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H D Cavanagh

Publications and source records attributed to H D Cavanagh.

At least 19 recordsLinked to original sources
PubMed1995

Assessment of f-actin organization and apical-basal polarity during in vivo cat endothelial wound healing.

PURPOSE: To assess the relationships between cytoskeletal changes and apical-basal polarity during healing of mechanical scrape injuries in the cat corneal endothelium. METHODS: Ten cats (20 eyes) were used in this study. One mechanical scrape injury was created in the corneal endothelium of each eye using a blunt olive tip cannula. Tandem scanning confocal microscopy (TSCM) was performed at sequential time points after injury for in vivo assessment of cell morphology and wound healing rates. In two eyes, scanning electron microscopy was performed to allow verification of TSCM observations. Ten eyes were collected between 6 and 48 hours after wounding for in situ labeling of f-actin, ZO-1, or both. RESULTS: Cat endothelial cell morphology observed using in vivo microscopy was identical to that shown using scanning electron microscopy. During healing, endothelial cells always remained attached to the endothelial sheet, although some showed extensions of lamellipodia into the open wound area. The in situ localization of f-actin also correlated with the TSCM in vivo wound morphology. Quantitative analysis showed that there was a decrease in the intensity of phalloidin-fluorescein isothiocyanate staining at the leading edge of the wound, suggesting a decrease in f-actin; a significant correlation was found between the relative intensity of f-actin staining and the distance from the wound margin (R = 0.98, P < 0.01). At 24 and 48 hours after injury, both ZO-1 and f-actin maintained an apical localization within cells immediately adjacent to the leading edge, despite the considerable distance of movement and dramatic decrease in the intensity of f-actin staining. CONCLUSIONS: Overall, these data demonstrate that after scrape injury in the cat, endothelial cells exhibit a pattern of healing in which total intracellular f-actin is reduced, but normal cell connectivity and apical-basal polarity are maintained throughout.

Actins↗
PubMed1995

Identification and subcellular distribution of muscarinic acetylcholine receptor-related proteins in rabbit corneal and Chinese hamster ovary cells.

PURPOSE: The authors examined the muscarinic acetylcholine receptor (mAChR) subtypes in rabbit corneal epithelial and endothelial cells and in subcellular fractions of these cell types. A Chinese hamster ovary (CHO) cell line (nontransfected CHO K1), expected to be a negative control, also was investigated. METHODS: Whole cell homogenate and subcellular fractions were labeled with the covalent-binding, mAChR-specific ligand [3H]propylbenzilylcholine mustard ([3H]PrBChM) and were analyzed by a combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, or SDS-PAGE, and autoradiography. RESULTS: A pattern of multiple PrBChM-binding proteins was detected in homogenates of corneal epithelial and endothelial cells and, surprisingly, in the CHO cells. Ligand binding to all of these proteins is inhibited by the mAChR antagonists atropine sulfate and quinculidinyl benzilate. The sizes of four of the labeled protein bands are the same as the molecular masses deduced from mAChR sequence data for subtypes m3, m4, m5, and either m1 or m2. One band of 47 kd, smaller than any reported sequence, was also observed. Two of the [3H]PrBChM-binding proteins, one at 59 to 62 kd (corresponding to m5 in size) and another at 47 kd, clearly were present when highly purified nuclei were analyzed. CONCLUSIONS: The presence of multiple mAChR-like proteins at low concentrations in these disparate cell types suggests the possibility of a more general regulatory role for this type of receptor than was considered previously. Combined with other reports, the identification of proteins with the characteristics of mAChRs in purified nuclei adds support to data indicating the likelihood of G-protein-coupled signaling across the nuclear envelope.

Animals↗
PubMed1995

Temporal, 3-dimensional, cellular anatomy of corneal wound tissue.

We have evaluated temporally the 3-dimensional cellular anatomy of corneal wound tissue in the rabbit eye using in vivo tandem scanning confocal microscopy. In vivo microscopic studies showed that corneal fibroblast migrated into the wound as an interconnected cellular meshwork with long, thin, randomly oriented cell processes. Interconnection of fibroblasts was further confirmed by localisation of monoclonal antibodies to connexin 43 which demonstrated prominent staining of putative gap junctions between fibroblasts. Temporal observations indicated that the interconnected cells and cellular processes undergo sequential positional changes leading to orientation of cells and interconnected cell processes parallel to the wound margin. Laser scanning confocal microscopy of en bloc, phalloidin-stained corneal wounds showed prominent intracellular f-actin bundles (i.e. stress fibres) within cell processes which formed an extensive interwoven pattern within the wound.

