Posted by Dr. J. R. Lacey, Therapeutic Optometrist
Crystalens AO
Premium Refractive Lens Implant
Bausch & Lomb has recently introduced their newest intraocular lens implant (IOL), the Crystalens® Aspheric Optic lens. The Crystalens® AO is the newest addition to the Crystalens line of IOL's. Crystalens is a premium refractive IOL that functions like a person's own accommodation. The other lenses are the Crystalens HD and Crystalens Five-o. The Crystalens family of lenses are the only FDA approved accommodating IOL's.
The Crystalens AO has prolate aspheric surfaces which minimizes or eliminates spherical aberration thereby providing a better quality of image for both distance and near vision compared to spherical IOL's. The Crystalens AO has zero spherical aberration so it also improves the depth of field. Unlike some "multifocal" IOL's, vision is unaffected by pupil size in this new lens.
Crystalens AO by Bausch & Lomb
The patient outcomes are more predictable with the new Crystalens AO. The new lens provides clear vision at far distances, arm's length (intermediate) distances and up close for reading smaller print. Night vision is improved in the Crystalens AO due to the enhanced contrast sensitivity. The lens itself is made of a proprietary silicone material. This lens is another great improvement to an already good line of premium refractive IOL's by Bausch & Lomb and should certainly be considered if you are having cataract surgery or are over 55 years of age and tired of wearing glasses and you want clear vision at near, far and intermediate.
Crystalens is a registered trademark of Bausch & Lomb.
The author has no financial interest in Crystalens or Bausch & Lomb.
Posted by Dr. J. R. Lacey, Therapeutic Optometrist
Thin Corneas are a Major Risk Factor for Glaucoma
A major national study called the Ocular Hypertension and Treatment Study (OHTS) proved that the thickness of the cornea is one of the most powerful predictors for the development of glaucoma. Eyes with a corneal thickness of 555 microns or less (thinner corneas) had a 300% greater risk of developing glaucoma than those eyes with a corneal thickness of 588 microns or more.
Eyes with thicker corneas show artificially higher intraocular pressure (IOP) readings when measured; and conversely, eyes with thinner corneas show artificially lower IOP readings. LASIK patients must always advise their eye doctors of their LASIK procedure so that the true IOP's can be calculated. This is perhaps the underlying issue of "normal tension (pressure) glaucoma" which accounts for 25-33% of all glaucoma patients. Normal tension glaucoma patients virtually always have thin corneas!
Ultrasonic Corneal Pachymetry
Measurement of corneal thickness is not a routinely performed test in a general vision exam. The most common test used to measure the thickness of the cornea is by ultrasonic technology (corneal pachymetry). Topical anesthetic drops are instilled on the cornea of the eye. A probe is then touched to the cornea and the reading is completed. The accuracy and reproducibility are somewhat difficult to duplicate since the corneal thickness varies and increases toward the periphery. Additionally, the probe must be perpendicular to the corneal surface for maximum accuracy.
Because corneal thickness is such an important test it should be performed at least once on everyone over the age of 40 or those with other glaucoma risk factors so your eye doctor is able to accurately assess the true intraocular pressure of your eye.
Corneal Ultrasonic
Pachymeter used to
measure corneal thickness
