Aqueous humor is formed by the ciliary processes and flows from the posterior to anterior chamber, exiting through the trabecular and uveoscleral routes. It is continuously formed and drained at a rate of approximately 2.5mL/min. Aqueous outflow occurs through pressure-dependent (trabecular) and pressure-independent (uveoscleral) pathways. Various receptors and drugs that act on these pathways to regulate intraocular pressure are discussed. Common glaucoma medications include prostaglandin analogs, beta-blockers, alpha agonists, cholinergic agonists, and carbonic anhydrase inhibitors.

2.  Aqueous humor is formed by the ciliary
processes,
 Flows from the posterior chamber through
the pupil into the anterior chamber,
 and exits via the Trabecular route at the
angle and the uveoscleral route.

3.  It is being continuously formed and drained.
 The ciliary processes consist of about 80
processes
 The rate of aqueous humor formation is
approximately 2.5mL/min

4.  Aqueous humor outflow consist of pressure-
dependent and pressure-independent
pathways.

5.  The pressure-dependent outflow refers to
the Trabecular meshwork– Schlemm’s
canal–venous system
 the pressure-independent outflow refers to
any nontrabecular outflow and is also called
uveoscleral outflow.

7.  The adrenergic receptors (adrenoceptors)
are a class of G protein-coupled receptors that
are targets of the catecholamine's,
especially nor epinephrine (nor adrenaline)
and epinephrine (adrenaline).

8.  Many cells possess these receptors, and the
binding of a catecholamine to the receptor
will generally stimulate the sympathetic
nervous system.

9.  There are two main groups of adrenergic
receptors, α and β, with several subtypes.

10.  Alpha-1 receptors are located in the
arterioles, dilator pupillae and Muller muscle.
Stimulation gives rise to hypertension,
mydriasis and lid retraction.
 Alpha-2 inhibitory receptors located in the
ciliary epithelium. Stimulation results in
increase in the facility of aqueous outflow.

11.  Beta-1 receptors are located in the
myocardium and give rise to tachycardia and
increased cardiac output when stimulated.
 Beta-2 receptors are located in the bronchi
and ciliary epithelium. Stimulation causes
bronchodilatation and increased aqueous
production.

12.  Prostanoid receptors are located on many
ocular tissues, with involvement in functions
such as regulation of intraocular pressure
and blood flow.
 F2-alpha analogues that act as selective
agonists of the FP Prostanoid receptor.

13.  The primary mechanism is increasing
aqueous outflow, especially through the
uveoscleral outflow pathway
 By the relaxation of the ciliary muscle.
 PGs do not reduce aqueous production.
 It will reduce IOP upto 25-32%

14.  Compared with beta blockers, PG analogs
are more potent and effective ocular
hypotensive agents with once-a-day dosing
 Beta blockers do not reduce aqueous flow
during sleep,
 PGs are as effective at night as during the
day.

15. 1.Latanoprost (Xalatan®) 0.005%
 one drop applied topically once daily in the
evening
 is an isopropyl ester prodrug, meaning it is
inactive until it is hydrolyzed by esterase's in
the cornea to the biologically active acid
 A prodrug is a medication that is
administered in an inactive or less than fully
active form

16. 2.Travoprost (Travatan®) 0.004%
 is an isopropyl ester prodrug .
 One drop applied topically once daily in the
evening

17. 3.Bimatoprost (Lumigan®) 0.03%
 is an isopropyl ester prodrug .
 One drop applied topically once daily in the
evening
 It has the ability to reduce adipose (fat)
tissue.
 Used to lengthen eyelashes

18. 4.Tafluprost (Saflutan™, Taflotan®) 0.0015%
 once daily at bedtime
 It is a newer prostaglandin derivative
 The first available PGA in preservative-free
form.

