Visual Fields & Macula - OPT505 Lecture 13 PDF

Attendance code: Attendance code: OPT505 Lecture 13:Visual fields & the macula Ellie Livings Learning outcomes Compare and contrast the available range of methods used for assessing the macula such as the visual field analysers, photo stress recovery time and Amsler grid Instruct a patien...

Attendance code: Attendance code: OPT505 Lecture 13:Visual fields & the macula Ellie Livings Learning outcomes Compare and contrast the available range of methods used for assessing the macula such as the visual field analysers, photo stress recovery time and Amsler grid Instruct a patient on the appropriate use of an Amsler grid and interpret the results given Understand difference in central fields versus other test patterns Recap of retina How does the macula differ from the rest of the retina anatomically and functionally? What is the effect of glare on macular function? Foveola (0.2mm or ~1°) Fovea: (1.5 mm or ~5°) Highest photoreceptor density 150,000 cones (high VA) Thinned depressed area Avascular Macula (5.5 mm or ~18°) When do we do a macular assessment? Symptoms: if during the H&S, the patient complains of: – Central visual disturbance or metamorphopsia – Micropsia – Macropsia – Colour vision changes *Read about Uhthoffs and Pulfrich phenomena Clinical findings: if during the eye examination, you find: – Unexplained visual acuity loss (large change from LEE) that does not improve with pinhole – Symptoms that cannot be explained after the health and fundus assessment – Unable to read small print with best correction – Abnormal appearance of the macula (macular or ARMD changes) or optic nerve with ophthalmoscopy – Abnormal colour vision Causes of macular dysfunction Macular pathologies (macular hole, CME, ARMD, Diabetic retinopathy, retinal vascular disease, epiretinal membrane…) Amblyopia Neurological (optic neuritis, hemianopia, pituitary gland tumor,…) Toxicity from drugs Advanced glaucoma damage Retinal detachment … Which test to use to assess the macula function and its anatomical integrity? Amsler grid Pupil assessment Central Automated visual Slit lamp BIO fields analysis (10-2) Microperimetry MPS II Photo stress recovery time Preferential hyperacuity perimeter Visual acuity: Dark adaptometers Contrast Sensitivity OCT Fluorescein angiogram (FFA) Colour vision (Ishihara plates) BCVA Simplest way to detect macula pathology May vary distance/near Offers limited insight into small/extra foveal areas of damage Subclinical presentation of pathology often does not cause reduced VA (or reported symptoms) May be affected by other pathology e.g. cataract Use of pin-hole: implies macula pathology Fundus imaging Macula 5.5mm diameter Fovea  Red-free filter Is a green filter used to enhance contrast Green light absorbed by blood but partially reflected by retinal pigmentation. Media opacities not quite so troublesome (less scatter) Enhances view of retinal vasculature, drusen and exudates Fluorescein angiography Uses intra-venous fluorescein and sequential (black & white) photos Shows how blood moves through retinal circulation Shows area of leakage and non- profusion Requires px to not eat/drink for 6-8 hours prior Can cause serious allergic reactions https://www.eophtha.com/posts/fundus-fluorescein- angiography-and-indocyanine-green-angiography-made-easy- for-the-postgraduates Amsler grid: Central 20o Held at 30cm Each square = 5mm = 1 degree Central 20o measured Reading Rx worn Monocular Room lights on Get px to draw defect Central absolute scotoma Arcuate defect Absolute paracentral scotoma Macropisa Micropisa Metamorphopsia Amsler Grid PROS CONS Quick Compliance generally poor Cheap Lacks sensitivity Portable Can be misunderstood by px Easy Results not diagnostic or predictive of treatment/referral Amsler Not so useful as ‘in house’ or diagnostic tool Can be useful to help px map out area of functional difficulty Can give to px to take home for ‘self-monitoring’ Can be psychologically nice for px to feel they have something to do May be useful in encouraging px to return if symptoms worsen-speedier treatment Make sure px puts it somewhere obvious: Not in a drawer!  