Airbag deployment-related eye injuries.

OBJECTIVE: We studied the correlation between airbag deployment and eye injuries using 2 different data sets. METHODS: The registry of the Finnish Road Accident (FRA) Investigation Teams was analyzed to study severe head- and eyewear-related injuries. All fatal passenger car or van accidents that occurred during the years 2009-2012 (4 years) were included (n = 734). Cases in which the driver's front airbag was deployed were subjected to analysis (n = 409). To determine the proportion of minor, potentially airbag-related eye injuries, the results were compared to the data for all new eye injury patients (n = 1,151) recorded at the Emergency Clinic of the Helsinki University Eye Hospital (HUEH) during one year, from May 1, 2011, to April 30, 2012. RESULTS: In the FRA data set, the unbelted drivers showed a significantly higher risk of death (odds ratio [OR] = 5.89, 95% confidence interval [CI], 3.33-10.9, P = 2.6E-12) or of sustaining head injuries (OR = 2.50, 95% CI, 1.59-3.97, P = 3.8E-5). Only 4 of the 1,151 HUEH patients were involved in a passenger car accident. In one of the crashes, the airbag operated, and the belted driver received 2 sutured eye lid wounds and showed conjunctival sugillation. No permanent eye injuries were recorded during the follow-up. The calculated annual airbag-related eye injury incidence was less than 1/1,000,000 people, 4/100,000 accidents, and 4/10,000 injured occupants. CONCLUSIONS: Airbag-related eye injuries occurred very rarely in car accidents in cases where the occupant survived and the restraint system was appropriately used. Spectacle use did not appear to increase the risk of eye injury in restrained occupants.

Peripheral hypertrophic subepithelial corneal degeneration - clinical and histopathological features.

PURPOSE: To refine the diagnostic criteria for peripheral hypertrophic subepithelial corneal degeneration (PHSD) and characterize its clinical phenotype, histopathology and immunohistochemical features. METHODS: Diagnostic criteria were refined on the basis of literature data. Fourteen patients (13 women and one man; median age 52 years, range 33-66) were identified based on these criteria. Keratectomy specimens were evaluated via routine and immunohistochemical stainings. The main outcome measures were symptoms, clinical phenotype, immunological status and histopathologic results. RESULTS: We defined the diagnostic criteria of typical PHSD as elevated circumferential and perilimbal subepithelial fibrosis with focal superficial corneal neovascularization, which were supported by female sex (93%), bilaterality (86%), the centre being in the upper quadrants (81%) and irregular astigmatism of two dioptres or more. The typical symptoms were reduced vision (86%) and the symptoms of ocular surface disease (64%). Light microscopy showed fibrosis with abundant collagen deposition but no inflammation in all patients. An immunohistochemical analysis of nine patients showed uniform staining for vimentin in three distinct types of fibroblasts in variable proportions: keratocyte-like cells that were positive for CD34, myofibroblasts that were positive for smooth muscle actin (SMA) and fibroblasts that were negative for CD34 and SMA. Small numbers of CD68-positive macrophages were also found. CONCLUSIONS: Peripheral hypertrophic subepithelial degeneration is characteristic of middle-aged women, in whom it is typically a bilateral idiopathic degeneration of the cornea associated with ocular surface disease and reduced vision. The fibrotic lesions probably undergo remodelling, inducing changes in corneal contour. A smouldering low-grade inflammation favouring low TGF-ß1 concentrations is postulated as the primary pathological process leading to PHSD.

Peripheral hypertrophic subepithelial corneal degeneration: characterization, treatment and association with human leucocyte antigen genes.

