Pressure-Induced Interface Keratitis: A Late Complication Following LASIK

Complications of small incision lenticule extraction

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

Pressure-induced stromal keratopathy after laser in situ keratomileusis: Acute and late-onset presentations

We present a series of 4 cases of pressure-induced stromal keratopathy after laser in situ keratomileusis (LASIK). Four patients (5 eyes) with previous LASIK presented for poor visual acuity and ocular pain because of ocular hypertension. At examination, all cases revealed corneal haze and a space filled with fluid between the surgical flap and the residual stroma. All cases were managed with topical hypotensive treatment and one of them was also treated with a valve drainage device. Topical steroids restriction was indicated in all cases. Intraocular pressure (IOP) was normalized in all cases with subsequent interface fluid resolution and significant improvement of vision in most cases. Early recognition and appropriate treatment for pressure-induced stromal keratopathy is essential to avoid complications associated with prolonged elevated IOP. It is extremely important to measure the IOP in the peripheral cornea because IOP in the central cornea can be incorrectly measured with the characteristic interface fluid developed in this entity.

Delayed onset of pressure-induced interlamellar stromal keratitis in a patient with recurrent uveitis: A case report

INTRODUCTION

Corticosteroid treatment for uveitis can lead to delayed-onset pressure-induced interlamellar stromal keratitis (PISK), even years after laser in situ keratomileusis (LASIK).A 35-year-old man presented to our clinic after experiencing blurred vision in his left eye for 1 month. For the past month, he had been prescribed topical steroid and anti-glaucomatous medication. He had undergone LASIK for both eyes 5 years earlier, and had suffered uveitis attacks in his left eye over the last 2 years.Slit-lamp examination revealed stromal haziness with interface fluid accumulation in the left eye. The left eye showed an intraocular pressure (IOP) of 35 mm Hg and visual acuity of 6/20. Anterior segment ocular coherence tomography (OCT) confirmed the diagnosis of PISK. Steroid treatment was tapered, and latanoprost treatment was started. One month later, the patient's symptoms resolved, with IOP reduced to 10 mm Hg and visual acuity increased to 6/6 in the left eye. Latanoprost treatment was discontinued to avoid potential uveitis reactivation, and the patient's visual field defect progressed and IOP rebounded. Due to evident glaucomatous damage, trabeculectomy was suggested but was refused.

CONCLUSION

Patients with PISK plus uveitis should be treated with a tailored regimen involving corticosteroid and antiglaucomatous medication or surgical intervention based on the individual condition. Early recognition and appropriate treatment may aid in preventing severe visual sequela in such patients.

Pharmacologic Management of Pressure-Induced Stromal Keratopathy after LASIK

PURPOSE

To emphasize the importance of anticipation of pressure-induced stromal keratopathy (PISK) in eyes with a previous history of LASIK.

CASE REPORT

A 40-year-old man developed LASIK-related pressure-induced stromal keratopathy after uneventful phacoemulsification (Phaco) and intraocular lens (IOL) implantation in his left eye. With immediate discontinuation of the steroid drops and initiation of antiglaucoma medication, his visual acuity, interface edema, and haze improved rapidly. One year later, during Phaco with IOL implantation in his other eye, with anticipation of a similar LASIK-related pressure-induced stromal keratopathy, a very brief course of soft steroid therapy was given together with antiglaucoma medication. Intraocular pressure elevation was avoided, and no interface edema or haze was observed.

CONCLUSIONS

This case illustrates that the risk for LASIK-related pressure-induced stromal keratopathy may be reduced with appropriate precautions.

Descemet membrane endothelial keratoplasty and refractive surgery

PURPOSE OF REVIEW

Descemet membrane endothelial keratoplasty (DMEK) has become a first-line treatment in corneal endothelial diseases because of its exceptional clinical outcomes and low complication rates. Because of its improved refractive predictability, DMEK is now also considered for managing cases with endothelial decompensation following previous refractive procedures, or in combination with those. This article reviews the clinical outcomes in these cases and discusses the possibility of refractive interventions following DMEK.

RECENT FINDINGS

DMEK has been successfully performed in eyes after laser in-situ keratomileusis, eyes after anterior chamber intraocular lens (IOL) implantation and aphakic eyes. Often, DMEK is combined with cataract surgery (triple-DMEK). Initial reports on reducing the refractive cylinder by toric IOL implantation are available. Although there are some reports on phacoemulsification and IOL implantation after phakic DMEK, reports on laser refractive procedures following DMEK are lacking.

