Refractive surgery after deep anterior lamellar keratoplasty: a review of the literature.

PURPOSE: The main objective of this work is to present an updated review of the different surgical procedures for the correction of residual refractive errors following deep anterior lamellar keratoplasty (DALK) surgery. METHODS: A review of the literature was conducted using PubMed, Web of Science, and Scopus databases. The search was conducted in January 2022 and was limited to articles published in peer-reviewed journals. The information extracted from each publication included sample size, mean follow-up time, pre- and post-operative uncorrected (UDVA) and corrected distance visual acuity (CDVA), pre- and post-operative refraction and spherical equivalent (SE), safety and efficacy indexes and complications. RESULTS: Residual ametropias, mainly high astigmatism and myopia, and the resulting anisometropia are likely to occur following DALK. They become a limiting factor and may lead to unsatisfactory visual restoration, therefore affecting patients' quality of vision and life. Alternative surgical interventions may be required to treat this residual ametropia, such as corneal refractive surgery or intraocular lens implantation. A total of 47 relevant articles were studied in detail. Different refractive surgery techniques have been shown to be effective and safe for the correction of ametropia following the DALK procedure and to improve the patient's quality of vision, although more research is needed to confirm long-term results. CONCLUSION: The final refractive technique will depend on different factors, such as the amount of ametropia, the condition of the cornea or the patient's individual needs, economics, and occupational demands.

Femto-LASIK after Deep Anterior Lamellar Keratoplasty to Correct Residual Astigmatism: A Long-Term Case Series Study.

Purpose: To evaluate the long-term outcomes of femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) to correct residual astigmatism after deep anterior lamellar keratoplasty (DALK). Methods: This retrospective case series study included 10 eyes that underwent Femto-LASIK after a DALK. The refractive error, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, thinnest corneal thickness (TCT), and central corneal thickness (CCT) were registered. The postoperative follow-up ranged between 36 and 60 months. Results: All surgeries were uneventful, with no intra- or postoperative complications. The mean UDVA (Snellen scale) rose from 0.13 ± 0.05 to 0.47 ± 0.15 six months after Femto-LASIK (p < 0.001). All cases experienced a significant improvement in UDVA. None of the eyes lost lines of CDVA, and seven eyes (70%) improved the CDVA compared to preoperative values. The refractive cylinder changed from a preoperative value of −3.88 ± 1.00 D to −0.93 ± 0.39 six months after Femto-LASIK (p < 0.0001). In eight eyes (80%), the UDVA and refractive outcomes remained stable at postoperative follow-up visits. In contrast, one eye experienced a refractive regression over the follow-up. TCT and CCT were stable at the different postoperative follow-up visits. Conclusions: Our findings suggest that Femto-LASIK might safely and effectively corrects residual astigmatism after DALK. Despite these encouraging results, further long-term studies, including a larger number of cases, are required to confirm the safety of the procedure. The refractive stability in eyes with prior RK might be lower than for other DALK indications.

Impact of contact lens wear on NLRP3 gene expression: Implications for ocular frailty in middle-aged adults.

The inflammatory process plays a crucial role in frailty syndrome, which can appear in middle age and is associated with a poor health outcome. Consequently, gerontologists recommend screening inflammatory biomarkers in middle-aged adults to detect frailty and, therefore, prevent chronic diseases and mortality. External factors could be a risk factor for frailty because they can generate and extend the inflammatory process. For these reasons, we analysed the effect of long-term contact lens wear on mRNA level of genes linked to inflammation (IL-6, NLRP3, NK1R, CD73, MUC16 and TRPV1 genes) in conjunctival cells of middle-aged individuals, by quantitative PCR. Middle-aged contact lens wearers presented a significant increase of NLRP3 and MUC16 mRNA level as well as a decrease of CD73 mRNA level, in comparison with non-contact lens wearers. Additionally, we checked for a potential correlation between these transcript levels and clinical changes of the participants' ocular surface. Unlike molecular analysis, clinical examination fails to detect inflammation in contact lens wearers. These data suggest that long-term contact lens wear could trigger an inflammatory response in middle age orchestrated by NLRP3 inflammasome and modulated by CD73 and MUC16 proteins. Further studies are needed to confirm our gene expression findings at the protein level as well as to investigate the potential role of long-term CL wear in the onset of ocular frailty.

