Abstract
Purpose: :
To compare Scanning Laser Ophthalmoscope (SLO) central field and PRL characteristics in current low vision patients to a study reported in 1997.
Methods: :
501 eyes of 273 recent patients referred for low vision rehabilitation had visual acuity (ETDRS), macular perimetry for dense scotomas (SLO) and PRL characteristic (SLO) testing performed in their initial evaluation. The size of scotomas, PRL position relative to scotomas, and relative to the fovea were noted. A scotoma within 2.5 degrees of the PRL or fovea to either superior, right, left or inferior margins was considered a bordering scotoma. This constituted a repeat study of 1336 eyes of 825 patients reported in Ophthalmology 1997 to which comparisons are made.
Results: :
Demographic and diagnostic characteristics were similar, with median ages close to 80 and more than two thirds having maculopathies in both studies. 34% (1997) and 30% (2007) of patients had < 20/400 visual acuity. 91% (1997) and 88% (2007) of patients had dense scotomas in the central 20 degrees. 69% (1997) and 66% (2007) had dense scotomas larger than 5 degrees diameter. PRLs/Foveas with dense scotoma borders: None - 11% (1997) and 18% (2007); One Border - 41% (1997) and 37% (2007); Two Borders - 19% (1997) and 22% (2007); Three Borders - 9% (1997) and 8% (2007); Four Borders/Ring Scotoma - 19% (1997) and 15% (2007). PRLs/Foveas with dense scotoma field borders: Superior - 46% (1997) and 48% (2007); Right - 49% (1997) and 49% (2007); Left - 32% (1997) and 40% (2007); Inferior - 29% (1997) and 28% (2007). With respect to foveal status, in 1997 only 18% of patients had a functioning fovea where as in 2007 50% had a functioning fovea.
Conclusions: :
In 2007 the vast majority of low vision patients present with central visual field disruption, as was the case in 1997. Characteristics in the position of the scotoma relative to the PRL/Fovea remained remarkably consistent. There is a small tendency to fewer patients with profoundly impaired visual acuity and fewer with large scotomas. Currently more patients present for low vision rehab with functioning foveas than 10 years ago. More functioning foveas has implications for rehabilitation services and may also reflect positively on new treatments for exudative maculopathies not available 10 years ago.
Keywords: low vision • visual fields • visual acuity