Crater-and-chop technique for phacoemulsification of hard cataracts

We describe a technique of in-the-bag phacoemulsification of large, hard, leathery brown nuclear cataracts. A large crater approximately 6.0 mm diameter is created by down-slope sculpting up to 90% of nuclear thickness, leaving the outer nuclear rim intact. The edge of the crater is held with the phaco probe using high vacuum, and small wedge-shaped pieces are created with a chopper. These small pieces are emulsified in the space created by the crater. This technique permits in-the-bag phacoemulsification of large brown cataracts without complications.

Visual performance of rigid gas permeable contact lenses in patients with corneal opacity

PURPOSE

To evaluate the visual performance of rigid gas permeable (RGP) contact lenses in patients with nebular and nebulo-macular corneal opacity and correlate the improvement in visual acuity with other visual parameters.

METHODS

In a prospective study, visual performance of RGP contact lenses was evaluated in eyes with corneal opacity involving the pupillary area. The baseline visual acuity and other visual parameters with glasses were compared with those recorded with RGP contact lenses. The visual functions evaluated were visual acuity, contrast sensitivity, glare acuity, and mesopic vision. Binocular status with RGP contact lenses was assessed. All patients were followed up for 3 months.

RESULTS

Twenty-eight eyes (26 patients) with nebular or nebulo-macular corneal opacity were included in this study. All eyes (100%) achieved significantly better visual performance with RGP contact lenses than with glasses (P< 0.0020). Visual acuity of 6/9 or better was achieved in 50% of patients with RGP contact lenses compared to none with glasses. RGP contact lenses improved the visual acuity by 0.27 decimals over the baseline value with glasses, butthe improvement for mesopic vision and glare acuity was significantly lower at 0.15 and 0.06 decimals respectively. Similarly, contrast sensitivity did not improve to the same extent as visual acuity. Stereopsis was present only in patients with best corrected visual acuity of 6/9 or better with RGP lenses.

CONCLUSION

RGP contact lenses improved the visual acuity and other visual performance in patients with reduced vision due to nebular or nebulo-macular corneal opacity. However, contrast sensitivity, glare acuity, and mesopic vision did not improve to the same extent as visual acuity.

Neurotrophic keratopathy

PURPOSE

To review the causes, clinical features, course, histopathological and biochemical changes, diagnosis, andtreatmentof neurotrophic keratopathy.

METHODS

We reviewed the literature on neurotrophic keratopathy.

RESULTS AND CONCLUSIONS

Neurotrophic keratopathy is a clinical entity which involves all degrees of degenerative corneal and conjunctival changes secondary to loss of sensory function in the nasociliary branch of the trigeminal nerve with or without decreased tear production. One of the commonest causes of loss of corneal sensation is herpes virus infection. The clinical course of neurotrophic keratopathy varies considerably. The corneal epithelium becomes diseased and breakdown occurs even in the absence of dessication, infection, and trauma. This stage, if not treated aggressively with ocular lubricants, tarsorrhaphy, or a bandage soft contact lens, will result in stromal lysis with or without perforation. Depending on the size and location of corneal perforation, procedures like the application of cyanoacrylate glue, penetrating keratoplasty, or conjunctival flap may be required.

Phaco-chop versus stop-and-chop nucleotomy for phacoemulsification

PURPOSE

To perform a comparative evaluation of phaco-chop versus stop-and-chop nucleotomy techniques of phacoemulsification.

SETTING

Dr. Rajendra Prasad Center for Ophthalmic Sciences, New Delhi, India.

METHODS

Forty eyes of 40 patients with immature senile cataract were included in the study. Twenty eyes each were randomly assigned to have phaco-chop (Group 1) or stop-and-chop (Group 2) nucleotomy during phacoemulsification. The main parameters were corneal endothelial count, effective phaco time, volume of infusion fluid used, central corneal pachymetry, best corrected visual acuity (BCVA), and intraoperative complications during nucleotomy. Follow-up visits were scheduled at 1, 4, and 12 weeks.

RESULTS

The mean effective phaco time was 27 seconds +/- 18 (SD) in Group 1 and 28 +/- 16 seconds in Group 2. The mean corneal endothelial cell loss was 6.89% and 7.17%, respectively, at the end of 12 weeks. The difference between groups was not significant. An anterior capsule tear occurred in 3 eyes in Group 1 and 1 eye in Group 2. All eyes achieved a BCVA of 20/20 at the end of 4 weeks. There were no significant between-group differences in any intraoperative or postoperative parameter.

CONCLUSIONS

The phaco-chop and the stop-and-chop nucleotomy techniques were equally efficacious for nuclear management during phacoemulsification.

Phakic-pseudophakic bullous keratopathy following implantation of a posterior chamber IOL in the anterior chamber to correct hypermetropia

There is an increasing demand for refractive surgery stemming from a heightened awareness among patients wearing spectacles or contact lenses. Cosmetic or occupational reasons prompt patients to seek the alternative option of refractive surgery.

Ocular parameters in the subgroups of angle closure glaucoma

PURPOSE

This study was conducted to compare anatomical parameters, thought to be responsible for causing angle closure glaucoma (ACG), among eyes having acute, subacute or chronic ACG.

METHODS

Ninety consecutive patients diagnosed with a subgroup of ACG, and 30 age, sex and refraction matched controls, provided a total of 240 eyes for a prospective study. The refractive error, corneal diameter, keratometry, pachymetry, lens thickness and axial length were measured and the relative lens position was calculated. The data were analysed by paired t-test, ANOVA, signed rank test and multivariate analysis.

