Outcomes of complex Descemet Stripping Endothelial Keratoplasty performed by cornea fellows.

BACKGROUND: A major obstacle that academic institutions face is the steep learning curve for cornea fellows initially learning to perform Descemet Stripping Endothelial Keratoplasty (DSEK). The purpose of this study is to evaluate the outcomes of complex DSEK performed by cornea fellow supervised by an attending surgeon at an academic institution. METHODS: Patients who underwent a complex DSEK procedure performed by a cornea fellow during the years 2009-2013 were included. All the surgeries were supervised by the same cornea attending. All patients had a minimum follow-up of 6 months. Charts were reviewed for demographic data, intraoperative and postoperative complications and clinical outcomes. Corneal graft survival was calculated using the Kaplan-Meier analysis. RESULTS: Fifty-seven eyes of 55 patients (mean age 77.5 ± 8.5 years) were included in the study with a mean follow-up time of 16.4 ± 15.6 months. Previous graft failure, presence of a tube and history of trabeculectomy were the leading diagnoses to define the surgery as complex. No intraoperative complications occurred. In 21.1% of cases a corneal graft detachment was documented in the first postoperative day. Mean visual acuity improved from 1.06 LogMAR (20/230) preoperatively to 0.39 LogMAR (20/50, p < 0.001) by the sixth postoperative month and to 0.52 LogMAR (20/65, p < 0.001) at the last follow-up visit. Graft failure rate was 29.8%. Kaplan-Meier analysis found a 67.2% graft survival rate at 20 months. CONCLUSIONS: Complex DSEK can be performed successfully with an acceptable postoperative complication rate by cornea fellows during their training period when supervised by an experienced attending.

Comparison of graft survival following penetrating keratoplasty and Descemet's stripping endothelial keratoplasty in eyes with a glaucoma drainage device.

PURPOSE: To compare corneal graft survival rates after penetrating keratoplasty (PK) and Descemet's stripping endothelial keratoplasty (DSEK) in patients with a glaucoma drainage device (GDD) or medically managed glaucoma. METHODS: A retrospective chart review was conducted on consecutive patients who underwent primary PK or primary DSEK. Inclusion criteria consisted of eyes with a diagnosis of glaucoma prior to corneal transplantation and a minimum of 6 months of follow-up. Graft failure was defined as an edematous cornea with failure to maintain deturgescence lasting beyond a period of 1 month of intense steroid therapy or vascularization and scarring resulting in irreversible loss of central graft clarity. Corneal graft survival was calculated using Kaplan-Meier survival analysis. Patients were divided into four groups: GDD-PK, GDD-DSEK, medical-PK and medical-DSEK. RESULTS: Fifty-six eyes of 56 patients were identified as meeting inclusion criteria. Among eyes with a GDD, there was no difference in the proportion of failures between PK grafts (48%) and DSEK grafts (50%) (p = 0.90). Failure occurred earlier in DSEK recipients compared to PK recipients, 5.82 ± 6.77 months versus 14.40 ± 7.70 months, respectively (p = 0.04). A Kaplan-Meier analysis did not identify a difference between the four groups with respect to graft failure (p = 0.52). CONCLUSION: There is no significant difference in graft survival rates between medically and surgically treated glaucoma patients for either PK or DSEK grafts. In patients with GDD, graft failure occurs earlier in DSEK compared to PK.

Scheimpflug Corneal Densitometry Values and Severity of Guttae in Relation to Visual Acuity in Fuchs Endothelial Corneal Dystrophy.

