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PubMed2000

Uveal effusion syndrome: clinical features, surgical treatment, histologic examination of the sclera, and pathophysiology.

PURPOSE: To clarify clinical features and pathophysiology and to evaluate surgical outcome of subscleral sclerectomy for primary uveal effusion syndrome. DESIGN: Prospective, consecutive noncomparative case series. PARTICIPANTS: Nineteen eyes of 16 patients diagnosed with uveal effusion syndrome treated in our clinic between 1989 and 1998. METHODS: Patients were examined by routine ophthalmologic examinations, fluorescein and indocyanine green angiography; measurement of the axial length of the eyeball; magnetic resonance imaging; and echography. Subscleral sclerectomy (sclerectomy under the scleral flap) was performed at the equator on all patients. Histologic examination of excised sclera was carried out on all samples. Patients were followed for outcome over time. MAIN OUTCOME MEASURES: Reattachment of the choroid and retina with resolution of the serous fluid. RESULTS: Three subgroups were identified: In type 1, nanophthalmic eye; the eyeball is small (average axial length 16 mm) and high hypermetropic (average +16 diopters); in type 2, the eyeball size is normal (average axial length 21 mm) with small refractive error; and in type 3, the eyeball size is normal. Histologically, types 1 and 2 demonstrated abnormal sclera with disorganization of collagen fiber bundles and deposits of proteoglycans in the matrix, whereas type 3 showed normal sclera. Subscleral sclerectomy was effective for types 1 and 2, inducing postoperative resolution of the subretinal fluid. However, type 3 eyes were not helped by this technique. CONCLUSIONS: Primary uveal effusion syndrome is caused by abnormalities of the sclera and increased resistance to transscleral fluid outflow as subscleral sclerectomy is an effective treatment in types 1 and 2 only, correct preoperative classification is essential for early surgical management.

Adult↗
PubMed2003

In vitro study of bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera.

PURPOSE: To study bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera and the difference in bacterial adherence to these tissues. SETTING: Research Laboratory, Loyola University Medical Center, Maywood, Illinois, USA. METHODS: Specimens of processed dura mater, processed human pericardium, pericardium in saline, and human sclera (N = 32) were exposed to Staphylococcus epidermidis (concentration 3 x 10(8)) for 10, 20, 40, and 60 minutes, washed for 5 seconds, fixed, and processed for scanning electron microscopy (SEM). Each bacterial count represents an average of 50 random SEM fields at x5,000 magnification. After SEM, selected specimens were processed for transmission electron microscopy. RESULTS: The mean number of bacteria/mm(2) +/- SD adhering to the tissues at 10, 20, 40, and 60 minutes, respectively, were dura mater, 107,833 +/- 65,410, 104,500 +/- 13,471, 96,067 +/- 113,884, and 204,267 +/- 153,697; processed pericardium, 131,550 +/- 86,194, 100,900 +/- 20,031, 144,683 +/- 51,730, and 176,933 +/- 111,818; pericardium in saline, 7,925 +/- 1,520, 33,933 +/- 32,085, 1,217 +/- 1,287, and 21,550 +/- 16,436; and human sclera, 4,850 +/- 2,121, 23,700 +/- 17,961, 5,150 +/- 1,273, and 8,175 +/- 8,450. A 2-way analysis of variance showed significant differences among groups (P =.001) and no significant difference in sample time (P =.929). CONCLUSIONS: Bacterial adherence to processed dura mater, processed pericardium, pericardium in saline, and human sclera should be considered when these materials are used clinically during ophthalmic surgery and other surgical specialties. Adequate broad-spectrum antibiotic coverage is needed to prevent infection and subsequent complications in patients.

Bacterial Adhesion↗
PubMed2001

Glycosaminoglycan synthesis in the separate layers of the chick sclera during myopic eye growth: comparison with mammals.