PURPOSE: To evaluate the efficacy of keratectomy in treating irregular astigmatism caused by peripheral hypertrophic subepithelial corneal degeneration (PHSD) and to study the possible underlying immunological risk factors. MATERIALS AND METHODS: Patients (14 eyes) with diagnosed PHSD were treated with superficial keratectomy with or without the assistance of phototherapeutic keratectomy (VisX S4; VisX Inc., Santa Ana, CA, USA). Thirteen patients were subjected to analysis of human leucocyte antigen (HLA) genes, complement C4 gene numbers and total plasma immunoglobulin levels. Immunological risk factors between patients and a control group comprising 150 individuals were compared. RESULTS: The mean preoperative best spectacle corrected visual acuity (BCVA) improved from 0.16 ± 0.22 (LogMAR scale range 0-0.7) to 0.06 ± 0.13 (-0.1-0.4) (p < 0.01). The mean preoperative astigmatism decreased significantly from 3.8 ± 2.1 D (range 1.2-8.2) to 2.1 ± 1.4 (range 0.6-5.0, p = 0.02) based on corneal topography. The HLA-B*44 allele and the ancestral haplotype (AH) 8.1 were found significantly more often in PHSD patients than in controls (both p = 0.03). No differences in the C4 genes were found. CONCLUSIONS: Astigmatism secondary to PHSD can be effectively treated with keratectomy. Peeling of the fibrotic tissue reduced astigmatism and improved visual performance. We suggest that HLA-B*44 allele and AH 8.1 haplotype are immunological factors predisposing to the development of PHSD. The consequent disruption/alteration of the limbal barrier may lead to corneal peripheral fibrous formation inducing astigmatism.

Refractive surgery in anisometropic adult patients induce plastic changes in primary visual cortex.

PURPOSE: To prospectively study the effect of refractive surgery in the primary visual cortex of adult anisometropic and isometropic myopic patients. METHODS: Two anisometropic and two isometropic myopic patients were examined with multifocal functional magnetic resonance imaging technique (mffMRI) before refractive surgery and at 3, 6, 9 and 12 months postoperatively. Two controls without refractive surgery were also examined with mffMRI in the beginning and in the end of the study. Anisometropic patients had only their more myopic eye operated to correct the anisometropia. The myopic isometropic patients had their both eyes operated. RESULTS: Operated anisometropic eyes showed 65% reduced amount of active voxels in foveal data at 12 months postoperatively compared with the preoperative situation. In unoperated anisometropic eyes, the corresponding value was 86% and in myopic patients and controls 31% and 1%, respectively. To confirm this finding, the number of activated voxels representing the innermost ring of the stimulus was also calculated, and an exactly similar phenomenon was encountered in the anisometropic patients. Both anisometropic patients improved the best-spectacle-corrected visual acuity in the operated eye after refractive surgery. CONCLUSION: Our results suggest that plastic changes may take place in the primary visual cortex of anisometropic adult patients after refractive surgery.

Long-term outcome of central toxic keratopathy after photorefractive keratectomy.

PURPOSE: To describe long-term postoperative results of 5 eyes that had central toxic keratopathy after photorefractive keratectomy (PRK). METHOD: In a period of 2 months, 74 eyes were subjected to refractive surgery (21 by PRK and 53 by laser in situ keratomileusis) in 2006. Laser ablations were performed with a VISX S4 (VISX, Santa Ana, CA) excimer laser. Five eyes of 5 different patients in the PRK group experienced a corneal stromal thinning associated with a central opacification (haze), hyperopic shift, and central striae in the first postoperative week. Follow-up examinations were at 1 month and at 2, 6, and 12 months and included uncorrected visual acuity, best spectacle-corrected visual acuity (BCVA), manifest refraction, biomicroscopy, and ultrasound pachymetry. At the last follow-up, confocal microscopy was performed in 3 eyes. RESULTS: Corneal thickness measured by ultrasound pachymetry at the first month postoperatively showed an unexpected stromal thinning of 48 ± 39 µm (range, 19-116 µm) compared with the expected postoperative value. At the last postoperative follow-up, corneal thickness had gained 44 ± 22 µm (range, 20-80 µm) compared with the thickness obtained at 1 month. Uncorrected visual acuity, BCVA, haze, and corneal thickness improved in the first postoperative months and stabilized after 6 months. CONCLUSIONS: Central toxic keratopathy is not related to laser in situ keratomileusis (LASIK) only. The presence of 5 cases after PRK in a short period (2 months) associated with a period of simultaneous change of both postoperative medications and postoperative bandage lens practice suggests a link with an unknown pharmacological response leading to stromal dehydration.

