Aim: The primary aim of this study was to find if there is any correlation between the corneal radius of curvature and its eccentricity. Method: 45 subjects participated in this study, 24 emmetropes, 18 myopes and three hyperopes. All subjects were free of ocular abnormalities and had no media opacities. All the subjects had normal ocular health and good visual acuity of 1.0 or better for both distance and near. The values for eccentricity and corneal radius of curvature were obtained by using a Topcon CA-100F Corneal Analyzer. Results: For the 4.5 mm zone the only significant correlation between corneal radius of curvature and eccentricity was obtained for the mean of the meridian (p = 0.007). On the other hand, we found no significant correlation for the average of two meridians or for meridian 1 and meridian 2 separately in the 8.0 mm zone. Conclusions: We found no correlation between the corneal radius of curvature and the eccentricity for both zones. In addition, no correlation could be found between the spherical equivalent of the refractive errors and the corneal eccentricity. The reason for not finding any significant correlation between the two entities could be due to factors such as smaller sample size and poor distribution of refractive errors in the sample. Moreover, there may be other factors that could influence the overall corneal shape like eye shape, axial length and corneal diameter, which was not evaluated in this study.

<strong>Purpose:</strong> Although orthokeratology (non-surgical corneal reshaping, Corneal Refractive Therapy, CRT®) has been used for almost a half century, contemporary CRT's outcomes and mechanisms still require investigation. A series of studies was designed to examine different aspects of non-surgical corneal reshaping for myopic and hyperopic corrections, including the efficacy and stability of this procedure, the effect of the lens material characteristics (Dk/t), and the corneal or superficial structural change (e. g. corneal/epithelial thickness) in corneal reshaping. <br /> <strong>Methods:</strong> In the CRT® for myopia (CRT1) study, 20 myopes wore CRT® lenses on one eye and control lenses on the contralateral eye (eye randomized) for one night while sleeping. Corneal topography and refractive error were measured the night prior to lens insertion, immediately after lens removal on the following morning and at 20 and 60 minutes and 3, 6 and 12 hours later. In the CRT® for hyperopia (CRTH) study, 20 ametropes wore CRT®H lenses on one eye for one night while sleeping, the contralateral eye (no lens wear) served as control (eye randomized). Corneal topography, aberrations and refractive error were measured the night prior to lens insertion, immediately after lens removal on the following morning and at 1 and 3, 6, 12 and 28 hours later. In the relatively long term (4 weeks) CRT® for myopia (CRT2) study, 23 myopes wore CRT® lenses overnight and removed their lenses on awakening. Visual Acuity (VA), subjective vision, refractive error, aberrations, and corneal topography were measured at baseline, immediately after lens removal on the first day and 14 hours later, and these measurements were repeated on days 4, 10, and 28. The treatment zone size was demarcated by the change in corneal curvature from negative to positive and vice versa, using tangential difference maps from the corneal topographer. In the study of effects of Dk/t on CRT® for myopia (CRTHDK), 20 myopic subjects were fit with Menicon Z (MZ) lenses (Dk/t=90. 6, Paragon CRT®) on one eye and an Equalens II (EII) CRT® lenses (Dk/t=47. 