometry, ray tracing, intraoperative aberrometry, and machine learning assisted intraocular lens (IOL) power calculation formulas to improve prediction. Emerging studies have highlighted the superior performance of ray tracing and/or total keratometry-based formulas for IOL power calculation in eyes with previous SMILE. Dry eye remains a common side effect after cataract surgery, especially in eyes with CRS, though the risk appears to be lower after SMILE than LASIK (in the short-term). Recent presbyopia-correcting IOL designs such as extended depth of focus (EDOF) IOLs may be suitable in carefully selected eyes with previous CRS.

SUMMARY

Ophthalmologists will increasingly face challenges associated with the surgical management of cataract in patients with prior CRS. Careful preoperative assessment of the ocular surface, appropriate use of IOL power calculation formulas, and strategies for presbyopia correction are key to achieve good clinical and refractive outcomes and patient satisfaction. Recent advances in CRS techniques, such as SMILE, may pose new challenges for such eyes in the future.

The Accuracy of Flap Thickness and Diameter in LASIK Using a Femtosecond Laser

Purpose

To evaluate the resultant thickness of the WaveLight FS200 (Alcon Vision, LLC) created LASIK flap compared to intended thickness at the surgical visit, using the WaveLight EX500 (Alcon Vision, LLC) pachymeter and the resultant flap diameter compared to intended diameter.

Methods

This single arm, prospective, single surgeon study assessed the accuracy of the intended flap thickness and diameter, after successful bilateral LASIK surgery. The WaveLight FS200 femtosecond laser was used to create all flaps with an intended thickness of 120 μm. Flap thickness was calculated by subtracting the stromal bed thickness after flap lift from the preoperative corneal thickness using the WaveLight EX500 on-board optical pachymeter. Flap diameter was determined using digital analysis.

Results

A total of 58 subjects (116 eyes) completed the study. The calculated mean flap thickness was 120.6 ± 9.0 μm (range 102 to 143 μm) using the EX500 pre- and post-flap pachymetry measurements. There was no statistically significant difference between the planned and achieved flap thickness (p > 0.05). The mean difference in flap diameter between planned and actual was 0.02 ± 0.05 mm. Corneal thickness measured by Pentacam at up to 2 months preoperatively versus EX500 just prior to surgery was similar, with EX500 measuring 2 μm less on average than the Pentacam.

Conclusion

The results suggest that the WaveLight FS200 laser is reliable for LASIK flap thickness and diameter and accurately created flaps at the intended thickness and the intended diameter.

Moisture chamber goggles for the treatment of postoperative dry eye in patients receiving SMILE and FS-LASIK surgery

BACKGROUND

The incidence of refractive surgery-related dry eye disease (DED) is rising due to the increasing popularity of corneal refractive surgery. The moisture chamber goggles (MCGs) have been shown to tear evaporation by increasing local humidity and minimizing airflow. The current study aims to evaluate the efficacy of moisture chamber goggles for refractive surgery-related DED.

METHODS

In this nonrandomized open-label controlled study, 78 participants (156 eyes) receiving refractive surgery were enrolled between July 2021 and April 2022, and sequentially allocated to MGC and control groups. 39 participants were allocated to the MGC groups, of which 53.8% received small-incision lenticule extraction (SMILE) and 46.2% received femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and were instructed to wear MCGs for the duration of 1 month postoperatively, in addition to the standard postoperative treatment received by the control groups (56.4% SMILE, 43.6% FS-LASIK). Participants underwent full ophthalmic examinations, including visual acuity, manifest refraction, DED evaluations, and higher-order aberrations (HOAs), both preoperatively and at routine follow-ups 1 day, 1 week, and 1 month after surgery. DED parameters included non-invasive tear film break-up time (NIBUT), tear meniscus height (TMH), conjunctival congestion, lipid layer thickness (LLT), and ocular surface disease index (OSDI) questionnaires. Student's t-test was used for comparisons between control and MCG groups, and between preoperative and postoperative parameters within groups.

RESULTS

Postoperative NIBUT decreased in both SMILE and FS-LASIK control groups 1 day after the surgery (SMILE, P = 0.001; FS-LASIK, P = 0.008), but not in the corresponding MCG groups (SMILE, P = 0.097; FS-LASIK, P = 0.331). TMH in the MCG group was significantly higher at 1 week (P = 0.039) and 1 month (P = 0.015) in SMILE, and 1 day (P = 0.003) in FS-LASIK groups. In FS-LASIK participants, significantly lower HOAs and coma levels in the MCG group were observed 1 day (total HOAs, P = 0.023; coma, P = 0.004) and 1 week (total HOAs, P = 0.010, coma, P = 0.004) after surgery. No consistent statistically significant intergroup difference was observed between MCG and control groups in conjunctival congestion, LLT, and OSDI.

CONCLUSIONS

MCGs effectively slowed tear evaporation, increased tear film stability, and improved HOAs in patients receiving SMILE and FS-LASIK surgeries. MCG is an effective adjuvant therapy in the comprehensive management of refractive surgery-related DED.

Anterior segment inflammation and its association with dry eye parameters following myopic SMILE and FS-LASIK

PURPOSE

To evaluate dry eye and anterior segment inflammation after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and investigate their association.

METHODS

This prospective and observational study included 96 eyes from 48 myopic patients. The evaluation was performed at baseline, postoperative day 1, week 1, month 1 and month 3. Outcome measures included anterior chamber flare, bulbar redness (BR), limbal redness (LR), ocular surface disease index (OSDI), tear meniscus height (TMH), the first and average noninvasive breakup time (NIBUT-1, NIBUT-a), fluorescein breakup time (FBUT), corneal fluorescein staining (CFS), and Schirmer I. Generalized estimating equations (GEEs) were applied to explore the correlation between flare and ocular surface parameters.

RESULTS

Flare increased significantly in both groups at day 1 and week 1 and then returned to baseline at month 1. In both groups, BR decreased on day 1 and then gradually increased towards the baseline. In FS-LASIK, LR was lower than baseline at day 1 and month 3. An increase in OSDI was found in the SMILE group on day 1, and in the FS-LASIK group at day 1 to month 1. NIBUT-1 and NIBUT-a decreased significantly on day 1 in both groups. At month 3, NIBUT-a did not return to baseline in FS-LASIK. CFS increased significantly at week 1 in both groups. All parameters were comparable between SMILE and FS-LASIK except for OSDI and NIBUT-a. Time and spherical equivalent showed a correlation with flare.

CONCLUSIONS

Both SMILE and FS-LASIK induced elevated anterior chamber flare and dry eye. However, flare might not be considered a factor determining perioperative dry eye.Key MessagesDry eye disease is common after corneal refractive surgery. Signs and symptoms of dry eye disease persist longer after FS-LASIK compared with SMILE.Both FS-LASIK and SMILE transiently disrupted blood-aqueous barrier integrity, leading to anterior segment inflammation.Anterior chamber flare might not be considered a factor explaining perioperative dry eye, other biomarkers remain for future exploration.

