OCULAR HYPERTENSION Decisions On Treatment And Review Of The Ocular Hypertension Treatment Study - PowerPoint PPT Presentation

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OCULAR HYPERTENSION Decisions On Treatment And Review Of The Ocular Hypertension Treatment Study

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Ophthalmology Grand Rounds. January 18, 2006. Brett Williams, PGY4. OCULAR HYPERTENSION ... An intraocular pressure greater than 21 mm Hg in one or both eyes ... – PowerPoint PPT presentation

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Title: OCULAR HYPERTENSION Decisions On Treatment And Review Of The Ocular Hypertension Treatment Study


1
OCULAR HYPERTENSION--------------------------Dec
isions On Treatment And Review Of The Ocular
Hypertension Treatment Study
  • Ophthalmology Grand Rounds
  • January 18, 2006
  • Brett Williams, PGY4

2
OCULAR HYPERTENSION
  • CASE 1
  • 85 y.o. male
  • IOP 26
  • C/D 0.6
  • HVF normal
  • CCT 580

3
OCULAR HYPERTENSION
  • CASE 2
  • 40 y.o. female
  • IOP 27
  • C/D 0.3
  • HVF normal
  • CCT 610

4
OCULAR HYPERTENSION
  • CASE 3
  • 55 y.o. male
  • African descent
  • IOP 23
  • C/D 0.4
  • HVF normal
  • CCT 498

5
OCULAR HYPERTENSION
  • Definition
  • An intraocular pressure greater than 21 mm Hg in
    one or both eyes as measured by applanation
    tonometry on 2 or more occasions
  • No glaucomatous defects on visual field testing
  • Normal appearance of the optic disc and nerve
    fiber layer
  • Open angles on gonioscopy, with no history of
    angle closure
  • Absence of any ocular disease contributing to the
    elevation of pressure

6
OCULAR HYPERTENSION
  • Epidemiology
  • OHT incidence 10-15 times higher than POAG
  • Estimated that 4-10 of population have IOPgt21
    without disc damage/VF loss
  • POAG is second leading cause of irreversible
    blindness in U.S. (AMD is 1)
  • No sex predilection males may be more
    susceptible to glaucomatous damage
  • Increased incidence with age gt 40 y.o.

7
OCULAR HYPERTENSION
OHT
IOPgt30
IOP 24-29
IOPlt 24
OBSERVE
???
Rx
8
OCULAR HYPERTENSION
9
OCULAR HYPERTENSION
  • Arguments for Early Rx
  • IOP variability
  • Significant diurnal variation may mask true
    maximum IOP and delay treatment of early damage
  • No equivalent to Holter monitor for IOP
  • Early damage detection
  • Currently no reliable method to detect the
    earliest damage prior to ON/VF changes
  • Up to 50 nerve fibre loss may occur before VF
    changes detected
  • Therefore, treat all patients until reliable test
    for early damage is available

10
OCULAR HYPERTENSION
  • Arguments for Early Rx
  • Unpredictability
  • Impossible to predict which patients will convert
    to frank POAG
  • Worthwhile treating 20 pts to protect one
  • Corneal variability
  • Corneas of different individuals may have
    different mechanical properties
  • True IOP may be significantly different in 2
    patients with the same CCT
  • No test of individual corneal mechanics to
    estimate true IOP available in clinical practice

11
OCULAR HYPERTENSION
  • Arguments Against Early Rx
  • Low risk of glaucoma in OHT
  • Only 1 in 10 OHT pts develop POAG in 5 years
  • Risk for significant VA loss also relatively low
  • Cost
  • NNT 20
  • Treating 20 patients to prevent 1 from developing
    early glaucoma is not cost-effective (avg. cost
    to treat glaucoma 50/month)
  • More cost-effective to observe until early
    changes develop

12
OCULAR HYPERTENSION
  • Arguments Against Early Rx
  • Treatment Risks
  • Treating patients who may never develop glaucoma
    may result in unnecessary burden and side-effects
  • Risk factors
  • Recent research (OHTS) has defined risk factors
    for development of POAG in OHT pts
  • Provides a better framework for decision making
    in OHT
  • Therefore, treatment decisions should be
    individualized based on risk factors and
    individual patient characteristics

