Thursday, January 31, 2008

Retinal hemorrhages

Subhyaloid and preretinal hemorrhages
  • located on retinal surface
  • subhyaloid hemorrhage is located b/w the posterior vitreous base and the internal limiting membrane (ILM)
  • preretinal hemorrhage is located posterior to the ILM and anterior to the NFL
  • "boat-shaped" with sharp demarcation line
  • obscure retinal features
  • tend to clear quickly without any sequelae
  • associated with pathology affecting the major retinal vessels or superficial beds
  • most common etiology: retinal neovascularization
  • other etiologies: PVD, retinal breaks, associated with the tearing of a mjor retinal vessel
  • less common etiologies: Terson's syndrome, retinal trauma, valsava retinopathy

Flame-shaped hemorrhages (NFL hemorrhages)

  • located within the NFL
  • flame shape is the result of the structure of the NFL
  • typically located in the posterior pole
  • tend to resolve within a 6 weeks
  • associated with retinal vasculature pathology affecting the superficial and peripapillary capillary beds
  • etiology: hypertensive retinopathy (AV nicking present), retinal vein occlusions, optic neuropathy (papilledema, NTG, anterior ischemic optic neuropathy)
  • Roth spot = flame-shaped hemorrhage that has a white or pale center; represent non-specific signs of blood dyscrasias (anemia/thrombocytopenia, anoxia, AV malformation, bacterial endocarditis, collagen vascular disease, diabetic retinopathy, HIV, HTN retinopathy, leukemia, multiple myeloma, trauma)

Dot-and-blot hemorrhages

  • located in the retina's inner nuclear and outer plexiform layers
  • configuration is due to intraretinal compression
  • take longer to resolve because they're deeper than flame-shaped hemorrhages
  • commonly associated with microvascular signs of edema
  • etiology: pathology affecting the prevenular capillaries -- diabetic retinopathy, idiopathic juxtafoveal retinal telangiectassis, vein occlusion and OIS
  • OIS: vascular insufficiency associated with carotid artery disease leads to ocular hypoperfusion --> not enough pressure to push blood from retinal arterioles to the venules --> increased capillary congestion results in a breakdown of the capilary walls with subsquent hemorrhage and edema --> venules attempt to compensate for the decreased blood flow by distending, giving them a dilated, but non-tortuous appearance

Subretina and subretinal pigment epithelium (RPE) hemorrhages:

  • located beneath the neurosensory retina and the RPE
  • sub-RPE hemorrhages are located b/w the RPE and Bruch's
  • exhibit a dark coloration with the retinal vessels clearly visible above
  • tend to have an amorphous shape, due to the absence of firm attachments b/w the neursensory retina and RPE, allowing the blood to spread
  • sub-RPE hemorrhages have well-defined borders attributed to the tight cell junctions among RPE
  • may be associated with neurosensory or RPE detachments in the posterior pole
  • tend to resolve slowly
  • may be associated with the functional and/or structural changes at the level of the photoreceptors (therefore, unfavorable prognosis)
  • most common etiology: CNV
  • other etiologies: choroidal tumors, trauma, retinal angiomatous proliferation
  • referal to a retinologist

Management

  • referral if needed
  • patients without systemic history need medical work-up (most common etiologies: HTN, DM; other: clotting disorders such as hemophilia or patients on warfarin)
  • fasting plasma glucose test (<100> 126 is indicative for diabetes)
  • HbA1c (normal <5%)
  • CBC with white cell differential (test for anemias, polycythemias, bleeding disorders, leukemias, infections)
  • prothrombin time (PT) and international normalized ratio (INR) -- evaluates clotting factors
  • OIS: work-up of above plus heart echo, carotid USG and/or Doppler color imaging to rule-out carotid or heart disease
  • in older patients (>60) -- ESR & C-reactive protein & temporal artery biopsy to confirm
  • in younger patients (18-40) -- at risk for blood dyscrasias, diabetes, HTN, hyperlipidemia -- obtain a serum lipid profile, consider antiphospholipid and anticardiolipin enzymes to determine whether they have antiphospholipid syndrome; ANA or double-stranded DNA testing to r/o Lupus; ANA & ESR screening test for autoimmune diseases and inflammatory conditions
  • other tests: HLA-B51, HLA-B27, HLA-B5, ELISA, Western-blot specific testing for HIV, Lyme disease, toxoplasmosis, tuberculosis
  • other tests: FTA-Abs and RpR to r/o syphilis
  • other tests: blood cultures to identify widespread infection (speticemia)

Retinal vasculature anatomy

Retina blood supply from 1) retinal vasculature 2) choroidal vasculature
  • Carotid artery --> ophthalmic artery branch --> branches into the CRA (blood supply of the inner retina) --> branches in NFL to all quadrants except the foveal avascular zone
  • choroidal vasculature supplies nutrients and oxygen to the macula

