Analysis of imaging biomarkers and retinal nerve fiber layer thickness in RPGR-associated retinitis pigmentosa.

PURPOSE: To investigate multimodal retinal imaging characteristics including the retinal nerve fiber layer (RNFL) thickness in patients with RPGR-associated retinitis pigmentosa (RP). METHODS: This cross-sectional case-control study included 17 consecutive patients (median age, 21 years) with RPGR-associated RP who underwent retinal imaging including optical coherence tomography (OCT), short-wavelength fundus autofluorescence (AF) imaging, and RNFL scans centered on the optic disc. RNFL thickness was manually segmented and compared to clinical and imaging parameters including the transfoveal ellipsoid zone (EZ) width, the horizontal diameter of the macular hyperautofluorescent ring. RNFL thickness was compared to 17 age- and sex-matched controls. RESULTS: In patients with RPGR-associated RP, the EZ width (R2 = 0.65), the central hyperautofluorescent ring on AF images (R2 = 0.72), and visual acuity (R2 = 0.68) were negatively correlated with age. In comparison to controls, a significantly (p < 0.0001) increased global RNFL thickness was identified in RPGR-associated RP, which was, however, less pronounced in progressed disease as indicated by the EZ width or the diameter of the central hyperautofluorescent ring. CONCLUSIONS: This study describes retinal characteristics in patients with RPGR-associated RP including a pronounced peripapillary RNFL thickness compared to healthy controls. These results contribute to the knowledge about imaging biomarkers in RP, which might be of interest for therapeutic approaches such as gene replacement therapies.

Wound Healing of Descemet Membrane After Penetrating Keratoplasty and Its Relevance for Descemet Membrane Endothelial Keratoplasty Surgeons.

ABSTRACT: Compared with penetrating keratoplasty (PK), Descemet membrane endothelial keratoplasty (DMEK) is characterized as lower risk for complications such as immunological graft reaction and faster and better postoperative visual recovery. In patients with endothelial graft failure after PK, DMEK can be used to regenerate PK graft transparency. The surgical technique for DMEK in this specific situation is still under debate, particularly regarding stripping of Descemet membrane (DM) from the failed PK and diameter of the DMEK graft. Here we report a case of a 75-year-old female patient with a failed graft 16 years after PK for Fuchs endothelial dystrophy, who underwent uneventful DMEK surgery. Stripping of DM in this particular case was performed outside the failed PK and demonstrated a biomechanically stable junction between the PK donor and the host DM. Histopathologic analysis of the excised DM showed continuous extracellular matrix connecting the host and donor DM, indicating primary intention wound healing after PK at this tissue level. This case demonstrates that after PK, a biomechanically stable and histologically continuous DM can enable Descemetorhexis outside the failed graft and transplantation of a DMEK graft larger than the previous PK. This may provide more endothelial cells for transplantation.