Long-term results with phakic IOLS show favourable functional outcomes but increasing rate of cataracts
Cheryl Guttman
in Munich

Michel Gonvers	Philippe Othenin-Girard

LONGTERM follow-up of eyes implanted with the ICL indicate that it is an effective and long-lasting treatment for moderate-to-high myopia. However, while no new types of complications are emerging, the incidence of anterior subcapsular cataracts continues to increase in eyes where there is not sufficient vaulting, report Swiss researchers.

Speaking at the XXI Congress of the European Society of Cataract & Refractive Surgeons, Philippe Othenin-Girard MD presented the functional results and complications from a series of 104 eyes of 66 patients implanted with the ICL at H™pital Jules Gonin, Lausanne , Switzerland . His colleague Michel Gonvers MD focused on the safety issue of cataract formation.

Their experience with the ICL began in April 1998. Follow-up for the study group ranged from one to 4.5 years, and averaged 32.5 months. "Two years ago we reported our short-term experience with ICL implantation for the treatment of high myopia. Overall, the findings remain the same, and encouragingly we have seen no new problems with pigmentary dispersion or increasing IOP. However, the main drawback continues to relate to insufficient vaulting and the development of anterior subcapsular cataract because of that," said Dr. Othenin-Girard.

Four different forms of vaulting as visualized with the Scheimpflug camera. Total vaulting is represented in D: it combines marked central vaulting plus complete periphal vaulting.

The patients in the series had a mean age of 37.6 years (range, 10 to 62 years), mean preoperative SE was -13.6 D, and the mean power of the implanted lens was -16.5 D. Model V2 of the ICL was implanted in a single eye, 20 eyes were implanted with model V3, and 83 eyes were implanted with model V4. Of the 104 eyes, only 88 were targeted for emmetropia. For those eyes the mean SE at last visit was -0.87 D (range, -3.25 to +1.37 D); 40% of the 88 eyes were within 0.5 D of emmetropia and 62.5% were within 1.0 D.

Nearly three-fourths of the eyes targeted for emmetropia had UCVA of 20/40 or better, and in 21.6%, UCVA was 20/20 or better. The efficacy index (final UCVA/initial BCVA x 100) averaged 98.3, and it exceeded 50 in all but six eyes that were undercorrected by more than 2.0 D, Dr. Othenin-Girard reported.The safety review showed BSCVA was maintained or improved in all eyes except for two, of which one had an anterior subcapsular cataract and the other a Fuchs' spot. However, four other eyes that had developed cataracts and undergone surgery for cataract removal were not included in that analysis.

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Anterior subcapsular cataract (ASCC) observed with the Scheimflug camera. A : Retroilluminated photograph. B : Section at the level of dotted line seen on Figure 2A

At last follow-up, 27 (26%) eyes showed evidence of ICL-induced anterior subcapsular cataract (Figure 2), including eight eyes implanted with the V3 model and 19 eyes implanted with the V4 model (Figure 3). The researchers evaluated cataract formation and its relationship with ICL vaulting based on analyses of photos taken preoperatively, at three months post-implantation, and yearly thereafter. The evaluated the transparency of the crystalline lens in retroilluminated photographs from the slit-lamp or Scheimpflug camera (Figure 2). A cataract was judged to be ICL-induced if the opacity was anterior, subcapsular, and appeared in a lens that was clear at 3 months post-implantation.

Central vaulting at the last follow-up visit foe the two different models of ICL : ICLV3 and ICLV4

Central vaulting (vaulting at the centre of the optic) was measured on digitized photographs taken with the slit-lamp camera, and peripheral vaulting (vaulting at the junction of the optic and haptics) was estimated from Scheimpflug photos and graded as complete, partial/asymmetrical, or absent (Figure 1). "Lens changes noted at the first postoperative assessment at three months were considered a consequence of the surgery itself rather than of the phakic IOL," Dr. Gonvers said.

The rate of ICL-induced cataract rose with both increasing duration of follow-up and increasing patient age. While the overall rate in the 104 eye series was 26%, it was 40% among the 15 eyes followed for at least 48 months. Among patients aged 10 to 30 years old, 7% developed a cataract compared to 41% of patients 41 to 50 of age (Figure 5). Of the 77 eyes where the crystalline lens remained clear, there was total vaulting, i.e., both marked central and complete peripheral vaulting, in 24 eyes, while partial or total touch with the ICL was observed in the other 53 eyes (Figure 4). There was no statistically significant difference in vaulting between eyes implanted with the V3 versus the V4 model.The analyses showed cataracts did not develop in any eyes where central vaulting exceeded 0.15-mm and that total vaulting was always present when central vaulting exceeded 0.15-mm.

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Since the 'cataract demarcation' and 'total vaulting demarcation' lines were fused, we concluded that there is a strong link between total vaulting and cataract development. Therefore, we believe there is a strong chance that the 24 eyes where there is no contact with the ICL will remain clear in the future, while cataract will likely develop in the remaining 53," Dr. Gonvers said. He continued, "Although successive design modifications of the ICL have aimed to decrease the risk of contact with the crystalline lens, we really believe correct sizing of the ICL is much more important than the model in achieving sufficient vaulting. However, accurate sizing remains a challenge given the current use of white-to-white measurement."

Distribution of vaultings for the 27 eyes with anterior subcapsular cataracts (ASCC) and the 77 eyes with clear lenses. The total vaulting demarcation line is fused with the cataract demarcation line	Distribution of cataracts in four age groups

Highlighting that point are the results of a study presented at the ESCRS Congress by Dan Reinstein MD, in which he demonstrated a total lack of correlation between the white-to-white measurement and the true sulcus-to-sulcus distance determined using Artemis ultrasonography. "We are communicating with Staar Surgical regarding the urgency of finding a better way to calculate the sulcus-to-sulcus distance, and to that end, we have made some proposals for the development of a new technique that would be less expensive and simpler than using the Artemis instrument," Dr. Gonvers told EuroTimes.

Describing the other complications that have been encountered in the series, Dr. Othenin-Girard reported that moderate IOP elevation occurred in 17 eyes, but was transient and secondary to corticosteroid treatment. Ocular hypertension developed late in two eyes, but has responded well to topical treatment and seemed to have no relationship to other complications."Overall, mean IOP was essentially unchanged comparing the baseline and last follow-up value," Dr. Othenin-Girard said.Marked pigmentary dispersion has been noted in a single eye, while pigmentary dispersion has been visible in eight eyes and barely visible in 83 eyes. Nevertheless, the pigmentary dispersion has not progressed over time, and it has not been found to have any correlation with vaulting or ICL power.

Other postoperative complications have included peripheral bulging of one or more plates of the ICL with localized lowering of the anterior chamber in six eyes, and excessive vaulting in four eyes, of which one was treated successfully with surgical repositioning of the ICL at eight months after implantation.

Michel Gonvers MD
Professor of Ophthalmology,
Hopital Jules Gonin
michel.gonvers@ophtal.vd.ch

Philippe Othenin-Girard MD
Hopital Jules Gonin
pog@ophtal.vd.ch

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