Incidence Of Diffuse Lamellar Keratitis Research Articles

Effects of Chilled Saline Irrigation on SMILE Surgery.

To investigate the effect of ultra-early visual correction and prognosis of myopic astigmatism after irrigation with the chilled balanced salt solution (BSS) during small incision lenticule extraction (SMILE) surgery. A prospective case-control study was enrolled from 202 patients (404 eyes) who had SMILE, and randomly divided into an intervention group and a control group (each group was 101 cases [202 eyes]). After lenticule extraction on SMILE, the corneal cap and the corneal incision were flushed with chilled saline in the intervention group, whereas the control group was flushed with room temperature saline. All patients in the two groups were examined for early complications before and 2 hours, 24 hours, and 7 days after surgery and the results were compared, and statistically analyzed, including the recovery degree of naked eye vision, ocular irritation symptoms, opaque bubble layer, diffuse lamellar keratitis (DLK), uncorrected distance visual acuity (UDVA), and corrected distance visual acuity. The ocular irritation symptoms in the intervention group were milder than those in the control group at 2 hours after surgery, and the recovery of visual acuity at 2 and 24 hours after surgery was significantly faster than that in the control group, but there was no statistical difference in UDVA between the two groups at 7 days after surgery (P > .05). The incidence of DLK in the intervention group was lower than that in the control group, and the difference was significant (P = .041). Chilled BSS irrigation can reduce the emergency response of corneal tissue after SMILE, relieve ocular irritation, promote vision recovery, and relatively reduce incidence of early complications. [J Refract Surg. 2023;39(4):282-287.].

Five-Year Incidence, Management, and Visual Outcomes of Diffuse Lamellar Keratitis after Femtosecond-Assisted LASIK

Femtosecond (FS) lasers initially had a higher incidence of diffuse lamellar keratitis (DLK) compared with microkeratome flap creation. It has been theorized that higher-frequency lower-energy (HFLE) FS lasers would reduce the incidence of DLK. Our study sought to evaluate the incidence of newer HFLE FS lasers with pulse frequencies above 60 kHz. It was a retrospective case-control study evaluating the incidence of DLK following flap creation with one of three FS lasers (AMO iFs, WaveLight FS200, Zeiss VisuMax). Uncomplicated LASIK cases were included as the control group (14,348 eyes) and cases of DLK were recorded in the study group (637 eyes). Of the 637 cases of DLK, 76 developed stage II, 25 progressed to stage III, and only three developed stage IV DLK. The overall incidence rate of DLK was 4.3%; it has fallen with the invention of newer HFLE FS lasers and is approaching the DLK incidence rates of DLK with microkeratome.

Keratitis following laser refractive surgery: Clinical spectrum, prevention and management.

Laser refractive surgery (LRS) is one of the most demanding areas of ophthalmic surgery and high level of precision is required to meet outcome expectations of patients. Post-operative recovery is of vital importance. Keratitis occurring after LRS can delay visual recovery. Both surface ablations [Photorefractive keratectomy (PRK)] as well as flap procedures [Laser in-situ keratomileusis (LASIK)/Small incision lenticule extraction] are prone to this complication. Reported incidence of post-LRS infectious keratitis is between 0% and 1.5%. The rate of infections after PRK seems to be higher than that after LASIK. Staphylococci, streptococci, and mycobacteria are the common etiological organisms. About 50–60% of patients present within the first week of surgery. Of the non-infectious keratitis, diffuse lamellar keratitis (DLK) is the most common with reported rates between 0.4% and 4.38%. The incidence of DLK seems to be higher with femtosecond LASIK than with microkeratome LASIK. A lot of stress is laid on prevention of this complication through proper case selection, asepsis, and use of improved protocols. Once keratitis develops, the right approach can help resolve this condition quickly. In cases of suspected microbial keratitis, laboratory identification of the organism is important. Most lesions resolve with medical management alone. Interface irrigation, flap amputation, collagen cross-linking and therapeutic penetrating keratoplasty (TPK) are reserved for severe/non-resolving cases. About 50–75% of all infectious keratitis cases post LRS resolve with a final vision of 20/40 or greater. Improved awareness, early diagnosis, and appropriate intervention can help limit the damage to cornea and preserve vision.

