Topography-Guided Photorefractive Keratectomy in the Treatment of Corneal Scarring

Corneal scar after ulcer in a young patient demanding visual restoration in a timely fashion treated with PTK + topo-guided PRK

A 23-year-old woman was referred for low visual acuity in the left eye after a corneal ulcer associated with contact lens use 2 years previously. The patient had a history of contact lens use, reported use of antibiotic eye drops with improvement of infection, and subsequent scarring. There were no comorbidities. The manifest refraction was -3.25 -2.25 × 180 (20/20) in the right eye and was -2.00 esf -2.00 × 165 (20/80) in the left eye. The patient demands a solution in a reasonable time because of the need for functional vision and possible restoration of her binocular functions. The slitlamp examination revealed a corneal scar partially affecting the visual axis (Figure 1JOURNAL/jcrs/04.03/02158034-202412000-00016/figure1/v/2024-12-12T192825Z/r/image-tiff). Corneal topography revealed an irregular pattern and spectral-domain optical coherence tomography (OCT) examinations revealed scarring in the anterior stroma (Figures 2 and 3JOURNAL/jcrs/04.03/02158034-202412000-00016/figure2/v/2024-12-12T192825Z/r/image-tiffJOURNAL/jcrs/04.03/02158034-202412000-00016/figure3/v/2024-12-12T192825Z/r/image-tiff). Given the patient's refraction, corneal scar, and visual demands, would you perform photorefractive keratectomy (PRK) treatment to correct ametropia and partially remove the anterior stroma? Would you perform excimer laser treatment for therapeutic purposes guided by topography? Would you opt for a 2-stage treatment, regularizing the cornea with neutral phototherapeutic keratectomy (PTK) or PRK treatment guided by topography and then correcting the ametropia? Considering the OTC maps, would you perform a femtosecond laser-assisted anterior lamellar keratoplasty (FALK), deep anterior lamellar keratoplasty (DALK), or even penetrating keratoplasty? Would you consider any other surgical step to prevent delayed cornea healing-persistent epithelial defect?

Addressing corneal opacity after herpes zoster infection

A 15-year-old boy was referred for corneal opacity evaluation. The patient had a previous herpes zoster virus (HZV) infection-varicella-zoster virus (VZV)-with ocular manifestation 1 year ago. After the infection, he developed a central corneal scar and decreased corrected distance visual acuity (CDVA) in the right eye. The slitlamp examination showed the right eye with central corneal opacity (involving anterior stroma), lacuna area between the haze, fluorescein negative, and no vascularization near the scar (Figure 1JOURNAL/jcrs/04.03/02158034-202406000-00019/figure1/v/2024-07-10T174224Z/r/image-tiff). The patient had been treated with oral valacyclovir and topical corticosteroids without any improvement of visual acuity or changes in opacity within the 1-year follow-up. His CDVA was 20/200 (-4.50 -0.75 × 25) in the right eye and counting fingers (-4.00) in the left eye. Intraocular pressure was 12 mm Hg in both eyes. Fundoscopy was normal in the right eye, but he had a macular scar in the left eye (diagnosed when he was 7 years). The left eye had no cornea signs. The patient has no comorbidity or previous surgeries. Considering this case, a corneal central scar in a 15-year-old boy, legally single eye only, and assuming it is an opacity in the anterior stroma, would you consider surgery for this patient? If so, which would you choose: Would you consider an excimer laser treatment of his ametropia while partially removing his opacity, a phototherapeutic keratectomy (PTK), or a PTK followed by a topography-guided treatment, femtosecond laser-assisted anterior lamellar keratoplasty (FALK), or deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (depending on the scar depth)? Would you consider prophylactic acyclovir during and after surgery? Would you consider any other surgical step to prevent delayed corneal healing-persistent epithelial defect? Before the surgical approach, would you consider treating this patient with topical losartan (a transforming growth factor [TGF]-β signaling inhibitor)? Would you first perform the surgery (which one) and then start the medication? Furthermore, if so, how long would you treat this patient? Would you consider treatment with another medication?

[Combined transepithelial PTK and topography-guided PRK for treatment of trauma-related corneal scarring]

BACKGROUND

Corneal scars can severely impair visual performance and treatment can be challenging. The study aimed to evaluate a promising minimally invasive option in the treatment of corneal scars using transepithelial topography-guided ablation.

METHODS

This retrospective interventional study involved four eyes of four patients who developed corneal scarring and irregular surfaces due to trauma and were treated with topography-guided photorefractive keratectomy (TG-PRK) between 2017 and 2020. The ablation profile was calculated in all four cases using CRS-Master (Zeiss, Jena, Germany). The main outcome measures were uncorrected and best-corrected distance visual acuity, manifest refraction and corneal regularity by topographic images. The mean age was 34.75 ± 15.39 years and the follow-up time was 6 months for all patients.

