Glaucoma is often described as 'the silent thief of sight'.
This presupposes that patients are not aware of any visual problems
until the end stage.
The conventional view is WRONG
There is ample evidence1,2,3 that patients are aware
of problems despite relatively minor binocular field loss.
A patient who notices gradual visual deterioration is twice as likely
to have bilateral field progression as not.3
In order to forge a closer link between standard clinical tests
and patient perception, we need to estimate the binocular visual field.
This begs the question:
Is it possible to merge bilateral monocular field tests to
predict the binocular field?
Yes.
Several studies4,5,6 have shown that the Integrated Visual
Field (predictions based on the highest sensitivity between eyes at
each visual field test location) predicts the binocular field accurately.
The Integrated Visual Field is more closely linked to patient perception
than formal Esterman testing.6,7
The Integrated Visual Field test agrees well with the current method
(Esterman) of classifying visual fields with regard to legal fitness
to drive in the United Kingdom in patients with
glaucoma; it appears superior to the current method in identifying those
with reduced fitness to drive.8
References
Nelson P, Aspinall P, Papasouliotis O, Worton B, O'Brien C. Quality
of life in glaucoma and its relationship with visual function. J
Glaucoma 2003; 12: 139-150.
Noe G, Ferraro J, Lamoureux E, Rait J, Keeffe JE. Associations between
glaucomatous visual field loss and participation in activities of daily
living. Clin Experiment Ophthalmol 2003; 31: 482-486.
Viswanathan AC, McNaught AI, Poinoosawmy D, Fontana L, Crabb DP,
Fitzke FW, et al. Severity and stability of glaucoma: patient
perception compared with objective measurement. Arch Ophthalmol
1999; 117: 450-454.
Crabb DP, Viswanathan AC, McNaught AI, Poinoosawmy D, Fitzke FW,
Hitchings RA. Simulating binocular field status in glaucoma. Br J
Ophthalmol 1998; 82: 1236-1241.
Nelson-Quigg JM, Cello K, Johnson CA. Predicting binocular visual
field sensitivity from monocular visual field results. Invest Ophthalmol
Vis Sci 2000; 41: 2212-2221.
Jampel HD, Friedman DS, Quigley H, Miller R. Correlation of the
binocular visual field with patient assessment of vision. Invest
Ophthalmol Vis Sci 2002; 43: 1059-1067.
Crabb DP, Viswanathan AC. Integrated visual fields: a new approach
to measuring the binocular field of view and visual disability. Graefes
Arch Clin Exp Ophthalmol 2004.
Crabb DP, Fitzke FW, Hitchings RA, Viswanathan AC. A practical approach
to measuring the visual field component of fitness to drive. Br J
Ophthalmol 2004; 88: 1191-1196.