Short-Term Impact of Different Corneal Incision Positions on Postoperative Astigmatism and Visual Quality After SMILE Surgery

INTRODUCTION

This study aimed to evaluate the short-term impact of different incision positions on astigmatism and visual quality after small incision lenticule extraction (SMILE) surgery.

METHODS

This prospective study enrolled patients who decided to have SMILE to correct myopia. Patients were randomly allocated into three groups of different incision positions (group A, B, and C with incision position at 90°, 120°, and 150° respectively). Preoperative and postoperative visual acuity, spherical equivalent, and high-order aberrations (HOAs) were measured and compared among groups. Astigmatism was analyzed with the ASSORT Group Analysis Calculator based on the Alpins method.

RESULTS

A total of 148 eyes were included for analysis (48 eyes in group A, 50 eyes in group B, and 50 eyes in group C). At 1 month postoperatively, the mean uncorrected distance visual acuity (UDVA) logMAR in group A, B, and C was - 0.03, - 0.03, and - 0.04, respectively. The mean corrected distance visual acuity (CDVA) logMAR in group A, B, and C was - 0.03, - 0.04, and - 0.04, respectively (P > 0.05). The mean postoperative spherical equivalent (SE) values were - 0.01 ± 0.38, - 0.07 ± 0.39, and - 0.16 ± 0.49 (D) in group A, B, and C, respectively (P > 0.05). There was no statistically significant difference in preoperative and postoperative magnitude of astigmatism among different groups (P > 0.05). Significant differences were found in the distribution of astigmatism axis among the three groups at 1 day (P = 0.02) and 1 week (P = 0.02) postoperatively. However, such differences were no longer significant at 1 month after surgery (P > 0.05). No significant differences were found in HOAs among different groups 1 month after surgery (P > 0.05).

CONCLUSION

Different incision positions have no effect on postoperative astigmatism and visual quality 1 month after SMILE surgery, though differences were found in the distribution of the astigmatism axis within 1 week after the surgery.

Delayed presentation of surgically induced scleral necrosis after I-BRITE procedure treated with immunosuppressive therapy

Surgically induced scleral necrosis (SISN) is an uncommon complication of ocular procedures. Cosmetic eye-whitening surgery involves conjunctival and Tenon's capsule dissection, cautery, and mitomycin C application. We report the case of a 36-year-old white woman referred to our clinic for severe pain, scleral inflammation, and necrosis in both eyes 9 years after I-BRITE, an elective eye-whitening procedure. An extensive workup yielded negative results. The patient improved with aggressive lubrication and topical and high-dose systemic prednisone (60 mg), with recurrence upon steroid tapering. Concomitant weekly methotrexate was added, resulting in inflammatory control and allowing discontinuance of topical and oral steroids.

Clinical Characteristics and Tear Film Biomarkers in Patients With Chronic Dry Eye Disease After Femtosecond Laser-Assisted Laser in Situ Keratomileusis

PURPOSE

To investigate clinical characteristics and tear film biomarkers of patients with chronic dry eye disease (DED) following femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).

METHODS

Patients were divided into the chronic DED after FS-LASIK (n = 36), DED without FS-LASIK (n = 39), and normal control (without FS-LASIK; n = 34) groups. Dry eye, pain, and psychological-related symptoms were evaluated using the Ocular Surface Disease Index (OSDI), Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory Modified for the Eye (NPSI-Eye), and Hamilton Anxiety Rating Scale (HAMA) questionnaires. Ocular surface parameters, tear cytokines, and neuropeptide concentrations were evaluated with specific tests.

RESULTS

The DED after FS-LASIK group showed higher corneal fluorescein staining scores, but lower OSDI and NPSI-Eye scores than the DED without FS-LASIK group (all P < .05). Corneal sensitivity and nerve density decreased in the DED after FS-LASIK group (all P < .01). Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-17A, IL-23, alpha-melanocyte stimulating hormone (α-MSH), oxytocin, and substance P levels were highest in the DED after FS-LASIK group, followed by the DED without FS-LASIK and normal control groups (all P < .05). Interferon-γ and neurotensin levels were only significantly higher in the DED after FS-LASIK group (all P < .05).

CONCLUSIONS

Patients with chronic DED after FS-LASIK showed milder ocular symptoms, greater epithelial damage, and higher levels of tear inflammatory cytokines and neuropeptides than patients with DED without FS-LASIK, indicating that the nervous and immune systems may play significant roles in FS-LASIK-related chronic DED development. [J Refract Surg. 2023;39(8):556-563.].

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Dry Eye Disease following LASIK, PRK, and LASEK: An Observational Cross-Sectional Study

Dry eye disease is the most frequent non-refractive postoperative complication following refractive surgery. This prospective study investigated the development of dry eye disease after three common refractive laser surgeries: laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and laser-assisted sub-epithelial keratectomy (LASEK). Patients who underwent uneventful refractive surgery in a single private medical center between May 2017 and September 2020 were included. Ocular surface disease was graded according to the Dry Eye Workshop severity (DEWS) classification. Patients were examined 6 months following refractive surgery. The analysis included 251 eyes of 137 patients: 64 eyes (36 patients) after LASEK, 90 eyes (48 patients) after PRK, and 97 eyes (53 patients) after LASIK. At 6 months post-surgery, the DEWS score was higher for the LASIK than the PRK and LASEK groups (p = 0.01). For the total cohort, severe DEWS score (grades 3 and 4) at 6 months post-surgery was correlated with female gender (p = 0.01) and to the amount of refractive correction (p < 0.001), but not to age (p = 0.87). In conclusion, LASIK surgery and female gender were associated with dry eye. Patients, particularly those with high myopia, should be counseled about the risk of developing dry eye after refractive surgeries.

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.

Top 50 most-cited articles on SMILE surgery between 2010 and 2022: a correlation comparison between conventional bibliometrics and current altmetrics of research impact

PURPOSE

To conduct a bibliometric and altmetric analysis of the top 50 most-cited articles on small incision lenticule extraction (SMILE) surgery and assess its correlations with other metrics.

METHODS

The terms "small incision lenticule extraction" or "SMILE" were searched in the title, abstract, and keywords using Web of Science database. The retrieved articles (n = 927, between 2010 and 2022) were analyzed in-depth using altmetric attention scores (AAS), and traditional metrics (citation numbers of articles, impact factor of journals, and other citation-based metrics). A correlation statistics was performed with metrics. The articles' focus was examined quantitatively and the most prolific parameters were identified. Authorship network and country statistics also was examined.

