Effects of different post lens saline filling solutions on the quality of vision of habitual scleral lens wearers with symptoms of mid-day fogging
Giancarlo Montani Dip.Optom FBCLA
Purpose: The aim was to evaluate the effect of different post-lens saline filling solutions used during scleral lens wear on objective quality of vision (OQV) and ocular straylight (OS) in subjects with midday fogging.
Method: We selected 12 eyes with keratoconus and 6 eyes with post graft (PG) with no corneal opacities and with visual symptoms after several hours of lens wear. OQV was evaluated considering the MTF cut off, Strehl ratio (SR) and objective scatter index (OSI) measured using a double pass instrument. OS was evaluated using the compensation comparison method. All measurements were repeated after 6 hours of wear with the lens in place one day using a common unpreserved saline (US) and the second one using an US with electrolytes K+, Ca++, Mg++ (US+E) as filling solutions. The baseline values were obtained the first day after the lenses were removed and reinserted with fresh US.
Results: The baseline values for MTF cut off, SR, OSI and OS for eyes with keratoconus and PG were respectively (mean±SD) 24.80±5.51c/deg, 0.16±0.03, 1.50±0.39, 1.12±0.13log(s) and 23.98±8.90c/deg, 0.17±0.05, 1.46±0.07, 1.17±0.23log(s). In eyes with keratoconus the MTF cut off, SR, OSI and OS comparison with baseline were not significant different (p>0,05) when US+E was used (23.03±5.84c/deg, 0.14±0.03, 1.73±0.61, 1.18±0.09log(s)) while were significant different (p<0,05) when US was used (17.61±7.44c/deg, 0.10±0.03, 2.50±1.14, 1.46±0.29log(s)). Similar results were found in eyes with PG where MTF cut off, OSI and OS comparison with baseline were not significant different when US+E was used (22.61±8.96c/deg, 1.70±0.83, 1.29±0.21log(s)) while were significant different when US was used (11.43±5.52c/deg, 2.88±1.02, 1.58±0.17log(s)). Just SR was significant different for both solutions (US+E 0.14±0.05 and US 0.11±0.08).
Conclusions: In conclusion, the decrease of quality of vision with midday fogging during the scleral lens wear can be improved using as a filling solution, an US with balanced essential electrolytes.
1st Author Biography: Giancarlo Montani is Professor of Clinical Contact Lens Application at the University of Salento, Italy. Involved in Optometry education since 1988, he has been Department Head of the Contact Lens Division at the Santa Chiara University Medical Centre in Pisa, Italy until 2004. In 2007 Professor Giancarlo Montani has co-founded the Centre for contact lens research of the University of Salento. Giancarlo Montani also works in private practice. He has published numerous articles in optometric journals, and has been invited as lecturer to several national and international Optometry Congresses.
*Data correct at the time of submission to BCLA by NCC.