2) on the contralateral eye (eye randomized). Corneal topography, refractive error and aberrations were measured before lens insertion (baseline), and the following day after overnight lens wear, on lens removal and 1, 3, 6, 12 hours later. In the study of short term effects of CRT® for myopia and hyperopia (STOK), 20 ametropes wore CRT® and CRT®H lenses in a random order on one eye (randomly selected). The lenses were worn for 15, 30 and 60 minutes (randomly ordered, with each period taking place on a different day). Refractive error, aberrations, corneal topography, and corneal/epithelial thickness (using OCT) were measured before and after lens wear. The measurements were performed on the control eyes at 60 minutes only. <br /> <strong>Results:</strong> In the CRT1 study, after one night of CRT® for myopia, the central cornea flattened and the mid-periphery steepened, and myopia reduced. In the CRTH study, after one night of CRT® for hyperopia, the central cornea steepened and the para-central region flattened, myopia was induced or hyperopia was reduced, all aberrations except for the astigmatism increased and signed spherical aberration (SA) shifted from positive to negative. In the CRT2 study, after 4 weeks of CRT® lens wear, in general, the treatment zones stabilized by day 10, vision improved, myopia diminished, total aberration and defocus decreased and higher order aberrations (HOAs) including coma and SA increased. The visual, optical and subjective parameters became stable by day 10. In the CRTHDK study, after one night of CRT® (MZ vs. EII) lens wear, the central corneal curvature and aberration were similar with a slight exception: The mid-peripheral corneal steepening was greater in the EII (lower Dk/t) lens-wearing eyes compared to the MZ (higher Dk/t) eyes. In the STOK study, after brief CRT® and CRT®H lens wear, significant changes occurred from the 15 minutes time point: The corneal shape and optical performance changed in a predictable way; the central cornea swelled less than the mid-periphery after CRT® lens wear, whereas the central cornea swelled more than the para-central region after CRT®H lens wear; the central epithelium was thinner than the mid-periphery after CRT® lens wear and was thicker than the para-central region after CRT®H lens wear. <br /> <strong>Conclusion:</strong> After one night of lens wear, CRT® and CRTH® lenses were effective for myopia and hyperopia correction, respectively. In the 4 week CRT study, the treatment zone size changed during the first 10 days. Its size was associated with VA, refractive error, aberrations, and subjective vision. In the CRTHDK study, after one night of lens wear, changes in corneal shape were slightly different, with more mid-peripheral steepening in the lower Dk lens-wearing eyes compared to the higher Dk lens-wearing eyes. Changes in central corneal shape and optical performance were similar in both eyes. In the STOK study, CRT® lenses for myopia and hyperopia induced significant structural and optical changes in as little as 15 minutes. The cornea, particularly the epithelium, is remarkably moldable, with very rapid steepening and flattening possible in a small amount of time.

<strong>Purpose:</strong> Although orthokeratology (non-surgical corneal reshaping, Corneal Refractive Therapy, CRT®) has been used for almost a half century, contemporary CRT's outcomes and mechanisms still require investigation. A series of studies was designed to examine different aspects of non-surgical corneal reshaping for myopic and hyperopic corrections, including the efficacy and stability of this procedure, the effect of the lens material characteristics (Dk/t), and the corneal or superficial structural change (e. g. corneal/epithelial thickness) in corneal reshaping. <br /> <strong>Methods:</strong> In the CRT® for myopia (CRT1) study, 20 myopes wore CRT® lenses on one eye and control lenses on the contralateral eye (eye randomized) for one night while sleeping. Corneal topography and refractive error were measured the night prior to lens insertion, immediately after lens removal on the following morning and at 20 and 60 minutes and 3, 6 and 12 hours later. In the CRT® for hyperopia (CRTH) study, 20 ametropes wore CRT®H lenses on one eye for one night while sleeping, the contralateral eye (no lens wear) served as control (eye randomized). Corneal topography, aberrations and refractive error were measured the night prior to lens insertion, immediately after lens