PURPOSE: Studies in animal models of refractive development have shown that the development of and recovery from induced myopia is associated with visually-guided changes in scleral glycosaminoglycan synthesis. The present study sought to determine whether differential patterns of scleral glycosaminoglycan synthesis are present in the fibrous scleral layer of the chick during myopia development or recovery, as has previously been reported in the mammalian sclera. METHODS: Myopia was induced in young chicks by monocular deprivation of pattern vision over 5 days. Other animals underwent monocular deprivation, then had the occluder removed and were allowed 2 days of recovery. A group of age-matched normal animals served as a control. Newly synthesised glycosaminoglycans in the scleral layers were labelled in vivo, using a [(35)S]-labelled precursor delivered intraperitoneally on the final experimental day. Incorporation of this sulphate into glycosaminoglycans of the fibrous and cartilaginous scleral layers was assessed in proteinase K digests by selective precipitation with alcian blue. RESULTS: Glycosaminoglycan synthesis in the fibrous scleral layers of myopic and recovering eyes was not significantly different to contralateral control eyes (+14 +/- 7%, p = 0.09 and -2 +/- 4%, p = 0.64 respectively). In contrast, glycosaminoglycan synthesis was significantly elevated, relative to controls, in the cartilaginous scleral layer of eyes developing myopia (+63 +/- 18%, p < 0.02), whereas in recovering eyes there was found to be a significant decrease in synthesis in the cartilaginous layer (-40 +/- 6%, p < 0.001). CONCLUSIONS: The results of the current study demonstrate that the fibrous scleral layer of the chick does not display the characteristic differential patterns of glycosaminoglycan synthesis that are found in the mammalian sclera during myopia development and recovery. However, as has previously been reported, the cartilaginous layer of the chick sclera does display differential glycosaminoglycan expression, although the direction of regulation is opposite to that found in the fibrous sclera of mammals.

Animals↗
PubMed1985

Optical properties of the sclera.

A relationship between the structure of the sclera and its light scattering properties is proposed. The relative optical density as a function of wavelength in the infrared was measured for three sclera and a good correlation with the predicted function was found. The angular distribution of the scattered light at 632.8 nm as well as the degree of polarisation of the scattered light at zero angle was measured for three sclera; from these results the total transmission of the sclera was determined.

Collagen↗
PubMed2003

How long can donor sclera be safely stored?

PURPOSE: To determine whether after prolonged storage of sclera in glycerin, there is any bacteriologic contamination that will reactivate, whether reconstituted sclera retains its tensile strength, and whether sclera retains its microstructural integrity. METHODS: Sixty-six scleral shells stored in glycerin for 9 to 19 years, as well as 11 controls stored for 6 months to 4 years, were studied by cutting a small wedge of tissue from the anterior margin of each and directly inoculating into thioglycolate broth, cutting an equatorial ring and determining its break strength using a tensiometer, and cutting a small piece from the remaining posterior portion and examining by scanning electron microscopy. RESULTS: After such prolonged storage, bacteriologic contamination was not detected, tensile strength generally increased with increasing duration of storage, and ultrastructural integrity was maintained on scanning electron microscopy. CONCLUSIONS: This study suggests that storage of scleral shells can be safely prolonged; we hope this can facilitate an increased supply of donated sclera to patients and surgeons.

Bacteria↗
PubMed1991

A quantitative analysis of transparency in the human sclera and cornea using Fourier methods.

Cellular microstructure observed by scanning transmission electron microscopy (STEM) was analysed using Fourier methods. Fourier components of the density fluctuations in the sclera and the cornea of the human eye were quantified. The results show that the Fourier components responsible for the opacity of the sclera have sizes of the order of the wavelength of visible light. In the sclera, approximately 54% of the spectral energy of the density fluctuation falls in the range of 200-1100 nm (scattering range). In the cornea, approximately 24% of the total spectral energy falls in this range. The predominant Fourier components of the density fluctuations in the opaque sclera are approximately 300 nm in wavelength, whereas those of the transparent cornea are approximately 80 nm in wavelength. This method will be useful in quantitative analysis of microstructural changes accompanying biological phenomena such as normal development of transparency in the human lens, and abnormal loss of transparency during cataract formation.

Cornea↗
PubMed1987

An increased number of mast cells in the sclerae of alloxan-diabetic mice.

The number of mast cells in the sclerae and retinae has been investigated in alloxan-diabetic mice, in obese-hyperglycaemic mice and in non-diabetic, lean control animals. In contrast to the alloxan-diabetic mice the obese-hyperglycaemic animals have increased circulating inulin levels. In the sclerae of alloxan-diabetic mice the number of mast cells was significantly (P less than 0.05) increased. No increase in mast cell content could be observed in the sclerae of the obese-hyperglycaemic mice. No mast cells could be observed in the retina in any of the experimental groups. It is concluded that lack of insulin may be of importance for the accumulation of mast cells in the sclerae of mice with hyperglycaemia.

Animals↗
PubMed2004

Pressure-induced changes in axial eye length of chick and tree shrew: significance of myofibroblasts in the sclera.

PURPOSE: To investigate the change in axial eye dimensions resulting from stretching the sclera by acute elevation of intraocular pressure (IOP). METHODS: IOP was increased to 100 mm Hg for 1 hour through an intravitreal cannula, while ocular component dimensions were monitored every 10 minutes with A-scan ultrasound in anesthetized animals (10 chicks and 10 tree shrews). In addition, immunocytochemical detection of alpha-smooth muscle actin (alpha-SMA) using a monoclonal antibody was conducted in the sclera of the tree shrew and the chick. RESULTS: In both species, axial eye length immediately and significantly (P < 0.0001) increased on elevation of IOP to 100 mm Hg: chick to 103.9%, tree shrew to 101.2% (mean percentage of original measured at 15 mm Hg). After 1 hour of maintained pressure, chick eyes showed a further significant increase in axial length (to 108.6%), but axial length of tree shrew eyes decreased (to 100.3%) to the point that it was not significantly different from the original value at 15 mm Hg. Immunocytochemical studies of age-matched tissue demonstrated the presence of alpha-SMA-containing fibroblasts (myofibroblasts) within tree shrew but not chick sclera. CONCLUSIONS: Elevation of IOP caused axial elongation of chick eyes, but a consistent reduction in axial length of tree shrew eyes. The presence of myofibroblasts, demonstrated in tree shrew but not chick sclera, suggests that the reduction in axial length of tree shrew eyes may have been caused by activation of a contractile mechanism involving scleral myofibroblasts. Such a mechanism may play a role in the regulation of eye size and refractive development.

Actins↗
PubMed2005

Selective regulation of MMP and TIMP mRNA levels in tree shrew sclera during minus lens compensation and recovery.

PURPOSE: In juvenile tree shrews, a minus-power lens placed in front of the eye produces increased axial elongation and a myopic shift in refractive state that compensates for the power of the lens. Scleral tissue remodeling and modulation of the mechanical properties of the sclera occur during lens compensation. In this study, the time course of changes in scleral mRNA levels of three MMPs and three TIMPs during compensation for a minus lens and during recovery was investigated, to determine which, if any, are temporally associated with changes in the mechanical properties of the sclera and the axial elongation rate. METHODS: Competitive RT-PCR was used to measure the levels of mRNA for MT1-MMP, MMP-2, MMP-3, TIMP-1, TIMP-2, and TIMP-3 in the scleras of tree shrews that had received either 1, 2, 4, or 11 days of monocular -5-D lens treatment, or 11 days of -5-D lens treatment followed by 2 or 4 days of recovery. RESULTS: Relative to their control eyes, treated eye MT1-MMP and MMP-2 mRNA levels were significantly higher, and TIMP-3 levels were lower by 1 to 4 days of minus lens treatment. These differential effects were absent by 11 days of treatment when the treated eyes had compensated for the lens. The levels of all three TIMPs spiked upward in both eyes after 2 days of recovery. The differential changes in MT1-MMP, MMP-2, and TIMP-3 mRNA levels were all restricted to the treated eye and were temporally associated with the differential changes in axial elongation, refractive state, and the previously measured changes in creep rate. CONCLUSIONS: The observed changes in MT1-MMP, MMP-2, TIMP-2, and TIMP-3 mRNA are consistent with visually modulated MT1-MMP activation of MMP-2 and with MT1-MMP degradation of scleral extracellular matrix components. These data constitute further evidence that visual signals modulate gene expression of selected MMPs and TIMPs to control scleral remodeling, the mechanical properties of the sclera, axial elongation, and refractive state.

