Study Of Real World Performance Of Different Trifocal Lens For Intermediate And Near Vision In Different Light Conditions : A Study Of Real Life Performance Of Light Utilisation For Functional Near Vision

The purpose of the study is to evaluate the real life performance of various different trifocal IOLs (mIOL) in various light conditions and to undertand the effect of light utilization on the real world performace of these IOLs for near and intermediate vision.

Prospective , single centre trial at a tertiary eye hospital in a tier 2 city of India. Patients completing three month follow up were only considered for the study.

Three groups of 20 patients each, undergoing bilateral implantation of mIOL was considered. Group A recieved bilatral Gemetric/ Gemetric plus IOL( Hoya surgicals)  , group B recieved bilateral Galaxy IOL implant (Rayner) and group C recieved bilateral Panoptix (Alcon). Bilateral UCIVA  at 60 cm and UCNVA at 40 cm was accessed in bright light condition , moderate light condition and low light condition. Evaluation was done at 1 and 3 month mark and optimal LUX level of light for each group for near vision was accesed. All patient with residual of more than -0.75 SE in either eye were not considered. 

At low illumination of 30 lux , mimcing a diffuse lit room in a home in evening , UCNVA was N-10 in group A and C at 40 cm and N-8 at 60 cm. The group B showed slight better performance at low lux level with N-8 at 40cm and N-6 at 60 cm. Overall, the quality of visual acuity was noted to be better in group B in low light as comapred to other, when asked to rate the reading on a scale of 1-5 with 5 being great. In moderate illumination of 300 lux mimicking a well lit office setting and bright illumination of 1000 lux mimicking a table lamp focused on the area of reading, all the groups showed good UCNVA of N-6 at 40 cm and UCIVA of N-6 at 60cm. The UCDVA was uniform and statistically not significant across all groups.

The study showed that modern day mIOL require adequate to bright light for UCNVA and UCIVA at 40 and 60 cm with ideal Lux level being 300 Lux. The quality improved in well lit conditions when the Lux level were almost 1000 lux . Out of the three , Group B with Rayner Galaxy IOL performed best in low light condition of 30 Lux. At moderate to high illumination level, all mIOL offered excellent visual quality. On a concluding note, patients  undergoing mIOL should be explained the need of reading in moderate illumination of 300 lux or better for optimal performance.