Therapeutic Contact Lens-Assisted Optical Coherence Tomography For Detection Of Posterior Segment Pathology In Patients With Corneal Edema

Posterior segment optical coherence tomography (OCT) represents an important tool to detect retinal and optic nerve comorbidities during the preoperative evaluation of patients undergoing corneal transplantation. However, corneal edema can reduce the quality of OCT images possibly leading to missed or erroneous diagnosis. The purpose of this study was to evaluate the effect of the application of a therapeutic contact lens on the detection rate of posterior segment diseases by OCT of the macula and optic nerve head in eyes with corneal edema.

Ospedali Privati Forlì “Villa. Igea”, Forlì, Italy.

 

This prospective study included 20 patients with corneal edema undergoing endothelial keratoplasty in our Institution from September to December 2021. Macular and optic nerve head OCT acquisitions were obtained using the Spectralis HRA-OCT (Heidelberg Engineering, Heidelberg, Germany) first without a contact lens, and then repeated with placement of a therapeutic contact lens. The OCT quality was measured by using the signal strength provided by the device and subjectively graded on a 4-point scale based on visibility of retinal details (grade 1: no visible structure; grade 2 barely visible retinal profile; grade 3: retinal profile identified with ease; grade 4: visibility of all individual retinal layers).

The signal strength of macular and optic nerve head OCT significantly improved with contact lens application (from 14.6±7.8 to 20.0±6.0, P<0.001 and from 9.8±6.0 to 12.6±6.9, P<0.001, respectively). The subjective quality grading also improved with contact lens in both macular and optic nerve head OCT (from 2.9±1.0 to 3.6±0.5, P=0.002 and from 2.8±1.2 to 3.3±1.2, P=0.031, respectively). In 2 patients, cystoid macular edema could be detected only with contact lens application. In 1 case with apparent retinal nerve fiber layer (RNFL) thinning without contact lens, the measurement of RNFL with contact lens was normal. In 2 cases with apparently normal RNFL measurement without contact lens, RNFL thinning was detected with contact lens.

Macular and optic nerve head OCT quality significantly improved with application of a therapeutic contact lens in patients with corneal edema. This represents a simple and readily available solution to increased detection rate of retinal and optic nerve comorbidities. Preoperative detection of posterior segment pathologies in eyes requiring endothelial keratoplasty can allow to determine the best management strategy, provide appropriate patient counselling and set expectations regarding postoperative visual outcomes.