Melissa W. Chun

Rigid contact lens fitting relationships in keratoconus

PURPOSE Although the influence of flat-fitting contact lenses on corneal scarring in keratoconus is frequently debated, the current standard of care with regard to the apical fitting relationship in keratoconus remains undocumented. METHODS Patients were examined at baseline in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study (N = 1209). Patients wearing a rigid contact lens in one or both eyes (N = 808) had their habitual rigid contact lenses analyzed, and the fluorescein patterns and base curves were compared to the first definite apical clearance lens (FDACL). The FDACL is the flattest lens in the CLEK Study trial lens set that exhibits an apical clearance fluorescein pattern. For patients wearing a rigid contact lens in both eyes, one eye was selected randomly for analysis. RESULTS Twelve percent of the rigid contact lens-wearing eyes were wearing lenses fitted with apical clearance based upon the clinicians fluorescein pattern interpretation. The remainder (88%) was wearing lenses fitted with apical touch. For mild (steep keratometric reading 52 D) corneas were fitted an average of 4.01 D flat (SD +/- 4.11 D). CONCLUSIONS Despite the potential risk for corneal scarring imposed by flat-fitting rigid contact lenses, most CLEK Study patients wear flat-fitting lenses. Overall, rigid lenses were fitted an average of 2.86 D (SD +/- 3.31 D) flatter than the FDACL.

Compliance in contact lens care

Fifty patients who were originally fitted or refitted with daily-wear contact lenses at the UCLA contact lens service were interviewed on the nature of their care system compliance and hygiene. Good compliance was defined as meeting three preset, standardized criteria (hand washing before lens manipulation, correct use of a FDA-approved care system, and adherence to a daily-wear schedule). Twenty of our patients, or 40%, were found to be noncompliant. Noncompliance occurred more frequently in the 10 to 30 year age group and in those over 50 years of age and after lenses had been worn for more than 2 years. We also noted that patients with contact lens experience predating our contact lens care were more noncompliant as a group than those who only obtained contact lenses and care through our practice.

Corneal abrasion associated with contact lens correction of keratoconus : a retrospective study

Background. Corneal abrasion is a frequently encountered complication of contact lens wear, but we are not aware of any previous study of relative frequency comparing keratoconic to nonkeratoconic patients. Methods. We retrospectively studied the incidence of corneal abrasion during 2 months of contact lens practice. Results. 784 contact lens-related patient visits (494 total patients); patients were assessed by 3 optometrists and 13 abrasions (11 patients) were diagnosed. Only the total number of individual patients and the first abrasion for each patient were statistically considered; the overall frequency of abrasion was therefore 11/494 (2.3%)/2 months. The frequency of abrasion was 5/68 (7.4%)/2 months for keratoconic patients and 6/426 (1.4%)/2 months for nonkeratoconic patients and this difference was significant (x2 test: p<0.01). Among nonkeratoconic patients, the frequency of abrasion was 2/246 (0.8%)/2 months with hydrogel contact lens wear and 4/178 (2.2%)/2 months with rigid gas permeable (RGP) contact lens wear, but this difference did not achieve significance (x2 test: p=0.10). Identified risk factors included: Contact lens wear; a torn lens and chemical keratitis for hydrogel lens wearers; an adherent “bound” lens and keratoconus for rigid lens wearers. Conclusion. Keratoconus appears to be a statistically significant risk factor for corneal abrasion among contact lens wearers.

Assessment of central vision and macular structure in patients undergoing iodine-125 brachytherapy for ciliochoroidal melanoma.

Objectives:To prospectively report standardized visual function and macular structural assessment in patients undergoing iodine-125 brachytherapy for choroidal and ciliary body melanoma. Materials and Methods:Patients were enrolled for pretreatment and annual posttreatment assessment. Evaluations included ophthalmic history; standardized refraction; visual acuity, contrast sensitivity, and color vision measurement; comprehensive ophthalmic examination; fundus photography; fluorescein angiography; optical coherence tomography; and ultrasonography. Radiation doses to the foveola and optic disc margin were calculated. Results:Forty-two patients were enrolled. Melanoma location included 3 in the ciliary body, 7 anterior, 11 equatorial, 13 posterior, and 8 macular tumors. Mean apical tumor height was 4.45 mm (range 1.79–9.83 mm) and mean longitudinal tumor diameter was 9.41 mm (range 4.52–4.73 mm). Pretreatment mean best-corrected Ferris-Bailey early treatment diabetic retinopathy study visual acuity was 50 (standard deviation ±15) letters (Snellen equivalent 20/32, range 20/15 to hand motions). The mean Pelli-Robson contrast threshold percentage was 4.1% (±2.5%). The mean Hardy-Rand-Rittler color vision score was 13/14 (±2.7). Mean distances from the posterior edge of the tumor to the foveola and the optic disc margin were 6.99 mm (±6.22 mm) and 7.28 mm (±5.98 mm), respectively. At the foveola, median total radiation dose was 36.2 Gy (±50.6 Gy) and median dose rate was 31.6 cGy/h (±39.8 cGy/h). At the optic nerve, median total radiation dose was 42.8 Gy (±30.8 Gy) and median dose rate was 36.2 cGy/h (±21.4 cGy/h). Conclusion:This prospective assessment of macular structure and function will provide more complete understanding of the ocular effects of radiation therapy for ocular melanoma.

Visual Acuity, Contrast Sensitivity and Color Vision Three Years After Iodine-125 Brachytherapy for Choroidal and Ciliary Body Melanoma

Purpose : To report visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after iodine-125 brachytherapy for choroidal and ciliary body melanoma (CCM). Design : Prospective interventional case series. Participants : Thirty-seven patients (37 eyes) with CCM. Methods : Patients had best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, Pelli-Robson contrast sensitivity and Hardy-Rand-Rittler color vision measurement; comprehensive ophthalmology examination; optical coherence tomography; and ultrasonography at baseline prior to, 1 year after, 2 years after and 3 years after I-125 brachytherapy. Main Outcome Measures : Visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after brachytherapy. Results : Nineteen (19) men and 18 women with mean age of 58 years (SD 13, range 30-78) prior to, 1 year after, 2 years after and 3 years after brachytherapy had mean best-corrected visual acuity of 77 letters (20/32), 65 letters (20/50), 56 letters (20/80) and 47 letters (20/125); contrast sensitivity of 30, 26, 22 and 19 letters; color vision of 26, 20, 17 and 14 test figures, respectively. Decrease in visual acuity, contrast sensitivity and color vision was statistically significant from baseline at 1 year, 2 years, and 3 years after brachytherapy. Decreased acuity at 3 years was associated with mid-choroid and macula melanoma location, ≥ 4.1 mm melanoma height, radiation maculopathy and radiation optic neuropathy. Conclusion : 1, 2 and 3 years after brachytherapy, eyes with CCM had significantly decreased visual acuity, contrast sensitivity and color vision.