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Salomon Esquenazi

Publications and source records attributed to Salomon Esquenazi.

14 recordsLinked to original sources
PubMed2006

Wound-healing response and refractive regression after conductive keratoplasty.

PURPOSE: To characterize the histological changes that occur after conductive keratoplasty (CK) using a rabbit model. SETTING: LSU Eye Center and Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, School of Medicine, New Orleans, Louisiana, USA. METHODS: Conductive keratoplasty was performed on 24 eyes of 12 New Zealand albino rabbits. In each eye, 24 spots were placed in a cross-corneal manner using 3 optical zones at 6.0, 7.0, and 8.0 mm. Eyes were assessed with corneal topography weekly. Rabbits were humanely killed 2, 4, 6, and 8 weeks postoperatively. The eyes were then enucleated and processed for histopathology and immunohistochemical analysis. RESULTS: All eyes showed an initial mean steepening of the corneal curvature of 2.24 diopters (D) 2 weeks postoperatively. Corneal topography revealed a 26%, 36%, and 39% regression of the refractive results at 4, 6, and 8 weeks, respectively. Immunohistochemical analysis demonstrated keratocyte apoptosis, myofibroblast appearance, and upregulation of chondroitin sulfate, MMP-1, and collagen III in the area surrounding the tip in each spot. CONCLUSION: The histological changes that occur after CK may be responsible for the well-established regression of its refractive effect. A better understanding of the wound-healing response after CK is necessary to improve the long-term stability of the procedure.

Actins↗
PubMed2006

Healing process at the flap edge in its influence in the development of corneal ectasia after LASIK.

PURPOSE: Post-laser in situ keratomileusis (LASIK) corneal ectasia is a progressive deformation of the gross corneal anatomy that occurs after surgery. However, this is a rare event even after deep lamellar keratoplasty. We hypothesize that the strength of the lamellar keratoplasty wound is derived from the sutures that enhance the wound edge healing response. This study compares, in a rabbit model, the stability of previously sutured and unsutured microkeratome flaps. METHODS: Unilateral 160-micro m-thick LASIK flaps using a mechanical microkeratome was performed in 20 rabbit eyes. Animals were then divided in two groups: In group A, the flap was left without sutures. In group B, the flap was sutured with 12 interrupted 10/0 nylon stitches that were removed after 3 weeks under general anesthesia. Six weeks after surgery, all rabbits had corneal topographies performed at their baseline intraocular pressure (IOP) (14 mmHg) and at two artificially increased pressures (25 and 45 mmHg) using an anterior chamber maintainer implanted in the inferior limbal area. The animals were humanely euthanized, and immunohistological analysis of the corneas was performed. RESULTS: A delta K1 value, which indicates the difference in the simulated keratometric value at baseline and the one measured at 25 mmHg, was calculated for all eyes. It showed a mean steepening effect of 2.74 D +/- 0.38 D in group A compared with 1.08 D +/- 0.27 D in group B (p < 0.05). Similarly, a delta K2 value, which indicates the difference in the simulated keratometric value at baseline and the one obtained at 45 mmHg, was registered. It showed a mean steepening effect of 3.02 D +/- 0.87 D in group A compared with 0.75 D +/- 0.44 D in group B (p < 0.05). Six weeks after surgery, the peripheral flap interface in group B consisted of 14.3% +/- 4.15% of positive monoclonal mouse anti-alpha smooth muscle actin (alpha-SMA) cells compared with 4.18 +/- 3.76% in group A (p < 0.05). CONCLUSIONS: The addition of sutures in the corneal flap after LASIK appears to reduce the amount of corneal steepening when the IOP is artificially increased up to 25 mmHg in this rabbit model. Our results suggest that an increase in the amount of myofibroblastas induced by the sutures may be responsible for this behavior. Corneal ectasia may be related to the clinically observed lack of corneal wound-healing at the edge of the flap that allows the cornea to bulge. By stimulating a stronger wound-healing response at the edge of the flap, the cornea may better resist steepening under increased IOP conditions and improve the long-term stability of LASIK surgery in borderline thin corneas.

