Unit 5: Clinical Examination of the Visual System | 3rd Semester of Bachelor of Optometry

ROPLAS (Regurgitation on Pressure over the Lacrimal Sac Area)

Introduction:

ROPLAS, short for Regurgitation on Pressure over the Lacrimal Sac area, is a simple, non-invasive clinical test performed to assess the patency of the nasolacrimal duct and to detect obstruction of the lacrimal drainage system. It is one of the most important tests in the examination of patients presenting with complaints of epiphora (watering of the eyes).

The test is based on applying gentle digital pressure over the lacrimal sac region and observing whether fluid or discharge regurgitates through the puncta. The nature of regurgitated material (clear tears, mucoid fluid, or purulent discharge) helps identify the level and type of obstruction in the lacrimal drainage system.

Anatomical Background

Understanding the lacrimal drainage apparatus is essential to interpret ROPLAS correctly. The system includes:

• Puncta: Small openings on the upper and lower lid margins near the medial canthus.
• Canaliculi: Short channels (2 mm vertical, 8 mm horizontal) leading to the lacrimal sac.
• Lacrimal sac: Reservoir located in the lacrimal fossa, continuous with the nasolacrimal duct.
• Nasolacrimal duct: Drains tears into the inferior meatus of the nose.

Any obstruction along this pathway may lead to stagnation of tears, infection, and discharge.

Indications for ROPLAS

• Patient complains of watering eyes (epiphora).
• Recurrent mucopurulent discharge.
• Swelling in the lacrimal sac region.
• Pre-operative evaluation for intraocular surgeries (e.g., cataract) to rule out dacryocystitis.
• Follow-up after lacrimal surgery (DCR or DCT).

Contraindications

• Acute dacryocystitis (applying pressure may worsen infection or cause cellulitis).
• Recent lacrimal or nasal surgery (risk of wound dehiscence).
• Orbital cellulitis (pressure may spread infection).

Procedure

1. Seat the patient comfortably, explaining the test to reduce anxiety.
2. Ask the patient to look up and slightly outwards.
3. Use index finger to apply gentle but firm pressure over the lacrimal sac area (just below the medial canthal tendon, at the inferomedial canthus).
4. Observe the puncta of both lids for regurgitation.
5. Note the quantity and quality of fluid expressed.

Interpretation of Results

• Positive ROPLAS: Regurgitation of fluid/discharge from puncta on applying pressure.
• Negative ROPLAS: No regurgitation despite symptoms; suggests partial block or functional epiphora.

Nature of Discharge and Clinical Implications

• Clear watery fluid: Suggests partial block or functional epiphora.
• Mucoid discharge: Suggests chronic dacryocystitis.
• Purulent discharge: Indicates infected sac with stasis of pus.
• Bloody discharge: May indicate trauma, tumor, or ulceration in sac.

Clinical Significance

ROPLAS is highly useful in:

• Diagnosing chronic dacryocystitis, the most common cause of watering.
• Differentiating epiphora due to obstruction from reflex tearing due to ocular surface disease.
• Preventing postoperative endophthalmitis: Positive ROPLAS is a contraindication for intraocular surgery until treated.
• Guiding further investigations like syringing, probing, or dacryocystography.

Differential Diagnosis of Epiphora

Epiphora may occur due to causes other than nasolacrimal duct obstruction, hence ROPLAS helps in differential diagnosis:

• Lacrimal drainage obstruction: Positive ROPLAS.
• Hypersecretion: Reflex tearing due to conjunctivitis, dry eye, keratitis (ROPLAS negative).
• Eyelid malposition: Ectropion or entropion affecting punctal apposition (ROPLAS negative).
• Neurological causes: Facial nerve palsy affecting lacrimal pump (ROPLAS negative).

Advantages

• Simple, quick, and non-invasive.
• No equipment required.
• Provides immediate clinical information.
• Highly useful in outpatient and screening settings.

Limitations

• Not quantitative; cannot measure exact site or severity of obstruction.
• May be negative in partial or functional blocks despite symptoms.
• False negatives possible in fibrosed or shrunken lacrimal sacs.
• Further tests (syringing, dacryoscintigraphy, or imaging) may be required for confirmation.

Comparison with Other Lacrimal Tests

Test	Principle	Use
ROPLAS	Regurgitation on pressure over sac	Simple screening for obstruction
Syringing	Instillation of saline via puncta	Confirms patency and level of block
Dacryocystography	Radiographic imaging with contrast	Defines anatomical site of obstruction
Dacryoscintigraphy	Radioisotope-based	Evaluates physiological tear drainage

Amsler Grid Test

Introduction:

The Amsler grid test is a simple, inexpensive, and widely used clinical tool to assess the central 10 degrees of the visual field. It is primarily employed to evaluate macular function and to detect early changes in the central retina and visual pathway. The test consists of a grid of horizontal and vertical lines with a central fixation point. Patients with macular disease may perceive distortions, missing areas, or scotomas on the grid.

