Adult onsetfoveo-macular vitelliform dystrophyThe adult variant of Best disease,i.e adult onset foveo-macular vitelliform dystrophy presents in the sixthdecade. Similar to Best disease, subretinal accumulation of lipofuschincontributes to progressive foveal thinning, RPE atrophy and finally MHformation.(30–32) Studies on surgical results in theseeyes are limited, with one study reporting hole closure with prolonged siliconeoil tamponade after recurrence with standard vitrectomy procedure.(31) The functional outcome was excellentin this case with final BCVA of 20/40.
This may be due to shorter duration ofdisease as compared to Best disease. Gyrate atrophySharma et al reported a case ofbilateral macular holes in a 28 year old patient with gyrate atrophy of thechoroid and retina.(33) It is an autosomal recessive diseasecaused by mutation in ornithine aminotransferase gene. It is associated withaxial myopia, cataract and chorioretinal atrophic patches with scallopedmargins. The proposed mechanism was acceleration of PVD due to axial myopia andresulting anterior-posterior traction may have caused abrupt dehiscence of thefovea.
(33) Similar to RP where peripheral fieldis already constricted, foveal involvement jeopardises the remaining field.X- linkedretinoschisisX-linked retinoschisis is animportant cause of macular degeneration in young males with characteristicfoveal schisis in stellate or cart-wheel pattern and peripheral retinoschisis.(34–37) Muller cell cone plays a key roleand is the site of foveal splitting and cyst formation.(34) The defective protein retinoschisinaccumulates within the Muller cells in the form of cystic spaces which coalesceto form large cysts.
The inner layer degenerates with or without additionaltangential traction leading to MH formation. Vitreoretinal traction has beenconsidered to play an additional role by a single author where RD coexisted andVMT was documented clearly on OCT.(36) MH occurs in these eyes withinsecond to third decade.
Schisis, bulbous ends and cuff of fluid are thepredominant features on OCT. Visual acuity is usually better than 20/200 unlessRD is present. Vision loss worsens in adulthood when underlying RPE and outerretina undergoes degeneration. Study on surgical outcomes are lacking for XLRrelated MH.Bietti crystallinecorneo-retinal dystrophyBietti crystalline dystrophy (BCD) isan autosomal recessive retinal and choroidal dystrophy characterized byyellow-white crystalline deposits in the retina, pigment clumping as in RP, RPEand choriocapillaris degeneration, and choroidal sclerosis, with or withoutcorneal crystals.
CME and MH have been reported infrequently in these eyes withsimilar mechanism as in RP.(38–40) Nourinia et al successfully managedsuch a case in a 42 year adult with routine MH surgery with improvement in BCVAfrom FCCF to 20/50.