LENTICONUS ANTERIOR AND LENTICONUS POSTERIOR : RARE OCULAR MANIFESTATIONS: 2 CASE REPORTS

   Lenticonus is a bulging of the lens capsule and the underlying cortex. The diagnosis of lenticonus is essentially a clinical diagnosis which is made by biomicroscopic examination. According to the localization of the conus a distinction is made between lenticonus anterior and lenticonus posterior. 

 A case report of two patients, the first one suffering from lenticonus anterior associated with Alport’s syndrome and the second one from lenticonus posterior without any systemic manifestations.

Case 1 :    A 24‑year‑old male, with Alport syndrome presented for progressive loss of vision in both eyes , On ocular examination, his best corrected visual acuity was 04/10 on the right eye, and 2/10 on the left eye. Refraction showed high myopia -15.50 (-2.00 à 50) in the right eye and -17.25 (-2.25à140°) in the left eye.   Slit lamp examination revealed conical protrusion of anterior surface of crystalline lens suggestive of anterior lenticonus in both eyes. Fundus was normal. Clear lens extraction operation was proposed but the patient refused the surgery.

Case 2 : A 30-year-old female, with no medical history, presented for history of poor vision, eye examination revealed her best corrected visual acuity was 02/10 on the right eye, and 10/10 on the left eye. Refraction showed -3,5D (-4,00 à 50°) in the right eye and  (-0,50 à 50°). Slit lamp examination revealed a posterior protrusion of the lens, extending towards the vitreous chamber The rest of the eye examination was unremarkable.

Lenticonus anterior was first described by Webster (1874). It is characterised by a regular, welldefined conical or more globular protrusion of the anterior part of the lens into the chamber. Catarct often occurs together with lenticonus anterior.The cause of lenticonus anterior is unknown. Theories are numerous. Amongst the most important can be mentioned : Development abnormality, a toxic metabolite, inflammation, and trauma.  Posterior lenticonus is a circumscribed round or oval bulge of the posterior lens capsule and cortex . It is a rare condition and had been known since described by Meyer in 1888. It may usually presents as the only ocular anomaly and generally unilateral or it may be bilateral .The pathogenesis of the anomaly is mainly due to inherited thinning and weakness of the central part of the posterior lens capsule, visual loss may be secondary to the development of the cataractous changes or to The high refractive errors, mostly myopic.

We concluded from the clinical study of these two cases and from reviewing the reported cases in the literature that ophthalmologists should be careful in examining patients with Alport syndrome and should remain alerted to the possibility of the presence of posterior lenticonus or the potential of anterior lenticonus to progress into posterior lenticonus.