Background: Surgical removal of subretinal hemorrhaging and membranes in eyes with age-related macular degeneration is feasible from a technical point of view, but no advantage over the spontaneous course of the disease has been proven. Visual acuity usually does not improve much. A realistic aim of surgical intervention may be diminution of the central scotoma size, which has not been studied.
Method: In a prospective study visual fields were measured preoperatively and 6 weeks and 6 months postoperatively in eyes operated on for subretinal hemorrhages and membranes in exudative age-related macular degeneration. The OCTOPUS 1-2-3 program glx, which tests the visual field of 60 degrees diameter at 59 points, was used. Changes in the total size of areas with sensitivity loss of 10-20 dB (= relative scotoma) and > 20 dB (= absolute scotoma) were interpreted as surgical effect. Patients with postoperative retinal detachment or neovascular recurrence were excluded. 30 eyes of 29 patients were enrolled (mean age 75.3 years, 11 male, 18 female) and divided into 3 groups: 14 eyes with massive subretinal hemorrhage of diameters > 30 degrees; 12 eyes with hemorrhages of 10 degrees-30 degrees; 4 eyes with mere neovascular membranes < 10 degrees.
Results: (1) The visible area of damage is diminished by surgery (P < 0.01). The reduction for lesions > 30 degrees is 80%; for lesions between 10 degrees and 30 degrees the improvement is 43%. For lesions < 10 degrees there is no significant change. (2) The absolute scotoma size diminishes in all three groups (P = 0.05). The reductions are 63%, 57% and 21%, respectively. (3) Areas of absolute scotoma do not regain full function but are converted to relative scotoma depth, at best. Therefore, in the > 30 degrees group an overall increase (P < 0.01) of the relative scotoma size is observed. (4) The mean sensitivity in the 60 degrees field enhances by 1.6 dB (average over 30 eyes, P = 0.04). (5) Mean preoperative visual acuities were 0.03, 0.12 and 0.17, respectively, with no significant change after surgery. The power of testing is sufficient (0.93) to reject an increase of acuity from 0.12 to 0.2 in group 2.
Conclusions: For hemorrhagic subretinal lesions of diameter > 10 degrees a relevant reduction of central scotoma size is achieved by surgery. The final benefit for the patients depends on the frequency of surgical complications and neovascular recurrence.