DIMS Lectures Ophthalmology / Eye PDF
Introduction to Clinical Ophthalmology
Ophthalmology is the branch of medicine that focuses on the diagnosis, treatment, and management of eye diseases and disorders.
Refractive Errors
Definition:
Refractive errors occur when light is not focused properly on the retina due to an abnormal shape of the eye or lens.
Types:
- Myopia (Nearsightedness): Distant objects appear blurry.
- Hyperopia (Farsightedness): Nearby objects appear blurry.
- Astigmatism: Irregular curvature of the cornea causes distorted vision.
- Presbyopia: Age-related decline in near vision due to lens stiffness.
Diagnosis:
- Visual Acuity Testing using Snellen chart.
- Retinoscopy to determine refractive error.
Management:
- Eyeglasses or contact lenses.
- Refractive Surgery (LASIK, PRK) for permanent correction.
Corneal Diseases
Definition:
Corneal diseases affect the transparent front part of the eye, leading to visual impairment, pain, and photophobia.
Common Conditions:
Keratitis: Corneal inflammation due to infections (bacterial, viral, fungal, or parasitic).
Corneal Ulcers: Open sores on the cornea, commonly due to contact lens misuse.
Keratoconus: Progressive corneal thinning leading to irregular astigmatism.
Diagnosis:
Slit-lamp examination to assess corneal opacity, ulceration, and inflammation.
Corneal topography for keratoconus.
Management:
Bacterial Keratitis: Topical fluoroquinolone antibiotics.
Fungal Keratitis: Topical and systemic antifungal agents.
Keratoconus: Rigid contact lenses or corneal transplant in severe cases.
Cataract
Definition:
A cataract is clouding of the eye's natural lens, leading to progressive vision loss.
Causes:
- Aging (Senile Cataract)
- Diabetes Mellitus
- Prolonged corticosteroid use
- Congenital Cataracts
Clinical Features:
- Blurred vision
- Glare and difficulty in bright lights
- Reduced contrast sensitivity
Diagnosis:
- Slit-lamp examination
- Visual Acuity Testing
Management:
- Cataract surgery with intraocular lens (IOL) implantation.
Glaucoma
Definition:
A group of optic neuropathies characterized by increased intraocular pressure (IOP) leading to optic nerve damage.
Types:
- Open-Angle Glaucoma: Chronic, gradual vision loss.
- Angle-Closure Glaucoma: Acute, painful, and rapid vision loss.
Clinical Features:
- Peripheral vision loss (tunnel vision)
- Halos around lights
- Pain and headache (in acute cases)
Diagnosis:
- Tonometry (measures IOP)
- Ophthalmoscopy (optic disc cupping)
- Visual Field Testing
Management:
- Medications (Timolol, Latanoprost)
- Laser Therapy (Trabeculoplasty)
- Surgical Options (Trabeculectomy)
Uveitis
Definition:
Inflammation of the uvea (iris, ciliary body, choroid).
Types:
Anterior Uveitis (Iritis): Most common, associated with autoimmune conditions (Ankylosing Spondylitis).
Intermediate Uveitis: Involves the vitreous humor.
Posterior Uveitis: Affects the retina and choroid.
Panuveitis: Inflammation of all uveal structures.
Clinical Features:
Eye redness and pain
Photophobia
Blurred vision
Floaters
Diagnosis:
Slit-lamp examination
Fundoscopy for posterior uveitis
Management:
Topical corticosteroids (Prednisolone eye drops) for anterior uveitis
Systemic immunosuppressants for severe cases
Diabetic Retinopathy
Definition:
Diabetic retinopathy is a complication of diabetes affecting retinal blood vessels.
Types:
- Non-Proliferative Diabetic Retinopathy (NPDR): Microaneurysms, hemorrhages, and exudates.
- Proliferative Diabetic Retinopathy (PDR): Neovascularization, vitreous hemorrhage, and retinal detachment.
Clinical Features:
- Blurred vision
- Floaters and dark spots
- Gradual vision loss
Diagnosis:
- Fundoscopy (Retinal Examination)
- Fluorescein Angiography
Management:
- Blood sugar control
- Laser photocoagulation
- Intravitreal Anti-VEGF injections (Bevacizumab)
Age-Related Macular Degeneration (AMD)
Definition:
A degenerative disease of the macula, causing central vision loss.
Types:
- Dry (Non-Exudative) AMD: Gradual vision loss due to drusen accumulation.
- Wet (Exudative) AMD: Rapid vision loss due to abnormal blood vessel growth.
Clinical Features:
- Blurred or distorted central vision
- Difficulty reading or recognizing faces
- Metamorphopsia (wavy vision)
Diagnosis:
- Amsler Grid Test
- Optical Coherence Tomography (OCT)
Management:
- Antioxidant supplements (AREDS formula)
- Intravitreal Anti-VEGF injections
Retinal Detachment
Definition:
Separation of the retina from the underlying tissue, leading to potential blindness.
Causes:
- Trauma
- High Myopia
- Vitreous Degeneration
Clinical Features:
- Sudden onset of floaters and flashes
- Shadow or curtain over vision
- Painless vision loss
Diagnosis:
- Ophthalmoscopy
- B-scan Ultrasound
Management:
- Scleral Buckling Surgery
- Vitrectomy
Conjunctivitis
Definition:
Inflammation of the conjunctiva, commonly due to infection, allergies, or irritation.
Types:
- Bacterial Conjunctivitis: Purulent discharge, crusting of eyelids.
- Viral Conjunctivitis: Watery discharge, associated with upper respiratory infection.
- Allergic Conjunctivitis: Itchy, red eyes with tearing.
Diagnosis:
- Clinical Examination
- Conjunctival Swab (if severe)
Management:
- Bacterial: Topical antibiotics (Moxifloxacin)
- Viral: Supportive care, artificial tears
- Allergic: Antihistamines, mast cell stabilizers
Neuro-Ophthalmology
Definition:
Neuro-ophthalmology deals with conditions that affect the visual pathway, cranial nerves, and ocular motility.
Common Disorders:
Optic Neuritis: Inflammation of the optic nerve, often associated with multiple sclerosis.
Papilledema: Swelling of the optic disc due to raised intracranial pressure.
Third Nerve Palsy: Causes ptosis, eye deviation "down and out".
Diagnosis:
MRI Brain to assess for demyelinating or compressive lesions.
Visual Field Testing.
Management:
Steroids for optic neuritis.
Treatment of underlying cause for papilledema (e.g., intracranial hypertension).
Case Example: A 60-Year-Old with Sudden Vision Loss
A 60-year-old male with long-standing diabetes presents with sudden painless vision loss in one eye. Fundoscopic examination reveals vitreous hemorrhage with neovascularization.
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Diagnosis: Proliferative Diabetic Retinopathy with Vitreous Hemorrhage
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