OPTICAL COHERENCE TOMOGRAPHIC FEATURES OF PAPILLOMACULAR FOLD IN POSTERIOR MICROPHTHALMOS

Genetic analysis assists diagnosis of clinical systemic disease in children with excessive hyperopia

Background

A thorough examination (especially those including visual functional evaluation) is very important in children’s eye-development during clinical practice, when they encountered with unusual excessive hyperopia especially accompanied with other possible complications. Genetic testing would be beneficial for early differential diagnosis as blood sampling is more convenient than all other structural imaging capture tests or functional tests which need children to cooperate well. Thus genetic testing helps us to filter other possible multi-systemic diseases in children patients with eye disorder.

Case presentation

A 3-year-old and an 8-year-old boy, both Chinese children clinically manifested as bilateral excessive hyperopia (≥+10.00), severe amblyopia and exotropia, have been genetically diagnosed as Senior-Loken syndrome-5 (SLSN5) and isolated posterior microphthalmos (MCOP6), respectively.

Conclusions

This report demonstrates the importance of genetic diagnosis before a clinical consult. When children are too young to cooperate with examinations, genetic testing is valuable for predicting other systemic diseases and eye-related development and for implementing early interventions for the disease.

Foveal structure and visual function in nanophthalmos and posterior microphthalmos

BACKGROUND/AIMS

The reason for visual impairment in patients with nanophthalmos and posterior microphthalmos is not completely understood. Therefore, this study aims to investigate foveal structure, and the impact of demographic, clinical and imaging parameters on best-corrected visual acuity (BCVA) in these conditions.

METHODS

Sixty-two eyes of 33 patients with nanophthalmos (n=40) or posterior microphthalmos (n=22), and 114 eyes of healthy controls with high-resolution retinal imaging including spectral-domain or swept-source optical coherence tomography images were included in this cross-sectional case-control study. Foveal retinal layer thickness was determined by two independent readers. A mixed-effect model was used to perform structure-function correlations and predict the BCVA based on subject-specific variables.

RESULTS

Most patients (28/33) had altered foveal structure associated with loss of foveal avascular zone and impaired BCVA. However, widening of outer nuclear layer, lengthening of photoreceptor outer segments, normal distribution of macular pigment and presence of Henle fibres were consistently found. Apart from the presence of choroidal effusion, which had significant impact on BCVA, the features age, refractive error, axial length and retinal layer thickness at the foveal centre explained 61.7% of the variability of BCVA.

CONCLUSION

This study demonstrates that choroidal effusion, age, refractive error, axial length and retinal layer thickness are responsible for the majority of interindividual variability of BCVA as well as the morphological foveal heterogeneity in patients with nanophthalmos or posterior microphthalmos. This might give further insights into the physiology of foveal development and the process of emmetropisation, and support clinicians in the assessment of these disease entities.

Posterior segment abnormalities in posterior microphthalmos

Purpose

We report a case of posterior microphthalmos with characteristic papillomacular retinal folds, pigmentary retinopathy, and optic disc drusen.

Observations

A 19-year-old female presented with decreased visual acuity and was found to have bilateral posterior microphthalmos with the presence of papillomacular retinal folds, crowded optic nerves with buried disc drusen, and peripheral retinal pigmentary changes. Optical coherence tomography showed presence of retinal folds involving the inner retinal layers and loss of foveal contour.

Conclusions and Importance

Posterior microphthalmos can present with an array of unique clinical findings involving the posterior segment. It is important to recognize these findings as these patients often have decreased visual acuity and are at risk for the development of other posterior complications.

Posterior microphthalmos with good visual acuity: A case report

Purpose

We report the case of an 11-year-old boy with posterior microphthalmos who exhibited normal and age appropriate development of visual acuity.

Observations

At the initial diagnosis, when he was 3 years old, the best-corrected visual acuity (BCVA) was 20/125 in the right eye (OD) and 20/200 in the left eye (OS) with high hyperopia (cycloplegic refraction +15.75 D sphere OD and +16.25 D sphere OS). Eight years after he began wearing hyperopic glasses, BCVA was 20/16 OD and 20/20 OS. Optical coherence tomography did not reveal a foveal pit in either eye throughout the observation period. However, elongation of the outer segment and widening of the outer nuclear layers were observed.

Conclusion and Importance

Many cases of posterior microphthalmos demonstrate subnormal BCVA due to an abnormal foveal structure (papillomacular retinal folds, absence of the foveal pit and avascular zone) and high hyperopia. However, if foveal maturity progresses, even if the foveal structure is abnormal, early aggressive amblyopia treatment can result in normal and age appropriate development of visual acuity.