Risk Factors for Sporadic Diffuse Lamellar Keratitis After Microkeratome Laser-Assisted In Situ Keratomileusis: A Retrospective Large Database Analysis.

To determine the factors associated with sporadic diffuse lamellar keratitis (DLK) after microkeratome laser-assisted in situ keratomileusis (LASIK). This large database retrospective study included consecutive cases of LASIK performed between 2007 and 2016 at Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into 2 groups according to whether or not they subsequently developed DLK. A total of 24,026 eyes of 12,013 patients with a mean age of 32.9 ± 10.3 years were included. Post-LASIK DLK developed in 464 eyes (1.9%), and the annual rate decreased from 7.1% (2007) to 1.7% (2016) (P < 0.001). The DLK group had a higher proportion of males (58.5% vs. 52.1%, P = 0.006), greater preoperative central corneal thickness (549.5 ± 32.6 vs. 545.3 ± 30.5 μm, P = 0.005), and a lower proportion of high astigmatism (>3 D) (0.4% vs. 1.6%, P = 0.05). The DLK group had a higher proportion of previous LASIK treatment (2.8% vs. 1.3%, P = 0.006), Moria M2 (rather than the SBK) microkeratome (71.1% vs. 34.0%, P < 0.001), smaller suction ring number (P < 0.001), greater stop size (P < 0.001), and greater flap thickness (119.2 ± 50.4 vs. 110.8 ± 22.2, P = 0.007). In multivariable analysis, a smaller suction ring number [odds ratio (OR) 0.89, P = 0.04], Moria M2 microkeratome (OR 5.26, P < 0.001), larger optical zone (OR = 2.04, P = 0.01), and higher spherical equivalent (OR = 1.08, P = 0.02) were associated with DLK. In the modern LASIK era, the incidence of DLK continues to decrease. Higher preoperative ametropia, smaller suction ring number, an older type of microkeratome, and larger optical zones are associated with higher DLK rates after LASIK.

The effect of humidity and temperature on visual outcomes after myopic corneal laser refractive surgery

ObjectiveTo determine whether procedure room environmental conditions are associated with outcomes after myopic laser in situ keratomileusis (LASIK) or laser-assisted keratomileusis (LASEK).DesignRetrospective chart review.ParticipantsEight hundred sixty-three eyes of 458 consecutive patients at a university-based academic practice.MethodsWe reviewed the medical records of consecutive patients who underwent LASIK or LASEK over a 3-year period. Linear mixed regression models were used to investigate the association of laser room temperature and humidity with the outcomes of visual acuity and postoperative manifest spherical equivalent refraction. Repeated measures logistic regression models were used for the outcomes of diffuse lamellar keratitis (DLK) and need for enhancement surgery.ResultsSubjects were on an average 38.6 years old at the time of surgery (standard deviation [SD] =10.3) and the average spherical equivalent refraction of eyes was 3.8 diopters (SD =2.03). Regression models did not reveal a significant association between temperature and uncorrected distance visual acuity (UDVA) or corrected distance visual acuity (CDVA), or between humidity and UDVA (P>0.05 for all). However, increased humidity was associated with a small but statistically significant improvement in CDVA after LASIK at 1 day, 1 month, 3 months, and 1 year postoperatively (P<0.05 for all). There was no significant association between temperature and humidity and the need for enhancement, the incidence of DLK, or postoperative manifest refraction.ConclusionWhile increased laser room humidity was consistently associated with small improvements in CDVA after myopic LASIK over time, variations in room temperature and humidity were not associated with UDVA, the need for enhancement, the incidence of DLK, or refraction after myopic LASIK or LASEK.

