Ocular surface changes following computer use in post-LASIK patients

PURPOSE

To assess the impact of computer use on the ocular surface of individuals after laser in situ keratomileusis (LASIK).

METHODS

The dry eye symptoms and ocular surface of 18 post-LASIK young individuals and 18 controls were evaluated before and after performing a 30-min task on a computer without (Visit 1) and with (Visit 2) initial instillation of artificial tears. Symptoms were assessed using the Ocular Surface Disease Index (OSDI), Symptom Assessment in Dry Eye questionnaire version two (SANDE II) and Computer Vision Syndrome Questionnaire (CVS-Q). The ocular surface was assessed by measuring corneal higher order aberrations, tear meniscus height (TMH), conjunctival redness, blink rate and incomplete blinking, lipid layer thickness (LLT) and non-invasive keratograph break-up time (NIKBUT).

RESULTS

SANDE II scores were >0 after the computer task in both groups (p ≤ 0.01). SANDE II and CVS-Q scores did not differ between LASIK and controls (p ≥ 0.43). Greater bulbar-temporal conjunctival redness, TMH and LLT and shorter NIKBUT were found after computer use in the LASIK group (p ≤ 0.04), whereas no changes were observed in the controls (p ≥ 0.20). Lower SANDE II and CVS-Q scores were reported at Visit 2 compared with Visit 1 in both groups (p ≤ 0.01). Likewise, no worsening of dry eye signs was observed at Visit 2 (p ≥ 0.11).

CONCLUSIONS

Ocular symptoms reported during computer use were comparable between the groups. However, a worsening of dry eye signs was mostly observed in post-LASIK individuals. The instillation of artificial tears was effective in preventing the effects of computer use on the ocular surface in post-LASIK patients.

Persistent Monkeypox-Associated Keratouveitis in a Post-LASIK Cornea: A Case Report With Flap Removal

PURPOSE

This study aimed to report a case of persistent keratouveitis associated with mpox virus infection in an immunocompetent patient with a history of laser-assisted in situ keratomileusis (LASIK), leading to the need for flap removal.

METHODS

A comprehensive literature review was conducted, and a detailed case report was presented.

RESULTS

A 44-year-old immunocompetent male patient with a history of LASIK and HIV infection presented with conjunctival and corneal lesions indicative of mpox infection. Despite initial topical treatment, the condition worsened, leading to severe epithelial and stromal keratitis with anterior chamber inflammation. Polymerase chain reaction testing confirmed the presence of mpox virus in conjunctival, corneal, and aqueous humor samples. The patient underwent various treatments, including tecovirimat, oral and topical corticosteroids, and topical trifluridine, and eventually flap removal with amniotic membrane application. Subsequent polymerase chain reaction testing of the aqueous humor yielded negative results, and the cornea gradually reepithelialized without inflammation. After 8 months, the patient's eye remained stable, with a central stromal scar.

CONCLUSIONS

This case highlights the rare occurrence of mpox-associated keratouveitis and emphasizes the challenges faced in its management. The successful outcome achieved through a combination of antiviral therapy, antiinflammatories, and surgical intervention underscores the importance of a multidisciplinary approach in managing such cases.

Unilateral Granular Type 2 Corneal Dystrophy With Exacerbation After LASIK

PURPOSE

The aim of this study was to report a case of unilateral granular corneal dystrophy type 2 (GCD2) with exacerbation after bilateral laser in situ keratomileusis (LASIK).

METHODS

Clinical evaluation, Scheimpflug imaging, anterior segment optical coherence tomography (AS-OCT), cytology, and genetic testing were used to confirm the diagnosis of unilateral GCD2 with exacerbation after bilateral LASIK. Detailed literature review for possible unilateral GCD2 presentations was performed.

RESULTS

A 54-year-old White woman presented with blurred vision in her left eye and a history of bilateral LASIK performed 8 years before. Examination revealed dense opacities in the left cornea only, which were confirmed to be confined to the LASIK interface and adjacent corneal stromal tissue, as determined by AS-OCT. The patient underwent flap lift, interface debris removal, and stromal bed phototherapeutic keratectomy. Cytological analysis showed eosinophilic corneal stromal deposits that stained with trichrome stain and were congophilic on Congo red stain. Genetic testing was positive for heterozygous GCD2 transforming growth factor β-induced gene ( TGFBI ), c.371G>A, p.R124H mutation. There were no opacities identifiable in the right eye on serial slit-lamp examination, Scheimpflug imaging, or OCT imaging at 4 or 8 years after bilateral LASIK. Literature review failed to identify any previous reports of unilateral GCD2.

CONCLUSIONS

This is the first known reported case of unilateral granular corneal dystrophy type 2. LASIK is contraindicated in eyes with corneal stromal dystrophies related to mutations in TGFBI as both flap creation and laser ablation can exacerbate visually significant opacity formation. Scheimpflug and AS-OCT imaging are useful to identify opacities in GCD2.

Factors Predicting Loss of Best-Corrected Visual Acuity After Hyperopic Laser-Assisted In Situ Keratomileusis

PURPOSE

The aim of this study was to identify risk factors for the loss of corrected distance visual acuity (CDVA) after uncomplicated hyperopic laser-assisted in situ keratomileusis (LASIK).

METHODS

A retrospective study including hyperopic patients who underwent microkeratome-assisted LASIK between January 2000 and December 2019 at Care-Vision Laser Centers, Tel-Aviv, Israel. Loss of CDVA was defined as ≥ 2 lines (0.20 logarithm of the minimum angle of resolution [logMAR] increase). Excluded were patients who had loss of CDVA because of intraoperative or postoperative complications or developed cataract at their final visit.

RESULTS

Overall, 1998 eyes of 1998 patients were included in the study, of which 35 eyes (1.75%) had CDVA loss at final follow-up (mean 387 days). The vision-loss group had a significantly greater spherical treatment (3.4 vs. 2.8 D, P = 0.02), ablation depth (69.4 vs. 53.8 μm, P = 0.01), a higher proportion of treatments with a smaller optic zone (6.0 mm) (31.4% vs. 13.4%, P = 0.002), treatment with the EX200 (Alcon) excimer rather than the EX500 (Alcon) (74.3% vs. 39.0%, P < 0.001), and treatment with the Moria M2-90 microkeratome rather than the Moria Sub-Bowman's keratomileusis (SBK) microkeratome (65.7% vs. 29.6%, P < 0.001). In multivariate binary logistic regression, factors that remained significant predictors of CDVA loss were a greater spherical treatment (per 1 D treatment, odds ratio = 1.42, 95% CI, 1.11-1.81, P = 0.004) and the use of the Moria M2-90 microkeratome (odds ratio = 4.66, 95% CI, 2.30-9.45, P < 0.001).

CONCLUSIONS

In patients undergoing uncomplicated hyperopic LASIK, a greater spherical hyperopic treatment is associated with a higher risk for vision loss. Transition to a newer microkeratome model significantly reduced vision loss rate.

Tomographic Predictors of Ectasia Development After Keratorefractive Surgery

PURPOSE

The aim of this study was to identify the risk factors for postkeratorefractive surgery ectasia in unsuspicious tomographies and to report a new index coined diameter of peak locations (DPLs).

METHODS

All patients who underwent keratorefractive surgery between 2011 and 2018 at Care-Vision Laser Centers, Israel, and later developed ectasia were included. For each ectasia case, 3 matched controls were selected. Demographic and preoperative, intraoperative, and postoperative data were collected. Multivariate analysis was performed to evaluate the interdependence of the variables.