Multimodal imaging in posterior microphthalmos

Purpose

To evaluate the multimodal imaging including optical coherence tomography angiography (OCTA) findings in patients with posterior microphthalmos (PM).

Methods

In an observational case series, four eyes of two patients, eight and twenty-three years old, with clinical proven PM underwent complete ophthalmic examination, including refraction, fluorescein angiography, optical coherence tomography (OCT), OCTA, B-scan ultrasonography, axial length measurement using IOL Master optical measuring, and Pentacam evaluation.

Results

Both patients were high hyperopic with partial thickness retinal fold in macula, retinoschisis, and foveal hypoplasia. Axial length was less than 17 mm with scleral thickening in all eyes. OCTA showed absence of foveal avascular zone (FAZ) in both superficial and deep capillary plexuses. Pentacam showed corneal steepness, shallow anterior chamber, and low anterior chamber volume.

Conclusion

OCTA findings showed absence of avascular zone in both superficial and deep capillary plexuses, while OCT shows partial thickness retinal fold and retinoschisis.

Retinal structural and vascular changes in posterior microphthalmos

BACKGROUND

Posterior microphthalmos (PM) is a rare developmental disorder characterised by high hyperopia, short axial length, presence of retinal papillomacular fold and relatively normal anterior segment findings. The study objective is to describe the retinal structural and vascular changes in eyes with PM with spectral domain optical coherence tomography, optical coherence tomography angiography and multicolour imaging.

METHODS

In this retrospective, comparative case series, 10 eyes of five patients with PM as cases and 10 eyes of five age- and sex-matched controls were included. Structural changes, namely inner and outer retinal layer thicknesses, were measured using optical coherence tomography. Multicolour imaging findings were noted. Perifoveal vascular changes with qualitative and quantitative assessments were analysed using optical coherence tomography angiography.

RESULTS

The foveal dip was absent in all 10 eyes (100 per cent) with PM. There was an elevated retinal papillomacular fold in six eyes (60 per cent) and intraretinal cystoid spaces in two eyes (20 per cent) with PM. The inner retinal layers were thicker in PM. On multicolour imaging, foveal avascular zone and retinal wrinkles were identified in eyes with retinal papillomacular fold in blue and green reflectance images. Perifoveal vascular changes in optical coherence tomography angiography included foveal area size reduction in superficial and deep vascular networks. The foveal capillary vessel densities were higher in PM compared to the controls in both superficial (46.3 ± 3.7 per cent; p = 0.000) and deep (54.7 ± 3.5 per cent; p = 0.000) capillary plexuses. Flow areas in superficial (p = 0.693) and deep (p = 0.088) capillary plexuses were not statistically relevant.

CONCLUSION

The study suggests that in PM, retinal foreshortening occurs in one meridian leading to secondary changes such as loss of foveal dip, posterior bowing of the outer layers of the eye, thickening of the inner retina and ultimately, retinal papillomacular fold formation. The findings of the study need further validation in a larger series of patients with PM.

Biometric and molecular characterization of clinically diagnosed posterior microphthalmos

PURPOSE

To biometrically and molecularly characterize clinically diagnosed posterior microphthalmos.

DESIGN

Prospective case series.

METHODS

Twenty-five affected patients from 13 families diagnosed by ophthalmologists experienced with the condition at the King Khaled Eye Specialist Hospital were studied. All participants underwent axial length measurement, keratometry, corneal pachymetry, and candidate gene analysis (MFRP, PRSS56). Main outcome measures were the results of ocular biometry and gene analysis.

RESULTS

All patients (2-47 years of age) had high hyperopia, normal-appearing anterior segments, posterior chamber foreshortening, and characteristic papillomacular folds/wrinkles. For the right eye, mean cycloplegic refraction was +15.09 diopters (D) (range 9.88-18.75). Axial length (mean 16.25 mm [range 14.88-19.88]) had strong inverse correlation (Pearson coefficient -0.88, P < .0001) with corneal power (mean 48.89 D [range 41.91-52.25]) and a positive correlation with corneal diameter (Pearson 0.64, P = .001). Corneal thickness and anterior chamber dimensions were within normal ranges. Left eye data were similar. Nineteen Saudi patients (8/13 families) harbored 4 different homozygous PRSS56 mutations, 1 Indian and 1 Saudi patient harbored 2 different homozygous MFRP mutations, and 4 Saudi patients (3/13 families) had no detectable mutation in either gene. Patients with MFRP mutations were not clinically different from patients with PRSS56 mutations or no identified mutation. Truncating PRSS56 mutations were associated with shorter axial lengths (mean 15.72 mm) than missense PRSS56 mutations (mean 16.37 mm) or no identified mutation (mean 17.57 mm).

