|
Dr Morselli noted that the I-CARE IOL was very easy to implant, was well tolerated in the eye, and yielded good postoperative refractive results with a high optical quality. The 19 recipients of the I-CARE IOL had a mean age of 35 years, and an average preoperative spherical equivalent of -13.36 D. Mean follow-up was 13 months. Postoperatively, mean myopia was reduced to -1.23 D and astigmatism was unchanged, as the IOL was injected through a 3.2 mm clear corneal incision. Mean BCVA increased from 0.61 to 0.73. Postoperative inflammation was minimal or absent, and no pupil distortion or serious complications were encountered. However, the phakic IOL rotated in three eyes and decentred in a fourth due to undersizing, Dr. Morselli reported.
"We tried three methods for calculating IOL size, including measurement of the white-to-white diameter with a calliper, measurement of the corneal map diameter, and ultrasound biomicroscopy. The best results seemed to occur using the calliper-determined white-to-white value from which the manufacturer determines the implant size. However, based on the characteristics of this lens, we would recommend that slight oversizing may be better than undersizing in order to increase the chances that the implant will maintain a stable position in the eye," she said. Other complications included high myopia-related Fuchs macular degeneration in one eye, and glare in one patient whose pupil size exceed 6.0 mm.
Endothelial cell counts were also measured as part of the safety analysis. Over the average of 13 months of follow-up, there was a mean decrease of around 2.0 % percent from the mean pre-operative level of 2743 cells/mm3. We attribute this change in endothelial cell count to the surgery itself and not to the I-CARE IOL, which vaults only minimally in the anterior chamber. However, the safety follow-up indicates that it is also important to pay attention to pupil size when selecting patients for the I-CARE IOL in order to avoid development of disturbing glare complaints," Dr. Morselli said.
Wavefront aberrations before and after lens implantation have been studied by Roberto Bellucci MD in 10 eyes using the Topcon K9000-PW unit. He measured corneal aberrations via Placido disk topography. He measured total ocular aberrations using the Hartmann-Shack wavefront sensor component of the instrument. However, the latter data could not be obtained from all eyes, even with dilated pupils. Those difficulties were attributed to the effect of IOL reflexes.
The wavefront stdies showed mean total aberrations increased after I-CARE implantation from 0.095 microns to 0.163 microns, and there was an approximate doubling as well for the individual higher-order aberrations of coma, trefoil, and spherical aberration. However, Dr. Morselli commented that while the changes were statistically significant, they were not clinically important. The effect of I-CARE implantation on optical quality was also investigated by determining the Strehl ratio, which was found to be reduced from 0.468 to 0.154. However, that change is also not significant, she noted, as values 0.1 to 0.2 are common in pseudophakic patients."Although the Strehl ratio decreased after placement of this phakic IOL, the post-implantation value is similar to what would be measured in a pseudophakic eye. Overall, we would conclude that recipients of the I-CARE IOL maintain good optical quality and that is consistent with the high patient satisfaction we have encountered when implanting this lens."
All eyes implanted with the I-CARE IOL underwent iridectomy. The implantation of the phakic IOL is performed using topical/intracameral anaesthesia with injection of the implant through a 3.2 mm clear corneal incision into an anterior chamber filled with high molecular weight viscoelastic. Then, the foldable haptic loops are easily positioned in the angle using a phaco manipulator. "The injection of this lens is very easy and very comfortable for both the patient and the surgeon, and because it can be placed through a small incision, the surgery has the additional advantage of being astigmatism-neutral," Dr. Morselli said.
The I-CARE phakic IOL has a single piece design and is composed of a hydrophilic acrylic material. It features a 5.75-mm optic and acrylic foldable loop haptics that have a large contact area in the iridocorneal angle, 0.9-mm, to prevent angle erosion. The implant is manufactured in powers ranging from -20 D to +10 D in 0.25 D increments, and in four lengths - 12.0, 12.5, 13.0, and 13.5 mm. Simonetta Morselli MD |