Corneal sensitivity in diabetic patients subjected to retinal laser photocoagulation.

PURPOSE: To determine the changes in corneal sensitivity to different stimulus modalities in diabetes mellitus (DM)1 and DM2 patients with retinopathy, and to explore whether argon laser photocoagulation exacerbates sensitivity loss in diabetic patients. METHODS: Corneal sensitivity to different modalities of stimulus was determined in one randomized eye in 52 patients with DM1 (n = 35) or DM2 (n = 17), and in 27 healthy subjects. Medical history was obtained from all the patients, including age, sex, time from DM diagnosis, type of diabetes, time from onset of retinopathy, type of diabetic retinopathy, and type of argon laser treatment. Corneal sensitivity was determined using a gas esthesiometer. Mechanical, chemical, and thermal (heat and cold) stimuli were applied on the central cornea. RESULTS: Sensitivity thresholds to selective mechanical, chemical, and cold stimulation were significantly higher in DM patients compared to controls. Sensitivity threshold to mechanical and chemical stimuli was higher in DM2 than in DM1 patients. In DM1 patients, mechanical threshold increased with time after DM diagnosis. No correlation was found between sensitivity thresholds to chemical or thermal stimulation and the age of the patient, type of retinopathy, or time from its diagnosis. Laser treatment generated a further impairment of corneal sensitivity. CONCLUSIONS: Corneal sensitivity to mechanical, chemical, and thermal stimulation is decreased in DM patients, suggesting that diabetes affects homogeneously the different types of sensory neurons innervating the cornea. Corneal sensitivity appears to be more disturbed in DM2 than in DM1. Laser treatment of DM patients generates a further impairment in corneal sensitivity, probably as the result of physical damage to ciliary nerves.

Long-term follow-up of photorefractive keratectomy for myopia: Comparative study of excimer lasers.

PURPOSE: To compare the long-term results of photorefractive keratectomy (PRK) for low to moderate myopia performed using a broad-beam laser system or a scanning-slit laser system. SETTING: Department of Ophthalmology, University of Helsinki, Helsinki, Finland. DESIGN: Case-control study. METHODS: This follow-up study comprised eyes with myopia (-1.25 to -7.00 diopters [D]) or myopic astigmatism (astigmatism lower than -2.50 D) corrected by PRK using a broad-beam (Visx) or scanning-slit (Nidek) laser. Follow-up included a visit at 3 months and at more than 8 years. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest refraction were recorded. RESULTS: The broad-beam group comprised 27 eyes and the scanning-slit group, 34 eyes. At the last postoperative follow-up, the UDVA was 0.0 or better in 55% of eyes in the broad-beam group and 65% of eyes in the scanning-slit group. The CDVA was 0.0 or better in all eyes in the broad-beam group and 96% of eyes in the scanning-slit group. Regarding predictability, 48% and 73% of the eyes, respectively, were within ±0.50 D of the intended spherical equivalent refraction. There were no statistically significant differences between the 2 laser groups in any preoperative or postoperative parameter. CONCLUSION: There were no significant differences in UDVA, CDVA, or SE after PRK for low to moderate myopia between the broad-beam laser system and the scanning-slit laser system. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Altered expression of matrix metalloproteinases and their tissue inhibitors as possible contributors to corneal droplet formation in climatic droplet keratopathy.

PURPOSE: Climatic droplet keratopathy (CDK) is an acquired corneal disease characterized by progressive scarring of the cornea. In several corneal diseases, matrix metalloproteinases (MMPs) are upregulated during the degradation of epithelial and stromal tissues. We investigated the levels, degree of activation and molecular forms of MMP-2, MMP-9, MMP-8 and MMP-13 and their tissue inhibitors TIMP-1 and TIMP-2 in tear fluid of patients with CDK. METHODS: Seventeen CDK patients and 10 controls living in Argentine Patagonia received a complete eye examination, and MMPs and TIMP-1/2 were determined by immunofluorometric assay (IFMA), gelatin zymography and quantitative Western immunoblot analysis in tear samples. RESULTS: The MMPs were detected mostly in their latent forms. The levels of MMP-9 and MMP-2 were found to be significantly elevated in CDK patients, whereas latent and active MMP-8 levels were significantly enhanced in controls. There was no significant difference in the level of MMP-13. TIMPs were found as part of complexes, and the TIMP-1 levels were significantly lower in patients than controls. CONCLUSION: Elevated MMP-2 and MMP-9 levels have been implicated in the failure of corneal re-epithelialization, and enhanced MMP-2 and MMP-9 levels in CDK patients suggest that these MMPs may play a role in corneal scarring in CDK. Elevated levels of MMP-8 suggest a defensive role for this MMP in inflammatory reactions associated with recurring corneal traumas. Decreased expression of TIMP-1 in CDK patients suggest deficient antiproteolytic shield likely to render the corneas of CDK patients vulnerable to enhanced MMPs. Overall, these data suggest a mechanistic link between MMPs and TIMP-1 level in cornea and tears with corneal scarring in CDK.

Laser refractive correction of myopia in visually impaired patients improves visual acuity.

PURPOSE: To retrospectively evaluate the visual and refractive outcome of visually impaired adults treated with refractive surgery (photorefractive keratectomy or laser-assisted in situ keratomileusis). METHODS: We searched a refractive surgery database comprising 1716 mildly visually impaired patients [best spectacle-corrected visual acuity (BSCVA) on a logMAR scale ≤ -0.1 (Snellen ≤ 0.8)] who had undergone either PRK or LASIK (n = 96). PRK patients who had visits at 5-7, 8-13 and 14-24 months postoperatively were selected. Eleven patients and nine PRK control myopic patients were found (cohort 1). From the same database, 41 visually impaired patients and 54 controls who had a postoperative control at 14-24 months postoperatively were chosen. These patients formed cohort 2. RESULTS: Preoperatively, in cohort 1, the mean BSCVA on a logMAR scale was -0.15 ± 0.13 (Snellen 0.73 ± 0.16) in visually impaired patients and 0.04 ± 0.02 (Snellen 1.11 ± 0.17) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.05 ± 0.04 (Snellen 1.13 ± 0.10) in visually impaired patients and 0.05 ± 0.08 (Snellen 1.13 ± 0.21) in control patients. In cohort 2, preoperatively the mean BSCVA on a logMAR scale was -0.15 ± 0.12 (Snellen 0.74 ± 0.14) in visually impaired patients and 0.01 ± 0.03 (Snellen 1.04 ± 0.10) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.02 ± 0.07 (Snellen 1.06 ± 0.16) in visually impaired patients and 0.06 ± 0.06 (Snellen 1.15 ± 0.16) in control patients. CONCLUSION: Refractive surgery improves BSCVA in visually impaired patients, possibly through plastic changes in the visual cortex. Consequently, refractive surgery may be used successfully for the treatment of visually impaired adults to enhance their visual acuity.

Selective changes in human corneal sensation associated with herpes simplex virus keratitis.

