JCRS October 2020
Patients with subclinical keratoconus who received the V4c ICL/toric implantable collamer lens (ICL) maintained stable refractive results with follow-up of up to two years, Chinese investigators report. A retrospective study evaluated 60 eyes of 60 patients with a mean age of 27 years. Ectasia was measured with Scheimpflug tomography (Pentacam) and Corvis ST instruments. Mean postoperative UDVA and CDVA were 20/20 and 20/18. The mean difference between the intended and achieved spherical equivalent was −0.08 ± 0.47D. The spherical equivalent was within ±1.00D of the intended correction in 57 eyes (95%), and 58 eyes (97%) had astigmatism less than 0.50D. The refractive results were stable two years postoperatively, and the corneal biomechanical parameters returned to their preoperative levels at three months. Corneal biomechanical factors were not affected by the ICL surgery with a clear corneal incision size of 2.8mm.
K Li et al., “Visual outcomes and corneal biomechanics after V4c implantable collamer lens implantation in subclinical keratoconus”, 46(10):1339-1345.
Micromonovision with bilateral toric EDOF IOLs
Toric extended depth of focus IOLs targeted for micromonovision appear to produce good functional vision and high patient satisfaction, a new study suggests. The study included 52 eyes of 26 patients with regular corneal astigmatism from 0.75 to 2.60 dioptres. Postoperative corrected distance, uncorrected distance, uncorrected intermediate, and uncorrected near visual acuities were −0.10 (±0.12), −0.01 (±0.13), 0.01 (±0.14) and 0.13 (±0.14), respectively. Mean refractive cylinder of 0.47 ± 0.46D at the three-month mark. Rotational predictability and centration were both good. Seventy-seven percent of patients reported spectacle independence, while 95% of patients were satisfied with distance and intermediate visual results. Some 70% were satisfied with their near vision results. Haloes, starbursts and glare occurred in less than 25% of cases.
S Georgiev et al., “Visual performance after bilateral toric extended depth-of-focus IOL exchange targeted for micromonovision”, 46(10):1346-1352.
Tangential curvature maps and cataract surgery IOL calculations
IOL calculation in eyes undergoing cataract surgery that have previously undergone refractive surgery continues to be a major clinical challenge. Identifying the type of ablation performed is a key step in improving outcomes in these cases. Researchers compared tangential and axial map utility in a study of 52 novice reviewers who looked at 60 total images from 30 eyes presenting for cataract surgery evaluation with known refractive surgery status. Tangential curvature maps more accurately demonstrated postoperative curvature patterns than did axial curvature maps and facilitated identification of myopic and hyperopic ablations for the novice ophthalmologists. No difference was seen in pattern recognition accuracy between Placido and Scheimpflug imaging devices, suggesting that, for pattern recognition, the devices should be equivalent.
Ravi S Shah et al., “Comparative postoperative topography pattern recognition analysis using axial vs tangential curvature maps”, 46(10):1368-1373.
