Clinical trial NCT04495491: Predicting the Effect of Laser Peripheral Iridotomy
Official title: Prediction of the Degree of Angle Opening Distance in Patients With Primary Angle Closure Suspect After Laser Peripheral Iridotomy
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Glaucoma
Keywords: laser peripheral iridotomy
primary angle closure suspect
angle closure mechanism
Lead sponsor: Zhongshan Ophthalmic Center, Sun Yat-sen University
Sponsor class: OTHER
First posted: 2020-07-31
Enrollment: 200
Sex: ALL
Minimum age (years): 20
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: OTHER
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Chinese Patient was diagnosed of primary angle closure angle suspect

Brief summary: This study will compare the angle parameters of patients with PACS before and after LPI. The investigators will analyze the results of patients with different angle closure mechanisms before and after LPI, and participants hope to find the structural parameters for predicting the effect of LPI.

Detailed description: Primary angle-closure glaucoma is the leading cause of blindness worldwide. It is associated with increased intraocular pressure, which causes optic nerve damage and field defects if untreated. The aqueous humor leaves the anterior chamber through the trabecular meshwork and flows into the aqueous vein and the superior scleral vein through the collector channels and Schlemm's canal. If the trabecular meshwork is not blocked, a wide angle allows enough aqueous humor to drain out. The iris corneal translocation may lead to angle-closure glaucoma.

Laser peripheral iridectomy is recognized as the best surgical method to relieve pupil block. Previous studies have shown increased anterior chamber depth (ACD), area (ACA), and volume (ACV), and increased Angle open distance (AOD) after LPI surgery.

However, postoperative outcomes of LPI were not the same for patients with different angle closure mechanisms.

Postoperative outcomes for LPI were best for patients with pupillary block type, but were moderate for patients with plateau iris group and mixed group.

The purpose of this study, conducted in Chinese subjects, aims to use UBM to evaluate changes in the anterior segment parameters of LPI, and to propose methods to predict postoperative outcomes of LPI.

Eligibility criteria: Inclusion Criteria:

1. Patient was diagnosed of primary angle closure angle suspect;
2. received ultrasound Biomicroscopy before and after laser peripheral iridotomy;
3. Voluntary participation in this study;
4. Have enough language comprehension ability;
5. Patient or his legal representative has sign the informed consent.

Exclusion Criteria:

1. severe health problems resulting in a life expectancy of less than 1 year;
2. previous intraocular surgery or penetrating eye injury;
3. media opacity preventing laser peripheral iridotomy;
4. Researchers think not suitable to participate in this clinical trial subjects;
5. Refused to sign the informed consent.;
6. There are important viscera function failure or other serious disease, including clinical related coronary artery disease, cardiovascular disease or myocardial infarction into the group of the first six months; serious neurological or psychiatric illness; serious infections; coagulant function abnormality; general active infectious diseases; malignant tumor; serious immune diseases.

Primary outcomes:
measure: the changes in anterior opening distance before and after LPI
timeFrame: between the baseline and 1 hour before discharge
Secondary outcomes:
Other outcomes:
Locations:
city: Guangzhou
country: China
facility: Zhongshan Ophthalmic Center, Sun Yat-San Univerdity
state: Guangdong
Study officials:
affiliation: Zhongshan Ophthalmic Center, Sun Yat-San University
name: Mingkai Lin, MD
role: STUDY_CHAIR
References:
citation: He M, Jiang Y, Huang S, Chang DS, Munoz B, Aung T, Foster PJ, Friedman DS. Laser peripheral iridotomy for the prevention of angle closure: a single-centre, randomised controlled trial. Lancet. 2019 Apr 20;393(10181):1609-1618. doi: 10.1016/S0140-6736(18)32607-2. Epub 2019 Mar 14.
citation: He M, Friedman DS, Ge J, Huang W, Jin C, Lee PS, Khaw PT, Foster PJ. Laser peripheral iridotomy in primary angle-closure suspects: biometric and gonioscopic outcomes: the Liwan Eye Study. Ophthalmology. 2007 Mar;114(3):494-500. doi: 10.1016/j.ophtha.2006.06.053. Epub 2006 Nov 21.
citation: He M, Foster PJ, Ge J, Huang W, Zheng Y, Friedman DS, Lee PS, Khaw PT. Prevalence and clinical characteristics of glaucoma in adult Chinese: a population-based study in Liwan District, Guangzhou. Invest Ophthalmol Vis Sci. 2006 Jul;47(7):2782-8. doi: 10.1167/iovs.06-0051.