PURPOSE: The purpose of this study was to investigate the association between corneal densitometry (CD) values from Scheimpflug tomography imaging, severity of guttae, and visual acuity in eyes with Fuchs endothelial corneal dystrophy (FECD). METHODS: This was a retrospective, cross-sectional study. Patients with FECD were examined at the Bascom Palmer Eye Institute from January 2015 to September 2019. We extracted CD values at central annuli of 0-2, 2-6, 6-10 and 10-12 mm from Scheimpflug tomography images. We investigated the association of corrected distance visual acuity (CDVA) with CD values, severity of guttae, central corneal thickness (CCT), cataract grade, refractive error, corneal edema grade, age, and gender using multivariate generalized estimating equation regression models. RESULTS: One hundred ninety-two eyes from 110 patients were included in this study. Increase in central CD values at the 0 to 2 mm zone (P < 0.001), severity of guttae (P = 0.046), age (P < 0.001), cataract grade (P < 0.001), corneal edema grade (P < 0.001), and type of refractive error (P = 0.008) were significantly associated with decreased CDVA. Central corneal thickness, sex, and the peripheral CD values (2-6, 6-10, and 10-12 mm) were not significantly associated with CDVA (P > 0.05) in the final multivariate regression model. CONCLUSIONS: Our study demonstrates that central CD values at 0 to 2 mm and severity of guttae are each associated with decreased CDVA in FECD. These findings carry implications for patients with FECD considering surgical intervention for phacoemulsification alone, Descemet stripping only, or endothelial cell transplantation and provide a multifactorial perspective on vision loss in FECD.

Considerations for Corneal Surgery With Patients in the 10th Decade of Life.

PURPOSE: The purpose of this study was to report the indications, ocular and systemic comorbidities, and surgical outcomes of corneal transplantation in patients older than 90 years. METHODS: A retrospective review was conducted to identify individuals 90 years and older who underwent corneal transplantation surgery at the Bascom Palmer Eye Institute between January 2013 and October 2020. Outcomes included best-corrected visual acuity and graft survival over time. Paired t tests were used to compare visual acuity preoperatively versus postoperatively. Graft survival was evaluated with Kaplan-Meier curves. RESULTS: Fifty-eight eyes of 52 consecutive individuals were included. The mean age of individuals was 92 ± 2 years; 26.9% were male; and 48.1% self-identified as non-Hispanic White and 38.5% as Hispanic. Postoperative follow-up was 14.7 ± 12.1 months. Of the 58 eyes, 44.8% (26/58) underwent penetrating keratoplasty, 46.6% (27/58) Descemet stripping automated endothelial keratoplasty, and 6.9% (4/58) keratoprosthesis. All surgeries were performed under monitored local anesthesia, without major complications. Surgical indications included pseudophakic bullous keratopathy (36.2%), glaucoma-associated corneal decompensation (27.6%), Fuchs endothelial dystrophy (25.9%), and perforated corneal ulceration (19.0%). The best-corrected visual acuity improved by 0.32 (95% confidence interval 0.14-0.50; P < 0.01) as early as 1 month postoperatively, and vision gains were sustained for at least 12 months. Graft survival probability at 12 months was 88%. CONCLUSIONS: Corneal transplantation is a safe and successful procedure in restoring the visual acuity for patients older than 90 years after careful preoperative evaluation. Further research is needed to evaluate the impact of corneal transplantation on quality of life in patients in the 10th decade of life.

Long-term results of femtosecond laser-assisted sutureless anterior lamellar keratoplasty.

PURPOSE: To evaluate the long-term results of femtosecond laser-assisted anterior lamellar keratoplasty (FALK) for anterior corneal pathologies. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Thirteen consecutive patients who underwent FALK for anterior corneal pathologies. INTERVENTION: Femtosecond laser-assisted sutureless anterior lamellar keratoplasty. MAIN OUTCOME MEASURES: Best spectacle-corrected visual acuity (BSCVA), manifest refraction, need for adjunctive surgery, and complications. RESULTS: Follow-up ranged from 12 to 69 months (mean = 31 months). The BSCVA was significantly improved over preoperative values at the 12-, 18-, 24-, and 36-month visits. A BSCVA greater than 20/30 was achieved in 54% of patients at the 12-month visit when all 13 patients were available for follow-up, in 50% and 33% of patients at the 18- and 24-month visits, respectively, when 12 patients were available, and in 60% and 50% of patients at the 36- and 48-month visits when 5 and 2 patients were available, respectively. The BSCVA of the eye that completed the 60- and 70-month visits was 20/50. Patients achieved a mean gain of 5 lines of BSCVA at the 6-, 12-, 18-, and 24-month visits, 4 lines at the 36-month visit, 5 lines at the 48-month visit, and 6 lines at the 60- and 72-month visits. Two patients lost a mean of 1.5 lines of BSCVA because surface haze developed after photorefractive keratectomy (PRK) and granular dystrophy recurred in the graft. At a mean of 5 weeks postoperatively, 83.3% of patients achieved BSCVA within 2 lines of that recorded at the 24-month visit. At the 12-month visit, mean spherical equivalent and refractive astigmatism were -0.4 diopters (D) and 2.2 D, respectively, with no significant shift from preoperative values or values recorded in different follow-up visits. Adjunctive surgeries included phototherapeutic keratectomy, PRK, cataract extraction, and epithelial ingrowth debridement. Complications included residual corneal pathology, mild interface haze, anisometropia, recurrence of pathology, haze after adjunctive PRK, dry eye, epithelial ingrowth, and suspicious ectasia. CONCLUSIONS: Femtosecond laser-assisted sutureless anterior lamellar keratoplasty improves the BSCVA of patients with anterior corneal pathologies with rapid visual rehabilitation and no significant induced astigmatism. Our preliminary results indicate that FALK results remained stable throughout the follow-up period.

