AMD Diagnosis and Color Defects Quiz

Nut-Free Zones

• Images depict a "Stop Nut-Free Zone" sign, along with various foods, including nut butter, and a variety of nuts.

Lecture Recording

• The lecture is being recorded and will be available via Panopto.
• Comments or questions may appear on the recording.
• The lecturer can pause the recording if a questioner does not want their question recorded.

OPT505 Lecture 13: Visual Fields & the Macula

• The lecture covers the assessment of the macula.
• Methods of assessing the macula include visual field analysers, photo stress recovery time, and the Amsler grid.
• Students learn to instruct patients on using the Amsler grid and interpreting results.
• The lecture also analyzes central visual field versus other visual test patterns.

Recap of Retina

• The fovea and foveola are areas with the highest photoreceptor density.
• The macula, a 5.5 mm area, is important for central vision.
• Anatomical and functional differences of the macula from other parts of the retina are explored.
• The effect of glare on macular function is examined.

Macular Assessment

• A macular assessment is performed when symptoms like central visual disturbance, metamorphopsia, micropsia, macropsia, and color vision changes are present.
• Unexplained visual acuity loss, symptoms not explained by a health and fundus assessment, inability to read small print, or abnormal macula or optic nerve appearance during ophthalmoscopy warrants a macular assessment.

Causes of Macular Dysfunction

• Diabetic retinopathy, retinal vascular disease, epiretinal membrane, and macular hole are examples of macular pathologies.
• Other causes include amblyopia, optic neuritis, hemianopia, pituitary gland tumors, drug toxicity, advanced glaucoma damage, and retinal detachment.

Macula Function Assessment

• Tests used to assess macula function and integrity include the Amsler grid, central automated visual fields analysis, photo stress recovery time, visual acuity, contrast sensitivity, color vision, pupil assessment, slit lamp biomicroscopy, microperimetry, preferential hyperacuity perimeter, dark adaptometers, and OCT.
• Fluorescein angiography is used to view retinal circulation, leakage, and non-profusion.

BCVA (Best Corrected Visual Acuity) test

• BCVA is an easy way to detect macular pathology.
• It may not provide a clear picture for small areas of damage.
• Subclinical presentations of pathology may not lead to reduced VA.
• The use of a pinhole test may imply macula pathology.

Fundus Imaging

• Fundus imaging is used to visualize the macula and fovea.
• Images of the macula and fovea structures are shown, with labeling.

Red-Free Filter

• The red-free filter enhances contrast, helps with viewing retinal vasculature, drusen (small lipid deposits), and exudates.

Fluorescein Angiography

• Fluorescein angiography reveals the movement of blood through the retinal circulation, and it reveals areas of leakage and non-profusion.
• Patients shouldn't eat or drink for 6-8 hours before this test.
• It can result in allergic reactions.

Amsler Grid Test

• The Amsler grid examination is held 30cm away.
• Each square represents 1 degree, facilitating measurement of the central 20 degrees.
• The examination requires the patient to wear reading glasses and the room must be lit.
• The patient marks any defects in vision on the grid.

Amsler Grid (continued) Charts 2-7

• Visual representations of different grid patterns used in the Amsler Grid test are shown.
• The images exemplify central absolute scotoma, arcuate defects, absolute paracentral scotoma, macropsia, micropsia, and metamorphopsia.

Amsler Grid (continued) Different Visualization Issues

• Shows images of central absolute scotoma, arcuate defect, absolute paracentral scotoma, macropsia, micropsia, and metamorphopsia.

Pros of Amsler Grid

• Quick, affordable, portable, and easy to use.

Cons of Amsler Grid

• Patient compliance is typically poor.
• It has limited sensitivity.
• Results may be misconstrued by the patient or be not diagnostic.

Additional Amsler Grid Information

• The test can help patients map out functional areas of difficulty.
• The test may offer comfort and motivation.
• Patients may be encouraged to return for quicker treatment if symptoms worsen.
• The test should be placed visibly.

