[Clinical aspects of normal pressure glaucoma]

Area of Science:

• Ophthalmology
• Glaucoma Research
• Clinical Medicine

Background:

• Normal pressure glaucoma (NPG) is a subtype of glaucoma characterized by optic nerve damage and visual field loss despite statistically normal intraocular pressure (IOP).
• Understanding the clinical polymorphism of NPG is crucial for accurate diagnosis and effective management.
• Previous studies have highlighted variations in NPG presentation, but specific correlations with IOP levels within the normal range require further elucidation.

Purpose of the Study:

• To investigate the clinical manifestations of normal pressure glaucoma.
• To identify specific features associated with different levels of intraocular pressure within the normal range in NPG patients.
• To correlate clinical findings with diagnostic parameters for improved diagnosis and treatment strategies.

Main Methods:

• A comprehensive ophthalmologic examination was performed on 76 eyes of 45 patients diagnosed with normal pressure glaucoma.
• Diagnostic tools included tonography, Humphrey-720 computer perimetry, and Nidec fundus-chamber photometry for optic nerve assessment.
• Patients were categorized based on initial intraocular pressure (IOP) levels: <= 20 mm Hg and <= 26 mm Hg.

Main Results:

• Polymorphism in clinical presentations of NPG was observed, with distinct features correlating to initial IOP levels.
• Patients with lower IOP (<= 20 mm Hg) typically presented with older age, normal anterior segment and hydrodynamic parameters, pronounced asymmetric optic disc excavation, and sectorial visual field defects.
• Patients with higher IOP (<= 26 mm Hg) were generally younger, exhibited iris and drainage zone dystrophic changes similar to primary open-angle glaucoma, had low fluid secretion and discharge, symmetric excavation, and diffuse peripheral visual field loss.

Conclusions:

• Clinical manifestations of normal pressure glaucoma exhibit significant polymorphism, influenced by intraocular pressure levels.
• Distinct clinical profiles are associated with lower versus higher IOP within the normal range, aiding in differential diagnosis.
• Recognizing these specific clinical aspects facilitates timely diagnosis and appropriate treatment selection for normal pressure glaucoma patients.