Repeatability of Noninvasive Keratograph 5M Measurements Associated With Contact Lens Wear.

OBJECTIVE: To assess the intrarater repeatability of the measurements of tear meniscus height (TMH), noninvasive keratograph tear break-up time (NIKBUTs), and ocular redness measurements obtained with the Keratograph 5M (K5M) in a sample of soft silicone hydrogel contact lens (CL) wearers over 15 days. METHODS: Prospective study over two consecutive weeks. Three measurements of TMH, NIKBUTs (NIKBUT first and NIKBUT average), and ocular redness were obtained in different sessions; the first day (baseline, at 8 hr of wear, and after lens removal) and the last day of wear-15th day (at 8 hr of wear and after lens removal). The repeatability of measurements were assessed by two intraclass correlation coefficient (ICC) forms; single measurement [ICC (2,1)] and multiple measurements (k=3) [ICC (2, k)]. RESULTS: Sixty-four eyes were analyzed. The repeatability of baseline TMH [ICC (2,1) greater than 0.90; coefficient of repeatability (CR)=0.06 mm] and after and during CL wear [ICC (2,k) greater than 0.90; CR≤0.07 mm] were excellent. The repeatability of baseline NIKBUT average [ICC (2,k)=0.89 (0.82-0.93); CR=6.07 sec] was maintained after CL removal but was poorer during CL wear. The repeatability of baseline NIKBUT first [ICC (2,k) =0.80 (0.69-0.87); CR=8.74 sec] was maintained after CL removal and during CL wear at moderate-good level. CONCLUSIONS: Intrarater repeatability of TMH, NIKBUTs, and ocular redness performed by K5M after CL wear remains stable when three measurements are performed. However, intrarater repeatability during CL wear decreased only for NIKBUT average and was not affected by time of use (15 days).

Visual performance of four simultaneous-image multifocal contact lenses under dim and glare conditions.

OBJECTIVE: To assess and compare the effects of four simultaneous-image multifocal contact lenses (SIMCLs), and those with distant-vision-only contact lenses on visual performance in early presbyopes, under dim conditions, including the effects of induced glare. METHODS: In this double-masked crossover study design, 28 presbyopic subjects aged 40 to 46 years were included. All participants were fitted with the four different SIMCLs (Air Optix Aqua Multifocal [AOAM; Alcon], PureVision Multifocal [PM; Bausch & Lomb], Acuvue Oasys for Presbyopia [AOP; Johnson & Johnson Vision], and Biofinity Multifocal [BM; CooperVision]) and with monofocal contact lenses (Air Optix Aqua, Alcon). After 1 month of daily contact lens wearing, each subject's binocular distance visual acuity (BDVA) and binocular distance contrast sensitivity (BDCS) were measured using the Functional Visual Analyzer (Stereo Optical Co., Inc.) under mesopic conditions (3 candela [cd]/m) both with no glare and under the 2 levels of induced glare: 1.0 lux (glare 1) and 28 lux (glare 2). RESULTS: Among the SIMCLs, in terms of BDVA, AOAM and PM outperformed BM and AOP. All contact lenses performed better at level without glare, followed by Glare 1, and with the worst results obtained under glare 2. Binocular distance contrast sensitivity revealed statistically significant differences for 12 cycles per degree (cpd). Among the SIMCLs, post hoc multiple comparison testing revealed that AOAM and PM provided the best BDCS at the three luminance levels. In both cases, BDVA and BDCS at 12 cpd, monofocal contact lenses outperformed all SIMCL ones at all lighting conditions. CONCLUSIONS: Air Optix Aqua Multifocal and PM provided better visual performance than BM and AOP for distance vision with low addition and under dim conditions, but they all provide worse performance than monofocal contact lenses.

