Retinal detachment in albinism

Successful treatment of retinopathy of prematurity in oculocutaneous albinism with OCA2 variants: a case report and review of literature

BACKGROUND

Oculocutaneous albinism (OCA) is a group of autosomal recessive hereditary disorders that affect melanin biosynthesis, resulting in abnormalities in hair, skin, and eyes. Retinopathy of prematurity (ROP) is a proliferative retinopathy mainly observed in premature infants with low birth weight and early gestational age, but it can also affect full-term infants or children with normal weight, particularly in developing countries. The coexistence of ROP and OCA is rare. There is limited documentation regarding treatment approaches, with few studies reporting positive outcomes with laser treatment due to the absence of melanin pigment. This study discusses the treatment challenges in a female infant diagnosed with ROP and OCA, and underscores the importance of genetic analysis in guiding therapeutic decisions for this rare comorbid condition.

CASE PRESENTATION

The study presents a case of ROP occurring concurrently with OCA. Genetic testing revealed two variants, c.727C > T (p.R243C) and c.1832 T > C (p.L611P), in the OCA2 gene, inherited from the patient's mother and father, respectively. The identified mutations were consistent with a diagnosis of OCA2, classified as a subtype of OCA. The patient initially received intravitreal anti-vascular endothelial growth factor (anti-VEGF) injection, followed by laser photocoagulation therapy for a recurrent event. A favorable outcome was observed during the 2-month follow-up period.

CONCLUSIONS

The co-occurrence of ROP and OCA is a rare phenomenon, and this is the first recorded case in the Chinese population. The current case supports the use of laser as the primary treatment modality for ROP in OCA2 patients with partial pigmentation impairment. Furthermore, genetic analysis can aid in predicting the effectiveness of laser photocoagulation in this patient population.

Sodium fluorescein dye as an adjunct in vitrectomy for rhegmatogenous retinal detachment in oculocutaneous albinism

A 48-year-old male with oculocutaneous albinism (OCA) presented with bilateral diminution of vision. Ocular examination revealed bilateral central corneal thinning, scarring with ectasia, depigmented irides, transillumination defects, and pseudophakia. Examination of the right eye also revealed a hyperoleon, emulsified silicon oil in the vitreous cavity, and an attached retina, while the left eye had a total rhegmatogenous retinal detachment (RRD). This case describes a unique set of challenges (the presence of an ectatic scarred cornea and a hypopigmented fundus) and sodium fluorescein dye as an adjunct in the surgical management of a complex RRD. A review of literature highlighting the association of keratoconus and RRD in OCA is also presented in this report.

INADVERTENT GLOBE PENETRATION AND SUBRETINAL INJECTION OF BOTULINUM TOXIN IN A PATIENT WITH OCULOCUTANEOUS ALBINISM

PURPOSE

To present a case of localized retinal detachment and mild vitreous hemorrhage in a patient with oculocutaneous albinism after accidental intraocular injection of botulinum toxin A.

METHODS

Botulinum toxin A injection was administered to a 5-year-old patient with oculocutaneous albinism with esotropia and resulted in an ocular penetration. Dilated fundus examination indicated a nasal retinal tear causing a mild vitreous hemorrhage and a localized retinal detachment.

RESULTS

No treatment was required for the retinal detachment, and we observed the patient at regular intervals. On Day 1, the detachment resolved spontaneously without sequelae. On follow-up, scarring at the lesion site was detected at one month after the incidence, and the patient's vision was stable.

CONCLUSION

In this instance, observation was sufficient for our patient with complete resolution of retinal detachment and no long-term complication. Botulinum toxin A did not seem toxic to intraocular tissues. However, intramuscular botulinum toxin A injection should be administered carefully. Oculocutaneous albinism did not seem to affect the final outcome in our case.

Management of complicated proliferative diabetic retinopathy in a patient with oculocutaneous albinism

Purpose

To describe the management and outcome of a patient with oculocutaneous albinism and complicated proliferative diabetic retinopathy, as well as to discuss treatment challenges and strategies in this patient population.

