A Systematic Review: What is the Normative Size of the Blind Spot Scotoma in Adults?

Background: Blind spot enlargement can be caused by a range of medical conditions and monitoring the size of the blind spot scotoma can indicate progression of disease.

Objectives: The aim of this review is to establish the size of the blind spot scotoma in adults free of ocular pathology in order to aid identification of any scotoma enlargement.

Search Methods: The following electronic databases were searched; Ovid Medline, Ovid SP, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Google Scholar and the Cochrane Central Library.

Searches were then conducted of the following individual journals; British Medical Journal, British Journal of Ophthalmology, Journal of Neurology, European Journal of Neurology, Archives of Ophthalmology, American Academy of Ophthalmology, Ophthalmology, Brain, and Eye.

Selection Criteria: No study designs were to be excluded. Few relevant articles were found and so no publication timeframes were imposed.

Results: The identified literature is reviewed and discussed in relation to the equipment used to measure the size of the blind spot scotoma. The equipment used to measure the blind spot scotoma included; Tangent Screen, Goldmann, Tubingen Computer Campimeter, Stereo-campimeter and Ferree-Rand. This review found the size of the blind spot scotoma to be dependent on the method used to measure it.

Conclusion: Clinicians need to have accurate information on the instruments they use to successfully monitor changes in the size of the blind spot scotoma. Further research needs to be conducted using clinically relevant equipment, such as the Octopus 900 which allows clinicians to move the kinetic stimulus at a constant speed and account for the patient’s reaction time.