1/139. fluorescein test for the detection of striae in the corneal flap after laser in situ keratomileusis.PURPOSE: To report a technique for detecting striae in the corneal flap after laser in situ keratomileusis. methods: fluorescein dye was instilled in the eye, and the patient was asked to blink. The tear film was examined at the slit lamp with the cobalt filter 1 or 2 seconds after blinking. RESULTS: The uneven pattern of pooling in the tear film was a sensitive indicator of the presence of striae in the flap. CONCLUSION: This technique may be useful in detecting minimal striae in the corneal flap in patients with unexplained suboptimal visual acuity after laser in situ keratomileusis.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
2/139. Ultrasonographically guided injection of corticosteroids for the treatment of retroseptal capillary hemangiomas in infants.PURPOSE: Injection of corticosteroids is a well-documented and successful mode of treatment for periorbital capillary hemangiomas. Because of the greater potential risk involved with retrobulbar injections, no prior study has described this treatment for tumors located behind the orbital septum. Although retroseptal intraorbital capillary hemangiomas comprise only 7% of all adnexal capillary hemangiomas, complications such as optic nerve compression or astigmatism may necessitate treatment. methods: Three patients with deep orbital hemangiomas that caused vision-threatening complications were treated with intralesional injections of triamcinolone and betamethasone. Orbital injection was performed with use of real-time ultrasonographic guidance of the needle. This technique was valuable in providing continuous, accurate, and safe advancement of the needletip in the orbit to avoid the globe and orbital walls. ultrasonography also permitted precise placement of the needle tip within the tumor and visualization of the injected material. RESULTS: Significant improvement was demonstrated in all cases on the basis of both ultrasonographic measurements and regression of clinical manifestations such as astigmatism, chemosis, proptosis, and optic nerve pallor. No complications were noted. CONCLUSION: Intralesional injection of corticosteroids to treat retroseptal and retrobulbar capillary hemangiomas was found to be a safe and effective treatment modality in our patients. Positioning of the injecting needle was guided by ultrasonography.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
3/139. Sterile interface keratitis after laser in situ keratomileusis: three episodes in one patient with concomitant contact dermatitis of the eyelids.PURPOSE: To illustrate a case in which sterile interface keratitis after laser in situ keratomileusis (LASIK) occurred concomitantly with an allergic contact dermatitis of the eyelids. methods: Retrospective case review. RESULTS: Resolution of the interface keratitis and dermatitis occurred following an intense course of topical corticosteroids and brief course of oral corticosteroids. Despite an attempt to eliminate potential causes, the same patient developed interface keratitis in the fellow eye following both the initial LASIK and an enhancement, in which no microkeratome was used. Intense treatment with both topical and oral corticosteroids led to a final uncorrected visual acuity of 20/20 in the right eye and 20/25 2 in the left eye. CONCLUSION: The etiology and mechanism of sterile interface keratitis after LASIK are unknown, but are probably multifactorial. The concomitant contact dermatitis reaction may indicate a common immune mechanism.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
4/139. Overcorrected radial keratotomy treated with posterior chamber phakic intraocular lens and laser thermal keratoplasty.PURPOSE: Modern refractive surgery is effective in a large majority of cases in achieving a good first time result. Some attempts at correction, however, are less successful and require subsequent revision. methods: A case of secondary hyperopic astigmatism ( 0.75 1.50 x 45 degrees) is reported in a patient who had undergone radial keratotomy for myopia of -6.00 0.75 x 90 degrees, 8 years previously. Preoperative uncorrected visual acuity was 20/120 improving to 20/20 with correction. Further refractive procedures were performed including arcuate keratotomy, posterior chamber phakic intraocular lens implantation and laser thermal keratoplasty to improve the uncorrected visual result. RESULTS: Final uncorrected visual acuity was 20/40, spectacle-corrected visual acuity was 20/20 with a manifest refraction of 0.50 1.00 x 40 degrees. CONCLUSIONS: This case demonstrates how the consecutive application of several procedures can successfully refine an initially unsatisfactory refractive result. The potential for reduced predictability and additional complications with each procedure should not be forgotten.- - - - - - - - - - ranking = 4keywords = visual (Clic here for more details about this article) |
