mydriatics and anaesthetic

Comprehensive Eye Examinations

• Retinal examination is crucial for diagnosing conditions like diabetic retinopathy, macular degeneration, and retinal detachment
• Fundus examination is used to examine the back of the eye more thoroughly
• Glaucoma assessment is performed to evaluate the optic nerve head and periphery of the retina

Therapeutic Indications

• Uveitis/iritis: to relieve pain and prevent posterior synechiae
• Amblyopia treatment: penalization therapy is used to encourage use of the amblyopic eye
• Corneal injuries and infections: to reduce ciliary muscle spasm and associated pain

Pre-Surgical Indications

• Cataract surgery: to provide a better view of the lens and facilitate surgical procedures
• Retinal surgery: to enhance visualization of the retina and facilitate surgical procedures

Conditions Requiring Detailed Examination

• Diabetic retinopathy: to monitor progression and severity of retinal changes
• Hypertensive retinopathy: to assess retinal vascular changes
• Age-related macular degeneration: to evaluate the macula for drusen, atrophy, or neovascular changes

Contraindications and Cautions

• Narrow-angle glaucoma: mydriasis can precipitate angle-closure glaucoma
• Allergic reactions: patients with known allergies should avoid mydriatic agents
• Systemic conditions: certain heart diseases may be exacerbated by systemic absorption of mydriatic agents

Common Agents Used for Inducing Mydriasis

• Tropicamide: commonly used for routine eye examinations due to its short duration of action
• Phenylephrine: often used in combination with other agents for its potent mydriatic effect
• Cyclopentolate: used when both cycloplegia and mydriasis are desired

Side Effects of Mydriasis

• Increased light sensitivity (photophobia)
• Blurred vision
• Stinging or burning sensation
• Allergic reactions
• Dry eyes
• Angle-closure glaucoma

Systemic Side Effects of Mydriatic Agents

• Increased heart rate (tachycardia)
• Increased blood pressure (hypertension)
• Dry mouth and skin
• Urinary retention
• Central nervous system effects

Specific Considerations for Different Agents

• Tropicamide: generally well-tolerated with mild and short-lived side effects
• Phenylephrine: can lead to systemic vasoconstriction and increased blood pressure
• Cyclopentolate: can cause significant cycloplegia and CNS effects

Local Anesthesia in Optometry

• Onometry: measuring intraocular pressure (IOP) using methods like Goldmann applanation tonometry
• Gonioscopy: examining the anterior chamber angle to assess for glaucoma
• Ultrasound pachymetry: measuring corneal thickness
• Contact lens fitting: for fitting rigid gas-permeable contact lenses

Therapeutic Procedures

• Foreign body removal: removing foreign objects from the cornea or conjunctiva
• Corneal scraping: taking corneal scrapings for microbiological examination
• Punctal plugs: insertion of punctal plugs to treat dry eye syndrome
• Minor surgical procedures: chalazion removal and laser procedures

Local Anesthetics Used in Optometry

• Proparacaine: often used due to its rapid onset and relatively short duration of action
• Tetracaine: provides a longer duration of anesthesia compared to proparacaine

Administration and Precautions

• Topical application: local anesthetics in optometry are usually applied as eye drops
• Single-use: use single-dose units to prevent contamination and infection
• Allergy check: ensure patients are not allergic to the anesthetic agent
• Avoid overuse: excessive use of topical anesthetics can cause corneal toxicity and delayed healing
• Contraindications: patients with known hypersensitivity to the anesthetic agent

Side Effects of Local Anesthetics

• Transient stinging or burning sensation upon instillation
• Corneal epithelial damage with prolonged or repeated use
• Rarely, allergic reactions manifesting as redness, swelling, or itching