Optical quality of aspheric toric intraocular lenses at different degrees of decentering.

PURPOSE: To analyze the optical quality of aspheric toric intraocular lenses (IOLs) at different degrees of decentering. METHODS: Wavefront aberrations of Acrysof IQ Toric IOLs (SN6AT3, SN6AT4, and SN6AT5; Alcon Laboratories Inc, Fort Worth, TX, USA) for different powers (15.00, 20.00 and 23.50 diopters [D]) and for different degrees of decentering (diagonal, horizontal, and vertical decentering of 0.3 and 0.6mm) were measured in vitro at 3- and 5-mm pupils. The Zernike coefficients of trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. The point spread functions (PSFs) and modulation transfer function (MTF) of each IOL evaluated were calculated from the wavefront aberrations. RESULTS: Coma aberration increased significantly with IOL decentration. Statistically significant differences were found between centered and all decentered positions in coma aberration (p < 0.05). Although, we only found visible differences between centered and decentered positions in PSF images and MTF curves for horizontal and vertical 0.6 mm of decentering at 3- and 5-mm pupil. CONCLUSIONS: Despite the coma increment, these values were clinically negligible and have no effect on visual performance, except for vertical and horizontal 0.6 mm of decentering, which could have a negative effect on visual quality.

Optical performance of two new trifocal intraocular lenses: through-focus modulation transfer function and influence of pupil size.

BACKGROUND: To compare the in vitro optical quality of two new trifocal intraocular lenses at different focal points as a function of pupil size. METHODS: Two intraocular lenses having different design approaches were evaluated: the AT LISA tri 839MP with a trifocal diffractive design, and the FineVision, which combines two distinct apodized bifocal diffractive profiles resulting in three foci. A PMTF optical bench was used to assess the intraocular lenses' performance, and as optical quality metrics, the through-focus modulation transfer function was selected; that is, it was measured at 10 focal points and for four different apertures (2.0, 3.0, 3.75 and 4.5 mm). RESULTS: For both lenses, the through-focus curve showed three peaks, corresponding to far, intermediate and near focal point. At the 0.0 D focal point, the FineVision yielded better results for larger pupils. At the -1.5 D focal point, both lenses performed worse for larger pupils. At the -3.0 D, the FineVision provided better results for all apertures. However, at the -3.5 D focal point, it was the AT LISA tri 839MP that outperformed the FineVision for larger pupils. CONCLUSIONS: The two trifocal intraocular lenses under analysis have modulation transfer function peaks that correspond to the far, intermediate and near focal points. For larger pupil sizes, the FineVision seems to provide better results at far focal points, while the AT LISA tri 839MP not only provides better results at the intermediate and near focal points, but is also less pupil size-dependent.

Evaluation of repeatability and agreement of two optical biometers for intraocular lens power calculation.

The repeatability of two biometers (Lenstar-LS900 and Eyestar-900) to measure ocular parameters and intraocular lens (IOL) power calculation, and their agreement were evaluated. 134 eyes of 134 participants were measured thrice with each biometer. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and keratometry (K) were evaluated. The IOL power was calculated using different formulas. The repeatability limit (RLimit), the mean differences (MD) and the limits of agreement (LoA) were calculated. The RLimits for all parameters were higher with Lenstar compared to Eyestar. RLimits were lower than 0.50 D except for Barrett Universal II (0.54 D) and Haigis (0.51 D) formulas with the Lenstar. Mean differences were lower than 0.01 mm for AL, ACD and LT, and lower than 0.03 D for K. MD ranged from 0 to 0.02 D for all formulas except for Barrett and Hill. When dividing the sample into subgroups (short, normal and long eyes), the MDs were similar for the IOL power and were lower than 0.03 D, except for the Barrett and Hill formulas. Both biometers provide repeatable biometry and IOL power calculations. The LoA interval for the IOL power calculation was between 0.75 and 1.50D, which was similar among the subgroups.

