Effect of intrastromal corneal ring segments on in vivo corneal biomechanics in keratoconus: 1-year results.

PURPOSE: To evaluate the 1-year effects of the implantation of intrastromal corneal ring segments (ICRS) in keratoconus (KC) on the dynamic corneal response (DCR) parameters obtained with the Corvis. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Prospective, single-center, clinical study. METHODS: Included were patients who underwent ICRS implantation for KC over a period of 1 year. On the day of the surgery and at least 6 months after ICRS implantation, the following measurements were made: corrected distance and uncorrected distance visual acuity, corneal tomography indices with the Pentacam, biomechanically corrected intraocular pressure and the Corvis DCRs (integrated inverse concave radius, deformation amplitude ratio, stiffness parameter at first applanation, stress-strain index [SSI] and the highest concavity radius). RESULTS: 30 eyes were included with a mean follow-up time of 15 months. Statistical analysis showed that ICRS implantation induced significant improvements in corneal biomechanics measurements between preoperative and long-term follow-up as demonstrated by a significant increase in SSI (P = .003). To confirm that this difference was actually induced due to a stiffening between early postoperative (previously published) and long-term an additional t-test was done between month 1 and late follow-up which confirmed a significant stiffening in the value of SSI (P = .01). CONCLUSIONS: Patients implanted with ICRS alone for KC showed a significantly stiffer response due to increased structural support compared with preoperative values and 1 month postoperative.

The Effect of Intracorneal Ring Segments Implantation for Keratoconus on In Vivo Corneal Biomechanics Assessed With the Corvis ST.

PURPOSE: To evaluate the effect of the implantation of intracorneal ring segments (ICRS) in keratoconus on the dynamic corneal response (DCR) parameters obtained with the Corvis ST (Oculus Optikgeräte GmbH). METHODS: This prospective clinical study included patients who underwent ICRS implantation for keratoconus over a period of 1 year. On the day of the surgery and at least 1 month after ICRS implantation, the following measurements were made: corrected and uncorrected distance visual acuity, corneal tomography indices with the Pentacam (Oculus Optikgeräte GmbH), biomechanically corrected intraocular pressure (bIOP), Corvis ST DCR parameters, integrated inverse concave radius (1/R), deformation amplitude ratio (DA ratio), stiffness parameter at first applanation (SP-A1), stress-strain index (SSI), and highest concavity radius (HRC). RESULTS: Fifty-one eyes of 40 patients were included with a median follow-up time of 3 months (interquartile ratio [IQR]: 2 to 6 months). Statistical analysis showed that ICRS implantation did not affect corneal biomechanical measurements evaluated with the Corvis ST, which was demonstrated by non-significant changes in the SP-A1 (P = .637), 1/R (P = .647), HRC (P = .177), DA ratio (P = .735), and SSI (P = .501). Additionally, the results showed that bIOP measurements were not significantly affected by ICRS implantation (P = .113). CONCLUSIONS: ICRS implantation does not affect corneal biomechanical measurements in early follow-up. [J Refract Surg. 2022;38(4):264-269.].

Sequential intrastromal corneal ring segment and monofocal intraocular lens implantation for keratoconus and cataract: Long-term follow-up.

PURPOSE: To evaluate the efficacy, safety, predictability, and stability of sequential Ferrara intrastromal corneal ring segment (ICRS) and intraocular lens (IOL) implantation in patients with keratoconus and cataract. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Retrospective case series. METHODS: This study comprised patients with keratoconus and cataract who had ICRS implantation followed 6 months later by IOL implantation. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities and residual refractive errors, analyzed using vector analysis, were recorded preoperatively, 6 months after ICRS implantation, 6 months after IOL implantation, and 3 years and 5 years thereafter. RESULTS: Seventy eyes of 47 patients were studied. The mean UDVA was 1.08 logMAR ± 0.24 (SD) preoperatively, 0.95 ± 0.31 logMAR 6 months after ICRS implantation (P = .03), and 0.44 ± 0.29 logMAR 6 months after IOL implantation (P < .0001). The mean CDVA changed from 0.35 ± 0.23 logMAR before surgery to 0.28 ± 0.22 logMAR 6 months after ICRS implantation (P < .0001) and to 0.11 ± 0.16 logMAR 6 months after IOL implantation (P < .0001). The UDVA and CDVA were stable over the period after the second procedure (P > .05). The spherical equivalent (SE) and the refractive cylinder declined steeply after IOL implantation (P < .001) and then were stable (P > .05). CONCLUSION: Sequential ICRS and IOL implantation provided good visual and refractive outcomes and was an effective, safe, predictable, and stable procedure for the treatment of patients with keratoconus and cataract.

