OPT505 Lecture 12: Presbyopia & the Near Add PDF

Attendance code: Attendance code: Attendance code: OPT505 Lecture 12: Presbyopia & the Near Add Ellie Livings  Attendance code: Intended Learning Outcomes Understand the purpose, role and mechanism of accommodation Be able to clinical...

Attendance code: Attendance code: Attendance code: OPT505 Lecture 12: Presbyopia & the Near Add Ellie Livings  Attendance code: Intended Learning Outcomes Understand the purpose, role and mechanism of accommodation Be able to clinically assess accommodation in pre-presbyopic patients Determine the near ADD in presbyopes Ascertain the range of clear vision with a given ADD Presbyopia From birth we start to lose ability to accommodate (this is part of emmetropization up until about 10 years old) As we reach our 40’s the decline starts to affect our ability to see near objects (33cm – 40cm) For previous non-spectacle wearers, this is FRUSTATING!  Pre-Presbyopia DV lens Corrected for DV: Correcting lens puts blur circle on retina, DV is clear. ∞ Accommodated for N: More plus power to eye, blur circle on retina, DV is Near point blurred, near vision is. Requires effort++. Accommodative effort for near  Presbyopia DV lens Corrected for DV: Correcting lens puts blur circle on retina, DV is clear. ∞ Cannot Accommodate adequately for N: Near vision is blurred Accommodative effort for near  DV lens Corrected for DV: Correcting lens puts blur circle on retina, DV is clear. ∞ DV lens = ADD ADDitional plus places blur circle on retina for near BUT DV would now be blurry through this portion Crystalline lens and ageing Continues to grow throughout life Heavier and denser Stiffer Increased axial thickness but not equatorial diameter Optical properties change Refractive index changes Increase in positive spherical aberration Less light transmission Development of cataract Proteins degenerate  Presbyopia: loss of accommodation Figure 4. A 6-year-old monkey lens unstretched (A) and stretched (B) compared with a 46-year-old human lens unstretched (C) and stretched (D). https://crstodayeurope.com/articles/2016-oct/the-lens-as-time-goes-by/ Monocular amplitude of accommodation and age Based upon Hoffstetter formula (1944) Minimum Average Maximum Age 15.0 - 0.25*age 18.5 – 0.30*age 25.0 – 0.40*age 10 12.50 15.50 21.00 20 10.00 12.50 17.00 30 7.50 9.50 13.00 40 5.00 6.50 9.00 45 3.75 5.00 7.00 50 2.50 3.50 5.00 55 1.25 2.00 3.00 60 0.00 0.50 1.00 Note: these amplitudes include depth of focus On your diary for the day, you see the following note: New px, 47, no specs. C/o struggling to read and HA What’s your preliminary diagnosis? Presbyopia, probably low plus distance rx, needs first time general glasses, or possibly reading glasses  ‘’My arms aren’t long enough………’’ Print seems smaller/dimmer Struggle to maintain/change focus Vision worse in the evening/poor light Frontal HA, esp associated with near work Asthenopic symptoms Feeling current specs ‘aren’t strong enough’  Explaining presbyopia When we’re young, our This happens at a lens inside our eyes is You might have found it’s very predictable rate. clear and flexible. As we easier first thing in the I can look at your age get older, it gets less morning, or in good light- and what you’re flexible , so it takes more that’s because your lens trying to read and I effort to focus. That’s why muscles haven’t got tired know how much help you’re struggling to read yet. you need. things up close Imagine if you balled Glasses wont make your I’m actually really your fists for 10 mins eyes weak or lazy. Eyes pleased with your then tried to relax: it do not benefit from vision today, it’s would feel stiff. That’s exercise. Think of your looking great. You