Actins↗
PubMed1995

Expression of alpha-smooth muscle (alpha-SM) actin during corneal stromal wound healing.

PURPOSE: The purpose of this study was to correlate the temporal expression of alpha-smooth muscle specific actin (alpha-SM actin), a molecular marker for myofibroblast transformation, with corneal wound contraction. METHODS: After full-thickness, central corneal injury in rabbit eyes, the anterior width of the wound (wound gape) was measured in the same animals using in vivo confocal microscopy. In addition, animals were sacrificed at various times after injury for the determination of alpha-SM actin expression by immunofluorescent microscopy using a mouse monoclonal antibody specific for human alpha-actin. Antibody specificity was confirmed by Western blot analysis of normal and wound fibroblasts. Expression of alpha-SM actin also was related spatially to f-actin and the wound margin by co-localization with phalloidin and DTAF (5([4,6-dichlorotriazin-2yl]amino)fluorescein), a fluorescent marker bound to the wound margin. RESULTS: Wound contraction was most evident from days 7 to 42, when wound gape progressively decreased from 574 +/- 120 microns to 250 +/- 61 microns. Thereafter, the wound remained stable to day 84 (304 +/- 58 microns). Expression of alpha-SM actin directly correlated with wound contraction--appearing across the wound at day 7, the full thickness of the wound at day 14, and the posterior wound at day 28. alpha-SM actin was localized exclusively to phalloidin-stained, f-actin microfilament bundles or stress fibers within wound healing fibroblasts, and the disappearance of alpha-SM actin correlated with the concomitant disappearance of stress fibers at days 28 to 42. Staining of the wound margin with DTAF confirmed that the expression of alpha-SM actin was limited to fibroblasts within the wound. CONCLUSIONS: The expression of alpha-SM actin was directly correlated to corneal wound contraction, appearing at the initiation of and disappearing at the completion of the contraction process. Furthermore, the exclusive expression of alpha-SM actin by fibroblasts present only within the wound suggests that local environmental factors unique to the wound may play an important role in myofibroblast transformation.

Actins↗
PubMed1995

Quantitative assessment of anteroposterior keratocyte density in the normal rabbit cornea.

The anteroposterior keratocyte density distribution in the rabbit cornea was measured. Unsectioned tissue blocks from the central cornea of five rabbits were stained with propidium iodide and imaged using a Leica laser scanning confocal microscope. A z-series of images was acquired confocal microscope. A z-series of images was acquired in each sample, from anterior to posterior stroma in either 3- or 8-microns steps. Software was developed to allow interactive marking of the keratocyte nuclei within each section of the z-series and for calculating cell density. For convenience, cell density was expressed as the number of cells per corneal volume element (CVE), where CVE is a newly defined volume unit with x, y, and z dimensions of 250, 250, and 10 microns, respectively. The calculated keratocyte density was 20.2 +/- 1.0 cells/CVE (n = 5), which is equivalent to 32,360 +/- 1,660 cells/mm3. The greatest density was underneath the epithelium (26.3 +/- 2.5 cells/CVE), the density then decreased linearly with depth to 15.2 +/- 1.4 cells/CVE; there was a slight increase in density pre-Descemets membrane to 18.5 +/- 3.5 cells/CVE. A 30% decrease in cell density over the entire anteroposterior stromal thickness was observed. To facilitate statistical analysis, the cell density was averaged over 5% thickness intervals from anterior to posterior cornea. A significant difference in mean cell density of these intervals was found (ANOVA, n = 20, p < 0.01). To further assess the density distribution, linear regression analysis was performed. A significant correlation was found between keratocyte density and stromal depth (R = -0.94, n = 20, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The spatial organization of corneal endothelial cytoskeletal proteins and their relationship to the apical junctional complex.

