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.

Protector Role of Intraocular Lenses under Artificial Light Conditions.

INTRODUCTION: The aim of this work was to analyze, in an in vitro model, the possible protective effects of ultraviolet- (UV-) or UV/blue-filtering intraocular lens (IOL) under light-emitting diode (LED) lighting conditions. METHODS: Ten models of IOLs were evaluated. Light transmission spectrum was recorded from 300 to 800 nm, in steps of 1 nm. Photodamage in vitro model was induced in ARPE-19 cells by blue LED light (465-475 nm). Changes in cell viability and oxidative stress variables were studied to assess the protective effect of IOLs. RESULTS: UV/blue-filtering IOLs models block blue light spectrum in different proportion and UV-filtering IOLs blocking wavelength below 400 nm. However, in vitro study under blue LED light exposure does not show protective effects related with mitochondrial dysfunction and oxidative stress of UV/blue-filtering IOLs. CONCLUSIONS: The current in vitro study suggests that UV/blue filtering IOLs are not useful in terms of photoprotection in artificial light conditions. The results obtained indicate that it is needed to give attention to other IOL parameters besides the type of filter, as it seems they could have influence on the protective role.

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.

Femtosecond laser-assisted cataract surgery in shallow anterior chamber cases.

PURPOSE: To assess the effectiveness, safety and predictability of femtosecond laser-assisted cataract surgery (FLACS) in eyes with shallow anterior chamber (AC). METHODS: This is a prospective consecutive clinical study. All eyes presented an anterior chamber depth (ACD) ≤ 2.1 mm and were submitted to FLACS with monofocal intraocular lens (mIOL) or trifocal intraocular lens (tIOL) implantation. Uncorrected distance visual acuity (VA) and corrected distance VA values were used to assess efficacy and safety of the surgery. Refraction, intraocular pressure (IOP), endothelial cell density (ECD) and ACD were evaluated before and 6 months post-surgery. RESULTS: Phacoemulsification was carried out successfully in all eyes, without intra- or postoperative complications. Efficacy and safety indexes were 0.96 and 1.26 for the mIOL group, and 0.87 and 1.01 for the tIOL group, respectively. The mean postoperative spherical equivalent was - 0.06 ± 0.28D and - 0.14 ± 0.38D for the mIOL and tIOL groups, respectively. The ECD varied from 2470 ± 483 to 2009 ± 538 cells/mm2 (p < 0.05) and from 2443 ± 319 to 2245 ± 628 cells/mm2 (p = 0.06) for the mIOL and tIOL groups, respectively. IOP significantly decreased (p < 0.05) after the surgery from 14.34 to 12.85 mmHg for the mIOL group and from 14.37 to 11.91 mmHg for the tIOL group, with a general reduction of medical hypotensive treatment in both groups (85% of cases required ≤ number of medications). ACD changed significantly (p < 0.05) from 1.96 ± 0.15 mm to 3.75 ± 0.30 mm after the surgery in the mIOL group and from 1.94 ± 0.15 mm to 3.23 ± 0.21 mm for the tIOL group. CONCLUSION: FLACS with implantation of either mIOL or tIOL may provide good efficacy, safety and predictability in eyes with shallow AC.

Visual Function after Implantation of a Presbyopia-Correcting Trifocal Intraocular Lens.

PURPOSE: To evaluate distance, intermediate, and near visual performance in patients implanted with a trifocal aspheric presbyopia-correcting intraocular lens (IOL). METHODS: Forty patients were bilaterally implanted with the AcrySofIQ PanOptix IOL after femtosecond laser-assisted lens surgery. Binocular best corrected distance visual acuity (CDVA) (4 m), best distance-corrected near visual acuity (DCNVA) (40 and 30 cm), best corrected distance intermediate visual acuity (DCIVA) (70, 60, and 50 cm), binocular distance contrast sensitivity under photopic conditions (85 cd/m2), and defocus curves were evaluated at 6-months. RESULTS: Six months postoperatively, the mean binocular Snellen decimal CDVA and DCNVA were 0.94 ± 0.10 (ranging from 0.70 to 1.25) and 0.85 ± 0.13 (ranging from 0.63 to 1.00), respectively. At a distance, all patients showed a cumulative binocular distance-corrected visual acuity of 0.8 or better, and about 80% (n = 31) of the patients had a value of 1.0 (20/20). At near and intermediate distances, all patients showed a cumulative distance-corrected visual acuity of 0.5 (20/40) or better at 30, 40, 50, 60, and 70 cm. Specifically, 50 cm showed the highest percentage of patients with larger values of visual acuity (60% [n = 26] with 20/20). Defocus curve showed a wide range of useful vision with two peaks of best visual acuity at distance and at 50 cm, and the binocular distance contrast sensitivity was within normal limits. CONCLUSIONS: The outcomes of the present study show that the visual performance obtained with bilateral implantation of the trifocal aspheric AcrySofIQ PanOptix IOL is good at far, intermediate, and near distances.