MMP-9 and the perioperative management of LASIK surgery.

PURPOSE OF REVIEW: Hyperosmolarity is a central mechanism causing ocular surface inflammation and eye irritation in typical patients suffering from tear dysfunction. Tear composition in dry eyes, or dysfunctional tear syndrome, may destabilize the tear film and cause ocular surface epithelial disease. Increased activity of matrix metalloproteinases (MMPs), especially MMP-9, plays a critical role in wound healing and inflammation and is primarily responsible for the pathologic alterations to the ocular surface that leads to a dysfunctional tear state. RECENT FINDINGS: Altered corneal epithelial barrier function is the cause for ocular irritation and visual morbidity in dry eye disease. The increased MMP-9 activity in dry eyes may contribute to deranged corneal epithelial barrier function, increased corneal epithelial desquamation, and corneal surface irregularity. SUMMARY: Dry eye is one of the most common complications of photorefractive keratectomy and laser in-situ keratomileusis (LASIK). LASIK has both a neurotrophic effect on the cornea and leads to a physical change in corneal shape that results in a change in tear dynamics, leading to ocular surface desiccation. The reduction in tear function after LASIK may induce an increase in osmolarity and consequently raise the concentration of proinflammatory cytokines and MMP-9 in the tear film, which results in dry eyes and insufficient attachment between the corneal flap and the corneal bed. Appropriate diagnosis and management of dysfunctional tear syndrome may lead to less postoperative LASIK complications.

Conjunctivitis: systematic approach to diagnosis and therapy.

Conjunctivitis is a common problem in primary health care. Inflammation of the conjunctiva may result from infection or noninfectious causes. Microbial conjunctivitis may be caused by bacteria, viruses, or parasites. Although usually a benign, self-limited disease in healthy individuals, serious complications (eg, keratitis) may be sight-threatening. Accurate diagnosis and specific treatment of conjunctivitis remain challenging. History taking and physical examination are occasionally insufficient for correct diagnosis, thus laboratory testing may play a vital role in identification of specific pathogen(s). However, diagnostic testing has several limitations, including time-consuming methods, increased cost, and requirement for expertise in performance and interpretation. Treatment with empirical topical antibiotics for suspected infectious conjunctivitis is controversial. Although antibiotic treatment can diminish risk of adverse events and shorten the course of disease, drug resistance, toxicity, and expense are important considerations in management of acute infectious conjunctivitis.

Ocular damage secondary to intense pulse light therapy to the face.

