Evaluating The Surgical Induced Corneal Astigmatism For The Scleral Fixated Carlevale Lens

To evaluate the surgical induced astigmatism (SIA) in patients who have undergone scleral intraocular lens (IOL) fixation. 

Department for Ophthalmology and Optometry, Medical University of Vienna, Austria

This prospective single surgeon follow up study involved patients who underwent transscleral IOL implantation using the Carlevale technique due to spontaneous IOL dislocation or complicated cataract surgery.

The preoperative and postoperative corneal astigmatisms were measured using the Casia 2 anterior segment optical coherence tomograph (AS-OCT). Subsequently the SIA and its course were calculated for the timepoints of 2weeks, 3 months and 6 months postoperatively, using the Casia 2 inbuilt software. 

Additionally corneal thickness at the apex and the thinnest spot were evaluated at all corresponding timepoints. 

A total of 23 eyes of 23 patients could be included. Mean corneal astigmatism prior to surgery was 1.14 ± 0.82 D.

Mean postoperative corneal astigmatism at month 6 was 1.07 ± 0.65, there was no significant difference between baseline and month 6 (p=0.9992).

SIA 2 weeks postoperatively was 2.08±1.6 D, decreasing significantly to 0.79±0.61 at month 3 (p=0.0016) and then stabilizing around 0.83±0.79 at month 6 (p=0.9924) postoperatively, respectively. 

Mean corneal thickness at the apex was stable during follow up 569±66µm (baseline), 573±65µm (week 1), 555±45µm (month 3) and 559±50µm (month 6), respectively (all ps>0.4).

The SIA peaked at 1 week after surgery at around 100°, which might be a result of mainly CCI wound hydration and thread tension at the site of the scleral pockets. 

SIA decreased significantly at month 3 in most of the patients, leading to similar corneal astigmatism as prior to surgery.

Thus, the Carlevale method proved to be a very astigmatism neutral procedure, however patience is needed for some patients until corneal astigmatism returns to baseline values.