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Ophthalmoscopy Clinical Guide

Techniques for direct and indirect fundus examination in optometric practice.

Last updated: March 2026

Clinical Guide Overview

1. Clinical Importance

Ophthalmoscopy — also called funduscopy — is the examination of the posterior segment of the eye, including the optic disc, retinal vasculature, macula, and peripheral retina. It is one of the most important clinical skills in optometry and is essential for the detection, diagnosis, and monitoring of a wide range of ocular and systemic diseases.

Two principal techniques are used in optometry practice: direct ophthalmoscopy, which provides a high-magnification, upright, monocular view of the posterior pole, and binocular indirect ophthalmoscopy (BIO), which provides a lower-magnification, inverted, stereoscopic, and wider-field view of the entire retina including the peripheral fundus.

Ophthalmoscopy is indicated as a routine component of a comprehensive eye examination, and is particularly important in patients with diabetes mellitus, hypertension, glaucoma, age-related macular degeneration, symptoms of flashes and floaters, unexplained visual loss, neurological symptoms, and family history of retinal disease. Optometrists worldwide are primary providers of this examination and play a critical role in early detection and timely referral.

2. Equipment and Tools

Direct Ophthalmoscope

  • Light source: Halogen or LED illumination. LED models (e.g., Welch Allyn PanOptic, Heine BETA 200) provide brighter, more consistent illumination and longer battery life.
  • Apertures available:
    • Large spot: Routine examination in dilated pupils.
    • Small spot: Undilated or miotic pupils, reduces corneal reflex.
    • Red-free (green) filter: Enhances nerve fibre layer, blood vessels, and haemorrhages.
    • Cobalt blue filter: Used with fluorescein for corneal staining.
    • Slit aperture: Assesses retinal contour (elevation or depression of lesions).
    • Grid aperture: Estimates lesion size relative to disc diameter.
  • Dioptre wheel: Corrects for patient and examiner refractive error. Range typically −25D to +25D. Green numbers = plus lenses; red/black numbers = minus lenses.
  • Magnification: Approximately 15× in an emmetropic eye. Field of view approximately 5–8° (small area around posterior pole only).

Binocular Indirect Ophthalmoscope (BIO)

  • Headset: Worn on examiner's head. Contains binocular eyepieces, condensing lens holder, and bright illumination source. Provides stereoscopic (3D) view.
  • Condensing (hand-held) lens: Held approximately 5–7 cm from patient's eye. Common options:
    • +20D: Standard lens. Field ~45°, magnification ~3×. Best balance of field and detail.
    • +28D / +30D: Wider field (~53°), lower magnification (~2×). Useful for peripheral examination.
    • +14D / +15D: Higher magnification (~5×), narrower field. Better detail of disc and macula.
  • Image orientation: BIO produces an inverted and laterally reversed image. Superior retina appears inferior in the image; nasal retina appears temporal. This must be mentally corrected during examination and documentation.
  • Scleral indenter: A probe used with BIO to indent the sclera, bringing peripheral and pre-equatorial retina into view. Essential for examination of the vitreous base and ora serrata.

Instrument Preparation

  1. Charge / check batteries: Dim or flickering light significantly degrades the examination. Use rechargeable handles and check charge before each clinical session.
  2. Set dioptre wheel to zero (direct): Adjust for your own refractive error if not wearing spectacles during examination.
  3. BIO interpupillary distance: Set IPD on the BIO headset to match your own PD. Incorrect IPD causes image doubling and eye strain.
  4. Lens cleanliness: Ensure condensing lens is clean and free of smudges. Use lens tissue — never rub with clothing.

3. Patient Preparation

Dilation Protocol

Pupil dilation is strongly recommended for a complete fundus examination. An undilated examination provides only a limited view of the posterior pole and renders peripheral retinal examination virtually impossible.

Standard mydriatic agents:

AgentConcentrationOnsetDurationNotes
Tropicamide0.5% / 1%15–20 min4–6 hoursFirst-line for dilation; minimal cycloplegia
Phenylephrine2.5% / 10%15–20 min3–5 hoursSympathomimetic; add to tropicamide for better dilation. Avoid 10% in cardiovascular disease.
Cyclopentolate0.5% / 1%30–45 min6–24 hoursUsed when cycloplegia required (children, cycloplegic refraction)

Procedure: Instil one drop of tropicamide 1% ± phenylephrine 2.5% into each eye. Wait 20–30 minutes. Pupil should dilate to ≥5 mm for adequate peripheral examination.

