Naqvi Ali H, Khan Saad A, Ali Mahmood, Moqeet Muhammad A, Muazzam Hira, Ullah Khan Fahim, Saad Muhammad, Ahmed Waleed, Akhtar Farah, Khan Wajid A
Ophthalmology, Al-Shifa Trust Eye Hospital, Rawalpindi, PAK.
Cornea and Refractive Surgery, Al-Shifa Trust Eye Hospital, Rawalpindi, PAK.
Cureus. 2024 Dec 26;16(12):e76411. doi: 10.7759/cureus.76411. eCollection 2024 Dec.
Glaucoma, particularly open-angle glaucoma (OAG), is a leading cause of irreversible blindness, associated with optic nerve damage, retinal ganglion cell death, and visual field defects. Corneal biomechanical properties and cellular components, such as corneal nerve and keratocyte densities assessed by in vivo confocal microscopy (IVCM), may serve as biomarkers for glaucoma progression. This study aimed to explore the relationship between corneal nerve parameters, keratocyte density, and optical coherence tomography (OCT)-derived retinal nerve fiber layer (RNFL) thickness in primary open-angle glaucoma (POAG) patients and controls.
This case-control study was conducted at Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan, from January 2023 to October 2024. It included 26 eyes of 17 glaucoma patients and 28 eyes of 18 age-matched controls. POAG was diagnosed based on elevated intraocular pressure (IOP), optic disc changes, RNFL defects, and visual field abnormalities. Participants underwent full ophthalmic evaluation, including OCT for RNFL thickness, specular microscopy, and corneal confocal microscopy (CCM). Data were analyzed using IBM SPSS Statistics for Windows, Version 26.0 (Released 2019; IBM Corp., Armonk, New York, United States), with Spearman's correlation and linear regression for association analysis.
Anterior stromal keratocyte density was significantly lower in glaucoma patients (436.63±145.44 cells/mm²) compared to controls (546.54±141.20 cells/mm²; p=0.007). No significant difference was found in posterior stromal keratocyte density (p=0.788). Corneal nerve parameters showed a higher nerve fiber length in glaucoma patients (19.25±5.74 mm/mm²), but the difference was not significant (p=0.143). Nerve branch density was significantly higher in glaucoma patients (40.22±23.44 branches/mm²) compared to controls (26.12±10.17 branches/mm²; p=0.054). Specular microscopy revealed significantly lower endothelial cell density in glaucoma patients (2159.8±393.39 cells/mm²) compared to controls (2474.15±272.59 cells/mm²; p=0.002). OCT measurements showed a significantly thinner global RNFL in glaucoma patients (69.79±24.79 µm) compared to controls (98.86±9.04 µm; p<0.001). Spearman's correlation analysis showed that anterior keratocyte density was positively correlated with global (r=0.294; p=0.045), superior (r=0.312; p=0.031), and inferior quadrant RNFL thickness (r=0.285; p=0.049). It was also negatively correlated with central corneal thickness (CCT) (r=-0.367; p=0.039). In multivariate analysis, the duration of glaucoma was significantly associated with RNFL thickness (p=0.011).
This study found that anterior stromal keratocyte density was positively correlated with RNFL thickness, suggesting a potential link between corneal cellular changes and glaucoma severity. Endothelial cell density was significantly lower in glaucoma patients, which may reflect the disease's impact or the effect of medications on corneal health. While corneal nerve parameters did not show significant differences, these findings highlight the importance of corneal biomechanical properties in glaucoma pathophysiology. Further studies with larger sample sizes and longer follow-up periods are needed to confirm these findings and explore the role of corneal parameters in glaucoma progression.
青光眼，尤其是开角型青光眼（OAG），是不可逆性失明的主要原因，与视神经损伤、视网膜神经节细胞死亡和视野缺损相关。角膜生物力学特性和细胞成分，如通过体内共聚焦显微镜（IVCM）评估的角膜神经和角膜细胞密度，可能作为青光眼进展的生物标志物。本研究旨在探讨原发性开角型青光眼（POAG）患者和对照组中角膜神经参数、角膜细胞密度与光学相干断层扫描（OCT）衍生的视网膜神经纤维层（RNFL）厚度之间的关系。
本病例对照研究于2023年1月至2024年10月在巴基斯坦拉瓦尔品第的阿尔希法信托眼科医院进行。研究包括17例青光眼患者的26只眼和18例年龄匹配的对照组的28只眼。POAG根据眼压升高（IOP）、视盘改变、RNFL缺损和视野异常进行诊断。参与者接受了全面的眼科评估，包括用于测量RNFL厚度的OCT、镜面显微镜检查和角膜共聚焦显微镜检查（CCM）。使用IBM SPSS Statistics for Windows 26.0版（2019年发布；IBM公司，美国纽约州阿蒙克）进行数据分析，采用Spearman相关性分析和线性回归进行关联分析。
青光眼患者前基质角膜细胞密度（436.63±145.44个细胞/mm²）显著低于对照组（546.54±141.20个细胞/mm²；p = 0.007）。后基质角膜细胞密度无显著差异（p = 0.788）。角膜神经参数显示青光眼患者的神经纤维长度较长（19.25±5.74 mm/mm²），但差异不显著（p = 0.143）。青光眼患者的神经分支密度（40.22±23.44个分支/mm²）显著高于对照组（26.12±10.17个分支/mm²；p = 0.054）。镜面显微镜检查显示青光眼患者的内皮细胞密度（2159.8±393.39个细胞/mm²）显著低于对照组（2474.15±272.59个细胞/mm²；p = 0.002）。OCT测量显示青光眼患者的整体RNFL显著变薄（69.79±24.79 µm），而对照组为（98.86±9.04 µm；p < 0.001）。Spearman相关性分析显示，前角膜细胞密度与整体（r = 0.294；p = 0.045）、上方（r = 0.312；p = 0.031）和下方象限RNFL厚度呈正相关（r = 0.285；p = 0.049）。它也与中央角膜厚度（CCT）呈负相关（r = -0.367；p = 0.039）。在多变量分析中，青光眼病程与RNFL厚度显著相关（p = 0.011）。
本研究发现前基质角膜细胞密度与RNFL厚度呈正相关，提示角膜细胞变化与青光眼严重程度之间可能存在联系。青光眼患者的内皮细胞密度显著降低，这可能反映了疾病的影响或药物对角膜健康的作用。虽然角膜神经参数没有显示出显著差异，但这些发现突出了角膜生物力学特性在青光眼病理生理学中的重要性。需要进行更大样本量和更长随访期的进一步研究来证实这些发现，并探索角膜参数在青光眼进展中的作用。
