Tackling High Astigmatism With A Toric Iol In A Case Of Terrien Marginal Degeneration - A Long Term Follow-Up Analysis

Terrien marginal degeneration (TMD) is a slowly progressive cause of peripheral corneal thinning. Corneal changes yield high astigmatism, which impairs vision and is difficult to manage. In this report we describe the use of a toric intraocular lens (IOL) following cataract surgery for correction of high astigmatism in TMD with favourable postoperative outcome.

Department of Ophthalmology, Unidade Local de Saúde de Vila Nova de Gaia/Espinho.

Observational case report of a 56-year-old woman who was referred to our department for high astigmatism and progressive intolerance to spectacle/contact lens (CL) vision correction. Her last 3 spectacle prescriptions (over the course of 5 years) showed a small increase in cylindrical power within the same axis.

Upon evaluation best corrected visual acuity (BCVA) was 10/10 (+4.00-8.00x100º) in right eye (RE) and 6/10 (+3.25-10.00x80º) in left eye (LE). Biomicroscopy showed superior thinning with an intact epithelium, lipid deposition and superficial vascularization. A diagnosis of TMD was made.
Two years later there was a 1D increase of astigmatism in LE, without axis change. Given the intolerance to CL/spectacles wear, a clear lens extraction with toric IOL implantation was ensued. Preoperative topography revealed an against-the-rule astigmatism of 9D in RE and 16.3D in LE. Based on the biometric/topographic data, monofocal, bitoric IOLs of +14.0+12.00D in RE and +13.0+12.00 in LE were implanted in a sequential approach. Surgeries were uneventful.

Three months later the patient was satisfied with the visual outcome, with a BCVA of 10/10 (-0.75x30º) in RE and 8/10 (-1.50x90º) in LE. Over the next 3 years there as a small increase of cylindrical error with a BCVA of 10/10 (-1.25x30º) in RE and 8/10 (-3.0x90º) in the last visit; binocular uncorrected distance visual acuity was 8/10 (-2). The patient was satisfied with the surgical outcome and no further interventions were planned.

Terrien marginal degeneration induced astigmatism is a clinical challenge. While several approaches have been advocated, primary implantation of a toric IOL in the bag (when disease is stable) leaves room for secondary implant of a toric ICL/IOL in the sulcus, which may be key in cases of very high astigmatism.