Intrastromal corneal ring segments and posterior chamber phakic intraocular lens implantation for keratoconus correction.

PURPOSE: To evaluate the efficacy, safety, and predictability of sequential implantation of Keraring intrastromal corneal ring segments (ICRS) and an Implantable Collamer Lens phakic intraocular lens (pIOL) with corneal relaxing incisions for refractive correction of keratoconus. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Cohort study. METHODS: This study comprised patients with keratoconus who had ICRS implantation followed 6 months later by pIOL implantation with corneal relaxing incisions. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities and residual refractive errors, analyzed using vector analysis, were recorded preoperatively, 6 months after ICRS implantation, and 6 months after pIOL implantation. RESULTS: The study enrolled 40 eyes (31 patients). The mean UDVA (decimal) was 0.11 Snellen ± 0.05 (SD) preoperatively, 0.18 ± 0.14 Snellen 6 months after ICRS implantation (P=.001), and 0.50 ± 0.27 Snellen 6 months after pIOL implantation (P<.0001). The mean CDVA was 0.56 ± 0.23 Snellen, 0.68 ± 0.25 Snellen, and 0.73 ± 0.20 Snellen, respectively (all P<.0001). Six months after pIOL implantation, the efficacy index was 0.88 and the safety index, 1.28. At 6 months, 65% of eyes were within ±1.00 diopter (D) of the desired refraction and 45% were within ±0.50 D. The mean spherical equivalent after pIOL implantation was -1.19 ± 1.33 D. CONCLUSION: Sequential ICRS and pIOL implantation plus corneal relaxing incisions provided good visual and refractive outcomes, indicating that it is a predictable procedure for refractive correction of keratoconus. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Bilateral implantation of the Acri.LISA bifocal intraocular lens in myopic eyes.

PURPOSE: To asses visual quality after bilateral implantation of the Acri.LISA 366D intraocular lens (IOL) (Carl Zeiss Meditec) in patients with high and low-moderate myopia. METHODS: A total of 304 eyes of 152 patients had bilateral implantation of the Acri.LISA 366D IOL. The patients were divided into 2 groups: low-moderate myopia (IOL power from 15 to 20.5 D) and high myopia (IOL power from 0 to 14.5 D). Monocular and binocular best-corrected distance visual acuity (BCVA) and best distance-corrected near visual acuity (BCNVA), binocular best distance-corrected intermediate visual acuity (BCIVA), and distance contrast sensitivity (CS) under photopic (85 cd/m2) and mesopic (5 cd/m2) conditions were determined. RESULTS: At the 6-month postoperative visit, there were no statistically significant differences in monocular and binocular BCVA (p=0.13 and p=0.22, respectively). Monocular and binocular BCNVA was comparable between the groups (p=0.26 and p=0.09, respectively). The mean binocular BCIVA changed significantly as a function of the distance of the test (p<0.01) in both groups, and there were no statistically significant differences between groups at any distance. Monocular and binocular CS under photopic and mesopic conditions was similar between both groups (p>0.01). CONCLUSIONS: Bilateral implantation of the Acri.LISA 366D in high myopic eyes provides a satisfactory full range of vision comparable to that obtained in low-moderate myopic eyes.

Posterior chamber phakic intraocular lenses after penetrating keratoplasty.

