A questionnaire that assesses a patient's subjective perception of metamorphopsia correlates well to metamorphopsia measured using two clinical tests.
There are several new clinical tests for metamorphopsia (visual distortion), such as the M-CHARTS test that can quantify the degree of metamorphopsia, and the PreView PHP computer test based on the hyperacuity phenomenon.
By obtaining the patient's subjective impression of metamorphopsia with a questionnaire, eye doctors can compare the severity assessed by clinical tests with the level of subjective metamorphopsia evaluated by the questionnaire
The researchers designed a 10-item questionnaire focusing on the symptoms of metamorphopsia. The questionnaire was given to 39 patients with epiretinal membrane (ERM), 22 patients with macular hole, 19 patients with AMD, and 51 healthy controls. These patients were then tested with both the M-CHARTS and PHP clinical tests.
The questionnaire score significantly correlated to the M-CHARTS score in ERM but not in patients with macular hole, and to the PHP result in AMD but not in ERM. M-CHARTS showed better sensitivities than PHP in both ERM (89% vs. 42%) and AMD (74% vs. 68%) and better specificity (100% vs. 71%) in healthy controls.
These results showed that patients' subjective perceptions of metamorphopsia evaluated by the questionnaire correlated well with the assessments by M-CHARTS and PHP in patients with macular diseases.
The researchers conclude that the metamorphopsia questionnaire can supplement PHP in patients with AMD and can supplement M-CHARTS in patients with ERM and AMD.
WHAT IT MEANS TO YOU: Many patients will remain unaware of significant changes in their vision because they fail to take the time to check how well each eye can see when one eye is covered. It is only by covering one eye that you can truly determine how well each eye is working because when both eyes are open a stronger eye will compensate for a weaker eye. This questionnaire is of value if it encourages patients to think about and check their vision on a regular basis. The normal daily experiences of reading, looking at peoples faces, and seeing telephone poles can be very useful in assessing the quality of your vision without the need for specialized tests, such as the Amsler grid. Any change in your vision should be reported to your eye doctor immediately. But it is extremely important that you close one eye at a time to be certain that changes are not overlooked.Source:http://www.ncbi.nlm.nih.gov/pubmed/20739469