Observation

A 52-year-old patient with oculocutaneous albinism and diabetes presented with light perception vision in her right eye and 20/300 vision in her left eye. Examination showed a diabetic tractional retinal detachment in the right eye and high-risk proliferative diabetic retinopathy (PDR) in the left eye. In the right eye, the patient underwent pars plana vitrectomy, membrane delamination, endolaser therapy, and silicone oil tamponade, with follow-up evaluations showing a flat retina under silicone oil with regressed retinopathy in this eye. In her left eye, pan-retinal photocoagulation was attempted without success, with persistent PDR and absence of laser marks in this eye. Subsequently, the patient underwent six intravitreal anti-VEGF injections, after which she developed a tractional retinal detachment necessitating treatment cessation and a planned surgical intervention.

Conclusion and Importance

This case highlights the difficulty of using standard medical and surgical treatment strategies when caring for patients with oculocutaneous albinism and complicated proliferative diabetic retinopathy. If medical treatments fail in these patients, surgical approaches should be planned with extreme care due to the risks and challenges posed by hypopigmented fundi.

Method

Interventional case report.

Three-Dimensional Distribution Of Fundus Depolarization and Associating Factors Measured Using Polarization-Sensitive Optical Coherence Tomography

Purpose

To investigate the three-dimensional distribution and associating demographic factors of depolarization, using polarization-sensitive optical coherence tomography (PS-OCT), to evaluate melanin pigmentation in the retinal pigment epithelium (RPE) and choroid in healthy eyes.

Methods

In total, 39 unaffected healthy eyes of 39 subjects were examined using a PS-OCT clinical prototype. The degree of depolarization, expressed as the polarimetric entropy, was assessed in the RPE, the superficial and the total choroid layer, especially in the center, the inner, or the outer areas centered at the fovea. The values and their association with the demographic data were analyzed. Near-infrared fundus autofluorescence (NIRAF) was also used, in the same manner, for the comparison. Twenty-eight of 39 eyes were measured twice to evaluate intrasession repeatability.

Results

Both the polarimetric entropy in the RPE and the gray level in NIRAF, decreased from the center to the periphery (P < 0.001). The polarimetric entropy in the RPE was significantly associated with age in each area (P ≤ 0.001). In the RPE and the superficial choroid, the polarimetric entropy was negatively associated with axial length in each area (P ≤ 0.002). The intraclass correlation coefficient of the polarimetric entropy in the same session was excellent in each area of the RPE, superficial choroid, or total choroid layer (0.94–0.98).

Conclusions

The distribution of fundus melanin pigment-related depolarization was evaluated using PS-OCT. The depolarization was associated with the subjects’ demographic data, such as age or axial length.

Translational Relevance

The presented information in healthy eyes provides an essential basis for the investigation into a variety of chorioretinal pathologies.

Insights into the genetic basis of retinal detachment

Retinal detachment (RD) is a serious and common condition, but genetic studies to date have been hampered by the small size of the assembled cohorts. In the UK Biobank data set, where RD was ascertained by self-report or hospital records, genetic correlations between RD and high myopia or cataract operation were, respectively, 0.46 (SE = 0.08) and 0.44 (SE = 0.07). These correlations are consistent with known epidemiological associations. Through meta-analysis of genome-wide association studies using UK Biobank RD cases (N = 3 977) and two cohorts, each comprising ~1 000 clinically ascertained rhegmatogenous RD patients, we uncovered 11 genome-wide significant association signals. These are near or within ZC3H11B, BMP3, COL22A1, DLG5, PLCE1, EFEMP2, TYR, FAT3, TRIM29, COL2A1 and LOXL1. Replication in the 23andMe data set, where RD is self-reported by participants, firmly establishes six RD risk loci: FAT3, COL22A1, TYR, BMP3, ZC3H11B and PLCE1. Based on the genetic associations with eye traits described to date, the first two specifically impact risk of a RD, whereas the last four point to shared aetiologies with macular condition, myopia and glaucoma. Fine-mapping prioritized the lead common missense variant (TYR S192Y) as causal variant at the TYR locus and a small set of credible causal variants at the FAT3 locus. The larger study size presented here, enabled by resources linked to health records or self-report, provides novel insights into RD aetiology and underlying pathological pathways.