RESULTS

The retrospective study included 19 ectasia and 58 control eyes. There were no significant differences between the groups in ablation depth ( P = 0.73), preoperative spherical equivalent ( P = 0.12), percent tissue altered ( P = 0.71), residual stromal bed ( P = 0.73), and Ectasia Risk Score System ( P = 0.60). The anterior and the posterior symmetry index were significantly higher ( P < 0.001), and DPL was significantly tighter in the ectasia group ( P = 0.01). Binary multiple logistic regression found the symmetry index of the posterior cornea and DPL to be better predictors than age, percent tissue altered, Ectasia Risk Score System, residual stromal bed, and ablation depth.

CONCLUSIONS

A higher posterior symmetry index and a tighter DPL are predictors of ectasia in patients with otherwise normal tomographies. A tight DPL implies a weak area in the cornea, which is thin and slightly bulging, increasing the risk of this area becoming ectatic.

Visual rehabilitation after LASIK complication: flap amputation, topo-guided surgery, and phacoemulsification

We present a case of a patient complaining of monocular diplopia due to a decentered ablation after LASIK. The patient underwent a wavefront-guided retreatment, which resulted in an epithelial ingrowth complication. Additionally, the patient developed cataract, with cataract surgery requiring reliable biometric measurements. Therefore, we opted for corneal treatment and corneal surface regularization. Although we attempted to lift the flap and wash the interface initially, the procedure proved unsuccessful, thereby necessitating immediate flap amputation. Once the corneal surface was regularized in the seventh postoperative month, transepithelial photorefractive keratectomy was successfully performed to homogenize the ocular surface, thereby significantly improving the patient's corrected visual acuity and resolving monocular diplopia. The surface and corneal curvature stabilized by the fifth month after the procedure. Phacoemulsification was then performed along with the implantation of a toric monofocal lens, which was selected using an appropriate formula, resulting in an excellent uncorrected visual acuity.

Femtosecond thin-flap laser assisted in situ keratomileusis for correction of post-penetrating keratoplasty ametropia: long-term outcome

PURPOSE

To evaluate the long-term clinical outcomes of femtosecond thin-flap LASIK (femto-LASIK) for correction of refractive error after penetrating keratoplasty in keratoconus-affected eyes.

SETTING

a private ophthalmology clinic.

DESIGN

Prospective interventional case series.

METHODS

This prospective interventional case series enrolled 22 eyes of 22 patients who underwent femto-LASIK for the management of post-penetrating keratoplasty ametropia. The refractive error, uncorrected (UDVA), and corrected (CDVA) distance visual acuities and vector analysis were reported in short-term and long-term period after surgery.

RESULTS

The mean age was 32.7 ± 7.5 years (range, 23 to 47 years) at the surgery time. The average time between PK and femto-LASIK was 42.5 ± 31.7 months. The average follow-up duration after femto-LASIK was 81.2 ± 18.6 months. The mean preoperative UDVA significantly improved from 0.47 ± 0.15 logMAR to 0.35 ± 0.14 logMAR at 12 months (P = 0.048) and 0.4 ± 0.17 at final follow-up exam (P = 0.007). CDVA was 0.22 ± 0.1 at baseline which improved to 0.18 ± 0.15 and 0.15 ± 0.1 logMAR at 12 and 81 months, respectively. (Ps = 0.027, 0.014). The mean cylinder before surgery was - 5.04 ± 1.4D which significantly decreased to -1.5 ± 0.8 D at 12 months postoperatively. (P < 0.001). There was a significant increase in refractive astigmatism from 12 months to 81 months postoperatively (-3.1 ± 2.0, P = 0.002). At the final visit, the efficacy index was 0.83, and the safety index was 1.16.

CONCLUSIONS

Despite the short-term outcome indicated that femo-LASIK was effective for correction of post-keratoplasty ametropia during short-term period, a notable regression in its effect was observed in the long-term follow-up. Therefore, the predictability of this technique might decrease in the long-term.

Clinical outcomes of SMILE and WFG-LASIK used to treat myopia and astigmatism: A systematic review and meta-analysis

PURPOSE

To evaluate the safety, efficacy and postoperative visual quality of small incision lenticule extraction (SMILE) and Wavefront-Guided Laser in situ keratomileusis (WFG-LASIK) and to analyze their efficacy in correcting astigmatism.

METHODS

A systematic literature search was performed using Cochrane Collaboration methodology. Databases searched included PubMed, Embase, the Cochrane Library and Web of Science. RevMan software version 5.3.0 was used for meta-analysis.

RESULTS

A total of 976 eyes were included in 8 studies, of which 539 eyes underwent SMILE and 437 eyes underwent WFG-LASIK. There were no statistically significant differences in the proportion of eyes achieving uncorrected distance visual acuity of 20/20 or better (P=0.18), the proportion of eyes within±0.50 diopter of target refraction postoperatively (P=0.10), or the postoperative magnitude of cylinder (P=0.10). Regarding the Alpins vector analysis of astigmatism, there was no statistically significant difference in the surgical magnitude of error (P=0.09) between the two groups. WFG-LASIK has a lower surgical angle of error (P= 0.002) and higher surgical correction index of cylinder (P=0.03) than SMILE. In terms of aberrations, higher order aberrations (P=0.46), spherical aberrations (P=0.22) and trefoil (P=0.56) were not statistically different, while WFG-LASIK induced less coma than SMILE surgery (P=0.02).

CONCLUSION

Both SMILE and WFG-LASIK are safe and effective ways to correct myopia and astigmatism. Compared with SMILE, WFG-LASIK has a lower surgical angle of error, higher surgical correction index of cylinder and induces less coma.

Use of nonsteroidal anti-inflammatory drugs in corneal epithelial ingrowth due to traumatic flap dislocation after LASIK: Case report

RATIONALE

Ophthalmologists mainly treat epithelial ingrowth by lifting the flap and scraping the ingrowth or using scraping combined with phototherapeutic keratectomy, mitomycin C, and so on. The potential usefulness of nonsteroidal anti-inflammatory drugs in such circumstances has not been reported before.

PATIENT CONCERNS

A 32-year-old man and a 25-year-old man underwent lifting and scraping of the flap and phototherapeutic keratectomy to remove the epithelial ingrowths. Unfortunately, the ingrowths recurred and continued to develop.

DIAGNOSIS

The patients were diagnosed with corneal epithelial ingrowth.

INTERVENTIONS

The administration of bromfenac sodium and fluorometholone eye drops.

OUTCOMES

Epithelial ingrowths in both patients disappeared after 6 and 1 month of treatment, respectively. There were no adverse reactions to the eye drops.

LESSONS

Nonsteroidal anti-inflammatory drugs may be broadly applied in the treatment of epithelial ingrowth after laser in situ keratomileusis.

Surgical outcomes of laser in situ keratomileusis (LASIK) in patients with stable systemic disease

PURPOSE

To evaluate the surgical outcome in terms of safety, efficacy, predictability, and retreatment rate of LASIK surgery in patients with controlled systemic diseases in comparison with healthy individuals.

METHODS

The retrospective study included data from 1936 eyes of 976 patients with stable systemic diseases who underwent LASIK surgery between January 2016 and June 2019. The safety, efficacy, predictability of the surgery, and retreatment rate were evaluated in comparison with a control group comprising 1951 patients. The study was approved by the local ethics committee and adhered to the principles of the Declaration of Helsinki. Statistical analysis was performed using R team and the level of statistical significance was set at p < 0.05.