just like your eyes taking glasses like tools, they need a bit of help with longer to change focus help you do a job. focussing up close. when you look up from reading Managing Presbyopia refractively Not enough accommodation for near task Prescribe a near ADD Distance correction Need more plus to achieve working distance Sph Cyl Axis ADD RE +1.00 -0.25 90 +1.50 LE -0.50 -0.25 90 +1.50 Case Scenarios 1 What is the Near ADD? Distance Rx Sph Cyl Axis RE +2.75 -0.50 90 LE +3.25 -0.25 180 Near Rx Sph Cyl Axis RE +4.00 -0.50 90 LE +4.50 -0.25 180 Distance Rx Sph Cyl Axis Add RE +2.75 -0.50 90 (+4.00) - (+2.75) =+1.25 LE +4.50 -0.25 180 (+4.50) - (+3.25) = +1.25  Case Scenario 2 What is the Near Prescription? Distance Rx Sph Cyl Axis ADD RE +4.50 -0.50 90 +1.75 LE +3.25 -0.25 180 +1.75 +4.50+1.75 Near Rx Sph Cyl Axis RE +6.25 -0.50 90 LE +5.00 -0.25 180 So we want to give an Add, but how much? H&S reveals symptoms requiring Add Task analysis & Check range and Consider multiple Tentative Add WD comfort WD (int add) Consider what we will make up in glasses Tentative Add: Methods Methods to determine Add: -Age expected addition - Amplitude of accommodation - Dynamic retinoscopy - Negative and positive relative accommodation - Near duochrome - Binocular cross-cylinder All techniques give a result similar to final add. Age –expected method is most reliable wrt final add. Error is high due to variation in individual need. Antona, B., Barra, F., Barrio, A., Gutierrez, A., Piedrahita, E. and Martin, Y. (2008), Comparing methods of determining addition in presbyopes. Clinical and Experimental Optometry, 91: 313-318.  Av WD is 40cm = need 2.50D accommodation Age in Expected Half of Deficit in Tentative Add Presbyopia exists when AOA is < 5D years AoA (D) AoA Accom. @ 40cm (Morgan) 40 4.00 2.00 0.50 +0.50 Presbyopia reported when near point exceeds 45 3.50 1.75 0.75 +1.00 22cm (AoA =4.50D) (Donders) 50 2.50 1.25 1.25 +1.50 55 1.75 0.875 1.63 +2.00 60 1.00 0.50 2.00 +2.25 Either: Leave one-half of AOA in reserve (Lawrence and Maxwell) 65 0.50 0.25 2.25 +2.25 70 0.00 0 2.50 +2.50 Or: Leave one third of AoA in reserve IOL (Sheard and Giles) 0.00 0 2.50+ +2.50 Determine tentative add using amplitude of accommodation An individual can only comfortably exert 50% of the available AOA (Lawrence) or 2/3 of AOA (Sheard & Giles) Add = WD (D) – 1/2Amp (D) - Px aged 50yrs - Reads at 40cm = 2.50D required - Expected min. A0A = 2.50D - Tentative add = 2.50 – ½(2.50) = 1.25D Age in years Expected AoA Tentative Add Ellie’s Int Add @ (D) @ 40cm suggested Add 60cm (-0.75) 40 4.00 0.75 0.00 45 3.50 +1.00 +1.00 to +1.25 0.50 50 2.50 +1.50 +1.75 to +2.00 +0.75 to +1.00 55 1.75 +2.00 +2.00 +1.25 60 1.00 +2.25 +2.25 +1.50 65 0.50 +2.25 +2.25 +1.50 70 0.00 +2.50 +2.25 to +2.50 +1.50 pseudophakic 0.00 +2.50 +1.50 https://www.opticianonline.net/cpd-archive/30 Determining the final ADD After selecting the tentative Add, make sure it gives a clear range. As a rule of thumb: if they can read N5 to about 25cm and out to about 45 cm, this is a good range. Record the Add working distance in cm and the range. Don’t forget the intermediate Add Don’t over- plus(but take comfort, range, prev specs, pupils and age into account) Record acuity achieved Determining the final ADD Once a tentative ADD is determined, you need to refine this ‘estimated’ ADD with the ±0.25DS flippers presented binocularly IMPORTANT that you give most minus/least plus Record N-number of smallest letters read for RE & LE @ preferred working distance e.g. RE: N4 @ 40cm LE: N5 @ 40cm  Calculate range of clear vision Px aged 70 years Far point = 1 / ( WD (D) – 1/2 AOA(D) ) - Measured AoA = 1.00D Near point = 1 / ( WD (D) + 1/2 AOA(D) ) - Near add = 2.50D for WD of 40cm a) What is the closest point of the range of clear vision? Near point = 1 / (2.50 + ½(1.00)) = 1 / 3 = 0.33 = 33cm b) What is the farthest point of the range of clear vision? Far point = 1 / (2.50 – ½(1.00)) = 1 / 2 = 0.5 = 50cm Range of clear vision = 33cm – 50cm High add in IOL in one eye only low vision Other Adds? Special task: Children, Downs very close/far syndrome, WD Accommodative problems  QH-LS-QX What sort of glasses? Bifocals Varifocals Occupational Sep Pairs Existing wearer Most new Office workers Vari non-tols Vari non- tol presbyopes Presbyopes Anisometropia Prism control Existing wearer with v small dv Pathology Children BF upgrade? rx Close wd Some Additional pair requirement occupations + SVD vertigo Most manufacturers have a new wearer non-tol policy for first time varifocal wearers  QH-LS-QX Where am I looking?  QH-LS-QX Good, better, best? New wearer education is key Fitting is critical Suitable frames Previous ‘horror stories’  QH-LS-QX Lens quality: PX view  QH-LS-QX Occupationals/enhanced readers/office glasses Available in different degressions set from approx. 1- 4m Much wider near and intermediate wrt normal varifocals Smoother transition INT→ near NOT for driving Avoiding non-tols Compare proposed add to old one: is it Are you giving SV or multifocals? What definitely better? Show px type of lens? Check the px feels comfortable in it in VDU specific: think task analysis, the consulting room-range multiple screens? Height? For new pseudophakes, consider Have you given a large dv rx change? previous rx. and spec mag. H&S in presbyopia Establish what they do now in full Areas of difficulty Asthenopic symptoms? Barriers to correction Possible options PX preference Contact lenses Surgery? Additional Considerations Risk of pathology Need for ‘baselines’ IOP Fields OCT Driving DVLA standards Estermann Comfort Advice & Management Look at any DV alterations as well as near changes Consider BV situation Practicality Prognosis When to recommend varifocals/bifocals/occups Px 1: Mrs Jones 47, no current specs. Office worker, drives. RE +0.50/-0.5 x 90 6/6 Add +1.00DS N4 LE +0.25/-0.25 x 85 6/6 N4 Px 2: Mr King 65, Separate pairs (DV/IV) currently. Office worker, drives. Wife ‘hated’ varifocals. RE +1.50/-1.00 x 90 6/6 Add +2.25DS N4 LE +2.00/-0.75 x 85 6/6 N4 Px 3: Mr Harvey 55, DVs only, takes off to read. Primary school teacher, drives. RE -3.50/-0.50 x 90 6/6 Add +2.00DS N4 LE -3.00/-0.75 x 85 6/6 N4 Px 4: Judge Judy 64, unhappy with last specs, wants advice on best options. RE +0.75DS 6/6 Add +2.25DS N4 LE +0.75DS 6/6 N4 Practical on Thursday! MUST be on time MUST be in clinic dress WITH name badge MUST be prepared (have read the lab session) Background learning: Understand how accommodation functions in a pre-presbyopic eye Understand how accommodation declines with age and the associated normative values Think about what near add we might start with in various situations Read ch 4 pg 95-100 of Elliott’s primary Eye Care Read lab book session for presbyopic topic Further reading Keirl (2007) Clinical Optics and Refraction – Chapter 12 pages 124- 131 (very good for theoretical and practical principles) Benjamin, W.J. (2006) Borish’s Clinical Refraction. 2nd edn. St Louis, Mo: Butterworth- Heinemann/Elsevier. Elliot, D.B. (2014) Clinical Procedures in Primary Eye Care. 4th edn. Philadelphia: Saunders/Elsevier. 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 Tunnacliffe, A.H. (1993) An introduction to visual optics. 4th edn. Canterbury : Association of British Dispensing Opticians Rabbetts, R.B. (2007) Bennett and Rabbetts' Clinical visual optics. 4th edn. Edinburgh : Butterworth-Heinemann/Elsevier Attendance code: