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M Assouline

Publications and source records attributed to M Assouline.

34 records · Page 2Linked to original sources
PubMed1995

[Characteristics of corneal topography in candidates for surgery for myopia].

INTRODUCTION: Videokeratography analyses the corneal anterior topography. It is necessary in refractive surgery to estimate the anatomical effect of the surgery and to eliminate early Keratoconus. METHODOLOGY: Corneal anterior topography was studied on 70 consecutive patients (140 eyes) candidates for low myopia surgery (-1 to -6); 87 eyes were wearing regularly contact lenses. With the topographic analysis machine of EYESYS compagny, keratometry (Km) at 3 mm, astigmatism (delta K) at 3 mm, I-S value at 3 mm and 5 mm according to Rabinowitz method were measured in each eye. RESULTS: The average keratometry was 43.50 +/- 1.87 D. The average astigmatism was 0.909 +/- 0.75 D. 51 eyes presented an asymmetric corneal and among them 32 ware contact lenses regularly; 8 eyes out of 140 (6%) presented the association of an high central Keratometry value (> or = 47 D) and corneal asymmetry (I-S > 0.5 value). COMMENTS: The incidence of Keratoconus is higher in a candidate population for refractive surgery by self-selection. Its frequency is difficult to evaluate accurately because of the present limits for the diagnostic measures. In this population, it seems to represent about 6%. CONCLUSION: The videokeratography before refractive surgery is necessary to reveal corneal anterior topography abnormalities and to eliminate early Keratoconus.

Astigmatism↗
PubMed1994

Synthetic scleral reinforcement materials: I. Development and in vivo tissue biocompatibility response.

The surgical treatment of pathological myopia involves the placement of a band cut from donor sclera around the back of the globe to provide support and to prevent elongation that leads to retinal detachment and blindness. In the search for a synthetic material that would overcome the disadvantages of the donor tissue band, we tested 11 types of bands made from 14 polymers in rabbit eyes. Bands were cut from porous and solid materials, as well as porous materials coated with solids and solid materials with porous patches affixed to the posterior surface. Criteria for suitability and biocompatibility included ease of placement and suturing, stable positioning, and absence of long-term tissue response on a cellular level. Testing included evaluation by the surgeons performing the implantations, measurement of the distance between the band and the globe, determination of fibrous capsule thickness and amount of collagen deposition, and enumeration of macrophages accumulated at the band/capsule interface. Based on the results of these studies, two of the porous materials (expanded polytetrafluoroethylene and porous polyurethane fabric) and two of the composite materials (porous polyurethane fabric coated with polyacrylonitrile and silicone with microvilli cut into the posterior surface) were selected for further study.

Animals↗
PubMed1994

[Internal transient palpebral inclusion following dacryocystorhinostomy].

The authors report two cases of postoperative lagophthalmos immediately following ab externo dacrycystorhinostomy (DCR). Two female patients, aged 67 and 62 years, underwent under general analgesia for chronic dacryocystitis with mucocele. An inferior surgical approach, sparing the inner canthal ligament was chosen in both cases. Lagophthalmos was observed on the operated side on the first postoperative day. Normal lid occlusion was present on the contralateral side. Impairement of palpebral occlusion was predominant in the nasal portion of the lid fissure. Upon voluntary and reflex blinking, a reduction in the downward movement of the superior lid was observed. This reduction was not as apparent when the patients were asked to produce a forced blink. Lagophthalmos disappeared progressively over 3 postoperative months in both cases. Neither epiphora nor any corneal complications were observed. Lagophthalmos following DCR via an inferior approach is a previously unreported complication and may be related to the disinsertion of the nasal portion of the orbicularis muscle and periosteum at the time of periosteal cleavage. Recovery of normal lid function may be due to reattachment of the periosteum.

Aged↗
PubMed1993

Effects of scleral reinforcement on the elongation of growing cat eyes.

OBJECTIVE: We investigated the effect of scleral reinforcement on ocular elongation in the rapidly growing eyes of juvenile cats. METHODS: Bands made from donor sclera or expanded polytetrafluoroethylene were used to reinforce one eye of each animal; contralateral eyes underwent sham surgery. RESULTS: During 5 months of follow-up, normal intraocular pressures implied normal functioning of angle structures. A-scan on the central axis showed no difference in globe lengths. Direct physical measurements of the posterior aspect of the globe at enucleation revealed significant decreases in off-center lengthening where reinforcement was present compared with unreinforced areas in the same eyes and in the contralateral unbanded eyes. Venous beading in fundus photographs of three eyes suggested impairment of venous outflow. CONCLUSIONS: Scleral reinforcement appears to control expansion of the growing cat eye to a limited extent, but the effects on vision and retinal perfusion require further investigation.

Animals↗
PubMed1993

[Effect of recombinant human basic fibroblast growth factor (rh-bFGF) on wound healing of the corneal epithelium].

