Characteristics of central scotoma in glaucoma

Objective To study the clinical features of central scotoma in glaucoma.Methods A retrospective non-controlled study.Central scotomas were screened from glaucomatous visual field data.Then the shape,the distribution and the progression of central scotoma were analyzed.In addition,visual acuity and fundus of involved eyes were studied.Moreover,we calculated the ratio of central scotomas in early glaucomatous visual field defects.Incidence difference of this kind of scotoma was compared among primary open angle glaucoma(POAG),normal pressure glaucoma(NPG)and primary angle-closure glaucoma(PACG).Results Central scotomas occurred in glaucomatous eyes were semi-central ones limited by the horizontal meridian and seldom crossed this line even in progression.It could be found more in superior field than in the inferior and hadn′t affected visual acuity.Local retinal nerve fiber layer defect were detected in involved eyes and were close to papillo-macular bundles.We found 10 5% of the early glaucomatous visual field damage to be central scotoma and NPG was 15 9%,POAG was 7 5% while PACG was 5 2%.The incidence was statistically higher in NPG than in POAG or PACG( P 0 05).There was no difference between POAG and PACG( P 0 05).Conclusions Central scotoma occurred in glaucoma is different from which in other diseases and we can make differentiations from the clinical features concluded above.There was a higher incidence in NPG than in other glaucomas and further study should be taken to reveal the mechanism.