# Ophthalmic Manifestation in Neurofibromatosisosis Type 2
## 4 Discussion
Specifically, five of our patients (35.7%) presented cataractact, and two patients (14.3%) already underwent cataract surgery, amounting to seven patients (50%). Considering the young age of five of these seven patients, the development of cataract in their case can be plausibly attributed to NF2. We can underline that these patients presented a posterior subcapsular cataract, which is the form most frequently associated with the disease [15]. The other two patients with cataracts were, respectively 73 and 78 years old and the age of onset was not clear from the history, therefore it cannot be safely stated that the lens opacities in these patients are caused by NF2 or senile age. Epiretual membranes were the second most common sign in our sample after cataracts (28.6% of patients). ERMs in NF2 patients, at OCT evaluation, have atypical and distinctive characteristics, such as edges that project anteriorly into the vitreous despite an incomplete posterior vitreous detachment, a lack of cystoid macular edema, and an irregular and partially absent ILM [16]. These features distinguish it from idiopathic ERM or membranes associated with other diseases [16; 17; 18]. Histopathological studies highlighted that these abnormalities consist mainly of a mixture of Muller cells and astrocytes [19], supporting the hypothesis that ERMs represent hamardomas composed of Muller cells and justifying their morphological appearance [16]. OCT is the most sensitive method for studying this type of lesion and has allowed us to detect forms of various degrees: one of grade 0, one of grade 1, and four of grade 2 (macular pucker), according to the Gass classification [20]. Two young patients with macular pucker, aged 16 and 37, also showed subcapsular cataracts. The 16-year-old patient, as previously mentioned, was affected by a severe form of NF2. This observation agrees with several authors who showed a direct relationship between the prevalence of NF2-specific eye findings, the age of onset, and the severity of the genetic defect [8; 9]. Another relevant finding detected in 21.4% of our patients were retinal tufts. This percentage appears to be inferior when compared with the recent literature. In a case-control study, [PERSON] et al. reported retinal tufts as the most common abnormalities of the central retina in 23 patients (43%), principally observed in patients with a severe form and not seen in controls, therefore showing a positive predictive value of 100% [21]. This difference can be explained because most of our patients have a mild form of the disease, as mentioned above. Interestingly, [PERSON] et al. reported the presence of choroidal abnormalities in NF2 patients. Choroidal abnormalities, visible as multiple, bright, patchy nodules in near-infrared reflectance (NIR) OCT, have recently been added to the revised diagnostic criteria for neurofibromatosisis type 1 based on their high specificity and sensitivity [22]. In our sample, we have not found compatible lesions. Further studies on choroidal characterization in NF2 are needed [23; 24]. As already mentioned, other ocular manifestations associated with NF2 are papilledema, optic atrophy, neurotrophic keratopathy, corneal keratitis and opacity, and ocular and eyelid motility disorders [9]. Among the non-specific ocular manifestations in our patients, we found changes affecting the cornea, eyelids, extrinsic muscles of the eye, and the optic nerve. We highlighted eyelid ptosis in two patients (14.3%), lagophthalmos in four patients (28.6%), and strabismus in seven patients (50%). Eyelid ptosis is reported by [PERSON] and other authors as a secondary manifestation of NF2, resulting from hypofunction of the oculomotor nerve [25]. Lagophthalmos is generally linked to post-surgical facial paralysis, following the removal of acoustic schwannomas. [9] This clinical feature was observed in our patients as a consequence of post-surgical VII nerve paralysis.