RESULTS

Citation numbers were between 491 and 45. AASs were between 26 and 0. The altmetric score correlated moderately with citation number (r = 0.44, P = 0.001) and annual mean citations (r = 0.49, P < 0.001), but correlated weakly with impact factor (r = 0.28, P = 0.045), and immediacy index (r = 0.32, P = 0.022). The most articles published from China and the most articles were published in 2014. Modern SMILE surgery was mostly compared to the older LASIK procedure. The highest authorship number of links belonged to Zhou XT.

CONCLUSION

The first bibliometric and altmetric analysis of SMILE research provides novel directions for future work by showing the current research trends, prolific parameters, and zones with potential for the public's attention, providing useful information about the dissemination of scientific knowledge on SMILE in social media and to the general public.

Patient-Reported Outcomes With Wavefront-Guided Laser in Situ Keratomileusis (PROWL) Study Outcomes From a Single Institution

PURPOSE

To determine patient-reported outcomes after laser in situ keratomileusis (LASIK) using wavefront-guided technology at a single institution.

METHODS

In this prospective observational study, 62 participants underwent examination and questionnaire at baseline, 1 month, and 3 months after surgery. The questionnaire included questions from validated questionnaires and new items to assess patient satisfaction with current vision and LASIK surgery, and existence/degree of visual symptoms.

RESULTS

At month 1, patients reported an improvement in far vision (P = .01), activity limitations (P ≤ .001), and less worry about vision (P ≤ .001), as well as new visual symptoms, including halos (P ≤ .001) and double images (P = .03). At month 3, patients still noted an improvement in near vision (P = .05), far vision (P ≤ .001), activity limitation (P ≤ .001), and worry (P ≤ .001) along with halos (P = .05), double images (P = .01), and dry eye (P = .01). A total of 3.3% of patients at month 1 and 0% at month 3 had difficulty performing any activity due to symptoms, and 34.6% and 25.0% of patients reported decreased quality of life at months 1 and 3, respectively.

CONCLUSIONS

After LASIK, patients experience new visual symptoms. Patients have high rates of satisfaction overall but with some patients reporting a decrease in quality of life 1 month after surgery; quality of life improves by postoperative month 3, with 25% patients reporting a decrease in visual well-being after surgery. [J Refract Surg. 2023;39(3):198-204.].

Ocular pain after refractive surgery: interim analysis of frequency and risk factors

PURPOSE

To examine the frequency and risk factors for ocular pain after laser assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).

METHODS

Prospective study of individuals undergoing refractive surgery at two different centers. Participants rated their ocular pain on a 0 - 10 Numerical Rating Scale (NRS) pre-surgery and 1 day, 3 months, and 6 months post-surgery. A clinical examination focused on ocular surface health was performed 3- and 6-months post-surgery. Persistent ocular pain was defined as an NRS score ≥ 3 at both 3- and 6-months post-surgery (cases) and this group was compared to individuals with NRS scores <3 at both time points (controls).

RESULTS

109 individuals underwent refractive surgery (87% LASIK; 13% PRK) and were followed for 6 months after surgery. Mean age was 34±8 years (range 23 to 57); 62% self-identified as female, 81% as White, 33% as Hispanic. Eight (7%) individuals reported ocular pain (NRS ≥ 3) prior to surgery, with the frequency of ocular pain increasing after surgery to 23% (n=25) at 3 months and 24% (n=26) at 6 months. Twelve individuals (11%) reported an NRS ≥ 3 at both time points and comprised the persistent pain group. Factors that predicted persistent pain after surgery in a multivariable analysis were: (a) ocular pain pre-surgery (b) symptom report of depression prior to surgery (Patient Health Questionnaire-9: PHQ9: odds ratio (OR) 1.3, 95% confidence interval (CI) 1.1-1.6, p=0.01); (c) use of an oral anti-allergy medication pre-surgery (OR 13.6, 95% CI 2.1-89.3, p=0.007). (d) pain intensity day 1 after surgery (OR: 1.6, 95% CI 1.2-2.2, p=0.005); Ocular surface signs of tear dysfunction were not related to pain complaints. Most individuals (>90%) were completely or somewhat satisfied with their vision at 3 and 6 months.

CONCLUSIONS

Eleven percent of individuals reported persistent ocular pain after refractive surgery, with several pre- and peri-operative factors predicting pain after surgery.

Post-LASIK dry eye disease: A comprehensive review of management and current treatment options

Laser-assisted in situ keratomileusis (LASIK) is a unique corneal stromal laser ablation method that uses an excimer laser to reach beneath corneal dome-shaped tissues. In contrast, surface ablation methods, such as photorefractive keratectomy, include removing epithelium and cutting off the Bowman's layer and the stromal tissue of the anterior corneal surface. Dry eye disease (DED) is the most common complication after LASIK. DED is a typical multi-factor disorder of the tear function and ocular surface that occurs when the eyes fail to produce efficient or adequate volumes of tears to moisturize the eyes. DED influences quality of life and visual perception, as symptoms often interfere with daily activities such as reading, writing, or using video display monitors. Generally, DED brings about discomfort, symptoms of visual disturbance, focal or global tear film instability with possible harm to the ocular surface, the increased osmolarity of the tear film, and subacute inflammation of the ocular surface. Almost all patients develop a degree of dryness in the postoperative period. Detection of preoperative DED and committed examination and treatment in the preoperative period, and continuing treatments postoperatively lead to rapid healing, fewer complications, and improved visual outcomes. To improve patient comfort and surgical outcomes, early treatment is required. Therefore, in this study, we aim to comprehensively review studies on the management and current treatment options for post-LASIK DED.

The Impact of Corneal Epithelial Thickening and Inhomogeneity on Corneal Aberrations After Small Incision Lenticule Extraction

PURPOSE

To investigate the corneal epithelial remodeling profile after small incision lenticule extraction (SMILE), the correlated explanatory variables, and its potential impact on corneal higher order aberrations (HOAs).

METHODS

This single-center study prospectively evaluated 75 right eyes of 75 patients scheduled for SMILE. An anterior segment optical coherence tomography device was used to automatically obtain central 6-mm corneal epithelial thickness (ET), total corneal HOAs, and individual Zernike components before and after surgery. The ET inhomogeneity over the central 3- and 6-mm cornea was quantified with coefficient of variance (CV).

RESULTS

Both ET and CV significantly increased 1 month postoperatively (all P < .05). The stepwise multiple regression analysis showed that ET and CV were significantly correlated with preoperative ET and CV, respectively (all P < .01). The corrected spherical equivalent also significantly influenced ET and CV (all P < .01). Over the central 6-mm zone, the alterations of total corneal HOAs and individual Zernike components such as vertical coma (Z7) and spherical aberration (Z12, Z24) were significantly correlated with ET and CV (all P < .05).

CONCLUSIONS

The SMILE-induced epithelial remodeling involved both ET and ET inhomogeneity. The modulation was associated with preoperative and treatment parameters, and exerted a significant impact on corneal HOA alterations especially over the central 6-mm cornea. Together with the amount of correction and corneal curvature gradient change, preoperative assessment of ET and ET inhomogeneity might help predict postoperative epithelial remodeling. [J Refract Surg. 2023;39(1):23-32.].

