Phakic intraocular Lens implantation in keratoconus patients

BACKGROUND

Both the anterior chamber and posterior chamber phakic intraocular lenses (pIOLs) implantation are acceptable refractive surgical approaches in keratoconus patients with high anisometropia, contact lens intolerance, or who prefer spectacle and contact lens independent. They are beneficial for correcting anisometropia in stable keratoconus cases or following corneal procedures such as intrastromal corneal ring segments (ICRS), collagen cross-linking (CXL), and keratoplasty. They are suitable for eyes without advanced keratoconus with acceptable best-corrected distance visual acuity (BCDVA) or without highly irregular astigmatism, high comma, and higher-order aberrations (HOAs). Combined procedures for irregular astigmatism reduction and corneal regularization with either ICRS or topography/wavefront-guided transepithelial PRK (with or without CXL) can be associated in advance with pIOLs implantation to improve BCDVA in these cases.

AIM

To study and report the evidence regarding the safety and efficacy of pIOLs for KC patients' visual and refractive rehabilitation, we have analyzed the scientific evidence published within the last 10 years (from 2012 onwards).

RESULTS

No randomized controlled trials but only eleven retrospective case series and two prospective case series were identified. Satisfactory visual rehabilitation was achieved regarding uncorrected and corrected distance visual acuity (CDVA) and predictability of the refractive correction. Both types of pIOL (iris claw and posterior chamber pIOLs) offer very good results in terms of safety and efficacy with indexes close to or even exceeding 1.

CONCLUSION

pIOLs implantation is a valid refractive therapeutic approach for correcting stable keratoconus with moderate-to-high refractive errors, especially anisometropia associated with regular or mildly irregular astigmatism, and good CDVA.

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.

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.

Correction of high astigmatism with toric intraocular lens in eyes with corneal transplant

OBJECTIVES

To evaluate the results of toric intraocular lens (IOL) implantation during cataract surgery in eyes with high regular astigmatism associated with prior penetrating keratoplasty (PK).

METHODS

A retrospective data analysis of patients with prior PK, who underwent uncomplicated cataract surgery with hydrophobic toric single piece IOL (EyeCryl Toric®, Biotech Vision Care, Luzern, Switzerland).

RESULTS

A total of 18 eyes of 18 patients were included in the study. The mean age was 53.4 ± 12.4 (25-70) years. The mean follow-up period was 15.5 (4-24) months. The mean best corrected visual acuity (BCVA) significantly increased from 1.36 ± 1.0 logMAR to 0.31 ± 0.17 logMAR (p < .001) pre- and post-operative 4 weeks, respectively. There was no significant change in mean BCVA during follow-up; mean BCVA was 0.32 ± 0.17 logMAR at the last visit. The mean pre-operative topographic astigmatism was 6.52 ± 1.80 diopters (D). The mean manifest refraction astigmatism was decreased from 6.55 ± 1.62 D to 2.80 ± 1.43 D (p˂0.001). The mean Surgically induced astigmatism (SIA) was 3.74 ± 0.77 D according to vector analysis. There was no patient with graft rejection or failure, the mean endothelial cell loss rate was 12.75 ± 3.76% (7-17%). There was no patient requiring IOL reposition.

CONCLUSIONS

Toric IOL implantation during cataract surgery provides an option to correct astigmatism in post-PK eyes with high regular astigmatism. When appropriate patients are selected it is a safe method to achieve significant improvements in visual acuity and astigmatism.

Toric intraocular lens for astigmatism correction following keratoplasty in phakic and pseudophakic eyes

ABSTRACT

Residual astigmatism and anisometropia significantly impact patients' vision and quality of life even in clear grafts after corneal transplant. We reviewed and summarized the role of toric intraocular lens (IOL) in phakic and pseudophakic eyes after penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) in correcting residual astigmatism. We included 342 eyes from 20 studies with iris-clipped toric IOL, ciliary sulcus toric implantable collamer lens, piggyback sulcus toric IOL, or posterior chamber toric IOL implantations for phakic, pseudophakic, or eyes undergoing cataract surgery after keratoplasty. Visual, refractive, and predictability outcomes were encouraging. Secondary re-alignment rate and complications were low. Endothelial cell loss secondary to phakic toric IOL might be a concern over the long-term, particularly in iris-clipped IOL in PKP eyes. Toric IOL represent a viable option in the treatment of residual astigmatism in post-keratoplasty eyes, resulting in improved visual acuity and reduced anisometropia.