Despite the availability of advanced imaging such as optical coherence tomography (OCT), the Amsler grid remains an essential clinical and home-based monitoring tool. It is especially valuable for detecting early macular changes in conditions such as age-related macular degeneration (AMD), diabetic maculopathy, and toxic retinopathies.

History

The test was introduced by Swiss ophthalmologist Marc Amsler in the 1940s. Its simplicity, portability, and effectiveness made it one of the most popular macular function tests in both clinics and patient self-monitoring.

Principle

The Amsler grid test is based on the principle that disturbances in the macula and central retina affect the patient’s perception of straight lines, fixation, and uniformity of the grid pattern.

Normal macula: Straight, evenly spaced lines with no distortions. Macular pathology: Distorted (metamorphopsia), blurred, or missing areas (scotomas) in the grid.

Design of the Amsler Grid

• Square grid with evenly spaced vertical and horizontal lines.
• Usually 10 cm × 10 cm with central fixation dot.
• When viewed at 30–35 cm, each square represents approximately 1 degree of the visual field.
• Variations include white grid on black background, red grid on black background, or diagonal lines.

Objectives

• To evaluate the central visual field (10 degrees around fixation).
• To detect metamorphopsia (line distortion).
• To identify central or paracentral scotomas.
• To monitor progression of macular diseases.
• To serve as a home-monitoring tool for early detection of changes.

Procedure

1. Test is performed monocularly; one eye is occluded while the other is tested.
2. Patient wears near correction if required.
3. Hold the Amsler grid at 30–35 cm under good illumination.
4. Ask the patient to fixate steadily on the central dot.
5. Instruct the patient to describe what they see:
   • Are all four corners visible?
   • Are the lines straight or wavy?
   • Are any areas missing, blurred, or distorted?
6. Repeat for the other eye.

Interpretation of Results

Normal result: Patient perceives grid as uniform with straight lines, no missing areas.

Abnormal results:

• Metamorphopsia: Distortion of lines (common in macular edema, AMD, epiretinal membrane).
• Scotoma: Missing or dark areas (central in macular degeneration, paracentral in diabetic maculopathy).
• Micropsia/macropsia: Lines appear smaller or larger than normal (common in retinal traction).
• Blurred areas: Indicate reduced central sensitivity (seen in macular dystrophies).

Clinical Applications

• Age-related macular degeneration (AMD): Detects early distortion and scotomas before severe vision loss.
• Diabetic macular edema: Identifies localized swelling causing distortion.
• Central serous chorioretinopathy (CSR): Detects central scotomas or distortions.
• Macular hole: Reveals central dark spot.
• Drug toxicity: Hydroxychloroquine retinopathy produces paracentral scotomas.
• Other macular disorders: Epiretinal membrane, macular dystrophies.

Variations of Amsler Grid

• Standard black-on-white grid: Most commonly used.
• White-on-black grid: Improves contrast sensitivity testing.
• Red grid on black background: Detects subtle red desaturation in optic nerve disease.
• Diagonal line version: Used in patients with poor fixation to maintain attention.

Advantages

• Simple, quick, inexpensive.
• Requires minimal equipment.
• Detects subtle macular pathology before fundus changes are visible.
• Useful for patient self-monitoring at home.

Limitations

• Subjective, depends on patient’s description.
• Not quantitative; does not grade severity.
• Less reliable in children or uncooperative patients.
• Cannot detect peripheral retinal disease (limited to central 10°).
• Advanced OCT and perimetry are more sensitive for early detection.

Comparison with Other Macular Function Tests

• Photostress Recovery Test: Evaluates macular photoreceptor function (recovery time after bleaching).
• Foveal threshold perimetry: Quantifies central retinal sensitivity using automated perimeters.
• Multifocal ERG: Provides objective measurement of macular electrical activity.
• OCT: Provides high-resolution structural imaging, not functional.
• Amsler grid: Quick, subjective, functional test for central vision integrity.

Contrast Sensitivity Function Test

Introduction:

The Contrast Sensitivity Function (CSF) test is an advanced clinical assessment that measures the ability of the visual system to detect differences in luminance (contrast) between an object and its background. While standard visual acuity charts such as Snellen or LogMAR measure vision under high-contrast conditions (black letters on white background), contrast sensitivity evaluates vision in real-world, low-contrast environments.

