To assess the meibomian glands, the secretion characteristics from 15 gland orifices along the lower eyelid were evaluated under a slit lamp biomicrosope using a handheld instrument, Meibomian Gland Evaluator, to apply gentle standardized pressure to the eyelid margin. Expressed secretion characteristics were graded on a scale of 3 (clear liquid secretion), 2 (cloudy liquid secretion), 1 (inspissated/toothpaste consistency), and 0 (no secretion). Total meibomian gland score was calculated based on the sum of the secretion grades for all 15 glands over a range from 0 to 45 with a higher score reflecting less meibomian gland dysfunction. To be eligible for the study, the Baseline total meibomian gland score must have been 12 or less in each eye. Change = 3 Month score - Baseline Score.

Intent to Treat Population (All Participants who were randomized and received at least partial LipiFlow treatment or used warm compress therapy at least once and had data available at 3 Months).

To assess the meibomian glands, the secretion characteristics from 15 gland orifices along the lower eyelid were evaluated under a slit lamp biomicrosope using a handheld instrument, Meibomian Gland Evaluator, to apply gentle standardized pressure to the eyelid margin. Expressed secretion characteristics were graded on a scale of 3 (clear liquid secretion), 2 (cloudy liquid secretion), 1 (inspissated/toothpaste consistency), and 0 (no secretion). Total meibomian gland score was calculated based on the sum of the secretion grades for all 15 glands over a range from 0 to 45 with a higher score reflecting less meibomian gland dysfunction. The total meibomian gland score at 12 Months was compared across subgroups, as defined below.

Intent to Treat Population (All participants who received at least partial LipiFlow or Crossover LipiFlow treatment and had data available at 12 Months). Two LipiFlow treatments subgroup was not analyzed because sample size was too small (n<5) for meaningful analysis.

Dry eye symptoms assessed using the OSDI questionnaire were sensitivity to light, grittiness, pain or soreness, blurred vision and poor vision. The questionnaire evaluated the frequency problems with the eyes limited performance in reading, driving at night, working with a computer or bank machine, and watching television. Also, the frequency that eyes felt uncomfortable was assessed in windy conditions, areas with low humidity, and air-conditioned areas. The frequency scale was 0 (none of the time), 1 (some of the time), 2 (half of the time), 3 (most of the time), and 4 (all of the time). The total OSDI score was calculated as the sum of frequency scores for all symptoms multiplied by 25 and divided by the number of questions answered with a range from 0 to 100. A lower total OSDI score represents less disability from dry eye symptoms. To be eligible for the study, the Baseline total OSDI score must have been 13 points or higher in each eye. Change=3 Months score-Baseline score.

Intent to Treat Population (All participants who were randomized and received at least partial device treatment or used warm compress at least once and had data available at 3 Months).

Dry eye symptoms assessed using the OSDI questionnaire were sensitivity to light, grittiness, pain or soreness, blurred vision and poor vision. The questionnaire evaluated the frequency problems with the eyes limited performance in reading, driving at night, working with a computer or bank machine, and watching television. Also, the frequency that eyes felt uncomfortable was assessed in windy conditions, areas with low humidity, and air-conditioned areas. Frequency scale was 0 (none of the time), 1 (some of the time), 2 (half of the time), 3 (most of the time), and 4 (all of the time). The total OSDI score was calculated as the sum of frequency scores for all symptoms multiplied by 25 and divided by the number of questions answered with a range from 0 to 100. A lower total OSDI score represents less disability from dry eye symptoms. The total OSDI score at 12 Months was compared across subgroups, as defined below.

Intent to Treat (All participants who received at least a partial LipiFlow treatment or Crossover LipiFlow treatment and had data available at 12 Months). The Two LipiFlow treatments subgroup was not analyzed because the sample size (n<5) was too small for meaningful analysis.