Abstract
Purpose: :
Evaluate the differences in visual quality (VQ) metrics between the subjects with Sjögren’s dry eye (SSDE) and non- Sjögren’s aqueous deficient dry eye (ADDE) using a wavefront sensor.
Methods: :
: Two groups of dry eye subjects were recruited: 8 SSDE and 9 ADDE (total 17 eyes). The mean Schirmer’s-I test score(5.4 ± 1.8 mm and 4.9 ± 2.6 mm ) and tear break-up time (3.2 ± 0.5 seconds and 3.8 ± 0.8 seconds) between the SSDE and ADDE groups were not significantly different. Real time changes in ocular aberrations were measured using a custom built Shack-Hartmann wavefront sensor. Measurements were taken during a period of forced eye opening for about 10 seconds each and were repeated for 3 blink cycles. The measured ocular aberrations were then analyzed to compute the area under modulation transfer function (aMTF). Three different VQ metrics were defined from the aMTF. These include the overall VQ (average aMTF), stability of VQ (standard deviation of aMTF) and time course of VQ (slope of aMTF).
Results: :
On average the overall VQ in the ADDE group was better than in the SSDE group, though a statistical significance was not found. The stability of VQ was significantly better in the ADDE group than in the SSDE group (P=0.04).The time course of VQ showed a worsening trend of VQ over time in both groups. The SSDE group had a greater worsening with a 38% decrease in VQ over a 10 second blink interval (R2 = 0.77) than in the ADDE group with a 14% decrease (R2 = 0.64). This difference was statistically significant (P = 0.01).
Conclusions: :
Real time ocular wavefront measurements provide objective assessment of tear dynamics in dry eye patients. Time course changes in VQ and stability of VQ are capable of differentiating the Sjögren’s type of dry eye from a simple ADDE.
Keywords: cornea: tears/tear film/dry eye • autoimmune disease