RESULTS

Acute ACG eyes were mildly hyperopic. All the ACG subgroups had similarly short eyeballs and a steeper corneal curvature compared to control eyes. Acute ACG lenses were thicker than all the other groups (P < 0.001), but all ACG eyes had thicker lenses than the controls. Corneal diameters and anterior chamber depths were decreased in acute and chronic ACG eyes compared with subacute ACG and controls (P < 0.001). The uninvolved fellow eyes in each subgroup differed from affected eyes only in having more posteriorly positioned lenses.

CONCLUSIONS

There was a spectrum of anatomical variations seen in the subgroups of ACG. Acute ACG eyes expressed an extreme shift of anatomical features away from normal, especially, smaller corneal diameters, leading to a large mobile lens in an already crowded anterior segment. This predisposed them to a severe relative pupillary block, and to a form of ciliary block glaucoma. Chronic ACG eyes were less divergent from normal and therefore could have suffered a milder form of the same kind of angle closure, but over a more prolonged period. Subacute ACG eyes deviated least from controls, and therefore exhibited mild signs and spontaneous resolution. Further work is required to elucidate completely the pathophysiology that leads to ACG.

Combined astigmatic keratotomy with corneal valvular incision in the treatment of high surgical astigmatism

BACKGROUND

Astigmatic keratotomy is used conventionally to correct moderate surgical astigmatism. However, cases with very high surgical astigmatism due to wound compression can show a dramatic response to relaxing keratotomies made in the steeper meridian. The effect obtained cannot be predicted pre-operatively by using standard nomograms.

METHODS

Coupled arcuate keratotomies combined with corneal valvular incisions were performed in a case of high astigmatism post-cataract surgery.

RESULTS/CONCLUSION

Coupled arcuate keratotomies were combined with a corneal valvular incision enabled a surgical correction of nearly 9 D of astigmatism.

Industrial ocular morbidity in a north Indian town

A study on industrial ocular morbidity was carried out in 6 industrial establishments at Saharanpur. The mean age of the respondents was 35.3 years. 58.2% were regular floor staff. 10.6% professed suffering from an industrial ocular injury. 60% of these injuries were sustained by ocular metallic trauma. 51.9% complained of ocular symptoms at the time of the survey. The frequency of ocular complaints increased with age. The point prevalence of ocular morbidity was 746.03/1000 industrial workers. Refractive errors were the commonest ocular condition (56.7%) observed, followed by Trachoma (32.6%). The highest prevalence of morbidity was recorded among workers above 44 years. Clerical and managerial personnel had higher prevalence compared to other jobs. Only 3.6% of the floor workers were using protective devices while on the job.

Pre-existing posterior capsule breaks from perforating ocular injuries

We analyzed the characteristic features and intraoperative behavior of pre-existing posterior capsule breaks in 12 cases of traumatic cataract caused by perforating ocular trauma. The interval between the occurrence of trauma and cataract surgery ranged from three days to one year. Two distinct types of posterior capsule breaks were found: one had thick, fibrous, opaque margins with associated posterior capsule opacification (type I); the other had thin, transparent margins (type II). Type I breaks did not enlarge intraoperatively, whereas type II breaks behaved as fresh breaks by enlarging during irrigation/aspiration and had to be managed by viscoelastic plugging, dry aspiration, and adequate vitrectomy. Primary posterior capsulectomy was required in all cases with type I breaks because of posterior capsule opacification. The difference in the two types of breaks appeared to be time-dependent: cases with delayed surgical intervention (one month to one year) showed type I breaks with clinical evidence of attempted healing of the defect; cases with early surgical intervention (three days to one week) exhibited type II breaks, which did not differ from fresh intraoperative breaks.

Types of posterior capsular breaks and their surgical implications

We studied the pathogenesis, clinical features, and management of posterior capsular breaks in 28 cataract patients during planned extracapsular cataract extraction and intraocular lens implantation surgery. In the age-related cataract group (17 cases), the posterior capsular breaks were fresh, caused by the irrigation-aspiration cannula. Located in the upper part of the posterior capsule, they had thin margins and tended to enlarge with continued irrigation. Nine (52.9%) of these breaks could be plugged with viscoelastic, and after dry aspiration, a posterior chamber lens was implanted successfully. Posterior capsular breaks in traumatic cataracts (11 cases) were preexisting but were detected only during surgery. Centrally located, they had thick fibrosed margins and remained the same size during irrigation- aspiration. The minimal vitreous herniation seen in four (35.3%) of these cases was managed by automated partial anterior vitrectomy through the break. A posterior chamber intraocular lens was implanted in all these cases.

Pseudophakic pupillary-block glaucoma in children

We studied 16 children, ranging in age between 3 and 8 years, who had posterior chamber intraocular lens implantation and developed inflammatory pupillary-block glaucoma. Prophylactic peripheral iridectomy had not been performed in any of the eyes. The patients were treated medically, and YAG laser iridotomy was performed successfully one week after initial control of intraocular pressure. Of 16 eyes in which intraocular pressure remained uncontrolled, trabeculectomy was necessary in three eyes and irreversible glaucomatous visual loss occurred in two eyes. Our data demonstrate the need for stringent and more frequent postoperative follow-up of children after intraocular lens implantation, especially during the first four postoperative weeks. Careful long-term follow-up for treatment after cataract is mandatory to prevent development of amblyopia.