Endothelial Bleb Response With Toric Lenses

Evaluation of the Short-Term Corneal Endothelial Response to Wear of Toric Soft Contact Lenses in Asian Eyes

Evaluate the short-term corneal response of oxygen deprivation when using toric contact lenses. The response will be noted by endothelial bleb formation in both open eye and closed eye state.

Interested subjects who meet the entry criteria for the study will be scheduled for four sessions of approximately 30 minutes duration each. Informed consent obtained. Baseline measurements of visual acuity and corneal and conjunctival physiology will be recorded. An examination of the endothelium of the corneas will be conducted using the specular microscope, readings obtained at 5 locations on each cornea: one in the centre and one in each of the superior, inferior, nasal and temporal peripheral regions, approximately 2mm from the limbal margin. The assigned lenses will be inserted according to a fixed-allocation randomization schedule, where each session follows an optimized 2- period simultaneous crossover design, which specifies lenses to be used in each of the four sessions. Lenses will be worn for 20 minutes and then removed. Endothelial specular microscopy will be conducted at 20 minutes with the lenses on. A final evaluation of corneal and conjunctival physiology will be performed prior to subject clearance from the study.

Subjects were first randomized to a session and then randomized to receive one of four lens sequences for that session. Each subject participated in all four sessions. Session A only contains senofilcon A toric and alphafilcon A toric lenses.

Subjects were first randomized to a session and then randomized to receive one of four lens sequences for that session. Each subject participated in all four sessions. Session B only contains senofilcon A toric and alphafilcon A toric lenses.

Subjects were first randomized to a session and then randomized to receive one of four lens sequences for that session. Each subject participated in all four sessions. Session C only contains senofilcon A toric and lotrafilcon B toric lenses.

Subjects were first randomized to a session and then randomized to receive one of four lens sequences for that session. Each subject participated in all four sessions. Session D only contains senofilcon A toric and lotrafilcon B toric lenses.

Subjects that were randomized to receive alphafilcon A toric during one of the four sessions (Sessions A, B, C and D).

Subjects that were randomized to receive lotrafilcon B toric during one of the four sessions (Sessions A, B, C and D).

Subjects that were randomized to receive senofilcon A toric during one of the four sessions (Sessions A, B, C and D).

Mean area of endothelial blebs in the following corneal locations: Central, Nasal, Temporal, Inferior, Superior. A masked observer performed the analysis by subjectively selecting a region in a given image that provided an optimal balance of maximum area and clarity of cell outlines. Blebs were then outlined manually and the software calculated the area of blebs. The different sessions are reported showing results for each lens according to the lens worn in the contralateral (contra) eye.Open eye sessions simulated the subjects normal ocular behavior during waking hours; closed eye sessions simulated ocular activity during duration of closed eye activity, such as sleeping. Results are reported as the mean percent difference between the stated test (senofilcon A) and the control lens (alphafilcon A, lotrafilcon B), after 20 minutes of wear, for each testing scenario.

Mean area of endothelial blebs in the following corneal locations: Central, Nasal, Temporal, Inferior, Superior. A masked observer performed the analysis by subjectively selecting a region in a given image that provided an optimal balance of maximum area and clarity of cell outlines. Blebs were then outlined manually and the software calculated the area of blebs. The different sessions are reported showing results for each lens according to the lens worn in the contralateral (contra) eye.Open eye sessions simulated the subjects normal ocular behavior during waking hours; closed eye sessions simulated ocular activity during duration of closed eye activity, such as sleeping. Results are reported as the mean percent difference between the stated test (senofilcon A) and the control lens (alphafilcon A, lotrafilcon B), after 20 minutes of wear, for each testing scenario.

Mean area of endothelial blebs in the following corneal locations: Central, Nasal, Temporal, Inferior, Superior. A masked observer performed the analysis by subjectively selecting a region in a given image that provided an optimal balance of maximum area and clarity of cell outlines. Blebs were then outlined manually and the software calculated the area of blebs. The different sessions are reported showing results for each lens according to the lens worn in the contralateral (contra) eye.Open eye sessions simulated the subjects normal ocular behavior during waking hours; closed eye sessions simulated ocular activity during duration of closed eye activity, such as sleeping. Results are reported as the mean percent difference between the stated test (senofilcon A) and the control lens (alphafilcon A, lotrafilcon B), after 20 minutes of wear, for each testing scenario.

Mean area of endothelial blebs in the following corneal locations: Central, Nasal, Temporal, Inferior, Superior. A masked observer performed the analysis by subjectively selecting a region in a given image that provided an optimal balance of maximum area and clarity of cell outlines. Blebs were then outlined manually and the software calculated the area of blebs. The different sessions are reported showing results for each lens according to the lens worn in the contralateral (contra) eye.Open eye sessions simulated the subjects normal ocular behavior during waking hours; closed eye sessions simulated ocular activity during duration of closed eye activity, such as sleeping. Results are reported as the mean percent difference between the stated test (senofilcon A) and the control lens (alphafilcon A, lotrafilcon B), after 20 minutes of wear, for each testing scenario.

Inclusion Criteria: Successful soft contact lens wear in daily mode for a minimum of 1 month prior to start of the study without experiencing difficulties or contact lens related complications. At least 18 years of age and mentally competent to sign an informed consent form. Healthy eyes and no use of ocular medication. Similarity of optical parameters between eyes. Physical appearance typical of Asian eyes Exclusion Criteria: A medical or ocular condition that may influence the outcome of this trial. Current use of ocular/systemic medication that may influence the outcome of this trial. Failure to wear soft lenses for 2 weeks prior to the start of the study. Current enrolment or participation in another clinical study. Current state of pregnancy or breastfeeding Anisometropia greater than 1.00D (equivalent sphere). Unequal acuities between eyes (greater than 1 line) Unequal corneal curvatures (>1.00D)