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Dr.SHABARI PAL,Dr.VAIBHAV KUMAR JAIN,Dr.Vikas Kanaujia,Dr.Kumudini Sharma

Abstract

Purpose: To evaluate the corneal biomechanical properties in patients who underwent kidney transplant and to compare them with healthy age matched control

Methods: In this cross-sectional study, 68 patients with kidney transplant (study group) and 68 healthy subjects (control group) underwent Ocular Response Analyzer measurements. Only right eye of a subject was assessed for Corneal hysteresis (CH), corneal resistance factor (CRF),corneal compensated intraocular pressure(IOPcc), Goldmann correlated intraocular pressure (IOPg).

Results:  Mean CH in study group was 9.70±1.62 mm Hg which was significantly lower than control group with mean CH of 10.60±1.49 mm Hg (P=0.001). Mean IOPcc was 18.17± 4.00 mm Hg and 16.00±3.94 mm Hg in study and control group, respectively (P=0.002). CRF and IOPg were not significantly different between groups.

Conclusion: CH and IOPcc are altered in kidney transplant patients so they should be considered in evaluation for glaucoma.

Keywords: Kidney transplant; ORA (ocular response analyzer); corneal biomechanical; Corneal hysteresis; corneal resistance factor 

Introduction

Kidney transplantation is indicated in patients with chronic kidney disease (stage 5 or stage 4) with progressive disease. 1,2  Commonly used immunosuppressive agents in renal transplant patients are corticosteroids, cyclosporin, tacrolimus, mycophenolate mofetil, azathioprine and sirolimus.3 Long-term corticosteroid use has been known to affect intraocular pressure (IOP). Also, biomechanical characteristics of the cornea like central corneal thickness (CCT)4, corneal hysteresis (CH)5 have been known to be related to intraocular pressure measurements and the risk of glaucoma progression.

The Ocular Response Analyzer (ORA) is a non-contact differential tonometer which measures IOP and corneal viscoelasticity in vivo.6Renal transplant patients are on maintenance immunosuppression over a prolonged duration. The changes in corneal biomechanical properties in this subset of patients has never been previously studied. This study thus aims to analyze the effect of the corneal biomechanical parameters on IOP measurement and evaluation of glaucoma in these patients requiring prolonged corticosteroid administration.

Materials and methods

Renal transplant patients > 18 years of age undergoing routine follow-up visits at the Nephrology Department of our institute were recruited for the study. These patients underwent complete ophthalmological assessment including ORA measurements.

In this cross-sectional study 68 patients who underwent kidney transplant (study group) and 68 healthy age-matched subjects (control group) were recruited over a duration of 1 year. Patients with corneal disorders, glaucoma, and retinal disorders were excluded.

Informed consent was obtained from all subjects and data was obtained with respect to age, sex and duration of corticosteroid use in the study subjects. Only the right eye of all subjects was assessed for Corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc), Goldmann correlated intraocular pressure (IOPg).

Anterior and posterior segment evaluation was done using slit-lamp biomicroscopy, slit- lamp biomicroscopy with +90 D lens and indirect ophthalmoscopy respectively.

Results

The mean age in study group was 38.76±9.19 years.   Mean CH in the study group was 9.70±1.62 mm Hg which was significantly lower than control group with mean CH of 10.60±1.49 mm Hg (P=0.001). Mean IOPcc was 18.17± 4.00 mm Hg and 16.00±3.94 mm Hg in study and control group, respectively (P=0.002). CRF (10.44±1.83 mm Hg in study group and 10.85±1.75 mm Hg in control group), and IOPg (17.07±4.19 mm Hg in study group and 16.42±4.22 mm Hg in control group) were not significantly different between the two groups.

Discussion  

The role of corneal biomechanical properties has been studied in various settings as earlier studies have shown that it may be associated with glaucoma diagnosis, progression, refractive surgeries.7 They have been altered in systemic diseases like systemic lupus erythematosus, rheumatoid arthritis, scleroderma, and collagen vascular disorders.8-11

Kidney transplant patients have complex multifactorial systemic alterations which may affect corneal biomechanical properties. Patients on routine dialysis before kidney transplantation, and on multiple immunosuppressive agents like corticosteroid, tacrolimus, mucophenolate mofetil, azathioprine post transplant may affect corneal biomechanical properties. Corneal biomechanical properties have become a very important factor to consider particularly in these patients as they susceptible to risk of steroid induced glaucoma due to the prolonged steroid therapy in most of these patients. We found lower CH in our kidney transplant patients compared to controls which has been shown as an independent risk factor for glaucoma diagnosis and management.  Also a higher IOPcc in kidney transplant patients shown in our study should be considered. These could be due to the prolonged steroid usage in kidney transplant patients.

In conclusion, the corneal biomechanical properties must be considered while evaluating kidney transplant patients.

References

  1. Dudley C, Harden P. Renal Association Clinical Practice Guideline on the assessment of the potential kidney transplant recipient. Nephron Clin Pract. 2011;118:209-24.
  2. Guidelines for Living Donor Kidney Transplantation United Kingdom Guidelines.; 2018. www.bts.org.uk. Accessed October 13, 2018.
  3. Thiruchelvam PTR, Willicombe M, Hakim N, Taube D, Papalois V. Renal transplantation. BMJ. 2011. doi:10.1136/bmj.d7300
  4. Gordon MO, Beiser JA, Brandt JD, et al. The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. Arch Ophthalmol (Chicago, Ill 1960). 2002;120:829-30.
  5. Congdon NG, Broman AT, Bandeen-Roche K, Grover D, Quigley HA. Central Corneal Thickness and Corneal Hysteresis Associated With Glaucoma Damage. Am J Ophthalmol. 2006;141:868-875.
  6. Luce DA. Determining in vivo biomechanical properties of the cornea with an ocular response analyzer. J Cataract Refract Surg. 2005;31(1):156-162.
  7. Deol M, Taylor DA, Radcliffe NM. Corneal hysteresis and its relevance to glaucoma. Curr Opin Ophthalmol 2015;26:96-102.
  8. Yazici AT, Kara N, Yuksel K, Altinkaynak H, Baz O, Bozkurt E, Demirok A. The biomechanical properties of the cornea in patients with systemic lupus erythematosus. Eye (Lond) 2011;25:1005-9.
  9. Can ME, Erten S, Can GD, Cakmak HB, Sarac O, Cagil N. Corneal biomechanical properties in rheumatoid arthritis. Eye Contact Lens 2015;41:382-5.
  10. Emre S, Kayikcioglu O, Ates H, Cinar E, Iceoglu N, Yargucu F, Pirildar T, Oksel F. Corneal hysteresis, corneal resistance factor, and intraocular pressure measurement in patients with scleroderma using the reichert ocular response analyzer. Cornea 2010;29:628-31.
  11. Colaco ML, Franco M, Pinto R, Seco JM. Corneal structure and biomechanics in collagen vascular diseases. Oftalmologia 2014;38:243-7.

 

 

 

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