Pre-Dilation Assessment

  1. Van Herick angle assessment: Always perform before dilation. Grade 1–2 indicates narrow angle — assess risk of angle closure before proceeding. Consider gonioscopy.
  2. IOP measurement: Measure before dilation if tonometry is planned (dilation does not substantially affect IOP in open-angle patients but ensures baseline is recorded).
  3. Document allergy history: Ask about allergy to any eye drops or medications before instillation.
  4. Driving and safety counselling: Advise patient that near vision will be blurred and light sensitivity will be present for 4–6 hours. Patient should not drive after dilation. Arrange transport or plan appointment accordingly.
  5. Informed consent: Explain the procedure, its purpose, and the above effects. Document consent in records.

Contraindications to Dilation

  • Narrow or closed anterior chamber angle: Risk of precipitating acute angle-closure glaucoma. Perform van Herick first; refer for gonioscopy if angle is narrow.
  • Known allergy to mydriatic agents or preservatives (benzalkonium chloride).
  • Recent penetrating injury or open globe: Do not instil any drops until surgical assessment completed.
  • Patient must drive immediately after appointment and no alternative transport available.
  • Iris-fixated IOL or angle-supported IOL: Dilation may displace or damage the lens — seek ophthalmology guidance.
  • Phenylephrine 10% caution: Avoid in severe hypertension, ischaemic heart disease, hyperthyroidism, or concurrent MAOI use.

4. Direct Ophthalmoscopy Technique

Preparation

  1. Darken the room as much as possible. A dark room dilates the pupil further and improves red reflex visibility.
  2. Ask patient to remove spectacles. Contact lenses may be left in unless removal is planned.
  3. Examiner should remove their own spectacles if the dioptre wheel can compensate (most examiners with mild refractive error). Examiner with high astigmatism should wear spectacles.
  4. Set dioptre wheel to zero initially, or to the examiner's own refractive error (in minus) if not wearing spectacles.
  5. Set aperture to large spot (dilated pupil) or small spot (undilated pupil).

Red Reflex Examination

Purpose: The red reflex is the reflection of light off the tapetal fundus, seen as an orange-red glow through the pupil. It should be assessed before close examination.

  1. Stand approximately 50 cm from the patient at eye level.
  2. Hold ophthalmoscope up to your right eye to examine the patient's right eye. Use your left eye for the patient's left eye.
  3. Direct light beam into the patient's pupil. Observe the red reflex through the viewing aperture.
  4. A bright, even, orange-red glow indicates a clear optical media.
  5. Brückner test (simultaneous red reflex): Examine both eyes simultaneously from ~50 cm. Asymmetry in brightness or colour may indicate anisometropia, strabismus, or media opacity. A brighter reflex in one eye may indicate amblyopia risk.

Abnormal Red Reflex — Common Causes:

  • Dark spot(s) in reflex: Lens opacity (cataract), vitreous floater, corneal scar.
  • Absent reflex (white/leukocoria): Retinoblastoma (child — urgent referral), dense cataract, vitreous haemorrhage, retinal detachment.
  • Dull/dark reflex: Dense media opacity, vitreous haemorrhage, very dark fundus pigmentation.
  • Asymmetric reflex: Strabismus, significant anisometropia, unilateral cataract.

Close Fundus Examination

  1. Approach from temporal side: Move in at approximately 15° temporal to the patient's line of sight. This aligns your approach to view the optic disc directly.
  2. Distance: Get as close as possible to the patient (~2–3 cm). Resting your hand on the patient's cheek or forehead for stability is acceptable. Closer = larger field of view and less corneal reflection.
  3. Ask patient to fixate straight ahead (not at the ophthalmoscope light). For macula view, ask patient to look directly at the light.
  4. Focus on the optic disc first: Follow a vessel proximally (towards the disc) until the disc comes into view. Adjust the dioptre wheel to sharpen focus on the disc.
  5. Dioptre wheel adjustment rule:
    • If disc is out of focus and patient is myopic, turn wheel towards minus (red numbers).
    • If patient is hyperopic, turn towards plus (green numbers).
    • Keep adjusting until the disc margin is as sharp as possible.
  6. Systematically examine: Optic disc → superior arcade → inferior arcade → nasal retina → temporal retina → macula.
  7. Macula examination: Ask patient to look directly at the ophthalmoscope light. This centres the fovea in the beam. Examine briefly — the macula is light-sensitive. Note foveal reflex, drusen, pigmentary changes, haemorrhages.