Change Patterns in Corneal Intrinsic Aberrations and Nerve Density after Cataract Surgery in Patients with Dry Eye Disease

This study aimed to evaluate the change patterns in corneal intrinsic aberrations and nerve density after cataract surgery in dry eye disease. The preoperative, 1- and 3-month postoperative dry eye-related parameters were obtained by the Oculus keratograph and the ocular surface disease index questionnaire. The corneal intrinsic aberrations were measured using the Pentacam HR system. In vivo confocal microscopy was performed to observe the vortical and peripheral corneal nerves. An artificial intelligence technique run by the deep learning model generated the corneal nerve parameters. Corneal aberrations on the anterior and total corneal surfaces were significantly increased at 1 month compared with the baseline (p < 0.05) but gradually returned to the baseline by 3 months (p > 0.05). However, the change in posterior corneal aberration lasted up to 3 months (p < 0.05). There was a significant decrease in the corneal vortical nerve maximum length and average density after the operation (p < 0.05), and this damage lasted approximately 3 months. The corneal vortical nerve maximum length and average density were negatively correlated with the anterior corneal surface aberrations before and 1 month after the operation (correlation coefficients, CC = −0.26, −0.25, −0.28; all p < 0.05). Corneal vortex provided a unique site to observe long-term corneal nerve injury related to eye dryness. The continuous damage to the corneal vortical nerve may be due to the continuous dry eye state.

Twelve-year global publications on small incision lenticule extraction: A bibliometric analysis

Purpose

To analyze the development process of small incision lenticule extraction (SMILE) surgery in a 12-year period.

Methods

We conducted a literature search for SMILE research from 2011 to 2022 using the Science Citation Index Expanded (SCIE) of the Web of Science Core Collection (WoSCC). The VOS viewer, and CiteSpace software were used to perform the bibliometric analysis. Publication language, annual growth trend, countries/regions and institutions, journals, keywords, references, and citation bursts were analyzed.

Results

A total of 731 publications from 2011 to 2022 were retrieved. Annual publication records grew from two to more than 100 during this period. China had the highest number of publications (n = 326). Sixty-five keywords that appeared more than four times were classified into six clusters: femtosecond laser technology, dry eye, biomechanics, visual quality, complications, and hyperopia.

Conclusion

The number of literatures has been growing rapidly in the past 12 years. Our study provides a deep insight into publications on SMILE for researchers and clinicians with bibliometric analysis for the first time.

Neuroimmune crosstalk in the cornea: The role of immune cells in corneal nerve maintenance during homeostasis and inflammation

In the cornea, resident immune cells are in close proximity to sensory nerves, consistent with their important roles in the maintenance of nerves in both homeostasis and inflammation. Using in vivo confocal microscopy in humans, and ex vivo immunostaining and fluorescent reporter mice to visualize corneal sensory nerves and immune cells, remarkable progress has been made to advance our understanding of the physical and functional interactions between corneal nerves and immune cells. In this review, we summarize and discuss recent studies relating to corneal immune cells and sensory nerves, and their interactions in health and disease. In particular, we consider how disrupted corneal nerve axons can induce immune cell activity, including in dendritic cells, macrophages and other infiltrating cells, directly and/or indirectly by releasing neuropeptides such as substance P and calcitonin gene-related peptide. We summarize growing evidence that the role of corneal intraepithelial immune cells is likely different in corneal wound healing versus other inflammatory-dominated conditions. The role of different types of macrophages is also discussed, including how stromal macrophages with anti-inflammatory phenotypes communicate with corneal nerves to provide neuroprotection, while macrophages with pro-inflammatory phenotypes, along with other infiltrating cells including neutrophils and CD4⁺ T cells, can be inhibitory to corneal re-innervation. Finally, this review considers the bidirectional interactions between corneal immune cells and corneal nerves, and how leveraging this interaction could represent a potential therapeutic approach for corneal neuropathy.

Alterations in the ocular surface and tear film following keratoplasty

The purpose of this study was to evaluate any alterations in the tear film and ocular surface beyond the early postoperative period following penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). This cross-sectional, contralateral-eye study compared ocular surface and tear film parameters of eyes with a previous PK or DALK in one eye and no prior surgery in the contralateral eye. Overall, 14 (87.5%) participants underwent PK, and 2 (12.5%) underwent DALK using a mechanical dissection. The median time from surgery was 3.4 years (range 1.5 to 38.7 years). The indication for unilateral keratoplasty was keratoconus in 15 (94%) participants, and corneal scarring in 1 (6%) eye, secondary to microbial keratitis. Operated eyes exhibited poorer non-invasive tear film breakup time, lower corneal sensitivity, lower sub-basal nerve density and more severe fluorescein staining scores than unoperated fellow eyes (all Q < 0.05). There were no significant differences in tear film lipid layer quality, tear meniscus height, conjunctival hyperaemia, lissamine green staining score, or meibography grade between operated and fellow eyes (all Q ≥ 0.20). Higher corneal esthesiometry threshold (lower corneal sensitivity) was correlated with shorter non-invasive tear film breakup time (Spearman’s rho =  − 0.361, p = 0.04) and increased fluorescein staining score (Spearman’s rho = 0.417, p = 0.02). Keratoplasty can induce persistent changes in the ocular surface and tear film, including: increased fluorescein staining, decreased tear film breakup time, decreased corneal sub-basal nerve plexus density, and reduced corneal sensitivity.

Modulating the tachykinin: Role of substance P and neurokinin receptor expression in ocular surface disorders

Substance P (SP) is a tachykinin expressed by various cells in the nervous and immune systems. SP is predominantly released by neurons and exerts its biological and immunological effects through the neurokinin receptors, primarily the neurokinin-1 receptor (NK1R). SP is essential for maintaining ocular surface homeostasis, and its reduced levels in disorders like diabetic neuropathy disrupt the corneal tissue. It also plays an essential role in promoting corneal wound healing by promoting the migration of keratocytes. In this review, we briefly discuss the structure, expression, and function of SP and its principal receptor NK1R. In addition, SP induces pro-inflammatory effects through autocrine or paracrine action on the immune cells in various ocular surface pathologies, including dry eye disease, herpes simplex virus keratitis, and Pseudomonas keratitis. We provide an in-depth review of the pathogenic role of SP in various ocular surface diseases and several new approaches developed to counter the immune-mediated effects of SP either through modulating its production or blocking its target receptor.

Bibliometric study of refractive surgery and dry eye scientific literature

OBJECTIVE

Currently, refractive surgery is a safe and effective procedure, and considered as a risk for development of dry eye. The aim of study is to analyze the scientific publications in the field of ocular dryness secondary to refractive surgery through a bibliometric approach. The temporal period goes since 2001-2019, years in which first references appeared and search limited selection is done, respectively. The set of publications ranges from the first publication appeared in 2001, to the last one selected in 2019.