Animals↗
PubMed2006

Differential gene expression in mouse sclera during ocular development.

PURPOSE: Ocular development involves changes in extracellular matrix components of the scleral wall as it expands. This study was conducted to determine scleral gene expression profiles during mouse ocular development to identify genes involved in normal scleral growth. METHODS: Sample sets of pooled sclerae of 3- and 8-week-old mice were microdissected, and total RNA was isolated. After reverse transcription, the cDNA was in vitro transcribed to produce biotin-labeled cRNA. The purified biotin-labeled cRNA samples were hybridized to microarray chips (GeneChip Mouse Genome 430 2.0; Affymetrix, Santa Clara, CA). Gene transcript expression profiles were determined, and eight differentially expressed genes between the two age groups underwent further confirmation by real-time PCR analysis. RESULTS: Differential regulation of 4884 gene transcripts in mouse sclera with less than 5% false-discovery rate (FDR) was identified. The top 1000 with the lowest FDR among the 4884 probe sets were filtered for threefold changes between the two age groups, and 718 gene transcripts were identified. Among these 718 gene transcripts, 210 were upregulated and 508 downregulated in adult relative to juvenile mouse sclera. TGF-beta1 and several collagen genes were significantly downregulated. Microarray differential expression by real-time PCR validation of eight extracellular matrix-associated gene transcripts was confirmed. CONCLUSIONS: This is the first study to demonstrate gene expression profiles in mouse sclera during ocular growth. These findings support the role of TGFbeta1 as a signaling molecule in modulating extracellular matrix during ocular development. This endeavor may be helpful in furthering understanding of how scleral remodeling is regulated during eye growth.

Animals↗
PubMed1983

Osteogenesis imperfecta with dominant inheritance and normal sclerae.

Most patients with dominantly inherited osteogenesis imperfecta have blue sclerae and relatively mild symptoms. However, in a small group of families the patients have normal sclerae and this disorder has been classified as Type 4 osteogenesis imperfecta. This paper reports the clinical and radiographical features of 48 patients from 16 families with Type 4 osteogenesis imperfecta and compares the findings with those of the classical disorder with blue sclerae (Type 1 osteogenesis imperfecta). The two types are similar in usually causing a mild disease but with a wide range of severity, and in both types the rate of fracture declines in adolescence. There are, however, some significant differences apart from the colour of the sclerae. In Type 4 the first fracture more commonly occurs at birth, dentinogenesis imperfecta is more frequent than in Type 1 and bruising and nose-bleeds are less common. As in Type 1, the radiographic appearances of the bones may be normal. It is important that Type 4 osteogenesis imperfecta should be recognised because of the need for competent genetic counselling, because the management may be different from that appropriate for Type 1 and because it may be mistaken for idiopathic juvenile osteoporosis or child abuse.

Adolescent↗
PubMed1980

Clinical and laboratory studies on human sclera allografts.