PURPOSE: To determine corneal sensitivity to selective mechanical, chemical, and thermal (heat and cold) stimulation in patients with a history of herpes simplex virus (HSV) keratitis. METHODS: Corneal sensitivity to different modalities of stimulus was determined in both eyes of 16 patients with unilateral HSV keratitis diagnosed 1 to 12 months before the study. On slit lamp examination, 13 HSV-affected eyes showed corneal scarring or opacities, and three had no signs of previous keratitis. Corneal sensitivity was determined with the Belmonte gas esthesiometer. Mechanical, chemical, heat, and cold stimuli were applied on the central cornea. Eyes from 10 healthy subjects served as controls. RESULTS: In all control and contralateral eyes, selective mechanical, chemical, heat, and cold stimulation evoked sensations of subjective intensity proportional to the magnitude of the applied stimulus. In one HSV patient, the affected cornea was unresponsive to all types of stimuli, four lost only corneal sensitivity to mechanical stimulation, and three lost only sensitivity to heat. Mechanical (P<0.005) and heat (P<0.05) thresholds were raised in HSV eyes, whereas thresholds for CO2 were not modified. Also, HSV subjects identified poorly the intensity of mechanical, chemical, and heat stimuli, whereas sensitivity to cold stimulation was unaffected. CONCLUSIONS: In eyes that had had HSV keratitis, corneal sensitivity to mechanical forces and heat was significantly impaired, suggesting that axonal damage and/or altered expression of membrane ion channels involved in transduction and membrane excitability affects primarily the mechano- and polymodal nociceptor terminals. Corneal cold-sensitive terminals remain largely unaffected.

Seven-year follow-up of LASIK for myopia.

PURPOSE: To assess the long-term refractive results, subjective parameters, and late sequelae of LASIK. METHODS: A retrospective follow-up study was conducted on 38 eyes of 21 patients (17 with bilateral treatment and 4 with unilateral treatment) who had LASIK surgery between 1999 and 2000. Laser ablations were done with an excimer laser (VISX STAR and STAR S2). Follow-up was 2 months, 2 years, and > 7 years postoperatively. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, indirect ophthalmoscopy, and wavefront analysis were measured at the last follow-up and a questionnaire was answered. RESULTS: Postoperatively, BSCVA < or = 0.0 (logMAR) was obtained in 91%, 100%, and 89% of eyes at 2 months, 2 years, and at last follow-up, respectively. Postoperative spherical equivalent refraction within +/- 0.50 diopters (D) was obtained in 75%, 63%, and 42% of eyes at 2 months, 2 years, and 7 to 8 years, respectively. At 2 months and 2 years, 83% of eyes were within +/- 1.00 D, which decreased to 42% at 7 to 8 years. Mean spherical equivalent refraction at 2 months was -0.41 D, at 2 years -0.57 D, and at 7 to 8 years continued to decrease to -1.38 D. Patient satisfaction was high--100% of patients would have LASIK again. CONCLUSIONS: LASIK outcomes tend to shift toward undercorrection over time. Postoperative ectasia was not noted 7 to 8 years after LASIK. All patients were satisfied with the postoperative results although emmetropia was not reached.

Photorefractive keratectomy retreatment after LASIK.

PURPOSE: To study the results of late photorefractive keratectomy (PRK) in corneas originally subjected to LASIK. METHODS: Seven eyes of seven patients who had LASIK for myopia were retreated with PRK at least 2 years after LASIK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, and haze were evaluated before and after LASIK and after retreatment by PRK. RESULTS: Photorefractive keratectomy retreatment improved BSCVA in six (86%) of seven eyes, and one (14%) eye showed no changes. None of the eyes lost lines of BSCVA. Five of seven eyes developed mild haze, which disappeared before the last postoperative follow-up. CONCLUSIONS: Photorefractive keratectomy retreatment performed at least 2 years after LASIK can improve visual acuity. We hypothesize that LASIK-induced corneal nerve damage disturbs corneal wound healing by increasing the tendency for development of haze.

Observational failures/distraction and disease attack/incapacity as cause(s) of fatal road crashes in Finland.

