Prolonged exposure to air or strong light may cause oxidation and discoloration. Do not use if solution is brown or contains a precipitate.
Vasoconstriction and Pupil Dilation:
Phenylephrine Hydrochloride Ophthalmic Solution, 10%, is especially useful when rapid and powerful dilation of the pupil and reduction of congestion in the capillary bed are desired. A drop of suitable topical anesthetic may be applied, followed in a few minutes by 1 drop of the Phenylephrine Hydrochloride Ophthalmic Solution, 10%, on the upper limbus. The anesthetic prevents stinging and consequent dilution of the solution by lacrimation. It may occasionally be necessary to repeat the instillation after one hour, again preceded by the use to the topical anesthetic.
Uveitis: Posterior Synechiae:
Phenylephrine Hydrochloride Ophthalmic Solution, 10%, may be used in patients with uveitis when synechiae are present or may develop. The formulation of synechiae may be prevented by the used of the 10% ophthalmic solution and atropine to produce wide dilation of the pupil. It should be emphasized, however, that the vasoconstrictor effect of the phenylephrine hydrochloride may be antagonistic to the increase of local blood flow in uveal infection.
To free recently formed posterior synechiae, 1 drop of the 10% ophthalmic solution may be applied to the upper surface of the cornea. On the following day, treatment may be continued if necessary. In the interim, hot compresses should be applied for five or ten minutes three times a day, with 1 drop of a 1% or 2% solution of atropine sulfate before and after each series of compresses.
Glaucoma:
In certain patients with glaucoma, temporary reduction of intraocular tension may be attained by producing vasoconstriction of the intraocular vessels; this may be accomplished by placing 1 drop of the 10% ophthalmic solution on the upper surface of the cornea. This treatment may be repeated as often as necessary.
Phenylephrine hydrochloride may be used with miotics in patients with wide angle glaucoma. It reduces the difficulties experienced by the patient because of the small field produced by miosis, and still it permits and often supports the effect of the miotic in lowering the intraocular pressure. Hence, there may be marked improvement in visual acuity after using phenylephrine hydrochloride in conjunction with miotic drugs.
Surgery:
When a short-acting mydriatic is needed for wide dilation of the pupil before intraocular surgery, the 10% or 2.5% ophthalmic solutions may be applied topically from 30-60 minutes before the operation.
Refraction:
Prior to determination of refractive errors, Phenylephrine Hydrochloride Ophthalmic Solution, 2.5% may be used effectively with homatropine hydrobromide, atropine sulfate, or a combination of homatropine and cocaine hydrochloride.
For ADULTS, a drop of the preferred cycloplegic is placed in each eye, followed in five minutes by 1 drop of Phenylephrine Hydrochloride Ophthalmic Solution, 2.5%, and in 10 minutes by another drop of cycloplegic. In 50-60 minutes, the eyes are ready for refraction.
For CHILDREN, a drop of atropine sulfate 1% is placed in each eye, followed in 10-15 minutes by 1 drop of Phenylephrine Hydrochloride Ophthalmic Solution, 2.5%, and in five to ten minutes by a second drop of atropine sulfate 1%. In one to two hours, the eyes are ready for refraction.
For a “one application method”, Phenylephrine Hydrochloride Ophthalmic Solution, 2.5%, may be combined with a cycloplegic to elicit synergistic action. The additive effect varies depending on the patient. Therefore, when using a “one application method”, it may be desirable to increase the concentration of the cycloplegic.
Ophthalmoscopic Examination:
One drop of Phenylephrine Hydrochloride Ophthalmic Solution, 2.5%, is placed in each eye. Sufficient mydriasis to permit examination is produced in 15 to 30 minutes. Dilations lasts from one to three hours.
Diagnostic Procedures:
PROVOCATIVE TEST FOR ANGLE BLOCK IN PATIENTS WITH GLAUCOMA: The 2.5% ophthalmic solution may be used as a provocative test when latent increased intraocular pressure is suspected. Tension is measured before application of the phenylephrine hydrochloride and again after dilation. A 3 to 5 mm of mercury rise in pressure suggest the presence of angle block in patients with glaucoma; however, failure to obtain such a rise does not preclude the presence of glaucoma form other causes.
SHADOW TEST (RETINOSCOPY): When dilation of the pupil without cycloplegic action is desired for the shadow test, the 2.5% ophthalmic solution may be used alone.
BLANCHING TEST: One or two drops of the 2.5% ophthalmic solution should be applied to the injected eye. After five minutes, examine for perilimbal blanching. If blanching occurs, the congestion is superficial and probably does not indicate iritis.