removal on the following morning and at 1 and 3, 6, 12 and 28 hours later. In the relatively long term (4 weeks) CRT® for myopia (CRT2) study, 23 myopes wore CRT® lenses overnight and removed their lenses on awakening. Visual Acuity (VA), subjective vision, refractive error, aberrations, and corneal topography were measured at baseline, immediately after lens removal on the first day and 14 hours later, and these measurements were repeated on days 4, 10, and 28. The treatment zone size was demarcated by the change in corneal curvature from negative to positive and vice versa, using tangential difference maps from the corneal topographer. In the study of effects of Dk/t on CRT® for myopia (CRTHDK), 20 myopic subjects were fit with Menicon Z (MZ) lenses (Dk/t=90. 6, Paragon CRT®) on one eye and an Equalens II (EII) CRT® lenses (Dk/t=47. 2) on the contralateral eye (eye randomized). Corneal topography, refractive error and aberrations were measured before lens insertion (baseline), and the following day after overnight lens wear, on lens removal and 1, 3, 6, 12 hours later. In the study of short term effects of CRT® for myopia and hyperopia (STOK), 20 ametropes wore CRT® and CRT®H lenses in a random order on one eye (randomly selected). The lenses were worn for 15, 30 and 60 minutes (randomly ordered, with each period taking place on a different day). Refractive error, aberrations, corneal topography, and corneal/epithelial thickness (using OCT) were measured before and after lens wear. The measurements were performed on the control eyes at 60 minutes only. <br /> <strong>Results:</strong> In the CRT1 study, after one night of CRT® for myopia, the central cornea flattened and the mid-periphery steepened, and myopia reduced. In the CRTH study, after one night of CRT® for hyperopia, the central cornea steepened and the para-central region flattened, myopia was induced or hyperopia was reduced, all aberrations except for the astigmatism increased and signed spherical aberration (SA) shifted from positive to negative. In the CRT2 study, after 4 weeks of CRT® lens wear, in general, the treatment zones stabilized by day 10, vision improved, myopia diminished, total aberration and defocus decreased and higher order aberrations (HOAs) including coma and SA increased. The visual, optical and subjective parameters became stable by day 10. In the CRTHDK study, after one night of CRT® (MZ vs. EII) lens wear, the central corneal curvature and aberration were similar with a slight exception: The mid-peripheral corneal steepening was greater in the EII (lower Dk/t) lens-wearing eyes compared to the MZ (higher Dk/t) eyes. In the STOK study, after brief CRT® and CRT®H lens wear, significant changes occurred from the 15 minutes time point: The corneal shape and optical performance changed in a predictable way; the central cornea swelled less than the mid-periphery after CRT® lens wear, whereas the central cornea swelled more than the para-central region after CRT®H lens wear; the central epithelium was thinner than the mid-periphery after CRT® lens wear and was thicker than the para-central region after CRT®H lens wear. <br /> <strong>Conclusion:</strong> After one night of lens wear, CRT® and CRTH® lenses were effective for myopia and hyperopia correction, respectively. In the 4 week CRT study, the treatment zone size changed during the first 10 days. Its size was associated with VA, refractive error, aberrations, and subjective vision. In the CRTHDK study, after one night of lens wear, changes in corneal shape were slightly different, with more mid-peripheral steepening in the lower Dk lens-wearing eyes compared to the higher Dk lens-wearing eyes. Changes in central corneal shape and optical performance were similar in both eyes. In the STOK study, CRT® lenses for myopia and hyperopia induced significant structural and optical changes in as little as 15 minutes. The cornea, particularly the epithelium, is remarkably moldable, with very rapid steepening and flattening possible in a small amount of time.