OBJECTIVE: To study the incidence of health-related conditions and observational failures/distraction (OFD) as an immediate cause for fatal motor vehicle accidents (FMVA) and to correlate them with driver's age. METHODS: Retrospective study of all FMVA in Finland secondary to OFD from January 1995 to December 2005 and FMVA secondary to a disease attack/incapacity (DA) from January 2003 to December 2004. The data were based on the final investigation reports of the Finnish Motor Insurers' Centre. The cases were categorized into the three following groups: 1) vehicle crashes due to OFD of the driver, 2) pedestrian-vehicle accidents due to the driver's OFD, and 3) pedestrian-vehicle accidents due to the pedestrian's OFD. In the second part, 54 autopsy reports from FMVA resulting from a DA of the driver between the years 2003-2004 were revisited and the health-related causes of the accident were investigated. RESULTS: Oldest age group (> 65 years) had the highest prevalence of FMVA secondary to an OFD. We estimated that in 20-30% of all FMVA affecting subjects > 65 years an impairment of cognitive functions might have played a role. Analysis of the DA that the inspection teams had concluded to have been the immediate risk factor for the FMVA revealed that these accidents accounted for 10.3% of all FMVA in 2003-2004. Cardiovascular diseases were most often involved. CONCLUSIONS: OFD as an immediate cause of FMVA began to play a role from the age of 60 years onwards. The role of health conditions as a cause of FMVA was higher than expected. Cardiovascular disease (70%) was found to be the leading medical condition that inhibited the driving task among the DA related to FMVA in Finland.

Excimer laser refractive correction of myopia after episcleral buckling for rhegmatogenous retinal detachment.

PURPOSE: To evaluate the long-term effects of excimer laser treatment for ametropia after surgical treatment of rhegmatogenous retinal detachment (RRD) with scleral buckles. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: Ten patients (10 eyes) who had 1 or more surgeries for RRD followed by refractive surgery for myopia were retrospectively enrolled in this study and were examined after excimer laser refractive surgery. Photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) was performed using a Star S2 excimer laser system (Visx). The best spectacle-corrected visual acuity (BSCVA), refraction, degree of anisometropia, and topographical changes were evaluated before and after the surgeries. RESULTS: All patients were free of asthenopic symptoms after refractive surgery. At the end of the follow-up, a mean of 67 months +/- 14 (SD) after refractive surgery, 6 patients were within +/-1.0 diopter of the intended correction. Compared with previously reported cohorts of myopic patients, the achieved refraction in patients who previously had a scleral buckling procedure was worse. The postoperative refraction was stable, and corneal topography did not show induced scar formation, keratectasia, or irregular astigmatism. After refractive surgery, the BSCVA improved 1 Snellen line in 3 patients and 2 lines in 1 patient. One patient lost 1 Snellen line and another patient lost 2 lines. Four patients showed no changes. New retinal complications were not observed. CONCLUSIONS: In the long-term, PRK and LASIK were safe methods for the treatment of myopia in RRD patients after scleral buckling. The predictability of myopic LASIK/PRK may be worse than generally reported in myopic cohorts.

Improvement of visual acuity following refractive surgery for myopia and myopic anisometropia.

PURPOSE: To test the hypothesis that anisometropic adults without significant amblyopia suffer from mild visual impairment probably due to aniseikonia, which might be improved by corneal refractive surgery. METHODS: Fifty-seven patients presenting with myopic anisometropia > or = 3.25 diopters (D) and 174 myopic controls appropriate for refractive surgery were included. Photorefractive keratectomy (PRK) or LASIK was performed on 57 anisometropic eyes. As 43 of the 174 myopic control patients had bilateral surgery, PRK or LASIK was performed on 217 myopic control eyes. Best spectacle-corrected visual acuity (BSCVA), refraction, and refractive correction were measured preoperatively and at 1, 3, 5 to 7, 8 to 13, and 25 months following surgery. RESULTS: Preoperative mean spherical equivalent was -7.20 +/- 2.40 D for anisometropic patients and -6.40 +/- 1.90 D for myopic patients. At 8 to 13 months postoperatively, when 23 (40%) anisometropic eyes and 94 (43%) myopic eyes were examined, the mean spherical equivalent refractions were -0.80 +/- 1.60 D and -0.30 +/- 0.60 D, respectively. Preoperatively, the mean BSCVA on a logMAR scale was -0.0143 +/- 0.0572 (Snellen 0.98 +/- 0.12) in the anisometropic group and 0.0136 +/- 0.0361 (Snellen 1.04 +/- 0.09) in the control group (P = .001). Eight to 13 months postoperatively, these values were 0.0076 +/- 0.0659 (Snellen 1.03 +/- 0.15) and 0.0495 +/- 0.0692 (Snellen 1.13 +/- 0.18) and this difference remained statistically significant (P = .012). For the myopic patients, the improvement in BSCVA reached almost maximum at 3 months, and this improvement was found to be highly significant 3 months after surgery (P = .001). The improvement in BSCVA was significantly slower for anisometropic patients and became statistically significant only after 8 to 13 months postoperatively (P = .041). CONCLUSIONS: Anisometropia reduces visual acuity in the more myopic eye and can be at least partially reversed by refractive correction. The slower improvement in BSCVA for anisometropic patients suggests plastic changes in the visual cortex following refractive surgery.

