Symposium: Contact Lenses f
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COMPLICATIONS ASSOCIATED WITH HARD CONTACT LENSES PAUL R. HONAN, MD LEBANON, INDIANA COMPLICATIONS with hard contact lenses can be visual or can affect the cornea and conjunctiva. Inadequate visual acuity can be caused by several lens-induced problems, most of which can be treated successfully. These include (1) wrong lens power, (2) poor lens optics, (3) too small optic zone, (4) residual astigmatism, (5) bubbles under lens, (6) excess lens movement, (7) lens decentered vertically or horizontally, (8) debris or foreign material on lens surface, (9) inadequate wetting of plastic, (10) scratches on front lens surface, (11) lenses in wrong eyes, (12) lenses warped, flattened, or steepened, and (13) wrong central posterior curve or lens power on replacement lens. Corneal epithelial abrasions are lens induced and, for the most part, are preventable. They can result from rough insertion and removal techniques, trauma, foreign body under lens, chipped edges, cracked lens, sharp juncture between central posterior curve, and intermediate or posterior curve. Acute corneal epithelial erosion (the "overwearing" syndrome) re-
Submitted for publication Nov 6, 1978. Presented in combination with the Contact Lens Association of Ophthalmologists at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26.
suIts from acute corneal hypoxia and cell desquamation and is usually preventable. Corneal epithelial edema, which can cause microcyst formation, also results from hypoxia. Tears carry dissolved oxygen, and tear exchange under lenses is necessary. Holes in lenses increase tear exchange so that edema and erosion are rare with fenestrated lenses. Chronic epithelial erosion and corneal opacification in the region of Bowman's membrane can result from undue and prolonged pressure on an area of the cornea in addition to hypoxia. This is noted in keratoconus. Although extremely rare, bacterial corneal ulcers can occur even with well fitting lenses. The Dellen effect, with staining in the 3-0'clock and 9-0'clock positions, was more common with the large, thick lenses used several years ago. Corneal vascularization is also reduced with the small, high quality, ultrathin, fenestrated lenses used today. Injection of pinqueculum or pterygium can occur from repeated bumping with lens movement. Conjunctival injection is usually caused by corneal hypoxia and is treatable by increasing tear exchange under lenses.
1102
VOLUME 86 JUNE 1979
SYMPOSIUM ON CONTACT LENSES
Spectacle blur is related to inadequate lens-corneal relationship and corneal hypoxia.
Increased corneal astigmatism is rare, especially when attention is paid to reduction of corneal hypoxia. It may be reversible or nonreversible, and it may be related to latent keratoconus. There may be reduced scleral rigidity. Reduced corneal hypoxia with better tear exchange
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has reduced the incidence of this condition. Dry eye syndromes indicate an insufficient volume of tears to carry oxygen to the cornea. Corneal hypoxia results. This is more common in females and may occur with the use of oral contraceptives, during or after pregnancy, or following hysterectomy or menopause. It may be mild or severe, possibly necessitating discontinuance of contact lenses.
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COMPLICATIONS ASSOCIATED WITH HARD CONTACT LENSES PAUL R. HONAN, MD LEBANON, INDIANA COMPLICATIONS with hard contact lenses can be visual or can affect the cornea and conjunctiva. Inadequate visual acuity can be caused by several lens-induced problems, most of which can be treated successfully. These include (1) wrong lens power, (2) poor lens optics, (3) too small optic zone, (4) residual astigmatism, (5) bubbles under lens, (6) excess lens movement, (7) lens decentered vertically or horizontally, (8) debris or foreign material on lens surface, (9) inadequate wetting of plastic, (10) scratches on front lens surface, (11) lenses in wrong eyes, (12) lenses warped, flattened, or steepened, and (13) wrong central posterior curve or lens power on replacement lens. Corneal epithelial abrasions are lens induced and, for the most part, are preventable. They can result from rough insertion and removal techniques, trauma, foreign body under lens, chipped edges, cracked lens, sharp juncture between central posterior curve, and intermediate or posterior curve. Acute corneal epithelial erosion (the "overwearing" syndrome) re-
Submitted for publication Nov 6, 1978. Presented in combination with the Contact Lens Association of Ophthalmologists at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26.
suIts from acute corneal hypoxia and cell desquamation and is usually preventable. Corneal epithelial edema, which can cause microcyst formation, also results from hypoxia. Tears carry dissolved oxygen, and tear exchange under lenses is necessary. Holes in lenses increase tear exchange so that edema and erosion are rare with fenestrated lenses. Chronic epithelial erosion and corneal opacification in the region of Bowman's membrane can result from undue and prolonged pressure on an area of the cornea in addition to hypoxia. This is noted in keratoconus. Although extremely rare, bacterial corneal ulcers can occur even with well fitting lenses. The Dellen effect, with staining in the 3-0'clock and 9-0'clock positions, was more common with the large, thick lenses used several years ago. Corneal vascularization is also reduced with the small, high quality, ultrathin, fenestrated lenses used today. Injection of pinqueculum or pterygium can occur from repeated bumping with lens movement. Conjunctival injection is usually caused by corneal hypoxia and is treatable by increasing tear exchange under lenses.
1102
VOLUME 86 JUNE 1979
SYMPOSIUM ON CONTACT LENSES
Spectacle blur is related to inadequate lens-corneal relationship and corneal hypoxia.
Increased corneal astigmatism is rare, especially when attention is paid to reduction of corneal hypoxia. It may be reversible or nonreversible, and it may be related to latent keratoconus. There may be reduced scleral rigidity. Reduced corneal hypoxia with better tear exchange
1103
has reduced the incidence of this condition. Dry eye syndromes indicate an insufficient volume of tears to carry oxygen to the cornea. Corneal hypoxia results. This is more common in females and may occur with the use of oral contraceptives, during or after pregnancy, or following hysterectomy or menopause. It may be mild or severe, possibly necessitating discontinuance of contact lenses.