PURPOSE: To evaluate the efficacy, predictability, and safety of a phakic posterior chamber intraocular Collamer lens (ICL) after penetrating keratoplasty (PKP). SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: A myopic or toric ICL was implanted after PKP in eyes unable to wear glasses or contact lenses and for which corneal laser surgery was contraindicated. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, and endothelial cell count were recorded preoperatively and 24 months postoperatively. RESULTS: Preoperatively, the 15 eyes had myopia from -2.00 to -17.00 diopters (D) or astigmatism from -1.50 to -7.00 D. Twenty-four months postoperatively, the mean Snellen decimal UDVA was 0.51 +/- 0.30 (SD). The UDVA was 20/40 or better in 7 eyes (46.6%). The mean CDVA was 0.79 +/- 0.22. The CDVA was 20/40 or better in 12 eyes (80%) and 20/25 in 6 eyes (40%). No eye lost more than 1 line of acuity, 2 eyes gained 1 line, and 5 eyes gained more than 2 lines; 8 eyes were unchanged. The safety index was 1.58. The spherical equivalent (SE) was within +/-1.00 D in 80% of eyes and within +/-0.50 D in 66.6% of eyes. The mean postoperative SE was -0.95 +/- 1.12 D. At 24 months, the mean vault was 2.06 +/- 0.96 and the mean endothelial cell loss, 8.1%. CONCLUSION: Results indicate that phakic intraocular lens implantation is a viable treatment for myopia and astigmatism after PKP in patients for whom glasses, contact lenses, or corneal refractive surgery are contraindicated.

Optical and visual performance of diffractive intraocular lens implantation after myopic laser in situ keratomileusis.

PURPOSE: To evaluate the optical and visual quality in eyes with diffractive intraocular lenses (IOLs) after myopic laser in situ keratomileusis (LASIK). SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: The best corrected visual acuity (BCVA [distance]) at 12.5%, 25.0%, and 100% contrasts under photopic and mesopic conditions; best distance-corrected near acuity; corneal total higher-order aberrations (HOAs); and optical quality by modulation transfer function (MTF) were measured after myopic LASIK in eyes with a spherical AcrySof ReSTOR SN60D3 IOL or an aspheric Acri.LISA 366D IOL and phakic eyes (control). RESULTS: Under photopic conditions at 100% contrast, the BCVA was 0.1 logMAR or better in all groups. At 25.0% and 12.5% contrasts, there were no statistically significant differences between the aspheric IOL group and the spherical IOL or control group (P >.01). The control group had better BCVA than the spherical IOL group (P = .0002, 25.0%; P<.0001, 12.5%). Under mesopic conditions, the aspheric IOL group had better BCVA than the spherical IOL group at all contrasts (P<.01). There was no statistically significant difference between the 2 IOL groups in mean best distance-corrected near acuity or between all 3 groups in HOAs (P >.01). With 6.0 mm and 3.0 mm pupils, there were no statistically significant differences in MTF between the aspheric IOL group and the control group; both groups had better MTF than the spherical IOL group with a 6.0 mm pupil (P<.01). CONCLUSION: After LASIK, the aspheric IOL provided better visual quality and optical quality than spherical IOL under mesopic conditions (large pupil).

Visual quality after diffractive intraocular lens implantation in eyes with previous myopic laser in situ keratomileusis.

PURPOSE: To evaluate distance, intermediate, and near visual quality in eyes having diffractive intraocular lens (IOL) implantation after previous myopic laser in situ keratomileusis (LASIK). SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: Best corrected distance visual acuity at 12.5%, 25%, and 100% contrasts under photopic and mesopic conditions, best distance-corrected near visual acuity, defocus curve, and corneal higher-order aberrations (HOAs) were measured in eyes with a spherical AcrySof ReSTOR SNA60D3 IOL or aspherical Acri.LISA 366D IOL after myopic LASIK and in phakic eyes after myopic LASIK (control group). RESULTS: Under photopic conditions at 100% contrast, best corrected distance acuity was 0.1 logMAR or better in all groups. At 25% and 12.5%, there were no statistically significant differences between the Acri.LISA and AcrySof ReSTOR groups or the Acri.LISA and control groups (P >.01). The control group had better best corrected distance acuity than the AcrySof ReSTOR group (P = .0002 and P < .0001 at 25% and 12.5%, respectively). Under mesopic conditions, the Acri.LISA group had better best corrected distance acuity than the AcrySof ReSTOR group at all contrasts (P > .01). The best distance-corrected near acuity was comparable in the 2 IOL groups (P < .01). Intermediate visual acuity was statistically significantly better in the Acri.LISA group than in the AcrySof ReSTOR group (P < .01). There were no statistically significant differences in HOAs between the 3 groups (P > .01). CONCLUSIONS: Both multifocal IOLs provided good and comparable visual acuity at distance and near. However, the aspherical Acri.LISA IOL gave better intermediate visual acuity than the spherical AcrySof ReSTOR IOL.