Phototherapeutic keratectomy for epithelial irregular astigmatism: an emphasis on map-dot-fingerprint degeneration.

PURPOSE: To study the changes in irregular astigmatism in patients with recurrent corneal erosion syndrome due to map-dot-fingerprint degeneration and to demonstrate that both symptomatic and asymptomatic map-dot-fingerprint degeneration/recurrent corneal erosion syndrome may be related to irregular astigmatism, which can effectively be corrected by phototherapeutic keratectomy (PTK) or standard spherical photorefractive keratectomy (PRK). METHODS: Eleven eyes with irregular astigmatism related to map-dot-fingerprint degeneration/recurrent corneal erosion syndrome with and without changes at the slit-lamp microscope were treated with PTK or spherical PRK, which was performed with a VISX S2 or S4 excimer laser. All eyes underwent videokeratography performed pre- and postoperatively using either the Tomey TMS-2N Topographic Modeling System or EyeSys Technologies Corneal Analysis System 2000. RESULTS: Mean pre- and postoperative best spectacle-corrected visual acuity (BSCVA) was -0.18 +/- 0.14 logMAR and 0.04 +/- 0.04 logMAR, respectively. This improvement in BSCVA was statistically significant. The mean gain in Snellen lines was 2.4 +/- 2.1. Preoperative corneal videokeratography showed irregular astigmatism with an elevation pattern that was corrected in all eyes despite the fact that no astigmatic photorefractive correction was performed. CONCLUSIONS: Following PTK, eyes with irregular astigmatism related to map-dot-fingerprint degeneration showed significant improvement in BSCVA and correction of irregular astigmatism as revealed by videokeratography. This study shows that irregular astigmatism can be exclusively of epithelial origin and in some eyes abnormal corneal epithelium may create optical aberrations. This possibility should be taken into account when, for example, wavefront-guided stromal photoablation procedures are being planned.

Acinetobacter and Staphylococcus aureus ulcerative keratitis after laser in situ keratomileusis treated with antibiotics and phototherapeutic keratectomy.

PURPOSE: To report a method of treatment for through-the-flap multibacterial ulcerative keratitis after laser in situ keratomileusis (LASIK). METHODS: Bacterial ulcerative keratitis after LASIK was treated with topical and systemic antibiotics followed by flap lifting, cleaning, and phototherapeutic keratectomy (PTK). Follow-up examinations included in vivo confocal microscopy, corneal topography, and wavefront analysis. RESULTS: Rapid recovery of the ulcerative keratitis was observed after flap lifting and cleaning of the interface and PTK combined with topical and systemic antibiotics. Two years postoperatively, corneal topography showed a slight depression of the ulcer area and decentration of the photoablation. Wavefront analysis revealed an irregular scan with a pronounced coma-like aberration, which with a wavefront-guided custom test lens correction provided 20/16 visual acuity. CONCLUSIONS: Ulcerative bacterial keratitis is a possible sight-threatening complication of LASIK refractive surgery. Lifting and rinsing the flap combined with cleaning of the flap interface with PTK may be helpful in these conditions when regression of the ulcer does not occur with topical and oral antibiotic treatment.