5/139. Implantation of a toric poly(methyl methacrylate) intraocular lens to correct high astigmatism.A 57-year-old man experienced a decrease in visual function because of cataract formation. Corneal astigmatism was 13.4 diopters (D) because he had had a penetrating keratoplasty 27 years before. cataract surgery was planned, and biometric data for toric intraocular lens (IOL) implantation were collected for the manufacture of a custom IOL. After phacoemulsification, a toric poly(methyl methacrylate) (PMMA) IOL of 19.0 D spherical and 12.0 D cylindrical power was implanted via a sclerocorneal tunnel incision. Three months postoperatively, corneal astigmatism was 14.3 D and best corrected visual acuity (BCVA), 20/25. Postoperative refraction ( 1.5 -3.0 x 90) and BCVA remained stable for 7 months. No significant IOL rotation was observed. Implantation of a toric PMMA IOL corrected high corneal astigmatism. Toric IOL technology with high cylindrical power allows enhancement of IOL surgery.- - - - - - - - - - ranking = 2keywords = visual (Clic here for more details about this article) |
6/139. A new concept for the correction of astigmatism: full-arc, depth-dependent astigmatic keratotomy.OBJECTIVE: The purpose of this study is to introduce and evaluate a new concept in astigmatic keratotomy (AK) named full-arc, depth-dependent AK (FDAK). DESIGN: Noncomparative interventional case series. PARTICIPANTS: FDAK was performed on a total of 37 eyes with regular astigmatism; of these, 16 eyes received FDAK alone, and 21 eyes received FDAK combined with cataract surgery. methods: corneal topography was used to divide the cornea into two discreet regions of "steep" and "flat." Then, paired arcuate incisions, 90 degrees in length, were placed along the full arc of the steep area. The level of astigmatic correction was controlled by varying the incision depth from 40% to 80% on the basis of a provisional nomogram developed by the authors. MAIN OUTCOME MEASURES: Keratometries, corneal topographies, and visual acuities were measured. RESULTS: The FDAK alone group showed a significant improvement from a preoperative corneal astigmatism of 2.90 /- 0.78 diopters (D) to a postoperative value of 0.89 /- 0.52 D. The "combined" group also showed significant improvement from a preoperative corneal astigmatism of 2.97 /- 1.01 D, to a postoperative value of 1.02 /- 0.45 D. The deviation of achieved correction from attempted correction using vector analysis was between 1.37 D of undercorrection and 0.98 D of overcorrection, with 91.9% of cases within the range of /- 1.0 D. Slight oblique change caused by axis deviation was observed in seven cases. Both uncorrected and corrected visual acuity showed statistically significant improvement. No serious complications were encountered. CONCLUSIONS: Controlling the level of correction by varying the incision depth allowed the surgeon to use long incisions (90 degrees in length in regular astigmatism) covering the entire steep area, minimizing the undesirable changes induced by conventional deep and narrow incision AK and resulting in an ideal corneal sphericity after surgery. FDAK enabled the surgeon to accurately control the level of astigmatic correction with minimal risk of corneal perforation.- - - - - - - - - - ranking = 2keywords = visual (Clic here for more details about this article) |
7/139. Topography-controlled excimer laser photorefractive keratectomy.PURPOSE: To assess whether photorefractive keratectomy (PRK) controlled by videokeratography can successfully treat refractive errors in eyes with corneal irregularities and improve spectacle-corrected visual acuity. methods: In a prospective clinical study, PRK was performed in 10 eyes of 10 patients. Reason for surgery was irregular astigmatism after penetrating keratoplasty, corneal irregularity after corneal scarring, corneal astigmatism in keratoconus, and decentration after myopic and hyperopic PRK. Excimer ablation was controlled by preoperative videokeratography (Orbscan II, Orbtek) using the MEL-70 system from Aesculap Meditec. Follow-up was 6 months. RESULTS: Concerning manifest refraction, the sphere was reduced on average from 1.92 to 0.57 D, 6 months postoperatively. Cylinder changed from -1.95 D on average to -0.30 D at 6 months postoperatively. There was improvement of uncorrected visual acuity of 2 or more lines in 5 eyes and no change in 5 eyes 6 months postoperatively. Spectacle-corrected visual acuity improved in 2 eyes by 2 to 3 lines, in 9 eyes by 1 to 3 lines, and showed no change in 1 eye. CONCLUSION: Videokeratography-controlled PRK improved refractive errors in irregular corneas with improvement of spectacle-corrected visual acuity.- - - - - - - - - - ranking = 4keywords = visual (Clic here for more details about this article) |
8/139. Confocal microscopy of a patient with irregular astigmatism after LASIK reoperations and relaxation incisions.PURPOSE: Laser-assisted in situ keratomileusis (LASIK) is widely used for correcting refractive errors. If the predicted refractive result is not achieved after the first operation, a re-operation can be performed by ablating more stromal tissue after reopening the flap. The goal of this study was to analyze, by using in vivo confocal microscopy, the morphologic changes associated with repeated LASIKs. methods: Clinical examination, computed corneal topography, and real-time in vivo confocal microscopy were performed on both eyes of a 50-year-old patient with induced irregular astigmatism leading to decreased best-corrected vision in the left eye after LASIK. The left cornea had been operated on 5 times (LASIK with two reoperations followed by two relaxing incisions), and the right cornea twice (LASIK with one reoperation). RESULTS: Microfolds at the level of the Bowman's layer and highly reflective particles at the flap interface were observed in both corneas. The subbasal nerve plexus was severed in the left eye. In addition, we identified epithelial material in the flap margin and inside one of the two relaxing incisions placed inferotemporally. CONCLUSION: Repeated LASIKs may stretch the flap and result in microfolding at the Bowman's layer. This and deposition of particles in the flap interface may increase with the number of reoperations, challenging the healing response. Microfolding and occurrence of foreign material in the interface may add to the irregular astigmatism and poor visual outcome after LASIK. Clinical in vivo confocal microscopy offers new possibilities for the assessment of ultrastructural changes after corneal refractive surgery.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
9/139. A mathematical model for laser in situ keratomileusis and photorefractive keratectomy.PURPOSE: The purpose of ablation refractive surgery is to remove the refractive error from the inherently asymmetric aspheric cornea. Although the technique is gaining wide acceptance and popularity, some patients are left with irregular corneas. Our objective was to develop a methodology to analyze corneal shape, reduce the shape to arcs, modify the local arc value to the desired new arc value, and render a new continuous Euclidean surface without discontinuity. methods: The method to reconstruct the corneal surface consists of importing scanner output elevation data points into a computer-aided design (CAD) application to form the surface model. The corneal arc measurements are derived at 5 degrees increments and centered about the Gauss point of symmetry. Each arc is manipulated to adjust the corresponding arc on the proposed corneal surface to reflect the new arc value, correcting for the refractive error. The method determines the amount of corneal tilt and ablation depth at a given diameter required for the refractive error with a smooth transition zone to the base cornea. RESULTS: The case example is a patient who began with a spherical refraction of -8.75 D and after LASIK was emmetropic, but had irregular astigmatism and 20/30 best spectacle-corrected Snellen visual acuity. The proposed mathematical model compares the achieved surface shape to the mathematically planned surface contour. An enhancement procedure to remove the LASIK-induced corneal irregularity was designed. CONCLUSION: A mathematical technique to plan myopic ablative surgery to make the corneal surface regular and symmetric is proposed.- - - - - - - - - - ranking = 1keywords = visual (Clic here for more details about this article) |
10/139. Selective zonal ablations with excimer laser for correction of irregular astigmatism induced by refractive surgery.OBJECTIVE: To demonstrate the safety and efficacy of selective zonal ablations with excimer laser for the correction of irregular astigmatism induced by refractive surgery. DESIGN: Thirty-one eyes of 26 patients. Retrospective and noncomparative case series. methods: The authors reviewed the medical results of the two series of consecutive cases of irregular astigmatism induced by refractive surgery. One group showed a topography map with a defined pattern: decentered ablation, decentered steep central island, central irregularity, and peripheral irregularity. The other group showed an irregular astigmatism without defined pattern. Selective zonal ablation was performed with a broad-beam excimer laser. Laser ablations were adjusted according to the Munnerlyn formula. A phototherapeutic keratectomy (PTK) mode was used in all cases without using viscous masking solution. MAIN OUTCOME MEASURES: Uncorrected visual acuity, best spectacle-corrected visual acuity (BCVA), and Holladay diagnostic summary (Eye Sys 2.000) were considered before and after surgery to obtain the qualitative and quantitative characteristics of the visual acuity and corneal topography. The corneal uniformity index (CUI) was used to evaluate the corneal surface changes induced by the selective zonal ablations in the correction of irregular astigmatism. It proved to be a useful tool in the understanding of astigmatic changes when it is not possible to apply the vector analysis. RESULTS: In group 1, the irregular astigmatism was significantly improved in 96.4% of cases. The CUI was improved from 58 /-0.3% to 87 /-0.8%, P < 0.005 (Student's t-test). The improvement of the BCVA was from 20/40 /-20/100 to 20/25 /-20/100, P < 0.005 (Student's t-test). The results obtained in group 2 were not clinically significant in terms of improvement of CUI and BCVA. CONCLUSIONS: Using the corneal topographic map as a guide, selective zonal ablations with excimer laser can be used to create a more regular corneal surface, when a defined pattern of topographic irregularities can be defined.- - - - - - - - - - ranking = 3keywords = visual (Clic here for more details about this article) |
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