PURPOSE: To promote awareness and prevention of ocular damage that can occur during Intense Pulsed Light (IPL) treatments of the periocular areas. METHODS: A retrospective chart review was conducted of 2 cases involving ocular damage following IPL procedures that were treated at Bascom Palmer Eye Institute for ocular complications. Routine data were collected during ophthalmic examinations. RESULTS: Case 1: A 36-year-old female presented with eye pain, marked pupillary constriction, and anterior uveitis an hour after receiving IPL treatment to the face. Within 1 month, the damage had progressed to posterior synechiae and iris transillumination defects. She continues to have pain and severe photophobia due to permanent iris atrophy and transillumination that have persisted for years. Case 2: A 27-year-old female presented with severe eye pain, vision disturbances, pupillary defects, and anterior uveitis 3 days after IPL of an eyelid freckle. At 2 months follow up, the iris and pupillary defects remain permanent. The patient continues to suffer from photophobia and pain. CONCLUSIONS: The pigmented iris absorbs light in the same wavelength range of IPL, thus remaining vulnerable to IPL exposure, especially when applied to the periocular area. The fact that IPL is not a laser may give people a false sense of security regarding damage to the eye. The cases presented give evidence that periorbital IPL treatment may permanently affect pigmented intraocular structures. It is imperative for treating physicians to be aware of these hazards and to use appropriate eye protection to prevent ocular damage.

Topical Ocular Povidone-Iodine as an Adjunctive Preventative Practice in the Era of COVID-19.

ABSTRACT: Ophthalmologists and patients have an inherent increased risk for transmission of SARS-CoV-2. The human ocular surface expresses receptors and enzymes facilitating transmission of SARS-CoV-2. Personal protective equipment alone provides incomplete protection. Adjunctive topical ocular, nasal, and oral antisepsis with povidone iodine bolsters personal protective equipment in prevention of provider-patient transmission of SARS-CoV-2 in ophthalmology.

Intraoperative use of three-dimensional spectral-domain optical coherence tomography.

BACKGROUND AND OBJECTIVE: To develop a prototype three-dimensional anterior segment spectral-domain optical coherence tomography (SD-OCT) device and demonstrate the feasibility of its use in the operating room. PATIENTS AND METHODS: Single-institution interventional case series including six consecutive patients undergoing Descemet's stripping automated endothelial keratoplasty (DSAEK). The prototype anterior segment SD-OCT was used intraoperatively to search for the presence of interface fluid between the host cornea and the DSAEK graft. RESULTS: Anterior segment SD-OCT was successfully used intraoperatively during DSAEK. After the initial placement of the graft, no fluid was clinically apparent; however, interface fluid was identified by anterior segment SD-OCT in two of the six cases. After additional aspiration, all patients were fluid-free on follow-up anterior segment SD-OCT scanning. CONCLUSION: Intraoperative anterior segment SD-OCT was used successfully to find interface fluid that was clinically undetectable under the microscope. As such, all patients were able to leave the operating room with a fully attached graft.

Experimental model for analyzing cutting resistance by various knives for cataract surgery.

BACKGROUND: The trend in current cataract surgery towards clear corneal incision and sutureless procedures makes us realize the importance of wound construction. For optimal surgical outcomes, we need good surgical instruments. In this study, we employed a resistance recording system to analyze the characteristics of seven commercially available disposable cataract knives and to find clues for the future development of 'good' cataract knives. METHODS: The cutting resistance was recorded during perpendicular penetrations of porcine scleral tissues by cataract knives. This data was processed and analysed mathematically with MATLAB software (The MathWorks, Inc, Natick, MA, USA) to see the resistance wave shapes and their derivatives to show the products' differing characteristics. RESULTS: The wave shapes demonstrated product-dependent characteristics. The average maximum penetration resistance varied from 86.4 to 233 mN. The first order time derivatives also showed distinctive wave shapes. CONCLUSION: We used an experimental model to analyze one aspect of a knife's character. This model can help give clues for future developments, although this is the initial step.

COVID-19 and ophthalmology: an underappreciated occupational hazard.

The proximity required of a thorough biomicroscopic slit-lamp examination may put ophthalmologists at increased risk for respiratory-borne infection with SARS-CoV-2. Conjunctivitis has been described in a few patients with COVID-19 and other coronavirus syndromes. Although SARS-CoV-2 has been detected in the conjunctival secretions or tears of patients with COVID-19 and conjunctivitis, transmission of infection through respiratory droplets to ophthalmologists without eye protection or masks may be the bigger concern.

Multi-tiered screening and diagnosis strategy for COVID-19: a model for sustainable testing capacity in response to pandemic.