METHODS

A search of references was made through Scopus, using "refractive surgery" as main descriptor, and «dry eye» as secondary one; both descriptors were limited to those available in the chosen field for the title, abstract, and keywords. The most common indicators and bibliometric maps were applied for to the selected publications.

RESULTS

A total of 78 original articles were collected from the timeframe 2001-2019. According to the Price's law, the growth of literature production was linear turned out in a linear growth of literature production. The annual growth rate was 8.6% with a literature doubling time of 8.4 years. The Bradford core, preferred journals chosen by authors were 4 with offered four preferred journals by the authors, all of them with an impact factor >2. These were Ophthalmology, Investigative Ophthalmology & Visual Science, Journal of Glaucoma and British Journal of Ophthalmology. Regarding geographical distribution, the United States had the highest production.

CONCLUSIONS

The scientific production of dry eye after refractive surgery follows a linear growth. In this instance, postulates of the Price's growth law of science are not fulfilled. In addition, there is a high rate of transience. That may indicate low productivity or presence of researchers from other related subjects disciplines, who have published occasionally in this topic.

Corneal Sensitivity and Patient-Reported Dry Eye Symptoms in a Prospective Randomized Contralateral-Eye Trial Comparing LASIK and SMILE

PURPOSE

To prospectively compare corneal sensation and patient-reported symptoms of dry eye in individuals undergoing laser-assisted in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE).

DESIGN

Prospective randomized contralateral-eye clinical trial.

METHODS

80 eyes of 40 patients with myopia at Byers Eye Institute at Stanford University were randomized to receive wavefront-guided femtosecond LASIK in one eye and SMILE in the fellow eye. Cochet-Bonnet esthesiometry was performed to assess corneal sensitivity preoperatively and at the 1-month, 3-month, 6-month, and 12-month postoperative visits. Participants also completed questionnaires at each visit to determine the Ocular Surface Disease Index (OSDI).

RESULTS

Eyes that underwent LASIK compared to SMILE demonstrated more cornea denervation at the postoperative 1-month (mean 2.1 vs 3.6 cm, p < 0.001), 3-month (3.5 vs 5.4 cm, p < 0.001) and 6-month (4.7 vs 5.7 cm, p < 0.001) visits. At the 12-month visit, both groups had returned to baseline corneal sensitivity (5.9 vs 5.9 cm, p = 0.908). There was no difference in OSDI between the two groups at any visit. Mean OSDI improved from the preoperative to the postoperative 12-month visit in both LASIK (15.3 to 8.6, p = 0.020) and SMILE (15.1 to 9.5, p = 0.029) groups.

CONCLUSIONS

LASIK resulted in greater corneal denervation compared to SMILE in the early postoperative period, though this difference was no longer apparent after 12 months. Despite this, there was no difference in self-reported dry eye symptoms between the two groups. Patient-reported dry eye symptoms improved after both LASIK and SMILE procedures.

The Efficient Regeneration of Corneal Nerves via Tunable Transmembrane Signaling Channels Using a Transparent Graphene-Based Corneal Stimulation Electrode

The efficient regeneration of corneal nerves is of limited success in the field of ophthalmology. This work reports the use of a non-invasive electrical stimulation technique that uses a transparent graphene-based corneal stimulation electrode and that can achieve efficient regeneration of corneal nerves. The corneal stimulation electrode is prepared using electroactive nitrogen-containing conducting polymers such as polyaniline functionalized graphene (PAG). This composite can carry a high capacitive current. It can be used to tune transmembrane signaling pathways including calcium channels and the MAPK signaling pathway. Tuning can lead to the efficient regeneration of corneal damaged nerves after the surgery of laser in-situ keratomileusis (LASIK). The composite and its application reported have the potential to provide a new way to treat nerve-related injuries.

Prospective, Randomized Contralateral Eye Comparison of Wavefront-Guided Laser In Situ Keratomileusis and Small Incision Lenticule Extraction Refractive Surgeries

PURPOSE

Wavefront-guided laser in situ keratomileusis (WFG-LASIK) and small incision lenticule extraction (SMILE) are keratorefractive surgeries that can improve uncorrected visual acuity in myopic patients. Comparison of visual outcomes in myopic patients treated with LASIK and SMILE is needed.

DESIGN

Prospective, randomized contralateral eye-controlled trial.

METHODS

We performed a single-center prospective, randomized contralateral eye comparison of WFG-LASIK and SMILE (NCT03067077). Myopic patients with low levels of astigmatism were treated with WFG-LASIK in one eye and SMILE in the fellow eye from March 2017 to March 2021. Treatments were randomized by ocular dominance. WFG-LASIK and SMILE were performed. Postoperative evaluation at 1 day consisted of uncorrected distance visual acuity (UDVA), wavefront aberrometry, and a slit-lamp examination. On subsequent postoperative visits at 1 month, 3 months, 6 months, and 12 months, UDVA, manifest refraction, 5% and 25% low-contrast visual acuity, wavefront aberrometry, and slit-lamp examination were performed.

MAIN OUTCOME MEASURE

The primary outcome measure was UDVA at 12 months.

RESULTS

Eighty-eight eyes of 44 patients with myopia were enrolled in the study. Seventy-four eyes of 37 patients had successful treatments and completed 12 months of follow-up. At postoperative month 12, there were a significantly higher proportion of WFG-LASIK eyes that had ≥20/20 UDVA compared with SMILE eyes (94% vs 83%, P < .05). There was no difference between spherical equivalent between WFG-LASIK eyes and SMILE eyes (-0.17 ± 0.25 vs -0.29 ± 0.38, P > .05); there was no difference in higher order aberrations, including coma, trefoil, and spherical aberrations (P > 0.05); and there were a significantly higher proportion of WFG-LASIK eyes that had improved 5% and 25% low-contrast visual acuity compared with SMILE eyes (P < 0.05).

CONCLUSIONS

WFG-LASIK and SMILE both offered marked improvements in corrected distance visual acuity and excellent predictability in both eyes. Compared with SMILE, WFG-LASIK resulted in faster visual recovery, better low-contrast visual acuity, and greater gains in uncorrected visual acuity.

Influences of SMILE and FS-LASIK on Corneal Sub-basal Nerves: A Systematic Review and Network Meta-analysis

PURPOSE

To compare postoperative corneal sub-basal nerve density and number between small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK).

METHODS

A search was made in PubMed, EMBASE, and the Cochrane library for prospective comparative studies. The analysis was divided into two parts: network meta-analysis and traditional meta-analysis of the studies directly comparing two surgical groups. Stata 16 (Stata Corporation) and Rev-Man 5.4 (Cochrane) software were used to analyze the data.

