Implantable collamer lens surgery in patients with primary iris and/or ciliary body cysts

The implantable collamer Lens (ICL) (STAAR Surgical Co.), which have been reported to perform well for the correction of moderate to high myopia [1‐4]. But the prevalence of primary iris and/or ciliary body cysts in myopia is common, especially in young adult or middle-aged women [5]. In the last years, primary iris and /or ciliary body cysts were hardly detected by using common ophthalmic examinations. With the development of advanced medical technique, UBM is an important investigation which could effectively excludes the differential diagnosis of some ring melanoma of the iris and multiple separate cysts of the iris pigment epithelium [6]. Primary iris and/or ciliary body cysts are usually located inferotemporally in the anterior segment, most commonly in the iridociliary sulcus [7].Though asymptomatic in nearly all cases, they may rarely enlarge or cause secondary glaucoma, corneal decompensation [8]. Because, there were no relative reports about the safety and reliability of ICL implantation in patients with iris and/or ciliary body cysts. Our research was aimed to evaluate the clinical safety and reliability of ICL surgery in patients with primary iris and/or ciliary body cysts.

A total of 108 patients (201 eyes) were included in this retrospective study. Preoperative parameters showed no statistical difference between the two groups in the terms of biometric data, UDVA, CDVA, IOP, ACD, ACV, AOD500, TIA and CT (Table 1). There were no intra-operative and postoperative ocular or systemic complications.

Compared with custom corneal laser refractive surgery or clear lens extraction surgery, the ICL surgery has been proved to have many potential advantages, including the possibility of correction of high refractive errors, maintaining the integrity of the corneal structure and accommodation of the lens, and the reversibility [3, 4]. In our study, all cases in both two groups finally gained good UDVA and also showed no serious complications, which means primary iris and/or ciliary body cysts had no direct impact on the visual outcome in ICL surgery. The diagnosis of primary iris and/or ciliary body cysts was made according to the patients’ history and clinical manifestation, after excluding other possible etiological factors that can cause secondary cysts. Most of primary iris and/or ciliary body cysts are located at the iridociliary sulcus and/or pars plicata, which mainly arise from the iris pigment epithelium [8]. In our study, we still found that almost all cysts were located at the iridociliary sulcus or pars plicata, and were predominantly distributed in the inferior and temporal quadrants. These results were well according with the finding of Kunimatsu [6]. The prevalence of primary cysts was amount to 36.11%, which was higher than 34.4% found by Wang et al. [12]. It was reported that iris-ciliary cysts were the main cause of glaucoma and closure glaucoma [13‐15] .If the patients with cysts had been implanted with ICL, the potential risk would include: (1) cysts stimulated ciliary body, causing an increase in aqueous fluid;(2) mucus and other materials produced by cysts deposited trabecular meshwork, thus preventing aqueous fluid from flowing out; (3) If the haptics of ICL just were located at the position of cysts, which might be more likely to push the root of iris forwarding and lead the anterior chamber angle becoming narrowed or closed up;(4) The haptics of ICL might cause the broken of cyst capsule, the fluid of cysts might cause serious inflammation (Fig. 3a, b). But, in the whole follow-up periods, we did not find an elevating of IOP in the eyes with cysts. The size of cysts also showed no changes. According to the study of Wang et al. [11], the cysts larger than 0.8 mm or located at iridociliary sulcus were inclined to narrow or close the corresponding angles. When compared with the eyes without cysts, the eyes with multiple and/or multi-quadrants cysts would be more likely to narrow or close the whole anterior chamber angle. But, the eyes only with unilateral single or double cysts did not show the same result. In our study, all the postoperative parameters of AOD500, ACV and TIA in 3, 6, 9, 12’o clock were proved to be significant reduced in both two groups. But, the difference between the two groups showed no statistical significant. The result also showed that the unilateral single cyst or single quadrant cysts would have no significant effect on narrowing or closing anterior chamber angle in ICL surgery. As Zhu’s [16] study, he found significant correlation between high intraocular pressure and the presence of iris-ciliary cysts, particularly the quantity and the size of the cysts. We sincerely suggest that ophthalmologists should monitor the changes of IOP and anterior chamber angle for extended follow-up periods, once the larger primary iris-ciliary cysts or multiple cysts, especially multi-quadrants cysts located at iridociliary sulcus were detected. Central vault is of crucial value for estimating the safety of ICL surgery. Excessive vault is one of risk factors to induce secondary glaucoma, and insufficient vault is responsible for the formation of anterior subcapsular cataract [17, 18]. Previous studies had defined an excellent vault was 250 to 750 μm [19]. In our study, we found that the postoperative mean vault and CE-ICL had no statistical significant between two groups. As we all known that the changes of central vault are mainly according to the difference between the size of ICL and sulcus-to-sulcus (STS) diameter, which would explain why primary iris and/or ciliary body cysts had no direct impact on the change of central vault. In our study, we found the postoperative anterior chamber angle was closed in 3’o clock positions in one eye without cysts. Form the images of UBM (Fig. 4), we observed that the central vault was more than 1.25 mm, the anterior chamber angle was closed at the location corresponding to the ICL haptic. Excessive vaults would induce secondary glaucoma, owe to persistent angle closure, pupil blocking, or pigmentary dispersion [20‐24].For all eyes, we did not find an elevating IOP in follow-up periods. We considered, whether the secondary angle closure glaucoma would be happen, which was decided by the range of closed anterior chamber angle. If only one clock position or less than one quarter anterior chamber angle was closed, the secondary glaucoma would not be happen. Besides, with a hole in the central of the lens, which reduce the risk of papillary block.

In conclusion, primary iris and/or ciliary body are not absolutely contraindication for ICL surgery. For some single cyst smaller than 1.075 mm or single quadrant cysts located at ciliary body are rare to lead some serious complications. But, for some multiple cysts, especially multi-quadrants cysts located at iridociliary sulcus, we still should remain cautions. In the future study, we would collect more samples and monitor longer follow-up periods to prove the safety and reliability of ICL surgery in patients with primary iris and/or ciliary body cysts.