19. 5.Unoprostone( Rescula (0.15%)
 Its isopropyl ester, unoprostone isopropyl
 dosage of twice daily

20.  PGs should be used more than once daily
since more frequent dosage decreases the
IOP-lowering effect

21.  Normal tension glaucoma
 Exfoliation syndrome
 Ocular hypertension Glaucoma
 Pigment dispersion syndrome,
 Chronic angle-closure glaucoma

22.  Pregnancy

23. 1.Ocular
 Hyper pigmentation of periorbital skin is
common but reversible.
 Conjunctival hyperemia and foreign body
sensation
 Eyelash lengthening, thickening, hyper
pigmentation and occasionally increase in
number
 superficial punctate keratitis, blurred vision,
cataract
 Iris hyper pigmentation, which is irreversible

26. Systemic side-effects
 Occasional headache,
 Precipitation of migraine in susceptible
individuals
 Skin rash
 Mild upper respiratory tract symptoms

27.  Beta-adrenergic antagonists
 Drugs that antagonize the effects of
catecholamine's at beta receptors.
 It reduce IOP by decreasing aqueous
secretion
 There appears to be no change in aqueous
outflow.
 Aqueous formation can decrease by as
much as 50%

28.  During sleep, aqueous flow is normally less
than half the daytime flow and beta-blockers
have limited effect

29. 1.Timolol
 is available in three forms:0.1%,0.25% and
0.5%
 used b.d.
• Timoptol LA (timolol maleate) 0.25%
and 0.5% used once daily.
• Nyogel (timolol 0.1% gel) used once
daily
 It will reduce IOP upto 20-30%

30.  Timoptic -XE (timolol in gel-forming solution)
 Istalol (timolol) and Timoptic -XE are
recommended once daily

31. 2. Betaxolol (Betoptic) 0.5% b.d.
 It has less hypotensive effect than timolol,
but the effect on preservation of the visual
field may be superior.
 It may increase optic disc blood flow,
probably because of a calcium-channel
blocking effect on the microcirculation of the
disc.

32. 3. Levobunolol (Betagan) 0.5%
 daily or b.d.
 Action is similar to timolol.

33. 4. Carteolol (Teoptic) 1%, 2% b.d.
 It is similar to timolol and also exhibits
intrinsic sympathomimetic activity.
 It has a more selective action on the eye
than on the cardiopulmonary system and
may therefore induce less bradycardia than
timolol.

34. 5. Metipranolol 0.1%, 0.3% b.d.
 It is similar to timolol but it may occasionally
cause a granulomatous anterior Uveitis.
 It is available only in preservative-free units.

35.  Ocular hypertension glaucoma
 Open angle glaucoma
 Secondary glaucoma
 Angle closure glaucoma

36.  Patients with pulmonary disease
 sinus bradycardia,
 Over uncompensated cardiac failure
 Heart block
 Cardiogenic shock, or second- or third-
degree atrio ventricular block who do not
have a pacemaker

37.  Ocular
 Occasional allergy
 Corneal punctate epithelial erosions
 Reduced aqueous tear secretion.

38.  Systemic side-effects tend to occur during
the first week of administration.
• Bradycardia and hypotension can result
from beta-1 blockade.
• Bronchospasm may be induced in pre-
existing asthma or severe chronic pulmonary
obstruction.

39.  Miscellaneous side-effects include
sleep disorders, hallucinations, confusion,
depression, fatigue, headache, nausea,
dizziness and reduction of plasma high-
density lipoprotein level.

40.  Alpha-selective agonists
 is a drug that stimulates a response from the
adrenergic receptors.
 It increase in the facility of aqueous outflow.

41. 1.Epinephrine
 A mixed alpha- and beta-adrenergic agonist,
was the
 First topical adrenergic agent used to lower
IOP in patients with open-angle glaucoma.

42. 2. Dipivefrin
 is a derivative prodrug of epinephrine

43. It decrease IOP by both decreasing aqueous
secretion and enhancing uveoscleral outflow
1.Clonidine
2.Apraclonidine
3.Brimonidine

44. Clonidine
 Synthesized in the early 1960s, Clonidine
was the first alpha agonist used systemically
and topically for glaucoma
Available in
 Dichlorophenyl aminoimidazoline
 Isoglaucon 0.125%, 0.2%, 0.5%

45. Apraclonidine
 Apraclonidine reduces IOP by reduced aqueous
production, improved Trabecular outflow, and
reduced episcleral venous pressure.
 Used as prophylaxis for Argon laser
trabeculoplasty and Nd: YAG laser
capsulotomy.
Available in
 Apraclonidine
 Iopidine 0.5%, 1%