Triple Procedure: A Stepwise Combination of Deep Anterior Lamellar Keratoplasty and Cataract Surgery.

PURPOSE: The aim of this study was to evaluate clinical outcomes of the combined surgery (triple procedure) of deep anterior lamellar keratoplasty (DALK), phacoemulsification, and intraocular lens (IOL) implantation using a new surgical strategy. METHODS: The study included 43 eyes of 43 patients who underwent a triple procedure. Twenty-six eyes with good visibility through the cornea underwent phacoemulsification before the stromal dissection. Seventeen eyes with bad visibility underwent the DALK procedure first until achieving enough visibility to perform the lensectomy. IOL power calculation was performed for a postoperative estimated flat keratometry of 43.5 and aiming to avoid hyperopic postoperative refraction. The postoperative visual examination included uncorrected and corrected distance visual acuity (CDVA) measurements and manifest refraction. RESULTS: The mean follow-up time after suture removal was 3.06 ± 2.14 years. Mean CDVA significantly changed from 0.86 ± 0.56 logMAR preoperatively to 0.37 ± 0.28 logMAR in the last visit ( P < 0.0001). The percentage of eyes with CDVA ≤0.3 logMAR changed from 6.9% preoperatively to 62.8%. No eyes lost lines of vision after surgery, and 80% experienced an improvement of 2 or more lines. The safety index was 2.2. The mean postoperative refractive sphere was +0.13 ± 2.04 D, and the postoperative refractive cylinder was -4.02 ± 2.24 D. Only 2 cases (4.65%) obtained postoperative hyperopic astigmatism. No intraoperative complications were found. CONCLUSIONS: Combined surgery of DALK, phacoemulsification, and IOL implantation is an effective and safe procedure. Depending on the corneal transparency, different surgical strategies can be established to provide more efficacy and safety.

Optical quality differences between three multifocal intraocular lenses: bifocal low add, bifocal moderate add, and trifocal.

PURPOSE: To compare the in vitro optical quality at different focal points of two new bifocal intraocular lenses (IOLs) and one new trifocal IOL. METHODS: The AcrySof ReSTOR SV25T0 (+2.5 diopter [D] add) and the AcrySof ReSTOR SN6AD1 (+3.0 D add) with two main foci (Alcon Laboratories, Fort Worth, TX) and the AT LISA tri 839MP with three main foci (Carl Zeiss Meditec, Dublin, CA) were evaluated. The optical quality of the IOLs was measured with the PMTF optical bench (LAMBDA-X, Nivelles, Belgium). The optical quality of the IOLs was quantified by the modulation transfer function (MTF) at five different focal points (0.0, -1.5, -2.0, -2.5, and -3.0 D) and for 3.0- and 4.5-mm apertures. The through-focus MTF of the IOLs was also recorded. RESULTS: For the 0.0 D focal point, the AcrySof ReSTOR (+2.5 D add) obtained the highest MTF values for all apertures. For the -2.5 D focal point, the AcrySof ReSTOR (+3.0 D add) showed the highest MTF values for 3.0 mm. For the -3.0 D focal point at 3.0- and 4.5-mm aperture, the best values were obtained with the AcrySof ReSTOR (+3.0 D add) and the AT LISA, respectively. For the -1.5 D focal point, the trifocal IOL provided better values. For the -2.0 D focal point, all IOLs provided comparable results. The through-focus MTF curves showed three and two peaks for the trifocal and bifocal IOLs, respectively. CONCLUSIONS: The trifocal IOL provides a better optical quality at the -1.5 D focal point. However, the optical quality of the trifocal IOL significantly decreases compared to the bifocal IOLs at far distance and -2.5 D focal points.

Inferior intrastromal corneal ring segments in paracentral keratoconus with no coincident topographic and coma axis.