SUMMARY

In contrast to earlier keratoplasty techniques, DMEK induces on average only mild refractive shifts owing to the 'natural' restoration of the cornea. As such, DMEK may be ideal in managing corneal decompensation in refractive patients. However, further studies are required to assess the safety and efficacy of DMEK after refractive treatment and of refractive procedures following DMEK.

LASIK interface complications: etiology, management, and outcomes

PURPOSE

To describe the etiology, diagnosis, clinical course, and management of LASIK interface complications.

METHODS

Literature review.

RESULTS

Primary interface complications include infectious keratitis, diffuse lamellar keratitis, central toxic keratopathy, pressure-induced stromal keratopathy (PISK), and epithelial ingrowth. Infectious keratitis is most commonly caused by Methicillin-resistant Staphylococcus aureus (early onset) or atypical Mycobacterium (late onset) postoperatively, and immediate treatment includes flap lift and irrigation, cultures, and initiation of broad-spectrum topical antibiotics, with possible flap amputation for recalcitrant cases. Diffuse lamellar keratitis is a white blood cell infiltrate that appears within the first 5 days postoperatively and is acutely responsive to aggressive topical and oral steroid use in the early stages, but may require flap lift and irrigation to prevent flap necrosis if inflammation worsens. In contrast, PISK is caused by acute steroid response and resolves only with cessation of steroid use and intraocular pressure lowering. Without appropriate therapy PISK can result in severe optic nerve damage. Central toxic keratopathy mimics stage 4 diffuse lamellar keratitis, but occurs early in the postoperative period and is noninflammatory. Observation is the only effective treatment, and flap lift is usually not warranted. Epithelial ingrowth is easily distinguishable from other interface complications and may be self-limited or require flap lift to treat irregular astigmatism and prevent flap melt.

CONCLUSIONS

Differentiating between interface entities is critical to rapid appropriate diagnosis, treatment, and ultimate visual outcome. Although initial presentations may overlap significantly, the conditions can be readily distinguished with close follow-up, and most complications can resolve without significant visual sequelae when treated appropriately.

Intraocular gas associated pressure-induced interface keratopathy 8 years after laser in situ keratomileusis

The authors report a clinically distinctive form of elevated intraocular pressure-induced interface keratopathy that occurred after a pars plana vitrectomy with intraocular gas tamponade for a macular hole in the right eye in a 35-year-old woman who had laser in situ keratomileusis in both eyes 8 years previously. The intraocular pressure was increased to 37 mm Hg after surgery. Diffuse lamellar keratitis-like interface infiltration was found with concurrent elevated intraocular pressure. The interface infiltration did not respond to steroids but resolved after the intraocular pressure was controlled. This case suggests that interface keratopathy is associated with increased intraocular pressure. Assessment of intraocular pressure is essential in patients presenting with interface keratopathy, especially in those who have undergone posterior segment operations with gas tamponade.

Interface Fluid Syndrome in Human Eye Bank Corneas after LASIK

PURPOSE

To evaluate the effects of corneal edema on human donor corneas that had previous LASIK using a laboratory model with histologic and ultrastructural correlations.

DESIGN

Experimental study.

PARTICIPANTS

Thirty human eye bank corneas from 15 donors (mean age +/- standard deviation, 49.9+/-8.9 years) who had had previous LASIK surgery (2-8 years before death).

METHODS

The corneas were mounted in an artificial anterior chamber and the corneal endothelium was perfused for up to 5.0 hours with 0.9% saline solution (endothelial cell damage group) or BSS Plus at a pressure of 15 mmHg (control group), or BSS Plus at a pressure of 55 mmHg (high-pressure group). The corneas were evaluated by confocal and specular microscopy before, during, and at the end of the experimental period. Subsequently, the specimens were evaluated by light and electron microscopy.

MAIN OUTCOME MEASURES

Corneal thickness, reflectivity, histology, and ultrastructure.

RESULTS

Endothelial cell damage resulted in an increased (141.5+/-38.8 microm) total corneal thickness relative to controls (52.3+/-33.7 microm), whereas high pressure resulted in a decreased thickness (24.8+/-14.1 microm) relative to controls. This ultimately was due to swelling of the LASIK interface in both groups and swelling of the residual stromal bed (RSB) in the endothelial cell damage group or compression of the RSB and, possibly, the flap in the high-pressure group. A significant increase in corneal reflectivity at the LASIK interface occurred in both groups, primarily due to varying degrees of fluid accumulation and associated hydropic keratocyte degeneration, as well as increased corneal reflectivity in the RSB only in the endothelial cell damage group.

