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CrystaLens shows good potential, requires immersion biometry, surgeon says
Immersion biometry improves accuracy of results by eliminating compression errors.
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ALGARVE, Portugal – The C&C Vision AT-45 CrystaLens accommodative IOL gives excellent, long-lasting results for distance and near vision, provided that accurate immersion biometry is carried out before implantation, according to a surgeon here.
“My first implants were rather disappointing. I ended up with patients who could see well for near, but needed some degree of spectacle correction for distance vision. I was about to give it up with this lens. I then decided to try immersion biometry, and results changed dramatically,” said Carlos Moedas, MD, of the Hospital Particular do Algarve.
Immersion biometry is not used by many surgeons, he added.
“It’s time-consuming and a bit messy, so we don’t like it so much. However, I’ll never get tired of saying how important it is. It eliminates compression errors and minimizes axial alignment errors. It improves accuracy tremendously. I am using it for all types of implants now, not just for the accommodative lens,” he said.
It makes the difference
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When implanting an accommodative IOL, accuracy of results is particularly important. There is no justifying the extra cost of this lens if emmetropia is not achieved or very nearly achieved, Dr. Moedas said.
“Candidates for accommodative IOL implantation don’t want glasses,” he said.
For the same reason, he added, there is no point in offering this option to patients who are not motivated in this direction.
“If they don’t like reading, or like wearing spectacles for psychological reasons, they won’t appreciate the benefits of this lens, nor will they appreciate its price,” he said.
The first three CrystaLens patients of Dr. Moedas, implanted from November 1999, improved their visual acuities remarkably, could read J1 to J3, but had distance refraction from –1.25 D to –2 D.
“After those first disappointing results, I implanted 21 more eyes with the AT-45 IOL, but used immersion biometry for all of them. Refraction at distance is now about –0.5 D, in some cases even less. Only in one case refraction was –1 D,” he said.
Near visual acuity was measured through whatever distance correction was needed. Results are therefore underestimated, Dr. Moedas pointed out. However, more than 90% of patients could read J3, 50% could read J2 and more than 45% could read J1.
Best corrected visual acuity of 20/32 was achieved by all patients, while 75% were 20/25 and 50% were 20/20.
“These results are remarkable, taking into account that my patients were all very old. Most of them were over 70, and quite a few over 80 years old,” he said.
No complications
No intraoperative complications were reported in Dr. Moedas’ series.
“The implantation technique is not difficult to learn. At present, the lens is inserted using forceps, as an injector is not yet available, but the manufacturers are addressing it. The incision needs to be enlarged to 3.5 mm to 3.7 mm, and we can’t avoid this, because the lens doesn’t fold, and would put too much pressure if forced through a 3.2-mm incision,” he said.
Capsulorrhexis should be between 4 mm and 6 mm, and well centered, he recommended. A larger capsulorrhexis might allow the lens to shift forward and dislocate.
Atropine at the end of surgery and at day 1 is mandatory to paralyze the ciliary muscle and keep the lens in the back position while the fibrotic processes fix the loops to the capsule.
No complications were reported in the postoperative period either. Once the movements of the ciliary muscle are recovered, accommodation starts and is maintained, hopefully, forever.
“My follow-up is not long enough, but there are colleagues with longer follow-ups, even 10 years with the older designs of the lens, who report no loss or decrease of accommodation in their cases, not even if the capsules are YAGed,” Dr. Moedas said.
According to Dr. Moedas, there are studies demonstrating that the ciliary muscle increases rather than decreases its strength with age.
“These findings are confirmed by the fact that older patients have slightly better results than younger patients,” he said.
The small, 4.5-mm optical zone of the lens has not created problems in Dr. Moedas’ series.
“This might be due to the age of my patients. They rarely drive at night and, like almost everybody at their age, have small pupils. None of them has ever even mentioned halos or glare, although I can’t exclude that this could be in some cases a problem with younger patients,” he said.
A promising future
Dr. Moedas concluded by expressing his appraisal and faith in this product.
“Stuart Cumming, MD, and his team have worked for at least 10 years on this IOL, with continuous modifications. This is the seventh design, and is a remarkable little device, where every single detail has been worked to perfection,” Dr. Moedas said.
For Your Information:
- Carlos Moedas, MD, can be reached at Hospital Particular do Algarve, Alvor, Portinão, Portugal; (351) 082-420-420; fax: (351) 082-420-404; e-mail: cmoedas@mail.telepac.pt. Dr. Moedas has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- C&C Vision can be reached at 6 Journey, Suite 270, Aliso Viejo, CA 92656; (949) 916-9352; fax: (949) 716-8362.