Coronavirus disease 2019 (COVID-19), caused by novel enveloped single stranded RNA coronavirus (SARS-CoV-2), is responsible for an ongoing global pandemic. While other countries deployed widespread testing as an early mitigation strategy, the U.S. experienced delays in development and deployment of organism identification assays. As such, there is uncertainty surrounding disease burden and community spread, severely hampering containment efforts. COVID-19 illuminates the need for a tiered diagnostic approach to rapidly identify clinically significant infections and reduce disease spread. Without the ability to efficiently screen patients, hospitals are overwhelmed, potentially delaying treatment for other emergencies. A multi-tiered, diagnostic strategy incorporating a rapid host immune response assay as a screening test, molecular confirmatory testing and rapid IgM/IgG testing to assess benefit from quarantine/further testing and provide information on population exposure/herd immunity would efficiently evaluate potential COVID-19 patients. Triaging patients within minutes with a fingerstick rather than hours/days after an invasive swab is critical to pandemic response as reliance on the existing strategy is limited by assay accuracy, time to results, and testing capacity. Early screening and triage is achievable from the outset of a pandemic with point-of-care host immune response testing which will improve response time to clinical and public health actions.Key messagesDelayed testing deployment has led to uncertainty surrounding overall disease burden and community spread, severely hampering public health containment and healthcare system preparation efforts.A multi-tiered testing strategy incorporating rapid, host immune point-of-care tests can be used now and for future pandemic planning by effectively identifying patients at risk of disease thereby facilitating quarantine earlier in the progression of the outbreak during the weeks and months it can take for pathogen specific confirmatory tests to be developed, validated and manufactured in sufficient quantities.The ability to triage patients at the point of care and support the guidance of medical and therapeutic decisions, for viral isolation or confirmatory testing or for appropriate treatment of COVID-19 and/or bacterial infections, is a critical component to our national pandemic response and there is an urgent need to implement the proposed strategy to combat the current outbreak.

Histopathologic examination of failed grafts in descemet's stripping with automated endothelial keratoplasty.

PURPOSE: To study the histopathologic features of 19 corneal posterior lamellar grafts in eyes for which Descemet's stripping with automated endothelial keratoplasty (DSAEK) has failed. DESIGN: Retrospective case series with clinicopathologic correlation. PARTICIPANTS: Nineteen cases of DSAEK failures undergoing repeat DSAEK or penetrating keratoplasty. METHODS: The histopathologic results of posterior lamellar grafts (also termed DSAEK grafts), recipient corneas, or both from 19 cases of failed DSAEK were examined. MAIN OUTCOME MEASURES: Abnormalities in the DSAEK graft and in the interface between the recipient cornea and the DSAEK graft were assessed. RESULTS: Histopathologic features in 19 failed DSAEK grafts revealed attenuation of endothelial cells (16 cases) and presence in the graft-host interface of fibrocellular tissue (11 cases), retained Descemet's membrane (5 cases), epithelial ingrowth (4 cases), or a combination thereof. Four DSAEK grafts had full-thickness corneal layers at 1 edge. CONCLUSIONS: Presence of interface material, such as fibrocellular tissue, retained Descemet's membrane, and epithelial ingrowth, are potential causes of dislocation. Endothelial attenuation was the most common finding in failed grafts. Decentered DSAEK grafts with full-thickness corneal layers at 1 edge are a potential cause for epithelial ingrowth.

Complications of LASIK flaps made by the IntraLase 15- and 30-kHz femtosecond lasers.

