Effect of Ocular Biomechanics on Intraocular Pressure Measurement in Mucopolysaccharidosis I-S (Scheie’s Syndrome)

Purpose: To study the effect of biomechanical properties of the cornea on the intraocular pressure in eyes affected with Mucopolysaccharidosis type I-S (Scheie's syndrome). Methods: Four eyes of two patients in their mid-fifties diagnosed with Scheie's syndrome were investigated for corneal biomechanical properties. The corneal biomechanical profile was assessed by the use of Ocular response analyzer (ORA, Reichert Inc., of Buffalo, NY). Intraocular pressures were also checked using various tonometry devices to check for variability in the readings due to the corneal changes. Results: The intraocular pressure (IOP) measurements were noted to be high in both the patients at their initial presentation. Both the patients were put on topical anti glaucoma treatment and one underwent glaucoma filteration surgery as well for IOP control. Both the patients underwent successful bilateral deep anterior lamellar keratoplasty (DALK) procedures. The post procedure IOP measurement had a dramatic improvement in both the patients. Corneal biomechanical profile was noted to be high pre DALK and reduced significantly after the lamellar surgery. The intraocular pressure readings were also measured using different tonometry devices and were noted to be lower after graft surgeries. Conclusion: Corneal rigidity and hysteresis is high in patients with MPS type I-S. This is reflected in the raised intraocular pressures checked by use of applanation or indentation tonometry. Use of the ocular response analyzer has helped study the biomechanical properties of such corneas and helped in assessment of true values of intraocular pressures thus preventing inappropriate intervention options especially surgical options.