Stargardt disease: monitoring incidence and diagnostic trends in the Netherlands using a nationwide disease registry

Purpose

To assess the incidence of Stargardt disease (STGD1) and to evaluate demographics of incident cases.

Methods

For this retrospective cohort study, demographic, clinical and genetic data of patients with a clinical diagnosis of STGD1 were registered between September 2010 and January 2020 in a nationwide disease registry. Annual incidence (2014‐2018) and point prevalence (2018) were assessed on the basis of this registry.

Results

A total of 800 patients were registered, 56% were female and 83% were of European ancestry. The incidence was 1.67‐1.95:1,000,000 per year and the point prevalence in 2018 was approximately 1:22,000‐1:19,000 (with and without 10% of potentially unregistered cases). Age at onset was associated with sex (p = 0.027, Fisher’s exact); 1.9x more women than men were observed (140 versus 74) amongst patients with an age at onset between 10 and 19 years, while the sex ratio in other age‐at‐onset categories approximated one. Late‐onset STGD1 (≥45 years) constituted 33% of the diagnoses in 2014‐2018 compared to 19% in 2004‐2008. Diagnostic delay (≥2 years between the first documentation of macular abnormalities and diagnosis) was associated with older age of onset (p = 0.001, Mann–Whitney). Misdiagnosis for age‐related macular degeneration (22%) and incidental STGD1 findings (14%) was common in patients with late‐onset STGD1.

Conclusion

The observed prevalence of STGD1 in real‐world data was lower than expected on the basis of population ABCA4 allele frequencies. Late‐onset STGD1 was more frequently diagnosed in recent years, likely due to higher awareness of its phenotype. In this pretherapeutic era, mis‐ and underdiagnosis of especially late‐onset STGD1 and the role of sex in STGD1 should receive special attention.

Clinical outcomes of treatment with idebenone in Leber's hereditary optic neuropathy in the Netherlands: A national cohort study

PURPOSE

The purpose of the study was to present results from a national Dutch cohort of patients with Leber's Hereditary Optic Neuropathy (LHON) treated with idebenone.

METHODS

The multicentre, open-label, retrospective evaluation of the long-term outcome of idebenone treatment of Dutch LHON patients on visual function and on thickness of the retinal ganglion cell layer. Patients included in the analysis had a confirmed mutation in their mitochondrial DNA encoding either of the seven subunits of complex I, had a reported loss of vision in at least one eye and had a follow-up of more than 6 months after their treatment was started. Control visits involved routine clinical examinations of visual function and retinal structure at (1) the start of treatment, (2) nadir (time of lowest visual acuity), (3) the time of recovery (if any), (4) the time of termination of treatment and (5) more than 6 months after termination of the treatment.

RESULTS

Data from 72 patients were analysed. Treatment duration was 23.8 ± 14.4 (mean ± SD) months. A positive response, that is either a clinically relevant recovery (CRR) or a clinically relevant stabilization (CRS), occurred in 53% and 11% of the patients, respectively. The magnitude of CRR was 0.41 ± 1.54 logMAR. CRR of visual acuity is associated with recovery of colour discrimination. The thickness of both the ganglion cell complex (GCC) and the retinal nerve fibre layer (RNFL) is irreversibly reduced.

CONCLUSION

Our results confirm that idebenone may help to restore or maintain visual function. Whether this effect will persist is still unknown. Thinning of retinal neural tissue appears to be permanent.

[New treatment option for Leber hereditary optic neuropathy: early diagnosis is required]

BACKGROUND

Leber hereditary optic neuropathy (LHON) is an orphan disease which leads to painless subacute loss of central vision in both eyes. It develops mainly in young adults and is more common in males. It most often leads to lifelong blindness. Idebenone has shown to have a favourable effect in promoting vision recovery in LHON-patients with recent visual impairement.

CASE DESCRIPTION

Two male LHON patients, aged 27 and 54 years of age were misdiagnosed during one year with optic neuritis and conversion disorder. The delay caused unnecessary emotional suffering and took away the opportunity of idebenone treatment. This can be prevented by greater awareness of disease characteristcs and OCT-scanning.