PURPOSE: To assess the visual and refractive outcomes of implantation of intrastromal corneal ring segments (ICRS) in keratoconic eyes with no coincident topographic and comatic axes. METHODS: Forty-one keratoconic eyes of 39 patients with no coincident topographic and comatic axes were implanted inferiorly with a Ferrara-type ICRS (Keraring SI6; Mediphacos Inc., Belo Horizonte, Brazil) of 150° of arc with a thickness of 150, 200, and 250 µm. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal coma-like root mean square, and residual refractive errors analyzed using vector analysis were recorded before and 6 months after the ICRS implantation. RESULTS: Mean UDVA was 0.76 ± 0.41 logMAR before and 0.53 ± 0.46 logMAR after surgery (P = .0006). CDVA was 0.13 ± 0.14 logMAR before and 0.07 ± 0.09 logMAR after surgery (P = .0007). Two eyes (4.9%) lost two lines or more of CDVA, 3 eyes (7.32%) lost one line, 16 eyes (39.02%) had no change in CDVA, 9 eyes (21.95%) gained one line, and 11 eyes (26.83%) gained two lines or more of CDVA. The safety index was 1.10. Spherical equivalent was significantly reduced after ICRS implantation (P < .001). Corneal coma-like root mean square changed from 0.80 ± 0.53 µm before surgery to 0.61 ± 0.59 µm after surgery (P = .02) for 4.5 mm of pupil size. CONCLUSIONS: One Ferrara-type ICRS of 150° of arc with a thickness of 150, 200, or 250 µm implanted inferiorly may reduce both astigmatism and corneal coma-like aberrations in keratoconic eyes with no coincident topographic and comatic axes, providing an improvement of UDVA and CDVA values.

Diurnal variations in visual performance for disposable contact lenses.

PURPOSE: The purpose of this study is to compare the visual performance provided by different daily disposable contact lenses and to analyze its variation over time. METHODS: Visual performance was evaluated in terms of visual acuity (VA) and contrast sensitivity (CS) in 15 myopic subjects (-0.50 to -4.00 diopters) who had been previously fitted with each one of the following seven types of soft contact lenses: DAILIES TOTAL1 (Alcon, Forth Worth, TX), DAILIES AquaComfort Plus (Alcon), 1-DAY ACUVUE TruEye (Johnson & Johnson Vision Care, Jacksonville, FL), 1-DAY ACUVUE MOIST (Johnson & Johnson Vision Care), SofLens daily disposable (Bausch & Lomb, Rochester, NY), Proclear 1 Day (CooperVision, Fairport, NY), and Clariti 1-Day (Sauflon, Twickenham, United Kingdom). We measured VA at three contrast levels (10%, 50%, and 100%) and CS for three spatial frequencies (10, 20, and 25 cycles/degree). These measurements were performed at 2-hr intervals during a 12-hr period of continuous wearing. Measurements were also performed with ophthalmic lenses before contact lens fitting. RESULTS: Two-way analysis of variance (ANOVA) results revealed significant differences across the lens types and over time for low-contrast VA only. For high- and medium-contrast VA, ophthalmic lens performed better than the contact lenses after 12 hr of use (without statistical differences among the contact lenses). Contrast sensitivity values also showed differences across lenses for the three spatial frequencies under analysis. For each particular lens type, no CS variations were observed with wearing time. Although some of the differences were not statistically significant, we found that, for many of the VA and CS measures, ophthalmic lens and DAILIES TOTAL1 yielded better values than the 1-DAY ACUVUE TruEye and Clariti 1-Day. CONCLUSIONS: Assessing VA at different contrasts and CS measurements allowed us to perform a visual function evaluation. Contact lens characteristics such as material and water content, among others, may be the cause of the differences in visual performance that emerged from this study. Our findings provide useful information for contact lens practitioners.

Visual performance of two simultaneous vision multifocal contact lenses.

