Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness worldwide, with an estimated 53 million people affected globally in 20204). The prevalence of POAG is particularly high in African populations; for example, African Americans have about three times the prevalence of Caucasians4). Even higher prevalence has been reported in Afro-Caribbean populations4).
POAG in African populations tends to progress rapidly and is often resistant to conventional treatment. A large proportion of glaucoma-related blindness occurs in Africa. In sub-Saharan Africa, the high cost of glaucoma medications and fear of surgery are barriers to proper management, and laser treatment, which is an intermediate therapeutic step, is rarely available.
Multiple factors are involved. Genetically, risk alleles for POAG may be more frequent in African populations4). Anatomically, thinner central corneal thickness has been reported, which is associated with underestimation of intraocular pressure and is also a risk factor for POAG. Socioeconomically, limited access to healthcare leads to delayed diagnosis and treatment, often with advanced disease at presentation. These combined factors contribute to the higher prevalence and severity of POAG in African populations.
In the Advanced Glaucoma Intervention Study (AGIS), African American patients showed a 30% reduction in intraocular pressure when ALT (argon laser trabeculoplasty) was performed first, while Caucasian patients showed a 48% reduction when trabeculectomy was performed first4). Thus, differences in treatment response by race have been reported.
The basic principle of treatment for primary open-angle glaucoma is lowering intraocular pressure1)4). Medication therapy has been widely used as first-line treatment. However, in Africa, drug cost, poor adherence, and side effects are barriers to continued treatment.
Mechanism: A Q-switched Nd:YAG laser selectively targets pigmented cells in the trabecular meshwork, stimulating cellular activity to enhance aqueous humor outflow.
Evidence as first-line treatment: The LiGHT trial showed that SLT provides intraocular pressure reduction equivalent to eye drops and is more cost-effective 3)5). EGS and AAO guidelines recommend SLT as first-line therapy 2)3)4).
Outcomes in African descent populations: The WIGLS (West Indies Glaucoma Laser Study) achieved ≥20% IOP reduction in 78% of African Caribbean participants 4)5).
Other Laser Treatments
ALT (Argon Laser Trabeculoplasty): Induces mechanical changes in the trabecular meshwork or stimulates cellular activity. The AGIS study reported favorable short-term outcomes in African American patients 4).
Micropulse Laser Trabeculoplasty (MLT): Divides energy into short pulses to reduce thermal damage to surrounding tissue. A study in Nigeria reported a 17.2% IOP reduction from baseline.
Transscleral Cyclophotocoagulation (TSCPC): Destroys the ciliary body to reduce aqueous humor production. Used for refractory glaucoma but carries risks of hypotony and phthisis bulbi.
The LiGHT trial (Laser in Glaucoma and Ocular Hypertension Trial) is a multicenter RCT comparing initial treatment with SLT versus eye drops for open-angle glaucoma/OHT 5).
At the 6-year follow-up, the SLT group showed less visual field progression than the eye drop group (19.6% vs 26.8%, p=0.01), and was confirmed to be safe and cost-effective 5). In the SLT group, 90% maintained a drop-free state for 6 years with a maximum of two SLT treatments, and 55.5% required only one SLT5).
SLT has been reported as an ideal treatment approach even in situations where frequent monitoring visits or treatment changes are difficult 5). This characteristic is particularly suitable for glaucoma management in Africa.
Surgery is considered when intraocular pressure control is insufficient with medication or laser therapy. Trabeculectomy is the standard procedure, but success rates tend to be lower in African populations due to an exuberant wound healing response 4).
QIs SLT recommended as first-line treatment for POAG?
A
Based on the results of the LiGHT trial, EGS, AAO, and NICE all recommend SLT as first-line treatment for open-angle glaucoma/OHT 2)3)4)5). SLT shows intraocular pressure lowering equivalent to eye drops, is cost-effective, and resulted in less visual field progression over 6 years compared to the eye drop group 5). SLT is an ideal option, especially for patients with poor adherence to eye drops or in settings where cost is a concern.
High-frequency deep sclerotomy (HFDS) is a MIGS that creates channels in the trabecular meshwork using a high-frequency electrocautery probe via an ab interno approach to facilitate aqueous humor outflow 6).
Wang et al. performed HFDS in two POAG patients in Taiwan and reported IOP reductions of 30% and 33.3% at one year 6). Postoperative corneal endothelial cell loss was mild (7–13%), and no major complications were observed 6). Previous studies have reported mean IOP reductions of 39.2% at 9 months and 42.5% at 72 months after HFDS 6).
HFDS does not require implants or shunts and can be repeated, making it potentially suitable for healthcare settings in Africa 6).
European Glaucoma Society. Terminology and Guidelines for Glaucoma, 5th Edition. 2020.
European Glaucoma Society. Terminology and Guidelines for Glaucoma, 6th Edition. Br J Ophthalmol. 2025.
American Academy of Ophthalmology. Primary Open-Angle Glaucoma Preferred Practice Pattern®. 2020.
Gazzard G, Konstantakopoulou E, Garway-Heath D, et al. LiGHT Trial: six-year results of primary selective laser trabeculoplasty versus eye drops for the treatment of glaucoma and ocular hypertension. Ophthalmology. 2023;130:139-151.
Wang WX, Ko ML. Taiwan’s first clinical reports on the surgical effect of high-frequency deep sclerotomy for treating primary open-angle glaucoma. BMC Ophthalmology. 2025;25:84.
Copy the article text and paste it into your preferred AI assistant.
Article copied to clipboard
Open an AI assistant below and paste the copied text into the chat box.
