Abstract
Purpose: :
To determine the corneal thickness, curvature and anterior chamber depth in known and suspected cases of Marfan syndrome (MFS), in order to evaluate the predictive value of these properties in suspected MFS.
Methods: :
Prospective, clinical case series. Patients were categorised into definitive MFS, suspected MFS (using the Ghent criteria), and an age-matched control group. Dilated Slit Lamp examination was undertaken to detect ectopia lentis. Corneal topography was performed using Orbscan system I and Pentacam Scheimpflug Camera, with mean keratometry, corneal thickness, and anterior chamber depth (ACD) calculated. The suspected MFS group were further subdivided on the presence of Ectopia Lentis, and Cardiovascular system involvement.
Results: :
Forty-five patients (90 eyes) referred with a definitive or suspected diagnosis of MFS were recruited. 13 patients met the definitive criteria, 32 patients had suspected MFS, and 50 subjects were in the control group. The mean age [±SD] of the definitive Marfan group was 29 yrs [±15.6], and 28yrs [±12.7], and 31 yrs [±5.4] in the suspected MFS and control group respectively. [p=0.5]. No significant difference was observed between Orbscan and Pentacam measurements. (p=0.28). There was no significant difference in corneal thickness between the Definitive MFS group and the suspected MFS group compared with controls [p= 0.1, 0.07 respectively]. Corneal curvature determined by average Ks in the definitive MFS group was 40.95 diopters [D] and this was statistically significant compared with controls [average Ks= 42.89 (p= 0.0007).] Comparing the suspected MFS subgroup (ectopia lentis with one major criteria) [Ks=41 D] with controls the result was significant p=0.0013. Similarly, corneal curvature in suspected MFS subgroup - cardiovascular involvement with one major criteria [ Ks=40.94], compared with controls was also significant p=0.0001. Mean ACD [±SD] in the definitive MFS was 3.64 [±0.34] mm compared with controls 3.55[±0.4] but was not statistically significant p=0.2934. Statisitical analysis using a ROC curve showed a corneal curvature of less than 42D has 80% sensitivity and 80% specificity to detect MFS.
Conclusions: :
Keratometry values determined by Orbscan and Pentacam topography in both definitive MFS and suspected Marfan syndrome are significantly flatter when compared with the control group. Moreover this result was highly significant in the suspected group so this highlights the importance of the Ks value as an index in the diagnosis of MFS.
Keywords: cornea: clinical science • genetics • topography