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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., (© 2013 The Authors. Acta Ophthalmologica © 2013 Acta Ophthalmologica Scandinavica Foundation.)

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., (© 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.)

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.

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., (© 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.)

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., (Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

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.

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.

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.

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.

Objective: To evaluate visual performance after unilateral photorefractive keratectomy (PRK) performed for >/=2.75-diopter (D) myopic anisometropia., Design: Prospective observational case series., Participants: Eleven patients exhibiting >/=2.75-D myopic anisometropia appropriate for PRK., Methods: Photorefractive keratectomy was performed on 11 eyes of 11 patients for myopic anisometropia ranging from -2.75 to -9.00 D. Best spectacle-corrected visual acuity (VA), contrast sensitivity (CS), and pattern visual evoked potentials (pVEPs) were measured preoperatively and at 3 and 6 months., Main Outcome Measures: Best spectacle-corrected VA; pVEPs; and CS, measured as the area under the CS curve., Results: Best spectacle-corrected VA increased nonsignificantly 6 months after PRK. A tendency towards decreased latency time of pVEPs for both eyes was observed after PRK. A significant increase in CS occurred after PRK in the operated eye at 6 months, but a tendency toward decreased CS appeared in the unoperated eye at 3 months. Preoperative CS levels, however, were reached at 6 months., Conclusions: The adult central visual system is sensitive to visual deprivation caused by anisometropia. Imbalance between eyes may improve visual performance in the more emmetropic eye. Anisometropia appears to reduce visual performance in the more myopic eye, but this can probably be reversed by refractive correction.

Purpose: To study the effect of photorefractive keratectomy (PRK) on the concentration of group IIA phospholipase A(2) (GIIAPLA(2)) in tears., Setting: Departments of Ophthalmology and Pathology, University of Turku, Turku, and Helsinki University Eye Hospital, Helsinki, Finland., Methods: Tear samples were collected from 25 eyes of 23 patients (mean age 32.3 years +/- 8.6 [SD]) preoperatively and 2 and 7 days after PRK. The GIIAPLA(2) concentration in the tears was measured by time-resolved fluoroimmunoassay., Results: The GIIAPLA(2) concentration was significantly lower and the tear fluid flow rate significantly higher 2 days after PRK than preoperatively. At 7 days, the GIIAPLA(2) concentration and the tear fluid flow-corrected excretion of GIIAPLA(2) were significantly higher than preoperatively and at 2 days. The tear flow rate was also significantly higher than preoperatively., Conclusions: The GIIAPLA(2) content in tears decreased 2 days after PRK due to dilution of the GIIAPLA(2) content during hypersecretion of reflex tears. Photorefractive keratectomy caused an increase in the tear flow rate, GIIAPLA(2) concentration, and tear fluid flow-corrected excretion of GIIAPLA(2) in tears 7 days after surgery, enhancing the protection of tears against bacterial infections.

Purpose: Matrix metalloproteinases (MMPs) play a central role in the wound-healing process. The objective of this study was to identify and characterize the levels and molecular forms of human tear fluid collagenase-2 (MMP-8) and membrane type 1-MMP (MT1-MMP or MMP-14) in patients who had undergone excimer laser photorefractive keratectomy (PRK) and in healthy subjects. Whether MT1-MMP activates pro-MMP-8 was also determined., Methods: Tear fluid samples were collected with scaled and blunted microcapillaries from healthy control subjects and, on the second postoperative day, from patients who had undergone PRK. Time and the volume collected were registered. Molecular forms and levels of pro and active MMP-8 and MT1-MMP in these samples were determined by Western immunoblot analysis, quantitated by computer scanning. The concentration of MMP-8 was also determined by immunofluorescence assay. The conversion of pure human polymorphonuclear neutrophil (PMN) pro-MMP-8 to the active form by the catalytic domain of MT1-MMP was studied by Western immunoblot analysis., Results: The tear fluid flow was increased after PRK. Tear fluid flow-corrected excretion of MMP-8 was significantly higher in PRK-treated patients, as assessed by immunofluorescence assay and quantitative Western immunoblot analysis. The major MMP-8 species detected in tears of both PRK-treated patients and healthy control subjects represented latent and active 75- and 65-kDa highly glycosylated MMP-8 isoforms. The less-glycosylated 45- to 55-kDa MMP-8 isoform was not detectable. Tear fluid flow-corrected secretion of MT1-MMP was significantly higher in PRK-treated patients. Soluble 80-kDa MT1-MMP immunoreactivities were detected in tears of both healthy control subjects and PRK-treated patients, and may represent a complex captured by tissue inhibitor of metalloproteinase (TIMP)-2. Human PMN pro-MMP-8 was converted to the active form by MT1-MMP, and TIMP-2 prevented this activation., Conclusions: Corneal renewal eventually occurs at a high rate and is affected by the rate of corneal collagen and other matrix protein breakdown. Accordingly, tear fluid MMP-8 and MT1-MMP levels were shown to be constantly high in normal subjects. With PRK, a fast wound-healing process was associated with even higher MMP-8 and MT1-MMP levels and their activation. The results suggest a role for a MMP-8 and MT1-MMP network in the corneal wound-healing cascade. Furthermore, MT1-MMP (MMP-14) seems to activate pro-MMP-8.