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At least 145 records · Page 8Linked to original sources
PubMed1982

The use of sclera in tympanic membrane reconstruction.

Sclera appears to be an appropriate grafting material because of its high density, high tensile strength, and low antigenicity. Preserved donor sclera has been used for myringoplasty in 125 cases over a 4 year period with an overall success rate for complete closure of the perforation of 96%. Several simple techniques for creating flanges to hold the graft in place were used. The size of the perforations ranged from several millimeters to 80% of the eardrum surface. Most of the cases have been done as outpatients, the adults with local anesthesia and the children with general anesthesia. The advantages of the procedure are: A. readily available graft material; B. high tensile strength of sclera maintains scaffolding effect for long periods of time; C. the flange technique holds the graft at the perforation site and prevents graft lateralization or medialization; D. the procedure can be performed as an outpatient health care costs.

Adult↗
PubMed1991

Quantitative study of collagen and elastin of the optic nerve head and sclera in human and experimental monkey glaucoma.

Quantitative studies of collagen density and fibril size distribution as well as elastin density were carried out in the optic nerve head and sclera of human and experimental monkey glaucoma eyes. The collagen fibrils of the normal lamina cribrosa are smaller and more uniform in size than those of the sclera. This feature may be an adaptation to maximize either elasticity or resistance to mechanical stress. In glaucomatous nerve heads, there is a major disruption of the structure of the lamina cribrosa beam structure, including a decrease in collagen density. The peripapillary sclera undergoes similar collagen density changes to those in the nerve head in human glaucoma eyes. Elastin fiber density is unchanged in the glaucomatous nerve heads that we studied.

Aged↗
PubMedDate not supplied

[Reinforcement of the sclera with new types of synthetic materials in progressive myopia].

The possibility of using a new synthetic material mersilene for scleroplastic operations has been evaluated in experiments and clinical trials were carried out in patients with progressive myopia subjected to sclera fortification. Morphological studies showed the formation of a connective tissue capsule round mersilene; new collagen fibers grow through its cellular structures, thus fortifying the strength of the sclera-graft complex. Clinical results indicate that sclera fortification by a mersilene graft arrested the progress of myopia in almost all (98%) patients by the end of the first year postoperation; by the end of the second year, myopic refraction stabilized in 92% patients. Hence, mersilene transplants are recommended for scleroplasty in progressive myopia.

Adolescent↗
PubMed2000

Proteoglycan composition in the human sclera during growth and aging.

PURPOSE: Scleral proteoglycans were characterized from human donor eyes aged 2 months to 94 years to identify age-related changes in the synthesis and/or accumulation of these extracellular matrix components. METHODS: Newly synthesized proteoglycans (previously radiolabeled with 35SO4) and total accumulated scleral proteoglycans were extracted with 4 M guanidine hydrochloride and separated by molecular sieve chromatography on a Sepharose CL-4B column. The elution positions of newly synthesized and total accumulated proteoglycans were determined by assaying each fraction for radioactivity and glycosaminoglycans, respectively. Regression analyses were performed on the three major proteoglycan peaks to identify age-related changes in scleral proteoglycan composition. Scleral proteoglycans were further purified by anion-exchange chromatography and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses. RESULTS: Human scleral proteoglycans were apparent as three major peaks after chromatography on Sepharose CL-4B. The two faster eluting peaks contained alternative forms of the cartilage proteoglycan, aggrecan, whereas the third peak contained the small proteoglycans biglycan and decorin. The relative percentage of newly synthesized and total accumulated aggrecan increased approximately two- to sixfold from infancy to 94 years. In contrast, the relative percentage of newly synthesized and total accumulated biglycan and decorin decreased by approximately 25%. Chromatography and Western blot results indicated that the absolute amounts of all three proteoglycans significantly increased in concentration within the sclera from birth to the fourth decade. Beyond the fourth decade, decorin and biglycan decreased in all scleral regions and were present in lowest concentrations by the ninth decade. In contrast, aggrecan, which was present in highest concentration in the posterior sclera, was not significantly reduced with increasing age. CONCLUSIONS: The age-related changes in scleral proteoglycan composition observed in the present study are likely to contribute to the regional alterations in biomechanical properties of the sclera associated with growth and aging.

Adolescent↗
PubMed2000

[Full-sclera resection in treatment of retinopathy of prematurity stage 4b].