CONCLUSIONS

These data define posterior microphthalmos biometrically and reveal that corneal steepening proportional to the degree of axial foreshortening is part of the phenotype. Corneal diameter decreases with decreasing axial length, suggesting posterior microphthalmos and nanophthalmos represent a spectrum of high hyperopia rather than distinct phenotypes. In the Saudi population PRSS56 mutations are the major cause, and in our cohort truncating mutations were associated with a more severe phenotype.

Spectral domain optical coherence tomography findings in retinal folds associated with posterior microphthalmos

Posterior microphthalmos is a rare congenital malformation characterized by normal anterior segment dimensions with an abnormally small posterior segment resulting in high hyperopia. Reduced visual acuity in these cases is sometimes caused by the presence of papillomacular retinal folds. We report two cases of posterior microphthalmos in which the papillomacular folds could be visualized on spectral domain optical coherence tomography with sufficient detail to illustrate that only the layers of neural retina within the external limiting membrane were involved.

Spectral domain optical coherence tomography finding in posterior microphthalmos

An eight-year-old boy presented with decreased vision in both eyes. At presentation, the visual acuity was 6/60 in both eyes with high plus spheres. Anterior segment examination was normal. Fundus examination and spectral domain optical coherence tomography were consistent with posterior microphthalmos and showed an elevated foveal contour and fold in the outer plexiform layer. External limiting membrane, photoreceptor and retinal pigment epithelium were not involved in the fold. To the best of our knowledge this is the first such case report with optical coherence tomography imaging of the retinal layer involved in a case of posterior microphthalmos.

Optical coherence tomography findings of retinal folds in nanophthalmos

Aim. To report the optical coherence tomography (OCT) findings in three members of the same family with nanophthalmos associated with elevated papillomacular retinal fold. Methods. Complete ophthalmic examination as well as ultrasonography and OCT was performed in all patients. Results. Axial lengths ranged from 16.75 mm to 17.48 mm and refractive errors ranged from +17.50 D to +20.50 D. Main fundus findings were the hyperopic crowded, cupless optic disc, and retinal fold through papillomacular region. Macular OCT scans revealed retinal fold with normal retinal pigment epithelium and choriocapillaris. Interpretation. It is presumed that the retinal folds in nanophthalmos result from a redundancy of the retinal layer caused by retarded growth of the scleral, choroidal, and retinal pigment epithelial layers. The anatomic information provided by the current study is consistent with this thesis.

Autosomal-recessive posterior microphthalmos is caused by mutations in PRSS56, a gene encoding a trypsin-like serine protease

Posterior microphthalmos (MCOP) is a rare isolated developmental anomaly of the eye characterized by extreme hyperopia due to short axial length. The population of the Faroe Islands shows a high prevalence of an autosomal-recessive form (arMCOP) of the disease. Based on published linkage data, we refined the position of the disease locus (MCOP6) in an interval of 250 kb in chromosome 2q37.1 in two large Faroese families. We detected three different mutations in PRSS56. Patients of the Faroese families were either homozygous for c.926G>C (p.Trp309Ser) or compound heterozygous for c.926G>C and c.526C>G (p.Arg176Gly), whereas a homozygous 1 bp duplication (c.1066dupC) was identified in five patients with arMCOP from a consanguineous Tunisian family. In one patient with MCOP from the Faroe Islands and in another one from Turkey, no PRSS56 mutation was detected, suggesting nonallelic heterogeneity of the trait. Using RT-PCR, PRSS56 transcripts were detected in samples derived from the human adult retina, cornea, sclera, and optic nerve. The expression of the mouse ortholog could be first detected in the eye at E17 and was maintained into adulthood. The predicted PRSS56 protein is a 603 amino acid long secreted trypsin-like serine peptidase. The c.1066dupC is likely to result in a functional null allele, whereas the two point mutations predict the replacement of evolutionary conserved and functionally important residues. Molecular modeling of the p.Trp309Ser mutant suggests that both the affinity and reactivity of the enzyme toward in vivo protein substrates are likely to be substantially reduced.

Optical coherence tomography findings for nanophthalmic eyes

PURPOSE

To describe the optical coherence tomography (OCT) findings for nanophthalmic eyes.