PURPOSE: To evaluate and compare the visual performance of two simultaneous vision multifocal contact lenses (CLs). METHODS: In this cross-over study design 20 presbyopic subjects were fitted with two different simultaneous vision multifocal CLs (the PureVision Multifocal Low Add and Acuvue Oasys for Presbyopia) in random order. After 1 month, binocular distance visual acuity (BDVA) under photopic (85 cd/m(2)) and mesopic (3 cd/m(2)) conditions, binocular near visual acuity (BNVA), binocular distance contrast sensitivity function (CSF) under photopic and mesopic conditions, binocular near CSF and defocus curve were measured. Subjects were then refitted with the alternative correction and the procedure was repeated. RESULTS: Mean BDVA under photopic conditions was similar for the Acuvue Oasys for Presbyopia and PureVision Multifocal Low Add: 0.01 ± 0.08 and 0.00 ± 0.08 logMAR, respectively (P = 0.45). Under mesopic conditions the values of BDVA were 0.20 ± 0.58 and 0.11 ± 0.09 logMAR, respectively (P = 0.005). Mean BNVA was 0.20 ± 0.05 and 0.15 ± 0.08 logMAR for the Acuvue Oasys and PureVision Low Add, respectively (P = 0.06). Binocular distance CSF testing revealed no statistically significant differences between lenses under photopic, mesopic or near conditions. Both lenses provided a comparable intermediate visual acuity. CONCLUSIONS: Both simultaneous vision multifocal CLs provided adequate distance visual quality under photopic and mesopic conditions, and better visual acuity was provided under mesopic conditions for the Purevision lens. Both lenses provided adequate visual performance at intermediate distance, but the near visual acuity appears to be insufficient for early presbyopes who require a moderately demanding near visual quality.

Myopic astigmatism correction: comparison of a Toric Implantable Collamer Lens and a bioptics technique by an adaptive optics visual simulator.

PURPOSE: To compare the optical and visual quality of a simulated Toric Implantable Collamer Lens (TICL) and a bioptics technique to treat high myopic astigmatism. METHODS: An adaptive optics visual simulator was used to simulate the vision after TICL implantation and a bioptics procedure from the wavefront aberration pattern for moderate and high-myopic astigmatism. Visual acuity (VA) at different contrasts and contrast sensitivity (CS) at 10, 20 and 25 cycles degree(-1) were measured for 3 and 5-mm pupils. Modulation Transfer Function (MTF) and Point Spread Function (PSF) were calculated for a 5-mm pupil. RESULTS: At a 3-mm pupil we only found statistically significant differences in VA between the two simulated surgeries at low-contrast for moderate- and high-myopic astigmatism (p < 0.05). Statistically significant differences were found in CS at 3-mm pupil between both procedures at the highest spatial frequency for moderate-myopic astigmatism and at all frequencies for high-myopic astigmatism (p < 0.05). At a 5-mm pupil we found statistically significant differences in VA and CS between both simulated surgeries at all contrasts and frequencies evaluated for both groups (p < 0.05). In all cases VA and CS were better with the TICL than with the bioptics technique. MTFs for the bioptics technique were worse than those computed for the TICL. The TICL showed less spread out of the PSF than the bioptics procedure. CONCLUSIONS: Simulated TICL and bioptics procedures provided good optical and visual quality, although TICL implantation provided slightly better outcomes than the bioptics procedure, especially when the pupil diameter was increased.

Clinical and Aberrometric Outcomes of a New Implantable Collamer Lens for Myopia and Presbyopia Correction in Phakic Patients.