AIM OF THE PAPER: The prognosis for vision in children with ROP stage 4b is extremely poor and our traditional methods of treatment of retinal detachment are usually ineffective because of marked retinal shortening. Therefore, in the paper a new method of surgical treatment of retinal detachment in stage 4b based on 180 degrees full-sclera resection is presented. MATERIAL AND METHODS: 14 patients with ROP stage 4b were treated with the use of 180 degrees full-sclera resection. RESULTS: Retinal reattachment was obtained in 86% of operated patients. Visual acuity of 0.1 was found after the operation in 57% and 0.08-0.02 in 43% of these children. CONCLUSIONS: 180 degrees full-sclera resection can be recommended as an effective method of treatment of ROP stage 4b in selected patients who meet the inclusion criteria.

Humans↗
PubMed2001

The lipid composition of drusen, Bruch's membrane, and sclera by hot stage polarizing light microscopy.

PURPOSE: To detect and identify, in situ, the lipid composition of drusen, diffuse Bruch's membrane deposits, and sclera in aging human eyes using hot-stage polarizing microscopy (HSPM), a method that allows qualitative determination of lipid subtypes within histologic sections based on morphology and melting temperatures of liquid crystals as monitored by birefringence during heating and cooling. METHODS: Full-thickness buttons of the central macula and the periphery of human eyes from 17 patients were fixed in 5% calcium-buffered formalin. Frozen sections were stained with oil red O or Sudan black or were analyzed by HSPM. RESULTS: Birefringent anisotropic droplets ("maltese crosses") with melting characteristics of cholesterol esters were identified within diffuse Bruch's membrane deposits, drusen, and sclera. Deposits that melted from crystal to oil without any maltese cross formation when cooled were present in the sclera and are consistent with triglyceride-rich deposits. Deposits with optical properties consistent with phospholipids were identified in a single aged eye. Eyes from young donors did not show these changes. CONCLUSIONS: HSPM is a valuable technique for evaluating the nature of lipid deposits in aging eyes. Further studies are warranted to determine whether similar changes are also present in eyes with age-related macular degeneration.

Adolescent↗
PubMed2002

Porcine sclera: thickness and surface area.

PURPOSE: To assess the thickness and surface area of porcine sclera. METHODS: One hundred twenty-eight porcine globes were sectioned from the center of the cornea to the region of the optic nerve. Photographs of the sectioned sclera including a millimeter scale were taken. Photographic slides were projected onto blank paper, and the scleral silhouette was traced. Perpendicular thickness measurements were taken at 1-mm intervals from the limbus to the optic nerve. The sclera of 18 porcine eyes were cut into small pieces, and the surface area was calculated with computerized digital tracing software. RESULTS: The scleral thickness near the corneal scleral limbus was 0.83 +/- 0.2, 0.91 +/- 0.17, and 1.12 +/- 0.23 mm in the small-, medium-, and large-sized pigs, respectively. Thickness decreased to minimum of 0.31 +/- 0.07, 0.35 +/- 0.1, and 0.43 +/- 0.16 mm at a distance of 5 mm from the limbus in the small- and medium-sized pigs and 6 mm in the large-sized pigs, respectively. The mean scleral surface area was 7.78 +/- 0.66, 9.66 +/- 0.75, and 11.92 +/- 1.57 cm(2) in the small-, medium-, and large-sized pigs, whereas the corneal surface area was 1.09 +/- 0.07, 1.15 +/- 0.09, and 1.40 +/- 0.19 cm(2), respectively. CONCLUSIONS: Porcine scleral thickness is very similar to human scleral thickness. The porcine model is an excellent model for studying transscleral drug delivery.

Animals↗
PubMedDate not supplied

Subsurface photodisruption in human sclera: wavelength dependence.

BACKGROUND AND OBJECTIVE: Approximately 105 million people worldwide have glaucoma, and approximately 5 million are blind from its complications. Current surgical techniques often fail because of scarring of the conjunctival tissue, Tenon's tissue, or both. Femtosecond lasers can create highly precise incisions beneath the surface of a tissue, as previously demonstrated in the transparent cornea. Because the sclera is a highly scattering subsurface, photodisruption has not been previously possible. MATERIALS AND METHODS: To overcome scattering, a laser operating at 1,700 nm was used to make subsurface cuts in human sclera in vitro via photodisruption. RESULTS: Sub-10-microm width incisions were created beneath the surface without collateral tissue effects, something not possible with shorter wavelengths used to date in corneal applications with the femtosecond laser. CONCLUSION: Completely subsurface photodisruptions can be accomplished in human sclera in vitro. In vivo studies are required to evaluate the potential use of this technology for scleral applications.

