摘要:

AbstractA technique is described for high magnification in vivo photography of epithelial lesions in the human cornea. Combining use of a high resolution, long working‐distance microscope type lens with two‐step photographic enlargement techniques results in photomacrographs with effective linear magnification of up to 500 ×. The method allows studies of size and shape and crude details of epithelial c

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07033.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractIn the period 1979–83 a total of 232 penetrating corneal transplantations were performed with organ culture preserved donor material. Forty‐two operations were made à chaud for central corneal ulcerations. The results of these interventions are reported and discussed. The surgery presented no serious problems and on first post‐operative day the anterior chamber was reformed in all cases, and pain was relieved. Patients were confined to bed only for 1 day. Graft deswelling was slightly retarded compared to planned surgery, but all functioning grafts obtained normal thickness. The overall graft survival rates after 6, 12 and 18 months were 66, 53 and 48%, respectively. For herpetic ulcers the survival after 18 months was 49% and for non‐herpetic ulcers 47%. The grafts failed in all cases where it had been necessary to employ grafts of more than 10 mm. This latter group was comprised of the non‐herpetic cases; were they excluded, the graft survival rate would increase to 60%. Among cases with a clear graft the median visual acuity after 18 months was 0.33 (range<0.1–0.67). Excluding cases with a non‐corneal cause of visual reduction, the median visual acuity was 0.4 (range 0.33–0.67). It is concluded that grafting can be successfully employed in the treatment of central ulcers, as it not only restitutes tissue integrity, but also preserv

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07034.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA case of non‐traumatic recurrent corneal erosion was studied for several days by means of non‐contact photomacrography. The development of cysts and fingerprint‐like lines was registered. A previous suggestion based on histological evidence regarding the origin of some of the cysts, could be conf

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07035.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe short and long‐term healing of the rabbit corneal epithelium was studied after a standardized alkali wound. The wound was inflicted by applying a round filter paper, 5.5 mm in diameter, soaked in 1 N NaOH, for 60 seconds on the central cornea. The wound size and intensity was chosen not to cause melting and perforation, and not to cause vascular ingrowth. n‐Heptanol corneal wounds of the same size were used as control. The eyes were followed for 8 weeks. Two phases of epithelial healing were discerned. The initial healing phase lasted 48 h during which the wound was completely resurfaced. In spite of the more extensive tissue damage caused by alkali, the initial epithelial healing rate was faster than in n‐heptanol wounds. The late healing phase consisted of recurrent epithelial break down, sometimes seen preceded by epithelial blister formation. Four weeks after trauma the state of epithelial healing was at its

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07036.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe centripetal movement of fluorescein and fluorescein‐labelled dextrans (4 to 150 kD) from sclera or cut edge of the cornea was determined in isolated rabbit corneas at 4 and 24 h. Corneas were divided into 5.5 mm diameter central core, inner 5.5 to 8 mm donut, 8 to 12 mm peripheral donut and, where applicable, scleral rim. For all molecules greater than sodium fluorescein (376 D) tracer concentrations in the 5.5 mm core and the 5.5 to 8 mm donut were equal. Without sclera rim, the more central portions of the cornea (5.5 mm core and 5.5 to 8 mm donut) had tracer concentrations equal to those of corneas‐with‐sclera for all tracers greater than 10 kD. The tracer concentrations in the central cornea were the same in the presence or absence of sclera. The data indicate a physiological barrier to the lateral diffusion of molecules greater than 10 kD between the peripheral and more central c

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07037.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractOne eye of 27 patients with keratoconus and 37 normals were examined by photokeratoscopy and topographic pachometry to obtain comparative informations about the corneal shape and thickness profile, characterized by radius of the central curvature K, the coefficient of radius variation RV, the central corneal thickness T and the coefficient of thickness variation TV. RV and TV express the corneal central‐peripheral variation in radius of curvature and thickness, respectively. Compared with normals the keratoconic corneas demonstrate a decrease in K and T and an increase in RV and TV. In the keratoconic eyes the decrease in K is positively correlated to the decrease in T. Further the decrease in K and T are both negatively correlated to the increase in RV and TV. Finally the increase in RV is positively correlated to the increase in TV. The results are in good accordance with an elastic model which implies increased distensibility of the keratoconic corneal tissue as a pathogenetic factor in the development of keratoconu