Prior to a possible clinical trial in humans, we studied the wound-healing effect of RH-bFGF in vivo. Healing-rate measurements on 24 deepithelialized rabbit corneas were performed by means of computer-assisted image analysis. A significantly increased healing rate (P = 0.004) was revealed for the 200 ng FGF treated group (rate 1.57 mm2/h) compared to the control group (1.12 mm2/h). To assess the long-term (side) effects of FGF (50 ng topically applied, 2 times daily), 7 rabbits were involved in a model with repeated epithelial scraping of an anterior keratectomy wound (performed with Draeger's rotokeratom to a depth of 0.15 mm). Light and transmission electron micrographs of treated corneas showed an increased fibrogenesis in the anterior stroma with more pronounced activation of keratocytes. No evidence of abnormal neovascularization or inflammation was observed when compared to control corneas. We suggest that topical RH-bFGF promotes corneal wound healing with virtually no detectable adverse reactions. These results seem to be of considerable interest for the possible therapeutic use of rh-bFGF in patients with superficial corneal epithelial lesions.

Animals↗
PubMed1993

[Transient internal palpebral inocclusion after dacryocystorhinostomy].

The authors report two cases of postoperative lagophthalmos immediately following ab externo dacryocystorhinostomy (DCR). Two female patients, aged 67 and 62 years, underwent under general analgesia for chronic dacryocystitis with mucocele. An inferior surgical approach, sparing the inner canthal ligament was chosen in both cases.

Aged↗
PubMed1992

Recombinant human basic fibroblast growth factor (Rh-bFGF) in three different wound models in rabbits: corneal wound healing effect and pharmacology.

Prior to a clinical trial in humans, we studied the effect and pharmacological distribution of recombinant human basic fibroblast growth-factor (Rh-bFGF) in vivo. Healing experiments on de-epithelialized rabbits corneas (n = 24 animals) compared the efficacy of three bFGF doses to controls and revealed a significantly increased healing rate for both 200 ng and 500 ng per application Rh-bFGF treatment groups compared to the control groups. To assess possible side effects of Rh-bFGF (500 ng topically applied for up to 7 days, twice daily), ten rabbits were involved in a model of an anterior keratectomy wound (performed with Draeger's roto-keratome to a depth of 0.15 mm). Light microscopy of thin sections of treated corneas showed an increased fibrogenesis in the anterior stroma with a more pronounced activation of keratocytes. No evidence for abnormal neovascularization or inflammation was observed when compared to control corneas. Ocular penetration and systemic distribution of topically applied labelled 125I FGF was assessed in three models (iodine vapour epithelial burn, anterior keratectomy and penetrating autokeratoplasty) in 24 rabbits. No intraocular penetration of bFGF occurred as shown by direct gamma counting. Macroautoradiography showed a selective labelling of epithelial basement membrane when denuded and intact, as previously described. Evidence for systemic absorption of breakdown products was confirmed by heparin-sepharose chromatography of blood and urine samples. Under these conditions, we suggest that topical Rh-bFGF promotes corneal wound healing without morphological adverse reaction or intraocular and systemic penetration.

Animals↗
PubMed1992

Early diagnosis of infectious keratitis with in vivo real time confocal microscopy.

The tandem scanning confocal microscope (TSM) was adapted for in vivo examination of the cornea in rabbits with experimental bacterial and fungal keratitis. Compared to slit lamp biomicroscopy, the TSM provides superior lateral and axial resolution and serial optical sectioning capability, which may be useful for identification of corneal pathogens in the early stages of infection. We used the TSM to examine normal rabbit eyes infected with bacteria (Bacillus cereus) and a filamentous fungus (Aspergillus). We also examined a human cornea removed by penetrating keratoplasty after a clinical diagnosis of amoebic keratitis. In the early stages of bacterial infection, slit lamp examination revealed a nonspecific minimal stromal haze and limbal injection indistinguishable from sterile ulcers and epithelial defects. With the TSM, bacteria were visible as highly refractile bodies in the epithelium and superficial stroma. Branching fungal hyphae were also easily identified by the TSM, as were Acanthamoeba cysts and parasites in the subepithelial stroma. Our results indicate that this technique may provide a new modality for quickly and accurately identifying the agent of corneal infection, thereby facilitating prompt and appropriate treatment.

Acanthamoeba Keratitis↗
PubMed1992

Effect of growth factors on collagen lattice contraction by human keratocytes.

