Influence of Ocular Residual Astigmatism and Target-Induced Astigmatism on the Efficacy of the Implantation of a Toric Implantable Collamer Lens With Central Hole for Myopic Astigmatism Correction

Abstract

PurposeTo investigate the effects of ocular residual astigmatism (ORA) and target-induced astigmatism (TIA) on the efficacy of toric implantable collamer lens (TICL) with central hole for myopic astigmatism correction.MethodsRetrospective case series. One hundred and eighteen eyes implanted with a TICL (V4c) from 118 patients were included. Subjective refraction and corneal topography were examined preoperatively, at 1 and 12 months postoperatively. The eyes were divided into the low-ORA ( ≤ 0.5 D) and high-ORA (>0.5 D) groups based on vector analysis, and into the low-TIA (≥0.75D and <2 D) and the high-TIA (≥2 D and ≤ 4 D) groups according to preoperative refractive astigmatism. Correction index (CI) and index of success (IOS) were compared between different groups.ResultsAll surgeries were uneventful, and no complications occurred during follow-up. At 1 and 12 months postoperatively, no significant differences were found in CI or IOS values between the high and low ORA groups, while significantly higher CI and lower IOS were detected in the high-TIA group than in the low-TIA group (P < 0.05). No significant difference was found in CI between 1 and 12 months postoperatively in either group (P > 0.05). However, significantly lower IOS was found at 12 months compared with 1 month postoperatively for each group (P < 0.05).ConclusionsToric implantable collamer lens (TICL) implantation is effective in correcting myopic astigmatism and is more effective in eyes with high TIA, while ORA has a minor effect.

Effect of vault on predicting postoperative refractive error for posterior chamber phakic intraocular lens based on a machine learning model

“…Hence, postoperative residual astigmatism may be influenced by incision and rotation. In our previous study, postoperative incision astigmatism was approximately 0.33 D. 33 The PRAE for the OCOS calculator approached this value (0.36 D @ 102 degrees). However, PEs up to 0.5 D are not clinically significant for visual acuity and can be ignored.…”

Intraocular Implantable Collamer Lens with a Central Hole Implantation: Safety, Efficacy, and Patient Outcomes

“… 42 , 43 In patients with astigmatism, toric ICLs yielded promising results in correcting astigmatic component and were even more effective in eyes with high astigmatism (≥2 D and ≤4 D) than in those with low astigmatism (≥0.75 D and <2 D). 44 , 45 In a review of data from 1905 eyes by Packer in 2018, the weighted average efficacy index was 1.04 (range, 0.90–1.35) and weighted average postoperative uncorrected distance visual acuity (UDVA) was 20/19 (logMAR −0.02) (range, 20/12–20/27 (logMAR −0.20 to 0.14)), confirming the good refractive outcomes of the ICL. 46 In a recent US-FDA clinical trial evaluating 629 eyes of 327 participants, EVO ICL lenses achieved high levels of UDVA (−0.059 ± 0.10 logMAR), with an efficacy index of 1.06.…”

Management of low astigmatism in implantable collamer lens surgery: opposite clear corneal incisions vs toric implantable collamer lens

“…Conversely, in corrections with T-ICL, although some authors suggest that when astigmatism is low, the visual result is worse than in higher astigmatism because of the influence of ORA. 33 Other studies suggest that correction of refractive astigmatism with T-ICL is independent of the amount of ORA. 34 This study has some limitations that should be mentioned.…”