Estimating Cup-to-Disc Ratio (Direct)

The optic cup is the pale central depression within the optic disc. The cup-to-disc ratio (CDR) is the ratio of the cup diameter to the total disc diameter.

  • Always assess the vertical CDR — clinically most relevant for glaucoma detection.
  • Normal vertical CDR: ≤0.5. However, large physiological cups (up to 0.7–0.8) can be normal in large discs.
  • Asymmetry of CDR between eyes of >0.2 is clinically significant regardless of absolute CDR value.
  • Use the slit aperture to assess disc elevation or cupping — a slit beam across the disc highlights contour changes.
  • Direct ophthalmoscopy is monocular — no stereo depth perception. BIO or slit lamp with fundus lens is superior for disc stereo assessment.

Limitations of Direct Ophthalmoscopy

  • Small, monocular field of view (~5–8°). Cannot view peripheral retina.
  • No stereopsis — depth assessment limited.
  • Requires patient cooperation and proximity to examiner.
  • Poor view through miotic pupils, dense media opacities.
  • Corneal and lens reflexes can obscure view.
  • Not suitable for peripheral retinal examination or vitreous base assessment.

5. Binocular Indirect Ophthalmoscopy (BIO) Technique

BIO Setup

  1. Fit the BIO headset securely. Set IPD on the eyepieces to match your own interpupillary distance.
  2. Adjust the headset so the illumination spot is centred and comfortable. The beam should be aligned with the optical axis of the eyepieces when looking straight ahead.
  3. Darken the room completely. Dilation is essential for BIO — pupil ≥6 mm preferred.
  4. Patient positioned supine on an examination chair/couch for peripheral examination, or seated for posterior pole assessment.
  5. Select condensing lens (typically +20D for routine examination).

BIO Examination Technique

  1. Position: Stand approximately 50–60 cm from the patient's eye (arm's length). For the supine patient, stand at the head of the chair/couch.
  2. Instruct patient to fixate straight ahead (at a spot on the ceiling). Both eyes should remain open to minimise squeezing.
  3. Hold the condensing lens: Between thumb and forefinger, with the anti-reflection (AR) coated side facing the patient. Hold steady ~5–7 cm from the cornea. Rest your remaining fingers gently on the patient's forehead or cheek for stability.
  4. Direct illumination through the pupil: Align the illumination beam through the lens and into the pupil. A fundus image (inverted) will appear within the condensing lens.
  5. Focus: Move the lens slightly forward or backward to bring the fundus image into sharp focus. The optimal lens position is at its focal point anterior to the patient's eye. Adjust your own head position (forward/backward) to refocus if necessary.
  6. Remember image inversion: The image is inverted and laterally reversed. To view the superior retina, ask the patient to look up (lens moves — inferior image in your view). To examine the right side of retina, patient looks right (image appears on your left).
  7. Systematic examination: Start at the posterior pole (disc, macula), then follow each vascular arcade into the periphery: superior → inferior → nasal → temporal.
  8. Peripheral examination: Ask patient to look in the direction of the area to be examined. Move yourself to mirror that direction. For the extreme periphery and ora serrata, scleral indentation may be required.

Scleral Indentation Technique

Purpose: Brings the peripheral retina (anterior to the equator) and the vitreous base into view. Essential for examining retinal tears, lattice degeneration, and ora serrata.

  1. Instil topical anaesthetic before indentation for patient comfort.
  2. Patient supine. Ask patient to look in the direction opposite to the area being indented (indenting at 12 o'clock requires patient to look down).
  3. Place the tip of the scleral indenter against the closed eyelid or at the lid margin, approximately 6–8 mm posterior to the limbus (over the pars plana for extreme periphery).
  4. Apply gentle, steady inward pressure. Observe the tent-shaped indentation appearing in the fundus image via BIO.
  5. Roll the indenter gently to view the vitreous base and ora serrata.
  6. Examine all clock hours systematically. Full 360° indentation is routine in patients with high myopia, flashes/floaters, or vitreous syneresis.