In the first section of this two-part report human peripheral blood leukocytes were tested for reactivity to extracts of sclera. Absence of scleral antigenicity is suggested by the results which showed that the leukocytes reacted similarly in sclera stimulated cultures and in the controls. The second part of the report discusses the clinical aspects of sclera allografts and provides guidelines for their clinical use. A case is presented where a sclera graft was in position for approximately a year. The tooth was removed with the attached graft and a histologic study made.

Alveolar Process↗
PubMedDate not supplied

Modified bare sclera method for the treatment of primary pterygium: a preliminary report.

INTRODUCTION: The bare sclera technique is still in use by many surgeons worldwide in spite of the attendant high recurrence rate. Any modification of this well known procedure may be more widely acceptable if associated with lower recurrence. METHOD: The bare sclera technique was modified by performing a partial thickness sclerectomy from the pterygium bed. This modified technique was applied to 23 eyes of 17 patients with primary pterygium. The subjects were followed up for varying periods between 8 to 31months to determine the recurrence rate of pterygium after surgical excision and other complications. RESULTS: Initial observation showed that the recurrence occurred in two eyes of two patients of a series who were followed up for a minimum of six months and up to thirty-one months. Two other eyes developed suture granuloma. There were no other complications observed in the remaining twenty eyes of fifteen patients. CONCLUSION: Partial thickness sclerectomy when performed with standard bare sclera technique seems promising and may improve the results of pterygium excision by bare sclera method.

Adult↗
PubMed1999

[The effects of single mitomycin C application on the expression of matrix metalloproteinase in the sclera and aqueous of albino rabbits].

BACKGROUND: Topically applied mitomycin C, which is used to prevent scar formation after filtering surgery for glaucoma, is known to cause reduction in scleral cells and abnormal remodelling of scleral extracellular matrices. I examined in this study the effects of mitomycin C on the expression of matrix metalloproteinase in the sclera and aqueous humor. METHOD: Mytomycin C was applied for 5 minutes to the bared sclera of 14 albino rabbit eyes. The sclera was organ cultured after 1 week, 2 weeks, and 1 month. The culture medium was subjected to zymography to quantitate the gelatinase activity. In situ zymography was performed on the sclera obtained 1 month after mitomycin C application. The aqueous was also subjected to zymography. FINDINGS: The scleral tissue and its cultured media showed enhanced gelatinase activity. The aqueous showed no changes in gelatinase activity. CONCLUSION: Increased activity in matrix metalloproteinase may be involved in the abnormal remodelling of scleral extracellular matrices after application of mitomycin C.

Administration, Topical↗
PubMed1999

Decontamination of human sclera: an in vitro study.

PURPOSE: The human sclera is frequently used in ophthalmic surgeries and must be preserved in disinfectants that prevent its contamination. In this study the efficiency of glycerin, absolute alcohol (ethanol), and benzalkonium chloride (1:5,000) as human sclera disinfectants were compared. METHODS: Fresh human scleras were trephined, the scleral disks divided into three groups and contaminated with Staphylococcus aureus (ATCC 29213), Pseudomonas aeruginosa (ATCC 27853), or Bacillus cereus (ATCC 11778) for 24 h. Thereafter they were transferred to preservation vials each containing glycerin, absolute alcohol, benzalkonium chloride diluted in 70% alcohol (1:5,000) or Trypticase Soy Broth (control), respectively, and stored at room temperature. From each vial, two scleral disks were removed after 1, 2, 3, 4, 7, 10, and 14 days of immersion. Both were plated on blood agar, one being macerated, and both incubated at 37 degrees C for 48 h. RESULTS: Pseudomonas aeruginosa, S. aureus, and B. cereus were recovered from the glycerin-immersed scleral disks until the second, fourth, and fourteenth days, respectively. Bacillus cereus was recovered from those immersed in absolute alcohol until the fourteenth day, whereas disks infected with the other microorganisms and immersed in absolute alcohol presented no growth since the very first day of immersion. Bacillus cereus was recovered from scleral disks immersed in benzalkonium chloride diluted in 70% alcohol (1:5,000) only on the first day. CONCLUSION: Resistant microorganisms can survive in scleral tissue preserved in glycerin and absolute alcohol. We conclude that benzalkonium chloride diluted in 70% alcohol (1:5,000) in vitro is the best disinfectant for human sclera after 24 h.

