Study Purpose and Principle: Amyloidosis is a group of diseases characterized by the deposition of amyloid proteins in tissues and organs throughout the body, with common affected organs including kidneys, heart, nervous system, gastrointestinal tract, and liver. Nowadays, nearly 40 different proteins have been found to form amyloid fibrils in body, among which Systemic Light Chain (AL) Amyloidosis is the most common type of systemic amyloidosis. AL amyloidosis is a plasma cell disorder, with its precursor protein originating from free light chains produced by abnormal plasma cell clones, which form amyloid substances that deposit in tissues and organs causing lesions. In terms of incidence, the incidence of AL amyloidosis is 8-10 cases per million person-years in the United States and is considered a rare disease in our country. AL amyloidosis has an insidious onset, diverse clinical manifestations, and is prone to misdiagnosis and missed diagnosis in clinical practice. The prognosis also has strong heterogeneity and is closely related to the extent of organ involvement at the time of diagnosis. In the past, the incidence of eye involvement in systemic AL amyloidosis patients was low, with various manifestations, only reported as case reports, and not regularly followed up with systemic treatment. Based on this, this project aims to assess the involvement of eyes and its appendages in patients with different stages of systemic light chain amyloidosis, with the goal of clarifying the ocular manifestations of this systemic disease and exploring early diagnostic indicators for the eye.

Primary Objective: To assess the involvement of the anterior segment of the eye, as well as the extraocular soft tissues and muscles, in patients with systemic light chain amyloidosis.

Secondary Objective: To assess the neuro-ophthalmic manifestations and changes in retinal choroidal blood flow in patients with systemic light chain amyloidosis.

Study Design: Observational study.

Study Population and Expected Enrollment: 80 patients with systemic light chain amyloidosis, 50 normal controls.

Study Duration: Six months of follow-up after the last subject is diagnosed and enrolled.

Intervention: Experimental Group: Patients with systemic light chain amyloidosis; Control Group: Subjects without systemic diseases.

Case Group

Inclusion Criteria:

1. Patients diagnosed with "Systemic Light Chain Amyloidosis";
2. No other severe systemic underlying diseases that affect the examination;
3. Subjects voluntarily participate in this study, sign the informed consent form;
4. Age between 18-80 years old, no gender restrictions.

Exclusion Criteria:

1. Patients with eye diseases of clear causes such as ocular surface malignant tumors, corneal perforation, severe eye trauma, etc.;
2. Patients with nystagmus;
3. Severe ocular scar diseases; conjunctival scars with fornix shortening;
4. Current signs of infection, including fever and undergoing antibiotic treatment;
5. Mental abnormalities;
6. Pregnant or breastfeeding women, or women planning to become pregnant within 2 years;
7. NYHA Class IV: Heart disease patients cannot engage in any physical activity, with heart failure symptoms even at rest, and worsening with physical activity;
8. NT-proBNP > 8,500 ng/L.

Control Group

Inclusion Criteria:

1. Stable general condition, not patients with "Systemic Light Chain Amyloidosis";
2. No other severe systemic underlying diseases that affect the examination;
3. Subjects voluntarily participate in this study, sign the informed consent form;
4. Age between 18-80 years old, no gender restrictions.

Exclusion Criteria:

1. Patients with eye diseases of clear causes such as ocular surface malignant tumors, corneal perforation, severe eye trauma, etc.;
2. Patients with nystagmus;
3. Severe ocular scar diseases; conjunctival scars with fornix shortening;
4. Current signs of infection, including fever and undergoing antibiotic treatment;
5. Mental abnormalities;
6. Pregnant or breastfeeding women, or women planning to become pregnant within 2 years.

Source and Selection Method of Case Group: Patients diagnosed with "Systemic Light Chain Amyloidosis" or suspected of having "Systemic Light Chain Amyloidosis" and treated according to relevant diagnostic and treatment standards at tertiary hospitals. They are planned to undergo ocular screening at Zhongshan Ophthalmic Center of Sun Yat-sen University to exclude ocular and adnexal complications. It is expected that 80 cases of systemic light chain amyloidosis will participate in this study.

Source and Selection Method of Control Group: Control group subjects are all sourced from the outpatient department of Zhongshan Ophthalmic Center of Sun Yat-sen University. It is expected that 50 cases of dry eye syndrome/cataract patients will participate in this study.