PURPOSE: To describe complications associated with femtosecond laser-assisted flap creation in LASIK surgery. The management and visual outcomes of femtosecond laser complications related to flap creation in LASIK patients are also described. METHODS: All eyes that underwent LASIK with the IntraLase femtosecond laser from September 2003 to June 2006 at a university-based refractive center were included in this retrospective, noncomparative, interventional case series and IntraLase-related LASIK complications are described. All flaps were made with the 15- and 30-kHz IntraLase femtosecond laser. RESULTS: Included in the study were 4772 eyes, of which 44 (0.92%) eyes had direct or indirect complications due to flap creation. Thirty-two eyes had indirect complications (diffuse lamellar keratitis [DLK] and transient light sensitivity)--20 (0.42%) eyes developed DLK (stage 1 to 2) and 12 (0.25%) eyes had transient light sensitivity syndrome. Twelve (0.25%) eyes had direct femtosecond laser flap-related complications--8 (0.17%) eyes had premature breakthrough of gas through the epithelium within the flap margins, 3 (0.06%) eyes had incomplete flaps due to suction loss, and 1 (0.02%) eye had irregular flap due to previous corneal scar. CONCLUSIONS: Less than 1% of eyes had direct or indirect complications due to femtosecond laser flap creation. Laser in situ keratomileusis complications specifically related to the IntraLase femtosecond laser did not cause loss of best spectacle-corrected visual acuity in any eyes.

Second femtosecond laser pass for incomplete laser in situ keratomileusis flaps caused by suction loss.

PURPOSE: To examine the technique of second-pass femtosecond laser to correct an incomplete flap during laser in situ keratomileusis. SETTING: Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida, USA. METHODS: Twenty porcine eyes were assigned to 1 of 4 groups. In the first 2 groups, a flap was created with a femtosecond laser with a centrally black-painted applanator at a 200 microm depth; a second flap was created at a 400 microm depth with the normal applanator. These groups differed by waiting or not waiting for the opaque bubble layer (OBL) to clear. In the third and fourth groups, the eyes were separated into those with and without OBL; however, the same depth was used for the second pass, which was performed after intentional suction loss. After these treatments, the corneas were examined using anterior segment optical coherence tomography (AS-OCT) and the surgical microscope. RESULTS: In the first group (did not wait for OBL to clear), the peripheral shallow cut and the central deep line were observed in the AS-OCT images, with corresponding findings under the surgical microscope. In the second group (waited for OBL to disappear), there were 2 parallel lines on the AS-OCT images; the lines corresponded to dual flaps. In the third and fourth same-depth-cut tests, lines and irregularities were seen on the bed and the back of the flap. CONCLUSION: A second femtosecond laser pass for incomplete flaps, especially when the OBL has cleared, may result in an uneven lamellar cut.

Complications of Descemet's stripping with automated endothelial keratoplasty: survey of 118 eyes at One Institute.

PURPOSE: To compile a survey of complications during and after Descemet's stripping with automated endothelial keratoplasty (DSAEK) in 118 eyes conducted by cornea subspecialists at a single academic center. DESIGN: Retrospective case series. PARTICIPANTS: One hundred eighteen eyes undergoing DSAEK in 99 patients. METHODS: Outcomes of DSAEK performed in 118 eyes by 10 surgeons were reviewed retrospectively. Sixty-four eyes had pseudophakic bullous keratopathy. Forty-one had Fuchs' endothelial dystrophy and cataract. Three had aphakic bullous keratopathy. In 10 eyes, previous DSAEK performed at the same institution failed. Complications of DSAEK were noted from the intraoperative and postoperative periods. Detached DSAEK grafts were repositioned, rebubbled, or both immediately after diagnosis of this complication. MAIN OUTCOME MEASURES: Intraoperative and postoperative complications of DSAEK. RESULTS: Graft detachment was the most common type of complication encountered. In 27 (23%) of 118 eyes, graft detachments were observed. Twenty-five eyes with detached grafts successfully were repositioned or rebubbled after surgery, or both. In 1 eye, a previously detached graft reattached spontaneously. In 1 aphakic eye, the graft detached into the vitreous cavity. In 17 eyes, successful reattachment of the cornea occurred (68%). Twenty-one of the 118 eyes were considered to have failed DSAEK, meaning that persistent edema was present after DSAEK. Seven (6%) demonstrated graft rejection. In 5 eyes (4%), retinal detachment (RD) developed. In 6 (5%), cystoid macular edema developed. In 1 aphakic patient, an air bubble could not be maintained during surgery, and sulfur hexafluoride was injected into the anterior chamber. In 1 eye (1%), epithelial ingrowth developed. One eye (1%) demonstrated blood in the graft interface. In 1 eye (1%), a limited intraoperative suprachoroidal hemorrhage occurred. Two eyes (2%) had pupillary block after surgery that resolved with removal of the air bubble. CONCLUSIONS: Descemet's stripping with automated endothelial keratoplasty has become a popular and effective treatment for corneal endothelial dysfunction, but complications resulting from DSAEK do occur. Graft detachment is the most common complication, but postoperative repositioning or rebubbling, or both, allow for graft reattachment in most cases. Other complications found in this series were graft failure, graft rejection, cystoid macular edema, RD, suprachoroidal hemorrhage, and pupillary block. Retained Descemet's membrane and epithelial ingrowth, are potential causes of dislocation.

