Advances in assessing and managing vision impairment

Transcription

1 Advances in assessing and managing vision impairment John Grigg Associate Professor and Head Discipline of Ophthalmology Consultant Ophthalmologist Sydney Eye Hospital and The Children s Hospital at Westmead

2 Advances in: -clinical assessment to refine the diagnosis -guide visual prognosis -help direct the genetic investigations -monitor new therapies. 2

3 Wide field Retinal photography 200 degrees fovea posterior Normal poleretinal camera photo 50 degrees macula 3

4 Retinal dystrophies classic appearances Stargardt Cone-Rod Dystrophy Rod-Cone dystrophy - RP Achromatopsia Cone Dystrophy Lebers Congenital Amaurosis 4

5 Retinal Dystrophies clinically normal Stargardt Achromatopsia Cone-Rod Dystrophy Cone Dystrophy Rod-Cone dystrophy - RP Lebers Congenital Amaurosis

6 Assessing poor vision Provide clues as to which part of the eye may be affected History Visual Function - Visual function - Duration - Medications - Family History - Systemic problems - Hearing loss, - Renal disease - Neurologic disease - Metabolic disease Rod dysfunction: - Difficulty with night vision or peripheral vision - Can t see stars at night - Difficulty finding seat in movie theatre - Turns lights on around house all the time Cone dysfunction - Problems seeing details - Difficulty reading - Colour vision disturbance Adaptation - Trouble adjusting from bright outdoors to indoors

7 How do we investigate Examine structure and function of the retina Function - Visual acuity - Refraction will glasses help - Colour vision - Visual field testing - Electrophysiology Structure - Colour photographs - Optical coherence tomography (OCT) - Fundus autofluorescence - Fluorescein angiogram 7

8 Advances in Assessing Vision Optical coherence tomography (OCT) Fundus Autofluoresence Electrophysiology 8

9 Normal Macular appearance OCT & Histology

10 OCT angiography 10

11 Autofluorescence Natural re-emission of light by biological tissues after they have absorbed light RPE lipofuscin major source in retina - a by product of photoreceptor renewal Blue light (488nm) stimulates the tissues Images captured with scanning laser ophthalmoscopy 11

12 The retinal layers and the tests of their function To occipital cortex VEP Nerve fibre layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting Rods and cones Pigment epithelium ERG EOG

13 The Flash Electroretinogram DA 0.01 DA minutes dark adaptation LA Hz Flicker 10 minutes light adaptation

14 Retinitis Pigmentosa 14

15 Residual Cone function - Visual Self Sufficiency Visual self-sufficiency - eg ability to walk out of a well-lighted room without assistance. Loss of visual self-sufficiency (i.e. virtual blindness) - usually occurs when the cone responses fall to about 0.05 µv Eliot L. Berson Long-term visual prognoses in patients with retinitis pigmentosa: The Ludwig von Sallmann lecture Experimental Eye Research 85 (2007)

16 Management of poor vision Optimise vision -Appropriate glasses -Medical therapy -Surgical interventions

17 Driving Standards Clinic issues - Driving will I or won t I be able to drive - What can help if I can t drive Open standard - Visual acuity 6/12 or better in one eye - Visual field 110 degrees horizontal and 10 degrees above and below

18 Driving A conditional license - mechanism for optimising driver and public safety - maintaining driver independence Congenital conditions - People with congenital or childhood conditions may have developed coping strategies that enable safe driving despite their impairment. - individual assessment - Conditions may include - Visual field loss - Nystagmus - Borderline visual acuity up to 6/24

19 Driving and Telescopic aids Amendment 2: Correction relating to use of telescopic lenses for driving 1 st August Telescopic lenses (bioptic telescopes) and electronic aids - These devices are becoming available in Australia. - At present there is little information on the safety or otherwise of drivers using these devices. - In particular, their use may reduce visual perception in the periphery. No standards are set - Recommended that drivers who wish to use these devices be individually assessed by an ophthalmologist/optometrist with expertise in the use of these devices. - UNSW Low vision clinic - Other centres

20 Save Sight Institute Key Partners University of Sydney Faculty of Medicine - Discipline of Ophthalmology Children s Medical Research Institute Sydney Eye Hospital Lions Clubs World Rank Institution Score 1 University College London Harvard University Johns Hopkins University University of Melbourne National University of Singapore University of Sydney University of Southern California University of Miami University of California, Los Angeles University of California, San Diego

21 Thank you SSI Staff - Ellen Brodie - Emma Coleman, - Rebecca Stoop, - Briony Glastonbury, Renee O Kane Matt O Kane Bart Bunting Nathan Hulls Session Speakers - Peter Hickey - Luke Seesink - Jessica Buhne - Susanne Andrews - Kerrie-Ann King - Dr Blake Hamilton Vision Support Agencies - Vision Australia - Guide Dogs - RIDBC - Retina Australia Head Space Association Of Blind Citizen s Of NSW Sydney Eye Lions - Josie Howse