RESULTS

All treatment groups demonstrated high safety and efficacy indices after LASIK surgery. Furthermore, the study arms demonstrated comparable predictability and retreatment rates to the control group in nearly all cases. Retreatment rates were significantly higher in the rheumatoid arthritis group (p = 0.03), while safety indices were significantly lower in the hay fever group compared to the control group (p = 0.004). No intra- or postoperative sight-threatening complications were documented.

CONCLUSION

Our findings suggest that selected patients with stable systemic conditions can safely undergo LASIK surgery and achieve comparable outcomes to healthy individuals. Further research is needed to better understand the treatment outcomes in this challenging patient population.

Characterization of postoperative LASIK ectasia features on higher-order aberration excimer ablation maps

BACKGROUND

To characterize anterior corneal higher-order aberration (HOA) excimer ablation map patterns in postoperative LASIK ectasia (POE) and to examine correlations between newly identified corneal HOA ablation map features of POE and known topographic indices.

METHODS

Prospective multicenter non-interventional descriptive study. A total of 28 eyes from 22 POE patients were enrolled. The postoperative HOA ablation map was derived from Topolyzer Vario corneal imaging at the time of POE diagnosis. Features that recurred were identified and then analyzed. Correlations to Orbscan indices were studied.

RESULTS

An arrangement of two elliptical paracentral ablation islands, deep inferior and shallow superior, in direct mirror-like opposition to each other, were identified on all HOA maps. The paracentral islands were accompanied by peripheral ablation crescents. The deep paracentral inferior island 'hot spot' coincided with the topographical apical POE cone and was highly reproducible in angular position (249.3 ± 17.3°). There was significant variation in ablation depth (shallow superior island: 11.5 ± 6.9 μm and deep inferior island: 32.5 ± 18.8 μm). The superior crescents had high variability in depth (34.8 ± 18.9 μm). Strong correlations were found between the corneal irregularity index and the ablation depth difference between the deep and shallow paracentral islands (R = 0.96; P < 0.0001).

CONCLUSION

The corneal HOA excimer ablation map revealed a recurring, distinct, easily recognizable pattern in POE eyes. Validated Orbscan POE indices and HOA ablation map islands showed a strong correlation. It is possible to extract useful information from the corneal HOA ablation map, potentially making it suitable for diagnosing and monitoring POE although more studies are needed.

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.

Interface Fluid Syndrome After Descemet Membrane Endothelial Keratoplasty in Patients With History of LASIK

PURPOSE

The aim of this study was to evaluate the visual, pachymetric, tomographic, and biomicroscopic findings in a series of cases with laser in situ keratomileusis (LASIK) flap interface fluid syndrome (IFS) after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Six cases were included in this study; all patients had a history of LASIK and underwent DMEK for the treatment of bullous keratopathy. After uneventful surgery, all patients presented with corneal edema and IFS under the LASIK flap, which was demonstrated with anterior segment optical coherence tomography (AS-OCT). Visual acuity, clinical findings, pachymetry, endothelial cell count, and AS-OCT were documented during the management of these cases.

RESULTS

IFS appears 2.33 days (±1.03) after DMEK. One case improved with conservative treatment. In 5 cases, the LASIK flap was lifted, the fluid was drained, and the flap was replaced. The mean best-corrected visual acuity after fluid drainage was 0.44 logMAR (range 0.18-1.0) and mean central corneal thickness was 538 μm ± 160. Total resolution of the IFS was achieved at 14.5 days (range 4-30) after DMEK. AS-OCT showed resolution of the flap interface in 5 of 6 cases, while 1 patient required second DMEK due to reaccumulation of the interface fluid.

CONCLUSIONS

IFS can occur after DMEK in patients with previous LASIK. AS-OCT is a valuable tool for monitoring these cases preoperatively and postoperatively. Early surgical management is often needed to achieve resolution.

Development of interface haze after femtosecond laser-assisted in situ keratomileusis with accelerated corneal crosslinking: a case series

BACKGROUND

Femtosecond laser-assisted in situ keratomileusis (FS-LASIK) with accelerated corneal crosslinking (FS-LASIK Xtra) is a recent procedure to achieve safer corneal ablation in myopic patients with borderline corneal thickness. Despite its well-accepted effectiveness, the development of remarkable interface haze is a potential concern but has rarely been reported and discussed.

METHODS

We report for the first time a case series of 11 eyes of 7 patients who developed typical interface haze 1-3 months after FS-LASIK Xtra for the correction of myopia with astigmatism, with intensity grades ranging from 0.5 + to 3 + at the time of onset.

RESULTS

The preclinical spherical diopters of the 7 patients ranged from - 2.25 D to - 9.25 D and cylindrical diopters ranged from - 0.25 D to - 2.50 D. The haze tended to be self-limiting, and topical anti-inflammatory therapy was given to moderate and severe cases, who responded well to treatment.

CONCLUSIONS

The development of clinically significant interface haze is a relatively rare complication after FS-LASIK Xtra but tends to have a higher incidence and intensity compared to conventional stromal surgery such as FS-LASIK. Timely treatment and close follow-up are essential to patients undertaking FS-LASIK Xtra.

Effect of 3% Diquafosol Sodium on Dry Eye After Femtosecond Laser-Assisted In Situ Keratomileusis and Small Incision Lenticule Extraction Surgery in High-Myopic Eyes

PURPOSE

To evaluate the effect of 3% diquafosol sodium eye drop on dry eye after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) in high-myopic eyes.

METHODS

Eighty-one cases with high myopia (162 eyes) who received FS-LASIK or SMILE were divided into four groups by surgical design and tear film stability: D-FS-LASIK (5s

RESULTS

The D-SMILE group showed increase in BUT postoperatively (1m: P =0.006, 3m: P =0.004), whereas C-FS-LASIK (1m: P =0.012) and C-SMILE (1m: P =0.036) groups showed decrease in BUT. Higher ΔBUT were observed in D-FS-LASIK (1m: P =0.027) and D-SMILE (1m: P =0.001, 3m: P =0.012) postoperatively. The D-FS-LASIK group showed less decrease than C-FS-LASIK group in Schirmer I. The D-SMILE group showed increase in Schirmer I, whereas C-SMILE showed decrease in 3 months. ΔOSDI was lower in D-SMILE group than in C-SMILE group (1m: P =0.026, 3m: P =0.035). Fatigue was severer in D-SMILE group than in C-SMILE group preoperatively ( P =0.019), although there was no significant difference postoperatively. Objective scattering index (1m: P =0.002, 3m: P =0.021) and tear film objective scattering index (1m: P =0.005, 3m: P =0.010) were lower in D-FS-LASIK group than in C-FS-LASIK group postoperatively. The D-FS-LASIK group showed better VA20% ( P =0.036) and VA9% ( P =0.027) than the C-FS-LASIK group 1 month postoperatively.

CONCLUSIONS

3% Diquafosol sodium eye drop was effective for SMILE and FS-LASIK-related dry eye in high-myopic eyes. It is necessary to focus on perioperative anti-dry eye management and especially pay attention to the eyes with risk factors, including unstable tear film, high myopia, and FS-LASIK surgery.