Corneal ectasia after excimer laser keratorefractive surgery: histopathology, ultrastructure, and pathophysiology.

PURPOSE: To evaluate the histopathology and ultrastructure of corneas developing ectasia after LASIK or photorefractive keratectomy (PRK). DESIGN: Retrospective case series. PARTICIPANTS: Thirteen specimens from 12 patients undergoing corneal transplantation for progressive ectasia after LASIK (12 specimens) or PRK (1 specimen) were obtained for histopathologic and ultrastructural evaluation. METHODS: All 13 ectatic corneas were submitted in formalin for light microscopy. Nine specimens were bisected, and the second half was placed in 2.5% glutaraldehyde for transmission electron microscopy (TEM). MAIN OUTCOME MEASURES: Corneal histopathology, ultrastructure, and pathophysiology. RESULTS: Light microscopy of the post-LASIK specimens showed corneal epithelial hypoplasia and occasional foci of epithelial hyperplasia, Bowman's layer breaks, a normal stromal thickness of the LASIK flap, a normal thickness of the hypocellular primitive stromal scar, a thinned residual stromal bed (RSB), and larger than normal artifacteous interlamellar clefts in the RSB of the ectatic region. The post-PRK specimen showed similar findings with the addition of a thinned hypercellular fibrotic stromal scar. TEM showed thinning of the collagen lamellae and loss of lamellar number in the RSB of post-LASIK ectasia corneas or throughout the entire corneal stromal bed in the post-PRK ectasia cornea, with the posterior aspect of the corneal stroma being most affected. CONCLUSIONS: Histopathologic and ultrastructural studies suggest that interlamellar and interfibrillar biomechanical slippage occurs when the cornea becomes ectatic after LASIK or PRK in the postoperative stress-bearing regions of the corneal stroma. This 2-phase chronic biomechanical failure process is similar to that seen in keratoconus. Composite sciences classify this chronic biomechanical failure process as interfiber fracture. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Femtosecond laser-assisted sutureless anterior lamellar keratoplasty.

PURPOSE: To report the technique and small case series results of femtosecond laser-assisted sutureless anterior lamellar keratoplasty (FALK) for anterior corneal pathology. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twelve consecutive eyes from 12 patients with anterior corneal scarring. INTERVENTION: Femtosecond laser-assisted sutureless anterior lamellar keratoplasty. MAIN OUTCOME MEASURES: Measured parameters included femtosecond laser settings, technique, uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and complications. RESULTS: Mean follow-up was 12.7 months (range, 6-24). No intraoperative complications were found. Uncorrected visual acuity (VA) improved in 7 eyes (58.3%) compared with preoperative VA. The mean difference between preoperative and postoperative UCVAs was a gain of 2.5 lines (range, unchanged-7 lines). Best-corrected VA was unchanged or improved in all eyes compared with preoperative levels. The mean difference between preoperative and postoperative BCVAs was a gain of 3.8 lines (range, unchanged-8 lines). In 2 eyes, adjuvant surgical procedures were performed (one treated with phototherapeutic keratectomy and the other with photorefractive keratectomy). Six patients (50%) developed dry eye after FALK, which improved during the follow-up period. No graft rejection, infection, or epithelial ingrowth was found in this series of patients. CONCLUSIONS: Femtosecond laser-assisted sutureless anterior lamellar keratoplasty could improve UCVA and BCVA in patients with anterior corneal pathology.