PURPOSE: To assess the clinical and aberrometric outcomes of a new Implantable Collamer Lens (EVO Viva ICL; STAAR Surgical) to correct moderate to high myopia and presbyopia. METHODS: The study included 80 eyes of 40 patients who had bilateral EVO Viva ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, presbyopic add power, binocular through-focus visual acuity, total ocular spherical aberration (SA), coma aberration, and root mean square of ocular higher order aberrations (RMS HOAs) (i-Trace Aberrometer; Tracey Technologies) for a 4.5-mm pupil size were evaluated. RESULTS: The mean binocular postoperative UDVA and CDVA were 0.09 ± 0.19 and 0.02 ± 0.03 logMAR, respectively. The postoperative spherical equivalent was -0.61 ± 0.54 diopters (D). The presbyopic add power reduced from +1.31 ± 0.74 D preoperatively to +0.44 ± 0.58 D after surgery (P < .0001). The mean visual acuity was 0.1 logMAR or better (20/25 or better) across the vergence range from +0.50 to -1.50 D, better than 0.2 logMAR (20/32 or better) up to the vergence of -2.00 D, and remained better than 0.3 logMAR (20/40 or better) up to the vergence of -2.50 D. The total ocular aberrations induced by EVO Viva ICL were -0.34 ± 0.09 µm of SA, 0.24 ± 0.18 µm of coma, and 0.26 ± 0.12 µm of RMS HOAs. CONCLUSIONS: The outcomes support that the new ICL might be a good alternative for myopia and presbyopia correction in patients aged between 45 and 55 years. Further studies are needed to evaluate the threshold lens misalignment from which the patient´s visual quality would be affected. [J Refract Surg. 2023;39(9):589-596.].

Ten-Year Follow-up of Posterior Chamber Phakic Intraocular Lens with Central Port Design in patients with low- and normal-vault.

PURPOSE: To assess the clinical outcomes and postoperative complications of the Implantable Collamer Lens (ICL) with a central port throughout ten years of follow-up in patients with low- and normal-vault. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Retrospective and comparative case series. METHODS: This study included eyes that underwent a V4c ICL implantation with ten years of follow-up. The eyes were divided into two groups according to the vault at one year postoperatively: Vault < 250 µm; and between 250 and 800 µm. Uncorrected (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), endothelial cell density (ECD), vault, complications and secondary surgeries were analysed. RESULTS: 37 and 90 eyes were enrolled in the low- and normal-vault groups. No differences in UDVA, CDVA and refraction were found between groups at ten years of follow-up. No cases developed ICL-induced anterior subcapsular opacity over the follow-up. Two (5.4%) and eight eyes (8.9%) in the low- and normal-vault-groups required ICL exchange. One (2.8%) and two eyes (2.2%) in the low- and normal-low-vault groups required excimer laser to correct residual refractive error. The IOP remained stable throughout the 10-year follow-up. The loss in ECD from the preoperative at the 10-year postoperatively was 3.8% and 4.5% in the low- and normal-vault groups (P=0.4). No pigment dispersion glaucoma or other vision-threatening complications were reported. CONCLUSIONS: This study shows the good long-term outcomes of the V4c ICL, supporting that the central hole provides safety to the procedure and prevents the potential risk associated with the low vault.

Intrastromal Corneal Ring Segments Implantation After Deep Anterior Lamellar Keratoplasty for Astigmatism Correction: Mid-term and Long-term Follow-up.

PURPOSE: The aim of this study was to assess the long-term outcomes of implanting intrastromal corneal ring segments (ICRSs) using a femtosecond laser for correcting astigmatism in patients who had previous deep anterior lamellar keratoplasty (DALK) throughout a 5-year follow-up period. METHODS: This retrospective study included 40 eyes of 40 patients with previous DALK and astigmatism ≥3.00 D who underwent Ferrara-type ICRS implantation. The manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity (logMAR), and corneal topography were recorded preoperatively and at 6, 12, 36, and 60 months postoperatively. RESULTS: The mean UDVA (logMAR scale) improved from 1.39 ± 0.55 preoperatively to 0.71 ± 0.37 at 6 months postoperatively ( P < 0.0001). The mean CDVA (logMAR) significantly improved from 0.36 ± 0.17 to 0.22 ± 0.12 at 6 months after surgery ( P < 0.0001). Both UDVA and CDVA remained unchanged throughout the follow-up ( P = 0.09). Postoperatively, no eyes lost lines of CDVA compared to preoperatively, and around 80% of the eyes gained lines of CDVA. The safety index remained stable at a value of 1.4 throughout the follow-up. The refractive cylinder decreased from -6.86 ± 2.62 D preoperatively to -2.33 ± 1.09D at 6 months postoperatively ( P < 0.0001), and subsequently, it was stable over the postoperative period ( P = 0.2). The maximum and minimum keratometry measurements significantly decreased after surgery and remained stable over the postoperative follow-up period ( P > 0.07). CONCLUSIONS: This study shows the long-term viability of Ferrara-type ICRS implantation using a femtosecond laser as a surgical alternative for astigmatism correction in post-DALK eyes.