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Key Words Collapse

MESH Headings

• Humans
• Keratomileusis, Laser In Situ/adverse effects
• Hyaluronic Acid/therapeutic use
• Myopia/etiology
• Dry Eye Syndromes/drug therapy
• Dry Eye Syndromes/etiology
• Dry Eye Syndromes/surgery
• Lasers, Excimer/therapeutic use
• Ophthalmic Solutions
• Corneal Stroma/surgery

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Grants

• No. Z201100005520043 Beijing Municipal Science and Technology Commission

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Affiliation(s)

Dengxin Gao Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
Xiaotong Lv
Fengju Zhang
Yanzheng Song
Yushan Xu

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Self-limited corneal ectasia in a post-LASIK eye after cataract surgery: A case report

INTRODUCTION

To present a case with a history of laser in situ keratomileusis (LASIK) developing central conic protrusion after phacoemulsification cataract surgery, which spontaneously resolved 5 months postoperatively.

PATIENT CONCERNS

A 55-year-old female who underwent myopic LASIK surgery 10 years ago presented to the clinic with bilateral cataracts and without ectasia. Following phacoemulsification cataract surgery and intraocular lens implantation in the right eye, the patient experienced a significant increase in spherical equivalent and corneal astigmatism.

DIAGNOSES

Based on a central conic protrusion on topography examination, surgically-induced corneal ectasia was diagnosed.

INTERVENTIONS

Topical lubricants, corticosteroids, and serial follow-up with corneal topography.

OUTCOMES

The corneal protrusion gradually resolved over a period of 5 months.

LESSONS

For post-LASIK patient who developed corneal protrusion following uneventful cataract surgery with a clear corneal incision, the clear corneal wound may have disrupted the biomechanical stability of the post-LASIK eye, compromising the peripheral stromal integrity. Additionally, postoperative inflammation could have contributed to corneal ectasia. Smaller clear corneal wounds or scleral tunnel entry during cataract surgery in post-LASIK eyes should be considered. Monitoring wound healing and using topical steroids can aid in achieving satisfactory outcomes and reducing the potential vision-threatening complications associated with corneal ectasia.

Epithelial Inoculation After Small-Incision Lenticule Extraction (SMILE): A Case Report

Epithelial ingrowth is a rare condition that is generally seen after laser in situ keratomileusis (LASIK) and has been reported in the literature in a small number of cases after small-incision lenticule extraction (SMILE) surgery. "Epithelial inoculation" should also be considered in patients presenting with decreased vision and an appearance similar to epithelial ingrowth in the early period after SMILE surgery. A 23-year-old woman presented to our clinic with a request for refractive surgery. Her manifest refractions were -7.50 -1.00 x 180° in the right eye and -7.25 -1.00 x 150° in the left eye, and best corrected distance visual acuity was 10/10 in both eyes. The SMILE procedure was performed with the Visumax femtosecond laser (Carl Zeiss Meditec AG). Slit-lamp examination at postoperative 1 week revealed a small grayish-white intrastromal opacity resembling epithelial ingrowth in the central optic axis of the right eye. Irrigation of the interface was performed with balanced salt solution using an irrigation cannula and the epithelial cluster was removed. The patient remained clinically stable 6 months after surgery and has experienced no recurrence. When epithelial inoculation is observed early after SMILE surgery, immediate irrigation of the interface appears to be an effective and safe treatment.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes

PURPOSE

Postoperative refraction in modern mi-croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes.

METHODS

Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed.

RESULTS

A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively).

CONCLUSIONS

Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

Management of traumatic displacement of LASIK flap

Background

Although flap-based laser refractive surgeries are being extensively performed worldwide, complications due to the flap may occur years after the procedure leading to severe vision-threatening complications.

Purpose

To describe the management of a case of traumatic displacement of a LASIK flap performed 8 years earlier.

Synopsis

A 42-year-old male presented to us with complaints of decreased vision in his left eye following trauma with a toy gun sustained a day earlier. His best-corrected visual acuity was Counting fingers @ 2 m, and a slit-lamp evaluation revealed a LASIK flap with its temporal edge folded inwards. Flap repositioning was planned. The final surgical plan was interface irrigation with mechanical debridement, alcohol epitheliectomy, fibrin glue application, and bandage contact lens. His uncorrected visual acuity improved to 6/6, N6 at 5 weeks postoperatively, which was maintained at 8 months postoperatively along with a clear interface.

Highlights

Traumatic displacement of LASIK flap years after the procedure is a known complication. However, simple flap repositioning may lead to various complications like epithelial ingrowth, DLK, astigmatism, etc., This video describes how to achieve anatomical and visual rehabilitation in such eyes without any long-term complications.

Video link

https://youtu.be/QtWG9hEMsXM.

Epithelial ingrowth under LASIK flaps: tips and tricks for preventing recurrence!

Background

LASIK for refractive error correction has become a universal surgery. Despite its popularity, the estimated prevalence of traumatic flap dislocations in post-LASIK patients is 3.9%, and it is sometimes associated with epithelial ingrowth. The prognosis in such cases depends on the rapid surgical revision of the flap with the removal of the EI and perioperative steps to prevent Epithelial ingrowth (EI) recurrence in the future.

Purpose

The video aims to display the steps involved in revising the flap, removing EI, and tips to prevent its recurrence.

Synopsis

A 33-year-old post-LASIK patient presented with decreased vision, photophobia, and glare during the COVID pandemic in the right eye for 2 months. The best-corrected visual acuity was reduced to 6/60. The anterior segment revealed traumatic flap dislocation along with macro fold temporally and epithelial ingrowth. She underwent a successful flap revision surgery with no recurrence of epithelial ingrowth postoperatively.

Highlights

A successful revision of a 2-month-old traumatic folded flap was performed along with the complete removal of EI. It explains the step-by-step approach to avoid the recurrence of EI in each step of the surgical revision of the flap. The video is self-explanatory and guides novice surgeons too.

Video link

https://youtu.be/JuOSjhrfw0g.

Mini-Review: Clinical Features and Management of Granular Corneal Dystrophy Type 2

Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant corneal stromal dystrophy that is caused by p.Arg124His mutation of transforming growth factor β induced (TGFBI) gene. It is characterized by well demarcated granular shaped opacities in central anterior stroma and as the disease progresses, extrusion of the deposits results in ocular pain due to corneal epithelial erosion. Also, diffuse corneal haze which appears late, causes decrease in visual acuity. The prevalence of GCD2 is high in East Asia including Korea. Homozygous patients show a severe phenotype from an early age, and the heterozygote phenotype varies among patients, depending on several types of compound heterozygous TGFBI mutations. In the initial stage, conservative treatments such as artificial tears, antibiotic eye drops, and bandage contact lenses are used to treat corneal erosion. Different surgical methods are used depending on the depth and extent of the stromal deposits. Phototherapeutic keratectomy removes anterior opacities and is advantageous in terms of its applicability and repeatability. For deeper lesions, deep anterior lamellar keratoplasty can be used as the endothelial layer is not always affected. Recurrence following these treatments are reported within a wide range of rates in different studies due to varying definition of recurrence and follow-up period. In patients who have undergone corneal laser vision-correction surgeries such as photorefractive keratectomy, LASEK, or LASIK including SMILE surgery, corneal opacity exacerbates rapidly with severe deterioration of visual acuity. Further investigations on new treatments of GCD2 are necessary.

