Laserkanthoplasty – Assessment of laser parameters to improve lid tension

Abstract

Purpose : Preliminary clinical work in patients with eyelid laxity indicates that increasing eyelid tension with a surgical procedure does improve the function of the Meibomian glands and symptoms of dry eye disease. The aim of this study was to develop a minimally invasive laser irradiation to increase eyelid tension of the lateral tarsal plate and canthus.

Methods : Ex vivo experiments were performed on a total of 24 porcine lower eyelids post mortem (table 1). Groups were irradiated with different laser settings (wavelength/power/duration) using an infrared B radiation laser. Three laser coagulation spots were applied to the conjunctival side of each eyelid. Laser-induced lower eyelid shortening was measured and the increase in eyelid tension was quantified with a force sensor. Histology was performed to assess the coagulation size. A grading system (grade 0-3) was developed to determine epithelial detachment and tissue destruction (illustration 1). Picro-Sirius Red Stain (PS) was used to distinguish the irradiated area in different birefringent zones and to calculate the volume of the zones.

Results : After irradiation, the strongest longitudinal shortening resulted in group 3 (-15.1±3.7%=-2.5±0.6 mm; p<0.0001). The largest significant increase in eyelid tension was seen after the 3rd coagulation in all groups (1: p=0.01; 2: p=0.04; 3: p=0.004). Group 3 showed significantly the deepest (1071.8±70.8 µm) and largest coagulation (2910.8±220.6 µm). The grading of laser damage showed least destruction in group 3 (grade 0.8±1.2, group I vs. III p=0.03) with minor to minimal epithelial detachment and no tissue destruction. Two different zones were distinguished: a coagulation and a transition zone. The approximated coagulated tissue volume of group 1470 nm was significantly larger than that of the other coagulation zones (4.86±0.99 mm³, p<0.0001).

Conclusions : Laser coagulation of the posterior lamella leads to eyelid shortening and increase of lower eyelid tension. The laser parameters of group III showed the strongest and least destructive effect. A longer-term effect of laser tarso-canthoplasty must be tested in vivo.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Table 1: Laser parameter combinations of the treatment groups.

 

Illustration 1: Grading system to evaluate severity of morphologic changes of the porcine conjunctiva of the eyelid after laser irradiation. Scale bar: 500 µm.