PURPOSE: To determine the spatial organization of the major cytoskeletal proteins and their relationship to the apical junctional complex (AJC) in the normal rabbit corneal endothelium. METHODS: Normal endothelial cytoskeletal structure in three dimensions was studied in rabbit eyes by laser scanning confocal microscopy after en bloc immunocytochemical staining of whole corneal tissue with various antibodies and fluorescent probes; specificity of antibodies to rabbit corneal endothelial cell proteins was established by Western blot analysis. RESULTS: Normal actin microfilament network organization was seen predominantly as a complex apical array forming a circumferential bundle. The tight junction-associated protein ZO-1 was positive at the apical junctions, forming a hexagonal pattern that was localized between and just proximal to the circumferential actin microfilament bundles. The distribution of ZO-1 was discontinuous around the cell, with the largest gaps (1 micron in diameter) occurring at the Y-junction between adjacent endothelial cells; transmission electron microscopy of the apical face of the endothelium confirmed the existence of 1-micron diameter gaps in the adherens junctions located at the Y-junction. Antivimentin antibodies showed a ring of intermediate filaments located just below the circumferential actin microfilament band. This ring appeared to be continuous with a basal mat of filaments, which together formed a basketlike structure within endothelial cells. An intricate cytoplasmic, perinuclear network of microtubules was observed by antitubulin antibodies that appeared unrelated either to the apical circumferential actin microfilament bundle or to intermediate vimentin filament ring. Staining of endothelial cells with NBD-ceramide identified a prominent, perinuclear Golgi complex suggesting an association between microtubules and Golgi. CONCLUSIONS: The organization of cytoskeletal elements and the tight junction-associated protein ZO-1 is similar to the classical AJC of transporting epithelia, comprised of a zonulae occludens (ZO) located apical to a zonulae adherens (ZA) and desmosomes. The organizational pattern seen in corneal endothelial cells, however, is distinct from transporting epithelia in that the ZO and ZA are discontinuous, with large gaps in the ZO-1 distribution at the Y-junction between adjacent endothelial cells. The authors propose that the structural differences in the AJC underlie the functional differences between classical transporting epithelia, which actively pump fluid from the lumen to the mucosa, and the corneal endothelium, which has a "pump-leak" fluid transport mechanism.

Animals↗
PubMed1992

In vivo confocal microscopy in clinical dental research: an initial appraisal.

Until recently, the in vivo microscopic investigation of intraoral tissues at high resolution has been virtually impossible. Confocal microscopy enables high-resolution imaging to be achieved below semitransparent surfaces in intact living specimens, but this may still be impractical for intraoral applications because of the need to stabilize the sample. The development of a steadying objective (x 240 overall mag.) which is held against the sample surface and is focused by moving internal elements, avoids the need for fine adjustment of the living sample under the microscope to achieve a change of focus. It is therefore more comfortable and also reduces the problems of movement due to the pulse. The objective was used with a tandem scanning microscope, with images recorded via a SIT video camera. Using this system internal tooth structure (e.g. enamel prisms/adhesive restoration interfaces) and the lining cells of the gingival crevice through to the junctional epithelium may be examined. It is also possible to image the oral mucous membrane, focusing to the capillary loops in the basal layers, where streaming red blood cells can be seen. Access is limited to the anterior regions as far back as the premolar teeth. Applications could include caries research, soft and hard tissue responses to biomaterials (e.g. implants), wound healing and monitoring the effect of periodontal treatment regimens. This new technique offers numerous exciting opportunities for the microscopic investigation of many clinical operative procedures in vivo, allowing the response of the tissues to be non-destructively monitored, over time, at high resolution.

Composite Resins↗
PubMed1992

Effect of contact-lens-induced hypoxia on lactate dehydrogenase activity and isozyme in rabbit cornea.

Lactate dehydrogenase (LDH) levels and subunit isozyme patterns in cornea were monitored in 36 albino rabbits wearing thick, rigid, gas-permeable contact lenses for periods of 24 h, 2 and 7 days, and 1 and 3 months. The oxygen transmissibility of the contact lens was 15.3 x 10(-9) (cm/s) (ml O2/ml mm Hg). The activity of LDH in corneal tissue decreased according to the duration of lens wear. The LDH isozyme patterns shifted with lens wear from LDH1,2,3 (heart type, aerobic) to LDH4,5 (skeletal muscle type, anaerobic). The cornea swelled 8.8% with overnight contact lens wear, with increased swelling (11-12%) after further continuous lens wear. After contact lens removal, however, the LDH activity and the isozyme pattern returned to normal, and the corneal thickness quickly returned to normal. Based on these observations, it is suggested that LDH in rabbit corneas was physiologically affected by lens-induced hypoxia, but these changes were reversible. These results might further suggest that tear LDH levels in the human contact lens wearer could provide an ongoing assessment of the tolerance of the lens by the ocular surface.

