[关键词]
[摘要]
原发性色素播散综合征(PDS)是一种以虹膜色素上皮色素颗粒脱落并沉积于小梁网等眼前节结构为特征的疾病。该病可导致眼压升高,进而引起视神经损害,并进展为色素性青光眼(PG)。PDS多见于年轻近视人群,临床表现隐匿、多样,兼具散发性和家族遗传性特点。目前已发现的致病基因有与黑色素合成与黑色素体稳态相关基因如PMEL、MC1R、SLC45A2、TYR等,以及与眼发育/眼前节结构发育相关基因如CPAMD8、GSAP、GRM5等。PDS的发病机制与虹膜后弓、反向瞳孔阻滞引起的房水动力学异常、虹膜与晶状体悬韧带摩擦所致的持续性色素释放密切相关; 小梁网被色素颗粒机械性阻塞、小梁网细胞吞噬色素负荷增加引起细胞损伤和小梁网结构塌陷,加剧持续性高眼压及青光眼性视神经病变。单纯PDS以定期随访与评估眼压升高的风险为主,可行激光虹膜周切术以缓解虹膜后弓状态; PG治疗以控制眼压为核心,包括药物、激光小梁成形术及滤过/引流手术等,需长期随访。有待开发与人类致病基因相同且具PDS表型的实验动物模型,以深入研究PDS的发病机制。
[Key word]
[Abstract]
Primary pigment dispersion syndrome(PDS)is characterized by pigment granules released from the pigment epithelium of iris, and their deposition in anterior segment of eye, particularly in the trabecular meshwork(TM). This condition may lead to elevated intraocular pressure(IOP),which further causes optic nerve damage, and progresses to pigmentary glaucoma(PG). PDS predominantly affects young myopic individuals and shows heterogeneous clinical manifestations. It may occur sporadically or in familial inheritance. It has been reported that the pathogenic genes include those involved in melanogenesis and melanosome homeostasis(e.g., PMEL, MC1R, SLC45A2, and TYR), and genes related to ocular development and anterior segment formation(e.g., CPAMD8, GSAP, and GRM5).The pathogenesis of PDS is closely associated with posterior iris concavity and reverse pupillary block, which may change the dynamics of aqueous humor, along with persistent liberation of pigmented granules by friction of iris and zonules. Pigmented granules accumulating in the TM may cause mechanical obstruction of TM, and increase the phagocytic burden of the cells, and result in cellular dysfunction and structural damage of TM. All these changes contribute to sustained elevation of IOP and optic neuropathy. Primary management of PDS involves regular follow-up and assessment of the risk of IOP elevation. Laser peripheral iridotomy may be considered to reduce posterior iris concavity in PDS. Treatment of PG focuses on IOP control for long term, which include topical medications, laser trabeculoplasty, and filtering or drainage surgery. Development of experimental animal models harboring human pathogenic genes and exhibiting PDS phenotypes is needed to facilitate in-depth research into the pathogenesis of PDS.
[中图分类号]
[基金项目]
陕西省重点研发计划项目(No.2024SF2-GJHX-39); 空军军医大学临床研究项目(No.2024LC2414)