Changes Of Pentacam Parameters Following Pterygium Surgery And IOL Power Calculation In Phacoemulsification Combined With Pterygium Surgery

PART ONE: CHANGES OF PENTACAM PARAMETERS IN PATIENTS WITH PRIMARY PTERYGIUM FOLLOWING PTERYGIUM EXCISION COMBINED LIMBAL CONJUNCTIVAL TRANSPLANTATIONObjective: To observe the changes of Pentacam parameters following pterygium excision combined limbal conjunctival transplantation in patients with primary pterygium.Methods: Twenty two eyes in 18 patients with primary pterygium were included in this study.All the eyes accepted pterygium excision combined limbal conjunctival transplantation.Visual acuity and Pentacam parameters were collected before operation and 3 months after operation.Results: The appearance of all eyes were improved after operation.The average anterior surface diopter and mean corneal refractive power postoperative 3 months increased compared with preoperative.On the contrary,the anterior corneal surface astigmatism and the surface coefficient of variation decreased(P < 0.05)In the preoperative and postoperative 3 months comparison,no statistically significant difference(P > 0.05)in the following parameters: the average posterior corneal surface diopter,the posterior corneal surface astigmatism,the anterior and posterior corneal surface astigmatism axial,the best corrected visual acuity and anterior chamber angle.Conclusions: The surgery of pterygium excision combined limbal conjunctival transplantation can improve the appearance of eyes suffering from pterygium,reduces anterior corneal surface astigmatism and ISV,increases average anterior surface diopter and mean corneal refractive power.Astigmatism and diopter of the posterior corneal surface,axial of the anterior and posterior corneal surface astigmatism aren’t changed after operation(P>0.05).The surgery has no impact on anterior chamber angle.PART TWO: IOL POWER CALCULATION IN PHACOEMULSIFICATION COMBINED WITH PTERYGIUM SURGERY:APPLICATION OF THE CONTRALATERAL CORNEAL REFRACTIVE POWERObjective: To evaluate the efficacy,safety and applicable objects of IOL power calculation with contralateral corneal refractive power.Methods: Prospective clinical study.Fifteen eyes in 15 patients with pterygium(contralateral eyes with no pterygium or grade 1 pterygium)and cataract were included in this study.All eyes accepted pterygium excision combined limbal conjunctival transplantation and phacoemulsification with intraocular lens implantation(PHACO+IOL).Preoperative and postoperative 3months cataract examination such as visual acuity,Pentacam and keratometer parameters,intraocular pressure,optometry were collected.Compared visual acuity preoperative and postoperative,residual spherical degree and residual astigmatism postoperative,and IOL power which calculated with contralateral corneal refractive power and affected corneal refractive power(hereinafter referred to as IOL power deviation).Visual acuity transform into logarithm of minimum angle of resolution(log MAR).SPSS17.0 software was used for statistical analysis.Results: The visual acuity was improved in all patients,including uncorrected visual acuity(1.24±0.44 VS 0.21±0.16,P<0.05)and best corrected visual acuity(0.52(0.82)VS 0.00(0.15),P<0.05).After operation,the diopter of residual spherical was small,the range was from-0.5D to +1.0D,no more than +1.0D.The absolute value of residual cylinder from 0D to 2.0D postoperative.The absolute value of residual cylinder of 6 eyes betwween 0D to0.75 D,5 eyes in 0.75D-1.5D,4 eyes more than 1.5D.Residual corneal astigmatism in the range of 0.5D-3.6D postoperative,9/15 in patients of residual corneal astigmatism were lower than 1.5D,6/15 of the value were large than1.5D.And with the increasing grade of pterygium,the proportion of residual astigmatism≥1.5D added after surgery.The range of IOL power deviation was-5.5D to +3.5D,average IOL power deviation was 1.9D.The average anterior surface diopter postoperative 3 months increased compared with preoperative.The anterior surface astigmatism and total corneal astigmatism significantly decreased(P<0.05),but the mean corneal refractive power had no significant changes after surgery(P > 0.05).Besides,mean corneal curvature increased postoperation,and curvature astigmatism decreased(P<0.05).There was no significant difference in Pentacam and keratometer parameters between all operation eyes and the contralateral eyes(P>0.05).Anterior chamber depth was deeper than that before operation(P < 0.05).The appearance of the 15 eyes was improved and the IOP was stable.Pterygium excision combined limbal conjunctival transplantation makes low pterygium recurrence rate,one year recurrence rate was 13.6%(3/22).Conclusion: Method for calculating IOL power application of the contralateral corneal refractive power in pterygium combined with cataract surgery is safe and effective,also good predictability.When a patient has a large pterygium,or large corneal astigmatism caused by pterygium or preexisting corneal astigmatism,large corneal astigmatism may still remain after surgery.we suggest pterygium surgery first,following cataract surgery with intraocular lens implantation should be have until corneal refractive stability.