Diffuse lamellar keratitis after small-incision lenticule extraction

To determine the incidence and clinical features of diffuse lamellar keratitis (DLK) after small-incision lenticule extraction (SMILE). Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China. Retrospective case control study. Small-incision lenticule extraction for myopia was performed from September 1, 2011, to October 31, 2013. Preoperative clinical characteristics; treatment parameters; and intraoperative and postoperative complications, including the incidence, severity, clinical outcome, and resolution of DLK, were recorded. The independent t test, chi-square test, univariate repeated measures, and multivariate linear regression analysis were used to make statistical comparisons between eyes that developed DLK and those that did not. The study enrolled 1112 eyes (590 patients). Eighteen eyes (1.6%) (11 patients) developed DLK. These patients presented 1 to 3 days postoperatively with mild to moderate inflammation. Thirteen eyes (72.2%) had stage 1 DLK, 4 (22.2%) had stage 2, and 1 (5.6%) had stage 3. After intensive treatment with topical corticosteroids, the stage 1 and stage 2 cases resolved within 3 weeks and the stage 3 case resolved in 1 month. The postoperative corrected distance visual acuity was the same or better than preoperatively in all eyes. There was a statistically significant increase in the incidence of DLK with thinner lenticules (P = .02) and larger diameter lenticules (P = .01), although multifactorial analysis showed lenticule thickness to be the only factor (P = .03). Diffuse lamellar keratitis is a potential complication after small-incision lenticule extraction, although it had a low incidence. The risk factors for DLK must be further elucidated. No author has a financial or proprietary interest in any material or method mentioned.

Comparison of DLK incidence after laser in situ keratomileusis associated with two femtosecond lasers: Femto LDV and IntraLase FS60

PurposeTo compare the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with flap creation using the Femto LDV and IntraLase™ FS60 femtosecond lasers.0MethodsA total of 818 consecutive myopic eyes had LASIK performed using either Femto LDV or IntraLase FS60 for flap creation. The same excimer laser, the Allegretto Wave® Eye-Q Laser, was used for correcting refractive errors for all patients. In the preoperative examination, uncorrected distance visual acuity, corrected distance visual acuity, and manifest refraction spherical equivalent were measured. At the postop examination, the same examinations were performed along with a slit-lamp biomicroscopic examination, and patients with DLK were classified into stages. For the statistical analysis of the DLK occurrence rate and the visual and refractive outcomes, the Mann-Whitney’s U-test was used.ResultsIn the Femto LDV group with 514 eyes, 42 (8.17%) had DLK. In the IntraLase FS60 group with 304 eyes, 114 (37.5%) had DLK. There was a statistically significant difference in the DLK incidence rate between these groups (P < 0.0001). Both groups had excellent visual and refractive outcomes. Although low levels of DLK were observed for both groups, they did not affect visual acuity.ConclusionWhile there were significantly fewer incidences of low level DLK when using Femto LDV, neither femtosecond laser induced high levels of DLK, and any postoperative DLK cleared up within 1 week. Therefore, both lasers provide excellent results, with no clinical differences, and both excel at flap creation for LASIK.

Diffuse lamellar keratitis after laser in situ keratomileusis with femtosecond laser flap creation

To identify possible associations with the development of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with femtosecond laser flap creation. University-based academic practice, Ann Arbor, Michigan, USA. Case-control study. Myopic LASIK was performed between October 2006 and December 2010 using an Intralase 60 kHz femtosecond laser for flap creation. Preoperative clinical characteristics, treatment parameters, and intraoperative and postoperative complications were recorded. Statistical comparisons were made using t, chi-square, and Fisher exact tests and repeated-measures logistic regression to adjust for inter-eye dependency. The study enrolled 801 eyes (419 patients). Ninety-nine eyes (12.4%) of 70 patients developed DLK; most cases comprised mild flap interface inflammation and were treated with a routine postoperative antiinflammatory regimen. Twenty-two eyes (2.7%) required more than 1 week of antiinflammatory treatment. There was a statistically significant increase in the incidence of DLK with larger flap diameter (P=.0171), higher side-cut energy (P=.0037), and higher raster energy (P=.0033). Patients with DLK were less likely to achieve corrected distance visual acuity of 20/20 or better 1 day postoperatively (P=.0453). The difference in acuity was no longer present at 1 week. There were no significant associations between the incidence of DLK and preoperative refractive error, flap thickness, ablation depth, or other treatment parameters. Diffuse lamellar keratitis after LASIK with femtosecond laser flap creation tended to be mild with little effect on visual acuity. Higher energy level for flap creation and larger flap diameter were associated with an increased risk for DLK.

