Optic Nerve Head Drusen: The Relationship Between Intraocular Pressure and Optic Nerve Structure and Function.

OBJECTIVE: To determine whether at the time of diagnosis, the intraocular pressure (IOP) in patients with optic nerve head drusen (ONHD) correlates with the perimetric mean deviation (PMD) and the mean retinal nerve fiber layer (RNFL) thickness on optical coherence tomography (OCT). METHODS: This retrospective chart review included adults with ONHD from 2 academic medical centers. Inclusion criteria were age older than 18 years, definitive diagnosis of ONHD, measurement of IOP, and an automated visual field (VF) within 3 months of diagnosis. Exclusion criteria were unreliable VFs, use of IOP-lowering therapy, and visually significant ocular comorbidities. Data were collected from the initial visit. Age, IOP, method of diagnosis of ONHD, mean RNFL thickness, and PMD were recorded. Multiple and logistic regression models were used to control for potential confounders in statistical analyses. RESULTS: Chart review identified 623 patients, of which 146 patients met inclusion criteria. Mean age was 44.2 years (range: 19-82 years). Average PMD of 236 eyes was -5.22 dB (range, -31.2 to +1.21 dB). Mean IOP was 15.7 mm Hg (range: 6-24 mm Hg). Forty eyes (16.9%) underwent RNFL measurement using OCT; mean RNFL thickness was 79.9 µm (range: 43-117 µm). There was no statistically significant association between IOP and PMD (P = 0.13) or RNFL thickness (P = 0.65). Eyes with ocular hypertension tended to have less depressed PMD than those without (P= 0.031). Stratified analyses of visible and buried subgroups yielded similar results. CONCLUSIONS: Lowering IOP in patients with ONHD has been proposed as a means to prevent progression of optic neuropathy. Our study demonstrated that among predominately normotensive eyes, higher IOP was not associated with greater VF loss or thinner RNFL at the time of presentation. This suggests that lowering IOP may not be beneficial in preventing visual loss in normotensive eyes with ONHD.

Leber Hereditary Optic Neuropathy: Visual Recovery in a Patient With the Rare m.3890G>A Point Mutation.

A 15-year-old boy experienced painless vision loss in the left eye of unknown duration. Leber hereditary optic neuropathy (LHON) was suspected, despite negative testing for the 3 most common pathogenic gene mutations and idebenone 300 mg 3 times daily was prescribed. Nine months later, the patient developed right eye involvement. Complete mitochondrial genome analysis revealed 2 rare variants-m.3890G>A of the MT-ND1 gene and m.8417C>A of the MT-ATP8 gene. The former has been described in severe infantile Leigh syndrome and LHON; the latter is of unknown significance. The patient experienced progressive visual deterioration through 12 months, but improved to 20/20, right eye and 20/25, left eye, at 21 months. Visual recovery can occur in a patient with bilateral optic neuropathy secondary to the rare m.3890G>A point mutation.