Submitted by (edna.saturno@ufrpe.br) on 2016-10-06T16:32:53Z No. of bitstreams: 1 Fabio Luiz Silva Pina.pdf: 1678514 bytes, checksum: add96ec2da4d0e8edf4922a29af1bb8c (MD5) / Made available in DSpace on 2016-10-06T16:32:53Z (GMT). No. of bitstreams: 1 Fabio Luiz Silva Pina.pdf: 1678514 bytes, checksum: add96ec2da4d0e8edf4922a29af1bb8c (MD5) Previous issue date: 2007-02-05 / Corneal endotelium cells present the important function of osmotic pump and barrier, thus keeping it transparent. The loss of these cells, either by any reason, becomes the cornea cloudy, influencing negativety in the visual capacity of the individual. For this fact, the conservation of corneas for transplant ends has evolved sufficiently to the long one of the years. Had to the characteristics desirable physicist-chemistries and the low cost of the coconut water, the aim of this work was to investigate the possibility of the use of the coconut water as nutritious medium in corneal preservation medium. A total of 9 cats, without no corneal pathology in course, had been sacrified. One cornea of each pair was evaluated immediately, being the other evaluated after preservation on the medium with coconut on days 3, 7 and 14. The corneas had been processed for optic microscopy. The corneas had become impracticable since day 3 of conservation, having presented morphologic alterations, signals of cellular death and estromal thickness increased, indicating important edema. We conclude that the coconut water did not serve as nutritious medium for corneal storage medium of domestic felines, however the corneas, due to absence of contamination of the medium, can be used in tectonic transplants and lamellar keratoplasty. / As células do endotélio corneal apresentam a importante função de bomba osmótica e barreira, mantendo assim a córnea transparente. A perda destas células, seja por qualquer motivo, tornam a córnea opaca, influenciando negativamente na capacidade visual do indivíduo. Por este fato, a conservação de córneas para fins de transplante tem evoluído bastante ao longo dos anos. Devido às características físico-químicas desejáveis e ao baixo custo da água de coco, o objetivo deste trabalho foi investigar a possibilidade do uso da água de coco como meio nutritivo em conservantes de córnea. Um total de 9 gatos, sem nenhuma patologia corneal em curso, foram eutanasiados. Uma córnea de cada par foi avaliada imediatamente, sendo a outra avaliada após a preservação no meio com água de coco nos dias 3, 7 e 14. As córneas foram processadas para microscopia óptica. As córneas tornaram-se inviáveis a partir do dia 3 de conservação, apresentando alterações morfológicas, sinais de morte celular e espessura estromal aumentada, indicando edema importante. Concluiu-se que a água de coco não serviu como meio nutritivo para conservantes de córneas de felinos domésticos, porém as córneas, devido à ausência de contaminação do meio, podem ser utilizadas em transplantes tectônicos e ceratoplastias lamelares.

Yes / There is an evolution in the demands of modern ophthalmology from descriptive findings to assessment of cellular level changes by using in vivo confocal microscopy. Confocal microscopy, by producing grey-scale images, enables a microstructural insight into the in vivo cornea in both health and disease, including epithelial changes, stromal degenerative or dystrophic diseases, endothelial pathologies, and corneal deposits and infections. Ophthalmologists use acquired confocal corneal images to identify health and disease states and then to diagnose which type of disease is affecting the cornea. This paper presents the main features of the healthy confocal corneal layers, and reviews the most common corneal diseases. It identifies the visual signature of each disease in the affected layer and extracts the main features of this disease in terms of intensity, certain regular shapes with both their size and diffusion, and some specific region of interest. These features will lead towards the development of a complete automatic corneal diagnostic system which predicts abnormalities in the confocal corneal data sets.

Corneal ulceration with prolonged healing following Nd:YAG laser cyclophotocoagulation in dogs is a frequent complication. It is hypothesized that these corneal ulcerations may be a form of neurotrophic keratitis due to laser-induced damage to corneal innervation. Fifteen clinically normal dogs had the neodymium:yttrium aluminum garnet(Nd:YAG) laser cyclophotocoagulation performed on the left eye. Each treated eye received 100 Joules of laser energy. Corneal touch threshold (CTT) and Schirmer I tear tests (STT) were performed before the surgery and on days 1,3,5,7,9,11, and 13 post-laser treatment. Applanation tonometry was performed before surgery and twice daily for 14 days post-laser treatment. Eyes were enucleated after 14 days and corneal nerves were stained using a gold chloride technique. Major nerve bundles entering the