Animals↗
PubMed1992

Effects of increasing Dk with rigid contact lens extended wear on rabbit corneal epithelium using confocal microscopy.

The effects of 24-h wear of various Dk-rigid gas-permeable (RGP) contact lenses on the rabbit corneal epithelium were studied by in vivo tandem scanning confocal microscopy (TSCM), and confirmed by scanning electron microscopy (SEM). Lenses used were polymethylmethacrylate (PMMA) (Dk/L = 0), RGP experimental A lens (siloxanylmethacrylate-fluoromethacrylate-methylmethacrylate , 33), experimental B (siloxanylmethacrylate-fluoromethacrylate, 56), and experimental C (siloxanylstyrene-fluoromethacrylate copolymer, 64 x 10(-9)) (cm/s) (ml O2/ml mm Hg) with 0.15-mm thickness (Dk/L measured by polarograph including boundary layer effect). After 24-h PMMA lens wear, TSCM showed no superficial epithelial cells but only exposed, underlying wing cells. The cornea with experimental A showed partial superficial epithelial desquamation. With experimental B wear, slight superficial epithelial cell swelling and desquamation were observed on the surface of the cornea. No changes were observed for the eye with experimental C and control. The observed severity of desquamation of superficial epithelial cells was dependent on the oxygen transmissibility (Dk/L) of RGP lenses worn. All in vivo findings were confirmed by SEM observations. Based on the results of this study, we conclude that (a) although Dk/L = 56 lens B shows no residual overnight corneal swelling, surface damage is still produced; (b) Dk/L = 64 lens C is best for epithelium showing the same corneal images as control; and (c) TSCM is a good way to evaluate the contact lens safety and efficacy in vivo at the cellular level noninvasively.

Animals↗
PubMed1992

Digital image acquisition in in vivo confocal microscopy.

A flexible system for the real-time acquisition of in vivo images has been developed. Images are generated using a tandem scanning confocal microscope interfaced to a low-light-level camera. The video signal from the camera is digitized and stored using a Gould image processing system with a real-time digital disk (RTDD). The RTDD can store up to 3200 512 x 512 pixel images at video rates (30 images s-1). Images can be input directly from the camera during the study, or off-line from a Super VHS video recorder. Once a segment of experimental interest is digitized onto the RTDD, the user can interactively step through the images, average stable sequences, and identify candidates for further processing and analysis. Examples of how this system can be used to study the physiology of various organ systems in vivo are presented.

Animals↗
PubMed1992

Comparison of in vivo and ex vivo cellular structure in rabbit eyes detected by tandem scanning microscopy.

Using the tandem scanning microscope, in vivo confocal microscopic images of living eyes were compared to images obtained from ex vivo, freshly enucleated or fixed tissue in the rabbit. In the normal cornea, microscopic details of the superficial epithelium, basal lamina, stromal fibrocyte nuclei, nerves and endothelial cell borders were easily discernible. Removal of the eye from the intact animal resulted in loss of detail with distortion of the normal structural interrelationships within the corneal stroma whilst enhancing details of the corneal epithelium. Formalin fixation further enhanced details of the basal and suprabasal corneal epithelial cell nuclei and the stromal fibrocyte cell borders whilst inducing prominent brightly reflecting folds in the thickened stroma with concomitant enhancement of the edge contrast of the collagen lamellae. These changes appeared to be related, in part, to hydration of the cornea and artefactual pooling of water between structures that may enhance reflectivity by increasing the difference between the refractive index of the cellular and extracellular elements. We conclude that microscopic examination of ex vivo preparations of corneal tissue, although providing increased resolution similar to conventional light microscopic techniques, significantly altered the normal structural relationships and could lead to erroneous measurements of the physiological properties of the tissue as compared to in vivo microscopy of undisturbed, intact tissue.

Animals↗
PubMed1992

A quantitative method for LDH, MDH and albumin levels in tears with ocular surface toxicity scored by Draize criteria in rabbit eyes.