RESULTS

Twelve studies (n = 775) were included. In the network meta-analysis, the SMILE group showed a significant increase compared with the FS-LASIK group in corneal nerve density at 1 month postoperatively (mean: 4.23; 95% CI: 0.06 to 8.39, P < .05), and in the number of corneal nerve trunks at 6 months postoperatively (mean: 13.25; 95% CI: 10.20 to 16.30, P < .05). In the traditional meta-analysis, the SMILE group showed significant improvement compared with the FS-LASIK group in corneal nerve density at 1 (weighted mean difference [WMD]: -2.05, 95% CI: -3.11 to -1.00, P < .05) and 3 (WMD: -0.90, 95% CI: -1.30 to -0.50, P < .05) months postoperatively, and in the number of corneal nerve trunks (WMD: -2.52, 95% CI: -4.91 to -0.14, P < .05) and corneal nerve branches (WMD: -2.80, 95% CI: -3.41 to -2.19, P < .05) at 1 month postoperatively.

CONCLUSIONS

The corneal nerve injury in the FS-LASIK group was worse than that in the SMILE group. The corneal nerve recovery in the SMILE group was better at 3 months postoperatively. However, there was no significant difference in corneal nerve density and number between the two groups at 6 months postoperatively. [J Refract Surg. 2022;38(4):277-284.].

Effects of wearing swimming goggles on non-invasive tear break-up time in a laboratory setting

PURPOSE

The use of swimming goggles (SG) has demonstrated to alter different ocular parameters, however, the impact of wearing SG on the tear film stability remain unknown. The main objective of this study was to determine the short-term effects of wearing SG on tear film surface quality break-up time (TFSQ-BUT).

METHODS

Twenty-eight young healthy adults (14 men and 14 women) wore a drilled SG, and TFSQ-BUT was measured before, during and after SG use. Dynamic-area high-speed videokeratoscopy was used for the non-invasive assessment of TFSQ-BUT.

RESULTS

TFSQ-BUT was significantly reduced while SG wear in comparison to the baseline measurement (4.8 ± 4.5 s vs. 8.8 ± 6.9 s; corrected p-value = 0.017, d = 0.57, mean difference = 4.0 [0.6, 7.3]; 45% reduction). Immediately after SG removal, TFSQ-BUT rapidly recovered baseline levels (8.2 ± 5.9 s vs. 8.8 ± 6.9 s; corrected p-value = 0.744). The impact of wearing SG on TFSQ-BUT were independent of the gender of the participants (p = 0.934).

CONCLUSION

The use of SG induces a TFSQ-BUT reduction, with these changes returning to baseline levels immediately after SG removal. These data may be of relevance for the management of dry eye patients, who need to avoid circumstances that exacerbate tear film instability. Nevertheless, these results must be interpreted with caution since the experiment did not entirely mimic real-life conditions (e.g., eye cup piece drilled, time of exposure, environmental conditions). Future studies should consider the inclusion of dry eye patients and older individual in order to explore the generalizability of these findings.

Evaluation of Wide Corneal Epithelial Remodeling after Small Incision Lenticule Extraction (SMILE) with Wide-Field Optical Coherence Tomography

Purpose

This study aims to assess the corneal epithelial remodeling within a 9 mm diameter zone induced by small incision lenticule extraction (SMILE) and evaluate its relationship with the refractive outcomes.

Methods

A total of 64 eyes of 64 patients were included. Wide-field optical coherence tomography (OCT) was used to measure the epithelial thickness (ET) across a 9 mm diameter area, preoperatively, and after one day, one week, one month, three months, and six months postoperatively. The ET changes were compared among the different time points and analyzed zones.

Results

The ET increases from one week to three months and stabilized from three months to six months. Compared to the preoperative values, the mean ET changes at six months in central (2 mm), paracentral (2-5 mm), mid-peripheral (5-7 mm), and peripheral (7-9 mm) zones were 4.37, 4.36, 1.61, and -1.59 μm, respectively. The correlation between the epithelial thickening and the amount of myopia correction was positive in central (P = 0.001) and paracentral zones (P < 0.001) and negative in peripheral zone (P = 0.006). The intended diameter of the optical zone was negatively related to epithelial hyperplasia in the central (P = 0.020) and paracentral zone (P = 0.006), and the correlation was positive in the mid-peripheral zone (P = 0.001). The epithelial thickening of central zone (P = 0.012) and the difference of mean ET between central and paracentral zone (P = 0.020) were negatively related to the spherical equivalent at six months.

Conclusion

An asymmetric lenticule-like pattern of epithelial remodeling occurred in 9 mm diameter cornea at six months after myopic SMILE. The epithelial remodeling may affect the refractive outcomes of SMILE.

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.

Sodium hyaluronate combined with rhEGF contributes to alleviate clinical symptoms and Inflammation in patients with Xerophthalmia after cataract surgery

Background

To determine the effect of sodium hyaluronate combined with recombinant human epidermal growth factor (rhEGF) on clinical symptoms and inflammation in patients with newly diagnosed xerophthalmia after cataract surgery.

Methods

A total of 106 patients who underwent cataract surgery and were newly diagnosed with xerophthalmia in our hospital between June 2018 and August 2019 were enrolled. Of these, 50 patients who were treated with sodium hyaluronate (0.1%) were assigned to the monotherapy group (MG) and the remaining 56 patients who were treated with sodium hyaluronate (0.1%) combined with rhEGF (20 μg/ml) were assigned to the combination group (CG). The 2 groups were compared based on ocular surface disease index (OSDI) score, break-up time (BUT), fluorescein corneal staining level, Schirmer I test (SI) level, clinical efficacy (disappearance of typical symptoms, including eyes drying, burning sensation, foreign body sensation, etc), and interleukin (IL)-1, IL-6, and tumor necrosis factor-α (TNF-α) levels. Spearman correlation analysis was conducted to analyze the relationship between IL-1, IL-6, TNF-α and clinical efficacy. In addition, receiver operating characteristic curves were drawn to analyze the predictive value of IL-1, IL-6, and TNF-α in efficacy on xerophthalmia. Results: After treatment, the CG showed reduced OSDI score compared with the MG. The CG showed increased BUT (s) and SI (mm) levels compared with MG. After treatment, the CG exhibited decreased levels of IL-1(ng/mL), IL-6 (ng/mL), and TNF-α (ng/mL) compared with the MG. Spearman correlation analysis revealed that IL-1, IL-6, and TNF-α were negatively correlated with clinical efficacy. The areas under the curves of IL-1, IL-6, and TNF-α were 0.801, 0.800, and 0.736 respectively.

Conclusions

Sodium hyaluronate combined with rhEGF is helpful to alleviate clinical symptoms and inflammation in patients with xerophthalmia undergoing cataract surgery.