NA-UP-JR Suprathreshold test: 40 points over C40 central 30° Useful for screening where no defect suspected (baseline normal) Threshold test (SITA algorithm) More data-tests 54 points over central 24° (out to 30° nasally) Sita 24-2 points 6° apart Grid of points straddles midlines: nasal step/hemianopia Only 12 points withing 10° of fixation Central 10-2 test Automated visual field analyser Useful: – for differential diagnosis of symptoms – for monitoring for adverse ocular effects of systemic medication e.g. hydroxycholorquine – for monitoring advance glaucoma changes -monitoring early parafoveal scotomas in conjunction with SITA 24-2  NA-UP-JR 10-2 test Pattern design Central Full threshold test (central 10°) Spatial resolution of at least 2° Measures 68 points Central 10-2 v Sita 24-2 glaucomatous parafoveal NA-UP-JR scotomas Table 2. Progression Rates and Number of Sigificantly Progressing Points in 10-2 and 24-2 Visual Field Analyses Characterist 10-2 Visual 24-2 Visual 24-2 Visual P Value∗ P Value† ics Field Field Field within Central 10° Global −0.40±0.51 −0.23±0.28 −0.32±0.47 0.015 0.313 progression (−1.53 to (−1.00 to (−1.99 to rate (dB/yr)‡ 1.09) 0.35) 0.64) Localized −2.72±1.42 −2.48±1.13 −3.61±1.37 N/A N/A progression (–6.99 to (−4.84 to (−4.88 to rate (dB/yr)‡ −1.02)§ −1.02)⋮ −1.67)¶ Number of 5.2±4.9 (1– 2.8±3.2 (1– 2.3±1.0 (1– N/A N/A significantly 20) 12) 3) progressing VF test points‡ # Sung et al. (2013) Parafoveal Scotoma Progression in Glaucoma: Humphrey 10-2 versus 24-2 Visual Field Analysis, Ophthalmology,Vol. 120, Issue 8,Pp. 1546-1550 LE RE Drugs which can affect the macula drug use Colour defect Alcohol R/G Aspirin R/G Hydroxychloroquine Anti-rheumatic/anti- B/Y malarial Ethambutol Anti-tuberculosis R/G digoxin Heart meds B/Y indomethacin NSAID B/Y Thioridazine antipsychotic B/Y OCT Nice OCT images and explanation of different drusen and macula appearance: https://en.octclub.org/yasa-bagli-makula-dejenerasyonu/ https://eyeguru.org/essentials/interpreting-octs/ OCT AMD Macular pigment screener MPS II Can detect early stages of ARMD It measures macular pigment (MP) density calculated by measuring blue light absorption by the macular pigment It uses Heterochromatic Flicker Photometry (HFP): compares the flicker perception of blue/green light between the fovea (MP present) and the periphery (no MP) and calculates the MP density (vary luminance blue/green ratio until patients sees a flicker) The MPS II uses age-matched normative data for the periphery, so only central measurements are needed →if low MP density, more probability of developing ARMD (Haegerstrom- Portnoy, 1988; Weiter et al., 1988). Preferential Hyperacuity Perimeter (PHP) Because of “filling in” mechanism in the brain, the patient may not be aware of subtle changes or distortions in the vision at early stages of AMD (wet AMD) PHP measures early functional changes in the macula Measures central 14 degrees To detect anomalies, it uses Vernier acuity (hyperacuity), which measures the degree of misalignment of lines or dots, and visual attention between artificially distorted lines and pathologically distorted lines Microperimetry Microperimetry examination of the macula is a tool to assess the retinal sensitivity and the fixation behaviour in patients with macular diseases. Results overlayed onto retinal image Allows for direct mapping of stimulus in the region of interest Correlates functional information with structural information Adds useful information, but standard automated perimetry remains gold standard in glaucoma care Ongoing research to use MP examinations as functional endpoint for future clinical trials and to interpret follow up examinations in everyday clinical use. Scuderi, L., Gattazzo, I., de Paula, A. et al. Understanding the role of microperimetry in glaucoma. Int Ophthalmol 42, 2289–2301 (2022). Coulibaly, L.M., Mohamed, H., Fuchs, P. et al. Inter and intradevice assessment of microperimetry testing in aging eyes. Sci Rep 14, 1049 (2024). Other hyperacuity based tests Shape discrimination is affected in AMD Mobile-phone application used in USA to self-monitor any change from the maculopathy (Wang and Bedell, 2014, Wang et al., 2013) Photo stress recovery time (PSRT) Bleaching of the photoreceptor visual pigments light stress Regeneration of photopigment delayed or longer in Pxs with macular disease PSRT – what do the results mean? Delayed photo stress recovery time PSRT pinpoints pathology arising from the macula (retinal). If normal PSRT then pathology may be due to the optic media or optic nerve Lack of standardisation Dark Adaptometers: measure rod function In AMD, there is