INTRODUCTIONUsing artificial means to treat extreme vision impairment has come closer to reality during the past few decades. The goal of this research has been to create an implantable medical device that provides useful vision for those patients who are left with no alternatives. Analogous to the cochlear implants for some forms of hearing loss, these devices could restore useful vision by converting visual information into patterns of electrical stimulation that excite the remaining viable inner retinal neurons in patients with retinitis pigmentosa or age-related macular degeneration.

METHODSData for this review were selected through a comprehensive literature search.

RESULTSAdvances in microtechnology have facilitated the development of a variety of prostheses that can be implanted in the visual cortex, around the optic nerve, or in the eye. Some of these approaches have shown the promise of providing useful visual input to patients with visual impairments.

CONCLUSIONWhile the development of various retinal prostheses have shown promise in limited clinical trials, there are distinct advantages and disadvantages for each type of prosthesis. This review will focus primarily on the Epiretinal Intraocular Retinal Prosthesis, studied by our group, but will also briefly review other modalities: the subretinal prosthesis, cortical prosthesis, and optic nerve prosthesis.

Electric Stimulation Therapy ; Electrodes, Implanted ; Humans ; Macular Degeneration ; complications ; Prosthesis Implantation ; Retinitis Pigmentosa ; complications ; Vision Disorders ; etiology ; rehabilitation

Abnormalities, Multiple ; diagnosis ; Child ; Diabetes Mellitus, Type 2 ; complications ; Female ; Hearing Loss, Sensorineural ; complications ; Humans ; Obesity ; complications ; Prognosis ; Retinitis Pigmentosa ; complications ; Skin ; pathology ; Syndrome

A 45-year-old man with retinitis pigmentosa (RP), who had undergone uneventful extracapsular cataract extraction (ECCE) in his right eye eight years previously, and phacoemulsification in his left eye six years previously, had spontaneously dislocated intraocular lenses (IOL) within the capsular bag in both eyes one month apart. We removed the dislocated IOLs, and performed anterior vitrectomy and scleral fixation of the new IOLs. Mild contraction of the capsular bags and uneven distribution of the zonular remnants' clumps along the equator of the capsules were found by scanning electron microscopic (SEM) examination. In this study, we propose the correlation between RP and zonular weakness. To our knowledge, this is the first case report of bilateral spontaneous dislocation of IOLs within the capsular bag of an RP patient.
Adult ; Foreign-Body Migration/*etiology ; Humans ; Lens Capsule, Crystalline/*pathology ; Lens Implantation, Intraocular ; *Lenses, Intraocular ; Ligaments/ultrastructure ; Male ; Microscopy, Electron, Scanning ; Phacoemulsification ; Reoperation ; Retinitis Pigmentosa/*complications ; Vitrectomy

PURPOSE: To report a case of bilateral spontaneous anterior lens dislocation associated with retinitis pigmentosa (RP). METHODS: A 45-year-old male with RP presented with elevated intraocular pressure (IOP) in the right eye and was treated with laser iridotomy (LI). After LI, complete crystalline lens dislocation into the anterior chamber occurred. Surgical intervention, including anterior vitrectomy, intracapsular cataract extraction (ICCE), and IOL scleral fixation was performed. Two years later, the same episode occurred in his left eye and a similar treatment was done. RESULTS: Surgery was successful in both eyes. CONCLUSIONS: This is the first report of bilateral spontaneous anterior lens dislocation in a RP patient.
*Anterior Chamber ; Cataract/complications/diagnosis ; Cataract Extraction ; Electroretinography ; Follow-Up Studies ; Humans ; Iris/surgery ; Laser Therapy/adverse effects ; Lens Implantation, Intraocular/methods ; Lens Subluxation/diagnosis/*etiology/surgery ; Male ; Middle Aged ; Ocular Hypertension/complications/physiopathology/surgery ; Retinitis Pigmentosa/*complications/diagnosis/surgery ; Sclera/surgery ; Suture Techniques ; Visual Fields ; Vitrectomy