|Presbyopes should not discard reading lenses just yet|
|Wednesday, 30 November 2011|
Yilmaz OF, Alagoz N, Pekel G, et al. Intracorneal inlay to correct presbyopia: long-term results. J Cataract Refract Surg 2011; 37:1275-81.
In a nutshell
The purpose of this study was to evaluate the long-term visual results of Acufocus ACI-7000 (now named Kamra) intracorneal inlay implantation in presbyopic phakic patients. The Kamra is a small ring 3.8mm in diameter and 10.0µm in thickness, with a central aperture of 1.6mm; it is made of polyvinylidene fluoride and carbon black to make it opaque. It has a 1600 random hole pattern consisting of 28µm holes. Thirty nine patients aged 45 to 60 years were enrolled. The inlay was implanted in the non-dominant eye on the stromal bed after a LASIK flap was created, or re-lifted in those who had this as a prior procedure. Four inlays had to be explanted; one due to a button hole flap and another due to a thin flap; two had refractive shifts, -2.00D in one and +3.00D in another. At the four-year follow-up, all patients had two or more lines of improvement in uncorrected near visual acuity; 96% could read J3 or better. There was no loss in distance vision (20/40 or better in all eyes). Five patients had cataract progression, with two requiring surgery but neither had any intra-operative complication.
Presbyopia is an age-related loss of crystalline lens accommodation that results in inability to focus at near distances. External devices such as spectacles or contact lenses have been used but some patients want freedom from spectacles or may be intolerant of contact lenses. Surgical approaches have involved lens-based procedures such as multifocal intraocular lenses; patients undergoing these tend to have higher expectations and more frequent dissatisfaction. Corneal based treatments include changing the refractive status of the eye by altering the anterior corneal surface by laser in situ keratomuleusis (LASIK). Alternatively, the depth of focus can be altered by an intracorneal inlay through the principle of small-aperture optics. In this small study from Istanbul some unexpected refractive surprises were encountered leading to explantation. Dry eyes were to be expected though the authors claim the incidence and degree was lower than after LASIK; the creation of a corneal pocket instead of a flap may reduce the incidence of dry eyes.
Joseph A Coleiro