RESULTS

In three cases full subjective refraction was corrected in one session and one patient had a refractive error of +0.5 D. Only corneal surface smoothing without additional refractive correction was performed in this case. All four patients showed improvement in uncorrected (2-3 Snellen lines) and corrected (3 Snellen lines) distance visual acuity. No complications occurred during or after the treatment and there was no reduction of visual acuity in any case.

CONCLUSION

The use of TG-PRK in patients with corneal scarring improves visual acuity in selected cases. In myopic patients most of the refractive error can also be corrected in a single session.

Optical Coherence Tomography-Guided Femtosecond LASIK in the Setting of Corneal Scarring

Purpose

To report the outcomes of femtosecond-assisted laser in situ keratomileusis (LASIK) in patients with previous corneal scarring using optical coherence tomography (OCT) imaging to determine flap depths.

Methods

The charts of 11 eyes of 9 patients with previous off-visual axis corneal scarring that underwent femtosecond LASIK using OCT guidance for flap depth determination were retrospectively reviewed at a single private practice institution. The baseline characteristics, intraoperative findings and postoperative outcomes were analyzed.

Results

All 11 eyes underwent femtosecond laser flap creation and LASIK without any significant intraoperative complications. Uncorrected visual acuity improved postoperatively (p<0.0001) and remained stable at 3 months follow-up. None of the subjects lost any lines of best spectacle corrected visual acuity or developed any flap complications during the postoperative period.

Conclusion

The OCT-guided femtosecond laser technique described in this report can provide a safe and effective method to deliver LASIK in the setting of previous corneal scarring. Future investigations are required to further validate the findings in this study.

Visual rehabilitation by using corneal wavefront-guided transepithelial photorefractive keratectomy for corneal opacities after epidemic keratoconjunctivitis

PURPOSE

To evaluate long-term visual and refractive outcomes of corneal wavefront-guided transepithelial photorefractive keratectomy (t-PRK) with mitomycin C for the treatment of corneal opacities secondary to adenoviral epidemic keratoconjunctivitis.

METHODS

Records of patients who underwent corneal wavefront-guided t-PRK with excimer laser from January 2012 to December 2018 were retrospectively reviewed. Preoperative and postoperative uncorrected visual acuity, best-spectacle corrected visual acuity, slit-lamp biomicroscopic examination findings, manifest refraction, and corneal aberrations and fundus examination findings were evaluated.

RESULTS

Twenty-two eyes of 22 patients comprising 12 male (55%) and 10 female (45%) were treated. The mean age was 34.5 ± 10.8 years (range 19-55). The mean follow-up time was 34.4 ± 17.50 months (range 13-61 months). There was a statistically significant improvement in UCVA and BSCVA (p < 0.001 and p = 0.02), and there was a significant decrease in total higher-order aberrations, spherical, coma and trefoil aberration at postoperative first year (p < 0.001 in each). In two eyes of two patients, minimal haze formation was observed after the procedure, and both eyes were treated with topical steroid. No recurrence was observed in subepithelial infiltrates in any patient during long-term follow-up.

CONCLUSION

In long-term clinical follow-up, corneal wavefront-guided t-PRK treatment is an effective and reliable treatment method for rehabilitation of visual impairment due to corneal scars following adenoviral infections, in properly selected patients.

[Excimer laser in keratoconus management]

Visual rehabilitation in keratoconus is a challenge, notably because of the significant irregular astigmatism and optical aberrations that it induces. Many surgical techniques have been developed in addition to, or in the case of failure of, spectacles and rigid gas permeable contact lenses: intracorneal ring segments, intraocular lenses, excimer laser and, as a last resort, keratoplasty. Excimer laser photoablates the cornea, allowing remodeling of its surface. There are various treatment modes (wavefront-optimized, wavefront-guided and topography-guided), allowing performance of a customized treatment if needed. Its use in keratoconus has been described since the 2000s, alone or in combination with other procedures. For example, the combination of photoablation and corneal cross linking, a technique that increases corneal rigidity and in so doing can slow or even stop the progression of keratoconus, proved its efficacy and safety in many studies, and various protocols have been described. A triple procedure, including intracorneal ring segments, excimer laser and cross linking, has also given some very promising results in progressive keratoconus, providing a significative improvement in visual acuity and topographic data. The combination of excimer laser and intraocular lenses remains a poorly explored lead that might provide some satisfactory results. The objective of this review is to summarize the recent data on excimer laser in keratoconus management.