We have established a quantitative method for evaluation of ocular surface lesions on the basis of lactate dehydrogenase (LDH) activity, malate dehydrogenase (MDH) activity, and albumin levels in rabbit tears. Lesions were produced with solutions of 0.005-0.02% benzalkonium chloride (BAK), 0.01-0.03% chlorhexidine digluconate (CHX), and 0.01-0.03% polyhexamethylene biguanide hydrochloride (PHMB), all of which are widely used in topical ophthalmic preparations. Two drops of test solution were instilled 15 times into rabbit eyes at 5 minute intervals. Sixty minutes after 0.02% BAK instillation, tear LDH activity increased from 1,840 U/L (without instillation) to 26,100 U/L, and concomitantly tear albumin levels rose from 0.11 mg/mL (without instillation) to 9.48 mg/mL. Instillation of 0.03% CHX and 0.03% PHMB caused smaller increases in LDH and MDH activity and albumin tear levels. LDH activity and albumin levels in tears were significantly correlated with the degree of total ocular surface lesions in both cornea and conjunctiva as observed by slit lamp biomicroscopy quantified using a modified Draize score. Based on the results of this study, we believe that LDH activity and albumin level in tears can be used as objective indicators for the quantitative evaluation of ocular surface lesions on both cornea and conjunctiva following application of topical ophthalmic preparations containing cytotoxic preservatives in animals and man.

Albumins↗
PubMed1992

Radial keratotomy. 1. The wound healing process and measurement of incisional gape in two animal models using in vivo confocal microscopy.

Using in vivo confocal microscopy, corneal wound healing was evaluated in both rabbit and cat eyes after radial keratotomy. A total of six rabbit and six cat eyes were evaluated sequentially over time for 1 mo after surgery by in vivo confocal microscopy, and quantitative measurements of changes in incisional wound gape were determined. In vivo histopathologic changes were correlated with conventional histopathologic findings in 18 rabbit and 4 cat eyes; the animals were killed at various intervals from 0-30 days after surgery. In the rabbit, in vivo corneal wound healing was characterized by the initial ingrowth of corneal epithelium followed by persistence within the wound without a marked fibrotic response. Measurement of incisional wound gape showed increasing gape from 144 +/- 32 microns on day 0 to 976 +/- 155 microns on day 26 at a distance of 2.4 mm from the optical zone. These in vivo measurements were not significantly different (P = 0.996) from those obtained using conventional histopathologic techniques which showed an incisional wound gape of 252 +/- 112 microns on day 0 and 917 +/- 216 microns on day 26 at 2.5 mm from the optical zone. In the cat eyes, healing of radial keratotomy wounds showed an initial increase in incisional wound gape from 135 +/- 56 microns on day 0 to 245 +/- 88 microns on day 7 at a distance of 2.4 mm from the optical zone. Starting at day 14 and continuing to day 30, there was a progressive decrease in incisional wound gape from 198 +/- 41 microns to 92 +/- 35 microns. Sequential, in vivo histopathologic analyses indicated that increasing incisional wound gape correlated with the retention of corneal epithelium in the wound. Initiation of decreasing incisional wound gape was associated with replacement of the incisional epithelial plug with fibroblastic tissue. These changes in the incisional wound gape observed in the cat suggest that healing of radial keratotomy wounds involves contraction of the wound in response to the ingrowth of fibroblastic cells. Furthermore, the contractile response appears to be biphasic involving a precontractile and contractile phase. Overall these data indicated that in vivo confocal microscopy provides quantitative histopathologic data on living tissue comparable with that obtained with conventional techniques on dead, fixed, and sectioned tissue. Additionally, the absence of wound fibrosis in the rabbit radial keratotomy model raises important questions as to the appropriateness of this experimental model for human radial keratotomy.

Animals↗
PubMed1992

Radial keratotomy. II. Role of the myofibroblast in corneal wound contraction.

