**2.4 National Eye Institute's Visual Function Questionnaire (NEI VFQ-25)**

NEI VFQ-25 is a questionnaire that checks visual function by focusing on seven visual domains including general vision, near vision, distance vision, peripheral vision, color vision, driving difficulties and ocular pain. DED patients have poor NEI VFQ-25 scores for the subscales of general health, general vision, ocular pain, short distance vision activities, long distance vision activities, vision-related social function, vision-related mental health, vision-related role difficulties, visionrelated dependency, and driving [10, 11].

### **2.5 Dry Eye-Related Quality-of-Life Score (DEQS)**

This questionnaire developed in Japan. It has shown strong correlations with 4 subscales of the NEI VFQ-25 namely Ocular Pain, Near Vision, Distance Vision, and Mental Health [12].

#### **2.6 Computer-vision symptom scale (CVSS17)**

It is a Rasch linear scale containing 17 items. It explores 15 different symptoms of computer-related visual and ocular symptoms and is considered very valuable in computer related ocular morbidities. The CVSS17 includes a broad range of symptoms such as photophobia and excessive blinking [13].

#### **2.7 McMonnies' Questionnaire (MQ )**

It is a screening instruments for DED that reported sensitivity to be varying between 87–98% and specificity between 87% and 97% [14, 15]. It consists of 12 questions. Every question has polytomous response options that vary in number and type [16].

#### **2.8 Ocular Comfort Index (OCI and OCI-C)**

It was developed by Johnson and Murphy in 2007. It allows the quick assessment of the ocular comfort and grading the severity of DED. It uses Rasch analysis to produce estimates on a linear scale. It contains 15 items [17].

#### **2.9 Symptoms Assessment in Dry Eye (SANDE)**

It is based on 100 mm horizontal linear visual analog scale that quantifies both severity and frequency of dry eye symptoms. It consists of 2 questions [18].

#### **2.10 Standard Patient Evaluation of Eye Dryness (SPEED)**

It is based on both frequency and severity of the symptoms of the DED. It was designed to track diurnal and long-term symptom changes over a period of 3 months. The total score was calculated by adding the scores from both the frequency and severity parts of the questionnaire.

The symptoms inquired by the SPEED questionnaire include dryness or grittiness or scratchiness, soreness or irritation, burning sensation or watering and ocular fatigue reported and scored as sometimes – 1, often – 2 and constant – 3 and whether these symptoms pose no problems −0, were tolerable - 1, uncomfortable - 2, bothersome - 3, or intolerable −4 [19].

There are 3 more questionnaires which were developed to diagnose DED in the contact lens wearers –.

#### **2.11 Contact Lens Dry Eye Questionnaire (CLDEQ )**

It was developed by Begley [20]. It was used to investigate the frequency and severity of the symptoms of DED in contact lens wearers. It is quite similar to DEQ but the only difference is that patients here are using contact lens. It consists of 36 items [21]. It divides symptoms into nine subscales -

• Dryness

*Diagnosis of Dry Eye DOI: http://dx.doi.org/10.5772/intechopen.98479*