Interface fluid syndrome after LASIK surgery: retrospective pooled analysis and systematic review

Interface fluid syndrome (IFS) is a complication associated with laser in situ keratomileusis (LASIK) surgery where a fluid pocket in the corneal stroma decreases visual acuity. A systematic review of IFS cases using PRISMA guidelines was performed yielding a total of 33 patients. 2 outcomes were selected for logistic regression analysis: final corrected distance visual acuity (CDVA) and need for surgical management. Results showed 33.3% of patients required surgery, 51.5% had their IFS resolve within 1 month or sooner, and 51.5% had final CDVA 20/25 or better. Higher presenting intraocular pressure (IOP) and duration of IFS ≤1 month was associated with higher odds of final CDVA 20/25 or better (adjusted odds ratio [aOR] 1.12, P = .04; aOR 7.71, P = .02, respectively). Endothelial cell dysfunction led to 17.55 greater odds for requiring surgical compared to medical management (aOR 0.36, P = .04). Presenting IOP and duration of IFS predicted final CDVA, while prior endothelial cell dysfunction predicted need for surgery.

Infectious Keratitis After Keratorefractive Surgery: Update and Review of the Literature

OBJECTIVES

To summarize the clinical manifestations, microbiological profile, treatment, and prognosis of corneal infections after different keratorefractive surgery.

METHODS

To obtain relevant studies, English-language databases, including PubMed, Ovid Embase, Web of Science, and CLNAHL, were searched from January 1979 to March 2022. The fundamentals of the literature, clinical characteristics, pathogens, and treatments were retrieved for each included article.

RESULTS

Eighty-four studies involving 306 infectious eyes were included in this review. Risk factors of potential infection included a history of blepharitis, contact lens usage, and contaminated surgical instruments. The mean onset time was 22.9±38.7 days (range: 1 day to 3 years). The most common organism isolated from infectious keratitis after keratorefractive surgery were Staphylococcus aureus , followed by Mycobacterium and coagulase-negative Staphylococcus . Most of the infections after refractive procedures were sensitive to medical treatment alone, and the ultimate best-corrected visual acuity after medical treatment was as follows: 20/20 or better in 82 cases (37.0%), 20/40 or better in 170 cases (76.5%), and worse than 20/40 in 52 cases (23.5%). Surgical interventions including flap lift, flap amputation, ring removal, and keratoplasty were performed in 120 eyes (44.5%).

CONCLUSIONS

Most infections after keratorefractive surgery occur within a week, whereas more than half of the cases after laser-assisted in situ keratomileusis happen after about a month. Gram-positive cocci and mycobacterium are the most common isolates. Infections after LASIK, intracorneal ring (ICR) implantation, and small incision lenticule extraction, which primarily occur between the cornea layers, require irrigation of the tunnels or pocket with antibiotics.

Impact of Topical Cyclosporine-A or Topical Chloroquine on Post-LASIK Ocular Surface Stability - A Randomized Controlled Trial

PURPOSE

To compare effect of topical cyclosporine-A 0.05% (CsA) and chloroquine phosphate 0.03% (CHQ) as an adjunct to standard therapy in maintaining post-laser assisted in situ keratomileusis (LASIK) ocular surface stability.

METHODS

Randomized controlled trial on 100 eyes undergoing femtosecond-LASIK randomized into three groups: 33 eyes in Group I (Standard Treatment group), 34 eyes in Group II (CsA group) and 33 eyes in Group III (CHQ group). Standard treatment included topical moxifloxacin, topical prednisolone and carboxymethyl cellulose. Group II received topical CsA 0.05% twice daily for three months and group III received topical CHQ 0.03% twice daily for three months in addition to standard treatment. Primary outcome measure was change in ocular surface disease index (OSDI) at 6 months. Secondary outcome measures were tear break up time (TBUT), Schirmer-I score, tear film osmolarity, tear film MMP-9 and visual acuity. Follow-up was performed at postoperative 1, 3 and 6 months.

RESULTS

At 6 months, OSDI score, MMP-9, tear osmolarity, TBUT and Schirmer score were significantly better in both CsA and CHQ groups as compared with controls (p < 0.001). OSDI, Tear osmolarity, TBUT, MMP-9 levels were comparable in CsA and CHQ group (p > 0.05). In CsA group, tear film MMP-9 levels at 6 months were comparable to preoperative baseline (p = 0.09). There was no significant change in the Schirmer score from baseline in the CsA group; in addition, the Schirmer score was significantly better than the CHQ group at 6 months (p = 0.02). Visual acuity was comparable in all three groups. Adverse effects including burning sensation, stinging, pain and redness were reported by ten patients (CsA group- 3, CHQ group-7; p = 0.28).

CONCLUSION

Both CsA and CHQ are useful adjuncts to standard therapy in maintaining ocular surface stability after refractive surgery. Cyclosporine A has more potent and sustained anti-inflammatory effect with less ocular irritative effects.

Laser in situ keratomileusis versus Artisan lens implantation in correcting ametropia after penetrating keratoplasty for keratoconus

PURPOSE

To compare the long-term safety and efficacy of laser in situ keratomileusis (LASIK) with Artisan phakic intraocular lens implantation to correct refractive errors after penetrating keratoplasty (PK) for keratoconus.

METHODS

This retrospective comparative interventional case series included a total of 33 consecutive keratoconus eyes that had previous PK and received subsequent LASIK (n = 16) or Artisan lens implantation (n = 17) were included in this study. Outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, and complications.

RESULTS

Postoperatively, the UDVA of ≥20/40 was achieved in none of the LASIK group compared to 62.5% of eyes in the Artisan group (P < 0.001); the respective values for CDVA of ≥20/40 were 87.5 and 94.1% (P = 0.51). Spherical equivalent refraction decreased from - 6.97 ± 1.50 D preoperatively to - 4.20 ± 2.05 D postoperatively in the LASIK group (P < 0.001) and from - 10.79 ± 2.15 D preoperatively to - 2.13 ± 1.23 D postoperatively in the Artisan group (P < 0.001). There was no significant change in the refractive astigmatism in LASIK group (P = 0.30) or Artisan group (P = 0.11). The efficacy and safety indices were significantly better for Artisan (0.82 ± 0.34 and 1.13 ± 0.30, respectively) than for LASIK (0.22 ± 0.17 and 0.85 ± 0.24, respectively, P ≤ 0.006 for both comparisons). While refractive error changed significantly from postoperative year 3 to the final visit in the LASIK group, it remained stable in the Artisan group through follow-up period. No significant complications were observed in any group.

CONCLUSION

Artisan lens implantation provided superior and stable visual outcomes compared to LASIK for the management of post PK refractive errors in keratoconus eyes.

Femto-LASIK after Deep Anterior Lamellar Keratoplasty to Correct Residual Astigmatism: A Long-Term Case Series Study

Purpose: To evaluate the long-term outcomes of femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) to correct residual astigmatism after deep anterior lamellar keratoplasty (DALK). Methods: This retrospective case series study included 10 eyes that underwent Femto-LASIK after a DALK. The refractive error, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, thinnest corneal thickness (TCT), and central corneal thickness (CCT) were registered. The postoperative follow-up ranged between 36 and 60 months. Results: All surgeries were uneventful, with no intra- or postoperative complications. The mean UDVA (Snellen scale) rose from 0.13 ± 0.05 to 0.47 ± 0.15 six months after Femto-LASIK (p < 0.001). All cases experienced a significant improvement in UDVA. None of the eyes lost lines of CDVA, and seven eyes (70%) improved the CDVA compared to preoperative values. The refractive cylinder changed from a preoperative value of −3.88 ± 1.00 D to −0.93 ± 0.39 six months after Femto-LASIK (p < 0.0001). In eight eyes (80%), the UDVA and refractive outcomes remained stable at postoperative follow-up visits. In contrast, one eye experienced a refractive regression over the follow-up. TCT and CCT were stable at the different postoperative follow-up visits. Conclusions: Our findings suggest that Femto-LASIK might safely and effectively corrects residual astigmatism after DALK. Despite these encouraging results, further long-term studies, including a larger number of cases, are required to confirm the safety of the procedure. The refractive stability in eyes with prior RK might be lower than for other DALK indications.

