¿Es la tinción inducida por soluciones de mantenimiento REALMENTE tinción corneal?

Más abajo podrás ver el texto original, para quien quiera leer el texto en inglés, escrito por Susan J. Gromacki, OD, MS, FAAO para la publicación CL Today

Por muchos lugares hemos visto informes que dicen que con la combinación de ciertas soluciones únicas con ciertos materiales de lentes de contacto, se produce más tinción corneal inducida por la solución… Una investigación reciente de Frank Bright, PhD, sugiere que lo que vemos no es la tinci´n de brechas en el epitelio (como ocurre con la tinción patológica) sino una hiperflourescencia transitoria asociada a los conservantes, de modo que el conservante se uniría a la fluoresceina sódica y ambos se acumularían en la superficie ocular

Por otro lado, la diferencia entre el grado de tinción entre unos tipos de soluciones y otras es porque por ejemplo la PHMB interactúa con la fluoresceina hasta 50 veces más que otros conservantes, etc…

Is "Solution-Induced Corneal Staining" Really Corneal Staining?

It has been widely reported that the utilization of certain multipurpose solution (MPS)/soft contact lens material combinations, in some patients, causes more solution-induced corneal staining than others, www.staininggrid.com. But is this really true corneal staining that we are seeing?

Recent research by Frank Bright, PhD, of the University at Buffalo, State University of New York, suggests otherwise. He believes that what we are seeing is not a breach in the epithelium (i.e. pathological staining), but rather a preservative-associated transient hyperfluorescence (PATH) caused by sodiumfluorescein binding with the multipurpose solution preservative and accumulation at the ocular surface. Contact lenses themselves, while soaking in MPS, bind some of the solution's preservatives. After lens application to the ocular surface, the preservatives gradually release into the tear film. Dr. Bright concludes that the reason we see this clinical finding more prominently with polyhexamethylene biguanide (PHMB)-containing care solutions is that PHMB interacts with fluorescein as much as 50 times greater than polyquaternium-1. In addition, PHMB has a peak release time from contact lenses of about 2 hours, corresponding exactly to the time when we see the most corneal staining. There are still many other unanswered questions that need to be addressed on this topic, but it is fascinating new research...it will be interesting to see where other researchers go from here, as well as the ultimate clinical implications for our patients.

Bright FV, Maziarz P, Liu M, Zhang JZ, Merchea M. Poster presented at: The 6th Biennial Scientific Symposium of the Contact Lens Association of Ophthalmologists Education & Research Foundation; September 23-25, 2010; Las Vegas, Nevada, USA.
Bright FV, Maziarz P, Liu M, Zhang JZ, Merchea M. PHMB and PQ-1 impact on a liposome corneal surface membrane model. Invest Ophthalmol Vis Sci 2011; 52: E-abstract 6491.