Actins↗
PubMed2005

Comparison of corneal wound-healing response in photorefractive keratectomy and laser-assisted subepithelial keratectomy.

PURPOSE: To evaluate in a rabbit model the differences in cellular and matrix stromal response in low and high attempted corrections between photorefractive keratectomy (PRK) and laser-assisted subepithelial keratectomy (LASEK). SETTING: Louisiana State University Health Sciences Center, Department of Ophthalmology and Neuroscience Center, New Orleans, Louisiana, USA. METHODS: Twenty-four eyes of 12 New Zealand albino rabbits were used. Photorefractive keratectomy was performed in 1 eye and LASEK was performed in the contralateral eye of all rabbits. In 5 animals, a low refractive correction (--3 diopters [D]) was attempted. In the other 5 rabbits, a high refractive correction (--7 D) was attempted. Two rabbits served as controls. The animals were followed for 7 days, after which they were humanely killed. The eyes were enucleated and processed for histopathology and immunohystochemical analysis. RESULTS: All eyes showed an inflammatory response in the anterior stroma adjacent to the ablated area, with greater inflammatory cell infiltration with higher attempted corrections. Similar keratocyte apoptosis was found with low attempted corrections in PRK-treated and LASEK-treated eyes. However, there was a significant increase in keratocyte apoptosis in the PRK group at higher attempted corrections. Increased transformation to myofibroblasts and synthesis of chondroitin sulfate were observed adjacent to the ablated stroma in all eyes. With low corrections, no differences were observed between LASEK-treated and PRK-treated eyes. With higher attempted corrections, there was a significant increase in myofibroblast transformation and chondroitin sulfate synthesis in the PRK group. An irregular and discontinued collagen IV component of the epithelial basement membrane was observed in all PRK-treated and LASEK-treated eyes regardless of the attempted correction. CONCLUSIONS: At higher attempted corrections, LASEK-treated eyes showed less keratocyte apoptosis, myofibroblast transformation, and up-regulation in the synthesis of chondroitin sulfate than PRK-treated eyes. These differences may account for better visual acuities and less stromal haze in higher attempted corrections in LASEK-treated eyes.

Animals↗
PubMed2005

Use of autologous serum in corneal epithelial defects post-lamellar surgery.

PURPOSE: To evaluate the efficacy of an autologous serum treatment of post-LASIK (laser in situ keratomileusis) corneal epithelial defects in a rabbit model. METHODS: Five milliliters blood samples from 10 New Zealand rabbits were obtained by venepuncture. The serum was aseptically separated and diluted with saline solution to 20%. The final preparation was placed into 3-mL bottles with ultraviolet protection and maintained at 4 degrees C. Corneas were de-epithelialized using a 7-mm optical zone marker. A 160-microm thick flap was created in both eyes of all rabbits using an automatic corneal shaper microkeratome. Right eyes were treated with serum drops 6 times per day. Left eyes were treated with preservative-free artificial tears. Vital staining of the ocular surface and the area of corneal epithelial defect was measured daily for 1 week. Rabbits were humanely euthanized at postoperative day 7, and corneas were fixed and sectioned. Hematoxylin and eosin staining and immunohistochemical analysis were performed. RESULTS: Corneas treated with autologous serum had a statistically significant increase in the epithelial healing rate compared with those treated with artificial tears. Serum-treated corneas showed significantly less terminal transferase-mediated dUTP nick-end labeling (TUNEL) staining in the interface, minimal inflammatory cell infiltration, and less induced synthesis of stromal chondroitin sulfate than did corneas treated with preservative-free artificial tears. CONCLUSIONS: Treatment with autologous serum could be an efficient way to provide essential components to the ocular surface in the treatment of post-LASIK epithelial defects. Autologous serum induces faster epithelial healing than do artificial tears, leading to (1) a decrease in keratocyte apoptosis and migration of fibroblasts and myofibroblasts in the wound site, (2) a decrease in the migration of inflammatory cells, and (3) a consequent inhibition of cytokine release. This treatment could improve long-term refractive results post-LASIK.