Many patients with ocular or neurological disease may show normal visual acuity but complain of poor vision in dim light, fog, or glare conditions. In such cases, contrast sensitivity testing provides valuable diagnostic information, often detecting functional visual loss earlier than conventional acuity charts.

Physiology of Contrast Sensitivity

Human vision depends on both spatial resolution (ability to see fine detail) and contrast detection (ability to detect differences in brightness).

• Spatial frequency: Refers to the size of visual detail, expressed in cycles per degree (cpd).
• High spatial frequencies: Represent fine details (letters, small objects).
• Low spatial frequencies: Represent large objects, outlines, and shapes.

The contrast sensitivity function curve is typically an inverted "U-shape": - Poor at very low and very high spatial frequencies. - Best at mid-spatial frequencies (3–6 cpd).

Principle of Contrast Sensitivity Testing

The test presents stimuli of varying contrast and spatial frequencies. The patient’s ability to detect or identify the stimulus is recorded. By measuring thresholds across frequencies, a contrast sensitivity function curve is plotted, providing a complete picture of visual performance.

Indications

• Patients with visual complaints despite normal Snellen acuity.
• Screening and monitoring ocular diseases (glaucoma, cataract, AMD).
• Assessment of amblyopia and pediatric visual function.
• Pre- and post-operative evaluation in refractive or cataract surgery.
• Assessment of visual disability in occupational settings (pilots, drivers).

Methods of Measuring Contrast Sensitivity

1. Pelli–Robson Chart

• Most widely used clinical test.
• Consists of large letters of equal size but decreasing contrast in triplets.
• Patient reads letters until unable to identify at low contrast.
• Results recorded in log contrast sensitivity.

2. Vistech Chart

• Consists of sine-wave gratings of different spatial frequencies and contrasts arranged in rows and columns.
• Patient identifies orientation of gratings (vertical, left-tilted, right-tilted).
• Provides detailed contrast sensitivity function curve.

3. Cambridge Low-Contrast Gratings

• Patient shown gratings of decreasing contrast at fixed spatial frequency.
• Used in research and pediatric testing.

4. Sine-Wave Gratings (Laboratory method)

• Computer-generated gratings of varying spatial frequency and contrast.
• Provides precise CSF curve but less practical in routine clinics.

5. Digital and Portable Devices

• Tablets, laptops, and VR-based systems now provide CS testing with automated scoring.
• Useful for telemedicine and large-scale screening.

Interpretation of Results

• Normal curve: Inverted U-shape, peak at mid-spatial frequencies.
• Glaucoma: Reduced sensitivity at mid- and high-frequencies.
• Cataract: Uniform reduction across all spatial frequencies.
• AMD: Marked reduction at high frequencies affecting fine detail.
• Amblyopia: Reduced sensitivity, especially at mid- and high-frequencies.

Clinical Applications

• Glaucoma: Detects functional loss before field defects appear on perimetry.
• Cataract: Explains poor vision despite fair acuity; guides surgical timing.
• Diabetic retinopathy: Detects subtle macular dysfunction.
• AMD: Sensitive to early macular degeneration changes.
• Refractive surgery: Evaluates quality of vision after LASIK/PRK.
• Amblyopia: More sensitive than visual acuity in detecting residual deficits.
• Occupational vision: Pilots, drivers, military require good contrast sensitivity in low-visibility conditions.

Advantages

• Detects visual impairment not seen on standard acuity charts.
• Useful for early diagnosis of ocular diseases.
• Correlates better with real-world visual performance.
• Simple and quick (especially Pelli–Robson).

Limitations

• Results influenced by lighting, patient cooperation, and fatigue.
• Not standardized across all test types.
• Charts require proper calibration and distance.
• Less widely available than Snellen or LogMAR charts in routine clinics.

Comparison with Visual Acuity

• Visual acuity: Measures smallest high-contrast detail; may be normal in early disease.
• Contrast sensitivity: Detects reduced function under real-world, low-contrast conditions.
• Complementary role: Both should be tested for complete visual function assessment.

Saccades and Pursuit Test

Introduction:

Normal vision requires not only clear optical quality but also accurate and well-coordinated eye movements. Two of the most important ocular motor functions are saccades and smooth pursuit movements. These eye movements ensure that objects of interest are rapidly acquired and steadily tracked on the fovea for clear perception.

The Saccades and Pursuit Test is a clinical evaluation of these two systems. It assesses the speed, accuracy, initiation, and coordination of saccadic eye movements and the smoothness and gain of pursuit eye movements. It is particularly useful in diagnosing neurological, vestibular, and ocular motor disorders.