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07038.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe effect of monocular hydrogel contact lens wear on the osmolality of the tear fluid in the ipsilateral and contralateral eyes was measured. The hydrogel contact lenses were of similar diameter and either 38% or 70% water content with thicknesses of 0.07 mm, 0.15 mm or 0.30 mm. The ipsilateral eye showed an initial 2 m.osm/kg decrease (hypo‐osmotic) in tear fluid osmolality from baseline after lens insertion. After 5 min the osmolality increased (hyperosmotic) to 15 m.osm/kg greater than baseline, remaining around this level for the 60 min of lens wear. This hyperosmotic change was attributed to an increase in water evaporation due to disruption of the tear film by the contact lens. There was a similar pattern of change in the contralateral eye, but of smaller magnitude. All contact lenses produced a similar effect on tear fluid osmolality, except the combination of a 0.30 mm thick lens of 70% water content fitted with a flat bearing relationship which induced a greater hyperosmotic change after 5 min wea

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07039.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA randomized double‐masked experiment was performed to compare the critical oxygen concentrations required to avoid corneal thickening at the central and peripheral cornea. Pachometry was performed on 10 subjects before and after 3 h of corneal exposure to the following gasmixtures: 0.00, 1.01, 2.65, 5.13 and 10.3% oxygen, balance nitrogen. Widely ranging critical values (from 4.4 to 11.6% for the central cornea and 1.7 to 15.8% for the peripheral cornea) could be obtained depending upon the analytical procedure used to treat the data; that is, the choice of reference baseline, the curve fitting procedure adopted and the method of comparing the reference baseline with the fitted curve. The estimates of the critical oxygen requirement of the central cornea are consistent with previous studies when compared using the same analytical procedure. Similar critical values were derived for the central and peripheral cornea for any given analytical procedure (e.g. 9.8% for the central cornea, and 12.3% for the peripheral cornea for zero mean change in corneal thickness). Our findings indicate that anatomical and physiological differences between the central and peripheral cornea do not have clinically significant effects on the minimum oxygen requirements at these respective sites. This result has implications with respect to lens design considerations for alleviating physiological stress of the cornea during contact lens wea

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07040.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA mechanism called emmetropization appears to control the ocular focus over the years. Emmetropization could regulate the refractive media (dimensions of cornea, lens, and axial length), detecting the focus or refractive error of the eye at rest and initiating changes to reduce the refractive error; this concept suggests that a feedback loop is operational. A feedback mechanism for ocular refraction implies that correcting ametropia with lenses initiates a change in the refractive state of the eye. The long‐term effect of corrective lenses on ocular refraction is investigated with a mathematical feedback model that can predict the extent and direction of this change. The results indicate that lenses worsen existing ametropia conditions. However, the use of appropriate lenses in early life can reduce and correct developing ametropi

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07041.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractPolyvinylpyrrolidone‐iodine is a broad spectrum disinfectant which has been used in surgery for several years. The prophylactic effect of PVP‐iodine against panophthalmia was examined in a study including all cataract operated eyes (4111 eyes) from autumn 1981 to the end of 1986. The patients were randomly split up into two groups. Group 1 received PVP‐iodine eye‐drops as a pre‐operative disinfectant, the control group received 2.5% iodine on the skin only. Thirty‐two cases of panophthalmia arose, 0.8% in group 1 (21 out of 2550 eyes) treated with PVP‐iodine, and 0.7 % in the control group (11 out

ISSN:1755-375X    

DOI:10.1111/j.1755-3768.1987.tb07042.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY