VISUAL FIELD PITFALLS : ABOUT 40 CASES.

The visual field is a functional test which has an essential contribution to the ophthalmological examination. Its analysis remains essential in the monitoring of glaucoma patients, to evaluate the effectiveness of a therapy and judge the evolution of the pathology. However, multiple factors often limit its use and despite automation and sophisticated statistical analyses, perimetry has several pitfalls.

On the basis of a rich iconography and data from the literature, our work consisted of studying all the factors which can distort the results of this examination - whether the realization pitfalls, the retinal and pre-retinal pitfalls or the pitfalls related to neurological causes which allows the practitioner and the orthoptist to avoid them during its production and interpretation.

The present work is a retrospective analytical study covering 40 files and therefore 80 visual fields among 432 files of patients followed for "glaucoma" at the Moulay Ismail military hospital in Meknes, spread over a period of 7 years.

Patients with visual field pitfalls had a prevalence of 9.25%. At the end of this revision the distribution of patients according to the final diagnosis is as follows: 29 cases of accommodative spasms, 8 cases of realization pitfalls, 7 cases of cataract, 6 cases of dryness, 4 cases of each of the following diagnoses: retinopathy hypertensive, laser diabetic retinopathy, anisometropia with amblyopia, central serous chorioretinitis, 2 cases of each of these pathologies: high myopia, non-proliferative diabetic retinopathy, keratitis, papillary dysversion and pterygium, and finally only 1 case of congenital peripapillary atrophy, branch retinal vein occlusion, ischemic optic neuropathy and epimacular membrane.

Suggestions for preventing these visual field pitfalls:

• Successful communication between the perimetrist and the patient is of utmost importance.
• The patient must be comfortably and correctly positioned.
• Always consider the complete clinical picture, including the role of coexisting conditions.
• The OCT and visual field correlation has an essential contribution.