Contraindications to indentation: Recent surgery, open globe, suspected retinal detachment extending to the periphery being indented (relative contraindication — proceed with caution), extreme pain.

6. Systematic Fundus Examination

A consistent sequence prevents missed findings. Recommended order: Optic disc → Peripapillary retina → Superior arcade → Inferior arcade → Nasal retina → Temporal retina → Macula → Periphery (with BIO).

1. Optic Disc

  • Size: Normal disc diameter 1.5–2.0 mm. Large disc = larger physiological cup possible. Small disc = risk of crowding (NAION, pseudopapilloedema).
  • Shape: Normally round or slightly vertically oval. Tilted disc (common in myopia) may mimic inferior pallor or nasal RNFL thinning.
  • Colour: Healthy rim is pink-orange. Pallor of rim = optic atrophy. Hyperaemia = papilloedema, optic neuritis.
  • Margin: Should be sharp and well-defined. Blurred superior/inferior margins suggest papilloedema or optic neuritis. Nasal margin normally slightly blurred physiologically.
  • Cup-to-disc ratio (CDR): Vertical CDR ≤0.5 normal. Apply ISNT rule: Inferior ≥ Superior ≥ Nasal ≥ Temporal rim thickness. Violation, especially inferior or superior, suggests glaucoma.
  • Disc haemorrhages: Flame or splinter haemorrhage at disc margin. Strongly associated with normal tension glaucoma and progressive RNFL loss. Requires monitoring and possible referral.
  • Neovascularisation of disc (NVD): New vessel fronds on or within one disc diameter of the disc. Proliferative diabetic retinopathy — urgent ophthalmology referral.

2. Retinal Vasculature

  • Artery:vein (A:V) ratio: Normal ~2:3. Arteries are brighter, lighter red with a central light reflex. Veins are darker, wider. Generalised arterial narrowing seen in hypertension and arteriosclerosis.
  • AV nipping / crossing changes: Compression of vein at AV crossing (vein appears to taper). Grades 1–3. Risk factor for branch retinal vein occlusion (BRVO). Hypertensive retinopathy sign.
  • Vessel wall changes: Copper wiring (increased light reflex, Grade 2 hypertension), silver wiring (severe arteriosclerosis, narrow arteries appear white).
  • Haemorrhages: Flame (superficial RNFL — hypertension, CRVO/BRVO), dot-blot (deeper retina — diabetic retinopathy), preretinal/subhyaloid (between retina and vitreous — proliferative disease).
  • Neovascularisation elsewhere (NVE): New vessels elsewhere on retina. Proliferative diabetic retinopathy.

3. Macula & Fovea

  • Foveal reflex: Bright central pinpoint reflex in young, healthy eyes. Loss indicates early macular disease (oedema, ERM, atrophy).
  • Drusen: Hard drusen (small, discrete, yellow dots — benign age-related). Soft/confluent drusen (larger, indistinct margins — intermediate AMD, higher progression risk).
  • Pigmentary changes: Focal hyperpigmentation or hypopigmentation. RPE atrophy (geographic atrophy in AMD), pigment clumping in diabetic retinopathy.
  • Macular oedema: Retinal thickening, loss of foveal reflex, cystoid spaces. Seen in diabetic maculopathy, BRVO/CRVO, post-surgical, uveitis. Confirm with OCT.
  • Subretinal fluid / membrane: Grey-green subretinal lesion with adjacent haemorrhage or fluid — suspect choroidal neovascularisation (CNV / neovascular AMD). Urgent referral.
  • Cherry red spot: Pale white retinal oedema surrounding fovea (fovea appears red by contrast). Central retinal artery occlusion (CRAO) — ophthalmic emergency.