The cellular mechanism of corneal wound contraction after radial keratotomy (RK) was studied in a feline eye model. A total of 10 cat eyes were evaluated at various times from 0-30 days after surgery. Changes in the distribution of intracellular filamentous actin, nonmuscle myosin, alpha-actinin, surface membrane alpha 5 beta 1 integrin, and extracellular fibronectin were studied using immunofluorescence and laser confocal and electron microscopy. From day 3-7, staining for fibronectin increased along the wound margin. By day 7, keratocytes adjacent to the wound margin showed increased f-actin staining with intense staining for fibronectin compared with normal keratocytes. Myosin and alpha 5 beta 1 integrin expression was very weak at this time; alpha-actinin was not found. By day 14, fibroblasts within the wound formed f-actin microfilament bundles (stress fibers) which colocalized with fibronectin. Wound-healing fibroblasts also stained positively for alpha 5 beta 1 integrin, myosin, and alpha-actinin (the latter two were colocalized). The presence of myosin and alpha-actinin in the wound fibroblasts and the re-organization of f-actin into stress fibers by day 14 correlated with the development of wound contraction. A comparison of the cellular distribution of actin, myosin, and alpha-actinin with alpha 5 beta 1 integrin 14 days after injury suggested that integrin was localized along stress fiber bundles during wound contraction. The data from this study suggest that modulation of wound gape during healing of RK wounds may involve transformation of the corneal keratocyte to a myofibroblast-like cell and the subsequent formation of intracellular stress fibers composed of f-actin, nonmuscle myosin, and alpha-actinin. Based on the colocalization of fibronectin filaments and f-actin filaments and the unique distribution of alpha 5 beta 1 integrin, these findings support the hypothesis that the tension within the wound is generated by the formation of intracellular stress fibers and the interactions between stress fibers and the extracellular matrix, mediated by specific membrane receptor molecules.

Animals↗
PubMed1992

Radial keratotomy. III. Relationship between wound gape and corneal curvature in primate eyes.

The relationship between changes in wound gape and corneal curvature after radial keratotomy (RK) was evaluated in five primates. Four-incision RK was performed using a diamond knife set to 100% of central corneal thickness with a 3-mm optical zone. In vivo measurements of wound gape were obtained using tandem scanning confocal microscopy at 3, 7, 14, and 45 days after surgery. The changes in corneal contour were measured at the same time points using a corneal modeling system with a specially designed primate cone. Wounds progressively increased in width to a maximum of 38 +/- 1 microns (n = 5) at day 7. After day 7, wounds showed increasing fibrosis which correlated with decreasing wound gape to 20 +/- 1 microns at day 45. A similar temporal change was detected in central corneal curvature (K), with maximum flattening occurring at day 7 (delta K = -3.17 +/- 0.90 diopters, n = 5), and progressive regression of effect to -1.32 +/- 0.61 diopters (n = 5) at day 45. Although there was interanimal variation, the mean temporal changes in corneal curvature significantly paralleled the changes in wound gape (r = -0.96, n = 4, P < 0.05). Based upon these findings, a simple geometric model was proposed which provides a hypothetic foundation for the relationship between corneal curvature and wound gape after RK. Calculations of wound gape made from this analytic model (using the measured topographic data) showed significant correlation with the actual wound gape measurements (r = 0.96, n = 4, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A prospective multicenter clinical trial to assess safety and efficacy of Menicon SF-P RGP lenses for extended wear.

A prospective, multicenter, national clinical trial was undertaken to assess the safety and efficacy of Menicon SF-P (melafocon A) rigid gas permeable (RGP) contact lenses for extended wear in healthy human eyes. Ten investigators enrolled 167 patients (334 eyes), of which 143 (286 eyes) were initially fit with lenses for the 12-month study. Most subjects were reexamined at 18 months or more, with findings essentially unchanged from those noted at 1 year. Two hundred-two eyes (71%) completed the study. Seventy-two eyes (25%) discontinued, and 12 (4%) elected to continue extended wear. During the study, no significant adverse clinical reaction attributable to the lens was observed. Surface irritation, occasional punctate staining, and lens binding were very rare. The average wearing time was 6.2 days, mandated partially by FDA restrictions as well as patient response. As expected, keratometric shifts were principally vertical: less than 0.99 D (69%), 1.00-1.99 D (28%), and 2.00-2.99 D (4%). The majority of changes observed were toward sphericity. Two hundred lens replacements were required, 24% for adjustments in power/base curve. Only 16 lenses were replaced for warpage, and none for discoloration or crazing. Of those completing the study, 76% rated overall lens comfort and satisfaction to be very good. These results suggest that RGP lens extended wear can be safe and effective and offer patients an acceptable alternative to extended wear of disposable hydrogel lenses.

Adolescent↗
PubMed1992

Ciliated respiratory-like epithelium forming cystic conjunctival lesions in a patient with Stevens-Johnson syndrome.

A woman with severe cicatricial conjunctival changes secondary to allopurinol-induced Stevens-Johnson syndrome developed bilateral palpebral conjunctival cysts. Pathologic examination of these lesions revealed respiratory-like pseudostratified ciliated epithelium in the walls of several cysts of one eye. To our knowledge, this is the first report of this phenomenon.

Aged↗