Comparison of Bowman-Stromal Inlay With Contralateral Eye Corneal Cross-linking Performed for Progressive Keratoconus

Abstract

PURPOSE:To report the outcomes of Bowman-Stromal Inlay (BSI) and corneal cross-linking (CXL) performed in the right and left eyes, respectively, of a pediatric patient with bilateral progressive ectasia. METHODS:A 10-year-old boy underwent CXL in his left eye for stage 2 keratoconus and BSI in his right eye for stage 4 keratoconus. Serial refractive and tomographic outcomes were recorded and analyzed. RESULTS:There was no progression of ectasia in either eye through the final follow-up visit at 28 months postoperatively. Compared to the left eye that underwent CXL, the right eye that underwent BSI showed a reduction in tomographic keratometry, astigmatism, superior-inferior asymmetry, and increased pachymetry. There was no perioperative complication in either eye.CONCLUSIONS: CXL and BSI achieved similar outcomes over the course of 2 years in arresting the progression of ectasia. BSI may have the additional benefit of increased postoperative pachymetry.

Customized Bowman-Stromal Inlay: An Attempt to Change the Topography of the Keratoconus Cornea

“…This was a positive development as we did not see significant improvement in keratometry and visual acuity with the earlier reported technique (BSI with parallel surfaces, convex-convex). 5 The expected final central pachymetry in the present case was 517 (calculated as 397 mm of thinnest pachymetry at presentation + 190 mm of inlay thickness 2 70 mm of excimer laser ablation of the stromal bed of the inlay). The central pachymetry as measured on tomography was 461 mm, whereas same on optical coherence tomography (CIRRUS HD-OCT, Carl Zeiss Meditech) was 504 mm.…”

“…This was a positive development as we did not see significant improvement in keratometry and visual acuity with the earlier reported technique (BSI with parallel surfaces, convex–convex). 5…”

“…4 We have also reported a case where BSI efficacy was found to be equal to that of CXL performed in the contralateral eye of a child with progressive keratoconus. 5 Similarly, there are published reports of transplant of the inlay consisting of mid-stroma harvested from refractive surgery patients using the small incision lenticule extraction technique and that of BL alone harvested from the donor cornea into mid-stroma of the keratoconus cornea. Collagen crosslinking was not performed in these intrastromal augmentation surgeries and was still found to be effective in causing stabilization of ectasia.…”

“…1,2 In such scenarios, other modalities such as a transplant of an isolated Bowman's layer (BL) and corneal stromal lenticule harvested from the small incision lenticule extraction refractive procedure or eye bank donor corneal tissue have been described apart from more invasive procedures such as penetrating keratoplasty and deep anterior lamellar keratoplasty. [3][4][5][6][7][8] We have recently published our work on combined BL transplant and stromal augmentation [Bowman-stromal inlay (BSI)], which was found to prevent progression in keratoconus. The surgery is technically simple in which an inlay graft having parallel surfaces was prepared from the eye bank cornea using a femtosecond laser (Wave-Light Allegretto FS 200) and transplanted in the anterior stromal pocket (created by the same laser) of the host keratoconus cornea.…”

“…The surgery is technically simple in which an inlay graft having parallel surfaces was prepared from the eye bank cornea using a femtosecond laser (Wave-Light Allegretto FS 200) and transplanted in the anterior stromal pocket (created by the same laser) of the host keratoconus cornea. 4,5 To further achieve corneal flattening along with stabilization of corneal topography in keratoconus eyes, we customized the inlay into a negative meniscus shape by ablating the stromal side with an excimer laser before placing in the host cornea. In the present manuscript, we report our experience with the first case of this modified technique that we called customized Bowman-stromal inlay (cBSI).…”