4. Peripheral Retina (BIO Required)

  • Lattice degeneration: Oval or linear areas of retinal thinning with pigmented lattice pattern. Predisposes to retinal tears. Common in myopes (6–8% prevalence). Examine all clock hours.
  • Retinal tears: Horseshoe (flap) tear — flap of retina attached anteriorly to vitreous. Operculated hole — free operculum floating in vitreous. Symptomatic tears (with flashes/floaters) require urgent referral for laser or cryotherapy.
  • Retinal detachment (RD): Elevated, grey, billowing retina. Loss of underlying choroidal detail. Macular-on RD — semi-urgent referral (within 24 hours). Macular-off RD — urgent same-day referral.
  • Peripheral cystoid degeneration: Common, benign. White, bubbly appearance at the ora serrata. Not pre-malignant.
  • Choroidal naevus: Flat, grey-brown pigmented lesion. Monitor for growth. Suspicious features: orange pigment (lipofuscin), subretinal fluid, thickness >2 mm, acoustic hollowness, diameter >5 mm.

7. Key Fundus Findings and Interpretation

Diabetic Retinopathy — Classification & Management

StageFindingsManagement
No DRNormal fundusAnnual review; optimise systemic control
Mild NPDRMicroaneurysms onlyAnnual review; systemic optimisation (HbA1c, BP, lipids)
Moderate NPDRMicroaneurysms, dot-blot haemorrhages, hard exudates, cotton wool spots6-monthly review; shared care with physician
Severe NPDR4-2-1 rule: haemorrhages in all 4 quadrants, venous beading in ≥2 quadrants, IRMA in ≥1 quadrantRefer ophthalmology within 4 weeks
PDRNVD, NVE, vitreous haemorrhage, tractional RDUrgent ophthalmology referral; panretinal photocoagulation (PRP) or anti-VEGF
Diabetic Macular Oedema (DMO)Retinal thickening, hard exudates within 500 µm of fovea; may occur at any DR stageReferral for OCT and intravitreal anti-VEGF (first-line) or laser

Hypertensive Retinopathy — Keith-Wagener-Barker Classification

GradeFindingsManagement
Grade 1Mild arterial narrowing, increased light reflex ("copper wiring")Optimise BP control; annual review
Grade 2Moderate narrowing, AV nipping, silver wiringConfirm BP with physician; 6-monthly eye review
Grade 3Flame haemorrhages, cotton wool spots, hard exudatesUrgent physician referral for BP management; ophthalmology referral
Grade 4Grade 3 + papilloedemaSame-day emergency referral — hypertensive crisis

Age-Related Macular Degeneration (AMD)

StageFindingsManagement
Early AMDSmall/medium drusen (<125 µm), no pigmentary changeAnnual review; lifestyle counselling (smoking cessation, diet)
Intermediate AMDLarge drusen (≥125 µm) and/or pigmentary abnormalitiesConsider AREDS2 supplements; 6-monthly review; home Amsler monitoring
Late — Geographic AtrophyWell-demarcated area of RPE/photoreceptor atrophy, choroidal vessels visibleRefer to ophthalmology; low vision support; monitor fellow eye
Late — Neovascular (wet AMD)Subretinal fluid, haemorrhage, grey/green membrane, sudden VA loss, metamorphopsiaUrgent ophthalmology referral (within 1–2 weeks); intravitreal anti-VEGF

Glaucomatous Disc Changes

  • Progressive CDR enlargement — requires serial disc photography or OCT RNFL for confirmation.
  • Inferior or superior notching — loss of neuroretinal rim at 6 or 12 o'clock. ISNT rule violation.
  • RNFL defects: Wedge-shaped dark defects in the RNFL best seen with red-free filter. Superior and inferior RNFL bundles are most susceptible.
  • Disc haemorrhage: Splinter haemorrhage at the disc margin. Transient finding — may be missed without regular examination. Indicates active nerve fibre loss.
  • Bayoneting / baring of circumlinear vessel: Vessel appears to kink as it disappears into a deepened cup. Indicates acquired cupping.
  • Nasalisation of vessels: Vessels pushed nasally due to enlarged cup.

