Clinical Application Comparison of Two Femtosecond Laser Systems

The ocular staining score ranged from 0 to 12. A score of 0 indicated no corneal or conjunctival staining with fluorescein or lissamine green dye, respectively. A score of 12 indicated severe staining of the cornea and conjunctiva with confluent and central fluorescein staining, the presence of corneal filaments, and confluent areas of lissamine green of the bulbar conjunctiva of greater than or equal to 4 mm2.

The ocular staining score ranged from 0 to 12. A score of 0 indicated no corneal or conjunctival staining with fluorescein or lissamine green dye, respectively. A score of 12 indicated severe staining of the cornea and conjunctiva with confluent and central fluorescein staining, the presence of corneal filaments, and confluent areas of lissamine green of the bulbar conjunctiva of greater than or equal to 4 mm2.

The dry-eye questionnaire-5 (DEQ-5) is a validated questionnaire that has been shown to discriminate between different severities of dry eye. Participants self-assessed the frequency and severity of eye discomfort, eye dryness, and watery eyes experienced during the evening of a typical day within the last month. Responses were given using a Likert scale with scoring criteria from 0 = never experienced the symptom to 5 = extremely severe experience of symptom. The sum of the scores from the five questions was used in the analysis.

Ocular surface disease index (OSDI) is a widely accepted questionnaire on subjective symptoms in patients with dry eyes. It consisted of 12 questions on eye-related symptoms, vision-related function, and environment-related symptoms. Each question is evaluated according to the frequency of occurrence: never, 0 point; occasionally, 1 point; often, 2 points; most of the time, 3 points; all the time, 4 points. Not all the 12 questions needed to be answered. If the question is that the patient didn't participate in the activity or the environment that would not be in the case, it would not be answered and scored. The final score is calculated according to the formula: OSDI values=(sum of all survey items)×100/(answered survey items)×4.

The tear meniscus assessment height was measured with the Ocular Surface Analyser (SBM Sistemi, Orbassano, Italy)

Noninvasive tear film breakup time was assessed automatically using the Ocular Surface Analyser (SBM Sistemi, Orbassano, Italy). The participants were instructed to blink naturally two times and then to cease blinking until instructed to blink again. Three measurements were performed for each eye and the average for each eye included for analysis.

The tear-film assessment was assessed with the Ocular Surface Analyser (SBM Sistemi, Orbassano, Italy).

The Schirmer I test was carried out under natural light. A 5 mm×35 mm Schirmer test strip was placed in the middle and outer 1/3 junction of the lower conjunctival sac of the affected eye without anesthesia. The patient was asked to close eyes gently. After 5min, the strip was removed and the wet length of the strip was measured. Values less than 5 mm are indicators for dry eye syndrome.