Lensectomy after radial keratotomy: 1-year follow-up.

PURPOSE: To report visual and refractive results in radial keratotomy (RK) patients that underwent a cataract surgery with a monofocal intraocular lens (IOL) implantation with 1 year of follow-up. METHODS: Twenty-eight eyes of 15 patients with cataract and the previous RK were included. All eyes underwent phacoemulsification and monofocal IOL implantation. IOL power calculation was done using the Double-K formula of Aramberri. The preoperative versus postoperative corrected distance visual acuity (CDVA) and the uncorrected distance visual acuity (UDVA) values were used to assess the efficacy and safety of the surgery; meanwhile, the achieved versus the expected refractive outcomes postoperatively were used to assess the predictability. RESULTS: Phacoemulsification and IOL implantation was performed successfully in all eyes, and no intra- and postoperative problems occurred. The mean logMAR UDVA significantly improved from 0.7 ± 0.3 to 0.4 ± 0.2 at 6 months, and 0.3 ± 0.2 at 12 months postoperatively. By the end of the follow-up period, about 60% of the eyes achieved 20/25 or better CDVA, 25% of the eyes gained three or more lines of visual acuity, and two eyes had lost one or more lines of visual acuity. The mean spherical equivalent improved from - 1 ± 6.00 to - 0.75 ± 1.1 D by the end of the follow-up, and about 60% of the eyes were within ± 1 D at 12 months after the surgery. No intra- and postoperative problems occurred. CONCLUSIONS: Pseudophakic monofocal IOL implantation offers good visual acuity recovery and acceptable refractive correction in RK patients after 1-year follow-up.

In vitro optical quality of monofocal aspheric toric intraocular lenses: effect of cylindrical power.

PURPOSE: To assess the in vitro optical quality of monofocal aspheric toric intraocular lenses (IOLs) as a function of the cylindrical power. METHODS: The in vitro optical quality of the AcrySof IQ Toric IOLs SN6AT2, SN6AT3, SN6AT4, SN6AT5 and SN6AT6 (Alcon Laboratories Inc., Forth Worth, TX, USA) was assessed with an instrument conceived for measuring Zernike's coefficients at 3.0- and 5.0-mm apertures. As a reference, the aspheric monofocal lens AcrySof IQ Aspheric SN60WF (Alcon Laboratories Inc., Forth Worth, TX, USA) was also measured. The area of visibility and cut-off frequency were used to describe the modulation transfer function (MTF) of each lens; meanwhile, the light in the bucket and the diameter of a circular area centred on the point-spread function (PSF) peak that captures 50% of the light energy were used to describe the PSF of each lens. Finally, an image simulation was computed from the Zernike values with reference purposes. RESULTS: Small differences were found on the metrics used for describing the MTF and PSF of the lenses at both tested apertures, but these were not statistically significant (p > 0.05). Furthermore, the image simulation showed that these differences would not have clinical relevance at all. CONCLUSIONS: The optical performance of the AcrySof IQ toric IOLs in terms of MTF and PSF is good and seems to be independent of the cylindrical power and similar to a non-toric aspheric lens.

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.

Subjective outcomes after bilateral implantation of an apodized diffractive +3.0 D multifocal toric IOL in a prospective clinical study.

PURPOSE: To assess subjective outcomes after bilateral implantation of an aspheric apodized diffractive +3.0 diopter (D) multifocal toric intraocular lens (IOL). METHODS: This was a prospective, single-arm, 6-month study conducted at five study sites in Europe and South America. Forty-nine patients requiring bilateral cataract extraction or refractive lens exchange and IOL implantation in both eyes with preoperative regular corneal astigmatism of 0.75 D or greater and 2.5 D or less received bilateral AcrySof ReSTOR +3.0 D toric IOLs (Models SND1T3, SND1T4, or SND1T5; Alcon Laboratories, Inc., Fort Worth, TX). Subjective questionnaires were administered preoperatively and 6 months postoperatively. RESULTS: Patient subjective experience with visual tasks at all distances improved from the preoperative visit to the 6-month visit. At the 6-month visit, 90% (36 of 40) of respondents reported complete freedom from corrective wear compared with 14% (6 of 43) pre-operatively. On a scale of 0 (worst) to 10 (best), the mean score that patients rated their uncorrected vision was 7.9 ± 1.9 at 6 months (n = 37) compared with 3.6 ± 2.0 at the preoperative visit (n = 38). CONCLUSIONS: Six months following bilateral implantation of the AcrySof ReSTOR +3.0 D toric IOL revealed improved subjective experience, increased spectacle freedom, and higher satisfaction when compared with the preoperative baseline.

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.