Lecture 15 for the final
How much + would you prescribe if there is 3.00D Latent hyperopia?
+0.75
On manifest refraction, you determine a prescription of +4.00D. If the patient's total hyperopia is +6.50D, what is the amount of facultative hyperopia?
+2.50
What % of glaucoma patients have a significant increase in IOP following dilation?
23%
The patient has adequate cycloplegia when there is
2D or less of residual accommodation
Total Hyperopia
= Manifest + Latent
Whether to prescribe depends on what 3 things?
Age, amount of hyperopia, and patient complaints
What are the top three strongest cycloplegic drops?
Atropine, scopolamine, Homatropine
What happens when the Vagus nerve is overstimulated?
Body's peripheral blood vessels dilate which lowers blood pressure and slows heart down - decrease heart pumping = no oxygen to brain = faint If the face is pale raise the tail
Name 3 indications for the use of cycloplegics
Esotropia - determine accom component (atropine drug of choice for under 4 years of age) Suspected latent hyperopia Suspected pseudo-myopia
Anesthetic drops Classified based on Esters or Amides
Esters (cocaine, procaine, proparacaine, tetracaine,benzocaine) Amides (lidocaine and bupivacaine)
Manifest hyperopia
Facultative + Absolute
Name 2 anticholinergic systemic reaction?
Fever, unable to sweat, facial flushing, tachycardia, dry mucous membranes, CNS toxicity, delirium
What refractive error does the majority of the population have?
Hyperopia
Tropicamide affects which iris muscle?
Inhibits cholinergic division = ciliary muscle paralysis Cycloplegia Inhibit action of the iris sphinctger - mydriasis
Treatment for an acute angle closure is
Laser peripheral iridotomy
96.4% of normal patient have an elevation in IOP in routine dilation of how much?
Less than 5 mmHg
Name 3 contraindications to cycloplegic
Narrow angles (history of narrow angle glaucoma), known allergy tod rug, iris fixed IOP (only very old patients), down syndrome (atropine)
Name 3 contraindications to Phenylephrine
Narrow angles, hypersensitivity, irisfixated IOL, Pts taking (MAO inhibitors, tricyclic antidepressants, reserpine, guanidine, and methyldopa)
other methods to determine residual accom
Pascal's and Duane's
After which medication use do older patients have a release of pigment granules?
Phenylephrine
Which routine dilating drop is a sympathomimetic med?
Phenylephrine
How long does Proparacaine anesthetize the eye?
Proparacaine lasts 10-15 minutes and onset is 10-20 seconds, Pts should be instructed not rub eyes - .5% is used
What are some adverse effects of anesthetics?
Punctate Keratitis, corneal edema, conjunctival hyperemia, stinging/lacrimation, delayed corneal healing Tear film instability - disrupt surface microvilli, Decreased reflex tearing, Reduced blink rate, epithelial toxicity, endothelial toxicity, and microbial contamination
How can you avoid systemic absorption of drops?
Punctual Occlude
What other effects does Phenylephrine have on the eye?
Pupil still reacts to bright light, conjunctival blanching
Acute Angle closure is usually secondary to
Pupillary block
Name 3 indications for dilation with mydriatics
Recent onset floaters and flashing lights, sudden decrease in VA, unexplained loss of VF, ocular pain or redness of unknown etiology, post trauma to eye or face, history of diabetes, presence of media opacities, history of retinal disease or detachments, or pupil defect or miosis
What is the cap color on the bottle of a mydriatic agent?
Red = mydriatic, White or clear = anesthesia, Green = miotic
With ant. seg. inflammation, cycloplegia stabilizes what?
Restore the blood aqueous barrier
Phenylephrine affects which iris muscle?
Stimulate the adrenergic division, sympathomimetics - increases pupil size by contracting iris dilator
Name 3 Cycloplegic side effects
Transient stinging, angle closure attack, transient IOP elevation, allergic reactions, visual hallucinations, increase BP/Tachycardia Systemic - flushing, fever, drowsiness, dry mouth and skin
Which routine dilating drop is a parasympatholytic med?
Tropicamide
What is the weakest cycloplegic drop?
Tropicamide (weakest), Cyclopentolate
If you patient's Dry RX = +1.50 and the Wet RX = +3.50, what should you prescribe?
Wet - Dry = latent Use latent table +3.50 - 1.50 = +2.00 Table says give them +0.50 of their latency Final add of +1.50 + 0.50 = +2.00
What method will we use to determine residual accommodation in the lab?
Yasuna's method - correction in phoropter, add +3.00D OU, occlude one eye, add +.025 step to blur, replace +3.00D OU again, reduce 0.25D to blur. Dioptric difference (absolute value) = residual accom
Cycloplegia
blurred vision at near due to paralysis of ciliary muscle
Eyestrain
describes any complaint involving a feeling of fatigue, discomfort or pain localized in or about the eyes or thought to be associated with the use of the eye - Cycloplegic Refraction
Mydriasis
dilated pupils (dilator contraction by adrenergic agonists or sphincter relaxation by muscarinic antagonists
Without additional information on amplitudes, you should
divide into cycloplegic and non-cycloplegic findings or Total = Facultative + Absolute
Manifest
is amount of hyperopia that can be measured by relaxation of accommodation with plus lenses
Latent
is amount of hyperopia that cannot be readily relaxed in routine refractive exam
Facultative
is the amount of hyperopia that can be overcome by accommodation
Absolute
is the amount of hyperopia that cannot be compensated for by accommodation
Anesthetic drops block
sodium channels
Manifest NBEO way
strongest plus lens to get max VA
Absolute NBEO way
weakest plus lens the get max VA