13
OCULAR HYPERTENSION TREATMENT STUDY
  • Introduction
  • Multi-center, prospective, randomized trial
  • Evaluate safety and efficacy of topical ocular
    hypotensive medications in preventing or delaying
    the onset of visual field loss and/or optic nerve
    damage in ocular hypertensive individuals at risk
    of POAG
  • Inclusion criteria
  • Untreated IOP 24 32 in one eye and 21 32 in
    fellow eye
  • Normal HVF, Normal optic nerves
  • Primary Outcome
  • Development of POAG in one or both eyes
  • Reproducible VF defect (x3) or glaucomatous disc
    changes (committee)

14
OCULAR HYPERTENSION TREATMENT STUDY
  • Methods
  • 1636 subjects randomized to observation or
    topical Rx to reduce IOP by gt20 from baseline
  • CCT measured for 82 of participants
  • Examined every 6/12 with 30-2 HVF, disc photos
  • 5 year follow-up

15
OCULAR HYPERTENSION TREATMENT STUDY
  • Results
  • IOP reduction of 22.5 in Rx group vs. 4.0 in
    observation group
  • Probability of POAG
  • Rx group 4.4
  • Observation group 9.5
  • Therefore, 50 reduction in risk of POAG with
    treatment

16
OCULAR HYPERTENSION TREATMENT STUDY
  • Risk factors
  • Univariate analysis
  • IOP
  • Older age
  • Race (African American)
  • C/D ratio horiz.and vert.
  • Pattern std deviation
  • CCT
  • Heart disease
  • Risk factors
  • Multivariate analysis
  • IOP
  • Older age
  • C/D ratio horiz.and vert.
  • Pattern std deviation
  • CCT

17
OCULAR HYPERTENSION TREATMENT STUDY
18
OCULAR HYPERTENSION TREATMENT STUDY
  • Central Corneal Thickness
  • OHTS patients have thicker corneas, on average,
    than the general population
  • Pts who developed POAG had thinner corneas (553.1
    vs. 574.3)
  • Patients with thinnest corneas had greater risk
    of developing POAG, especially with higher IOP
  • Patients with CCT lt 555 had 3-fold greater risk
    of developing POAG compared with pts with CCT gt
    588

19
OCULAR HYPERTENSION TREATMENT STUDY
20
OCULAR HYPERTENSION TREATMENT STUDY
  • What does OHTS Tell Us?
  • Reducing IOP reduces the incidence of glaucoma in
    OHT (relative risk reduction 54)
  • Risk factors for POAG include age, IOP, C/D
    ratio, PSD and CCT
  • African Americans have thinner corneas than white
    patients
  • Unanswered questions
  • How many patients will convert w/o Rx?
  • Will all patients convert eventually?
  • What is the risk of long-term VA loss in
    untreated converters?
  • Is it better to treat early or watch until POAG
    develops?

21
OCULAR HYPERTENSION
22
OCULAR HYPERTENSION
TREATMENT DECISION
23
OCULAR HYPERTENSION
  • Future Directions
  • Imaging Modalities
  • OCT/HRT as methods improve for detecting early
    optic nerve changes, these modalities may be used
    to help predict patients who will convert to POAG
  • Functional tests
  • Frequency doubling perimetry may be used to
    detect visual field abnormalities prior to
    standard perimetry

24
OCULAR HYPERTENSION
  • Future Directions
  • Predictive models
  • Medeiros, FA et al. (2005)
  • Scoring system to predict risk of developing POAG
    in pts with OHT
  • Point system derived from risk factors identified
    in OHTS
  • Age, IOP, CCT, Vertical C/D, PSD
  • Diabetes is a protective factor

25
OCULAR HYPERTENSION
  • Future Directions
  • Predictive models
  • S.T.A.R - Scoring Tool for Assessing Risk
  • Medeiros model recently utilized by Pfizer to
    develop a clinical scoring tool
  • Utilizes risk factors from OHTS to predict a
    patients risk of converting within 5 years

S.T.A.R. Treatment Threshold
26
OCULAR HYPERTENSION
Scoring system
27
OCULAR HYPERTENSION
  • Sample Case
  • 62 year old male
  • IOP 27 mm Hg
  • PSD 1.60 dB
  • CCT 510 m
  • C/D ratio 0.5
  • No diabetes
  • 5 Year Risk

31-40
28
THANK YOU
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