Efficacy and Safety of Surgically Managed Late Traumatic LASIK Flap Displacements in a Study of 66 Cases

PURPOSE

To evaluate safety and efficacy in the management of flap displacement after laser in situ keratomileusis (LASIK) and subsequent complications.

METHODS

This was a retrospective study performed using data recorded at the center's database from October 2002 to August 2021. Efficacy and safety were both converted to binary outcomes (loss of one or more lines and no change or gain in lines of visual acuity). The effects of time from surgery to complication and from complication to repair were assessed and the odds ratios and probabilities were calculated. The same procedure was applied to investigate the effect of these temporal variables on complications.

RESULTS

A total of 66 eyes with late traumatic LASIK flap displacements were studied. Efficacy remained unchanged in 48 patients (64 eyes, 75%), and safety remained unchanged in 53 patients (59 eyes, 90%). Sixty-six patients (64 eyes, 100%) achieved visual acuity values of 20/40 and 45 patients (64 eyes, 70.3%) achieved values of 20/20. The flap displacement was resolved in the first 24 hours (SD ± 0.1 days). Surgery was performed in 58 patients (65 eyes, 90%). Epithelial ingrowth was the most frequent complication. Patients who underwent surgery tended not to lose lines (P = .05). The risk of developing epithelial ingrowth increases with time after LASIK surgery until traumatic flap displacement (odds ratio: 1.001; P < .001). The prevalence of dislocation during the study period was 0.012%.

CONCLUSIONS

Visual safety values were favorable after resolution of the flap complication. Immediate surgical management leads to better visual efficacy, and the time between LASIK and trauma increases the risk of epithelial ingrowth after flap displacement. [J Refract Surg. 2022;38(4):270-276.].

Flap amputation for long-standing post-LASIK flap dislocation with epithelial ingrowth

A man aged 26 years presented with complaints of diminution of vision in his right eye for 1 year following a fist injury. He had a history of laser-assisted in situ keratomileusis in both eyes 5 years earlier. On examination, his uncorrected distance visual acuity (UDVA) in the right eye was 1.0 logMAR. Slit-lamp examination of the right eye revealed a superotemporal dislocation of the flap with coexisting epithelial ingrowth encroaching the pupillary area. Due to the presence of long-standing fixed flap folds, a flap amputation was performed along with removal of the epithelial ingrowth using 0.02% mitomycin C as adjunct. Postoperatively, the UDVA was 0.3 logMAR on day 1, which improved to 0.2 logMAR at 1 week. At 1 year, the UDVA was 0.2 logMAR improving to 0.1 logMAR with refraction, with minimal paracentral corneal haze and no signs of corneal ectasia.

Peripheral Hypertrophic Subepithelial Corneal Degeneration on a Laser-Assisted In Situ Keratomileusis Flap

ABSTRACT

We describe the first reported case of a patient developing peripheral hypertrophic subepithelial corneal degeneration (PHSCD) in the setting of previous femtosecond laser in situ keratomileusis (LASIK). Superficial keratectomy was performed successfully with the complete restoration of the visual acuity, no LASIK flap complications, and no recurrence of PHSCD at 1-year follow-up. Our case indicates that superficial keratectomy can be a safe and effective treatment for PHSCD in the setting of LASIK and raises awareness of the possibility of PHSCD developing in eyes that have undergone prior LASIK.

Prediction model of free flaps in microkeratome-assisted LASIK

Purpose

To identify mechanical factors, as well as patients’ biometric and surgeons’ experience factors that correlate with the FF incidence in microkeratome (MK)-assisted LASIK and to construct a predictive model based on these parameters.

Methods

55,700 consecutive LASIK treatments of 28,506 patients between January 2017 and April 2020 done by 50 surgeons in 10 centers, all with Sub Bowman Keratome (SBK) and 90μ head (OUP) were analyzed retrospectively for the incidence of FF and their correlation to mean keratometry, central corneal thickness, MK ring height and stop, as well as surgeons’ experience. A prediction model was built and tested for sensitivity and specificity.

Results

The incidence of FF using the SBK MK was 0.276%. Risk factors were low central corneal thickness, very flat (-1) or very thick (+2) ring height, and higher stop values (p<0.001). Mean keratometry and low surgeon experience were not correlated to FF incidence. A prediction model with a cut-off FF risk of 0.274%, a 76% specificity, and a 73% sensitivity was applied.

Conclusions

Free flaps are rarely seen in modern MK LASIK. However, the incidence of this complication using the SBK MK increases using higher stop values, very thick and very thin MK rings, and in eyes with thin corneas.

Five-Year Occurrence and Management of Central Toxic Keratopathy After Femtosecond Laser-Assisted LASIK

PURPOSE

To report the 5-year occurrence, management, and outcomes of 12 eyes diagnosed as having central toxic keratopathy (CTK) after femtosecond laser-assisted in situ keratomileusis (FS-LASIK).

METHODS

A retrospective chart review was conducted on 20,622 FS-LASIK procedures performed at a single site from January 2015 to December 2019 to identify patients diagnosed as having central toxic keratopathy. Preoperative and postoperative visual acuity, refraction, and imaging were recorded and analyzed.

RESULTS

CTK occurred in 12 eyes of 8 patients after FSLASIK. A total of 75% of eyes were diagnosed during an outbreak that happened over 2 months and the remaining 25% were considered sporadic. Five eyes were treated with flap lift and irrigation and 7 eyes were treated non-surgically. The average time to resolution of CTK in eyes that underwent flap lift and irrigation was 53 days compared to 33 days in eyes treated non-surgically. All 5 eyes treated with flap lift and irrigation ultimately achieved uncorrected distance visual acuity of 0.1 logMAR or better, whereas only 3 of 7 eyes treated non-surgically achieved the same. At the final postoperative visit, the eyes treated with flap lift and irrigation measured on average 14 µm thinner and 1.60 diopters (D) flatter than the expected postoperative pachymetry and keratometry, respectively. Those treated non-surgically were on average 28 µm thinner and 1.70 D flatter than expected.

CONCLUSIONS

CTK is a rare complication of FS-LASIK but can occur in clusters. Although management of CTK is debated, flap lift and irrigation may lead to better visual acuity and refractive and anatomic outcomes in some cases. [J Refract Surg. 2021;37(1):25-31.].

Corneal Refractive Surgery in the Right Patient at The Right Time

BACKGROUND

Despite their proven level of safety and patient satisfaction, laser-assisted in situ keratomileusis (LASIK) and other corneal refractive surgeries have faced scrutiny in the media recently as they have been linked to suicides following poor outcomes. Between 1998 and 2006, the Food and Drug Administration (FDA) received 140 official complaints linked to LASIK surgery, spurring the development of a Patient-Reported Outcomes With LASIK (PROWL) questionnaire to measure quality of life-related outcomes after LASIK. Dry eye symptoms are the most common complication after LASIK, but the overall patient satisfaction rate after surgery remains around 95 percent with around 1 million surgeries performed in the U.S. each year. Three cases involving completed or attempted suicide after corneal refractive surgery are discussed. Considerations and recommendations including preoperative screening and counseling to help prevent similar outcomes in the future are provided.

