Ocular Health Assessment Techniques
Slit-lamp technique
Master the standard sequence: diffuse illumination for an overview, then direct focal illumination with a narrow beam (optic section) for depth, indirect illumination for opacities, retroillumination for subtle corneal or vaulted pathology, sclerotic scatter for limbal lesions, and specular reflection for the endothelium. Van Herick estimation is performed at the temporal limbus with a narrow optic section: grade 4 (peripheral depth at least equal to corneal thickness) is open, while grade 2 or less warrants gonioscopy before dilation.
Ophthalmoscopy and gonioscopy
With a condensing lens, keep the beam coaxial with the patient's view: red reflex first, then disc, arcades, macula and periphery. Assess disc colour, margins, cup-to-disc ratio and neuroretinal rim, then vessels and background retina. Gonioscopy (Goldmann mirrored or Zeiss four-mirror) identifies Schwalbe's line, trabecular meshwork, scleral spur and ciliary body band; indentation distinguishes appositional from synechial closure. Shaffer grading 0 to 4 is shorthand for the same observation.
Tonometry
Goldmann applanation remains the reference standard: fluorescein, cobalt blue, mires just touching, aligned to the central cornea, calibrated and repeated. A single reading is a measurement, not a diagnosis; record time of day and corneal thickness, and note factors that falsely lower (thin cornea) or raise (thick cornea, breath-holding, tight collar) the value.
Traps
Pressing on the globe during gonioscopy, omitting topical anaesthetic, misreading a tear-film artefact as pathology, and quoting an intraocular pressure without stating the conditions of measurement. Never applanate an eye with active corneal infection or recent penetrating injury.
Rule of thumb
A grade 2 van Herick at the temporal limbus (peripheral depth roughly one quarter of corneal thickness) means the angle is narrow until gonioscopy proves otherwise.