Changes In Iridocorneal Angles After Evo Visian Icl Phakic Lens Implantation In Miopic Patients For Ametropia Correction

Implanting EVO Visian ICL phakic lens for ametropia correction is increasingly the technique of choice to compensate refractive errors. Once the lens is implanted in sulcus, ocular structures could be modified in their parameters. Iridocorneal angles are one of these structures, responsable for facilitating the drainage of aqueous humour from the anterior chamber into Schlemm´s Canal. Changes in the opening of these angles could be associated with the appearance of undesirable secondary phenomena. The purpose of this descriptive study is to find out how the temporal and nasal iridocorneal angles vary over time after implantation of the EVO Visian ICL lens.

Clínica Rementería. Madrid.

In this descriptive study, eyes of patients implanted with EVO Visian ICL with one-year follow-up and all operated by the same expert surgeon were analysed. The variables analysed preoperatively were Km (Mean Keratometry), WTW (White to White) and ACD from endothelium (Anterior Chamber Depth) with Pentacam; and nasal and temporal Iridocorneal Angles and CLR (Crystalline Lens Rise) with Visante OCT. Postoperatively, nasal and temporal iridocorneal angles, PV (Posterior Vault: ICL-Cristalline lens distance) and AV (Anterior Vault: ICL-Endothelium distance) were measured 1 month and 1 year after surgery also with Visante OCT. All data were processed with SPSS Software.

38 eyes of 19 patients were analysed preop and postop 1m and 1y after surgery. The PV and AV obtained 1m postop was 509.74±208.41µm and 2497.32±264.65µm respectively.The results for PV and AV 1y postop were 415.09±190.90µm and 2686.29±243.05µm respectively.The preop mean results for temporal angles were 43.579°±6.85° and for nasal angles 45.63±6.70°.1m postop mean value of temporal angles was 28.18°±5.20°;and mean value of nasal angles was 27.58±4.08°;a mean decrease of 15.43°±7.24° for temporal and 17.69±7.84° for nasal angles was observed for this period of time.1y after surgery the mean values for temporal and nasal angles were 30.91±5.23°and 29.64±5.15°,implying a reduction of 13.18±8.52° for temporal and 16.42±8.49° for nasal angles. 

PV decreases during the first year, due to the settling of the lens in the sulcus; while the AV increases, but not in the same proportion, because the PV value is affected by pupillary dynamics, accommodation and CLR. 

Temporal and nasal iridocorneal angle values are reduced after phakic lens implantation during the first month after surgery because the lens anteriorises the iridian structures causing this angular decrease; after one year after lens implantation, the iridocorneal angles tend to recover and open up; this could be explained by the increase of the AV (ICL-Endothelium distance). The angles on the temporal side tend to be more open than the angles on the nasal side.