Animals↗
PubMed2005

Topical combination of NGF and DHA increases rabbit corneal nerve regeneration after photorefractive keratectomy.

PURPOSE: To investigate the effect of nerve growth factor (NGF) in combination with docosahexaenoic acid (DHA) on corneal nerve regeneration in a rabbit model after PRK and correlate the findings with functional tear test. METHODS: Unilateral PRK was performed on 21 New Zealand albino rabbits. Three groups, each consisting of six rabbits, were randomized to receive twice-weekly treatments with DHA, NGF, or NGF plus DHA delivered by collagen shield. A fourth group, the control, received treatment with albumin. Rabbits were observed for 8 weeks, and tear secretion tests were conducted every 15 days. The eyes were prepared for immunostaining. Monoclonal antibodies for class II beta-tubulin, calcitonin gene-related peptide (CGRP), substance P (SP), and Ki-67 were used. Cell nuclei were stained with 4',6'-diamino-2-phenylindole (DAPI). Positive staining areas in relation to total area were calculated with image-analysis software. RESULTS: There were no significant differences in the tear-secretion test results among the four groups. However, none of the eyes treated with NGF plus DHA showed rose bengal staining 30 days after PRK, compared with 50% in the control group and 33% in the DHA-treated group. A higher percentage of Ki-67-positive cells, a marker of cell proliferation, was observed in the DHA plus NGF-and NGF-treated groups compared with DHA alone or the control. Eight weeks after PRK, tubulin-positive and CGRP-positive epithelial and subbasal nerve bundle areas were significantly higher in the DHA plus NGF group than in the control and NGF or DHA alone. No differences were noted in the SP-positive nerve bundles between the different treatments and the control treatment. CONCLUSIONS: NGF plus DHA treatment after PRK in rabbits is associated with increased corneal nerve surface area, increased epithelial proliferation, and decreased rose bengal staining compared with NGF, DHA, or vehicle control alone. The combination of NGF plus DHA yields faster nerve recovery after PRK and may have therapeutic usefulness in the treatment of post-PRK dry eye and other neurotrophic keratopathies.

Administration, Topical↗
PubMed2004

Prevention of experimental diffuse lamellar keratitis using a novel platelet-activating factor receptor antagonist.

PURPOSE: To determine whether a novel platelet-activating factor (PAF) antagonist prevents experimentally induced diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK). SETTINGS: Department of Ophthalmology and Neuroscience Center of Excellence, Louisiana State University Health Science Center, New Orleans, Louisiana, USA. METHODS: Twenty eyes of 10 New Zealand albino rabbits were used. The left eyes were treated with a peribulbar injection of 0.5 mL of PAF receptor antagonist LAU 0901 (2,4,6-trimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid ester) dissolved in 20 hydroxypropyl B cyclodextrin (30 microg /mL). Two rabbits were treated with a peribulbar injection of 0.5 mL of vehicle (cyclodextrin) alone and served as controls. A corneal flap was cut in all eyes, and the interface was exposed to Pseudomonas aeruginosa endotoxin. The left eyes were additionally treated with 1 drop of LAU 0901 4 times a day. Rabbits were killed on postoperative days 1, 2, 3, 5, and 8. The eyes were enucleated and processed for histopathology and immunohistochemical examination. RESULTS: Corneas not treated with LAU 0901 and controls showed a severe inflammatory response in the flap margin and stromal interface, characterized by loss of keratocytes, activation of adjacent keratocytes and transformation to myofibroblasts, infiltration of polymorphonuclear leukocytes and monocytes, and presence of epithelial cells with necrosis and melting of adjacent stroma. Corneas of rabbits treated with LAU 0901 showed minimal loss of keratocytes and myofibroblast transformation, minimal inflammatory cell infiltration, and minimal presence of epithelial cells in the interface. CONCLUSION: Induction of DLK was blocked by a PAF receptor antagonist in rabbit eyes. The histopathological evaluation and immunohistochemical studies showed that treatment with LAU 0901 blocked keratocyte apoptosis, transformation of fibroblasts to myofibroblasts and migration to the wound site, and chemotaxis of inflammatory cells, inhibiting the inflammatory response and promoting adequate healing of the flap interface and adjacent stroma.