Femtosecond Sub-Bowman Keratomileusis: A Prospective, Long-term, Intereye Comparison of Safety and Outcomes of 90- Versus 100-μm Flaps

To analyze the long-term safety profile, visual and refractive results, and incidence of complications between sub-Bowman keratomileusis with 90- and 100-μm flaps. Prospective, randomized, comparative clinical study. A total of 385 candidates (770 eyes) underwent bilateral, single-sitting, sub-Bowman keratomileusis, with flap creation (90 or 100 μm) on IntraLase 60-kHz (Abott Medical Optics) and ablation on Technolas 217z100 (Technolas PV) . Right and left eyes were randomized to undergo 90- or 100-μm flap procedures. Preoperative and postoperative assessment included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and topographic analysis. All cases were followed up until 12 months after surgery. After excluding cases lost to follow-up, a final analysis of 368 patients was carried out (368 eyes in each of the 2 groups). The main outcome measures were BSCVA, UCVA, complication rates, and residual spherical equivalent refractive error. The mean preoperative values were: spherical equivalent, -6.08 ± 2.7 diopters (D; 90-μm group) and -5.99 ± 2.8 D (100-μm group; P = .7); and logarithm of the minimal angle of resolution BSCVA, 0.01 ± 0.03 (90-μm group) and 0.01 ± 0.04 (100-μm group: P = .8). Postoperative 12-month values were: spherical equivalent, -0.02 ± 0.4 D (90-μm group) and -0.01 ± 0.4 D (100-μm group; P = .8); logarithm of the minimal angle of resolution BSCVA, -0.05 ± 0.07 (90-μm group) and -0.04 ± 0.07 (100-μm group; P = .8); and logarithm of the minimal angle of resolution UCVA, 0.012 ± 0.01 (90-μm group) and 0.017 ± 0.02 (100-μm group; P = .2). No loss of BSCVA was seen in any case. The efficacy indices were 1.039 ± 0.21 (90-μm group) and 1.014 ± 0.24 (100-μm group; P = .2); safety indices were 1.163 ± 0.21 (90-μm group) and 1.158 ± 0.22 (100-μm group; P = .6); and vision difference indices were 0.09 ± 0.14 (90-μm group) and 0.10 ± 0.15 (100-μm group; P = .1). Both groups had a low but comparable incidence of diffuse lamellar keratitis and microstriae. However, the incidence of microstriae (although visually asymptomatic) was significantly higher in ablation with spherical equivalent of -9 D or more compared with lesser ablations (6.7% vs 0.8%; P < .001). The 1-year follow-up of femtosecond sub-Bowman keratomileusis with 90- and 100-μm flaps suggests that both the flap options have comparable outcomes.

Incidence of diffuse lamellar keratitis after LASIK with 15KHz, 30KHz, and 60KHz femtosecond laser flap creation

Incidence of diffuse lamellar keratitis after LASIK with 15KHz, 30KHz, and 60KHz femtosecond laser flap creation

Incidence of diffuse lamellar keratitis after LASIK with 15 KHz, 30 KHz, and 60 KHz femtosecond laser flap creation

To compare the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with flap creation using the 15 kHz (FS15), 30 kHz (FS30), or 60 kHz (FS60) femtosecond laser. University-based academic practice, Ann Arbor, Michigan, USA. Retrospective comparative case series. Consecutive myopic LASIK cases performed between January 1, 2005, and June 1, 2007, using the IntraLase FS15, FS30, or FS60 femtosecond laser for flap creation were reviewed. Preoperative clinical characteristics, treatment parameters, and intraoperative and postoperative complications were recorded. Statistical comparisons were made using repeated measures analysis, analysis of variance, chi-square, and Fisher exact tests. Five hundred twenty eyes of 274 patients were included in the study. One hundred seventy-six eyes (93 patients) were treated with the FS15 laser, 180 eyes (93 patients) with the FS30 laser, and 164 eyes (89 patients) with the FS60 laser. Seventeen eyes (10%) in the FS15 laser group, 24 eyes (13%) in the FS30 laser group, and 23 eyes (14%) in the FS60 laser group developed DLK. There was no statistically significant difference in the incidence of DLK between the 3 groups (P = .68). There was no significant difference in the incidence of DLK between the FS15, FS30, and FS60 groups.