Bacillus cereus↗
PubMed1992

Devices for the control of laser transmission across the sclera during transscleral photocoagulation.

Improving the reproducibility of transscleral photocoagulation necessitates controlling the transmission of the laser beam through the sclera. Two factors make such control problematic: the locally increased transparency of the sclera resulting from the contact procedure and the occurrence of time-related relaxation phenomena. Two instruments have been devised to help control these factors. The first is a mechanical compensation unit comprised of magnets and a spring that allows the force exerted on the sclera to be adjusted to between 0.1 and 0.4 N, the pressure being determined by the outer diameter of the contact tip. The second instrument monitors the portion of the aiming beam reflected by the sclera as a means of determining the exact level of power actually transmitted through it. This information theoretically could be fed back to the treatment laser, allowing the level of power being delivered to be adjusted accordingly.

Ciliary Body↗
PubMed2005

[Dynamic changes of MMP-2 activity in the posterior sclera of chicks with form-deprivation myopia].

OBJECTIVE: To investigate the effect of form-deprivation on level of gelatinase in the posterior sclera in chicks. METHODS: Fifty 1-day-old chicks were monocularly deprived to establish the animal model of form-deprivation myopia (FDM). According to the duration of form-deprivation the experimental chicks were divided randomly and equivalently into 5 groups, which were deprived for 3, 7, 14, 21 and 30 days respectively. Meanwhile the other eyes of the deprived chicks were used as self-control groups and chicks of the same days were chosen randomly as the normal control groups for each FDM group. At each form-deprivation point the changes of degree of diopters and axial length of chicks in each group were recorded. The levels of gelatinase in posterior sclera of the experimental eyes were measured by gelatin enzymography. RESULTS: Compared with the normal and self-control groups, the levels of MMP-2 activity in FDM groups were much higher (P <0.01). With the increase of the time of monocular deprivation these changes became more significant and reached the top after 14 days' deprivation with an inter-group statistical difference (P <0.01). The dynamic changes of MMP-2 activity were the same as those of axial length and degree of diopters in each experimental groups. There was positive correlation between the MMP-2 activity and axial length (r = 0.989, P < 0.01). But there was a negative correlation between the MMP-2 activity and refractive degree. CONCLUSION: Increase of MMP-2 activity in the posterior sclera of chicks would be a direct key factor to trigger sclera ECM remodeling process in chick FDM.

Animals↗
PubMed2005

[Experimental study of using acellular dermal dermis instead of donor sclera in orbital implantation].

OBJECTIVE: To evaluate the histocompatibility of homologous acellular dermal matrix as a wrapping material for a hydroxyapatite orbital implant and compare the speed of fibrovascular ingrowth in hydroxyapatite orbital implant wrapped with homologous acellular dermal matrix and homologous sclera respectively. METHODS: Twenty four New Zealand rabbits were divided into two groups randomly. One group is implanted with hydroxyapatite orbital implant wrapped with homologous acellular dermal matrix behind the globe, the other group with homologous sclera. The observation included immunological reaction of the globe postoperation. Biopsies of implanted material were taken on weeks 1, 4, 8 and 12 postoperation for histopathological and electron microscope examination. RESULTS: Histological examination showed the homologous acellular dermal matrix has no immunological and inflammatory reaction after implanted in orbit. But the speed of fibrovascular ingrowth is a little slower than that of homologous sclera. CONCLUSIONS: The homologous acellular dermal matrix has the better histocompatibility as an encapsulating biomaterial, it can be a new material instead of homologous sclera.

Animals↗