CONCLUSIONS

After LASIK surgery, edematous corneas preferentially hydrate and swell in the paracentral and central interface wound, commonly resulting in a hazy corneal appearance primarily due to keratocyte hydropic degeneration. More severe corneal edema is characterized by the formation of an optically empty space corresponding to an interface fluid pocket. The spectrum of interface fluid syndrome can be described in 3 stages.

Early Transient Visual Acuity Loss After LASIK Due to Steroid-induced Elevation of Intraocular Pressure

PURPOSE

To report the clinical course of early transient reduction of uncorrected visual acuity (UCVA) after LASIK surgery resulting from steroid-induced elevation of intraocular pressure (IOP).

METHODS

Twenty-nine eyes of 15 patients who received topical corticosteroids after uneventful myopic LASIK surgery and had a decrease in UCVA within the first 3 weeks were evaluated retrospectively.

RESULTS

Intraocular pressure increased by 4 to 30 mmHg from preoperative to postoperative days 4 to 20. Twenty-seven of 29 eyes had a decrease in UCVA and/or best spectacle-corrected visual acuity (BSCVA). All eyes, except one, had edema without evidence of inflammation in the interface or the remainder of the cornea. Discontinuation of topical corticosteroids and application of anti-glaucoma medications resulted in a decrease of IOP to normal levels, reduction or disappearance of the edema, and recovery of BSCVA.

CONCLUSIONS

Early onset steroid-induced elevation of IOP after LASIK may cause corneal edema and a sudden decrease in UCVA. Rapid diagnosis and treatment can control IOP and recover the visual loss.

Surgical-glove-related diffuse lamellar keratitis after laser in situ keratomileusis: long-term outcomes

PURPOSE

To study the long-term refractive results in eyes that developed surgical-glove-related diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK).

SETTING

Department of Ophthalmology, Hospital Provincial, Toledo, Spain.

METHODS

This retrospective review analyzed an epidemic of surgical-glove-related DLK over a 5-month period at a single hospital. Twenty-four eyes (24 patients) that developed DLK (DLK group) were compared to 30 eyes (30 consecutive patients) that had surgery during the same time but had an uneventful postoperative course (control group). Follow-up was 12 months in all cases.

RESULTS

Twelve months after LASIK, the mean spherical equivalent was 0.14 diopter (D) +/- 0.36 (SD) in the DLK group and -0.07 +/- 0.33 D in the control group (P=.03). The mean uncorrected visual acuity was 0.91 +/- 0.18 and 0.90 +/- 0.17, respectively (P = .81). The mean best spectacle-corrected visual acuity (BSCVA) was 0.97 +/- 0.08 in the DLK group and 0.99 +/- 0.06 in the control group (P = .42). At 1 year, 91.7% of eyes in the DLK group and 93.3% of eyes in the control group were within +/-0.50 D of the attempted correction (P = .82). The BSCVA was 1.0 or better in 87.5% and 93.3%, respectively (P =.46).

CONCLUSIONS

Early diagnosis and appropriate treatment of glove-related DLK provided visual outcomes that were similar to those in eyes with an uneventful postoperative course. These good results are consistent with those in studies of classic DLK.

Late Onset Diffuse Lamellar Keratitis as a Result of the Toxic Effect of Ecballium Elaterium Herb

PURPOSE

To report a case of late onset diffuse lamellar keratitis (DLK) 11 months after LASIK due to Ecballium elaterium exposure.

METHODS

A 25-year-old man underwent bilateral LASIK. No complications were observed during the early postoperative period.

RESULTS

Eleven months after LASIK surgery, grade II DLK was diagnosed after an Ecballium elaterium herb seed burst and splashed into the patient's left eye. Topical steroid treatment was administered and DLK healed in 2 weeks without complication.

CONCLUSIONS

Although DLK typically develops in the early postoperative period, it could occur months after surgery. Treatment should begin as soon as DLK is diagnosed.

Interface Corneal Edema Secondary to Steroid-induced Elevation of Intraocular Pressure Simulating Diffuse Lamellar Keratitis

PURPOSE

To describe interface corneal edema secondary to steroid-induced elevation of intraocular pressure (IOP) following LASIK.

