The treatment of patients with high myopia has generated controversy in recent years. Optical correction of high myopia with spectacles produces image minification, optical aberrations, limited field of vision, and a poor cosmetic appearance because of the thickness of the lenses. Contact lenses largely resolve these issues, although they entail problems of intolerance and complications derived from their use. Hence, surgical procedures, such as epikeratoplasty, automated lamellar keratomileusis, excimer laser photorefractive keratectomy, laser in situ keratomileusis, phakic intraocular lens (IOL) implantation, and refractive lens exchange have been introduced to correct high myopia.
The implantation of an IOL to correct high myopia was first discussed during the 1950s by Strampelli and Barraquer. Since then, several phakic anterior chamber IOLs (ACIOL) have been developed. Worst et al performed the first implantation of the iris-claw phakic IOL.
DISCUSSION
Weill-Marchesani syndrome is a rare connective tissue disorder characterized by short stature, brachydactyly, joint stiffness, and characteristic eye abnormalities, including microspherophakia, ectopia lentis, severe myopia, and glaucoma. Both autosomal recessive and autosomal dominant modes of inheritance have been described, and a gene for the recessive Weill-Marchesani syndrome has recently been mapped to chromosome 19p13.3-p13.2.
The characteristic small, spherical shape of the lens combined with zonular laxity predisposes the eye to pupillary block and angle-closure glaucoma in Weill-Marchesani syndrome. Asaoka et al reported a case and postulated a mechanism of chronic angle closure glaucoma secondary to frail zonular fibers and spherophakia in Weill-Marchesani syndrome. In our case, gonioscopic examination revealed angle closure glaucoma as well. Our patient also had 3+phacodonesis indicative of loose zonular fibers. Although iris-claw IOLs should theoretically not disturb the angle; nasal and temporal peripheral anterior synechiae contributed to further impairment of outflow and poor control of glaucoma.
Phakic ACIOL implantation is an effective surgical procedure to correct high myopia; however, there is a concern regarding long-term endothelial cell loss. Several articles have been published to assess the effect of iris-claw lenses on endothelial cells. Menezo et al 1 studied 94 eyes of 62 patients with myopia of -7.00 diopters or higher who underwent Worst-Fechner IOL implantation. Three years after surgery, 58 eyes (61%) had an uncorrected visual acuity of 20/40 or better and the mean endothelial cell loss was 17.9% at 5 years after surgery, whereas the percentage of hexagonality and the coefficient of cell variation tended toward preoperative levels. The same group reported 4-year follow-up results and suggested that there was a slight, progressive cell loss after implantation with return of morphometric changes to the preoperative levels. They concluded that endothelial loss occurred primarily during the surgical procedure.
Landesz and coauthors reported the long-term results of the Artisan 5-mm optic iris-claw myopia lens in 67 eyes of 38 consecutive patients with preoperative myopia ranging from -5.38 to -28.00 D. With a mean follow-up of 35 months, 67.2% of the patients had a postoperative residual refraction within ±1.00 D of emmetropia. Mean endothelial cell loss was 5.5% at 6 months, 7.21% at 12 months, 9.1% at 24 months, and 10.9% at 36 months.
Although Artisan phakic IOL has been widely used around the world over the years, it only received United States Food and Drug Administration (FDA) approval in September 2004. It is called the Verisyse lens in the United States. Pop and Payette published the initial results of endothelial cell counts of 765 eyes enrolled at 25 North American sites in the FDA Ophtec clinical trial of the myopic Artisan IOL. The mean preoperative endothelial cell count was 2631 ± 442 cells/mm2. Percentage change from baseline at 6, 12, and 24 months was -0.09% ± 16.39%, -0.87% ± 16.35%, and -0.78% ± 17.41%, respectively. The decrease was not statistically significant. No relationships were noted between endothelial cell loss and patient age or implant power.
Ophtec does not advocate Artisan phakic lens implantation in eyes with an anterior chamber depth (ACD) below 2.6 mm. The current FDA approval indications for the Verisyse are for the ACD to be no less than 3.2 mm. The original ACDs are reported to be reduced by 28 to 34% after implantation. Current ACDs in our patient are 2.63 mm OD and 2.40 mm OS. Although we were not able to identify the exact model of the iris-claw lens and preoperative ACD values are not available for our case, peripheral anterior synechiae could have further reduced the anterior chamber angle depth. The surgeon should always consider ACD before implantation of a phakic ACIOL, especially in eyes that are at increased risk for glaucoma.
To the best of our knowledge, there is no report of phakic IOL implantation to correct myopia secondary to microspherophakia in Weill-Marchesani syndrome. It is possible that the lower endothelial cell count and corneal edema in the left eye could be attributable more to the dislocated phakic IOL and the additional repositioning procedure in that eye. Nevertheless, cell counts in both eyes are significantly lower than normal for such a young age, although we do not have any data regarding preoperative endothelial cell counts.
In conclusion, iris-claw phakic IOL implantation may be an effective surgical procedure to correct high myopia in select patients; however, the surgeon should consider the risk of long-term complications in such a young patient with an unusual condition.
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