Actins↗
PubMedDate not supplied

Surgical correction of hyperopia.

Surgical attempts to correct hyperopia have yielded varying results over the last 130 years. These techniques include the reshaping of the cornea through incisions, burns, or lamellar cuts with removal of peripheral tissue; the addition of central inlays; laser ablations; and the replacement of the crystalline lens. By examining the success of each surgical technique, the refractive surgeon may be able to make an informed decision on its indications and limitations, based on the specific patient's characteristics. Reporting the outcomes and complications of hyperopic surgery will help refine our approach to the management of an increasingly hyperopic and presbyopic population.

Corneal Surgery, Laser↗
PubMedDate not supplied

Corneal keloid in Lowe syndrome.

We describe a 3-year-old boy with Lowe syndrome who previously underwent bilateral cataract surgery with intraocular lens implantation and strabismus surgery and developed an inferior corneal keloid. The lesion was resected. We report the results of immunohistochemistry analysis of the specimen, as well as alternative treatment modalities for this rare condition.

Cataract↗
PubMedDate not supplied

Five-year follow-up of laser in situ keratomileusis for hyperopia using the Technolas Keracor 117C excimer laser.

PURPOSE: To evaluate safety, predictability, efficiency, and long-term stability of laser in situ keratomileusis (LASIK) for spherical hyperopia. METHODS: This study was a retrospective 5-year analysis of 67 patients (125 eyes) who had LASIK for spherical hyperopia; preoperative mean manifest spherical equivalent refraction was +3.84+/-1.13 D (range +1.00 to +6.50 D) and mean astigmatism was 0.37+/-0.27 D (range 0 to 1.00 D). Preoperative spherical equivalent refraction for the low hyperopia group was +1.00 to +2.75 D; medium hyperopia group, +3.00 to +4.25 D, and high hyperopia group, +4.50 to +6.50 D. All surgeries were performed using the scanning Chiron Technolas Keracor 117C excimer laser. Uncorrected and best spectacle-corrected visual acuity, predictability, long-term stability of refraction, and complications were analyzed. RESULTS: At 5 years after hyperopic LASIK, mean spherical equivalent refraction for the low hyperopia group was +0.48D+/-0.79 D; medium hyperopia group, +1.52+/-1.45 D; high hyperopia group C, +3.39+/-1.98 D. The percentage of eyes with a spherical equivalent refraction within +/-0.50 D of emmetropia for the low hyperopia group was 63% (37 eyes); medium hyperopia group, 42% (20 eyes); high hyperopia group, 22% (4 eyes). Eyes with chronic dry eye symptoms had a mean difference in spherical equivalent refraction from target refraction of +1.43 D compared with +0.84 D for eyes without dry eye symptoms. Five eyes (4%) lost 2 lines of BSCVA at 5 years. CONCLUSION: LASIK was safe, effective, and stable for primary hyperopia between +1.00 and +3.00 D. Higher amounts of hyperopia had poor long-term stability, especially eyes with more than +4.25 D. Chronic dry eye symptoms were associated with regression over time.

Adult↗
PubMedDate not supplied

Long-term refractive results of myopic LASIK complicated with intraoperative epithelial defects.

