Customized Toric Intraocular Lens Implantation in Eyes with Cataract and Corneal Astigmatism after Deep Anterior Lamellar Keratoplasty: A Prospective Study

Management of post-keratoplasty ametropia

Even after a successful corneal transplant, patients experience severe refractive errors, impeding their rehabilitation and satisfaction. Refractive errors can be caused by recipient pathology and corneal thickness, as well as intraoperative factors such as donor-host discrepancy, recipient's eccentric trephination, vitreous length, wound apposition, technique of suturing, and suture material. Also, wound healing and the interim between keratoplasty and suture removal contribute to astigmatism. Lamellar keratoplasty outperforms penetrating keratoplasty in terms of endothelial cell loss and endothelial graft rejection, yet the risk of developing refractive errors is comparable. Nonsurgical interventions such as spectacles and lenses fail to provide desirable vision in cases with high astigmatism and corneal irregularity. When these limitations are encountered, surgical interventions including incisional keratotomy, wedge resection, laser refractive surgeries, intracorneal segments, and intraocular lens implantation are employed. However, occasionally, none of these approaches deliver the desired effects, leading to the need for a repeat keratoplasty.

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.

Outcomes of cataract surgery with toric intraocular lens implantation after keratoplasty

PURPOSE

To evaluate the efficacy and predictability of cataract extraction with toric intraocular lens (IOL) implantation after deep anterior lamellar keratoplasty (DALK) or mushroom penetrating keratoplasty (PK).

SETTING

Villa Igea Hospital, Forlì, Italy.

DESIGN

Prospective case series.

METHODS

Toric IOL implantation was offered to patients with cataract, corneal astigmatism >1.5 diopters (D) and regular central corneal topography after complete suture removal. Phacoemulsification was performed through a 2.4 mm scleral tunnel and an enVista monofocal toric MX60T or Eyecryl monofocal toric IOL was inserted in the capsular bag. Main outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, total prediction error, and IOL misalignment.

RESULTS

37 consecutive patients who had previously undergone either DALK (n = 27, 73%) or 2-piece mushroom PK (n = 10, 27%) were included. All patients completed the 6-month follow-up. The mean toric IOL power was 5.3 ± 1.1 D. Both UDVA and CDVA significantly improved (from 1.02 ± 0.27 to 0.46 ± 0.31 logMAR and from 0.65 ± 0.27 to 0.11 ± 0.12 logMAR, respectively; P < .001). 20 eyes (54%) reached UDVA ≥20/40, whereas 35 eyes (95%) reached a CDVA ≥20/40. Final refractive astigmatism was 0.93 ± 0.87 D, with 35 eyes (95%) within 2 D. Prediction error was ≤1 D in 18 eyes (49%). Absolute IOL misalignment was 3.3 ± 3.5 degrees.

CONCLUSIONS

Toric IOL implantation in postkeratoplasty eyes allowed reduction of refractive astigmatism to predictably low levels with concomitant improved visual outcomes.

A novel blunt dissection technique to treat modified deep anterior lamellar keratoplasty (DALK)-associated high astigmatism

OBJECTIVES

To describe a new surgical technique to correct a high astigmatism following modified deep anterior lamellar keratoplasty (DALK) and to evaluate the associated clinical outcomes.

METHODS

Retrospective interventional case series included eyes with high astigmatism following modified DALK performed between July 2012 and June 2016. The prevalence of keratometric astigmatism (KA) higher than 4.5 diopters (D) was evaluated after complete suture removal. Surgical correction was obtained by opening the surgical wound at the steeper meridian and carrying out a blunt dissection at the graft-host surface of contact under keratoscopic control. KA, Refractive astigmatism (RA), and best spectacle-corrected visual acuity (BSCVA) were measured preoperatively and at 1, 12, and 24 months postoperatively. Vector analysis of 1 year change in KA was performed.

RESULTS

High astigmatism was found in 47 of 511 eyes (9.2%). KA (mean ± standard deviation [SD]) decreased from 7.67 ± 2.78 to 3.10 ± 1.37 D at 1 month after astigmatic correction (p < 0.001) with no subsequent significant change. Vector analysis of 1 year change in KA: surgically induced astigmatism was 5.30 ± 3.29 D and mean absolute angle of error was 6.97 ± 4.25°. BSCVA improved from 0.21 ± 0.20 logMAR preoperatively to 0.11 ± 0.13 logMAR (p < 0.001); RA decreased from 6.32 ± 2.56 to 2.61 ± 1.05 D (p < 0.001). No intra- or post-operative complications occurred.

CONCLUSIONS

High astigmatism is present in <10% of cases after modified DALK and can be effectively managed by means of blunt relaxing dissection at the graft-host junction.

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.