CONCLUSION

Therapy for LHON requires a timely diagnosis.

Impact of upper blepharoplasty, with or without orbicularis oculi muscle removal, on tear film dynamics and dry eye symptoms: A randomized controlled trial

PURPOSE

Upper blepharoplasty may be related to dry eye symptoms since the function of the orbicularis oculi muscle may affect the tear film. We aimed to assess the effect of blepharoplasty with or without the removal of a strip of orbicularis oculi muscle on tear film dynamics and dry eye symptoms.

METHODS

A double-blind, randomized, controlled trial comparing upper blepharoplasty without (group A) or with (group B) orbicularis oculi muscle excision was performed on 54 healthy Caucasian patients. Tear film dynamics and dry eye symptoms were evaluated using multiple dry eye parameters, i.e. tear osmolarity, Schirmer test I, corneal/conjunctival staining, tear break-up time (TBUT), Oxford Scheme, Sicca Ocular Staining Score and Ocular Surface Disease Index questionnaire. All the parameters were assessed preoperatively and 6 and 12 months after upper blepharoplasty. All the groups' outcomes were compared.

RESULTS

The differences were not significant between the two upper blepharoplasty techniques regarding most of the above-mentioned outcomes. Subjective symptoms of ocular irritation, consistent with dry eye disease and vision-related impairment, were reduced after upper blepharoplasty independent of the type of the technique applied, while the pre and postoperative outcomes of the objective tear dynamics did not differ 12 months after surgery. However, group B demonstrated a significant increase in tear osmolarity and TBUT at the 6-month follow-up visit.

CONCLUSION

An upper blepharoplasty alleviates subjective dry eye complaints in the long term, while not changing the tear dynamics. The improvement was independent of the blepharoplasty technique used.

Recognizing differentiating clinical signs of CLN3 disease (Batten disease) at presentation

Purpose

To help differentiate CLN3 (Batten) disease, a devastating childhood metabolic disorder, from the similarly presenting early‐onset Stargardt disease (STGD1). Early clinical identification of children with CLN3 disease is essential for adequate referral, counselling and rehabilitation.

Methods

Medical chart review of 38 children who were referred to a specialized ophthalmological centre because of rapid vision loss. The patients were subsequently diagnosed with either CLN3 disease (18 patients) or early‐onset STGD1 (20 patients).

Results

Both children who were later diagnosed with CLN3 disease, as children who were later diagnosed with early‐onset STGD1, initially presented with visual acuity (VA) loss due to macular dystrophy at 5–10 years of age. VA in CLN3 disease decreased significantly faster than in STGD1 (p = 0.01). Colour vision was often already severely affected in CLN3 disease while unaffected or only mildly affected in STGD1. Optic disc pallor on fundoscopy and an abnormal nerve fibre layer on optical coherence tomography were common in CLN3 disease compared to generally unaffected in STGD1. In CLN3 disease, dark‐adapted (DA) full‐field electroretinogram (ERG) responses were either absent or electronegative. In early‐onset STGD1, DA ERG responses were generally unaffected. None of the STGD1 patients had an electronegative ERG.

Conclusion

Already upon presentation at the ophthalmologist, the retina in CLN3 disease is more extensively and more severely affected compared to the retina in early‐onset STGD1. This results in more rapid VA loss, severe colour vision abnormalities and abnormal DA ERG responses as the main differentiating early clinical features of CLN3 disease.

[A man with acute decline in vision and sleep apnoea]

BACKGROUND

Non-arteritic anterior ischaemic optic neuropathy (NAION) is the most common acute optic neuropathy in people older than 50 years.

CASE DESCRIPTION

A 66-year-old man with hypertension consulted the ophthalmologist because of increasing visual-field loss in his right eye; 3 weeks previously he had noticed visual decline in the same eye when he woke up. The eye was not painful. Further questioning revealed that the patient also suffered from sleep apnoea. Following additional investigations we diagnosed NAION.

CONCLUSION

There is no effective treatment for NAION. Risk factors such as high blood pressure and obstructive sleep apnoea syndrome can be addressed to reduce the risk of reoccurrence of NAION in the other eye.

The prevalence of microcystic macular changes on optical coherence tomography of the macular region in optic nerve atrophy of non-neuritis origin: a prospective study

BACKGROUND

Microcystic macular changes, also called microcystic macular oedema, have recently been reported in patients with multiple sclerosis, particularly after optic neuritis. But it has since emerged that the finding is not specific for optic neuritis. This study was designed to prospectively investigate the prevalence of microcystic perifoveal changes in patients with optic atrophy not due to optic neuritis.

METHODS

A prospective, cross-sectional study including 54 patients with a history of optic atrophy and 54 healthy control subjects. Spectral domain optical coherence tomography (SD-OCT) was used to scan the macular area and to measure the peripapillar retinal nerve fibre layer thickness. Scanning laser ophthalmoscopy (SLO) was used for imaging of the macular area.

RESULTS

Microcystic macular changes were present in 11/54 patients (20.4%), 17/90 eyes with optic atrophy (18.9%) and absent in the normal eyes of patients with monocular optic atrophy and all healthy control eyes. No correlations were found with the age, duration of optic atrophy or severity of optic atrophy. Besides the known perifoveal (semi) circular abnormal reflexes on SLO imaging, we also noticed a more patchy pattern of low SLO reflections in some patients with optic atrophy.

CONCLUSIONS

Microcystic macular changes are a frequent observation in patients with optic atrophy of another cause than optic neuritis. The cause of these abnormalities remains a matter of debate. It is important for clinicians to recognise these macular changes and to realise that the cause may lie remotely away from the macula.

Novel membrane frizzled-related protein gene mutation as cause of posterior microphthalmia resulting in high hyperopia with macular folds

PURPOSE

We present a genetic and clinical analysis of two sisters, 3 and 4 years of age, with nanophthalmos and macular folds.

METHODS

Ophthalmological examination, general paediatric examination and molecular genetic analysis of the MFRP gene were performed in both affected siblings.

RESULTS

Clinical analysis showed high hyperopia (+11 D and +12 D), short axial lengths (15 mm) and the presence of macular folds and optic nerve head drusen. Autofluorescence of the retina was generally normal with subtle macular abnormalities. Sequence analysis showed compound heterozygosity for severe MFRP mutations in both sisters: a previously reported p.Asn167fs (c.498dupC) and a novel stop codon mutation p.Gln91X (c.271C>T).

CONCLUSION

These are the youngest nanophthalmos patients in the literature identified with severe loss of MFRP function, showing already the known structural abnormalities for this disease. Adult patients affected by homozygous or compound heterozygous MFRP mutations generally show signs of retinal dystrophy, with ERG disturbances and RPE abnormalities on autofluorescence imaging. ERG examination could not be performed in these children, but extensive RPE abnormalities were not seen at this young age.

Leber’s hereditary optic neuropathy and vitamin B12 deficiency

BACKGROUND

Leber's hereditary optic neuropathy (LHON) is a maternally inherited optic neuropathy caused by mutations in mitochondrial DNA (mtDNA). It is also believed that several epigenetic factors have an influence on the development of LHON.

METHODS

A case series was observed.

RESULTS

Three patients who developed bilateral optic neuropathy are presented. All patients had a primary LHON mutation in their mtDNA, but also a subnormal vitamin B12 serum level at the time of presentation.

CONCLUSIONS

The clinical picture of optic neuropathy associated with vitamin B12 deficiency shows similarity to that of LHON. Both involve the nerve fibres of the papillomacular bundle. The present case reports suggest that optic neuropathy in patients carrying a primary LHON mtDNA mutation may be precipitated by vitamin B12 deficiency. Therefore, known carriers should take care to have an adequate dietary intake of vitamin B12 and malabsorption syndromes like those occurring in familial pernicious anaemia or after gastric surgery should be excluded.

Cyclic esotropia and the treatment of over-elevation in adduction and V-pattern

AIM

To describe the development and treatment of V-pattern and bilateral over-elevation in adduction in patients with cyclic esotropia.

METHODS

Three patients with cyclic esotropia are described in retrospect. All patients underwent bilateral medial recession, while one patient additionally had a weakening procedure of both inferior oblique muscles.

RESULTS

All patients developed a V-pattern and bilateral over-elevation in adduction. After strabismus surgery, normal eye alignment with some signs of binocularity was reached in all three patients. Moreover, the over-elevation in adduction and V-pattern completely resolved.

CONCLUSIONS

V-pattern and bilateral over-elevation in adduction was seen in all patients with cyclic esotropia in the stage that fusion was disrupted. Possible explanations for the origin of these patterns are discussed. Strabismus surgery aimed to correct the horizontal esotropic angle restored fusion and eliminated the vertical incommitancies in lateral gaze, and the V-pattern.

Radiation optic neuropathy after external beam radiation therapy for acromegaly: report of two cases

For diagnosing radiation optic neuropathy (RON) ophthalmological and imaging data were evaluated from 63 acromegalic patients, irradiated between 1967 and 1998. Two patients developed RON: one patient in one optic nerve 10 years and another patient in both optic nerves 5 months after radiation therapy. RON is a rare complication after external beam radiation therapy for acromegaly, which can occur after a considerable latency period.

The polaroid suppression test in a pediatric population with ophthalmologic disorders

PURPOSE

The Polaroid suppression test (PST) is a new method for early detection of amblyogenic factors by screening for suppression. The apparatus can elicit suppression with the use of Polaroid filters. The aim of the present study was to examine a population of children with known ophthalmologic disorders using the PST to determine the rate of false-negative results of the PST.

METHODS

Six hundred four children, varying in age between 3 and 15 years (mean, 7.9) were examined using the PST. Ophthalmologic disorders ranged from strabismus and amblyopia to refractive disorders.

RESULTS

Mean testing time for the PST was 43 seconds. The PST could not be administered to 34 children (5.6%); 443 children (73.3%) had abnormal results; and 127 children (22.2%) showed no suppression. The suppression in constant strabismus was detected in almost all cases. The sensitivity for accommodative forms of strabismus was lower, but amblyopia was never missed in these cases. In children with normal eye alignment, only 2.7% with an interocular acuity difference of more than 0.1 logMAR had no suppression. Of all 119 children with clinical defined amblyopia, only 1 (0.8%) did not have suppression. Overall sensitivity of the PST for strabismus and/or abnormal interocular acuity difference was 96.2% and specificity was 41.1%.

CONCLUSIONS

The PST has great potential as a visual screening tool in young children. Only few children with amblyogenic factors were missed. Thus, the test can differentiate those children at risk for amblyopia from normally sighted children. Because specificity is lower, all children showing suppression with the PST in a screening situation should have further examination by the health care worker before being referred to the ophthalmologist.

Chiasmal coefficient of flash and pattern visual evoked potentials for detection of chiasmal misrouting in albinism

The diagnosis of albinism can be confirmed by electrophysiological examination, when chiasmal misrouting can be demonstrated. The present study describes a quantitative analysis method for this purpose. A chiasmal coefficient (CC) was calculated by correlating the differential potential over left and right hemisphere, when stimulating left versus right eye. This CC will be negative in albinism and positive in normal individuals. VEPs were recorded in 20 control subjects, four children with congenital motor nystagmus and six children with albinism. In up to 25% of the controls the CC was negative, when using flash VEP. However, with pattern VEP all had a positive CC. All children with albinism had a negative CC. Three of the four patients with congenital motor nystagmus had a positive CC, and one child had a small negative value with flash stimulation. In conclusion, determination of CC is a valuable and objective analysis method for electrophysiological determination of chiasmal misrouting. The method is relatively simple and only needs two electrode tracings. One should be aware of false-positive results when using flash stimulation. Whenever possible pattern stimulation should be used.