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| ARVO: Wavefront Technology e altre nuove ricerche sul KC http://www.associazionecheratocono.it/forum/viewtopic.php?f=18&t=133 |
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| Autore: | scaistar [ sabato 7 maggio 2005, 14:09 ] |
| Oggetto del messaggio: | ARVO: Wavefront Technology e altre nuove ricerche sul KC |
ARVO Meeting 1-5 Maggio 2005 http://www.arvo.org/root/index.asp Wavefront Technology and KC Two research groups are working on a soft contact lens custom design using wavefront technology. One researcher is exploring wavefront technology to determine the visual benefit of correcting high order aberration for high and low contrast visual acuity (VA) in keratoconus. The higher the order of aberration that can be corrected the sharper the image. The other group is looking at the dynamic movement of customized contact lens after blinking. This is one of the factors that reduces visual benefit of correcting higher order aberrations in the eye. The goal of this study is to theoretically investigate the feasibility of improving vision with customized contact lenses in KC eyes when dynamic decentration and rotation of the customized contact lens are taken into account. Correcting higher order aberrations provides a larger visual benefit in KC eyes than in normal eyes. Their calculations demonstrate that correcting higher order aberration with customized optics improves the retinal image quality even with the dynamic movement of customized contact lens although actual perceived vision improvement needs to be evaluated. Both studies are in the THEORETICAL stage, however these custom lathed soft lenses corrected by wavefront technology are in the future for KC. ______________________________________________ Thursday was KC Day at ARVO, 25 posters were presented covering topics from genetics to changes in curvature over time. Here is a summary of the info presented In genetics - It has long been known that there is no simple Mandelian pattern of inheritence in KC.It is mostly sporadic The mode of inheritance is difficult to establish as the disease shows variable expressivity. One group studied 148 individuals from 22 multiplex families in Ecuador with KC. Showed no linkage to any of the previously defined KC Loci. A genome wide scan is in progress. Other groups are exploring various loci...work will continue in this area for some time. Quality if vision post DLK and PK were compared and no significant difference in contrast sensitivity and HOA were found. From the CLEK Group: Prediction of Vision loss: they found that over the study period 1in 5 patients experienced a substantial reduction in visual performance in at least one eye over the 8 yr period. Predictors for a pt to experience 10 letter (2line) reduction in vision include initial best corected visdion, Steeper corneal curvature, and Voigts striae Longitudinal changes in corea curvature - CLEK subjects exhibited a slow bu clear increase in corneal curvature during the study period of 1.44 to 3 D Younger age and poorer HC (high contrast )manifest refraction visual acuity at baseline predicted the rate of change in corneal curvature. The group at Wills has developed a new device to measure IOP in KC,PMD and post transplant eyes. Dymamic Contour Tonometer (DCT) will measure IOP regardless of corneal thickness. KC and PMD usually show low IOP, glaucoma may be undiagnosed in this population. Two groups presented information abot Riboflavin and UVA - this first investigated the depth of stiffening of the cornea using pig eyes. They found the stiffening in the 200um of the anterior cornea but also in the deeper levels- the next 200um. However, 65% of the UVA is absorbed in the first 200um, and only 25% in the deeped 200um. Showing that the deeper structures and especially the endothelium are not affected. The other group reviewed human cases and determined in their study that of 27 eyes w/ mod to severe KC (>K48) topographies stabilized over 12-18 mo of the study. And concluded that Ribo/UVA may offer a promise of stabilizing of progression of KC by decreasing corneal elastisity.Their work confirms that of Wloensak: Slows or halts progression and improved UVA They found no changes in corneal or lenticular clarity, IOP or endothelial cell count. No adverse outcomes in the 12-18 mos follow up. They suggest this might be a potentioal pretreatment for PK and may allow surface eximer ablation otherwise contraindicated in KC. Two groups are studying wavefront tecnology to determine if this technology can be applied to custom lathed soft lenses. One group is looking to correct higher order aberrations for better contrast senssitivity in these lenses, the other group is working to find means of creating a customized lens that will correct the vision, but also move on the KC eye. Lots being done in KC research, lots to follow...and lots to look forward to! Cathy Warren PS: Per chi vuole tentare di capirci qualcosa.. la mezza-traduzione di Zio Google: http://translate.google.com/translate?u ... uage_tools |
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| Autore: | scaistar [ martedì 10 maggio 2005, 23:50 ] |
| Oggetto del messaggio: | |
-More news from the ARVO conference: Potential new technique for corneal transplant surgery: One research group presented information about the IntraLase laser and its use in corneal transplant surgery. The work done in the laboratory showed that corneas that underwent the procedure with IntraLase tended to show less induced astigmatism when compared with the traditional transplant group. After the laser-based transplant, suture removal may be sooner and the repaired area may be stronger than conventional transplants. Clinical trials (on humans) has not yet begun. |
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