PURPOSE: To evaluate the long-term refractive results of LASIK for myopia complicated with intraoperative epithelial defects. METHODS: Twenty-six eyes with epithelial defects on the LASIK flap were compared with the contralateral eye that had no intraoperative complications. Pre- and postoperative data were compared between the two groups including 3-, 6- and 12-month postoperative spherical equivalent refraction, amount of undercorrection, and complications. RESULTS: Eyes with intraoperative epithelial defects showed more undercorrection at 3 and 6 months postoperatively (P < .05). No statistically significant difference was noted at 12 months. Twenty (76%) eyes in the epithelial defect group lost best spectacle-corrected visual acuity (BSCVA) at 3 months postoperatively compared with 2 (7%) eyes in the control group. By 1 year, however, only 2 (7%) eyes in the epithelial defect group and no eyes in the control group lost > 1 line of BSCVA. Diffuse lamellar keratitis was observed in 15 (58%) of 26 eyes with epithelial defects and these eyes had more undercorrections at 6 and 12 months (P < .05) and higher corneal irregularity index at 6 and 12 months compared with controls (P < .05). Eyes with small epithelial defects (> 1 mm2 to < 3 mm2) had more undercorrections at 6 months (-1.08 +/- 0.76 diopters [D]) compared with the control group (-0.46 +/- 0.87 D). Eyes with centrally located epithelial defects had more undercorrections and increased corneal irregularity index compared with controls (P < .05). CONCLUSIONS: Intraoperative epithelial defects after LASIK should be considered a severe complication that may result in diffuse lamellar keratitis, induce loss of BSCVA, prolong recovery of visual acuity, and induce undercorrection.

Adult↗
PubMedDate not supplied

A new surgical technique for anterior segment ectasia: tectonic lamellar sclerokeratoplasty.

A 41-year-old patient with severe anterior segment ectasia and a previous history of failed corneal graft was treated by placing a 14-mm tectonic corneoscleral allograft in the eye to support both the corneal and the scleral thinning. Nylon 10-0 interrupted sutures were used at the sclero-scleral junction. The host conjunctiva, including the limbal area, was carefully sutured to the donor limbal area. Three months postoperatively, the graft was stable with no progression of the ectasia. The suturing of a corneoscleral graft over a severely ectatic cornea may be an acceptable technique for providing tectonic tissue support and stabilizing eyes with severe anterior segment ectasia.

Adult↗
PubMedDate not supplied

Bilateral cataract surgery combined with implantation of a brown diaphragm intraocular lens after trabeculectomy for congenital aniridia.

A 17-year-old male patient was referred for poorly controlled glaucoma on maximal medication, congenital aniridia, cataract, nystagmus, and hypoplasia of the macula. A bilateral filtering procedure was performed to control the glaucoma. Three months later, a slow motion phacoemulsification and implantation of a brown diaphragm intraocular lens (IOL) was attempted. Despite the presence of nystagmus and hypoplasia of the macula, the visual acuity improved from 20/300 to 20/100 in the right eye and from 20/400 to 20/150 in the left eye. Both aniridia IOLs were well centered, the anterior segment was quiet with normal intraocular pressure without medication, and all of the patient's glare symptoms disappeared. A single-piece iris diaphragm and optical lens offer a safe alternative for patients who previously had no viable options for iris reconstruction. The most serious postoperative problem, glaucoma, should be addressed before the cataract and lens implantation is performed to avoid a possible acceleration of the glaucoma progression by the large aniridia IOL.

Adolescent↗
PubMedDate not supplied

Management of a displaced angle-supported anterior chamber intraocular lens.

A 49-year-old patient had a displacement of an anterior chamber intraocular lens (IOL) producing a cyclodialysis cleft and persistent hypotony with maculopathy. The patient underwent intraocular lens extraction, repair of the cyclodialysis cleft, and iris-fixation of an acrylic posterior chamber IOL with resolution of the hypotony and improvement of the maculopathy and best-corrected visual acuity. Many surgeons consider the implantation of an anterior chamber IOL as their first choice in the treatment of inadequate capsule support associated with cataract surgery, probably because it is a relatively easy procedure to perform. However, insufficient preoperative knowledge of the anterior segment biometry can lead to inadequate lens size and postoperative complications.

Anterior Chamber↗