Analysis of the Effect of Intraocular Lens Implantation on Retinal Nerve and Postoperative Nursing Outcome Based on Ultrasound Imaging

Traumatic cataract is a common complication of ocular contusion. Caused by various forms of trauma, the course and prognosis of traumatic cataract are also different. Intraocular lens (IOL) implantation is the most effective treatment at the present time and can provide good visual quality and near, medium, and far vision. In this study, an adaptive medical ultrasound image denoising algorithm was constructed based on the biological vision mechanism and was applied to observe IOL implantation and postoperative care of 30 patients with traumatic cataract. Results showed that eyesight could be restored to the original healthy state after IOL implantation, and eyesight was close to normal 3 months after surgery. The corresponding noise pixel block of the noise reduction algorithm was obviously the lowest. A total of 30 patients (9 patients with contusion, 13 patients with intraocular foreign body, and 8 patients with perforation) were treated with aspheric and multifocal IOL to achieve the expected outcome. The noise reduction algorithm constructed in this study effectively reduced the speckle noise of ultrasound images, improved the clarity of ultrasound images, and achieved the effective observation of medical nursing outcome after traumatic cataract IOL implantation. After IOL implantation, the retinal nerves of patients with traumatic cataract were affected to different degrees.

Safety and visual outcomes following Iris-claw phakic intraocular lens bilensectomy

PURPOSE

To evaluate the visual outcomes, safety, efficacy, and causes of bilensectomy for iris fixated phakic intraocular lenses (pIOLs).

METHODS

This was a two center consecutive retrospective study that included 43 eyes that underwent iris-claw pIOL bilensectomy. Patients with follow up less than 4 months were excluded from the study. Uncorrected, corrected visual acuity (UCVA, CDVA), refractive outcomes, efficacy, safety (number of eyes in which the postoperative CDVA was worse than the preoperative CDVA), endothelial cell density (ECD), causes of bilensectomy, the time between the implantation of the pIOL and bilensectomy, intra and postoperative complications were analyzed.

RESULTS

There was a statistically significant improvement in UCVA and CDVA after surgery (p = 0.001). The efficacy index was 0.7, four eyes had a postoperative CDVA worse than the preoperative CDVA. The mean spherical equivalent 1 year after bilensectomy was -0.78 ± 1.70 D. There was a statistically significant endothelial cell loss after iris claw lens bilensectomy (p = .003). Cataract development and endothelial cell loss were the only reasons for bilensectomy. The mean time between pIOL implantation and bilensectomy was 12.2 ± 5.5 years. One patient had corneal edema 8 months after surgery and one had a retinal detachment 11 months after surgery.

CONCLUSION

Bilensectomy was successful in improving UCVA and CDVA with an acceptable refractive outcome. Significant loss of ECD was found after surgery. The results recommend a larger ACD as selection criteria when choosing to implant an Artisan lens, and a close postoperative monitoring of the endothelial cell count.

Evaluation of axis alignment and refractive results of toric phakic IOL using image-guided system

AIM

To evaluate accuracy of axis alignment and refractive results of toric phakic intraocular lens (IOL) implantation using a digital imaging system.

METHODS

This retrospective study investigated toric implantable collamer lens (ICL) implantation in 30 eyes of 21 patients with myopic astigmatism more than 2.0 D guided with digital imaging system. Data were collected during the first week after phakic IOL implantation.

RESULTS

Thirty eyes of 21 patients were included in our study. Patients includes 9 males and 12 females. The mean age of the patients was 26.5±7.1 (range 21-44)y. The mean preoperative manifest astigmatism was 3.2±1.7 (range from 2.25 to 4.75) D. The mean postoperative uncorrected distance visual acuity (UCDVA) were 0.07±0.07 (range from 0.1 to 0.0) logMAR. The mean postoperative residual refractive cylinder was 0.25±0.29 (range 0-0.75) D. Eyes with postoperative residual refractive cylinder of 0.5 D or less represented 80% (24 eyes). The mean postoperative toric IOL misalignment measured by the OPD scan III was 1.9°±1.45° (range from 0 to 5°).

CONCLUSION

Image guided system allows accurate alignment of toric ICL. This is associated with good postoperative visual acuity and low residual refractive astigmatism which correlates with the precision of toric phakic IOL alignment.

Phakic Intraocular Lens Implantation After Deep Anterior Lamellar Keratoplasty: Retrospective Case Series Analysis With Long-Term Follow-Up

Purpose

To report outcomes of phakic intraocular lens (IOL) implantation after deep anterior lamellar keratoplasty (DALK) to correct high ametropia.

Setting

Centro Hospitalar Universitário do Porto, Portugal.

Methods

Retrospective case series with 11 eyes submitted to phakic IOL implantation after DALK. Main outcomes measured were uncorrected and corrected distance visual acuity (UDVA and CDVA), refractive error components, tomographic parameters and endothelial cell density (ECD). The minimum follow-up was 3 years for all cases.