parafoveal rod loss and dysfunction (Curcio, 2001) Dark adaptometers can measure the recovery time to a certain level (horizontal line in the figure) of the rod function after bleaching the eye Patients with early AMD, RP or maculopathies affecting rods will need more time for the rod recovery AdaptDx Pro® is the only test for dark adaptation that can be used quickly and effectively in a clinical setting. It uses an objective functional measure called the Rod Intercept® (RI®). Unlike traditional dark adaptation testing, the AdaptDx Pro Rapid Test takes less than 6.5 minutes. Easy to administer and interpret, it is reimbursable and detects AMD with 90.6% accuracy.ii Nigalye AK, Hess K, Pundlik SJ, Jeffrey BG, Cukras CA, Husain D. Dark Adaptation and Its Role in Age-Related Macular Degeneration. J Clin Med. 2022 Mar 1;11(5):1358. The future………. AI models to predict progression from dry to treatable wet. Using data from AREDs study , iPredict system can be used to take a retinal photo plus other details e.g. age, gender etc. Algorithm predicts likelihood of progression. In the AREDS dataset, iPredict predicted 2-year risk for progression to late AMD with 86% accuracy. Bhuiyan, A., et al., Artificial Intelligence to Stratify Severity of Age-Related Macular Degeneration (AMD) and Predict Risk of Progression to Late AMD. Translational Vision Science & Technology, 2020. 9(2): p. 25-25. https://www.nei.nih.gov/about/news-and-events/news/ai-based-systems-can-help-identify- rapidly-advancing-age-related-macular-degeneration Recommended reading Grosvenor, T. (2007) Primary Care Optometry. 5th edn. St Louis, Mo: Butterworth-Heinemann/Elsevier. Rosenfield, M. & Logan, N. (2009) Optometry: Science, Techniques and Clinical Management. 2nd edn. London: Butterworth- Heinemann/Elsevier Elliot, D.B. (2014) Clinical Procedures in Primary Eye Care. 4th edn. Philadelphia: Saunders/Elsevier. Doshi, S. & Harvey, W. (2003) Investigative techniques and ocular examination. Edinburgh: Butterworth-Heinemann/Optician.  Attendance code: Visual fields decision tree Overall Decision Tree for Basic Field Choice: New advice is to consider fields on people under 35, Must always consider your own professional judgement: Which field is most appropriate? Don’t do unnecessary tests on people: ‘’7.6 Only provide or recommend examinations, treatments, drugs or optical devices if these are clinically justified, and in the best interests of the patient.’’ GOC Standards of Practice for Optometrists and Dispensing Opticians 2016 https://optical.org/media/201flx0e/standards_of_practice_for_optoms_dos.pdf If there’s FHG the px is at a theoretically increased risk of developing glaucoma themselves wrt population risk: Parent with glaucoma=2x risk Sibling with glaucoma =8x risk H&S: who has it—ask about extended members, ask about tx, age of onset *you are still screening, but screening with a higher sensitivity: Sita 24-2—also baseline data. Put results together with ONH /OCT/IOP/Angles etc https://cks.nice.org.uk/topics/glaucoma/background-information/risk- factors/#:~:text=Family%20history%20and%20genetic%20factors,risk%20%5BBowling%2C%202015%5D.  Availability of local shared care schemes. And what they actually do In Plymouth, we have POCGS which is monitoring stable glaucoma. If they are in this, you don’t need to duplicate the data, BUT you can still get a field if the px is new to your practice, their IOP is high ( esp above their target) or if you see something new/they admit to not taking drops etc. HA, Missing things in fields, complaints of peripheral vision, recent stroke, long term stroke with no field on file. Head trauma, brain tumour…  Data must be useable. May not be physically or cognitively able to perform your ideal fields. * if it’s the best you & your px can manage, it’s the best option Adaptability—can you do it another day, when they’re less tired, after dispense, give them a cup of tea etc. Use the pause button on the field machine Px 1: Which field test? Age 45, first EE since childhood. No concerns from px No FHG Ocular exam unremarkable IOP 18T18 NCT @ 13:45 Px 2: Which field test? Age 45, Attends yearly, wears SVD for myopia (-7DS) No concerns from px No FHG CD ratio 0.6/0.65 IOP 22T22 NCT @ 13:45 Px 3: Which field test? Age 75, Attends yearly, IOL x2 Under HES for glaucoma, takes latanoprost nocte OU Last seen 1/12 ago Mum glaucoma @65 CD ratio 0.8/0.7 IOP 12A12 @ 13:45