Presence of reticular degeneration of the pigment epithelium is associated with both choroidal neovascularisation and geographic atrophy forms of end-stage age-related macular degeneration.

Joshua Yuen1, Humma Shahid2, John RW Yates3, Anthony T Moore4 and Jane C Khan1
for the Age-related macular degeneration Study Group

Purpose
To investigate the incidence of peripheral retinal reticular degeneration of the pigment epithelium (RDPE) in association with end-stage AMD.

Methods
A case-control study compared cases with end-stage AMD with spouse controls. Fundus photographs were graded according to the International Classification of Age-related Maculopathy and Macular Degeneration1. Data on sun exposure, age of onset, bilaterality of AMD and smoking were obtained from a detailed questionnaire. Iris colour was assessed independently by the interviewer and by the clinician based on the grading scheme of Seddon et al2. Presence and severity of RDPE was assessed.

Results
Four hundred and thirty-five cases with end-stage AMD were compared with 280 spouse controls. There was a strong association between end stage AMD and presence RDPE and the relationship was similar for both end stage forms of disease (P<0.001, OR=4.1 95% CI 2.8-6.1). Presence of RDPE was associated with slightly increased odds of lighter iris colour (OR 1.7, 95% CI 1.0- 3.1) but this was not statistically significant. Similarly there were increased odds with higher pack years of cigarette smoking (OR 1.4, 95%CI 0.7-3.0) but not reaching statistical significance. There was no association between sun exposure and presence of RDPE. There was no association between presence of RDPE and bilateral AMD over unilateral nor any association with earlier age of onset of AMD.

Conclusions
This study has demonstrated a strong association of RDPE and presence of end-stage AMD. The presence of RDPE does not appear to be influenced by smoking, sun exposure or iris colour.

Acknowledgements
The following investigators also contributed to this work as part of the Genetic Factors in AMD Study:

SS Bhattacharya, P Bishop, P Black, Z Butt, NE Day, C Edelsten, A Fitt, DW Flanagan, A Glenn, S Harding, C Jakeman, C Jones, RJ Lamb, A Lotery, V Moffat, C Moorman, A Nicholas, Push, E Redmond, T Rimmer. With special thanks to Tunde Peto for directing the fundus photgraph grading and Kay-Tee Khaw for advice on the patient questionnaire. We also appreciate the help of the clinic staff and medical photographers at the Addenbrookes Centre for Clinical Investigation, Cambridge; Ipswich Hospital; Peterborough Hospital; Moorfields Eye hospital, London; Norfolk and Norwich University Hospital, Norwich; West Suffolk Hospital, Bury St Edmunds; Queen Elizabeth Hospital, Kings Lynn; James Paget Hospital, Great Yarmouth; Stoke Mandeville Hospital, Aylesbury, Southampton General Hospital. We appreciate the work done in processing the DNA samples by Whatman laboratories. Many thanks to all the patients and their families who participated in this study.

This work was supported by a programme grant from the Medical Research Council, UK

Reference List

1. Bird AC, Bressler NM, Bressler SB, Chisholm IH, Coscas G, Davis MD et al. An international classification and grading system for age-related maculopathy and age-related macular degeneration. The International ARM Epidemiological Study Group. Surv.Ophthalmol. 1995;39:367-74.
2. Seddon JM, Sahagian CR, Glynn RJ, Sperduto RD, Gragoudas ES. Evaluation of an iris color classification system. The Eye Disorders Case-Control Study Group. Invest Ophthalmol Vis.Sci. 1990;31:1592-8.