Outbreak of diffuse lamellar keratitis caused by marking-pen toxicity

To examine the evidence that a series of cases of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) was caused by a type of marker pen. Eye Institute, Auckland, New Zealand. During a 10-week period, 522 consecutive LASIK procedures were performed using a 60 Hz IntraLase femtosecond laser (IntraLase Corp.) to create the LASIK flap and a 217Z 100 Hz excimer laser (Bausch & Lomb) to perform the refractive ablation. As standard practice, a marking pen was used to enable accurate flap realignment. Three weeks after a sudden increase in the incidence of DLK was identified, one of the 5 surgeons performed 5 consecutive bilateral cases using the marking pen in the right eyes but not in the left eyes. Of the 522 LASIK cases (119 without marking pen, 403 with marking pen), DLK developed in 49 (9.4%). No eye treated without the marking pen developed DLK; of those in which the marking pen was used, 49 (12.2%) developed DLK (P<0.0001, Fischer exact test; odds ratio, 27). In the 5 consecutive bilateral cases in which the marking pen was used in the right eye but not the left eye, 4 right eyes and no left eye developed DLK (P=0.03). Forty-five of the 49 eyes with DLK quickly recovered. The other 4 developed central toxic keratopathy. There is strong statistical evidence that the marking pen was a factor in the occurrence of DLK.

Incidence of diffuse lamellar keratitis after laser in situ keratomileusis associated with the IntraLase 15 kHz femtosecond laser and Moria M2 microkeratome

To analyze the incidence of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) performed with an IntraLase 15 kHz femtosecond laser (IntraLase, Corp.) or a Moria M2 mechanical microkeratome (Moria SA). Vissum Madrid, Madrid, Spain. This retrospective study compared the incidence of DLK in consecutive LASIK procedures performed with the IntraLase 15 kHz femtosecond laser (study group) or the Moria M2 microkeratome (control group). Two surgeons performed both types of surgeries (femtosecond laser and microkeratome) using the same excimer laser (Technolas 217, Bausch & Lomb). During the first week postoperatively, topical dexamethasone drops were applied 8 times daily in the femtosecond group and 4 times daily in the mechanical microkeratome group. A total of 2000 consecutive eyes were analyzed (1000 eyes in each group). Diffuse lamellar keratitis stage 2 developed in 1 patient in each group; DLK stage 3 developed in 4 patients in the study group and in no patient in the control group (P = .03). Despite more intense postoperative steroid treatment, DLK seemed to occur more frequently after LASIK performed with the IntraLase 15 kHz femtosecond laser than after LASIK performed with the Moria M2 microkeratome.

Confocal Microscopy Comparison of IntraLase Femtosecond Laser and Moria M2 Microkeratome in LASIK

To analyze the quality of LASIK flaps created using a femtosecond laser or a mechanical microkeratome. A prospective study of consecutive bilateral LASIK flaps (100 patients) created with a 15 kHz femtosecond laser (IntraLase) or with a mechanical microkeratome (Moria M2) was performed. Outcome measures included visual and refractive outcomes, flap dimensions, and intraoperative complications. The first consecutive ten patients (20 eyes) were examined using confocal microscopy 1 and 3 months following surgery. No significant differences were noted in the visual outcomes between groups (t test, P > .05 for all comparisons). Analysis of superficial measurements revealed more round flaps and greater predictability in surface dimensions for the femtosecond laser group (t test, P = .016). Mean deviation of flap thickness from target was the same for both instruments, 10 microm, with greater variability for the mechanical microkeratome. The incidence of diffuse lamellar keratitis was significantly greater in the femtosecond laser group (17%) than in the mechanical group (0%) (chi-square test, P < .001). Confocal microscopy revealed a higher wound healing opacity index in the femtosecond laser group. Although the clinical results are similar, the femtosecond laser produces LASIK flaps with more accurate dimensions compared to the mechanical microkeratome.

Surgical Glove-Associated Diffuse Lamellar Keratitis

To demonstrate a potential cause of a prolonged epidemic of diffuse lamellar keratitis (DLK). This retrospective review analyzed an epidemic of diffuse lamellar keratitis over a 3-year period in a single surgery center. Altering the brand of surgical gloves used during surgery was associated with an elimination of the DLK epidemic. Optical microscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared (FTIR) spectroscopy were performed on both brands of surgical gloves to allow for comparisons and determine possible surface contaminants responsible for the DLK outbreaks. The incidence of DLK during the epidemic ranged from 2% to 38% on a quarterly basis for the 3-year period. A change in the brand of surgical gloves resulted in a cessation of DLK. Surface analysis of both brands of gloves revealed extensive silicone oil contamination on the internal and external surfaces of the DLK-associated gloves and insignificant amounts of silicone oil on the external surface of the DLK-free gloves. Silicone oil contamination of surgical gloves appears to be associated with epidemic DLK.

The epidemiology of diffuse lamellar keratitis.

To report the incidence and outcomes of diffuse lamellar keratitis (DLK) after LASIK and to analyze potential causative factors. Retrospective review of 15,119 cases (11,232 primary procedures and 3887 enhancements) from 7168 patients undergoing LASIK from May 1995 through October 2002, comparing preoperative data and postoperative outcomes for each case developing DLK to patients in the study population and a control series of eyes that did not develop DLK. We identified 61 eyes (0.40%) that developed DLK after LASIK. Three study groups were identified based on sterilization protocols used: (1) steam autoclave without reservoir (8348 cases), (2) cassette autoclave with reservoir (6771 cases), (3) steam autoclave without reservoir and new instrument cleaner (1758 cases). Significantly more eyes developed DLK with Protocol 2 (47 cases, 0.94%) than with Protocol 1 (11 cases; 0.1%; P < 0.0001) or Protocol 3 (3 cases, 0.2%; P < 0.0005). There was no significant difference in the incidence of DLK in Protocol 1 versus Protocol 3. DLK was significantly more common after primary procedures than with enhancement procedures only under Protocol 2. No individual developed DLK after more than 1 procedure. Treatment protocols included frequent topical steroids only (24 cases, 39.3%), frequent topical steroids and oral steroids (19 cases, 31.2%), or topical and oral steroids combined with lifting and irrigating beneath the flap (18 cases, 29.5%). Final refractions and visual acuities were not significantly different in eyes that developed DLK and those that did not. DLK is a nonspecific inflammatory response to multiple stimuli that cannot be attributed solely to individual variation in the inflammatory response, the microkeratome, or material deposited by the microkeratome. Sterilizers with reservoirs may cause some cases of DLK. With appropriate diagnosis and treatment, DLK should resolve without sequelae, yielding visual outcomes comparable to cases with uneventful postoperative courses.

The Efficacy of Hourly Prophylactic Steroids in Diffuse Lamellar Keratitis Epidemic

Purpose: To investigate the inciting agent, clinical features, and the efficacy of hourly steroids in the prophylaxis in a diffuse lamellar keratitis (DLK) epidemic. Methods: One hundred and five eyes of 58 patients that had DLK after LASIK were included in the study. To identify the cause of the epidemic, some interventions were made: irrigation solution was changed from BSS to Ringer lactate (week 5), wiping of the interface with a sponge was discontinued (week 6), the air conditioner in the LASIK room was checked (week 6), the routine postoperative topical regimen was changed from fluoromethalone and fluoroquinolones 4 times a day to hourly prednisolone acetate or dexamethasone sodium and fluoroquinolones (week 7), and the trademark of the drape used was changed (week 12). Results: There was no statistical difference in any of the attack rates associated with variables including BSS versus Ringer lactate (9.9 vs. 14%, p = 0.4), and air conditioner check with wiping versus not wiping the interface with the microsurgical sponge (14.0 vs. 18.2%, p = 0.6). There was a significant decrease in the attack rate from 18.2 to 5.3% with use of the hourly prophylactic topical steroids (p = 0.012). After introduction of a new trademark of the drape, the incidence of DLK was further reduced from 5.3 to 0.7% (p = 0.016). Conclusion: The cause in a particular DLK epidemic should be identified and eliminated adopting a scientific approach. Hourly steroid use for prophylaxis is recommended until the etiologic agent responsible has been identified.