Suprathreshold Test C40 and Threshold Test Sita 24-2

• The C40 test (40 points over central 30 degrees) is helpful for baseline screening when no defects are suspected.
• The SITA algorithm assesses 54 points over central 24 degrees (to 30 degrees nasally).

Central 10-2 Test

• Automated visual field analysis is used for differential diagnosis of symptoms.
• It's used to monitor adverse ocular effects of systemic medications (e.g., hydroxychloroquine) and monitor advanced glaucoma changes.
• It is helpful with early stages of parafoveal scotomas.

10-2 vs Sita 24-2 tests

• Progression rates and significant points are shown in visual field analyses for 10-2 versus 24-2 tests.
• Data shows both 10-2 & 24-2 provide important functional information, but 24-2 has a wider field of view.

Drugs Affecting Macula

• Lists various drugs like alcohol, aspirin, hydroxychloroquine, ethambutol, digoxin, indomethacin, and thioridazine and how they may affect the macula, potentially causing color defects in patients.

OCT

• OCT images provide details of different drusen and macula appearances.
• Several links provide further information and visual aids for learning purposes.

OCT Imaging ( Vitreoretinal Interface and Inner Retinal Layers)

• The image describes the various inner retinal layers.

OCT Images (Normal, Dry AMD, Wet AMD)

• Shows different OCT images for normal eyes.
• Images are shown for dry and wet AMD.
• Normal and distorted visual images are shown.

Macular Pigment Screener MPS II

• This detects early AMD by measuring macular pigment density using blue light absorption.
• Heterochromatic Flicker Photometry comparison of blue and green light perceptions between the fovea and the periphery helps determine the density.
• The test uses age-matched normative data to determine the central MP measurements.

Preferential Hyperacuity Perimeter (PHP)

• The test assesses macular function at the early stages of AMD (wet AMD) by detecting anomalies in Vernier acuity (line misalignment) and visual attention.

Microperimetry

• Microperimetry assesses retinal sensitivity and fixation behavior related to macular disorders.
• It correlates functional information with structural information.
• The technique complements the standard automated perimetry of glaucoma care.
• It aids in future clinical trials and follow-up examinations.

Other Hyperacuity Based Tests

• Shape discrimination is affected by AMD.
• Mobile-phone applications might be used in the USA for self-monitoring of Maculopathy changes in patients.

Photo Stress Recovery Time (PSRT)

• Photo stress recovery time measures the regeneration time of photopigments within the photoreceptors after light stress.
• Delayed recovery times suggest macular disease.

PSRT- What Do the Results Mean?

• Delayed times reflect pathology from the macula (retina).
• Normal PSRT could involve optic media or optic nerve pathology.
• Variability in test results lack standardization.

Dark Adaptometers

• Dark Adaptometers are used to evaluate rod function.
• Rods may be impaired in early stages of AMD or related maculopathies, resulting in increased recovery times.

AdaptDx Pro

• AdaptDx Pro is a rapid test for evaluating dark adaptation.
• It's useful for clinical settings, providing an objective function measure, and reimbursable.

The Future........

• Models predict progression from dry AMD to wet AMD using AREDs data and a photo plus other details (age, gender).
• iPredict predicts a 2 year risk of AMD progression.

Recommended Reading List

• A list of books and articles related to primary care optometry, optometry science, techniques, and clinical management, clinical procedures in primary eye care, and investigative techniques and ocular examination.

Visual Fields Decision Tree

• Provides a flow chart of questions and paths to guide the decision-making process in choosing the appropriate visual field test for a patient. Decision tree determines the most suitable test based on patient specifics like age, previous testing status, glaucoma concerns, and other factors.

Test your knowledge on age-related macular degeneration (AMD) and the related color defects caused by various drugs. This quiz covers methodologies, technologies, and conditions associated with macular pigment density and rod function. Explore critical concepts and improve your understanding of AMD diagnosis.