46. Brimonidine tartrate
 Available in
Alphagan -P 0.15%, 0.1%
Brimonidine 0.2%
 Brimonidine is a highly alpha-2–selective
agonist
 Used as prophylaxis of laser-related IOP
elevation

47.  Brimonidine reduces IOP in ocular
hypertensive patients by reducing aqueous
flow (20%) and possibly by increasing
uveoscleral outflow

48. Clonidine
 mydriasis, an alpha-1 effect
 Systemic hypotension
 Sedation
Brimonidine
 Allergic conjunctivitis
 Systemic side-effects
 xerostomia, drowsiness and fatigue

49.  Cholinergic drugs mimic the effects of
acetylcholine (ACh), which is a transmitter at
postganglionic parasympathetic junctions
 Parasympathetic nervous system helps for
the Miosis and ciliary contractions in eye
 Also called as Miotics

50.  These are parasympathomimetic drugs that
act by stimulating muscarinic receptors in the
sphincter pupillae and ciliary body
 It increase trabecular outflow

51.  In POAG miotics reduce IOP by contraction
of the ciliary muscle, which increases the
facility of aqueous outflow through the
Trabecular meshwork.
 It is generally administered as a 0.5%
aqueous solution 3 times per day.

52.  In PACG contraction of the sphincter
pupillae and the resultant miosis pulls the
peripheral iris away from the trabeculum,
thus opening the angle.
 It is often necessary to reduce IOP with
systemic medication before miotics can take
effect.

53. 1.Pilocarpine
 available in the following forms:
 Pilocarpine drops 0.5%, 1%, 2%, or 4% is used
Q.I.D
 Pilocarpine gel (Pilogel®) 4% consists of
pilocarpine adsorbed on to a plastic gel, instilled
once daily at bedtime so that the induced
myopia and miosis last only during sleep.

54.  Carbachol 3% T.I.D
 It is an effective alternative to pilocarpine in
resistant or intolerant cases.

55.  Acute iritis
 Visually significant lens changes
 Acute infectious conjunctivitis or keratitis.
 Severe asthma
 Bronchial obstruction
 Acute cardiac failure
 Active peptic ulcer
 Hyperthyroidism

56. Ocular
 Miosis
 Brow ache
 Induced myopic shift
 Corneal haze
 Cataract
 Visual field defect appears denser and larger

57.  Gastrointestinal spasm
 Urinary tract obstruction
 Parkinsonism
 Recent myocardial infection
 Poorly controlled blood pressure disorders

58.  The carbonic anhydrase inhibitors (CAIs) are
chemically related to the sulphonamides
 They lower IOP by inhibiting aqueous
secretion.
 The carbonic anhydrases are family
of enzymes that catalyze the rapid
interconversion of carbon
dioxide and water to bicarbonate and proton
s

59.  Bicarbonates are responsible for the
formation of aqueous production
 By inhibiting By carbonic anhydrase actions
 It can decrease the amount of aqueous
production

60. 1.Acetazolamide
Available in
 Tablets 250 mg.
 The dose is 250–1000 mg daily in divided
doses with onset of action within 1 hour, a peak
at 4 hours and duration up to 12 hours.
• Sustained-release capsules 250 mg used
250–500 mg daily with duration of up to 24
hours.

61.  • Powder 500 mg vials for injection. The
onset of action is almost immediate, with a
peak at 30 minutes and duration up to 4
hours.
 This is the only CAI preparation available for
injection and is useful in acute angle-closure
glaucoma.

62. 2.Dichlorphenamide
 Available in tablets 50 mg
 The dose is 50–100 mg b.d. or T.I.D. with
onset of action within 1 hour, peak at 3 hours
and duration up to 12 hours.

63. 3.Methazolamide
 Available in tablets 50 mg.
 The dose is 50–100 mg b.d. or T.I.D
with onset of action within 3 hours, peak at 6
hours and duration of 10–18 hours.
 This is a useful alternative to acetazolamide
with a longer duration of action

64. 4.Ethoxzolamide
 It is a sulfonamide, inhibits carbonic
anhydrase activity in proximal renal tubules
to decrease reabsorption of water, sodium,
potassium, bicarbonate.
 It also decreases carbonic anhydrase in the
CNS, increasing the seizure threshold.
 This reduction in carbonic anhydrase also
reduces the intraocular pressure in the eye
by decreasing aqueous humor.

