Management of Anterior Stromal Necrosis After Polymethylmethacrylate ICRS: Explantation Versus Exchange With Corneal Allogenic Intrastromal Ring Segments

PURPOSE: To evaluate management of keratoconic eyes with anterior stromal necrosis overlying the intracorneal ring seg-ment (ICRS), by either ICRS explantation alone or exchange with corneal allogenic intrastromal ring segments (CAIRS). METHODS: Among 643 Intacs SK (Additional Technology, Inc) inserted at one institutional center, 16 eyes (15 patients) with overlying spontaneous anterior stromal necrosis were identi-fied. Data included size of stromal defect and refractive and topographical findings before ICRS insertion, before anterior stromal necrosis, and 6 months after intervention. RESULTS: The 10-year incidence of anterior stromal necrosis after femtosecond laser-assisted ICRS insertion was 5.5%. Eight eyes underwent ICRS removal only and 8 eyes had ICRS exchanged with CAIRS. In the first group, CDVA worsened from 0.14 before melt to 0.28 logMAR after removal (P = .10), simulated keratometry (SimK) and maximum axial keratom-etry (Kmax) increased from 44.73 to 46.34 diopters (D) (P = .14) and from 49.23 to 52.26 D (P = .14), respectively, and comaworsened from 0.87 to 1.52 D (P = .02). In the CAIRS group, CDVA of 0.16 before melt improved to 0.11 logMAR postopera-tively (P > .99), and topographic indices stabilized with SimK, Kmax, and coma mildly altering from 45.31 to 45.44 D (P > .99), from 49.25 to 49.64 D (P > .99) and from 0.87 to 0.81 D (P > .99), respectively. Whether the ICRS were explanted or exchanged, the visual and topographic mean values were bet -ter than those reported before ICRS implantation, whereas higher order aberrations in eyes without CAIRS regressed to levels before ICRS insertion. At the site of melt, thinnest re-sidual stromal thickness averaged 327 mu m with ICRS removal and 490 mu m with CAIRS. Eyes with larger melt areas resulted in less optimal results with CAIRS implantation. CONCLUSIONS: Early experience in the management of ante-rior stromal necrosis by exchange of polymethylmethacrylate ICRS with CAIRS seems to avoid stromal thinning and confer better visual and topographic results, which were more pro-nounced with thicker segments. The benefit of CAIRS in large stromal melts needs to be investigated.

Automated summary

Early experience suggests that the exchange of polymethylmethacrylate ICRS with CAIRS in the management of anterior stromal necrosis can prevent stromal thinning and provide better visual and topographic results, particularly with thicker segments. Further investigation is needed to assess the benefits of CAIRS in cases of large stromal melts.