Table 3.
Description of the main studies in keratoconus (KC) managed with rigid gas permeable contact lenses (RGPCLs).
| Author | Type of study | Sample size (eyes) | Severity KC | Follow-up (months) (mean) | Age (years) (mean ± SD) | Sex (male/female) | UCVA (logMAR) | BCLCVA (logMAR) | Comfort level | Other findings |
|---|---|---|---|---|---|---|---|---|---|---|
| Zadnik et al. [98] | Cross-sectional, observational | 2418 | Mild (110 eyes), moderate (1172 eyes), severe (1130 eyes) | NR | 39.3 ± 10.9 | 55.9%/44.1% | Entrance VA. (Patients) 0.0 or better: 409 >0.0 to 0.3: 693 >0.3 to 0.54: 84 >0.54 to 1.0: 18 >1.0: 18 |
(Patients) 0.0 or better: 538 >0.0 to 0.3: 612 >0.3 to 0.54: 43 >0.54 to 1.0: 10 >1.0: 1 |
72.8% comfortable 27.1% irritating at least one eye |
SCL: 4% RGPCL: 73% Piggyback: 2% Hybrid: 3% Eye rubbing: 50.4% Vogt's striae: 65% Fleischer's ring: 86% Corneal scarring: 53% Corneal irregularity: 99.7% |
| Bilgin et al. [41] | Retrospective, cohort | 1004 | Mild (5 (47%)) Moderate (4 (5%)) Severe (40.1%) |
18–30 | 34.8 ± 10.1 | 52.7%/47.3% | 0.62 mild 0.70 moderate 1.30 severe |
0.10 mild 0.10 moderate 0.22 severe |
New adaptation due to intolerance and irritation: 32.7% mild KC 23.7% moderate KC 17.6% severe KC |
PKP: 2.0% Acute hydrops: 0.3% Unilateral KC: 10.6% Cone like shape: 20.6% Subepithelial opacity: 14% Descemet folds: 8.6% Fleischer's ring: 1.8% Munson's sign: 6.2% Vogt's striae: 7.5% |
| Hwang et al. [35] | Prospective, case–control | 107 | Mild (3.7%) Moderate (43.9%) Severe (52.3%) |
22.6 | 25.4 ± 6.8 cases 22.3 ± 7.7 controls |
53.3%/46.7% | Spectacle corrected 0.68 cases 0.54 controls |
−0.032 cases | 87% comfortable 9.1% slightly uncomfortable 3.9% uncomfortable |
|
| Kamar et al. [33] | Prospective, cohort | 30 | Mild (4 eyes) Moderate (14 eyes) Severe (12 eyes) |
22 | 48.5 ± 9.9 | 50%/50% | Contact lens corrected 0.20 |
Pancorneal RGPCL 0.15 |
6.6% intolerance | Improvement in corneal compression: 77% |
SD: standard deviation; UCVA: uncorrected visual acuity; BCLCVA: best contact lens corrected visual acuity; HOA: high ocular aberration; PKP: penetrating keratoplasty. Mild KC (average sim K < 45 D). Moderate (average sim K 45–52 D). Severe (average sim K > 52 D).