Next-generation sequencing-based genetic testing and phenotype correlation in retinitis pigmentosa patients from India

Purpose: Inherited retinal dystrophies (IRD) are a heterogeneous group of retinal diseases leading to progressive loss of photoreceptors through apoptosis. Retinitis pigmentosa (RP) is considered the most common form of IRD. Panel?based testing in RP has proven effective in identifying the causative genetic mutations in 70% and 80% of the patients. This is a retrospective, observational, single?center study of 107 RP patients who had undergone next?generation sequencing?based targeted gene panel testing for IRD genes. These patients were inspected for common phenotypic features to arrive at meaningful genotype–phenotype correlation. Methods: Patients underwent complete ophthalmic examination, and blood was collected from the proband for DNA extraction after documenting the pedigree. Targeted Next Generation Sequencing (NGS) was done by panel?based testing for IRD genes followed by co?segregation analysis wherever applicable. Results: Of the 107 patients, 72 patients had pathogenic mutations. The mean age of onset of symptoms was 14 ± 12 years (range: 5–55). Mean (Best Corrected Visual Acuity) BCVA was 6/48 (0.9 logMAR) (range 0.0–3.0). At presentation, over one?third of eyes had BCVA worse than 6/60 (<1 logMAR). Phenotype analysis with the gene defects showed overlapping features, such as peripheral well?defined chorioretinal atrophic patches in patients with CERKL, PROM1, and RPE65 gene mutations and large macular lesions in patients with RDH12 and CRX gene mutations, respectively. Nummular or clump?like pigmentation was noted in CRB1, TTC8, PDE6A, and PDE6B. Conclusion: NGS?based genetic testing can help clinicians to diagnose RP more accurately, and phenotypic correlations can also help in better patient counselling with respect to prognosis and guidance regarding ongoing newer gene?based therapies.

Outcomes of macular buckling with a T-shaped buckle for myopic tractional maculopathies associated with posterior staphyloma: An Indian experience

Purpose: To report the anatomic and visual outcomes following macular buckling in patients affected by pathological myopia?associated foveoschisis (FS) and macular detachment with or without macular hole (MH). Methods: A retrospective interventional consecutive case series wherein 25 highly myopic eyes (mean axial length 28.46 mm; range, 25–33.8 mm) of 24 patients (16 females and 8 males; mean age 54.1 years; range, 35–74 years) presenting with macular detachment associated with a posterior staphyloma (PS), who underwent macular buckling, were evaluated. Patients with absence or reduction in subretinal fluid by more than 90% during the final follow?up along with inversion of contour of staphyloma were considered to have a successful anatomical outcome and those with improvement or maintenance in visual acuity were considered to have a successful functional outcome. The mean duration of follow?up was 11.2 months. Results: At the time of initial presentation, the mean age of the 24 patients was 54.1 ± 10.28 years. Macular detachment along with FS was present in all cases, whereas full?thickness macular hole?related retinal detachment was present in nine cases. Swept?source optical coherence tomography parameters showed reduction of FS with foveal reattachment in all eyes except one at last visit. Mean axial length decreased from 28.5 mm preoperatively (range 26–33.8 mm) to 26.2 mm (range 24–29.3 mm). The mean best?corrected visual acuity changed from 1.16 log MAR to 1.096 Log MAR (P = 0.165). Visual acuity improved in 10 eyes (40%), remained stable in 11 eyes (44%) and decreased in 4 eyes (16%). Conclusion: Macular buckling is a good surgical technique with encouraging anatomic and visual outcomes in patients with myopic macular detachment associated with PS. Highly selective cases of myopic traction maculopathy can have a viable option of macular buckle surgery in stabilizing the retinal tractional changes, and thereby, vision loss.

Choroidal neovascularization associated with coloboma of the choroid: A series of three cases.

Choroidal neovascularization (CNV) is a rare complication associated with coloboma of the choroid. We describe three cases of coloboma choroid where there was loss of vision due to CNV development at the edge of the coloboma. One was managed by photodynamic therapy alone and two were managed by a combination of reduced fluence PDT and intravitreal bevacizumab. Significantly we noted that one treatment session was sufficient to achieve regression of the CNV and improvement in visual acuity.

Serous macular detachment associated with dysplastic disc.

The article describes a case of abnormal looking optic disc (dysplastic) associated with serous macular detachment similar to what is described in cases of optic pit. However clinically as well as on fluorescein angiography, no optic pit or coloboma could be identified. Gas injection, prone positioning and laser along the temporal border of the disc could correct the macular detachment.