Femtosecond Small Incision Lenticular Extraction in comparison to Femtosecond Laser In situ Keratomileusis Regarding Dry Eye Disease

 Abstract Objective: Comparison of femtosecond small incision lenticule extraction (FS-SMILE) versus Femtosecond laser Insitu keratomileusis (FS-LASIK) regarding dry eye disease (DED) and corneal sensitivity (CS) after those refractive surgeries. Methods: A comparative prospective study conducted for a period of 2 years; from March 2017 until February, 2019. Enrolled patients were diagnosed with myopia. Fifty patients (100 eyes) were scheduled for bilateral FS-SMILE and the other 50 patients (100 eyes) had been scheduled for bilateral FS-LASIK. Both groups were followed for six months after surgery. The age, gender, and preoperative refraction for both groups were matched. Complete evaluation of dry eye disease had been performed for the intervals of one week pre-operatively, one and six months postoperatively. The evaluation included history of symptoms according to scoring systems, investigations and clinical examination. Results: One month postoperatively and in both groups, there was significant DED (P < .01), although the incidence was lower in femtosecond SMILE group, overall severity score (0-4): 0.3 ± 0.3 (FS-SMILE) vs. 1.4 ± 0.9 (LASIK). One month postoperatively, CS was lower in FS- LASIK more than FS-SMILE eyes (2.3 ± 2.2 vs 3.6 ± 1.8, respectively, P < .01) and then return to not statistically significant sensitivities at six-month duration. DED was negatively correlated with CS (P < 0.01). Conclusions: The FS-LASIK surgery had a more pronounced effect on the CS and DED compared with FS-SMILE, with higher incidence of DED postrefractive surgery.

How Should Corneal Nerves be Incorporated Into the Diagnosis and Management of Dry Eye?

Purpose

a)Confocal microscopy and aethesiometry have allowed clinicians to assess the structural and functional integrity of corneal nerves in health and disease. This review summarizes literature on nerves in dry eye disease (DED) and discusses how this data can be applied to DED diagnosis and treatment.

Recent findings

b)Subjects with DED have a heterogenous symptom and sign profile along with variability in nerve structure and function. Most studies have reported lower nerve density and sensitivity in aqueous tear deficiency, while findings are more inconsistent for other DED subtypes. Examining nerve status, along with profiling symptoms and signs of disease, can help categorize subjects into disease phenotypes (structural and functional patterns) that exist under the umbrella of DED. This, in turn, can guide therapeutic decision-making.

Summary

c)Due to the heterogeneity in symptoms and signs of DED, corneal nerve evaluations can be valuable for categorizing individuals into disease sub-types and for guiding clinical decision making.

Implantable collamer lens versus small incision lenticule extraction for high myopia correction: A systematic review and meta-analysis

Purpose

To compare the efficacy, safety, predictability and visual quality between implantable collamer lens (ICL) implantation and small incision lenticule extraction (SMILE) for high myopia correction in adults.

Methods

A systematic review and meta-analysis was conducted. A comprehensive literature search was done based on databases including PubMed, Science Direct, Embase, and the Cochrane Central Register of Controlled Trials. The efficacy index, safety index, changes in Snellen lines of corrected distance visual acuity (CDVA), predictability (difference between post-operative and attempted spherical equivalent error, SER), incidence of halos, and change in higher-order aberrations (HOAs) were compared. Mean difference (MD) and 95% confidence interval (CI) was used to estimate continuous outcomes, risk ratio (RR) and 95%CI was used to estimate categorical outcomes.

Results

Five observational studies involving 555 eyes were included in this review. Studies’ sample sizes (eyes) ranged from 76 to 197. Subjects’ refraction ranged from -6 diopter (D) to -12D. Study duration of most researches were 6 months or 12 months. Compared to SMILE, ICL implantation showed better efficacy index (MD=0.09, 95%CI:0.01 to 0.16) and better safety index (MD=0.08, 95%CI: 0.00 to 0.16). Compared with SMILE, more ICL-treated eyes gained one or more Snellen lines of CDVA (RR=1.54, 95%CI:1.28 to 1.86), more gained two or more lines (RR=2.09, 95%CI:1.40 to 3.13), less lost one or more lines (RR=0.17, 95%CI:0.05 to 0.63). There was no difference in predictability between two treatments, RRs of predictability of within ±0.5D and ±1D were 1.13 (95%CI: 0.94 to 1.36) and 1.00 (95%CI: 0.98 to 1.02). Compared with SMILE, ICL implantation came with a higher risk of halos [RR=1.79, 95%CI: 1.48 to 2.16] and less increase in total HOAs (MD=-0.23, 95%CI: -0.42 to -0.03).

Conclusion

Compared with SMILE, ICL implantation showed a higher risk of halos, but equal performance on SER control, and better performance on efficacy index, safety index, CDVA improvement and HOAs control. Overall, ICL implantation might be a better choice for high myopia correction in adults.

Structural and functional alterations in corneal nerves following single-step transepithelial photorefractive keratectomy

PURPOSE

To evaluate the relationship between structural and functional changes of corneal subbasal nerves after single-step transepithelial photorefractive keratectomy (TransPRK).

SETTING

Tianjin Medical University Eye Hospital.

DESIGN

Prospective observational study.

METHODS

Fifty-one eligible candidates who underwent TransPRK for moderate myopia were recruited. The regeneration of corneal subbasal nerves were evaluated by In Vivo Confocal Microscopy (IVCM) prior to surgery at 1 week, 1, 3, 6, and 12 months postoperatively. Meanwhile, the corneal sensitivity was measured by Cochet-Bonnet esthesiometer. The number of complete and incomplete blinks were recorded by LipiView interferometer. A correlation analysis was performed between these variables.

RESULTS

IVCM revealed the density and length of corneal nerve decrease immediately, and do not return to preoperative levels by 12 months post-TransPRK (P<0.01). Mean corneal sensitivity was slightly lower compared with preoperative levels at 1 week after surgery(P=0.001), then increases to baseline preoperatively within 1 month after surgery. Mean total blink frequency and the partial blink rates had no significant change postoperatively(P=0.087). There was no direct correlation between postoperative recovery of corneal sensitivity, changes of blink and regeneration of sub-basal corneal nerve.

CONCLUSIONS

The significant and prolonged decrease in corneal subbasal nerve morphology was accompanied by only a slight and transient reduction in corneal sensitivity to mechanical stimuli within 1 month after TransPRK. The results demonstrated that the structural changes of subbasal nerves were not parallel to their function after TransPRK.

