We describe the clinical profile of patients with coexisting retinal dystrophies and primary angle closure disease presenting to a tertiary eye care hospital in India. PACD association with retinal dystrophies is rare, prevalence of PACG in retinitis pigmentosa is reported to range from 1.03–2.13%.[5–8] Association of PACG with other rare retinal dystrophies like X-linked juvenile retinoschisis, best vitelliform macular dystrophy, autosomal recessive and autosomal dominant bestrophinopathies are also reported.[10–13] In the present study, the prevalence of PACD with RP was 0.19%, lesser than previous reports and PACD with retinoschisis was 0.15%.
Our study has the largest cohort (46 patients) including retinal dystrophies with co-existing PACD. As per our study, PACD with retinal dystrophies was noted more commonly in males (63%) than females (36.9%). PACG was noted in 33 eyes of males and 20 eyes of females in our study. Babeed et al had reported three males with PACG and RP in their series of five patients.[1, 4, 5] Pradhan et al had reported female more common than males in their five patients case series. The reason for the male preponderance might be because the retinal dystrophies are more common in males, and also possibility of the female patients with retinal dystrophies not accessing care. In our study the mean age at diagnosis of any retinal dystrophy was 29.6 ± 9.4 years, and mean age at diagnosis of PACD was 32.23 ± 7.92 years. This indicates presentation of retinal dystrophy at an earlier age than PACG. This association is logical as most of the retinal dystrophies present usually at first or second decade of life.
Gao et al have studied the etiologies and the clinical characteristics of angle-closure glaucoma (ACG) patients in younger group (≤40 years) including primary and several secondary angle closure glaucomas. Mean age of the patients in their study was 25.6± 13.0 years. PACG (32.6%), uveitis (20.3%), and anterior segment dysgenesis (ASD) (15.1%) were the most common etiologies for occurrence of ACG in their study. Few other common etiologies found in association for ACG included iridocorneal endothelial syndrome, neovascular glaucoma, nanophthalmos, retinitis pigmentosa, spherophakia, bestrophinopathy, persistent fetal vasculature, iridociliary cysts, congenital retinoschisis, Marfan’s syndrome, retinopathy of prematurity, familial exudative vitreoretinopathy, congenital retinal folds, Coat’s disease, and neurofibromatosis. In their study 3% of the patients with ACG had RP and 2% of the patients with ACG had bestrophinopathy. The mean age at diagnosis of PACG in their patients was 34.4 ± 5.1 years (range, 13–40 years) similar to our study. The mean age of patients with RP and bestrophinopathy was 29.7 ±7.0 (range 18–39 years) and 26.2 ±6.4 (18–34) years respectively similar to our study.
Another study by Chang et al had also described the occurrence of angle closure in young patients (≤40 years). Mean age of the patients at hospital presentation was 34.4 ± 9.4 years (range, 3-68 years). Most common etiologies found were plateau iris syndrome, iridociliary cysts, retinopathy of prematurity and uveitis. The mean age of RP patients with PACG was 42.2 years (range 3-94 years) in various other studies.[5, 8] All our patients had primary angle closure and had retinal dystrophies for which they were under follow up, hence it is possible that the primary angle closure was diagnosed at an earlier age. All our patients had occludable angles with phakic lens status. Studies before have postulated the occurrence of PACG in RP patients is secondary to the laxity of the zonules and anterior lens subluxation leading to angle closure, which is a possibility, however no obvious lens subluxation with phacodonesis was noted in any of our cases.[8, 9] LPI followed by medical treatment based on the need was the primary modality to treat the angle closure in our study. 10 eyes in our study were misdiagnosed as open angles elsewhere and found to have occludable angles at our tertiary center. This highlights the need of proper gonioscopy and classification of PACD for appropriate treatment. Hence, gonioscopy is advised yearly to pick up coexisting angle closure in cases of retinal dystrophies with shallow anterior chamber or whenever the IOP is elevated. It is important to identify coexisting angle closure/glaucoma which is a potentially blinding disease. As in our study, although these subjects had retinal pathology and were advised follow up, many missed regular follow up and presented late. At the time of diagnosis of glaucoma, 18 eyes (19.5%) had poor vision (perception of light or no perception of light) due to advanced glaucoma. Hence it is important to educate the retinal specialists to counsel the patients for regular follow up and also evaluate for angle closure from second decade onwards.
RP was the most common dystrophy associated with PACG similar to previous studies. Other less common dystrophies were retinoschisis, best’s dystrophy and bestrophinopathies. Angle abnormalities, pigment accumulation in angles, lens thickness variabilities and vitreous disturbances have been postulated to be the pathophysiology behind occurrence of PACG in retinal dystrophies.[3, 5, 8, 12] Synechial angle closure with pigmentation was seen in 9 eyes with RP in our study, typical retinitis pigmentosa pigmentation (mid periphery and beyond bony spicule pigmentation) was seen in 74 eyes and 8 eyes with RP had some form of vitreous abnormalities (vitreous opacities/floaters, vitreoschisis and degenerative changes).
Glaucoma was managed medically in majority of the eyes and a minority of the eyes (11.9%) required surgical management for glaucoma with trabeculectomy. Post trabeculectomy one patient had shallow anterior chamber depth with aqueous misdirection and malignant glaucoma.
Strengths of our study are, largest sample size so far assessing the clinical characteristics of comorbid retinal dystrophies and primary angle closure disease. Limitations are retrospective study. Lack of visual field data in all patients to quantify the amount of peripheral visual loss and progression which happens in both glaucoma as well as retinal dystrophy.
Conclusion: Our study is the largest study so far with comorbid retinal dystrophies and PACD to the best of our knowledge. Among all dystrophies, retinitis pigmentosa is the most common dystrophy associated with PACD. PACD in retinal dystrophies mostly affects 2nd to 3rd decade adults. Males were most commonly affected than females. Presentation of retinal dystrophy is earlier than PACD. Our study highlights the need to educate the retinal specialists to counsel the patients for regular follow up and also evaluate for angle closure from second decade onwards. PACG is the most common presentation with retinal dystrophies among PACD spectrums. LPI and trabeculectomy are useful in management of intraocular pressure for PACD in retinal dystrophies cases. Future prospective studies are required to identify the rate of visual loss and progression.