Glaucoma↗
PubMedDate not supplied

Successful use of preserved sclera of eyelid reconstruction.

Eyelid surgery involving resection of more than half the eyelid and formation of full-thickness defect requires not only reconstruction of the anterior lamella, but also reconstruction of the posterior lamella, including the tarsal plate and palpebral conjunctiva. However, no reconstruction methods are of complete satisfaction. We describe our successful experience with 5 cases of eyelid reconstruction using preserved sclera and a report of a typical case of them. Based on our 5 case experience and literature, we compared eyelid reconstruction using preserved sclera to reconstruction using nasal septal or auricular cartilage in terms of external appearance and functions of the eyelid. The outcomes for reconstruction using preserved sclera in all 5 of our patients have been favorable. Previous papers as to this method, even though small in number, also reported no functional and esthetic problems. This method is recommended for eyelid reconstruction due to the good results and its simplicity.

Aged↗
PubMed1992

Ultrastructure of the extracellular matrix of bovine dura mater, optic nerve sheath and sclera.

The sclera, the outermost sheath of the optic nerve and the dura mater have been investigated histologically and ultrastructurally. Although these tissues appear very similar under the light microscope, being dense connective tissues mainly composed of collagen bundles and a limited amount of cells and elastic fibres, they exhibit subtle differences on electron microscopy. In the dura and sclera collagen appears in the form of large, nonuniform fibrils, similar to those commonly found in tendons, while in the optic nerve sheath the fibrils appear smaller and uniform, similar to those commonly observed in reticular tissues, vessel walls and skin. Freeze-fracture also reveals these fibrils to have different subfibrillar architectures, straight or helical, which correspond to 2 distinct forms of collagen fibril previously described (Raspanti et al. 1989). The other extracellular matrix components also vary with the particular collagen fibril structure. Despite their common embryological derivation, the dura mater, optic nerve sheath and sclera exhibit diversification of their extracellular matrix consistent with the mechanical loads to which these tissues are subjected. Our observations indicate that the outermost sheath of the optic nerve resembles the epineurium of peripheral nerves rather than the dura to which it is commonly likened.

Animals↗
PubMedDate not supplied

[Clinical and morphological aspects of the state of the sclera in various types of genetically determined corneal changes].

The authors analyze the results of a morphologic examination of 5 trephination scleral disks in various types of corneal curvature changes: with ectasia of the lower half of the cornea (1), with uneven corneal ectasia (1), with true keratoconus (2), and with keratoglobus (1), and come to a conclusion that involvement of the scleral connective tissue presenting as extracellular dysproteinosis is the morphologic substrate of deterioration of the elastic properties of the sclera, clinically observed in patients with various genetic corneal ectasias. Involvement of the sclera in the dystrophic process indicates a general involvement of the total external capsule of the eye in genetically determined corneal ectasias. The least marked changes presenting as fragmentation and fiber degeneration of collagen bundles are seen in uneven corneal ectasia. More profound changes in the sclera and its homogenization were detected in the patients with true keratoconus, ectasia of the lower half of the cornea, and keratoglobus.

Cornea↗
PubMed1989

Iontophoresis of 5-fluorouracil into the conjunctiva and sclera.

It was investigated in the rabbit eye whether the method of iontophoresis could introduce a sufficient amount of 5-fluorouracil (5-FU) to inhibit fibroblast proliferation into the conjunctiva and sclera, thus considerably reducing the total amount of 5-FU which must be given to the eye. Five-FU was introduced with a simple apparatus which was filled with 5% 5-FU solution and connected to the negative pole of a current source. When the apparatus was placed over the cornea, the 5-FU penetration into the cornea showed a correlation with strength of current (0-0.75 mA). When the apparatus was placed over the bulbar conjunctiva, a sufficient amount of 5-FU to inhibit fibroblast proliferation was introduced into the conjunctiva and sclera with a current of 0.5 mA passed for 30 seconds. Immediately after iontophoresis, mean 5-FU concentrations in the conjunctiva and sclera at the iontophoresis site were 480 and 168 micrograms/g, respectively. They decreased to 0.6 and 1.2 micrograms/g by 10 hr, but were still above the reported ID50 levels for the cultured conjunctival fibroblast. On the other hand, the total amount of 5-FU introduced into the eye averaged only 3.7 micrograms and the current used was much lower than that formerly applied to the patient's cornea.