Urgent / Emergency Referral Criteria

  • Same-day emergency: CRAO (cherry red spot + sudden painless VA loss), Grade 4 hypertensive retinopathy (papilloedema + hypertensive crisis), macular-off retinal detachment, vitreous haemorrhage with no view, suspected endophthalmitis.
  • Within 24 hours: Macular-on retinal detachment, symptomatic retinal tear (flashes + floaters), acute papilloedema of unknown cause.
  • Within 1–2 weeks: Neovascular AMD (new onset wet AMD), new proliferative diabetic retinopathy, CRVO/BRVO with macular involvement.
  • Within 4 weeks: Severe NPDR, new disc haemorrhage with progressive glaucoma, suspicious choroidal naevus with high-risk features.

8. Grading and Documentation

Documentation Essentials

  • Optic disc: Vertical CDR (each eye), rim colour, margin appearance, presence of haemorrhage, disc size estimate (small/average/large), NVD.
  • Vasculature: A:V ratio, AV crossing changes, vessel calibre, haemorrhage type and location (clock hour), exudates, NVE.
  • Macula: Foveal reflex present/absent, drusen (number and size), pigmentary changes, oedema, membrane, haemorrhage.
  • Periphery: Lattice degeneration (clock hour, size), tears (type, clock hour), naevi (size, features), pigmentary changes.
  • Media clarity: Document view quality — "Good view" or "View limited by [reason]."
  • Dilation: Document agent, concentration, time instilled, pupil size achieved.
  • Fundus drawings: Use standardised fundus diagram templates (right eye on right, left eye on left). Annotate findings with clock hour position and estimated disc diameter distances.
  • Fundus photography: Obtain where available for baseline documentation. Essential for disc and macular lesions that require longitudinal monitoring.

Lesion Localisation — Clock Hour & Disc Diameters

Clock hour: Describe retinal lesion position using clock face (1–12) relative to the disc or fovea. Always specify whether referring to the right or left eye (the same clock hour position is a mirror image).

Disc diameter (DD): The optic disc diameter (~1.5 mm) is used as a standard unit of measurement for lesion size and distance from landmarks. Example: "Lattice degeneration at 2 o'clock, 4–5 DD from the disc, approximately 1 DD in length."

Macular lesions: Describe in relation to the fovea and the foveal avascular zone (FAZ, ~0.5 mm diameter). "Hard exudates within 1 DD of fovea" = clinically significant.

9. Special Populations

Paediatric Patients

  • Red reflex screening: Brückner test at every infant/child examination. Leukocoria (white reflex) is an ocular emergency — must exclude retinoblastoma.
  • Retinopathy of prematurity (ROP): Screening by ophthalmologist in premature infants (<31 weeks or <1500g). Optometrist role is in follow-up monitoring post-discharge and ensuring screening referrals are made.
  • Paediatric fundus findings: Myelinated nerve fibres (white, feathery, extends from disc — benign), disc drusen, optic nerve hypoplasia.
  • Cooperation: Use handheld direct ophthalmoscope first. BIO requires child to be supine. Parental assistance valuable. Examination under anaesthesia (EUA) if full assessment not possible.

Diabetic Patients

  • Annual dilated fundus examination is the minimum standard for all diabetic patients. More frequent examination as DR severity increases.
  • Document HbA1c, BP, lipids, and duration of diabetes — systemic control directly correlates with DR risk and progression.
  • Maculopathy assessment is critical: Diabetic maculopathy (DMO) is the leading cause of visual impairment in working-age adults in developed countries. OCT is superior to ophthalmoscopy alone for confirming macular oedema.
  • Pregnancy in diabetes: Existing DR can worsen dramatically during pregnancy. Examine at booking and each trimester. Refer immediately for any worsening.

High Myopia (>−6.00D)

  • Increased risk of retinal tears, lattice degeneration, peripheral degeneration, and retinal detachment. Annual dilated BIO with scleral indentation recommended.
  • Myopic maculopathy: Posterior staphyloma, lacquer cracks (Bruch's membrane rupture), Fuchs' spot (pigmentation at fovea post-CNV), chorioretinal atrophy, myopic foveoschisis, macular hole.
  • Tilted disc: Common in myopia. May mimic pallor or RNFL defect. Correlate with OCT RNFL and visual fields.
  • Warn patients to seek immediate care for sudden increase in floaters, new flashes, or curtain/shadow in vision.

