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. 2023 Mar 24;87(4):e2022-0128.
doi: 10.5935/0004-2749.2022-0128. Online ahead of print.

Corneal reshaping: an experiment with a type I collagen-based vitrigel for remodeling porcine corneas

Maria Carolina Marquezan  1   2 , Denise de Freitas  2 , Shoumyo Majumdar  1   3 , Xiaokun Wang  1   3 , Jennifer Elisseeff  1   3 , David L Guyton  1 , Kraig Scot Bower  1 , Zachary P Skurski  1 , Maria Regina Chalita  4 , Rubens Belfort Jr  2 , Albert S Jun  1
Affiliations

Corneal reshaping: an experiment with a type I collagen-based vitrigel for remodeling porcine corneas

Maria Carolina Marquezan et al. Arq Bras Oftalmol. .

Abstract
in English, Portuguese

Purpose: This study aimed to report an experiment designed to determine anatomical changes in porcine corneas following placement of a novel polymer implant into the cornea.

Methods: An ex vivo porcine eye model was used. A novel type I collagen-based vitrigel implant (6 mm in diameter) was shaped with an excimer laser on the posterior surface to create three planoconcave shapes. Implants were inserted into a manually dissected stromal pocket at a depth of approximately 200 μm. Three treatment groups were defined: group A (n=3), maximal ablation depth 70 μm; Group B (n=3), maximal ablation depth 64 μm; and group C (n=3), maximal ablation depth 104 μm, with a central hole. A control group (D, n=3) was included, in which a stromal pocket was created but biomaterial was not inserted. Eyes were evaluated by optical coherence tomography (OCT) and corneal tomography.

Results: Corneal tomography showed a trend for a decreased mean keratometry in all four groups. Optical coherence tomography showed corneas with implants placed within the anterior stroma and visible flattening, whereas the corneas in the control group did not qualitatively change shape.

Conclusions: The novel planoconcave biomaterial implant described herein could reshape the cornea in an ex vivo model, resulting in the flattening of the cornea. Further studies are needed using in vivo animal models to confirm such findings.

Objetivo: Relatar um experimento projetado para determinar alterações anatômicas em córneas porcinas após a colocação de um novo implante de polímero na córnea.

Métodos: Foi utilizado olho de porco ex vivo. Um novo agente modelador biocompatível, de colágeno tipo 1, com 6mm de diâmetro foi moldado com excimer laser em sua face posterior, para criar três formatos planocôncavos. Os implantes foram inseridos dentro de um bolsão, dissecado manualmente, a 200 micrômetros (µm). Foram definidos três grupos de tratamento: grupo A (n=3), teve a profundidade máxima de ablação de 70 µm; o grupo B (n=3), profundidade máxima de ablação de 64 µm; e o grupo C (n=3), profundidade máxima de ablação de 104 µm, com buraco central. O grupo controle, D (n=3), foi incluído, com a criação do bolsão estromal, porém sem inserir o material. A avaliação desses olhos foi realizada por tomografia de coerência óptica (OCT) e por tomografia corneana.

Resultados: A tomografia corneana mostrou uma tendência para diminuição da ceratometria média em todos os 4 grupos. A tomografia de coerência óptica mostrou córneas com implantes localizados no estroma anterior e aplanamento visível, enquanto as córneas não mudaram qualitativamente o formato no grupo controle.

Conclusões: O novo implante de biomaterial planocôncavo descrito aqui foi capaz de remodelar a córnea em modelo de animal ex vivo, resultando no aplanamento corneano. Novos estudos são necessários usando modelos animais in vivo para confirmar tais achados.

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Figures

Figure 1
Figure 1
Visante® anterior-segment OCT of the implant from group A, before (left) and after (right) excimer laser treatment.
Figure 2
Figure 2
A, B, and C. Representative Visante® OCT images from groups A, B, and C, respectively, before (left) and after (middle) insertion of cornea, showing corneal flattening and gross appearance of the post-insertion corneas (right).
Figure 3
Figure 3
Representative Pentacam® images from a group A specimen before (left) and after (right) corneal insertion. A flatter shape was seen after biomaterial insertion.
See this image and copyright information in PMC

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