65. 1.Dorzolamide (Trusopt) 2% T.I.D or B.D
The main side-effects are allergic
blepharoconjunctivitis (Fig. 10.78D) and a
transient bitter taste. The drug should be
used with caution in patients with corneal
endothelial dysfunction as it may precipitate
decompensation.

66. 2. Brinzolamide (Azopt) 1% b.d. or T.I.D
 is similar to dorzolamide, but with a lower
incidence of stinging and local allergy.

67.  Diabetic patients susceptible to ketoacidosis
 Patients who have hepatic insufficiency and
cannot tolerate the obligatory increase in
serum ammonia
 Patients with chronic obstructive pulmonary
disease

68. Ocular
 Decreased vision
 Myopia
 Decreased accommodation
 Forward displacement of lens
 Eyelid or conjunctival disorder
 Allergic reactions
 Photosensitivity

69.  Stevens-Johnson syndrome
 Loss of eyelashes or eyebrows
 Retinal or macular edema
 Iritis
 Subconjunctival or retinal hemorrhages
 secondary to drug-induced anemia
 Color vision disorder (with methazolamide)
 Color vision defect
 Objects have yellow tinge

70. Systemic
 Paresthesia
 Malaise syndrome
 Acidosis
 Asthenia
 Weight loss
 Depression
 Confusion
 Impotence

71.  Gastrointestinal disorder
 Nausea
 Vomiting
 Renal disorder
 Polyuria
 Hematuria
 Glycosuria
 Hypochromic anemia

72. Ocular
 Burning/stinging eye
 Punctate keratitis
 Blurred vision
 Blepharitis
 Conjunctivitis
 Eye discharge
 Tearing
 Foreign-body sensation
 Corneal erosion
 Visual disturbance
Systemic
 Taste perversion

73.  These are drugs with similar ocular
hypotensive effects to the sum of the
individual components improve convenience
and patient compliance
 They are also more cost effective

74.  Cosopt (timolol + dorzolamide) b.d
 Xalacom (timolol + Latanoprost) OD
 TimPilo (timolol + pilocarpine) b.d.
 Combigan (timolol + Brimonidine) b.d.
 DuoTrav (timolol + Travoprost) once daily.
 Ganfort) (timolol + Bimatoprost) once daily.
 Azarga (timolol + Brinzolamide) b.d

75.  It lowers IOP by increasing the osmotic
gradient between the blood and the ocular
fluids

76.  administration of osmotic drugs, the blood
osmolality is increased by up to 20 to
30mOsm/L
 Results in loss of water from the eye to the
hyper osmotic plasma
 The mechanism of reduction of IOP is mainly
due to reduction of vitreous volume

77.  When osmotic drugs are administered prior
to surgery
 The patient’s bladder should be empty.

78. 1.Mannitol
 It is the most widely used intravenous
osmotic agent
 The dose is 1 g/kg body weight or 5 ml/kg
body weight (20% solution in water) over 30–
60 minutes.
 Peak of action is achieved within 30 minutes,
with duration up to 6 hours.

79. 2.Glycerol
 It is an oral agent with a sweet and sickly taste.
 Pure lemon (not orange) juice often needs to be
added to avoid nausea.
 The dose is 1 g/kg body weight or 2 mL/kg body
weight (50% solution). Peak action is within 1
hour, with duration up to 3 hours.
 Although glycerol is metabolized to glucose, it
may be given to well-controlled diabetics.

80. 3.Isosorbide
 It is an oral agent with a minty taste.
Metabolically inert, it may be given to diabetics
without insulin cover.
 The dose is the same as for glycerol.
 The dose is 1 g/kg body weight or 2 mL/kg body
weight (50% solution). Peak action is within 1
hour, with duration up to 3 hours.


81.  Acute and marked elevation of IOP
 Acute angle-closure glaucoma
 Secondary glaucoma

82.  Anuria
 Severe dehydration
 Impending acute pulmonary edema
 Severe cardiac decompensation

83.  IOP rebound
 Increased aqueous flare
 nausea,
 Vomiting
 Headache
 Hyperglycemia
 Renal failure