Infantile Glaucoma and
Custom Soft Lenses

BY ROBERT CAMPBELL, M.D. & PATRICK CAROLINE, C.O.T., F.A.A.O.
OCT. 1996

This month's case history involves a 28-year-old male with a history of infantile glaucoma OU. Early diagnosis and appropriate surgical intervention at three months of age allowed the patient to develop relatively normal vision. A recent manifest refraction revealed: OD -4.00 -0.75 x 95 = 20/30; OS -2.25 -0.50 x 85 = 20/50. K readings were: OD 45.75 @ 180/45.25 @ 90; OS 43.50 @ 180/43.00 @ 90. Visible iris diameters measured 12.5mm OD and 14.2mm OS. The patient had failed with previous soft contact lens attempts due to an inability to achieve an adequate fit on the large diameter cornea OS.

INFANTILE GLAUCOMA

Infantile glaucoma has its onset at birth or within the first three years of life. It is a hereditary defect that results in a variety of developmental anomalies within the angle of the anterior chamber. The defects interfere with aqueous drainage, resulting in increased IOP. The increased pressure causes the elastic coats of the eye to stretch and the globe to enlarge. The globe in humans is subject to this stretching only until about age three. Glaucoma occurring after this age does not cause the globe to enlarge and follows a course similar to that of adult glaucoma.

The signs of infantile glaucoma may be present and even advanced at birth or become apparent before the child has reached three months of age. The earliest symptoms include tearing, blepharospasm and photophobia. Examination reveals subepithelial corneal edema that may obscure the pattern of the iris, increased IOP and marked enlargement of the globe, usually evident by an increase in corneal diameter. The anterior chamber is deeper than normal, and there may be tears in Descemet's membrane that appear as glassy lines. Funduscopic examination shows glaucomatous cupping of the optic disc.

CORNEAL DIAMETER

In early infancy, corneal diameter normally ranges from 9.5mm to 10.0mm, increasing to full size (11.5mm to 12.0mm) at approximately one year. An infant with a corneal diameter greater than 10.5mm should undergo a complete glaucoma workup. A difference in the diameters of the two corneas is especially suspect of glaucoma in the larger eye.

Our patient revealed a marked difference in corneal diameters (12.5mm OD vs. 14.2mm OS). There was also a significant difference in anterior chamber depth as measured by Scheimpflug photography: OD 3.45mm (Fig. 1), OS 4.24mm (Fig. 2).

FIG. 1: RIGHT EYE SAGITTAL HEIGHT 3.45MM.

FIG. 2: LEFT EYE SAGITTAL HEIGHT 4.24MM.

FIG. 3: CUSTOM FLEXLENS 16.5MM DIAMETER.

CONTACT LENS Rx

We prescribed PBH Gentle Touch soft lenses OD (8.5mm -4.00 14.5mm) and Custom Flexlens 55 soft lenses OS (8.00mm -2.50 16.5mm) (Fig. 3). Visual acuities were stable at OD 20/30 and OS 20/40, and the wearing time was 14 hours a day.

This month's case history demonstrates the effective use of a custom soft lens base curve and diameter to fit a cornea with an abnormally large visible iris diameter and sagittal height. CLS

Dr. Campbell is medical director of the Park Nicollet Contact Lens Clinic & Research Center, Minnetonka, Minn. Patrick Caroline is an assistant professor of optometry at Pacific University, Forest Grove, Ore., and director of contact lens research at Oregon Health Sciences University in Portland.