cornea were quantitated by quadrant, using camera lucida reproductions. Nerve bundle diameters were measured using NIH image computer software on computer-scanned images. Statistical methods included repeated values for analysis of variance for CTT, STT and IOP, and a paired t-test for nerve diameters and bundles. All laser treated eyes had significantly higher CTTs (P<0.05) compared to control eyes for all measurements. Six out of fifteen dogs had evidence of ulcerative keratitis. Intraocular pressure was significantly lower in laser treated eyes compared to control eyes in the a.m. on days 2-9,and 14, and in the p.m. on days 2-11 using a Bonferroni-corrected alpha level (P<0.0039). A significant decrease of one nerve bundle per corneal quadrant was found between the laser treated and control eyes. There was no significant difference in STT or nerve bundle diameters between laser treated and control eyes. Nd:YAG laser cyclophotocoagulation effectively reduces IOP while increasing CTT. The procedure also causes a significant decrease in the number of major nerve bundles entering the cornea, but has no effect on the diameter of those bundles. These findings support the hypothesis that nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG laser cyclophotocoagulation. / Master of Science

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Submitted by (edna.saturno@ufrpe.br) on 2016-10-07T12:50:23Z No. of bitstreams: 1 Fernando Jose Xavier de Lira.pdf: 728148 bytes, checksum: 8e97658a43081f68d2680e041cb05bf2 (MD5) / Made available in DSpace on 2016-10-07T12:50:23Z (GMT). No. of bitstreams: 1 Fernando Jose Xavier de Lira.pdf: 728148 bytes, checksum: 8e97658a43081f68d2680e041cb05bf2 (MD5) Previous issue date: 2012-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / An important function of corneal endothelial cells is to provide barrier and pump to maintain tissue transparency. Therefore the purpose of this study was to investigate the RPMI tissue culture medium for mouse cornea preservation kept under refrigeration. In order to evaluate endothelium cells integrity and shape, corneas were processed, immediately after removal from medium, for light and scanning electron microscopy. Corneas became unavailable as of day 4 of storage, exhibiting morphological alterations, with cellular death characteristics and increased stromal thickness, indicating severe edema. It was concluded that RPMI medium is not viable to preserve corneas for penetrating keratoplasty, nevertheless, we believe that it may be used as a preservation medium for corneal lamellar grafts because it is maintained sterile. / As células do endotélio corneal apresentam a importante função de bomba e barreira, mantendo assim a córnea transparente.. Portanto, o propósito deste estudo foi investigar o meio de cultura de tecidos RPMI como forma de preservação de córneas de camundongos mantidas sob refrigeração. Imediatamente após a retirada do meio de preservação, as córneas foram processadas para microscopia de luz e eletrônica de varredura para análise da integridade e forma da célula endotelial. As córneas tornaram-se inviáveis a partir do dia 4 de conservação, apresentando alterações morfológicas, sinais de morte celular e espessura estromal aumentada, indicando edema importante. Concluiu-se que o meio RPMI não é viável pra conservação de córneas com a finalidade de ceratoplastia penetrante, embora, acreditamos que por se manter estéril poderá ser usado para enxertos lamelares.

BACKGROUND: Fungal corneal ulcer is one of the major causes of visual impairment worldwide. Treatment of fungal corneal ulcer mainly depends on anti-fungal agents. In the current study, we developed an integrated combination therapy of cryotherapy and anti-fungal agents to facilitate effective treatment of fungal corneal ulcer. METHODS: Rabbit models of cornea infection were established using a combined method of intrastromal injection and keratoplasty. After treatment with cryotherapy and anti-fungal agents, scanning electron microscopy, transmission electron microscopy, and confocal microscopy were conducted to observe changes in microstructure in the rabbits. Periodic acid Schiff A and hematoxylin and eosin staining were used for detection of histological changes. RESULTS: Continuous scanning electron microscopy and transmission electron microscopy observations showed that cryothermal treatment inhibited growth of fungal mycelium by destroying fungal cellular structures. Typical cryotherapy was effective in curing fungal corneal ulcer. Different fungi showed different susceptibilities to treatment. The curative effect of Candida albicans was the best, while that of Aspergillus fumigates was the worst. CONCLUSIONS: Our study provides a novel method of a combination of cryotherapy and anti-fungal agents for treatment of fungal corneal ulcer. This treatment could help facilitate the practice of fungal keratitis treatment in the future.

No description available.