METHODS

: In this retrospective, single-center, observational case series, 15 patients (28 eyes) with axial lengths of <or=20.5 mm were included. Ultrasonography (A- and B-scans), keratometry, and OCT were performed. The main outcome measures were average foveal thickness, foveal center point thickness, total macular volume, and a new quantitative measure of foveal depression, relative foveal depression (RFD). Reference values for RFD were obtained by examining 57 healthy eyes with axial lengths of 21.5 mm to 27 mm.

RESULTS

The foveae of nanophthalmic eyes had diminished foveal depression due to thickened outer retinal layers. One patient with papillomacular folds was identified as having posterior microphthalmos. There was a good correlation between axial length on one hand and foveal thickness, foveal center point thickness, macula volume, and RFD on the other hand (r = -0.58, -0.61, -0.56, and -0.70 with P = 0.003, 0.001, 0.004, and 0.000, respectively). The average RFD for eyes with normal axial lengths was 0.43.

CONCLUSIONS

OCT findings for nanophthalmic eyes with foveal underdevelopment are different from posterior microphthalmos and foveal hypoplasia seen in other disorders. The new measure RFD is a useful tool in ocular tomography.

Nanophthalmos in a Melanesian population

PURPOSE

To characterize the ophthalmic features and causes of visual loss in a cohort of Melanesians living in New Caledonia with nanophthalmos.

METHODS

In this observational study, axial length, visual acuity (VA), cycloplegic autorefraction were assessed and dilated fundus examination was performed. Visual impairment was defined as VA<6/12 in the better eye, hypermetropia as >+1.0 dioptre (D), astigmatism as >or=1.0 D and anisometropia as >or=1.0 D difference between both eyes. Unilateral amblyopia was defined as at least a two-line difference in VA between both eyes and bilateral amblyopia as VA<6/12 in both eyes which was not adequately explained by refractive error and macular folds.

RESULTS

Seventeen community-dwelling participants (aged 1.1-45.3 years) with short axial length (range from 16.1 to 21.6 mm) were identified. Of the 17 subjects, 14 were found to have crowded optic discs, three with papillomacular folds, three with a papillomacular band and three with macular radial folds. Further, all subjects demonstrated bilateral hypermetropia (range from +1.3 D to +15.1 D). A high proportion of subjects had astigmatism (12) and anisometropia (nine) in at least one eye. Visual impairment was found in nine subjects: five bilateral and four unilateral. Causes of visual impairment included amblyopia (seven), ametropia (seven) and macular folds (two). Amblyopia was attributed to several factors, including hypermetropia, anisometropia, astigmatism and esotropia.

CONCLUSIONS

In this sample of Melanesians with nanophthalmos, a spectrum of ophthalmic features that was consistent with intraocular crowding was found. Over half of the subjects were visually impaired, mostly due to amblyopia and ametropia. Further characterization of the underlying genetic cause of nanophthalmos in this cohort will be the focus of future studies.

Pervasive ocular anomalies in posterior microphthalmos

BACKGROUND

Posterior microphthalmos is a relatively rare condition that has been reported to coexist with several other ophthalmic conditions. However, to the best of the authors' knowledge, there are no previous reports that have found posterior microphthalmos and refractive, binocular, retinal, and neurologic considerations, along with a possible hereditary component. The following report documents the coexistence of posterior microphthalmos with severe hyperopia, esotropia, macular folds, and optic nerve hypoplasia in a pair of siblings.

CASE REPORT

A 9-year-old Hispanic girl presented for a comprehensive eye examination. Best-corrected visual acuity (VA) was reduced in both eyes with poorer VA in the right eye. Binocular testing found a small angle constant right esotropia (ET). On dilated fundus examination, a peculiar, elevated, dolphin-shaped folding of the macula was identified, the right eye greater than the left eye, that extended toward an anomalous optic nerve head in both eyes (OU), presumed to be a disc hypoplasia. The patient's brother, who also exhibited severe hyperopia and ET, presented with a similar acuity reduction, a nearly identical folded macular appearance, the right eye more so than the left eye, and a probable optic nerve hypoplasia. Pachymetry, ultrasonography, and ocular coherence tomography imaging of both siblings found thickened corneas in the presence of posterior microphthalmos OU and macular folds affecting only the retina, leaving the choroid and sclera unaffected.

CONCLUSIONS

Posterior microphthalmos may exist in the presence of ocular anomalies along with refractive, binocular, retinal, neurologic, and genetic considerations. In this case, optical coherence tomography provided information on the internal morphology of the macular folds, which helped direct the differential diagnosis. The similar presentation among siblings supports a hereditary component that warrants further investigation.