Effects of long-term soft contact lens wear on corneal epithelial thickness after small incision lenticule extraction

The present study investigated changes in corneal epithelial thickness after small incision lenticule extraction (SMILE) in patients with long-term preoperative soft contact lens (SCL) wear, the impact of SCL wear on the efficacy of surgical outcomes and the effects of long-term SCL wear on postoperative corneal aberrations. Patients were assigned to three groups according to the duration of SCL wear: Group A, the non-SCL-wearing group; group B, those with SCL wear ≤1 year; and group C, those with SCL wear >1 year. Epithelial thickness was recorded in nine zones by anterior segment optical coherence tomography across a 5-mm diameter before surgery and at 1 week, and 1, 3 and 6 months post-surgery. Corneal epithelial thickness and corneal aberrations among the three groups were compared, as well as the effects of changes in corneal epithelial thickness on postoperative visual acuity and manifest refraction. No significant differences were noted with regard to age or preoperative spherical equivalent among groups A (22 eyes), B (17 eyes) and C (18 eyes). Preoperative corneal epithelial thickness in the inferonasal, inferior and inferotemporal zones was thinner in group B compared with that in group A, and corneal epithelial thickness was thinner in all nine zones in group C compared with that in group A (P<0.05). At all follow-up time points, in the central, nasal, inferonasal, inferior, inferotemporal and temporal areas, the epithelial thickness was thinner in group C compared with that in group A (P<0.05). At 3 months postoperatively, the epithelial thickness was thinner in the inferonasal and inferior sectors in group C compared with that in group B (P<0.05), and at 6 months postoperatively, the epithelial thickness in the inferior region was thinner in group C compared with that in group B (P<0.05). There were no significant differences in visual acuity or manifest refraction among the three groups at all postoperative time points. The total higher-order aberrations were greater in group C compared with those in group A for all time points (P<0.05) and were greater in group C at 1 and 3 months postoperatively compared with those in group B (P<0.05). The spherical aberrations at 3 and 6 months postoperatively were greater in group C compared with those in group A (P<0.05). The coma aberrations were greater in group C compared with those in groups A and B for all time points (P<0.05). In conclusion, long-term SCL wear will result in corneal epithelial thinning, which does not impact visual acuity or manifest refraction after SMILE.

Assessment of the correlation of the tear breakup time with quality of vision and dry eye symptoms after SMILE surgery

Purpose

It is well reported that dry eye symptoms can increase after many refractive surgery procedures. This study aims to provide a clinical understanding of the correlation of fluorescein tear film breakup time (FTBUT) with quality of vision (QoV) and dry eye symptoms following small incision lenticule extraction surgery (SMILE).

Methods

Patients electing to have SMILE surgery were subdivided into 2 groups: Group 1 included short preoperative FTBUTs of 3 to 6 seconds (s); Group 2 included long FTBUTs of ≥ 8 s. Uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction, FTBUT, QoV and Ocular Surface Disease Index (OSDI) questionnaires were recorded 1 and 6 months postoperatively.

Results

Thirty-nine subjects were included in each group. There was no significant difference in visual outcomes between the 2 groups at both the 1- and 6-month postoperative assessments. FTBUT remained significantly lower in group 1. Oxford staining was initially higher for group 1 at 1 month (P = 0.007), but there was no significant difference at 6 months (P = 0.180). There was no significant difference in QoV or OSDI scores between the 2 groups at both postoperative visits.

Conclusions

Low preoperative FTBUT (3–6 s) does not appear to negatively affect postoperative visual outcomes or results in a greater likelihood of dry eye symptoms and poor ocular surface compared to eyes with a longer preoperative FTBUT. These results suggest that a low preoperative FTBUT does not necessarily increase the likelihood of poor visual acuity, dry eyes symptoms, or poor ocular surface outcomes following SMILE surgery.

The pattern of the inferocentral whorl region of the corneal subbasal nerve plexus is altered with age

PURPOSE

To describe the pattern of the nerves in the inferocentral whorl region of the human corneal subbasal nerve plexus (SBNP) in health and diseases known to affect the subbasal nerves.

METHODS

Laser-scanning in vivo confocal microscopy (IVCM) was used to image the SBNP bilaterally in 91 healthy subjects, 39 subjects with type 2 diabetes mellitus (T2DM), and 43 subjects with Parkinson's disease (PD). Whorl regions were classified according to nerve orientation relative to age and health/disease status.

RESULTS

Of 346 examined eyes, 300 (86.7%) had an identifiable whorl pattern. In healthy subjects, a clockwise nerve orientation of the whorl was most common (67.9%), followed by non-rotatory or 'seam' morphology (21.4%), and counterclockwise (10.7%). The clockwise orientation was more prevalent in healthy subjects than in T2DM or PD (P < 0.001). Healthy individuals below 50 years of age had a predominantly clockwise orientation (93.8%) which was reduced to 51.9% in those over 50 years (P < 0.001). Age but not disease status explained whorl orientation in T2DM and PD groups. Moreover, whorl orientation is bilaterally clockwise in the young, but adopts other orientations and becomes asymmetric across eyes with age. Finally, we report reflective 'dot-like' features confined to the whorl region of the subbasal plexus, sometimes appearing in close association with subbasal nerves and present in 84-93% of examined eyes regardless of disease status, eye or sex.

CONCLUSION

Subbasal nerves in the inferocentral whorl region are predominantly clockwise in young, healthy corneas. With aging and conditions of T2DM and PD, counterclockwise and non-rotatory configurations increase in prevalence, and bilateral symmetry is lost. Mechanisms regulating these changes warrant further investigation.

Prevalence of Tear Film Hyperosmolarity in 1150 patients presenting for refractive surgery assessment

PURPOSE

To present an analysis of tear film hyperosmolarity in a large, consecutive population and evaluate the correlation of ocular and systemic conditions with tear film osmolarity.

SETTING

Private practice Sydney, Australia.

DESIGN

Single-centre, retrospective, consecutive cohort.

METHOD

1404 patients (n=1357 standard, n=47 post-refractive) undergoing screening for laser refractive surgery from October 2017 to October 2020 were reviewed. Routine examination included tear film osmolarity (TFO) and Ocular Surface Disease Index questionnaire). TFO was conducted prior to further tests and patients refrained from topical eye drops minimum two hours before the appointment.

RESULTS

Mean highest TFO in the standard population was 299.12±11.94mOsm/L with 82.3% of eyes <308mOsm/L indicating normal tear film homeostasis. The mean inter-eye TFO difference was 8.17±8.60mOsm/L with 65.2% of eyes <=8mOsm/L. Mean highest TFO in the post-refractive subgroup was 299.72±11.00mOsm/L with a mean inter-eye difference of 9.02±6.92mOsm/L. Post-refractive surgery patients indicated higher mean OSDI values of 15.28±14.46 compared to the remainder of the population 9.69±10.56 (p=0.012). Significant correlation was demonstrated between TFO scores and OSDI normal classification in the standard population only (p=0.005, r=0.077). The use of contact lens correlated inversely with TFO and OSDI scores (p=0.000, r=-0.136 and p=0.000, r=-0.152 respectively).

CONCLUSION

Our study represents the largest available cohort of TFO scores in a standard population presenting for refractive surgery. We found that although the majority of patients can be expected to fall within normal ranges, a reasonable percentage will be diagnosed with tear hyperosmolarity and therefore at risk of dry eye disease.