A Confocal Microscopy Study of the Keratoconic Cornea Stroma in a Malaysian Ophthalmology Centre

1. Rohanah Alias¹
2. Shamala Retnasabapathy²
3. Thiageswari Umapathy¹

¹Ophthalmology Department, Hospital Kuala Lumpur, Malaysia
²Opthalmology Department Hospital Sungai Buloh

Purpose: a) To determine the prevalence of slit lamp biomicroscopy corneal signs.
b) To compare the corneal stromal thickness and keratocyte density between keratoconus and normal patients c) To determine the association of the corneal stromal thickness and keratocyte density with the severity of keratoconus.

Design: Cross sectional.

Methods: Fifty patients with keratoconus and thirty normal individuals attended Hospital Kuala Lumpur were recruited. Each keratoconus case underwent slitlamp examinations, corneal topography, and confocal microscopy examination. Normal individuals underwent slit lamp examination and confocal microscopy examination.

Results: Fifty keratoconus patients, mean age was 22.50±7.58, were mainly males 64% and Indians 66%. 60% of the patients had severe keratoconus and 80% of them were Indians. Prevalence of the corneal signs were Vogt's striae 50%, Fleischer's ring 66%, corneal scar 14% and prominent corneal nerve 72%. Corneal stromal thickness was thinner in keratoconus (401.19±59.52µm) than normal group (482±43.79 µm) p<0.005. There was no significant difference in corneal stromal thickness between the severities of keratoconus group. Mean keratocyte density in the keratoconus compared to normal group in anterior stroma was 865.52±94.51 (vs1032.58±88.31cell/mm2 (p<0.005)) ,mid stroma 774.03±92.37(vs 949.92±68.96 cell/mm2 (p<0.005)) and posterior stroma 699.41±114.48 (vs 888.45±62.68 cell/mm2 (p<0.005)). There was a significant difference of keratocyte density in anterior stroma (p=0.004), mid stroma (p=0.005) and posterior stroma (p=0.001) between the severities of keratoconus group.

Conclusions: Severe keratoconus had all the corneal signs of keratoconus . Keratoconus had thin corneal stroma and decreased keratocyte density. Severe keratoconus had more decreased keratocyte density than mild and moderate keratoconus.