Physiology of Eye Movements

Eye movements are controlled by six extraocular muscles, three pairs acting in agonist–antagonist relationships. They are coordinated by supranuclear centers in the brainstem and cerebellum.

• Saccades: Rapid, ballistic eye movements that bring the image of a new object onto the fovea.
• Pursuits: Slow, continuous eye movements that maintain fixation on a moving object.

Neural Control

• Saccades are generated by the frontal eye fields, parietal cortex, and brainstem burst neurons.
• Pursuits are controlled by occipital visual areas, cerebellum, and vestibular nuclei.

Principle of the Test

By presenting fixed and moving visual targets, the examiner can evaluate the efficiency of the patient’s saccadic and pursuit systems. Abnormalities may suggest ocular motor dysfunction, neurological disease, or vestibular imbalance.

Indications

• Patients with complaints of reading difficulty, blurred vision, or losing place in text.
• Dizziness, vertigo, or balance problems (vestibular involvement).
• Neurological disorders (Parkinson’s, multiple sclerosis, stroke).
• Ocular motor nerve palsies.
• Pediatric assessment of binocular vision and learning-related eye movements.

Procedure for Testing Saccades

1. Patient is seated upright, instructed to keep head still.
2. Examiner holds two fixation targets (e.g., penlights, fingers) about 30 cm apart horizontally.
3. Patient is asked to shift gaze quickly from one target to the other upon command.
4. Test repeated vertically and diagonally.
5. Examiner observes initiation, speed, accuracy, and overshoot/undershoot of eye movements.

Parameters Assessed

• Latency: Time taken to initiate saccade (normal ~200 ms).
• Velocity: Speed of movement (can exceed 500°/sec).
• Accuracy: Eyes should land precisely on target.
• Dysmetria: Overshoot (hypermetria) or undershoot (hypometria).

Procedure for Testing Pursuits

1. Patient fixates on a slowly moving target (penlight/finger).
2. Target moved horizontally, vertically, and in circular pattern at ~20°/sec.
3. Patient asked to follow target smoothly without moving head.
4. Examiner observes smoothness, continuity, and ability to maintain fixation.

Parameters Assessed

• Gain: Ratio of eye velocity to target velocity (ideally 1.0).
• Smoothness: Movements should be continuous, not jerky.
• Catch-up saccades: Indicate poor pursuit when eyes fall behind target.

Interpretation of Findings

Normal

• Saccades: Rapid, accurate, minimal latency.
• Pursuits: Smooth, continuous tracking without catch-up movements.

Abnormal

• Saccadic intrusions: Unstable fixation, seen in cerebellar disease.
• Slow saccades: Internuclear ophthalmoplegia, myasthenia gravis.
• Dysmetric saccades: Overshoot/undershoot in cerebellar dysfunction.
• Poor pursuits: Jerky, broken tracking, common in parietal/occipital lesions.

Clinical Applications

• Glaucoma and amblyopia: Abnormal pursuits may explain reading difficulty.
• Neuro-ophthalmology: Localizing lesions in brainstem, cerebellum, or cortex.
• Vestibular testing: Pursuit abnormalities suggest central vestibular disorder.
• Learning disabilities: Poor saccades linked to reading disorders in children.
• Parkinson’s disease: Hypometric saccades and impaired pursuit.

Advantages

• Simple, quick, non-invasive bedside test.
• Requires no equipment beyond small fixation targets.
• Provides valuable diagnostic and localizing neurological information.

Limitations

• Qualitative; does not provide precise quantitative measures.
• Requires patient cooperation.
• Subtle abnormalities may need advanced eye-tracking systems (infrared oculography, video-based testing).

Advanced Methods

• Infrared oculography: Quantitative recording of eye movements.
• Electrooculography: Records corneo-retinal potential changes with movement.
• Video-oculography: High-resolution recording of saccades and pursuits.

Comparison of Saccades vs Pursuits

Feature	Saccades	Pursuits
Type	Rapid, ballistic	Slow, continuous
Purpose	Acquire new target	Maintain fixation on moving target
Speed	Fast (up to 500°/sec)	Slow (~20–40°/sec)
Control	Frontal eye fields, brainstem	Occipital lobe, cerebellum
Common Disorders	Hypometric in Parkinson’s, slow in INO	Jerky in central vestibular lesions

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For more units of Clinical Examination of the Visual System click below 👇 

✅Unit 1

✅Unit 2

✅Unit 3

✅Unit 4