Posters

Association between corneal deformation and ease of lenticule separation from residual stroma in small incision lenticule extraction

Poster Details

First Author: L.Kaveri INDIA

Co Author(s):    R. Shetty   A. Sinha   N. Pahuja   K. Deshpande   M. Thakkar        

Abstract Details

Purpose:

To study association between corneal deformation and intra-operative subjective grading of ease of lenticule separation from residual stroma in small incision lenticule extraction (SMILE).

Setting:

Tertiary eye care centre,Southern India

Methods:

36 eyes of 36 patients underwent SMILE procedure for correction of myopic refractive error. Preoperative manifest refraction, IntraOcular Pressure (IOP) and Central Corneal Thickness (CCT) were evaluated with Scheimpflug imaging. Corneal deformation was measured by air-puff applanation and dynamic imaging. Fourier transform of corneal deformation waveform was also performed. Single surgeon graded the ease of separation of lenticule surfaces from the residual stroma intraoperatively as grades 1 (low effort), 2 (moderate effort) and 3 (high effort). Preoperative corneal deformation outcomes were concealed from the surgeon. Differences between the grades were assessed with one-way analysis of variance.

Results:

Preoperative refraction, IOP and CCT were similar among the grades (p=0.05). Programmed lenticule thickness and incision width were also similar (p >0.05). A total of 5 out of 10 analyzed corneal deformation variables were significantly different among the grades. Among them, deformation amplitude (p=0.001), velocity of corneal apex at 2nd applanation point (p=0.02), peak distance (p=0.006), area under the deformation amplitude (p=0.04) and root mean square of Fourier coefficients decreased from grade 1 to 3.

Conclusions:

Corneal deformation was inversely correlated with the ease of lenticule separation from the residual stroma. Corneal biomechanics may play a role in customizing the energy delivered to separate the lenticule.

Financial Disclosure:

NONE