OBJECTIVE

We seek to discuss the facts surrounding LASIK surgery, and the factors that may contribute to a purported connection between corneal refractive surgery and mental illness.

CONCLUSION

Patients will continue to pursue refractive surgery with high expectations. Prevention by proper screening and setting of realistic expectations paired with early recognition and treatment may help minimize the effect of complications. Less-than-perfect cases must be reported to build a more robust body of literature on the topic. This will help highlight the procedures' safety and efficacy while improving management when complications occur. Performed for the right patient, at the right time, refractive surgery has the potential for consistently transformative results.

Complications of laser-assisted in situ keratomileusis

Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.

Scleral Lens Visual Rehabilitation of Sequential Bilateral Corneal Hydrops With Post-LASIK Ectasia

ABSTRACT

This case report describes a unique presentation of bilateral sequential acute corneal hydrops that manifested several years after laser in situ keratomileusis. Initial management included anterior chamber perfluoropropane gas injection and corneal suturing. Longer-term visual rehabilitation involved the use of scleral lenses which significantly reduced lower- and higher-order ocular aberrations.

Interface Fluid Syndrome 2 Decades After Laser-Assisted In situ Keratomileusis

PURPOSE

To report a case of late-onset interface fluid syndrome (IFS) after laser-assisted in situ keratomileusis (LASIK).

METHODS

A 94-year-old man was referred for evaluation because of persistent corneal edema 10 days after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) for pseudophakic bullous keratopathy.

RESULTS

After an uneventful DSAEK, the patient was treated with topical antibiotics and steroids. On presentation, a well positioned and oriented DSAEK graft was observed in the right eye, yet the cornea was edematous. Applanation tonometry was normal. Anterior-segment optical coherence tomography (AS-OCT) revealed a LASIK flap with a fluid cleft beneath it. Requery confirmed that LASIK was performed 21 years ago. Topical steroids were stopped, and after 2 weeks, the cornea was clear, and AS-OCT revealed complete resolution of the interface fluid.

CONCLUSIONS

Even decades later, IFS should be considered as a source of corneal edema in patients after LASIK. Monitoring these patients with AS-OCT is recommended.

Large interface particles from LASIK surgery

The presence of interface debris is commonly reported in patients having undergone LASIK refractive surgery. The patient described here had numerous large particles believed to be plastic and metal artefacts from the surgery at the level of the stroma/flap interface, along with a corneal scar consistent with a foreign body injury. The aetiology and possible sequelae of the particles and scar are discussed.

Delayed onset diffuse lamellar keratitis following enhancement LASIK surgery

BACKGROUND

Diffuse lamellar keratitis (DLK) is a relatively uncommon complication of the refractive procedure, laser-assisted in situ keratomileusis (LASIK). If detected and diagnosed in a timely fashion, it can be treated and should resolve with minimal sequelae. If untreated, or misdiagnosed and treated incorrectly, there may be loss of visual acuity. Optometrists should be familiar with this condition, its signs, symptoms and correct treatment protocol.

CASE HISTORY

A 58-year-old male Caucasian developed delayed onset diffuse lamellar keratitis, seemingly in the absence of an epithelial defect, 25 days following an enhancement LASIK procedure to his right eye. The DLK in this patient is delayed longer than typically reported in the literature. Subsequent management with topical steroids was complicated as the patient was a steroid responder and developed a markedly raised intraocular pressure that was managed with a topical anti-glaucoma agent. The diagnosis, pathogenesis and issues relevant to the treatment of this condition are discussed.

CONCLUSION

Optometrists, particularly those actively participating in the shared care of refractive surgery patients, must be familiar with diffuse lamellar keratitis so that diagnosis is not delayed. As the number of cases of refractive surgery in Australia increases, optometrists will encounter this condition more frequently.

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

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.

Clinical outcomes after small-incision lenticule extraction versus femtosecond laser-assisted LASIK for high myopia: A meta-analysis

AIM

To compare postoperative clinical outcomes of high myopia after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).

METHODS

From March 2018 to July 2020, PubMed, MEDLINE, Embase, the Cochrane Library, and several Chinese databases were comprehensively searched. The studies meeting the criteria were selected and included; the data were extracted by 2 independent authors. The clinical outcome parameters were analyzed with RevMan 5.3.

RESULTS

This meta-analysis included twelve studies involving 766 patients (1400 eyes: 748 receiving SMILE and 652 receiving FS-LASIK). Pooled results revealed no significant differences in the following outcomes: the logarithm of the mean angle of resolution (logMAR) of postoperative uncorrected distance visual acuity (weighted mean difference (WMD) = -0.01, 95% confidence interval (CI): -0.02 to 0.00, I2 = 0%, P = 0.07 at 1 mo; WMD = -0.00, 95% CI: -0.01 to 0.01, I2 = 0%, P = 0.83 at 3 mo; WMD = -0.00, 95% CI: -0.01 to 0.00, I2 = 32%, P = 0.33 in the long term), and the postoperative mean refractive spherical equivalent (WMD = -0.03, 95% CI: -0.09 to 0.03, I2 = 13%, P = 0.30). However, the SMILE group had significantly better postoperative corrected distance visual acuity (CDVA) than the FS-LASIK group (WMD = -0.04, 95% CI, -0.05 to -0.02, I2 = 0%, P<0.00001). In the long term, postoperative total higher-order aberration (WMD = -0.09, 95% CI: -0.10 to -0.07, I2 = 7%, P<0.00001) and postoperative spherical aberration (WMD = -0.15, 95% CI: -0.19 to -0.11, I2 = 29%, P<0.00001) were lower in the SMILE group than in the FS-LASIK group; a significant difference was also found in postoperative coma (WMD = -0.05, 95% CI: -0.06 to -0.03, I2 = 30%, P<0.00001).

CONCLUSION

For patients with high myopia, both SMILE and FS-LASIK are safe, efficacious and predictable. However, the SMILE group demonstrated advantages over the FS-LASIK group in terms of postoperative CDVA, while SMILE induced less aberration than FS-LASIK. It remains to be seen whether SMILE can provide better visual quality than FS-LASIK; further comparative studies focused on high myopia are necessary.

Diffuse lamellar keratitis after LASIK with low-energy femtosecond laser

PURPOSE

To evaluate the incidence, evolution, and prognosis of diffuse lamellar keratitis (DLK) in a large series of laser in situ keratomileusis (LASIK) with low-energy femtosecond laser.

SETTING

Private practice, Siena, Italy.

DESIGN

Retrospective, consecutive, noncomparative case series study.

METHODS

Single-use instruments, powder-free gloves, and no corneal marking were used. Flap was created by a low-energy femtosecond laser (Ziemer Z2 and Z4).

