Surgery and Healing in the Developing World - Dartmouth-Hitchcock

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338 Surgery and Healing in the Developing World
Figure 3.
Ophthalmoscopy
The eye should be examined using an ophthalmoscope to detect retinal or other
intraocular pathology. Ideally this should be performed in a dimly lit room with the
patient sitting comfortably.
Tonometry
Intraocular pressure can be measured using a tonometer (Fig. 4). This simple
procedure is a valuable screening test for glaucoma which, untreated, may cause
blindness. The patient should be positioned prone and lidocaine drops administered
in both eyes. The lids should be retracted and the tonometer applied to the
center of each eye in turn. The reading should be recorded in mmHg and the tonometer
cleaned.
Common Calls
Chronic Glaucoma (Open-Angle)
This condition is caused by intraocular pressure that is above 21 mm Hg. Optic
disc cupping with capillary closure results in nerve damagex followed by field defects.
Those affected most are Afro-Caribbean, myopic or have a positive family
history.
Treatment is primarily betataxolol 0.5% drops used twice daily. These are
β-blockers that reduce the production of aqueous humor (use with caution in asthma
and heart failure as systemic absorption occurs). The aim of treatment is to reduce
intraocular pressure to 21 mm Hg or less. If this cannot be done with betataxolol,
referral for surgery is indicated. Pilocarpine 0.5% drops 4x daily may be used when
surgery is not possible (miosis, blurring of vision, brow ache and, rarely, retinal
detachment are all recognized side effects of pilocarpine).
Choroiditis
Choroiditis causes blurred vision with a gray or white patch visible on the retina.
If left to progress a choroidoretinal scar may be seen. Choroiditis may be caused by
tuberculosis, toxoplasmosis and toxicara. The cause should be determined (CXR,
serology, Mantoux) and the patient treated accordingly.