METHODS

Retrospective observational case series. Diffuse interface edema secondary to steroid-induced elevation of IOP was observed after LASIK simulating diffuse lamellar keratitis (DLK) in 13 eyes. Mean patient age was 31.4 +/- 5.3 years. Patients were divided into two groups according to provisional misdiagnosis: DLK group (group 1) comprised 11 eyes and infection group (group 2) comprised 2 eyes (microbial keratitis). Mean follow-up was 8.1 +/- 0.5 weeks.

RESULTS

In the DLK group, typical diffuse haze was confined to the interface and extended to the visual axis, impairing vision in all eyes. Provisional diagnosis was late-onset DLK and topical steroids were started. Repeat examination showed elevated IOP as measured at the corneal center and periphery using applanation tonometry (mean 19.1 mmHg and 39.5 mmHg, respectively), causing interface edema with evident interface fluid pockets. Steroids were stopped and topical anti-glaucoma therapy was started. The interface edema decreased and at the end of follow-up the corneal transparency was restored and IOP dropped to normal values. The infection group demonstrated a microbial keratitis-like reaction and underwent flap lifting and interface wound debridement and biopsy with administration of fortified antibiotics and steroids. After elevated IOP was detected, steroids and antibiotics were stopped and topical anti-glaucoma therapy was started, resulting in the resolution of the interface edema.

CONCLUSIONS

Interface fluid syndrome secondary to steroid-induced elevation of IOP might develop in steroid responders after LASIK with a misleading clinical picture simulating DLK or infectious keratitis. Management includes stopping topical steroids and starting topical antiglaucoma therapy.

Avoidance, recognition, and management of LASIK complications

PURPOSE

To provide important concepts of the latest developments in laser in situ keratomileusis (LASIK) complication avoidance, recognition, and management.

DESIGN

A perspective.

METHODS

A comprehensive literature search and review of a total of 816 publications that discussed LASIK complications from 1992 to 2005 was conducted.

RESULTS

The risk of visually threatening complications is inherent in any ophthalmologic surgical procedure. Not only does LASIK require the use of several complex medical devices, but there can be significant human variation in response to this surgical intervention. As a result, many potential complications can occur after LASIK. The risk of many complications can be mitigated by appropriate patient selection and preoperative, surgical, and postoperative care. Unforeseen complications will occur, despite meticulous planning, and must be managed. Important current developments in the avoidance, recognition, and management of LASIK complications are reviewed.

CONCLUSIONS

Complications as a result of LASIK can threaten vision and may cause debilitating symptoms in an otherwise healthy eye. Advancing our understanding of the prevention and management of the complications of LASIK is an endeavor that must be continued as long as refractive surgery is performed.

A Standardized Drawing Scheme to Document Corneal Changes Following Refractive Corneal Surgery

PURPOSE

To present a systematic and standardized drawing scheme for unambiguous and reproducible documentation of corneal changes after incisional techniques, coagulative procedures, and lamellar and surface ablation excimer surgery.

METHODS

Standardized symbols in five colors representing specific corneal conditions after incisional surgery (eg, radial keratotomy, astigmatic keratotomy), coagulative procedures (eg, laser thermokeratoplasty, conductive keratoplasty), surface ablation (eg, photorefractive keratectomy, laser subepithelial keratomileusis, epi-LASIK), and LASIK are used to record corneal changes in frontal and sectional views.

RESULTS

Corneal changes following refractive corneal surgery were documented.

CONCLUSIONS

The drawing scheme permits specific features to be followed in the clinic in a clear and unambiguous manner.

Considerations of Glaucoma in Patients Undergoing Corneal Refractive Surgery

Glaucoma patients present a unique set of challenges to physicians performing corneal refractive surgery. Corneal thickness, which is modified during corneal refractive surgery, plays an important role in monitoring glaucoma patients because of its effect on the measured intraocular pressure. Patients undergo a transient but significant rise in intraocular pressure during the laser-assisted in situ keratomileusis (LASIK) procedure with risk of further optic nerve damage or retinal vein occlusion. Glaucoma patients with filtering blebs are also at risk of damage to the bleb by the suction ring. Steroids, typically used after refractive surgery, can increase intraocular pressure in steroid responders, which is more prevalent among glaucoma patients. Flap interface fluid after LASIK, causing an artificially low pressure reading and masking an elevated pressure has been reported. The refractive surgeon's awareness of these potential complications and challenges will better prepare them for proper management of glaucoma patients who request corneal refractive surgery.