Primary%20open-angle%20glaucoma Diagnosis
History
- Review of history of family, ocular and systemic diseases (eg DM, hypertension, asthma, vascular disorders) are obtained during initial evaluation
- Current medications (ocular and systemic) being taken and history of adverse reactions to these drugs
- History of eye surgery
- Cataract surgery, photorefractive keratectomy may result in a falsely low intraocular pressure (IOP)
- Ocular trauma (eg contusion)
Physical Examination
Visual Acuity
- Measure and determine best corrected near and distance visual acuity
Examination of Pupils
- Examine for reactivity and presence of afferent pupillary defect
Examination of the Fundus
- Look for cupping, macular degeneration, disc edema, retinovascular occlusion, optic nerve pallor and pits
- Cupping is the hallowing out of the optic nerve or “disc” and a diameter of >50% of the vertical disc signifies glaucoma
Imaging
Biomicroscopy
- Assess the anterior chamber depth and angle, look for corneal defects, iris pathology or inflammation using slit-lamp biomicroscope to help determine if there is presence of a secondary cause of intraocular pressure (IOP) elevation
Tonometry
- Bilateral measurement of IOP using Goldmann applanation tonometry done at varying times of the day or on different days to detect fluctuations
- It is recommended to measure untreated IOP more than once prior to starting treatment
Gonioscopy
- Important to exclude secondary causes of IOP (eg peripheral anterior synechiae, angle neovascularization, angle recession, etc) or exclude diagnosis of angle-closure glaucoma
Examination of Optic Nerve Head and Retinal Nerve Fiber Layer
- Changes in these structures often precede visual field loss in glaucoma patients
- Look for changes such as optic disc hemorrhages, peripapillary choroidal atrophy
- Performed using magnified stereoscopic visualization, digital photography and stereophotographic techniques with red-free illumination
Other Tests
- Central corneal thickness (CCT) measurement (pachymetry) helps to determine level of risk for ocular damage
- Visual field test (eg automated static threshold perimetry, short-wavelength automated perimetry or SWAP, frequency doubling technology or FDT)
- Computer-based quantitative imaging of the optic nerve head and retinal nerve fiber layer using one of the following modalities: Optical Coherence Tomography (OCT), confocal scanning laser ophthalmoscopy (CLSO: Heidelberg Retinal Tomogram, HRT) and scanning laser polarimetry
- For early detection of nerve fiber layer thinning, facilitating earlier diagnosis and detection of optic nerve damage
- Serves as an adjunct to the clinical examination of the optic nerve head