RESULTS

A total of 37 315 eyes of 19 602 patients were reviewed. DLK was observed in 236 eyes (0.63%) of 149 patients (0.76%). Grade 1 DLK was observed in 231 eyes of 142 patients, grade 2 in 1 eye: when treated with topical steroids, they had no visual consequences. Three patients had bilateral grade 3 to 4 DLK: one of them, with bilateral grade 3, despite flap lifting and irrigation worsened to stage 4 (central stroma thinning and flattening), partially recovered in 2 years, and underwent repeat femtosecond laser-assisted LASIK for hyperopic shift in 1 eye. In all the 5 eyes that developed grade 4 DLK, corneal thickness decreased until the first month and then partially recovered; mean final tissue loss at 1 to 2 years was 35 µm. Compensatory epithelial thickening was observed.

CONCLUSIONS

DLK after low-energy femtosecond laser-assisted LASIK is rare; severe DLK (stages 3 and 4) was found in only 6 eyes (0.016%). Flap lifting and irrigation might not prevent progression. Spontaneous reformation of stromal tissue and epithelial thickening improve visual acuity in the long term; residual hyperopic shift can be corrected by repeat femtosecond laser-assisted LASIK.

Use of presbyopia-correcting intraocular lenses in patients with prior corneal refractive surgery

PURPOSE OF REVIEW

Corneal refractive surgery has achieved spectacle-free vision for millions of patients, but this aging population is now developing cataracts. Many of these patients may wish to avoid reliance on glasses after cataract surgery. Presbyopia-correcting intraocular lenses (IOLs) offer a solution, but corneal changes after refractive surgery may compound higher order aberrations and dysphotopic symptoms associated with these IOLs. This review aims to discuss potential factors that could aid in determining suitable postkeratorefractive candidates for presbyopia-correcting IOLs.

RECENT FINDINGS

Studies investigating which preoperative measures influence outcomes are lacking. The few studies that have examined presbyopia-correcting IOLs in postkeratorefractive patients report that satisfactory outcomes are possible. However, recommendations for preoperative thresholds appear limited to expert opinion and studies involving virgin corneas.

SUMMARY

As the number of presbyopia-correcting IOLs and postkeratorefractive patients grows, continued investigation into relevant preoperative factors and appropriate IOLs is required to make evidence-based decisions. The current literature shows that with rigorous counseling and appropriate patient selection, presbyopia-correcting IOLs can provide postkeratorefractive patients with satisfactory results and spectacle independence. In addition, the development of postoperative modifiable IOLs may prove to be the preferred option.

State of corneal nerve fibers after laser-assisted in situ keratomileusis

PURPOSE

To assess the state of corneal nerve fibers (CNF) based on quantitative parameters after laser correction of myopia using LASIK.

MATERIAL AND METHODS

The study examined 141 eyes - 80 eyes with myopia and 61 emmetropic eyes. In 47 cases a microkeratome was used to form a corneal flap, and in 33 cases a femtosecond laser was used (LASIK and FemtoLASIK, respectively). Confocal microscopy was performed before, as well as 1, 3, and 6 months after correction. Objective analysis of CNF involved automatic calculation of the anisotropy (K_ΔL) and symmetry (K_sym) coefficients of CNF orientation in the Liner 1.2S software.

RESULTS

Lower values of K_ΔL were revealed in myopia as compared to emmetropia. Regardless of the method of flap formation, no CNF could be detected in the central cornea 1 month after myopia correction. In all cases after FemtoLASIK and in 2 cases after LASIK, CNF in the central cornea were first visualized after 3 months, and after 6 months CNF could be detected in all cases. At a similar observation time, CNF were visualized both after LASIK and after FemtoLASIK in the superior and inferior peripheral portions of the cornea. Analysis of long-term postoperative changes in K_ΔL and K_sym revealed a decrease in the former and an increase in the latter.

CONCLUSION

Evaluation of the state of CNF after corneal refractive correction should take into account the initial changes in CNF in myopia that are possibly associated with an increase in axial eye length. A more dynamic restoration of innervation was noted in cases where the flap was formed with the femtosecond laser, which may be explained by the fact that the mechanism of tissue separation when using this type of coherent radiation is gentler. Considering the changes in the quantitative indicators characterizing the state of CNF, the question of «completeness» of the restored CNF as a result of reinnervation remains open.

Prevention of infection after corneal refractive surgery: a French survey

PURPOSE

To report the French refractive surgeons' real-life practices for preventing infection after corneal refractive surgery (photorefractive keratotomy [PRK], laser in situ keratomileusis [LASIK], and small-incision lenticule extraction).

SETTING

France.

DESIGN

Anonymous practice survey.

METHODS

The questionnaire was sent in a single email invitation to 400 declared refractive surgeons. The following information was recorded between December 2019 and April 2020, before the coronavirus pandemic: demographics data, preoperative evaluation and preparation of the patient, surgical management, immediate and postoperative protocol, and infections reported after corneal refractive surgery.

RESULTS

Eighty-three of 400 surgeons (20.75%) responded to the questionnaire; 55 (66.0%) performed more than 50 corneal refractive surgeries a year, and 25 (30.1%) performed more than 200 procedures a year. Thirty-six (43.4%) surgeons wore 3 protective items, 37 (44.6%) 2, 5 (6.0%) 1, and 5 (6.0%) zero. Seventy-seven (92.8%) surgeons used povidone-iodine for skin area disinfection and 54 (65%) for conjunctival fornix disinfection. The contact time of povidone-iodine was less than 3 minutes for 71 (85.0%) surgeons. Twenty surgeons (24.1%) reported at least 1 postrefractive surgery infection. Twenty percent of surgeons who wore sterile gloves for PRK reported postoperative infections compared with 62.5% for those who did not (P = .008). These figures were, respectively, 8.7% and 66.7% for the use of sterile gloves during LASIK (P = .002); 8.9% of surgeons who wore surgical masks for LASIK reported postoperative infections compared with 50.0% for those who did not (P = .01).

CONCLUSIONS

Practices are variable among French refractive surgeons. Wearing a surgical mask and sterile gloves during corneal refractive surgery appears to be advisable.

Excimer laser programming of refractive astigmatism vs. anterior corneal astigmatism in the case of ocular residual astigmatism (ORA)

PURPOSE

To determine whether manifest refractive astigmatism (RA) or anterior corneal astigmatism (CA) is the best value for excimer laser programming in cases of ocular residual astigmatism (ORA).

PATIENTS AND METHODS

Patients who had undergone LASIK surgery with a disagreement between manifest refractive and corneal cylinder (ocular residual astigmatism ORA)>0.75 D were included retrospectively in this study. We calculated target induced astigmatism vector (TIA), surgically induced astigmatism vector (SIA), difference vector between the astigmatism correction programmed in the excimer laser and refractive astigmatism (DVRA), difference vector between the astigmatism correction programmed in the excimer laser and corneal astigmatism (DVCA) and difference vector between TIA and SIA (DV), by the Alpins method. Vectorial differences between DV and DVRA, and between DV and DVCA, were then calculated to determine whether RA or CA was closest to the ideal cylinder for laser programming.

RESULTS

Of a total of 104 eyes undergoing LASIK, 22 eyes of 12 patients (21.1%) had an ORA>0.75 D and were included. Mean ORA was 0.9±0.2 D and mean postoperative subjective cylinder was 0.45 D. The DV-DVRA difference vector was 0.57±0.2 D, and the DV-DVCA difference vector was 0.86±0.4 D (P=0.02). RA was closer than CA to the ideal astigmatism correction.

CONCLUSION

In cases of discrepancy between manifest astigmatism and corneal astigmatism, correction of manifest refractive astigmatism seems to give a better refractive result.