Long-Term Follow-Up of a 150° Arc-Length Intrastromal Corneal Ring Segment Implantation in Post-LASIK Ectasia.

PURPOSE: To evaluate the outcomes of implanting a 150° arc-length intrastromal corneal ring segment (ICRS) using a femtosecond laser in patients with post-LASIK ectasia throughout a 5-year follow-up period. METHODS: This study enrolled 45 eyes of 45 patients diagnosed with post-LASIK ectasia who underwent a 150° arc-length Ferrara-type ICRS implantation. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, residual refractive errors, and root mean square (RMS) for coma-like aberration were evaluated preoperatively and at 6-, 12-, 36, and 60 months postoperatively. RESULTS: Mean UDVA (logMAR) ameliorated from 0.53 ± 0.33 preoperatively to 0.26 ± 0.24 at 6 months postoperatively (p < 0.0001). Mean CDVA improved from 0.12 ± 0.13 to 0.04 ± 0.06 (p < 0.0001). Mean UDVA and CDVA remained stable throughout the 5-year follow-up (p > 0.1). No eyes lost lines of CDVA at any follow-up visit compared to preoperatively, and most eyes gained lines. The eyes with a refractive cylinder ≤ 2.00 D varied from 26.7% preoperatively to more than 75% at all postoperative follow-up visits. The maximum keratometry was significantly flattened (p < 0.0001), and the RMS for corneal coma-like aberration was halved (p < 0.0001). 93.3% of the eyes did not show signs of disease progression or regression of the visual or refractive outcomes at any follow-up visits. CONCLUSION: These results suggest that implanting a single 150° arc-length Ferrara-type ICRS is a safe, effective and stable procedure for visual restoration in post-LASIK ectasia. In very few cases, visual and/or refractive instability was experienced throughout the follow-up.

Beam-Shaping Extended Depth of Focus Intraocular Lens: Optical Assessment With Corneas of Increasing Spherical Aberration.

PURPOSE: To assess the optical quality and halo formation of a beam-shaping extended depth-of-focus (EDOF) intraocular lens (IOL) (AcrySof IQ Vivity; Alcon Laboratories, Inc) with corneas of long-range spherical aberration (SA) such as those resulting from myopic laser ablations. METHODS: The optical quality of the EDOF IOL and a reference monofocal IOL was evaluated with three corneas (A, B, and C, with SA =+0.135, +0.290, +0.540 µm, respectively, for a 5.15-mm pupil at the IOL plane). The through-focus modulation transfer function area (MTFa) curves were obtained between -5.00 and +2.00 diopters (D) defocus range. The halo was also assessed with the three corneas. RESULTS: Through-focus MTFa curves for a 4.5-mm IOL pupil showed a slight decrease in the maximum MTFa value provided by the EDOF IOL compared to the monofocal IOL in the three corneal situations (A: 45.9 vs 38.6 units; B: 41.1 vs 33.1 units, and C: 26.9 vs 23.8 units). For the 3.0-mm pupil, the EDOF IOL also had lower maximum MTFa than the monofocal IOL; however, the depth-of-focus increased to -2.20 D. With corneas A and B, the halo induced was of low energy with both IOLs. With cornea C, the EDOF IOL created a much larger and intense halo. CONCLUSIONS: The EDOF IOL provided a good distance optical performance and an extended range of focus of approximately 2.00 D, with a halo of low intensity when evaluated with a corneal SA similar to the one induced by a low to moderate myopic ablation. With a high myopic ablation, the halo induced would be of considerable size and energy. [J Refact Surg. 2023;39(2):95-102.].

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.