Elderly Patients

  • Higher prevalence of AMD, glaucoma, diabetic retinopathy, hypertensive retinopathy, and CRVO/BRVO. Dilated fundus examination at every comprehensive visit.
  • Smaller pupil (senile miosis) makes dilation even more important. May require combination tropicamide + phenylephrine for adequate dilation.
  • Carotid artery disease: Hollenhorst plaques (bright, glistening cholesterol emboli at arteriolar bifurcations) indicate atherosclerosis and cardiovascular risk. Urgent physician referral.
  • Monitor medications: hydroxychloroquine (antimalarial) causes bull's-eye maculopathy — annual OCT and Humphrey 10-2 fields required.

10. Troubleshooting Common Issues

Cannot Find the Optic Disc (Direct)

  • Locate a blood vessel and follow it in the direction of increasing vessel calibre — all vessels converge at the disc.
  • Ask patient to fixate slightly nasal to the light — the disc is approximately 15° temporal to the fovea.
  • Ensure you are approaching from the temporal side (~15° lateral to the patient's visual axis).
  • Check dioptre wheel — out-of-focus image makes the disc much harder to find. Adjust wheel until vessels are sharp.

Corneal Reflection Obscuring View (Direct)

  • Move slightly to one side to change the angle of incidence of the light, moving the reflection out of the viewing axis.
  • Get closer to the patient's eye — reduces reflection. Aim to be within 2–3 cm.
  • Use the small spot aperture in undilated patients.
  • A cobalt blue filter or polarising filter on some models reduces surface reflections.

Poor BIO Image Quality

  • Double image: IPD on headset incorrect. Readjust to match your own PD.
  • No fundus image: Lens not perpendicular to optical axis, or too far/close from cornea. Hold lens steady at focal length (~5–7 cm for +20D).
  • Blurred, unfocused image: Move your head slightly forward or backward (change object distance) rather than moving the lens to refocus.
  • Small or restricted view: Insufficient dilation. Allow more time or use phenylephrine in addition to tropicamide.
  • Patient squeezing: Reduce illumination intensity initially. Both eyes open. Topical anaesthetic for indentation procedures.

Difficulty Examining Through Dense Media Opacity

  • Increase illumination to maximum and use maximum pupil dilation.
  • For dense cataracts: document reduced view quality and reason. B-scan ultrasonography is preferred to assess posterior segment when media is opaque.
  • Red-free filter sometimes improves vessel contrast even through mild media haze.
  • Refer for ophthalmology assessment if adequate fundus view is not achievable and clinical indication exists.

11. Clinical Pearls and Best Practices

Clinical Pearl #1: Always Dilate

An undilated fundus examination is an incomplete fundus examination. The peripheral retina — where tears, lattice degeneration, and early detachments occur — is simply inaccessible without dilation and BIO. Every examination where posterior segment pathology is a concern requires dilation.

Clinical Pearl #2: Brückner Test in Every Child

The simultaneous red reflex (Brückner test) from 50 cm takes five seconds. A white reflex (leukocoria) in a child must exclude retinoblastoma until proven otherwise. Asymmetry detects strabismus and significant anisometropia. Never skip it in paediatric patients.

Clinical Pearl #3: Follow the Vessels to the Disc

When performing direct ophthalmoscopy and the disc is not immediately visible, find any blood vessel and follow it towards increasing calibre. All retinal vessels converge at the optic disc. This simple manoeuvre reliably guides you to the disc every time.

Clinical Pearl #4: Vertical CDR Matters Most

Always measure the vertical cup-to-disc ratio, not the horizontal. Glaucomatous damage preferentially affects the superior and inferior neuroretinal rim (ISNT rule). A CDR of 0.7 horizontally may be normal, but 0.7 vertically with inferior notching is not. The vertical dimension catches more pathology.

Clinical Pearl #5: Red-Free Filter for Haemorrhages

The green (red-free) filter dramatically enhances the visibility of haemorrhages, nerve fibre layer defects, and blood vessel detail. Any time haemorrhage or RNFL loss is suspected, switch to the red-free filter before concluding the examination. It takes two seconds and reveals far more.

Clinical Pearl #6: Asymmetry is the Key Warning Sign

Always compare findings between the two eyes. Asymmetric CDR (>0.2), asymmetric disc pallor, asymmetric RNFL, and asymmetric vascular calibre are often more diagnostically significant than absolute values. The fellow eye is the best control you have.

