Abstract
Purpose: :
Although cataract extraction is known to be a risk factor for progression of age-related macular changes to choroidal neovascularisation, those who are at especially high risk are difficult to identify. The aim of this study was to follow-up patients who had cataract surgery, to assess progression of age-related changes and to correlate progression with ARM risk profile.
Methods: :
Eighty patients had digital retinal imaging day 1 postoperatively and had venous blood taken for DNA extraction. Retinal images were graded at baseline according to the Rotterdam ARM severity scale. Forty-one patients had either stage 0a or 0b retinal changes and were invited for review and repeat imaging 24 months later. Genetic haplotyping was carried out on these patients for CFH, CFB, ARMS2 and CC3. Smoking risk was also assessed. Genetic risk for each individual was calculated using logistic regression analysis as detailed by Hughes et al.1 Retinal images were graded in a coded manner for ARM by a retinal specialist (GS). A change in grade was deemed significant if it changed by 1 or more complete grade e.g. 1a -to 2a. Clinical progression of ARM finding was correlated with risk profile.
Results: :
Forty-one patients were invited for review of which 28 attended, 9 were deceased and 4 declined. Images were available for grading on 25 target eyes. Genetic and smoking data was available for 37 individuals. Five eyes had progressed and 22 remained stable. Risk profiles were constructed for each patient and were classified as High risk: Odds Ratio (OR)>50; Moderate risk: 20<OR<50; Low risk: OR< 20 . Of the total sample 21.6% were in the High risk group, 32.4% were in the Moderate risk group, 45.9% were in the Low risk group. Of the 5 patients who progressed, complete data were available on 4, 3 (37.5%) of which had High risk and 1 (8.3%) had Moderate risk. None of the patients in the Low risk category progressed. Deceased patients were not specific to any risk category.
Conclusions: :
Although sample size in this pilot study is small 18.5% of patients showed progression. Those patients who progressed had either a high or moderate genetic risk profile. We plan to undertake the same risk assessment on patients undergoing cataract surgery with moderate pre-existing ARM levels (stage 2a - 3) as they are more likely to progress over a 2 year period and enable additional correlation with risk profile.
Keywords: age-related macular degeneration • cataract • gene screening