Retinitis is an inflammatory process in the retina of the eye caused by endogenous or exogenous mechanisms of development. Clinically, disease is manifested by a decrease in visual acuity, changes in the boundaries of the visual field, metamorphopsy, color perception disorder. Diagnosis includes ophthalmoscopy, visometry, perimetry, color testing, fluorescence angiography of the fundus, OCT, electrophysiological studies. In the treatment of this disease, local and systemic antibiotic therapy, antiviral therapy, corticosteroids, vasodilators and metabolic drugs are used.
H30 Chorioretinal inflammation
The retina is the most important and most complex structure of the eye, containing photoreceptors (rods and cones) and providing the function of central and peripheral vision. Thanks to the cones, high visual acuity and color perception are achieved, with the help of sticks – peripheral and twilight vision. Therefore, with retinitis, first of all, the visual function suffers. Due to the anatomical connection with the vascular membrane (choroid), inflammation of the retina rarely occurs in isolation, and more often manifests itself in the form of posterior uveitis – chorioretinitis.
In most cases, the development is caused by hematogenic entry into the retina of microorganisms and their toxins from extra-ocular foci of infection. Retinitis can occur against the background of concomitant pyelonephritis, pneumonia, endocarditis, erysipelas, tuberculosis, syphilis, meningitis, sepsis. The causative agents of metastatic (septic) retinitis are Staphylococcus, Streptococcus, Pneumococcus, Mycobacterium tuberculosis, pale treponema, etc. bacterial pathogens.
Less often in ophthalmology there are retinitis of viral etiology caused by pathogens of herpes simplex, herpes zoster, adenoviruses, influenza virus, measles, etc. In some cases, disease develops with toxoplasmosis, typhus, sarcoidosis, actinomycosis, brucellosis, leprosy. Endogenous retinitis can occur on the basis of diabetes mellitus, autoimmune pathology, leukemia.
Exogenous retinitis can be caused by mechanical damage to the eyes with retinal injuries, deep burns, perforation of corneal ulcers, exposure to ionizing radiation or direct sunlight. Along with this, there are retinitis of unclear etiology; in addition, their hereditary conditionality is not excluded.
The classification is based on the etiological principle, in connection with which endogenous and exogenous retinitis are distinguished. Endogenous lesions of the retina include:
- retinitis developed against the background of infectious diseases: tuberculosis, syphilitic, toxoplasma, brucellosis, leprosy, septic, etc.
- retinitis caused by diseases of the metabolism and blood system: diabetic, albuminuric, leukemic, etc.
- retinitis of unclear etiology: exudative, shingling, etc.
- hereditary retinitis: retinitis pigmentosa and its varieties. In modern ophthalmology, hereditary retinitis is attributed to retinal degeneration (retinopathy).
Exogenous forms of the disease are represented by solar, traumatic and other types.
By localization, there are widespread, disseminated retinitis and localized retinitis developing in the center of the retina, around the vessels or OND.
The resulting inflammation causes the destruction of retinal elements in the inflammatory focus area, lymphocytic infiltration of retinal and choroid layers. The organization of the focus of inflammation is accompanied by the formation of scar tissue. With retinitis, the breakdown of retinal nerve elements occurs, fatty degeneration of ganglion cells and Muller support fibers, destruction of rods and cones, necrotization of the pigment epithelium. The vascular reaction is characterized by the phenomena of vasculitis, a change in the caliber of vessels, their partial blockage and final obliteration. Often there are extensive hemorrhages in the retina itself and under it.
Inflammation of the retina proceeds painlessly, therefore, the main subjective manifestations of retinitis are different degrees of visual acuity reduction. To the greatest extent, central vision is impaired when the inflammatory focus is localized in the macular region; in this case, color perception also suffers. When the periphery of the retina is damaged, visual field defects occur with the loss of certain areas (“tunnel vision”), dark adaptation decreases.
Often, with retinitis, metamorphopsia occurs – distortion of visual perception, blurring of objects and photopsia – sensations of light flashes (sparks, lightning) in the eyes.
The resolution is accompanied by the formation of extensive chorioretinal scars and a persistent decrease in vision. Retinitis may cause hemorrhages in the retinal tissue and vitreous (hemophthalmos), exudative or traction retinal detachment, optic nerve atrophy. When the infection spreads to other eye tissues, uveitis, optic neuritis, endophthalmitis and panophthalmitis may develop, followed by eye loss.
Diagnostics and differential diagnostics of various forms are carried out on the basis of ophthalmological tests (visometry, achromatic and color determination of visual fields, computer perimetry, color testing), examination of eye structures (ophthalmoscopy, diaphanoscopy, fundus biomicroscopy), optical and radiological studies (OCT, fluorescent angiography). The etiology of retinitis is established on the basis of the patient’s epidamnesis.
The assessment of the fundus is of the greatest importance in the diagnosis of retinitis. The ophthalmoscopic picture of tuberculous retinitis is characterized by disseminated retinal lesion with the presence of numerous small or several large chorioretinal foci. With syphilitic retinitis, multiple foci of light and dark colors (“salt and pepper”), diffuse retinal edema and OND, pigmented areas of vascular atrophy are detected on the periphery of the fundus. Toxoplasmic form occurs with damage to other membranes of the eye (iridocyclitis and episcleritis); during ophthalmoscopy, a central loose focus of yellow-green color with phenomena of perifocal inflammation is determined. With solar retinitis, yellowish-white spots with a gray rim are first detected on the fundus, which then turn into clearly defined red foci.
When examining the visual fields, scotomas (peripheral, near-central, central), concentric narrowing of the visual fields are detected. With the help of contrast angiography of retinal vessels, vascular changes are detected: their narrowing or expansion, unevenness of caliber, formation of couplings, obliteration. Optical coherence tomography in retinitis helps to assess structural changes in retinal tissues. In order to more thoroughly assess the function of the retina, electrophysiological studies are performed – electroretinography, determination of the critical frequency of the fusion of flickers, etc.
To establish a bacterial or viral pathogen, a blood culture for sterility, PCR and ELISA study is carried out. If autoimmune etiology is suspected, specific immunological tests are performed.
In addition to the ophthalmologist, other narrow specialists are involved in the diagnosis and treatment of a specific etiology: a phthisiologist, a venereologist, an infectious disease specialist, a rheumatologist, an endocrinologist-diabetologist, etc.
Establishing the cause and causative agent greatly facilitates its treatment. Etiologically justified complex anti-inflammatory therapy is prescribed: antibiotics (local instillation, parenteral administration), corticosteroids (eye drops and ointments). With retinitis of a viral nature, antiviral drugs are used (subconjunctival and parabulbar injections of interferon inducers, oral administration of acyclovir, etc.). With tuberculosis, syphilitic, toxoplasma and other specific retinitis, drugs aimed at treating a specific infection are included in therapy.
In the complex therapy of retinitis, vasodilators and antispasmodics, drugs that improve metabolism in retinal tissues (vitamins of groups A, E, etc.) are used. electrophoresis procedures with a solution of calcium chloride are shown.
With hemophthalmos, vitrectomy is resorted to; with retinal detachment, a laser coagulation procedure is performed.
Prognosis and prevention
The outcome of retinitis in all cases is a pronounced deterioration of visual function to varying degrees. Complete restoration of vision, as a rule, does not occur.
Prevention of endogenous retinitis is reduced to early detection and adequate treatment of the underlying disease. It is necessary to avoid eye injuries, to prevent solar retinitis – use eye protection from light radiation.