Clinical Pearl #7: Document the Disc Haemorrhage

A disc haemorrhage is transient — it resolves within weeks. If found, photograph and document it immediately. It is one of the strongest indicators of active glaucomatous nerve fibre loss. A missed or undocumented disc haemorrhage represents a missed opportunity for early intervention.

Clinical Pearl #8: Flashes + Floaters = Dilated BIO

A patient presenting with new onset flashes and floaters must receive a dilated BIO examination with scleral indentation at the same visit. Posterior vitreous detachment (PVD) is the most common cause, but retinal tears occur in 10–15% of symptomatic PVD cases and require urgent treatment.

Clinical Pearl #9: Papilloedema Until Proven Otherwise

Bilateral disc swelling must be assumed to be papilloedema from raised intracranial pressure until proven otherwise. Do not reassure the patient that it is a "normal variant." Same-day emergency referral is required. Unilateral disc swelling may be optic neuritis or NAION — also requires urgent assessment.

Clinical Pearl #10: BIO + Indentation for Every High Myope

Patients with high myopia (>−6.00D) are at significantly elevated risk of peripheral retinal degeneration and detachment. A routine posterior pole view is insufficient. Annual dilated BIO with scleral indentation is the standard of care for this population, regardless of symptoms.

Golden Rule of Ophthalmoscopy

"The fundus examination is not complete until you have examined the peripheral retina."The posterior pole visible with direct ophthalmoscopy represents only a small fraction of the total retinal surface. Mastery of BIO and scleral indentation is not optional — it is the defining skill that separates a comprehensive optometric examination from an incomplete one. The peripheral retina does not announce its pathology. You have to go and find it.

Quick Reference Protocol

  1. Prepare instruments: Verify illumination, lens cleanliness, and ophthalmoscope/BIO setup before examination.
  2. Complete pre-dilation checks: Perform van Herick assessment, confirm allergy history, and counsel regarding post-dilation safety.
  3. Dilate when indicated: Instil standard mydriatic agents and confirm adequate pupil size for peripheral retinal assessment.
  4. Perform direct ophthalmoscopy: Assess red reflex, optic disc, posterior pole, and macula with systematic focusing and sequence.
  5. Perform BIO examination: Assess posterior pole and peripheral retina with inversion awareness and scleral indentation where required.
  6. Use systematic sequence: Examine optic disc, vasculature, macula, and periphery in a consistent order to avoid missed findings.
  7. Classify and triage findings: Correlate diabetic, hypertensive, AMD, glaucomatous, and peripheral retinal signs with urgency criteria.
  8. Document comprehensively: Record lesion location, grading details, dilation status, and referral/follow-up plan.

Documentation and Communication

Essential Clinical Documentation

  • Document optic disc findings including vertical CDR, rim colour, margin appearance, disc haemorrhage, disc size, and NVD status.
  • Document vessel findings including A:V ratio, AV crossing changes, calibre, haemorrhage type/location, exudates, and NVE.
  • Document macular findings including foveal reflex, drusen characteristics, pigmentary change, oedema, membrane, and haemorrhage.
  • Document peripheral findings including lattice degeneration, tears, naevi characteristics, and other peripheral retinal changes.
  • Record media clarity, dilation agent/concentration/time, pupil size achieved, and whether view was limited.
  • Use clock-hour and disc-diameter localisation; include fundus drawing/photography where available for baseline monitoring.

Patient and Family Communication

  • Explain dilation effects, temporary blur/light sensitivity, and transport safety advice before discharge.
  • Counsel on urgent symptoms requiring immediate care, including sudden flashes, floaters, curtain/shadow, or acute visual loss.
  • Discuss condition-specific risk and monitoring intervals for diabetes, high myopia, AMD risk, and glaucoma progression signs.
  • Provide clear referral urgency when emergency criteria are present and document that communication explicitly.
  • Reinforce follow-up expectations and the rationale for serial retinal imaging and repeat dilated examination.

References

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  20. Royal Australian and New Zealand College of Ophthalmologists (RANZCO). Referral pathways for diabetic retinopathy and diabetic macular oedema. Sydney: RANZCO; 2021.