Results

Mean ECD loss was 8.7±6.7% at 1 year, 13.1±8.6% at 3 years (n=11; p=0.016, p=0.007, respectively) and 14.0±20.4% at 5 years (n=5, p=0.212). Mean logMAR UDVA increased from 1.27±0.90logMAR preoperatively to 0.16±0.15logMAR postoperatively (p≤0.001) and no statistically significant differences were registered during follow-up. All patients gained at least 5 lines of UDVA. 54.5% of the eyes gained 1 line in CDVA postoperative and only one eye lost one CDVA line through follow-up. Efficacy and safety indexes at 1 and 3 years were 1.01–0.97 and 1.24–1.21, respectively. Mean spherical equivalent was reduced from −7.84±4.63 D preoperatively to −1.05±1.07 D postoperatively (p=0.001). Mean percentage of reduction in refractive cylinder and spherical error was 83.8±15.8% and 73.1±31.5%, respectively, p≤0.001 for both. In one eye there was a significantly gradual ECD loss over 5 years follow-up and the patient will be submitted to IOL explant.

Conclusion

Phakic IOLs were effective for correction high ametropia after DALK, showing high efficacy and safety indexes with stability over time. However, it was registered a continuing endothelial cell loss postoperatively, which assumed to be higher than those reported in eyes without DALK.

Stepwise Combination of Femtosecond Astigmatic Keratotomy With Phacoemulsification and Toric Intraocular Lens Implantation in Treatment of Very High Postkeratoplasty Astigmatism

PURPOSE

To report the outcomes of stepwise combined femtosecond astigmatic keratotomy (FSAK) and phacoemulsification with toric intraocular lens (IOL) implantation in the treatment of very high astigmatism after either penetrating keratoplasty or deep anterior lamellar keratoplasty.

METHODS

This is a retrospective, interventional case series including 8 eyes of 6 patients with very high astigmatism [≥8.00 diopter (D)] after either penetrating keratoplasty or deep anterior lamellar keratoplasty who underwent FSAK, followed by phacoemulsification and toric IOL implantation. Outcome measures were corneal and manifest astigmatism and uncorrected and best spectacle-corrected visual acuity (UCVA, BSCVA).

RESULTS

The average age was 58.9 ± 5.1 years. The average follow-up time was 40.9 ± 43.8 months. Outcome measure changes after both FSAK and toric IOL implantation were: corneal astigmatism improved from 13.56 ± 4.81 D to 4.48 ± 2.83 D (P < 0.001), manifest astigmatism improved from 9.15 ± 3.86 to 1.46 ± 0.88 D (P = 0.011), UCVA improved from 1.69 ± 0.45 LogMAR (Snellen equivalent ∼20/980) to 0.23 ± 0.11 LogMAR (Snellen equivalent ∼20/33, P < 0.001), and BSCVA improved from 1.01 ± 0.71 LogMAR (Snellen equivalent ∼20/200) to 0.19 ± 0.11 LogMAR (Snellen equivalent ∼20/30, P = 0.015). BSCVA and UCVA at the last follow-up were 20/40 or better in all patients. All procedures were uneventful. Two eyes underwent photorefractive keratectomy after FSAK to regularize and further reduce astigmatism before toric IOL implantation. One patient underwent temporary compression suturing because of FSAK overcorrection.

CONCLUSIONS

Combined stepwise use of FSAK and phacoemulsification with toric IOL implantation was an effective and apparently safe approach in patients with very high postkeratoplasty astigmatism. Additional treatment using photorefractive keratectomy may be beneficial in some cases.

Updates on Managements for Keratoconus

Purpose

Keratoconus is a progressive disease of the cornea which can lead to blindness as irregular astigmatism increases. Currently, a variety of methods are available for the treatment of keratoconus, and in certain cases, it may be difficult to choose the most appropriate option. This article reviews available treatment modalities for keratoconus to provide the practitioner with practical and useful information for selecting the most suitable option for each individual patient.

Methods

To review treatment methods for different stages of keratoconus, PubMed (United States National Library of Medicine) and Scopus (Elsevier BV) databases were searched using the keywords “keratoconus”, “contact lens”, “cross-linking”, “Intacs”, “keratoplasty”, “gene therapy”, and “irregular astigmatism”, and related articles were reviewed based on disease assessment parameters and treatment methods.

Results

Various methods are available for the treatment of keratoconus: eyeglasses and contact lenses in the early stages, cross-linking for stabilizing disease progression, intrastromal corneal ring segments (ICRS) for reducing refractive errors or flattening the cornea, and penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK), conductive keratoplasty, gene therapy and more recently, bowman layer transplantation (BL transplantation) in advanced stages of the disease. To achieve optimum results, it is essential to choose the best option for each individual patient.

Conclusions

A commonality of the reviewed papers was the advancement of novel diagnostic and treatment methods in ophthalmology, which can delay the need for corneal grafting. A better understanding of keratoconus treatment options can help enhance visual rehabilitation and prevent blindness in keratoconus patients.