Diffuse lamellar keratitis after laser in situ keratomileusis with the Moria LSK-One and Carriazo-Barraquer microkeratomes

Purpose To assess risk factors for and incidence of diffuse lamellar keratitis (DLK) and to investigate whether microkeratome design is associated with the incidence of DLK. Setting The Laser Eye Consultants of Boston, Boston and Waltham, Massachusetts, USA. Methods In a retrospective nonrandomized comparative study, 1122 consecutive primary laser in situ keratomileusis (LASIK) treatments (584 patients) were analyzed to determine the incidence of DLK using 2 different microkeratome designs (Moria LSK-One [LSK] and Moria Carriazo-Barraquer [C-B]). The incidence of DLK was as determined by clinical signs. Results The overall incidence of DLK was 2.23%. The incidence in the LSK and C-B groups was 1.09% and 4.38%, respectively, with a statistically significant difference in incidence between the 2 groups ( P<.01). Epithelial irregularities increased the risk for DLK. There was no significant statistical difference in sex, age, operating room location, type of laser, or time of day the surgery was performed between the 2 groups or between eyes that had DLK and eyes without DLK. The incidence of DLK using the C-B microkeratome fell significantly after May 2000, when new cleaning methods for this device were introduced. Conclusions Different microkeratomes and how they are maintained may influence the incidence of DLK. Diffuse lamellar keratitis is more common after LASIK in a setting of epithelial irregularities, whether or not an actual epithelial defect is created.

Atopy: a patient-specific risk factor for diffuse lamellar keratitis

Objective To identify whether atopy is a patient-specific risk factor for the development of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK). Design Retrospective survey study. Participants Three hundred sixty consecutive patients who underwent same-day bilateral myopic astigmatic primary LASIK procedures during March 1, 2000, through July 31, 2000. Methods We collected data for 360 consecutive patients undergoing LASIK during a 4-month period. On preoperative medical history questionnaires, patients self-identified whether they were atopic. All patients also indicated whether they were taking antiallergy medications or were untreated for allergy. Main outcome measures The incidence of DLK after LASIK surgery. Results The risk of DLK in untreated atopic patients was much greater than the risk of DLK among nonatopics (odds ratio, 5.85; 95% confidence interval, 2.89–11.85; P = 0.001). However, the risk of DLK among atopic patients taking an oral systemic nonsedating histamine receptor 1 antagonist and among nonatopic patients did not differ significantly (odds ratio, 0.54; 95% confidence interval, 0.12–2.46; P = 0.43). Conclusions Atopy is a patient-specific risk factor for the development of DLK after primary bilateral LASIK for either myopia or myopic astigmatism. Atopic individuals benefit from preoperative treatment to minimize the incidence of DLK and the potential for visual loss.

Epithelial ingrowth after laser in situ keratomileusis: clinical features and possible mechanisms

PURPOSE: To analyze the incidence, clinical course, and possible mechanisms of epithelial ingrowth after laser in situ keratomileusis (LASIK). DESIGN: Interventional case series. METHODS: Retrospective evaluation of 4,867 eyes of 2,502 patients who had LASIK. The type of microkeratome (LSK-One or MK-2000), corneal flap thickness, and clinical course were analyzed. We also compared the cutting characteristics of both microkeratomes in pig cadaver eyes by scanning electron microscopy. RESULTS: The frequency of epithelial ingrowth was significantly greater in the MK-2000 (34 of 1,680 eyes; 2.0%) than the LSK-One group (30 of 3,187 eyes; 0.94%; P = .001). In 24 eyes (37.5%), blood, cell infiltration, ointment under the corneal flaps, or epithelial defect were detected at the area of epithelial ingrowth postoperatively. The incidence of epithelial ingrowth was correlated with the incidence of epithelial defect during surgery ( P < .001) and with incidence of diffuse lamellar keratitis after surgery ( P = .003). Flap thickness was thinner in eyes with epithelial ingrowth (126.0 ± 29.1 μm) compared with flap thickness in eyes without epithelial ingrowth (133.8 ± 27.3 μm; P < .001). Scanning electron microscopy showed clear differences in the appearance of flap edges created by the two types of microkeratomes. Epithelial ingrowth disappeared or remained unchanged in 54 eyes (90%) and progressed in six cases (10%). CONCLUSIONS: Poor adhesion caused by excessive hydration due to epithelial defect as well as by foreign bodies between the flap stromal bed and thickness and morphologic characters of the corneal flap, depending on the type of microkeratomes, are related factors for development of epithelial ingrowth.