A three-dimensional gel contraction model was used to evaluate interactions between human keratocytes and different kinds of collagen in the presence or absence of various growth factors. Bovine collagen type I or human placental copolymerized collagen type I/III was used to create the lattices. Normal keratocytes from neonatal, aged, and insulin-dependent diabetic donors, as well as abnormal keratocytes from a donor with macular corneal dystrophy, were cultured. Growth factors included epidermal growth factor (EGF), basic fibroblastic growth factor (FGF), insulin-like growth factor (IGF-I), and platelet-derived growth factor homodimer beta beta (PDGF). Gel area and optical transmittance were determined from computerized measurements. Dose-response experiments (0.01-100 ng/ml) demonstrated that PDGF at 10 ng/ml (P less than 0.005) and EGF at 1 and 10 ng/ml (P less than 0.0001) were the most effective in promoting gel contraction, compared to IGF-I and FGF. Comparison of cell strains revealed different dose-response profiles. Cells from insulin-dependent diabetics and cells from a donor with macular dystrophy contracted lattices more rapidly than cells from normal neonates (P less than 0.0001). Lattices of copolymerized human collagen type III/I demonstrated significantly reduced contraction rates (P less than 0.0001) and increased optical transmittance, compared to bovine collagen type I lattices. Ultrastructural studies revealed that keratocytes extend processes to form a network within the collagen lattice. Specialized intercellular junctional complexes were observed by transmission electron microscopy. This model provides a useful in vitro corneal stroma-equivalent for the study of keratocyte, extracellular matrix, and growth factor interactions.

Adolescent↗
PubMed1989

In vivo binding of topically applied human bFGF on rabbit corneal epithelial wound.

We present the results of the first evaluation of human placenta extracted basic fibroblast growth factor (bFGF) in a rabbit corneal epithelium wound-healing model. Healing dose-response experiments after selective epithelial wounding with iodine vapors demonstrated that bFGF accelerated the repair process in a saturable manner. Corneal binding of topically applied 125I-labeled bFGF was investigated using radioassay and autoradiographic techniques. Basic FGF was shown to bind specifically to denuded epithelial basement membrane in a very stable fashion and not to the intact epithelium. No transfer of the topical bFGF to the aqueous humor or any intraocular structure could be observed. The stability of this interaction was further demonstrated by reextracting and characterizing the labeled factor from treated corneas. The specificity of the fixation was documented by in vivo topical competition with unlabeled bFGF or heparin. We propose that bFGF-basement membrane interactions play a role in corneal wound healing.

Administration, Topical↗
PubMedDate not supplied

Effect of platelet-derived growth factor on rabbit corneal wound healing.

Human recombinant platelet-derived growth factor was evaluated with the use of wound healing models in New Zealand albino rabbits. The efficacy of the platelet-derived growth factor dimers, AA, AB, and BB, was determined in corneal reepithelialization and anterior keratectomy models which examined the healing response in the presence or absence of the basement membrane. All dimers increased the rate of wound healing in both models at 100 microg/ml when compared with control; however, the platelet-derived growth factor-BB isoform showed the most dramatic increase in both studies. The strength of the healing stroma after incision was evaluated by means of a tensile strength model. Histologic evaluation of the stromal wound area after 9 days of healing showed a marked increase in the number of keratocytes within the wound bed of the corneas treated with platelet-derived growth factor-BB when compared with control corneas. In addition, at 9 days, the epithelial plug was still present in the control corneas but had been extruded to the surface by the granulation tissue in the platelet-derived growth factor-BB-treated corneas. These results are indicative of a more advanced stage of healing in treated versus control wounds at 9 days after the operation. A 30% increase in corneal tensile strength versus control was noted after 21 days of healing. Finally, in an in vitro gel contraction assay, platelet-derived growth factor exhibited a dose-dependent effect on the contraction of fibroblasts for doses ranging from 0.01 to 10 ng/ml. These results indicate that platelet-derived growth factor is active in the corneal wound healing process.

Journal Article↗
PubMedDate not supplied

Ultrasound biomicroscopy of Baikoff anterior chamber phakic intraocular lenses.

BACKGROUND: The purpose of the study was to analyze qualitatively and quantitatively anatomic relationships of anterior chamber Baikoff phakic intraocular lenses (IOL) to the cornea, angle, iris, and lens in myopic eyes. METHODS: Thirteen phakic myopic eyes (-9.00 to -15.00 diopters) corrected by minus power, angle-supported, anterior chamber intraocular lenses of the ZB5M style (Chiron-Domilens), with a mean follow-up of 25 months (range 18 to 36 months), were examined clinically and by ultrasound biomicroscopy. RESULTS: The mean distance (+/- SD) between the central cornea and the IOL was 2.05 +/- 0.18 mm (range 1.8 to 2.47 mm); mean distance between the corneal periphery and the IOL was 1.56 +/- 0.17 mm (range 1.33 to 1.95 mm); and the mean distance between the IOL and the lens was 0.58 +/- 0.12 mm (range 0.48 to 0.81 mm). IOL footplates seemed to be correctly positioned in the angle in all eyes. We observed no goniosynechiae. In six eyes, we found localized posterior indentation of the iris caused by the haptics. Four of these six eyes exhibited oval pupils associated with an oversized IOL. CONCLUSIONS: High frequency ultrasound biomicroscopy can define anatomic relationships of anterior chamber phakic IOLs, and help analyze the mechanisms of corneal and iris complications.

Adult↗
PubMedDate not supplied

[Alloplastic keratophakia. Use of a new polymer].

Alloplastic keratophakia has been performed with a new hydrogel, never used in Ophthalmology (poly-anionical material). Physical and chemical properties are evaluated. In vitro and in vivo studies disclosed a very good biocompatibility.

Animals↗