Dry Eye -- Ocular Surface Disease Index

http://www.agape1.com/Questionnaires/Ocular%20Surface%20Disease.pdf


http://www.restasisprofessional.com/documents/OSDI_PAD.pdf

Punctal plugs codes

from: http://www.ocusoft.com/OcclusionTherapyRateCharts/CaiforniaRestofState.pdf

Diagnostic Codes used to characterize Lacrimal System Dysfunction:

  • Tear Film Insufficiency 375.15
  • Keratoconjuctivitis Sicca 370.33
    Redness or Discharge 379.93
  • Pain in or around eye 379.91

1st VISIT (LO1) - Lacrimal EfficiencyTesttm with dissolvable Collagen / CollaSyn™ test plugs in upper and lower puncta

  • Occlude left upper punctum with test plug 68761-E1
  • Occlude left lower punctum with test plug 68761-E2
  • Occlude right upper punctum with test plug 68761-E3
  • Occlude right lower punctum with test plug 68761-E4
  • 10 Day Post-Operative Period


2nd VISIT (LO2) - Non-Dissolvable or 6 Month Dissolvable VisiPlug™ Lacrimal Plugs in upper puncta, re-test lower puncta

  • Occlude left upper punctum 68761-E1
  • Occlude right upper punctum 68761-E3
  • Occlude left lower punctum with test plug 68761-E2
  • Occlude right lower punctum with test plug 68761-E4
  • 10 Day Post-Operative Period

3rd VISIT (LO3) - 6 Month Dissolvable VisiPlug™ Lacrimal Plugs® in lower puncta

  • Occlude left lower punctum 68761-E2 3
  • Occlude right lower punctum 68761-E4 3

RELATED CPT CODES

  • Probing of canaliculi, with / without irrigation,Plug Repositioning or Removal (L04, L05) 68840
  • Dilation of punctum, with / without irrigation, Plug Removal (LO5) 68801
  • Probing of nasolacrimal duct, with / without irrigation, Plug Removal (LO5) 68810

Tuesday, January 29, 2008

Combigan

brimonidine tartrate/timolol maleate 0.2%/0.5% (Allergan)

  • dual mechanism of action to lower IOP by reducing aqueous-humor production and enhancing aqueous-humor drainage/outflow
  • BID dosing
  • mean decrease from baseline IOP 4.4-7.6mm HG with Combigan (vs. 2.7-5.5 with brimonidine tartrate, vs. 3.9-6.3 with timolol)
  • maintained mean IOP throughout day better than individual gtts
  • mean daytime IOP was consistently <18>
  • systemic absorption helps to control for crossover effects of the drugs and controls for asymmetric fluctuations of IOP b/w right and left eyes
  • mean daytime decrease from baseline IOP was >20% in 42% of Combigan patients, 13% brimonidine, 27% timolol
  • lower incidence of conjunctival follicles compared to brimonidine (but higher than timolol group)
  • rate of discontinuation for adverse effects was 14% with Combigan (vs. 30.6 with brimonidine vs. 5.1% with timolol)
  • rate of allergic conjunctivitis was 5.2% with Combigan (vs. 9.4% brimonidine vs. 0.3% timolol)
  • contraindications: patients with bronchial asthma, sinus bradycardia, severe COPD, overt cardiac failure, cardiogenic shock, atrioventricular block

Monday, January 28, 2008

DLK after LASIK

  • inflammatory cells (eosinophils, neutrophils, lymphocytes) that migrated underneath the LASIK flap
  • leads to collagenolytic activity that weakens the corneal structure and leads to stromal melting and ectasia
  • 0.2%-5.3% incidence
  • occurs in both mechanical microkeratome and IntraLase procedures
  • usually due to bacterial endotoxins released from sterilizer reservoirs
  • can occur as soon as 24 hours after surgery or as a late-onset problem, occuring many months after surgery
  • increased risk: epithelial defects after surgery or patients who have atopic disease

Signs/symptoms:

  • symptoms may mimic dry eye
  • grainy appearance b/w the flap and underlying stromal bed
  • only mildly hyperemic conjunctiva
  • no ciliary flush like infectious keratitis
  • as severity increases, may cause decrease in VA, irregular astigmatism, ectasia, hyperopia

Treatment:

  • Pred Forte q1-2hour, follow-up every day until improves
  • topical fluoroquinolone tid prophylaxis if needed
  • cyclopentolate for pain
  • severe cases need referral back to surgeon to lift flap and irrigate the area with sterile balanced salt solution to remove inflammatory cells
  • severe cases oral prednisolone 40-80mg per day for at least one week

Corneal transplant examinations

Signs/symptoms of graft rejection
  • redness
  • irritation,
  • light sensitivity
  • FBS
  • blurred vision
  • general inflammatory response (vascular dilation and transudation)
  • cellular infiltration -- sub-epithelial infiltrates ~0.5 mm scattered throughout the donor tissue only (respond to topical steroids)
  • tissue edema
  • stromal rejection -- neovascularization and stromal infiltrates
  • endothelial rejection -- KPs scattered across the endothelium or in a linear form advancing in from the peripheral cornea; causes edema of stroma and epithelium