Interaction of purified tear lipocalin with lipid membranes.

PURPOSE: The principal lipid-interacting protein in human tears has been reported to be tear lipocalin (Tlc). Tlc has been suggested to scavenge harmful lipophilic substances from the corneal epithelium and to maintain the integrity of the anterior tear film lipid layer by binding and releasing lipid(s) that are accommodated within the protein. Although lipids can be extracted from Tlc, it is still unclear whether Tlc can actually bind to lipid membranes and accept membrane lipids and whether it possesses lipid transfer activity. The purpose of this study was to explore the interaction of Tlc with neutral, anionic, and cationic lipid membranes and to assess the potential of Tlc to facilitate the transfer of either polar or neutral lipids in a lipid transfer assay. METHODS: The binding of Tlc to lipid membranes was assessed by a monolayer technique and fluorescence spectroscopy. The polar lipid transfer activity of Tlc was assessed with a radiometric assay based on the transfer of (14)C-phosphatidylcholine (PC) from PC-liposomes to HDL(3). The neutral lipid transfer activity of Tlc was assayed by measuring the transfer of radioactive cholesteryl ester from LDL to HDL(3). RESULTS: Purified Tlc showed significant surface activity as evidenced by an increase in surface pressure at the air-buffer interface. Likewise, it interacted actively with neutral, anionic, and cationic lipid monolayers, as evidenced by an equal increase in surface pressure despite the surface charge. Enhanced quenching of the single tryptophan residue of Tlc by pyrene and I(-) anion suggested that different protein domains are involved in the interaction of Tlc with oppositely charged lipid membranes. Finally, radiometric assays revealed that Tlc does not possess any neutral or polar lipid transfer activity between lipid vesicles or/and lipoproteins. CONCLUSIONS: Tlc interacted with lipid membranes composed of neutral, cationic, or anionic membranes, which supports a role for Tlc in the maintenance of the tear film interfaces. Tlc did not show any neutral or polar lipid transfer activity whatsoever. The findings suggest that the notion of the role of Tlc as the major lipid-transferring protein in human tears should be revised.

Phospholipid transfer protein is present in human tear fluid.

The human tear fluid film consists of a superficial lipid layer, an aqueous middle layer, and a hydrated mucin layer located next to the corneal epithelium. The superficial lipid layer protects the eye from drying and is composed of polar and neutral lipids provided by the meibomian glands. Excess accumulation of lipids in the tear film may lead to drying of the corneal epithelium. In the circulation, phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein (CETP) mediate lipid transfers. To gain insight into the formation of tear film, we investigated whether PLTP and CETP are present in human tear fluid. Tear fluid samples were collected with microcapillaries. The presence of PLTP and CETP was studied in tear fluid by Western blotting, and the PLTP concentration was determined by ELISA. The activities of the enzymes were determined by specific lipid transfer assays. Size-exclusion and heparin-affinity chromatography assessed the molecular form of PLTP. PLTP is present in tear fluid, whereas CETP is not. Quantitative assessment of PLTP by ELISA indicated that the PLTP concentration in tear fluid, 10.9 +/- 2.4 microg/mL, is about 2-fold higher than that in human plasma. PLTP-facilitated phospholipid transfer activity in tears, 15.1 +/- 1.8 micromol mL(-)(1) h(-)(1), was also significantly higher than that measured in plasma. Inactivation of PLTP by heat treatment (+58 degrees C, 60 min) or immunoinhibition abolished the phospholipid transfer activity in tear fluid. Size-exclusion chromatography of tear fluid indicated that PLTP eluted in a position corresponding to a size of 160-170 kDa. Tear fluid PLTP was quantitatively bound to Heparin-Sepharose and could be eluted as a single peak by 0.5 M NaCl. These data indicate that human tear fluid contains catalytically active PLTP protein, which resembles the active form of PLTP present in plasma. The results suggest that PLTP may play a role in the formation of the tear film by supporting phospholipid transfer.