Animals↗
PubMedDate not supplied

Uveal effusion in Hunter's syndrome. Evidence that abnormal sclera is responsible for the uveal effusion syndrome.

A patient with Hunter's Syndrome (systemic mucopolysaccharidosis type II) was evaluated for bilateral uveal effusion syndrome. The right eye showed a circular peripheral choroidal detachment for 360 degrees. The left eye showed a larger circular peripheral choroidal detachment and an exudative retinal detachment. Evaluation of the sclera during combined sclerectomies and sclerostomies of the left eye revealed markedly thickening sclera and a reduced number of vortex veins. The surgery resulted in complete resolution of the choroidal detachment and exudative retinal detachment of the left eye. The presence of uveal effusion in Hunter's Syndrome, in which the sclera has been histologically demonstrated to be abnormally thickened, supports the recently proposed pathophysiology of the uveal effusion syndrome.

Adult↗
PubMed1983

A study of biochemical and biomechanical qualities of normal and myopic eye sclera in humans of different age groups.

This paper presents an account of a series of parallel experiments aimed at determining the relationship of biochemical and biomechanical qualities of the scleral membrane of the human eye. In all, 59 scleras of humans were tested, including 47 normal scleras of people belonging to different age groups and 12 myopic scleras of mature eyes. It is demonstrated that eye formation in ontogenesis is accompanied by thickening of all scleral regions, especially the posterior region, accumulation of collagen and elastin in the posterior pole par excellence, a reduced share of soluble collagen fractions, a lower content of glycosaminoglycanes in the equatorial region and an increase of tensile strength and elasticity module. The authors distinguish a so-called group of risk marked by a reduced content of collagen in the posterior scleral region as well as a delayed decrease of its soluble fractions with age in the posterior and in the equatorial regions and a diminished tensile strength. For this group, the appearance and progress of myopia is rather probable.

Adolescent↗
PubMed1994

Using donor sclera to create a flap in glaucoma filtering procedures.

We report a surgical technique in which donor sclera is used to create a flap in glaucoma filtering procedures. This simple technique is helpful when the sclera is too thin to safely and effectively form an adequate scleral flap. The use of donor sclera allows the procedure to continue as a guarded procedure and prevents early postoperative hypotony.

Aged↗
PubMed1993

Microwave-induced retinal destruction with sparing of sclera and choriocapillaris.

We studied the effect of short-term hyperthermia on sclera, choroid, and retina by delivering microwave radiation (2.45 GHz) for 1 minute to 12 eyes of Dutch belted pigmented rabbits. Four eyes each were treated with 43 degrees C, 45 degrees C, and 47 degrees C and followed for 4 weeks. The 43 degrees C group showed minimal disruption of retinal pigment epithelium and outer retina, with pigment migration; the 45 degrees C and 47 degrees C groups showed complete retinal and RPE damage, pigment migration, and glial proliferation. At the same time, the sclera and choroid in all of the eyes remained essentially unchanged. We conclude that microwave-induced hyperthermia can create retinal scarring without significant damage to sclera and choriocapillaris. The next experimental step will be to refine the microwave delivery system to ensure predictable and reproducible lesions.

Animals↗
PubMedDate not supplied

[Morphological features of senile and secondary amyloidosis of the iris and sclera in patients with glaucoma].

Morphologic analysis of 173 biopsy specimens of the iris and sclera removed during antiglaucoma surgery in 115 patients with open-angle glaucoma revealed in 44.4% cases extracellular depositions of amyloid, which aggravated the course of glaucomatous process and were pathogenetically significant. Amyloidosis was revealed in the sclera in 82% cases and in the iris in 70%. Amyloid was detected by Congo red staining with control in polarized light and by toluidine blue staining for chondroitin and dermatan sulfates. Vascular and muscular (involving the pupil muscles) forms of amyloidosis were detected in the iris, pericollagen and focal forms in the draining system and sclera. The authors discuss the contribution of amyloidosis to the pathogenesis of glaucoma. These findings confirm M.M. Krasnov's concept about glaucoma polymorphism.

Adult↗
PubMed1988

Sutureless scleral buckle for retinal detachment with thin sclera.

Retinal detachment surgery can be hazardous in the presence of thin sclera, with increased risk of inadvertent perforation. We designed polymethylmethacrylate belt loops that can be fixed to the sclera with cyanoacrylate tissue adhesive, allowing 360 degrees scleral buckling to be performed without sutures. We report the successful use of this technique in a three-year-old girl with a rhegmatogenous retinal detachment and blue sclerae.

Child, Preschool↗